3. Turmeric
Synonyms Curcuma; Indian
Saffron; Tumeric.
Biological Source Turmeric is
obtained from the rhizome of Curcuma longa Linn. (Curcuma domestica Valeton)
belonging to the natural order Zingiberaceae.
Preparation The plant is
normally harvested after 9-10 months when the lower leaves start becoming
yellow. The rhizome is carefully dug out from the soil with a blunt knife
without damaging it. The fibrous roots are discarded. The raw green turmeric
is cured and processed by boiling the rhizomes with water for a duration
ranging between 12-14 hours. Subsequently, the cooked rhizomes are dried in the
sun for 5-7 days. Cooking process helps in achieving two objects,
namely:
(a) Gelatinization of
starch, and
(b) Yellow colouration,
due to curcumin, spreads over the entire rhizome.
Characteristic Features
Turmeric has an aromatic pepper-like but somewhat bitter taste. It gives curry
dishes their characteristic yellowish colouration.
Chemical Constituents It
contains volatile oil (5-6%), resin and substantial quantity of zingiberaceous
starch grains. The marked and pronounced yellow colour in turmeric is
due to the presence of curcuminoids which essentially contains curcumin
as given below:
The curcuma oil*
obtained from turmeric contains (±)-ar-turmerone as given below:
The volatile oil contains a
host of chemical substances, such as: d-α-phellandene, d-sabinene,
cineol, borneol, zingiberene, and sesquiterpenes.
Turmeric also contains
some other chemical constituents, namely: p,p-dihydroxy dicinnamoylmethane;
p-α-dimethy benzyl alcohol; p-hydroxy-cinnamoylferuloylmethane;
1-methyl-4-acetyl-1-cyclohexene; and caprylic acid.
Chemical Tests
1. Turmeric powder when
triturated with alcohol it imparts a deep yellow colour to the resulting solution.
2. The powdered drug when treated
with sulphuric acid it imparts a crimson colour.
3. The aqueous solution of
turmeric with boric acid gives rise to a reddish-brown colouration which on
subsequent addition of dilute alkali changes instantly to greenish-blue.
4. Turmeric powder when
reacted with acetic anhydride and a few drops of concentrated sulphuric acid
(36 N), it readily gives a violet colouration. Interestingly, the resulting
solution when observed under the ultraviolet light (preferably in a uv-chamber),
it exhibits an intense red fluorescence, which is due to the presence of Curcumin.
Uses
1. It is extensively used
across the globe as a condiment as curry powder.
2. It is employed as a
colouring agent for ointments.
3. It is used medicinally as a
tonic, as a blood purifier, as an anthelmintic and finally as an aid to digestion.
4. It is used extennally in the
form of a facial cream to improve complexion and get rid of pimples.
5. A small quantity of turmeric
when boiled with milk and sugar; it helps to cure common cold and cough
symptoms.
-------------------------------------------------
*
H. Rupe et. al. Helv. Chim. Acta,
17,
372 (1934).
Source:Pharmacognosy And Pharmacobiotechnology By Ashutosh Kar
Source:Pharmacognosy And Pharmacobiotechnology By Ashutosh Kar
0 Comment:
Post a Comment