In vitro anti-inflammatory and xanthine oxidase inhibitory activity of Tephrosia purpurea shoot extract

The methanolic extract of Tephrosia purpurea (Leguminosae) shoots was evaluated in-vitro for its anti-inflammatory and xanthine oxidase inhibitory activity. Anti-inflammatory activity was measured by the Diene-conjugate, HET-CAM and beta-glucuronidase methods. The enzyme inhibitory activity was tested against isolated cow milk xanthine oxidase. The average anti-inflammatory activity of T. purpurea shoot extract in the concentration range of 1-2 microg/mL in the reacting system revealed significant anti-inflammatory activities, which, as recorded by the Diene-conjugate, HET-CAM and beta-glucuronidase assay methods, were 45.4, 10.5, and 70.5%, respectively. Screening of the xanthine oxidase inhibitory activity of the extract in terms of kinetic parameters revealed a mixed type of inhibition, wherein the Km and Vmax values in the presence of 25 to 100 microg/mL shoot extract was 0.20 mM/mL and 0.035, 0.026, 0.023 and 0.020 microg/min, while, for the positive control, the Km and Vmax values were 0.21 mM/mL and 0.043 microg/min, respectively. These findings suggest that T. purpurea shoot extract may possess constituents with good medicinal properties that could be exploited to treat the diseases associated with oxidative stress, xanthine oxidase enzyme activity and inflammation.