– by European Medicines Agency (2012)
Ginger (Zingiberis rhizoma) consists of the whole or cut rhizome of Zingiber officinale Roscoe (Zingiberaceae), with the cork removed, either completely or from the wide, flat surfaces only [European Pharmacopoeia 2011]. Ginger plants have been extremely popular – for cooking as spice and to treat a host of ailments – throughout Asia, especially in India and China, for over 5000 years. The species Zingiber officinale originates from Southeast Asia. It is not known to occur wild [Teuscher 2006; Langner et al. 1998; Germer et al. 1997]. It is a perennial herb, up to 1.5 metre in height, with asymmetric flowers. Due to the long period of breeding in different continents, different types of the species have developed. The herbal substance ginger, that complies with the monograph of the European Pharmacopoeia, originates from the West Indian type (Jamaica-ginger) with the cork removed or from Indian types (Bengal-ginger, Cochin-ginger) peeled on the flattened sides only. Constituents: Volatile oil 1-4 % (minimum 15 ml/kg essential oil (anhydrous drug) according to the Ph. Eur.). More than 100 compounds are identified, most of them terpenoids mainly sesquiterpenoids (α-zingiberene, β-sesquiphellandrene, β-bisabolene, α-farnesene, ar-curcumene (zingiberol) and smaller amounts of monoterpenoids (camphene, β-phellandrene, cineole, geraniol, curcumene, citral, terpineol, borneol). The composition of the oil depends on the origin of the material [Afzal et al 2001; Ahmad et al. 2008; Ali et al. 2008; Chen & Ho 1988; Connell 1970; Erler et al. 1988; Lawrence 1984]. The pungent principles, the gingerols (4-7.5%) are a homologous series of phenols. The principal one of these is 6-gingerol. Gingerols with other chain-lengths, e.g., 8-gingerol and 10-gingerol, are present in smaller amounts. During drying and storage, gingerols are partly dehydrated to the corresponding shogaols which may undergo further reduction to form paradols, also present in stored ginger [Afzal et al. 2001; Bradley 1992; Connell 1970; Farthing & O’Neill 1990; Jolad et al. 2005; Kim et al. 2008; Steinegger & Stucki 1982]. Other constituents are starch, up to 50%, lipids 6-8%, proteins, and inorganic compounds [Awang 1992; ESCOP 2009]. The requirements of the US Pharmacopoeia for ginger are: gingerols and gingerdiones not less than 0.8%, volatile oil not less than 1.8 ml per 100 g, starch not less than 42% and shogaols not more than 0.18% [Bradley 1992; USP 2009].
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