INTRODUCTIONZingiber officinale is the best known source of the pungent, aromatic spice called ginger. This spice is produced from the rhizome (underground stem) of the plant.

Obtained by the Greeks and Romans from Arab traders, it was one of the first oriental spices to arrive in Europe. Other spices in the ginger family (Zingiberaceae) include cardamom (Elettaria cardamomum) and turmeric (Cucuma longa).

Ginger has many medicinal uses. The fresh or dried rhizome is used in oral or topical preparations to treat a variety of ailments, while the essential oil is applied topically as an analgesic. Evidence suggests ginger is most effective against nausea and vomiting associated with surgery, vertigo, travel sickness and morning sickness. However, safe use of ginger during pregnancy is questionable and pregnant women should exercise caution before taking it. The topical use of ginger may cause allergic reactions.

SCIENTIFIC CLASSIFICATION Kingdom: Plantae

Subkingdom: Tracheobionta

Superdivision: Spermatophyta

Division: Magnoliophyta

Class: Liliopsida

Subclass: Zingiberidae

Order: Zingiberales

Family: Zingiberaceae

Genus: Zingiber

Species: Zingiber officinale

GEOGRAPHY AND DISTRIBUTIONZingiber officinale is possibly native to India. It is widely grown as a commercial crop in south and southeast Asia, tropical Africa (especially Sierra Leone and Nigeria), Latin America, the Caribbean (especially Jamaica) and Australia.

MORPHOLOGYUnderground parts: Ginger has a distinctive thickened, branched rhizome (underground stem) which sometimes looks somewhat like a swollen hand. The rhizome has a brown corky outer layer (usually removed before use) and a pale yellow centre with a spicy lemon-like scent.

Leaves: Shoots (pseudostems), up to 1.2 m tall, arise annually from buds on the rhizome. These pseudostems are formed from a series of leaf bases (sheaths) wrapped tightly around one another with the long (up to 7 cm), narrow (up to 1.9 cm wide), mid-green leaf blades arranged alternately.

Flowers: The flowering heads, borne on separate shorter stems, are cone-shaped spikes and composed of a series of greenish to yellowish

leaf-like bracts. Protruding just beyond the outer edge of the bracts, the flowers are pale yellow in color with a purplish lip that has yellowish dots and striations. Flowering stems are rarely, if ever, produced in cultivated plants.

Pharmacognostic Characteristics

The macroscopic and microscopic characteristics have been well documented. When peeled, the buff colored surface of the flattened pieces show fine longitudinal striations. It breaks with a short fracture; the fibre of the fibrovascular bundles often bulge out as rigid short point from the broken surface. A narrow cortex and a broad oval central stele can be seen in the transverse section. The inner limit of the cortex is marked by a starch-free mono-layer pericycle characterizes the outermost layer of the stele. The vascular pattern of the underground rhizome of ginger at various stages of its development has also been reported.

The internal structure of rhizome exhibited an inner zone of cells arranged in radial rows and an outer zone of irregularly arranged cells separated by intermediate layers. Collateral vascular bundles are scattered and more in inner zone. The xylem containing 1-14 vessels are with scalariform thickenings and scalariform perforation plates. Libriform fibres or rarely fibre tracheids can be observed. The phloem in each vascular bundle comprise well-marked sieve tubes, companion cells, parenchyma and fibres. Oil cells and canals are many with suberized walls enclosing yellow-brown oleoresin. Numerous flattened starch grains, varying in their shape (tea or muller), size (5-15 to 30-60 µm long) and number, are present in both sides of intermediate zone. The rhizome enlargement is found to be due to the activity of: (i) primary thickening meristem and procambial cells in the ground parenchyma, (ii) the actively dividing ground parenchyma and (iii) the

secondary thickening meristem in which the fusiform and ray initials are discrete. The presence of cambium-like layers with a markedly eccentric hilum is an important feature found in ginger.

Parts Used

Rhizomes, both fresh and dried.

Types of Commercial Ginger

In trade circle, ginger is known by its country of origin, the recognized ones are noted below:

(a)African ginger

An earth-brown, mostly unpeeled, short-fractured or short-fibrous, strongly aromatic ginger, very similar to the ones from Jamaica (wherefrom the plant was originally imported) except that it is less pleasantly pungent. It is smaller in size and darker than the Cochin variety.

(b)Australian ginger

It has a distinct citrus-like odour as its volatile oil is the richest in the citral content compared to that of other varieties (vide infra)

(c)Chinese ginger

Peeled rhizome is reported to be of Jamaican quality. It is sliced as opposed to split. Being free from fibres besides its white appearance, it is particularly suitable for drugs. It has a low aroma and pungency.

(d)Indian ginger

Considered only second to Jamaican quality, Indian ginger is of two main types:

(i) Cochin ginger

Grow in Kerala (South India), available in both coated and peeled forms. Upper and lower surfaces of the coated type has a wrinkled radish-grey cork that readily exfoliates. The lateral surface is darker, pieces smaller and the branches are somewhat thicker than the Jamaican variety. It is more starchy than, equally pungent to but having less agreeable aroma than the Jamaican ones. The peeled type is light brown to yellowish-grey in color.

(ii) Calicut gingerGrown in Malabar, orange or reddish-brown, resembles Cochin ginger. However, latter is of better grade.

(iii) Calcutta gingerIt is possibly the Calicut ginger, grayish-brown to grayish-blue externally.

(e)Jamaican ginger

Pale yellowish-brown to yellowish-orange unbleached rhizomes devoid of outer suberized layers are considered to be the best. They occur in branched laterally compressed pieces, 7-12 cm long and up to 2 cm thick known as ‘races’ or ‘hands’. A inferior quality of Jamaican ginger is also marketed as ‘Ratoon ginger’.

(f)Nigerian ginger

It is smaller in size, less deeply scrapped, darker with less aroma but more pungent than the Jamaican variety which it resembles. Nigerian ginger also yields less volatile oil (0.7-1%).

IDENTIFICATIONVernacular Names

Arabic: Zanjabil

Brazilian: Mangaratia

Burmese: Gin-sin, Khyenseing (fresh); Ginsi-kyaw (dried)

Cantonese: Keung P’i; Kon keung

Chinese: Chiang P’i, Gan jiang (dried rhizome),Kan-chiang (dried, rhizome after steaming, Chin-chiang (rhizome dried at the fire), Kiang, Sheng jiang (fresh rhizome), Sheng-chiang

Dutch: Gember

English: Ginger

French: Gingembre, Herbe au gingembre

German: Ingwer

Hungarian: Gyoember

Indian:

Assamese & Bengali: Ada

Gujrati & Marathi: Adu, Ale

Hindi: Adrak, Duk (fresh), Soonth (dried)

Kanarese: Alla, Ardraka, Hashi-shunti (fresh); Sunti, Vanasunthi (dried)

Kashmiri: Sho-ont

Konkani: Ala, Alen (fresh); Sunti (dried)

Malayalam: Andrakam, Chichatakam, Chichiver, Chukka (Chukku), Erukkilannu, Hulya-Kring, Innci, Sringiveram, Tinkshnottham

Oriya: Ardroka, Oda (fresh), Sunthi (dried)

Prakriti: Signabera

Punjabi: Adi, Adrak (fresh); Sonth (dried)

Sanskrit: Adraka, Anupajam, Apakashaka, Apakrishnaka, Ardraka, Ardakam, Ardrashaka, Ardrakhya, Gulmamula, Jatilashringi, Kandara, Kaphari, Katubhadra, Katubheda, Katugranthi, Katuka, Katukayanam, Katukkata, Katulaya, Katupatra, Katushana, Katushringika, Katutikta, Machhaka, Mahaushada (Mahaoushadam), Mahavirya Mahichhatra, Mahija, Mahskandham, Mulaja, Naagara (Nagaram), Osna, Rahuchhatra, Sacchaka, Saikateshtha, Sauparna, Sharanga, Shringavera (Shrungaver), Simhala, Singavera (Sungavera), Sosana, Sunta, Sunthi, Sushakaka, Varam, Visvabhesaja (fresh), Ushanam, Visvoushadha, Visva (dried)

Tamil: Allam, Arttiragam, Attiradam, Chukku, Innci, Kodataram, Kulumamulam, Maruppu, Sangai, Sigaram, Singaveram (Singiveram), Sukhu, Sundi (dried), Ubugallam, Verkkombu (fresh);

Telugu: Allamu, Ardrakamu, Mahaushadamu, Sringaberamu (fresh) Sonti, Sunthi (dried)

Urdu: Adraka

Italian: Zenzero, Zenzevero

Japanese: Kankyo (steamed rhizome); Shoukyo (dried rhizome), Kinkyo (rhizome dried at the fire)

Malayasian: Keong phee, Kon keung

Persian: Shangabir, Zanjabli

Portugese: Gimbre, Gengiver

Rumanian: Ghimber, Imbir

Russian: Imbir

Scandinavian: Ingefaer

Sinhalese: Inguru

Spanish: Gengibre

Other available names:

Abrofoyisa, Akakadur (Akakaduru, Ajenjibre, Alea, Asunglasem Ata-le-jinja, Baojiang, Baseng, Beuing, Chitta afu, Citaraho, Djae, Engkrama, Engkrausa, Gnji, Gung, Halia, Halia bara, Hli, Ingerwurgel, Inguere, Jahe, Janzabeil, Jion, Kakadaru (Kekeduru), Kakaotchofang, Kallamu, Kanga, Kerati, Khenseing, Khing, Khing-daeng, Khing-klaeng, Khing-phueak, Khuong, Kintoki, Konga, Krobo, Lahja, Lei, Luya, Mangawizi, Ngesnges, Niamaku (Niemekou), Niamakubedi, Nkrabodo, Odzahwi, Oshoga, Palana, Palu, Pangas, Rimpang jahe, Sakanjabir, Sarahu diabita, Sa-e, Sgeugser, Shoga, Shokyo (Shouhkyoh), Shonkyoh, Sunthi, Tangawizi, Tsintsinmin, Wai, Zangabil ee-e-tar, Zingabil urratab, Zinjabil, Zingiber, Zinam.

CULTIVATIONPropagation

It is a general practice to propagate ginger by rhizomes. The synseed technology protocols for rapid multiplication and also somatic embryogenesis and regeneration methods have been developed at the IISR, Calicut. For propagation by rhizomes, carefully preserved, healthy and disease-free seed rhizomes or sets, cut into small pieces of 2.5 to 5 cm length, weighing 25 to 50 g, with a minimum of 1 or 2 good buds or growing points should be used. At the time of planting, the rhizome pieces are treated with 0.25% organo-mercurial compound or 0.3% Dithane M-45 for 10-30 minutes as a control measure against Fusarium root-rot. If required, they may be treated with 0.05% Malathion or 0.1% Quinolphos and 200 ppm Streptocycline. About 1,500-1,800 kg sets are required to plant one hectare area. Early sowing, with the onset of pre-monsoon showers, ensures good growth and yield.

Land preparation

The land should be ploughed 4-5 times to bring the soil to a fine tilth. Beds of 1 m width, 15 cm height and 3 m length, or of any convenient length, are prepared at a 40 cm spacing. About 2,000 beds of 3 m x 1 m size are prepared in one hectare of land. Being an irrigated crop, the ridges are formed 40 cm apart. The width of the channels between the beds is about 30 cm.

Planting

The planting is done in shallow pits, 4-5 cm deep, on 15 cm-high beds. For an irrigated crop, the planting is done on flat beds of convenient size for irrigation, or on ridges. The recommended spacing for this crop is 30 cm x 30 cm under the bed system of planting. A bed of 3 m x 1 m can accommodate about 40 plants.

Manures and fertilizers

As ginger is a heavy, it should be well manured. Usually, it is the practice to apply 25-30 tonnes of well rotten FYM or compost per hectare at the time of planting. The manure may be applied to each hole over the seed, which is then covered with soil, or it may be broadcasted over the entire field and mixed with the soil during the last ploughing. In addition, a fertilizer dose of 75:50:50 or 100:50:50 kg. NPK per hectare is recommended. The whole of phosphatic and half of potassic fertilizers may be applied at the time of planting. Half the Nitrogen is applied 40 days after planting and the remaining nitrogen and potassium a month after that. The application of neem cake @ 2t/ha as a basal dressing helps to reduce the incidence of soft-rot disease and increases the yield.

Irrigation

In areas of low rainfall, irrigation is a must. In most areas in India, where it is grown as an irrigated crop, watering is done at fortnightly intervals, usually during the period from the middle of September to the middle of November.

Weeding

Usually, two to three weedings are done in the whole of the growing period. The first weeding is done just before mulching and then repeated at monthly intervals, depending on the intensity of weed growth. The application of 2,4-D has been found to be effective as a pre-emergent herbicide. Manual weeding consists of either pulling out the weeds, chopping with a hoe or cutting the roots with a knife.

Mulching

A mulch of green leaves is provided twice or thrice as and when required, to prevent the soil from drying and to check weed growth. It also breaks the force of the rains and provides organic matter and also enhances germination. Mulching thrice in pure crop has been found to be better, but usually the mulching is done twice. The first mulching is done at the time of planting with 12.5 tonnes and the second after 40 days with 5 tonnes of green leaves per hectare.

Rotation and inter-cropping

The crops most commonly rotated with ginger in Kerala are tapioca, chilli, rice, gingelly, ragi, groundnut and maize. Ginger is also grown with maize as a mixed crop and as an inter-crop in arecanut and coconut gardens.

Pests and diseases

Pests

Shoot borer (Conogethes punctiferalis) attacks the ginger crop. The larvae bore into the shoots, and the shoots, and the plants wilt and eventually die. One or two prophylactic sprayings with Monochrotophos (0.1%) or Dipel (0.3%) should be given as a precautionary measure and also the seed rhizomes may be dipped in 0.1% Quinalphos for 5 minutes before planting. The usual practice is a bio-monthly spray of either of these chemicals. Hexameris sp. And hymenopteran parasitoids could be used for bio-control of this pest.

Rhizome scale

Another important pest of ginger is the rhizome scale. (Aspidiella hartii) which can be controlled by the application of Quinolphos or Fenthion (0.025%) before storage of rhizomes.

Leaf roller (Udaspes folus)

The larvae cut and fold the leaves, remain within and feed on them. The adult larvae are medium-sized and have brownish-black wings with large white spots. Spraying with Carbaryl (0.1%), Dimethoate or Phosphomidon (0.05% each) checks the pest infestation.

Nematode damage has also been reported. The control measure recommended is application of Thimet @ 10-15 kg/ha or Phorate 10 kg/ha at the time of land preparation. Denematisation of ginger rhizomes at 450C for 3 hours plus summer ploughing and covering of soil with polythene in May (15-30) is reported to reduce the population of root-knot nematode (Meloidogyne incognita).

In addition, stored ginger is attacked by the common storage pests like dung store beetle, the tobacco borer beetle, etc. Fumigation of the store houses should be carried out regularly to control these pests. The rhizome maggot, Mimegralla coerulifrous, is reported to cause rotting of the rhizomes.

Diseases

Soft-rot or rhizome-rot (Phythium apanidermatum, Phythium myriotylum and Fusarium solani) is the most serious disease of ginger. The bases of the aerial shoots become soft, watery and they rot. The affected plants become pale. Their leaf tips turn yellow, followed by complete yellowing and drying. The shoots fall and cease to produce rhizomes. The infection also spreads to the rhizomes and the inner tissues are reduced to a soft, black, putrefying mass. The disease is favored by high soil moisture content of the soil with insufficient drainage.

In order to control this disease, the first and foremost measure is the eradication of the infected plants and avoiding the monocropping of ginger. For fresh planting, only sound, disease-free and healthy seed rhizomes should be selected. They are treated with 0.25% organo-mercuric compounds for 10-30 min. before planting or with Indofil M-45 (0.25%) plus Bavistin (0.1%) for 60 min. and drying in shade for 24 hours before sowing or storage, or the rhizomes may also be dipped in Blitox 50 (0.3%) before storage. Trichoderma harzianum, T.hamatum or T.viride @ 50 g (2 x 107 cfu) may be used for biological control of the disease pathogen. The cultivars resistant to soft-rot are 76.1, OCP-855 and OCP-822.

The leaf-spot disease is caused by Taphrina sp., Colletotrichum sp. And Phyllosticta zingiberi. This disease is controlled by spraying Dithane M-45 (0.2%) or Bordeaux mixture (1%) at 15-day intervals. The bacterial wilt disease is caused by Ralstonia solanacearum, for which the control measure is spray of streptocycline (200 ppm) during the month of June. The fungus Khuskia oryzae is also reported to cause leaf-spot disease.

‘Yellows’ disease is caused by Fusarium oxysporum f.sp.zingiberi. The disease is characterized by foliar yellowing, starting from the base. The

rotting of the pseudostem, stunting of the plant, poor rhizome development and rotting of the rhizomes are the other symptoms. The control measures/FYM @ 2 t/ha and seed treatment with Mancozeb (0.25%) plus Bavistin (0.1%).

The nematode (Aphelenchus sp.) and the fungus (Fusarium sp.) together are reported to cause basal sheath rot.

Harvesting and Yield

Ginger is a 7-8 months’ duration crop. It is ready for harvest when the leaves turn yellow and start withering, after which the rhizomes become more fibrous and pungent and are better suited to the production of dried ginger. A light irrigation is provided 4-5 days before harvesting and clumps are lifted carefully with the help of a pick-axe or a digging fork or hoe. If the crop is meant for green ginger, it is harvested in 5-6 months.

An average crop of ginger may yield about 10-30 tonnes of fresh rhizomes per hectare.

Processing

Fresh ginger, is consumed as a vegetable spice, both when immature and mature. It is of lesser importance in world trade, but in the local market it is a major commodity. For this purpose, green ginger rhizomes, soon after harvesting are thoroughly washed in water 2-3 times to remove any soil and dirt. Then, the damaged and diseased rhizomes are separated and graded depending upon the requirement in the market.

Dried ginger

In order to obtain a more pungent and aromatic spice, ginger should be harvested at the time of proper maturity and dried properly. For this

purpose, the harvested rhizomes are soaked in water overnight and rubbed well between to remove the adhering soil. After thorough cleaning, they are removed from the water. The outer skin is removed with a split bamboo with a pointed end, taking care to see that only the outer skin is peeled as otherwise the essential oil glands beneath the skin will also get damaged and thus the oleoresin will be lost. The peeled rhizome is washed and uniformly sun-dried for a week. The dry ginger is rubbed together to remove dry foreign matter. This type of dried produce is known as unbleached ginger. Depending upon the variety, on an average, 16-25 kg dried ginger is obtained from 100 kg green ginger, i.e., the yield of dry ginger is 16-25% of the green ginger.

Dried ginger forms the major bulk of international trade. It is exported as whole or in split forms and is ground at the consuming centres. It is also used for preparation of its extractives, ginger oleoresin and ginger oil.

Bleached ginger

To prepare bleached ginger (white), the fresh rhizomes are peeled off and soaked in 2 per cent lime water for about 6 hours. The produce is then removed and dreid for 5-6 days and rubbed with a piece of gunny cloth to give the desired dried appearance.

Preserved ginger

This is prepared from immature rhizomes, mostly for export purposes. Discounting green ginger preserved in brine, the two forms of processed, preserved ginger entering the market are:

1. Preserved ginger in sugar syrup

2. Dry or crystallised ginger, wherein ginger is impregnated with sugar syrup, dried and coated with crystalline sugar and must be harvested while they are still immature, tender, succulent, and mild in pungency,

usually under 7 months of age. For processing, the salted ginger is removed from the acidified brine, washed and soaked in cold water, which is heated in syrup for 10 minutes, after which the ginger is removed and pricked with a fork. The ginger is then boiled in syrup for 45 minutes. It is left in the syrup to soak for 2 days or more, and then reboiled for 45 minutes after which it is packed in fresh syrup. The quantity of syrup used depends on the market for which the ginger is intended.

Ginger oleoresin and essential oil

Ginger oleoresin (3.5-9.5%) is obtained by the solvent extraction of ginger powder using organic solvents like acetone, ethylene dichloride, etc., and it possesses the full organoleptic properties of the spice such as aroma, flavor and pungency. It is a blend of oil and resinoids and finds similar applications as the ground spice in the flavoring of processed foods. The oleoresin is also used in certain beverages and to a limited extent in pharmaceutical preparations.

On the other hand, ginger oil (0.5-3.0%) is distilled from the dried spice. The product is characterized by the aroma and flavor of the spice but lacks the pungency. It finds its main application in flavoring of beverages and in the confectionery and perfumery industries.

Grading

Dried ginger is marketed on the basis of geographical origin and the form of preparation. The chemical and physical characteristics of the spice differ from one producing region to another.

Indian dried ginger is classified as Malabar ginger, Assamese ginger and Himachal ginger. But the two types of the spice which are in great demand in the world market are Cochin and Calicut ginger, which come under the Malabar ginger type. The bulk of our exports are of rough-

scraped, whole rhizomes. Sometimes, coated ginger is also exported. Bleached or limed Calicut ginger is mainly exported to the Middle Eastern countries.

Cochin dried ginger is about 20 mm long and has a light brown to yellowish-gray color, whereas, Calicut dried is orange to reddish-brown in color and is generally considered to be inferior in quality to the Cochin spice. Both types are graded prior to export into the following categories, according to the number of fingers on the rhizomes-B (three fingers), C (two fingers) and pieces (individual finger). The grades of whole ginger and the specification are given in the table below.

Grade Specification Size of rhizomeCalicut (NGK) Garbled (distorted),

Non-bleachedNot less than 20 mm in size

Calicut (NUGK) Ungarbled,Non-bleached

Small, cut pieces, <20 mm in length

Cochin (NGC) Garbled, non-bleached

Not less than 20 mm in length

NUGC Ungarbled,non-bleached

Smll, cut pieces, not less than 20 mm in length

BGC Garbled, non-bleached Not less than 20 mm in length

Cochin (BUGC) Ungarbled, bleached Small, cut pieces of less than 20 mm in length

The technical and physical specifications of ginger as prescribed by ASTA-(1) and FADA mould (% by weight) are: (1) insect defiled (% by weight) (2) volatile oil (%) (min.) 2; moisture (% max.) 12; ash (% max.) 5, acid-insoluble ash (% max.) 1.0; average bulk index (mg/100g) N/A.

Value-added products

Ginger oil, oleoresin, candy, preserves, vitaminised effervescent ginger powder, plain effervescent powder, starch from spent ginger, ginger brandy, wine, beer, medicinal beverages, encapsulated ginger oil, and dehydrated ginger are some of the value-added products of ginger.

Storage of seed ginger

For good germination, the seed rhizomes should be stored properly in pits under the shade. The rhizomes usually harvested during December-January, have to be preserved for about 4 months before planting (April-May). Good, disease-free, big, plump rhizomes should be selected for seed purposes and treated with 0.25% organo-mercurial compound for 10 minutes, against soft-rot disease, and then dried in the shade. If the seed rhizome is infested with rhizome scale, it is advisable to treat it with 0.05% Malathion or Dimethoate. Then, the seed rhizomes are loosely placed in pits of convenient size to a height of 10-15 cm from the top and covered with a wooden plank. The remaining surface is plastered with mud. In certain areas, the rhizomes are loosely heaped over a layer of sand or paddy husk and covered with dry leaves.

Properties

The rhizome is acid, aromatic, pungent, sweet and thermogenic.

General Tests for Identification

Characteristic form, color (internally pale yellow to brown), odour, taste, volatile oil and microchemical tests of the rhizomes.

Purity Tests

Ginger itself or in its powdered form should comply in general with the requirements of the BP.

(a) Extractives(i) Water soluble not<10%(ii) Alcohol soluble not<4.5%

(b)Microorganisms

Salmonella ssp should not be present at all in dried ginger. The permissible limits of microorganisms are given in Table

Aerobic bacteria

Enterobacteria/Gram –ve bacteria

Escherichia coli

Fungi

Decoction < 107/g < 105/g or ml < 102/g < 105/gInternal use

< 105/g or ml

<105/g or ml 0/g or ml < 104/g or ml

(c)Maximum admissible limits of impurities in dried ginger

The impurities of powdered ginger and their admissible limits are given in Table

Foreign organic matter 2%Total ash 6%Water soluble ash 1.7%Acid insoluble ash 2%Aldrin and dieldrin 0.05 mg/kgHeavy metals +Lead

10 mg/kg

Cadmium 0.3 mg/kgAssay Methods for Volatile Oil

WHO guidelines are available for determination of volatile oil content, which should not be less than 2% v/w.

Microchemical Tests

Qualitative thin layer chromatography as well as qualitative analyses for the gingerols, shogaols, β-bisabolene, αϒ-curcumene, β-

sesquiphellandrene and α-zingiberene contents of ginger by gas chromatography and HPLC are also reported.

Adulterants

“Spent ginger” exhausted in the preparation of essence is the most common adulterant of powder ginger. It is easily detectable by purity test for extractives and admissible ash contents. Other vegetable adulterants can be detected by microscopic examination.

The pungency of the ginger galenicals is often increased by adding capsicum or grains of paradise. A simple test to ascertain this is as follows: An aliquot of the tincture is heated over water-bath with caustic alkali, evaporated, residue acidified with dilute hydrochloric acid and then shaken with ether. The ethereal solution on evaporation in a watch leaves a residue that lacks the pungency of ginger.

CHEMICAL CONSTITUENTSThe constituents of ginger are numerous and vary depending on the place of origin and whether the rhizomes are fresh or dry. Though the pungency of fresh ginger is primarily due to the presence of gingerols, which are a homologous series of phenolic ketones, the sensory perception of ginger in the mouth and the nose are contributed by two distinct groups of chemicals:

(i) Volatile oils: The volatile oil components in ginger consist mainly of sesquiterpene hydrocarbons, predominantly zingeberene (35%), curcumene (18%) and farnesene (10%), with smaller amounts of bisabolene and b-sesquiphellandrene. A smaller percentage of at least 40 different monoterpenoid hydrocarbons are present with 1,8-cineole, linalool, borneal, neral, and geraniol being the most abundant. Many of these volatile oil constituents contribute to the distinct aroma and

taste of ginger. Diarylheptanoids have been reported as components of both fresh and dry ginger.

(ii) Nonvalatile pungent compounds: Biologically active constituents include the nonvolatile pungent principles such as the gingerols, shogaols, paradols and zingerone that produce a “hot” sensation in the mouth. The gingerols, a series of chemical homologs differentiated by the length of their unbranched alkyl chains, were identified as the major active components in the fresh rhizome. The major gingerol is [6]-gingerol, while [8]- and [10]-gingerol occur in smaller quantities. The gingerols are thermally unstable and are converted under high temperature to [6]-, [8]- and [10]-shogaol, another homologous series and the dehydrated form of the gingerols. Paradol is similar to gingerol and is formed on hydrogenation of shogaol.

Jolad et al. examined organically-grown fresh ginger and identified [4]-, [7]-, [8]- and [10]-gingerol in addition to [6]-gingerol, as well as methyl [4]-gingerol and methyl [8]-gingerol. [4]-, [6]-, [8]-, [10]- and [12]-shogaol. Paradols are 5-deoxygingerols. [6]- paradol, along with [7]-, [8]-, [9]-, [10]-, [11]- and [13]-paradols, have been detected in fresh ginger, as was methyl [6]-paradol, methyl [8]-paradol, methyl [6]-isogingerol and [6]-isoshogaol. Jolad et al. also examined commercially processed dry ginger using the same techniques that they had utilized in their earlier study. They detected [6]-, [8]-, [10]- and [12]-gingerdiones, which had not previously been reported in fresh ginger. The concentrations of gingerols in dry ginger were reduced slightly in comparison to fresh ginger, whereas the concentrations of shogaols increased.

(iii) Other constituents: In addition to the extractable oleoresins, ginger contains many fats, waxes, carbohydrates, vitamins and

minerals. Ginger rhizomes also contain a potent proteolytic enzyme called zingibain.

PHARMACOLOGICAL PROPERTIESGinger has been extensively studied for its pharmacological activities. It has been used safely for thousands of years in cooking and medicinally in folk and home remedies. The National Center for Complementary and Alternative Medicine (NCCAM) has evaluated the results of the available studies on ginger, rating the reports from “suggestive” (short-term use of ginger for safe relief from pregnancy related nausea and vomiting), to “mixed” (when used for nausea caused by motion sickness, chemotherapy, or surgery), to “unclear” (for treating rheumatoid arthritis, osteoarthritis, or joint and muscle pain). Ginger is also well known all over the world especially for its use in disorders of the gastrointestinal tract such as constipation, dyspepsia, diarrhea, nausea and vomiting.

Medicinal Uses

Ginger, both fresh and dry, is used as a therapeutic agent, as an adjunct to many tonic and stimulates as well as a powerful agent against air pollution in every season.

General Uses

Raw ginger is carminative, digestive and laxative; beneficial in anorexia, dyspepsia, inflammation, and pharyngopathy.

Dry ginger is extremely valuable in common cold, cough, colic, dyspepsia, fever including flu, flatulence, haemorrhoids, hoarseness and sore-throat, spasms and other painful affections of bowels and of stomach unattended with fever, urticarial. It is excellent for the

circulatory system, useful in diseases of heart and throat and helps increase stamina.

Dry ginger is alexetoric, anodyne, anthelmintic, antibilious, anti-inflammatory, antirheumatic, aphrodisiac, appetizing in anorexia, blood purifier, carminative, cooling, cordial, diaphoretic, digestive, emollient, expectorant, laxative, rubefacient, sialagogue, stimulant both local and to gastrointestinal tract, stomachic, tonic and thermogenic.

It is employed with beneficial in asthma, bronchitis, cardipathy, cephalangia, cholera, constipation, diarrhea, dropsy, elephantiasis, nausea, otalgia, pain, piles, swelling and vomiting.

Antimicrobial Effects

In assessments of ethnobotanical uses of plants, ginger was found to significantly inhibit a wide range of bacteria and fungi pathogenic to humans. Significant antifungal activities were evident with extracts from members of the Zingiberaceae, in particular those of A. galangal, C. zedoaria, Z. purpureum and Z. officinale. Of specific interest are those extracts that inhibit several fungi that are resistant to commonly used antifungals. As species belonging to the Zingiberaceae family are generally regarded as safe for human consumption, they are excellent candidates for development as antifungal phytomedicines. In vitro studies have shown that active constituents of ginger inhibit multiplication of the colon bacteria that ferment undigested carbohydrates causing flatulence. Ginger also inhibits the growth of Escherichia coli, Proteus sp., Staphylococci, Streptococci and Salmonella. GE has an antimicrobial action at levels equivalent to 2000 mg/ml of the spice. Fresh ginger juice showed an inhibitory action against A. niger, S. cerevisiae, Mycoderma sp. and L. acidophilus at 4%, 10%, 12% and 14%, respectively, at ambient temperatures.

Analgesic and Hypoglycemic Effects

Based on earlier studies it is speculated that [6]-gingerol is most probably responsible for the analgesic and hypoglycemic effects of GE. Ginger has demonstrated analgesic effects in experimental studies in animals. This effect is thought to be a result of inhibition by shogaol of the release of substance P, much like that by capsaicin, the pungent principle of red pepper (Capsicum frutescens).

Antioxidant and Anti-inflamatory Effects

Since tumor promotion is closely linked to inflammation and oxidative stress, a compound that exhibits anti-inflammatory and/or antioxidant properties could act as an anticarcinogenic agent. This has clearly been demonstrated by inhibition of phospholipid peroxidation induced by the FeCl3-ascorbate system and its inhibitory effect on the xanthine oxidase system, which is responsible for the generation of reactive oxygen species such as superoxide anions. Another study reported concentration-dependent (0.5-10 µM) inhibition by [6]-gingerol of arachidonic acid induced platelet aggregation and formation of thromboxane B2 and prostaglandin D2. In one study, the oxidative stress induced by malathion (a pesticide) in rats was overcome by introducing ginger into the rats’ diets. The antioxidant activity of ginger was shown to be as effective as vitamin C in lowering lipid peroxidation in rats by influencing the enzymatic blood level of superoxide dismutase, catalase, and glutathione peroxidase. A strong positive effect of ginger on plasma lipid composition, which may be important for the prevention of atherosclerotic events, was also demonstrated in apolipoprotein E-deficient mice (i.e. mice that are prone to develop atherosclerosis), showing a significant reduction in basal concentration of LDL-associated lipid peroxides in mice that consumed ginger in their drinking water.

IN VITRO STUDIES

Studies have suggested that these compounds suppress the proliferation of human cancer cells and exert inhibitory effects on the viability of human HL-60 (promyelocytic leukemia) through the induction of apoptosis cells. Exposure of Jurkat human T-cell leukemia cells to various ginger constituents galanals A and B (isolated from the flower buds of Japanese ginger) resulted in apoptosis mediated through the mitochondrial pathway accompanied by a downregulation of antiapoptotic protein Bcl-2 and an enhancement of proapoptotic protein Bax expression. The rhizome of ginger has been reported to possess antitumor promotional potential as determined by abrogation of activation induced

Wang et al. showed that b- elemene, a novel anticancer drug extracted from the ginger plant, induced caspase-3, -7 and -9 activities, decreased Bcl-2vexpression, caused cytochrome c release and increased the levels of cleaved caspase-9 and poly (ADP-ribose) polymerase in non-small lung cancer cells. In A549 human lung cancer cells, a novel phenylbutenoid dimer (+/-)-trans-3-(3,4-dimethoxyphenyl)-4-[(E)-3,4-dimethoxystyryl]- cyclohex-1-ene, isolated from Zingiber cassumunar, has suppressed cell-cycle progression by increasing p21 expression and downregulating cyclins and CDKs.

Breast Cancer

[6]-gingerol inhibits cell adhesion, invasion, motility and activities of MMP-2 and MMP-9 in the MDA-MB-231 human breast cancer cell line, showing a concentration-dependent decrease in cell migration and motility. The activities of MMP-2 or MMP-9 in MDA-MB-231 cells were decreased by treatment with [6]-gingerol in a dose-dependent manner. 1’-acetoxychavicol acetate (ACA), a tropical ginger compound, exhibits potential anticancer effects against breast carcinoma cells by inducing

apoptosis in human breast carcinoma-derived MCF-7 and MDA-MB-231 cells.

Gastrointestinal Cancer

Helicobacter pylori is the primary etiological agent associated with peptic ulcer disease and the development of gastric and colon cancer. The anti-H. pylori effects of ginger and its constituents were tested in vitro by Mahady et al. It was found that gingerol inhibited the growth of H. pylori CagA+ strains and this activity may contribute to its chemo-preventive effects against colon cancer. [6]-gingerol facilitated TRAIL-induced apoptosis by increasing TRAIL-induced caspase-3/7 activation in gastric cancer cells. [6]-gingerol stimulates apoptosis through upregulation of NAG-1 and G(1) cell-cycle arrest through downregulation of cyclin D1 in human colorectal cancer cells involving mechanisms of proteins degradation as well as beta-catenin, PKCepsilon, and GSK-3beta pathways.

Pancreatic Cancer

[6]-gingerol inhibited cell growth through cell-cycle arrest at the G1 phase in two human pancreatic cancer cell lines, HPAC expanding wild-type p53 and BxPC-3 expressing mutated p53. [6]-gingerol can circumvent the resistance of mutant p53-expressing cells towards chemotherapy by inducing apoptotic cell death while it exerts a cytostatic effect on wild type p53-expressing cells by inducing temporal growth arrest. P53 expression was also found to decrease through [6]-gingerol treatment in both cell lines, suggesting that the induction of cyclin-dependent kinase inhibitor, p21cip1, was p53-independent. [6]-gingerol induced mostly apoptotic death in the mutant p53-expressing cells, while no signs of early apoptosis were detected in wild type p53-expressing cells and this was related to the increased phosphorylation of AKT.

Renal Cancer

A recent study examined the early signaling effects of [6]-gingerol caused a slow and sustained rise of [Ca+2] ions in a concentration-dependent manner. [6]-gingerol induced a significant rise in [Ca+2] ions in MDCK renal tubular cells by stimulating both extracellular Ca2 influx and thapsigargin (an endoplasmic reticulum Ca+2 pump inhibitor) sensitive intracellular Ca+2 release via as yet unidentified mechanisms.

Prostate Cancer

A recent study demonstrated the modulation of [6]-gingerol on testosterone-induced alterations of apoptosis-related proteins in in vitro, androgen-sensitive LNCaP cells via upregulation of p53, Bax, caspase-9 and caspase-3 and downregulation of testosterone-induced anti-apoptotic proteins, Bcl-2 and surviving expression. A study showed that mitogen-activated protein kinase phosphatase-5 (MKP5) overexpression decreased cytokine-induced NF-KB activation, COX-2, IL-6 and IL-8 in normal prostatic epithelial cells, suggesting potent anti-inflammatory activity of MKP5.

Colon Cancer

Ginger and its components have been used traditionally for the treatment of gastrointestinal ailments such as motion sickness, dyspepsia and hyperemesis gravidarum, and are also reported to have colon cancer chemopreventive activity. Gingerol also inhibited the growth of human colorectal cancer cells. These reports claims that the results strongly suggest that ginger compounds may be effective chemopreventive and/or chemotherapeutic agents for colorectal carcinomas. The efficacy of ginger was found to be significant in a combined set of experiments where mice were fed with ginger before and after tumor cells were injected and in a second set where mice

were fed with ginger only after their tumors had grown to a certain size. Another study looked at its modifying potential on the process of colon carcinogenesis induced by 1,2-dimethylhydrazine (DMH) in male Wistar rats using aberrant crypt foci assay. The results showed that dietary intake of ginger does not significantly change the proliferative or apoptosis indexes of colonic crypt cells. The effect of ginger on the initiation and postinitiation stages of DMH-induced colon carcinogenesis in male Wistar rats was studied and the results showed a lower incidence of tumors.

Motion Sickness

Ginger has long been used as a remedy to decrease nausea and vomiting associated with several conditions. A follow-up study showed that 1 g of ginger was effective at reducing the subjective severity of sea sickness in naval cadets on the high seas, although the results were not statistically significant. A randomized, double-blind, placebo-controlled study was performed to assess the effects of ginger extract on motion sickness and gastric slow-wave dysrhythmias induced by circular vection. Volunteers with a history of motion sickness were pretreated with ginger (1,000 mg and 2,000 mg). Individuals then underwent circular vection during which nausea, tachygastria, and vasopressin were assessed. Ginger improved each of the above parameters, significantly prolonging the latency period before nausea onset and shortening the recovery time after vection cessation. Other research has shown no benefit of ginger for motion sickness.

Nausea and Vomiting

Pregnancy-induced

Ginger is used to ameliorate symptoms of nausea in pregnancy. It is perhaps most popular for its antinausea and antiemetic effects in

pregnancy. Up to 85% of pregnant women experience nausea in early pregnancy, and some 50% of those with nausea experience vomiting as well. In an extensive review of studies using ginger as an agent to fight morning sickness, the authors concluded that “ginger….may be beneficial.” In one study of 70 pregnant women, participants received either 250 mg of freshly prepared ginger powder or a placebo. Resupts indicated a significant reduction in nausea and number of vomiting episodes. A randomized, controlled equivalence trial involving 291 women less than 16 wks pregnant was undertaken at a teaching hospital in Australia. Women took 1.05 g of ginger or 75 mg of vitamin B6 daily for 3 wks and found that ginger was equivalent to vitamin B6 in reducing nausea, retching and vomiting, averaged over time. In a double-blind, randomized, controlled trial (RCT), 170 pregnant women with symptoms of nausea and vomiting were randomly allocated into group A receiving one capsule of ginger twice daily (one capsule contained 0.5 g of ginger powder) (n=85) and group B receiving an identical capsule of 50 mg dimenhydrinate twice daily (n=85). The vomiting episodes of group A were found to be greater than group B during the first and second day of the treatment with a statistically difference. There was a statistically significant difference in the side effect of drowsiness after treatment with group B greater (77.64%) than group A (5.88%). Thus, ginger was shown to be as effective as dimenhydrinate in the treatment of nausea and vomiting during pregnancy and had fewer side effects.

Postoperative

In a study by Phillips et al. ginger also significantly reduced nausea and vomiting when compared to placebo and metoclopramide. In a recent double-blind study, ginger failed to demonstrate an antiemetic effect following laparoscopic surgery. Preoperative doses of 100 or 200 mg were administered and followed by repeated 100 or 200 mg doses. An

earlier double-blind study on the effect of ginger on postoperative nausea also failed to demonstrate beneficial effects compared to placebo. In a double-blind RCT, 120 patients who underwent major gynecologic surgery were randomized into group A receiving two capsules of ginger taken one hour before the procedure (one capsule contained 0.5 g of ginger powder) (n=60) and group B receiving the placebo (n=60). A statistically significant difference in nausea between group A (48.3%) and group B (66.7%) was observed.

Chemotherapy induced

Cancer chemotherapy can cause severe nausea, vomiting and abdominal discomfort, which can limit therapy. In relation to chemotherapy-induced nausea and vomiting in one study, the addition of ginger to the standard antiemetic regimen had no advantage in reducing nausea or vomiting in the acute phase of cisplatin (Platinol)-induced emesis. A systematic review of six RCTs analyzing ginger for clinical nausea and vomiting found insufficient data to draw firm conclusions. To explore the use of protein meals with ginger for the treatment of the delayed nausea of chemotherapy, a recent study was designed for 28 patients with cancer.

Effect on digestion

Ginger increases saliva as well as gastric secretions useful in poor appetite and nutrient absorption and hence stimulates digestion and particularly useful in sub-acid gastritis. Ginger contains enzymes, more effective than those of papaya that enhance the action of the gall bladder while protecting the liver against toxins. Ginger can also help quell stomach distress and alleviate uncomfortable, full feeling caused by overeating.

Dietary ginger (50 mg %) showed increased pancreatic lipase activity and stimulated chymotrypsin and pancreatic amylase in albino rats maintained for 8 weeks with spice diet. The observation further supports the stimulating action on digestion of ginger consumed in diet.

Effect on intestine

Ginger raises the tonus of the musculature and enhances peristalsis in intestines in human.

Effect on ulcers

Ginger is effective against ulcers. It prevents ulcer formation including those induced by alcohol, aspirin, indomethacin, other stomach irritants and stress by decreasing the total volume of acid in the stomach.

Effect on immune system

Ginger’s antimicrobial properties as above stimulate the body immune system and hence the defense mechanism, a factor responsible for its effectiveness against colds. Because of its stimulating action on circulatory system and heart, ginger is also considered as the drug of choice for chronic cold hands and feet.

Antihistaminic effect

Ginger has a significant antihistaminic effect. Its action against coughs compares favorably well with that of codeine. It reduces hyperactive allergic response by acting on eicosanoids in the body.

Antitussive effect

Ginger helps dispel bronchial congestion. A simple cup of ginger tea containing a quarter teaspoonful of ginger in hot water with some honey has recently been reported to be effective while a

pharmaceutical cough syrup proved to be ineffective. It is, however, a common knowledge that ginger tea is very beneficial in all types of cold affections.

Both gingerol and shogaol posses antitussive property. However, shogaol is more potent having more cough suppressant activity compared to dihydrocodeine phosphate.

Effect on rheumatoid arthritis and musculoskeletal disorders

The antirheumatic activity has also been confirmed.

Clinical study with rheumatoid arthritis patient who could get only temporary or partial relief by conventional treatment revealed remarkable pain relief, reduced swelling, morning stiffness and enhanced joint mobility with a daily dose up to 1 g of powdered ginger. Follow-up study ranging from 3 months to two and a half years at the dose of 0.5 to 1 g powder/day recorded pain relief and swelling reduction in 75% and 100% patients of arthritis (both rheumatoid and osteo-) and muscular discomfort respectively.

A clinical study referred to in WHO monograph reports that direct administration of 5-10% ginger extract brought about full or partial pain relief, recovery or improvement of joint function and decrease of swelling in 115 patients with rheumatic pain and chronic lower back pain.

Effect on osteoarthritis

In a randomized, placebo-controlled, double blind, double dummy, cross over comparative study of the effects of ginger extract and ibuprofen in patients with osteoarthritis of the hip or knee, statistically significant effect of ginger extract could atleast be demonstrated in the first period of treatment before cross-over.

From a recent study on the symptomatic and structural management of osteoarthritis pain relief and improvement of functional disability, it has been pointed out that conclusion of beneficial effect of many nutriceuticals are based on studies on prescription medicine rather than the over-the-counter pills or food supplements now being extensively used. More extensive investigations particularly on ginger have, therefore, been advocated.

Two labdane class of diterpene aldehydes in ginger extract has been found to inhibit human 5-lipoxygenase in vitro.

Effect on blood clot and platelet aggregation

A single dose of 1 g powdered ginger administered to the patients suffering from coronary artery disease produced a significant reduction in adenosine diphosphate (ADP)- and epinephrine-induced platelet aggregation without affecting the sugar content in the blood.

Ginger, particularly its aqueous extract, has a powerful anticlotting effect. At least four of its constituents prevent blood clotting. Apparently, it inhibits the platelet aggregation and other arachidonic acid metabolism in the blood vascular system in vivo. Ginger alone significantly decreases the formation of platelet lipid peroxidation.

The effect has been found to be far superior to garlic and onion. Interaction of ginger and garlic with warfarin has also been studied. A study on the effect on the platelet aggregation revealed more powerful inhibitory action of the aqueous extract of ginger on thromboxane formation and pro-aggregatory prostaglandins.

A controlled human study also confirmed more pronounced lowering effect on platelet thromboxane production by ginger as compared to that of onion which somewhat raised it. The claim of ex-vivo platelet

thromboxane production in human due to daily consumption of ginger could not, however, be corroborated by a later study.

The antiplatelet action of gingerol, the major active principle of ginger, has also been shown to be mainly due to inhibition of thromboxane formation and pro-aggregatory prostaglandins that can also help prevent heart attack and stroke.

Antivertigo effect

Ginger has been shown to have antivertigo effect like Dramamine. Significant decrease in induced vertigo rather than nystagmus indicated the possible inhibitory effect of ginger on the vestibular impulses to the autonomic centres of brain.

Antidepressant effect

Ginger is a good antidepressant. Sunth is given to women after confinement. It stimulates the respiratory and vasomotor centres. Based on the usefulness in neurological disorders, ginger powder (60 mg) given with water to a patient at the onset of attack has been reported to alleviate migrane headache within 30 min. Administration of 1.5-2 g powder per day for 3-4 days after onset of migrane has been found to markedly decrease the frequency of attack as well. The effect is comparable with the inhibitory action of ginger on eicosanoids, platelets and serotonin.