Impact of turmeric terpenoids on bioavailability of curcumin
Loading...
Date
2016
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
DIVISION OF AGRICULTURAL CHEMICALS ICAR-INDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI –
Abstract
Rhizome of turmeric (Curcuma longa) is one of the richest sources of bioactive
compounds. Curcuminoids, the active constituent are one of the most researched
topic worldwide for its broad spectrum of biological activities. Efforts have been
made to incorporate the molecules into commercial food products as a
pharmaceutical and nutraceutical agent but the low bioavailability limits its
application. The present study aimed at utilization of bioactive terpenoid constituents
present in turmeric fixed oil for the improvement of bioavailability of curcuminoids.
Turmeric fixed oil (yield 5.7% w/v) from rhizome powder was extracted with
hexane and purified by column chromatography for separation of terpenoids. Purified
oil mixture was analyzed by GC-MS and found three major peaks in the
chromatogram. α, β- turmerone was separated together and their structure was
confirmed by GC- EI-MS. ar- turmerone was separated as pure peak and
characterized by mass, IR and 1H-NMR. For the separation of curcuminoids, defatted
turmeric powder was extracted with ethyl acetate and the extract was purified
using column chromatography, followed by prep-TLC to get individual compounds
(Rf 0.78, 0.53, 0.25). Purified curcuminoids were analyzed by HPLC using RP-18
column with PDA detector (max 425 nm) under isocratic conditions using mobile
phase of acetonitrile 0.1% formic acid (60:40, v/v). Three purified curcuminoids
were characterized by FT-IR,1H-NMR and HRMS data. Based on spectroscopic data,
the purified compounds were confirmed as 1,7-bis(4-hydroxy-3-methoxyphenyl)-
1,6-heptadiene-3,5-dione or curcumin-I (C); 1-(4-hydroxyphenyl)-7-(4-hydroxy-3-
methoxyphenyl)-1,6-heptadiene-3,5-dione or curcumin-II (DC); and 1,7-bis(4-
hydroxyphenyl)-1,6-heptadiene-3,5-dione or curcumin-III (BDC).
The HPLC method was validated; LOD and LOQ values were calculated as
0.27, 0.33 & 0.42 µg mL-1
and 0.80, 1.00 & 1.25 µg mL-1
for C, Dc and BDC,
respectively. Accelerated solvent extraction experiment was conducted using
ethanol, ethyl acetate and acetone as extraction solvent, keeping homogenization
technique as a control. Ethanol provided maximum physical yield (9.2 %) by ASE
experiment followed by acetone (6.1 %) and ethyl acetate (5.8 %), although there is
significant differences between ethyl acetate and acetone. Similarly, ethanol yielded
maximum extract upon extraction by homogenization. But, opposite trend was
recorded in case of acetone and ethyl acetate. No significant differences were
observed in ASE as well as homogenization in terms of purity of individual
curcuminoids. Antioxidant assay evaluated using DPPH and ABTS assay found that
IC50 value of curcuminoids mixture were 78.8 and 145.7 µg mL-1
respectively. The
antioxidant activity of three curcuminoids, followed the order C > DC > BDC in both
assays. The bioavailability study was carried out individually with each
curcuminoids and along with turmerones to observe their effect on bioavailability of
curcumin. In-vitro study revealed that in the presence of turmerone and turmerone
mixture the bioavailability of curcumin has increased 2 fold and more. The
information might be useful for the development of improved bioavailable curcumin
formulation.
Description
t-9395
Keywords
Impact of turmeric terpenoids on bioavailability of curcumin