''Curcuma caesia'', black turmeric or black zedoary, is a perennial herb with bluish-black

rhizome In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...

s that is native to

northeast India , native_name_lang = mni , settlement_type = , image_skyline = , image_alt = , image_caption = , motto = , image_map = Northeast india.png , ...

Preparation

The cultivation and harvest practices are similar to that of common

turmeric Turmeric () is a flowering plant, ''Curcuma longa'' (), of the ginger family, Zingiberaceae, the rhizomes of which are used in cooking. The plant is a perennial, rhizomatous, herbaceous plant native to the Indian subcontinent and Southeast Asi ...

. In the fields, the rhizomes are washed thoroughly and are placed in a wide mouthed cauldron. The water is poured in the cauldron such that the rhizomes are completely covered. The cauldron is covered with a lid, and the rhizomes are boiled for about 30 minutes until foam oozes out with a strong odour. The rhizomes are taken out when the water is reduced to one-third of the original and they are soft and their inner portion has turned from blue to dark or pale brown. The rhizomes are then dried in hot sun for 10 to 15 days until hardened. These dried rhizomes are then packed for marketing.

Chemical constituents

The research on the volatile rhizomes oil of ''Curcuma caesia'' resulted in the identification of 30 components, representing 97% of the oil, with

camphor Camphor () is a waxy, colorless solid with a strong aroma. It is classified as a terpenoid and a cyclic ketone. It is found in the wood of the camphor laurel ('' Cinnamomum camphora''), a large evergreen tree found in East Asia; and in the k ...

(28%), ar-turmerone (12%), (''Z'')- ocimene (8%), ar-curcumene (7%),

1,8-cineole Eucalyptol is a monoterpenoid. A colorless liquid, it is a bicyclic ether. Eucalyptol has a fresh mint-like smell and a spicy, cooling taste. It is insoluble in water, but miscible with organic solvents. Eucalyptol makes up ~70% - 90% of eucaly ...

(5%),

elemene Elemenes are a group of closely related natural chemical compounds found in a variety of plants. The elemenes, which include α-, β-, γ-, and δ-elemene, are structural isomers of each other and are classified as sesquiterpenes. The elemenes c ...

(5%),

borneol Borneol is a bicyclic organic compound and a terpene derivative. The hydroxyl group in this compound is placed in an '' endo'' position. The exo diastereomer is called isoborneol. Being chiral, borneol exists as enantiomers, both of which are foun ...

(4%),

bornyl acetate Bornyl acetate is a chemical compound. Its molecular formula is C12H20O2 and its molecular weight is 196.29 g/mol. It is the acetate ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least o ...

(3%) and curcumene (3%) as the major constituents. Other research demonstrated diphenylalkanoids,

phenylpropene Phenylpropene is the organic compound with the formula C6H5CH2CH=CH2. It is a colorless liquid. The compound consists of a phenyl group attached to allyl. Phenylpropene isomerizes to trans-propenylbenzene. In plant biochemistry, the phenylprop ...

derivatives, terpenoids,

flavonoid Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans. Chemically, flavonoids ...

steroid A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and a ...

s, and

alkaloid Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar ...

s as major constituents.

References

{{Taxonbar, from=Q368767 Herbs

caesia ''Caesia'' is a genus of herbs in the family Asphodelaceae, subfamily Hemerocallidoideae,Stevens, P.F. (2001 onwards)"Hemerocallidoideae" ''Angiosperm Phylogeny Website''. Retrieved 2016-06-10. native to Australia, New Guinea, Madagascar and Sou ...

Taxa named by William Roxburgh