Aardraka (Ginger)-Shunthee (Zingiber officinale) Part 1

Aardraka (Ginger)-Shunthee (Zingiber officinale) Part 1

Introduction

Shunthee (Shunthi) is a dried form of Ginger (Zingiber officinale). Its shabby look may not enthuse any one to use it as a spice or as a medicine. However its agreeable flavor and delicious taste has helped Shunthee  (Zingiber officinale) claim its rightful place on kitchen platform. For more than 5000 years, the Indians and the Chinese used the root (rhizome) of Shunthee (Zingiber officinale) as a medicine for many ailments and as a tonic. Recent references show that Ginger (Zingiber officinale) was used as domestic medicine in day to day practice worldwide. No wonder then, in Ayurveda, Shunthee (Zingiber officinale) is known as Naagaraa (that which is used in towns), Wishwaa (that which is known worldwide), Wishwa-oushadha or Wishwa-bheshaja (a medicine for the world). Because of its pleiotropic pharmacological activities it is lauded in Ayurveda as “Maha-oushadha or Maha-oushadhee”, a medicine par excellence. [1]

The word Shuntha refers to a type of grass. The word is derived from the root Shuntha meaning to “become dry”. The other Sanskrit word for Shunthee (Zingiber officinale) is “Shringaveram” as the shape of the root (rhizome) resembles that of horn (Shringa refers to horn and Veram to body). The origin of the English word “ginger” is from Old English “gingifer” which in turn is derived from Medieval Latin “gingiber” and from Greek “zingiberis”. The Greek name “Zingiberis” is derived from the Sanskrit word “shringavera” which means “shaped like a deer’s antlers”; “officinale” indicates medicinal properties of the plant. Some experts believe that the English name is probably adopted from Old French “gingibre” or modern French “gingembre”. The scientific name Zingiber officinale was given by the English botanist, William Roscoe in 1807. [2], [3], [4]

The history of use of Ginger or Shunthee (Zingiber officinale) as condiment, spice and medicine in India and China dates back to over 5000 years. While Ginger (Zingiber officinale) originated in Southeast Asia, it has a long history of being cultivated in other countries. At an early date, Ginger (Zingiber officinale) was exported to Ancient Rome from India. It was used extensively by the Romans in the pantry. As the Roman Empire fell, Ginger (Zingiber officinale) disappeared from the kitchen. At the end of the Roman Empire, the Arabs took control of spice trade. Like many other spices, Ginger (Zingiber officinale) became very costly. In 15^th century, Ginger (Zingiber officinale) was carried on ships and was introduced to Caribbean as well as Africa where it became a popular spice. Today Ginger (Zingiber officinale) is grown throughout the tropics.     

In recent years Ginger (Zingiber officinale) has become more valued as a spice than medicine. In Western countries Ginger (Zingiber officinale) was used to add taste to buttermilk and other drinks since the 11^th century AD. Widespread use of Ginger (Zingiber officinale) in foods occurred roughly about 200 years later when it was used in cooking meats.

Today the top commercial producers of Ginger (Zingiber officinale) include India, Indonesia, Jamaica, Fiji and Australia. [5], [6]

Other Names

Taxonomic Name: Zingiber officinale Roscoe  (Preferred Scientific Name)

Other Scientific Names: Amomum zingiber L. (1753), Zingiber cholmondeleyi (F. M. Bailey) K Schum, Zingiber majus Rumph, Zingiber zingiber L. (H. Karst), Zingiber missionis Wall,  Curcumialongifolia Wall    

Sanskrit: 

Fresh rhizome: Aardraka, Aardrikaa, Shringibera, Shringavera,

Dried rhizome: Shunthee (Shunthi), Naagara, Naagaraa, Naagarakaa, Wishwabheshaja, Wishwaa, Wishwoshadha     

                               

Arabic: Zanjabeele, Janjabeele Ratab

Assamese: Ada

Bengali: Ada

Chinese: Ching P i, Kan Chian, Kiang, Sheng Chiang  

English: Ginger, Common Ginger, Garden Ginger, True Ginger

Farsi: Jamveel, Zanjabil

French: Gingembre, Gingembre chinos

German: Ignaver, Ingvar

Greek: Zingiberis, Dzindzer, Piperoriza

Gujarati: Adu

Hindi: Adarak

Italian: Zenzero

Japanese: Shokyo, Oshoga

Kannada: Adraka, Alla, Shunthi

Kashmiri: Shounth, Adrak

Latin: Zingiber, Zinziber, Gingiber, Zynziber

Malayalam: Inji

Marathi: Aardraka, Aale

Oriya: Ada

Portuguese: Gingibre

Punjabi: Fresh rhizome: Adarakh

               Dried rhizome:  Sonth 

Russian: Imbir

Siddha: Fresh rhizome: Inji, Allam, Lokottai

              Dried rhizome: Chukku, Sunthi

Tamil: Inci

Telugu: Fresh rhizome: Allam

             Dried rhizome: Sonti

Tulu: Shunti

Unani: Fresh rhizome: Zanjabeele

Urdu: Adrak                                                [7], [8], [9], [10]    

Taxonomic Classification

Domain: Eukaryota

Kingdom: Plantae

Subkingdom: Tracheobionta

Phylum: Spermatophyta

Subphylum: Angiospermae

Division: Magnoliophyta

Class: Monocotyledonae , Liliopsida

Subclass: Zingiberidae

Clade: Angiosperms

Clade: Monocots

Clade: Commelinids

Order: Zingiberales

Family:  Zingiberaceae

Genus: Zingiber

Species: officinale         [11], [12], [13]

History of Taxonomy

There is no agreement among experts regarding the descent of Ginger/Shunthee (Zingiber officinale). Mabberley (1997) believed it to be a cultigen of Indian origin. [Cultigen is a plant species or a plant variety known only in cultivation with no known wild ancestor]. The first documented reference to the plant Ginger (Zingiber officinale) is in Hortus Indicus Malabaricus by Van Reede, using the local name Inschi. The genus Zingiber was described by Boehmer and Ludvig in 1790. The scientific name Zingiber officinale was given by the English botanist, William Roscoe in 1807. Roxburg described eleven species of Indian Zingiber. A much fuller survey of Indian Zingiberaceae was undertaken by Baker in 1882 for “The Flora of British India”.

The family Zingiberaceae is composed of 50 genera and around 1500 species of perennial tropical herbs.

The plant we now know as Ginger (Zingiber officinale) was first described by Carl Linnaeus as Amonum zingiber. The genus name Zingiber is now used as synonym for Amonum.   

As the species name zingiber could not be used to avoid repetition of the genus name Zingiber, officinale was adopted as the name of the species. The epithet officinale is Medieval Latin word used for medicinal substances, mostly from plants. 

Until recently, the family was divided into four tribes: Hedychiaeae, Alpinaeae, Zingibereae and Globbeae; but the study by Kress of the phylogeny of Zingiberaceae rearranged it into four subfamilies: Siphonochoideae, Tamijoideae, Alpinoideae and Zingiberoideae.  [14], [15]

Geographical Distribution

Ginger (Zingiber officinale) is a perennial herb widely distributed and cultivated throughout tropical Asia. Ginger (Zingiber officinale) is occasionally naturalized. Ginger (Zingiber officinale) is grown in tropics from up to 1500 meters altitude, but is mostly found at low altitudes. The crop prefers warm, sunny conditions. When young, the crop prefers shade especially during hot periods, but shading is generally considered unnecessary. The optimum rainfall is 2000 to 3000 mm, well distributed over the year. Below 2000 mm of rainfall, supplementary irrigation is necessary, but Ginger (Zingiber officinale) seldom succeeds as an irrigated crop. It prefers medium loamy soil with an adequate supply of organic matter with a pH of 6.0 to 7.0. Ginger (Zingiber officinale) is very sensitive to water logging. In India, it is cultivated mainly in Kerala, Andhra Pradesh, West Bengal and Maharashtra. In India different types of Indian ginger are available e. g. Cochin ginger (light brown or yellowish grey), Calicut ginger (orange or reddish brown) and Kolkata ginger (grayish blue). It is listed as invasive species in “Taiwan Invasive Species Database 2016” and as weed in Puerto Rico and Queensland, Australia. [16], [17]

Plant morphology

  [18]

                              

                                                      Ginger Plant     

Plant

Ginger (Zingiber officinale) is herbaceous perennial plant. It is erect, slender herb usually grown as an annual crop. The plant is about 1 to 1.25 meters tall.

  [18]

            

                                                      Ginger Rhizome

Rhizome

Rhizome is robust, biennial or perennial, creeping, fleshy, up to 2 cm thick; growing horizontally underground at shallow depth, irregularly branched but usually in vertical plane, covered with deciduous, thin scales which leave ring-like scars; epidermis corky, pale yellow to reddish, irregularly wrinkled in the dried rhizome (Shunthee); flesh pale yellow, with characteristic agreeable aroma; scars of leafy stems visible as shallow cup-like holes on dried rhizome (Shunthee).    

  [18]

                                                   Ginger Stem      

Stem/ Pseudostems (false stems made of the rolled bases of leaves)

Stem is annual, solid, cylindrical, erect, rises two to three feet in height, unbranched, mainly formed by the rolled leaf sheaths, pale green, often reddish at base; scales covering the lower part oblong, about 6 cm x 1 cm, scarcely white, pilose (covered with long soft hairs) outside, with prominent parallel veins and scarious (thin, dry and membranous) margins.    

    [18]

                                                 Ginger Leaves

Leaves 

Leaves lanceolate, acute, smooth, 5 to 6 inches long, about 1 inch in breadth,    arranged alternately in two opposite vertical rows (distichous); sheath prominently veined, densely appressed (pressed close to, fitting closely), pilose (covered with long soft hairs), especially in the upper part, with white, scarious, glabrous margins; ligule, part of the leaf that is found at the junction of the blade and sheath of the leaf up to 5 mm long, bi-lobed, glabrous to sparsely pilous, scarious; blade linear to lanceolate, up to 30 cm x 2 cm, acuminate at apex, finely parallel-veined, glabrous above, scarcely pilose below, light to dark green.  

    [18]

                                               Ginger Inflorescence

Inflorescence

The inflorescence arises direct from rhizome, spiciform (shaped like a spike), 15 to 30 cm long; scape (a peduncle arising at or beneath the surface of the ground) slender, 10 to 20 cm long, below the spike covered with scales as on the leafy stem bases, the upper ones sometimes with short leafy tips; spike ovoid to narrow ellipsoidal, 4 to 7 cm x 1.5 to 2.5 cm, light green; bracts appressed, ovate to elliptical, 2 to 3 cm x 1.5 to 2 cm, yellow-green, margin scarious, incurved, the lower ones with slender whitish acute tips, glabrous, finely parallel-lined; in the axil of each bract one flower may be produced.

   [18]

Ginger Flower

Flowers

Flowers fragile, short-lived, surrounded by a spatha-like (spatha=a type of a straight and long sword) bracteole; bracteole narrower and slightly longer than the bract, usually persisting and enclosing the fruit; calyx tubular-spathaceous, 10 to 12 mm long, whitish; corolla tubular, pale yellow, widening at top into 3 lobes, tube 18 to 25 mm long, dorsal lobe long ovate, 15 to 25 mm x 7 to 8 mm, with beak-like rounded apex curved over the anther, ventral lobes oblong, 13 to 15 mm x 2 to 3 mm, apex rounded, 3-veined, strongly recurved; labellum about circular in outline, 12 to 15 mm in diameter, tubular at base (tube 3.4mm), 3- lobed above; central lobe obovate, 12 mm x 9 mm, side lobes elliptical, 5 mm x 3.5, labellum pale yellow outside, inside dark purple, at top and at margins dark purple or red, mixed with yellowish spots, scattered pilose at throat; filament about 1.5 mm long, anther 2-celled, ellipsoidal, 7 to 9 mm x 3 mm, pale yellow, connectivum ( a type of connective tissue) prolonged into a slender, curved, purple, beak-like appendage 7 mm long, enclosing the upper part of the style; ovary globose, 2 mm in diameter, 3-locular; style filiform, 3.5 cm long, white, slightly recurved and widening at top, ending in a funnel-shaped white stigma which is ringed with stiff hairs around its upper margin; nectaries 2 to 3, fleshy, sublinear, white, 5 mm long, situated against the style on top of the ovary      

 [18]

    

Ginger Fruit

Fruit

Fruit a thin-walled oblong capsule, red, 3-valved, with many seeds

 [18]

       Ginger Seeds                

Seed

Small, arillate, black, globose with a small embryo and copious endosperm [19], [20], [21], [22]

Microscopic characteristics

A) Transverse section of rhizome shows cortex of isodiametric thin-walled parenchyma with scattered vascular strands and numerous isodiametric idioblasts (an isolated plant cell, having various functions, different from normal cells) about 40 to 80 μ  in diameter containing a yellowish to reddish-brown oleo-resin, endodermis slightly thick walled, free from starch immediately inside endodermis a row of nearly 138 continuous collateral bundles usually without fibers, stele or stela (central core of stem or root) of thin-walled parenchyma cells, arranged radially around numerous scattered collateral vascular bundles, each consisting of a few unlignified, reticulate or spiral vessels up to about 70 μ in diameter, a group of phloem cells, unlignified, thin-walled, septate fibers up to about 30 μ wide and 600 μ long with small oblique slit, like pits present, numerous scattered idioblasts, similar to those of cortex, and associated vascular bundles, also present, idioblasts about 8 to 20 μ wide and up to 130 μ long with dark reddish-brown contents; in single or in axial rows, adjacent to vessels, present, parenchyma of cortex and stele packed with flattened rectangular, ovate starch grains, mostly 5 to 15 μ – 30 to 60 μ long and about 25 μ wide and 7 μ thick, marked by five transverse striations. [23]

B) The transverse section of rhizome shows a zone of cork tissue which is differentiated on the arrangement of cells. The outer zone of cortical cells in the cork are suberized (deposited with suberin which can be stained with fluoral yellow) without division and hence are irregularly arranged.

The inner zone contains cortical cells arranged in a radial row and produced by tangential division. The cork cambium (partially undifferentiated cells for plant growth found between xylem and phloem) is not differentiated.

Inside the cork is broad cortex composed of cortical cells. The cortical cells contain plenty of simple, ovoid starch grain 5 to 60 μm (micrometer=micron) in size which can be stained with iodine. The outer cortex is composed of flattened parenchyma. The cortex holds suberized oil cells containing yellow-brown oleo-resin. The inner cortex consists of three layers of closed, collateral vascular bundles of phloem. The larger vascular bundles are protected in a sheath of non-lignified fibers. The vascular bundles contain sieve tubes and xylem vessels with reticulate thickened vessels, which are sometimes accompanied by secreting cells containing dark secretions.

Inside the cortex lies a single layer of endodermis which is devoid of starch.

Going inwards further from the endodermis lies the outermost layer of stele which is characterized by a single-layered pericycle. The vascular bundles of stele resemble those of cortex with the exception of a ring of small scattered bundles within the pericycle. The stele is mainly composed of parenchyma containing starch and oil cells similar to the cortical parenchyma. The innermost vascular bundles of stele may contain a fibrous sheath. [24]     

Parts used

Rhizime (Root)

Phytochemistry

The rhizome of Ginger (Zingiber officinale) contains following phytochemicals:

Oleo-resin: An essential oil and resin collectively known as oleo-resin. The composition of essential oil varies according to the geographical origin, but the chief constituents, sequiterpene hydrocarbons are fairly constant. They are responsible for the characteristic aroma.

The main oleo-resins are:

Gingerol homologues (about 33%) and derivatives with a methyl side-chain

Shogaol homologues (dehydration products of gingerol) 

Zingerone (degration product gingerols)

1-dehydrogingerdione, 6-gingesulfonic acid and volatile oils

Carbohydrates: Starch up to 50 percent   

Lipids: 6-8%   

Free fatty acids e. g. palmitic acid, oleic acid, linoleic acid, linolenic acid, caprylic acid, capric acid, lauric acid, myristic acid, pentadecanoic acid, heptadecanoic acid, stearic acid, arachidic acid.

Phosphatidic acid, Triglycerides, Lecithins, Gingerglycolipids A, B and C 

Volatile oils: 1-3%

Complex hydrocarbons: β-Bisabolene and Zingiberene;

Other sesquiterpenes: Zingiberol, Zingiberenol, ar-curcumene, β-sesquiphellandrene,  β-sesquiphellandrol (cis and trans)

Monoterpene hydrocarbons

Essential Oils

Phenols

A complex mixture of pharmacologically active compounds such as flavonoids, β- carotene, capsaicin and curcumin

Amino acids: Arginine, Aspartic acid, Cysteine, Glycine, Leucine, Isoleucine, Serine, Threonine, Tryptophan, Lysine, Methionine, Cineole, Borneol, Citrol,    Valine, Camphene, Felandrin and Phenyl alanine, Choline

Alcohols

Aldehydes: Phellandrene, Camphene, Geraniol, Neral, Linalool, δ-nerol

Proteins: about 90%

Resins

Diterpenes (Galanolactone)

Vitamins: Vitamin A, B vitamins (B1, B2, B12), Nicotinic acid (Niacin) and vitamin C

Minerals: Sodium, Potassium, Calcium, Magnesium, Phosphorus, Iron, Zinc, Aluminum, Chromium, Manganese, Silicon [25], [26]

IDENTITY, PURITY AND STRENGTH

Foreign matter: Not more than 1 percent

Total Ash: Not more than 6 percent

Acid-insoluble Ash: Not more than 1.5 percent

Alcohol-soluble extractive: Not less than 3 percent

Water-soluble extractive: Not less than 10 percent  [27]

Adulterants

Ginger (Zingiber officinale) being an underground rhizome, may be contaminated with worms, and fragments of insects and other vegetable adulterants. This can be detected through microscopic examination. Sometimes oleo-resin is extracted from other varieties of Ginger (not Zingiber officinale) rich in carbohydrates. This extract contains more than 90% oleo-resin. This extract has aroma similar to that of fresh Ginger (Zingiber officinale). This extract is known as “spent ginger”. Ginger (Zingiber officinale) can also be adulterated with “spent ginger”. Such an adulterated extract does not stand the tests of purity and standards for Ginger (Zingiber officinale). In order to increase pungency, Ginger (Zingiber officinale) is often contaminated with capsicum. “Grains of paradise” (Aframomum melegueta) is a spice in the ginger family related to cardamom. Its seeds are used as a spice. It is also known as melegueta pepper, alligator pepper, Guinea grains, ossame or fom wisa. It imparts a pungent taste and flavor. In order to increase pungency, “Grains of paradise” is also used as an adulterant.    

To identify adulterants, sample of the tincture of Ginger (Zingiber officinale) is heated to 90 to 100⁰ C with caustic alkali. The liquid is evaporated, dissolved in dilute hydrochloric acid (HCl) and extracted with ether. The ethereal layer is evaporated. If the residue is pungent, it indicates that gingerol has decomposed in the alkali solution. Capsaicin from Capsicum and paradol from “Grains of paradise” do not undergo decomposition in alkaline solutions and would therefore still give pungent odour.  [28]    

Microbial contamination

Ginger (Zingiber officinale) being an underground rhizome, may be contaminated with various micro-organisms. The contaminants identified are: Bacillus subtilis, Coliform bacteria, yeasts and moulds. [29]

There are no specific studies regarding permissible limits of heavy metals and microbes in medicinal preparations and formulations containing Ginger (Zingiber officinale); therefore I mention internationally accepted values.

Heavy metals

Element                                        Permissible Limits

Arsenic                                                 3.00

Cadmium                                              0.30

Lead                                                    10.00

Mercury                                                1.00

(Values in ppm)

Microbial Load

Name of bacteria                               WHO Limit

Escherichia coli                                       10²        

Salmonella species                              Absence

Shigella species                                  Absence         

Enterobacter species                               10⁴

Total bacterial Count                               10⁷

Yeast and Mould                                     10⁴    

Genetic Identity

Identification of clonal or genotypic variations is prerequisite for improvement of Ginger (Zingiber officinale) crop. To avoid adulteration, it is absolutely mandatory to obtain genetically pure form of Ginger (Zingiber officinale) for medicinal purposes. By analyzing various samples of Ginger (Zingiber officinale) from various states of India, scientists established genetic identity of Ginger (Zingiber officinale) accurately. The analysis was carried out using random amplified polymorphic DNA (RAPD) method. Principal Component Analysis (PCA) was also employed in some cases. [30]

PCR Analysis and SSR Sequencing  

For three Malasian Ginger (Zingiber officinale) cultivars, polymerase chain reactions (PCRs) were used to establish genetic identity of the plant. 

In many other studies other methods such as Amplified Fragment Length Polymorphism (AFLP), Amplification of Inner Simple Repeat (ISSR) markers to plant and Expresses Sequence Tag (EST) derived Simple Sequence Repeat (SSR) were employed to establish identity of Ginger (Zingiber officinale). [31] 

Chromosomal Identity

The number of chromosomes in Ginger (Zingiber officinale) 2n=22

Plant varieties produced by selective breeding are known as ‘Cultivars’.  Different cultivars vary in karyotype. Most cultivated varieties of Ginger (Zingiber officinale) are sterile. [32] 

HPTLC Analysis

Quantification of phytochemicals found in Ginger (Zingiber officinale) has been done by HPTLC analysis.

Properties and Pharmacology

Ayurvedic properties

Rasa (Taste): Katu (Acrid, Pungent) 

Weerya/ Virya (Potency, Potent Energy): Ushna (Hot, Heating)

Wipaaka/Vipak (Post Digestive Effect): Madhur

Guna

Laghu (Light), Snigdha (Oily, Greasy), Teekshna (Penetrating)

Karma

Anulomana (Prokinetic), Deepana (Appetizer), Paachana (Digestive, Digestant), Hridya/Hrudya (Beneficial to heart), Waata-Kaphaapaha (Beneficial for neuro-muscular disorders, Reduces phlegm), Triptighna (Anti-hypothyroidism), Arshoghna (Relieves piles, fissures in ano), Shoolaprashamana (Anti-colic), Trishanigrahana (Relieves thirst), Swarya (Improves voice), Wibandha-shoolanut (Relieves constipation and Colics), Ashmadoshahara (Antilithiasis), Wrishya/Wrushya (Aphrodisiac)  [33], [34], [35]

Actions on Doshas: Waata, Kapha

Actions on Srotas (Systems): Annawaha (Digestive System), Praanawaha (Cardio-respiratory System), Mootrawaha (Urinary System) [36]

Ganas:

Charaka Gana

Sushrut Gana: Pippalyaadi Gana

References:

[1] Wisdom Library, https://www.wisdomlib.org/definition/shunthi    

[2] Wisdom Library, https://www.wisdomlib.org/definition/shunthi

[3] https://en.wikipedia.org/wiki/Ginger  

[4] https://www.cabi.org/isc/datasheet/57537

[5] Ann M. Bode and Zigang Dong, Herbal Medicine: Biomolecular and Clinical Aspects. 2^nd edition, Chapter 7, The Amazing and Mighty Ginger https://www.ncbi.nlm.nih.gov/books/NBK92775/

[6] http://www.indepthinfo.com/ginger/history.shtml

[7] Zingiber officinale Rosc. : A traditional herb with medicinal properties Available from: https://www.researchgate.net/publication/264146811

[8] gernot-katzers-spice-pages.com/engl/Zing_off.html

[9] Wisdom Library, https://www.wisdomlib.org/definition/shunthi

[10] https://en.wikipedia.org/wiki/Ginger  

[11] Zingiber officinale Rosc. : A traditional herb with medicinal properties Available from: https://www.researchgate.net/publication/264146811

[12] https://www.cabi.org/isc/datasheet/57537

[13] https://en.wikipedia.org/wiki/Ginger

[14] Zingiber officinale Rosc. : A traditional herb with medicinal properties Available from: https://www.researchgate.net/publication/264146811

[15] https://www.cabi.org/isc/datasheet/57537

[16] Zingiber officinale Rosc. : A traditional herb with medicinal properties Available from: https://www.researchgate.net/publication/264146811

[17] https://www.cabi.org/isc/datasheet/57537

[18] google images

[19] Zingiber officinale Rosc. : A traditional herb with medicinal properties Available from: https://www.researchgate.net/publication/264146811

[20] http://www.botanicalauthentication.org/index.php/Zingiber_officinale_(rhizome)

[21] http://www.biologydiscussion.com/botany/pharmacognosy/ginger-description-cultivation-and-used/42925

[22] https://en.wikipedia.org/wiki/Ginger

[23] The Ayurvedic Pharmacopoeia of India, Part 1; Vol. 2; Edition 1^st;

Government of India, 1999; Ministry of Health and family Welfare

[24] Sweety Mehta, Pharmacognosy of Ginger, Notes, Pharmacognosy, January, 22, 2013

[25] Zingiber officinale Rosc. : A traditional herb with medicinal properties Available from: https://www.researchgate.net/publication/264146811

[26] Byikov I. I. et al, Extraction of biologically active substances from Zingiber officinale Roscoe in phytopreparation technology (review), Vestnik smolenskoy gosudastvennoy meditsinsinskoy akademii 2017; 16 (2): 170-180  

[27] The Ayurvedic Pharmacopoeia of India, Part 1; Vol. 2; Edition 1^st;

Government of India, 1999; Ministry of Health and family Welfare 

[28] Sweety Mehta, Pharmacognosy of Ginger, Notes, Pharmacognosy, January, 22, 2013

[29] http://www.m.elewa.org/JAPS/2009/4.1/1.pdf; Journal of Animal and Plant Sciences, 2009, Volume 4, Issue 1: 251-260; 15 August 2009

[30] S. Sajeev et al, Genetic diversity analysis in the traditional and improved ginger (Zingiber officinale) clones cultivated in North-East India, Scientia Horticulturae Volume 128, Issue 3, 11 April 2011, Pages 182-188 

[31] Praveen Awasthi et al, Mining and characterization of EST-SSR markers of Zingiber officinale Roscoe with transferability to other species of Zingiberaceae, Physiol Mol Biol Plants 2017 Oct; 23 (4): 925-931   

[32] https://www.cabi.org/isc/datasheet/57537

[33] The Ayurvedic Pharmacopoeia of India, Part 1; Vol. 2; Edition 1^st; Government of India, 1999; Ministry of Health and family Welfare

[34] Charaka Samhitaa, Sootrasthaana, 27, 296

[35] Sushrut Samhitaa, Sootrasthaana, 46, 227

[36] https://www.bimbima.com/medicines/shunthi-churna/4003/