Exploration of in vitro antioxidant, thrombolytic activity, neuropharmacological and anti-pyretic activity of leaf extracts of hoya parasitica (wall.)

The objective of the present study was to investigate the in vitro phytochemical screenings, thrombolytic, antioxidant, in vivo neuropharmacological and anti-pyretic activity of leaf extracts of Hoya parasitica Wall. Preliminary phytochemical screening was done for determining the nature of phytoconstituents or bioactive constitutes, which were assessed for their possible clot lysis, antioxidant, neuropharmacological and anti-pyretic activities as compared with the known drugs. Different classes of phytochemicals were present in the leaf extract. The methanol extract exhibited highest percentage of clot lysis (14.67%) as compared to 28.26% clot lysis produced by standard streptokinase. Among the three extracts, methanol and ethanol extracts showed relatively better cupric reducing antioxidant capacity with IC50 value (61.15 µg/ml) and satisfactory antioxidant potential in hydrogen peroxide scavenging assay with IC50 value (61.48 µg/ml) in comparison with L-ascorbic acid. Chloroform extract of H. parasitica was found to possess the highest total antioxidant capacity (1.86 mg/gm). Ethanol and chloroform extracts (100 and 200 mg/kg body weight) and methanol extracts (200mg/kg body weight) shortened the immobility period significantly (**p<0.01; ***p<0.001) in comparison with standard. In open field teat, ethanol extracts (100 & 200 mg/kg body weight) significantly (**P<0.01) decreased the rate of movement with time in a dose dependent manner. Significant (*p<0.05) antipyretic activity was observed by methanol and chloroform extracts in a dose dependent manner compared to standard. It can be concluded from the plant extracts of H. parasitica have significant thrombolytic, antioxidant, neuropharmacological and antipyretic activity which justifies its use as traditional medicine.