Abstract:
Background: Pancreatic α-amylase inhibitors offer an effective strategy to reduce postprandial
hyperglycemia in the management of diabetes mellitus. In this study, two medicinal plants;
Trianthema decandra and Thespesia populnea were subjected to determine the α- amylase
inhibitory activity. Though the alpha amylase activity of these above-mentioned plants has been
investigated in different countries, the level of alpha amylase activity presence in these plants has
not been investigated so far in Sri Lanka.
Objective: To determine the in vitro alpha amylase inhibitory activity of T.decandra and
T.populnea leaves extracts using porcine pancreatic α- amylase enzyme.
Methods & Materials: The leaves of T.decandra and T.populnea were collected from Jaffna,
dried under shade, ground to a powder. The extractions were prepared by maceration with
methanol, acetone and petroleum ether. Subsequently, α-amylase inhibitory assay was performed
separately on the leaf extracts of T. decandra and T. populnea by employing acarbose as the
standard compound. The IC50 values for the extracts were calculated from the respective assay.
The statistical significance was evaluated by the analysis of variance (ANOVA) followed by
Tukey’s test.
Results: The IC50 values of leaf of methanol, acetone, petroleum ether extracts were 44.34±2.3
μg/ml, 346.6±4.5 μg/ml, 674.9±2.7μg/ml. Methanol, acetone and petroleum ether leaf extracts of
T. decandra showed IC50 values of 175.93±4.04 μg/ml, 447.6±1.3 μg/ml, and 1020.3±3.2 μg/ml.
The methanol extract of T. populnea showed significantly α-amylase inhibition comparable to the
acarbose (IC50 = 83.85±2.64 μg/ml) (p>0.05). None of the petroleum ether extracts showed alpha
amylase inhibitory activity.
Conclusion: The findings revealed that methanolic extract of T.populnea leaf extract exhibited
α – amylase inhibitory activity which could be used for further screening of specific bioactive
compounds that might responsible for their α amylase inhibitory activity.
