In-Vitro α-amylase Inhibitory and Anti-oxidant activities of Leaf Extract of Vitex trifolia L.

Monapati Suchitra¹, Binoy Varghese Cheriyan*^2
1Research Scholar, Department of Pharmaceutical Chemistry and Analysis, School of Pharmaceutical Sciences, VelsInstitute of Science, Technology and Advanced Studies (VISTAS), Pallavaram, Chennai – 600 117, Tamil Nadu, India.
²Department of Pharmaceutical Chemistry and Analysis, School of Pharmaceutical Sciences, Vels Institute of Science, Technology and Advanced Studies (VISTAS), Pallavaram, Chennai – 600 117, Tamil Nadu, India.

A B S T R A C T
Lifestyle and stress play a major role in diabetic physiology. Natural antioxidants exist as therapeutic tools. Vitex trifolia L. is a flowering shrub indigenous to temperate regions. Aim and objective of the present work are to identify the potential of in vitro inhibitory activity of a α-amylase enzyme and antioxidant activity of leaf extract of Vitex trifolia L. Shade-dried finely powdered leaves of Vitex trifoliaL. were extracted with organic solvents of increasing polarity such as n-hexane, ethyl acetate, and ethanol 95%. The extract was subjected to phytochemical screening, quantitative estimation of total phenols, flavonoids and tannins. Antioxidant activity by DPPH, hydroxyl, nitric oxide, and hydrogen peroxide radicals were carried out for the extract. Different concentrations of the extracts were subjected to α-amylase inhibitory activity using soluble starch as substrate and the IC ₅₀ value was calculated.  Phytochemical screening revealed the presence of phytoconstituents like phenols, flavonoids, alkaloids, terpenoids, glycosides, saponins etc. The ethanolic fraction of the leaf extract exhibited the highest antioxidant activity for DPPH, hydroxy, nitric oxide and hydrogen peroxide radical methods with the IC₅₀ values of 50.41, 50.14,49.64and 56.47µg/mL respectively compared to IC₅₀ value of standard ascorbic acid. Almost all extracts have shown good α-amylase inhibitory activity but ethanolic extract exhibited significant activity with an IC ₅₀ value of48.74µg/mL when compared with acarbose IC₅₀ value of 48.25µg/mL. Furthermore, the result showed high levels of phenolic, flavonoid, and tannins content. Statistical analysis using Graph pad prism version 8.4.2(649) showed a significant correlation. This is the first time reporting antidiabetic activity of this species. The uniqueness of the work lies in proving the antioxidant and anti diabetic activities of the extract of Vitex trifolia L. which has got commercial and societal values.
Keywords: Anti diabetic activity; ethanolic fraction; IC₅₀ value, porcine pancreatic amylase and Vitex trifolia L.