Abstract:
The genus Curcuma belongs to the family Zingiberaceae comprises rhizomatous annual
or perennial herbs. Curcuma has a long history of traditional uses ranging from folk
medicine to its culinary uses. This study was undertaken to study the biological activities
of rhizomes and leaves of four Curcuma species available in Sri Lanka namely, Curcuma
albiflora, Curcuma aromatica, Curcuma longa, and Curcuma zedoaria. Fresh rhizomes
and leaves of four Curcuma species were collected from their natural habitats in Wet and
Dry Zones of Sri Lanka. Rhizomes and leaves were cleaned and cut into small pieces and
oven-dried at 45 °C and 40 °C respectively for 12 hrs. Dried samples were ground into a
fine powder. Methanol extracts from rhizomes and leaves were screened for total
polyphenol content (TPC), antioxidant activity, and α-amylase inhibition activities. The
TPC of dried rhizomes of Curcuma longa was the highest of all tested as 5.530 ± 0.012 g
of GA equivalents per 1 g of the dried rhizome. The Methanol extracts of the rhizome and
leaf samples of four species showed moderate antioxidant activity in the DPPH radical
scavenging assay with IC50 values ranging from 150.253 ± 0.273 ppm to 389.051 ±
0.426 ppm. Interestingly the rhizome extracts of Curcuma aromatica, Curcuma longa,
and Curcuma zedoaria exhibited higher α-amylase inhibitory activities (13.915 ± 0.023,
6.455 ± 0.117 and 9.492 ± 0.024 respectively) than the Acarbose drug which is an antidiabetic drug (28.273±0.615 ppm). The results revealed that the Sri
Lankan Curcuma species have a potency to be used as a source of antioxidant and antidiabetic agents and it is important to increase the value of the unexplored medicinal herbs
available in Sri Lanka.
Keywords: Antioxidant, Anti-diabetic, Biological Activities, Curcuma
