ANTIOXIDANT, PTP 1B INHIBITION AND Α-AMYLASE INHIBITION PROPERTY AND GC-MS ANALYSIS OF METHANOLIC LEAVES EXTRACT OF ACHYRANTHES ASPERA AND CATHARANTHUS ROSEUS OF NEPAL

Objective: The present study was designed to study phytochemicals and biological activities of the methanolic extracts of two traditional medicine plants Achyranthes aspera and Catharanthus roseus of Nepalese origin. Methods: Plant extracts were prepared by cold percolation method. Antioxidant activity, brine shrimp lethality assay, and analysis of phytochemical constituents were carried out using standard methods. The dinitro salicylic acid (DNS) method was used to study the inhibition effect of extracts on α-amylase enzyme. Furthermore, PTP 1B inhibitory activity was evaluated using p-nitrophenyl phosphate (p-NPP) as substrate. Results: Phytochemical analysis showed the presence of phytochemicals like alkaloids, flavonoids, glycosides, reducing sugars, etc. in both plants. Brine shrimp lethality assay suggested the presence of pharmacologically active compounds. Total phenolic content and total flavonoid content of C. roseus were found to be higher with 73.21 mg GAE/g and 33.15 mg Q/g respectively than that of A. aspera, which was found to be 57.09 mg GAE/g and 28.96 mg Q/g respectively. Similarly, the α-amylase inhibition of A. aspera and C. roseus was found to be 97.60±1.11 µg/ml and 94.05±1.18 µg/ml comparative with IC50 68.13±0.46 µg/ml of standard acarbose. Protein tyrosine phosphatase 1B (PTP1B) inhibition showed IC50 for A. aspera and C. roseus to be 48.72±0.46 and 50.21±1.03 µg/ml, respectively. Qualitative GC-MS analysis of both plant hexane fractions showed acid and ester type of phytoconstituents. Conclusion: These results suggested that both plants i. e A. aspera and C. roseus, Nepal origin showed biological activity by targeting multiple drug targets which justifies their traditional uses.