The phytochemical composition and antioxidant capacities of 6 new NRCRI turmeric
(Curcuma longa L.) accessions (39, 35, 60, 30, 50 and 41) were determined using standard techniques.
The moisture contents of the tumeric samples ranged from 15.75 to 47.80% and the curcumin contents
of the turmeric samples fell within the range of curcumin obtained from turmeric in other countries of
the world. Furthermore, the turmeric accessions contained considerable amounts of antioxidants
(measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and reducing power assays), alkaloids,
flavonoids, anthocyanins, and phenolics. There was significant correlation between the anthocyanin contents of the tumeric
accessions versus their alkaloid (0.744) and flavonoid contents (0.986) suggesting an additive effect between the
anthocyanins and alkaloids in turmeric; significant correlation between the inhibition of the turmeric accessions on DPPH
radical versus their flavonoid (0.892) and anthocyanin (0.949) contents and significant correlation between the reducing
power of the turmeric accessions versus their flavonoid (0.973) and anthocyanin (0.974) contents suggesting that anthocyanins
as flavonoids largely contribute to the antioxidant activities of turmeric. The positive regression recorded between
inhibition of DPPH radical by the turmeric accessions and quercetin versus reducing power (R2 = 0.852) suggest that any
of these methods could be used to assess the antioxidant activities of tumeric. Finally, the study indicated the potentials of
the turmeric accessions especially accessions 30 and 50 as promising sources of antioxidants.