In Vitro Alpha-Amylase and Antioxidant Activities of Bark Extracts of Charcoal Tree (Trema orientalis Linn.)
By: Dana Joanne Von L. Trono, Olga M. Nuñeza, Mylene M. Uy, W.T.P.S.K. Senarath
Key Words: Antidiabetic, Brine shrimp lethality assay, DPPH scavenging activity, GC-MS, Total phenolic content.
Int. J. Biosci. 8(1), 33-46, January 2016.
The objective of the present study is to evaluate the α–amylase inhibitory and antioxidant activities, as well as the total phenolics content of methanol (80:20 v/v) and aqueous bark extracts of T. orientalis through in vitro analyses. Preliminary phytochemical profiling was performed to identify the bioactive constituents. Toxicity screening was also determined through brine shrimp lethality assay. Phytochemical screening revealed the presence of various chemical compounds with some identified phytoconstituents using GC-MS. Data indicated that methanol extract exhibited high DPPH scavenging ability and α-amylase inhibitory activity with IC50 values of 48.40 μg/ml and 127.56 μg/ml, respectively. Furthermore, higher total phenolics content was determined in the methanol extract than the aqueous extract. The results suggest that the bioactivity could be due to the synergistic effect of the active compounds, with emphasis on the phenolic compounds (phenols, flavonoids and tannins). The methanol fraction was also shown to have a weak cytotoxicity against brine shrimp. However, the aqueous extract prepared through decoction revealed to be non-toxic, thus supporting the safety of traditional preparation. The combined effects of α–amylase inhibitory and antioxidant activities of bark extract of T. orientalis may indicate a good antidiabetic potential of the plant.