Steroidal glycosides from Tylophora ovata with anti-inflammatory and radical scavenging activities.

A chemical investigation on 80% ethanol extract from the whole plants of Tylophora ovata afforded two new C21 steroidal glycosides, ovatacosides A and B (1 and 2). Structural elucidation of both compounds were performed by spectral methods such as 1D and 2D (1H-1H COSY, HMQC, and HMBC) NMR spectroscopy and high resolution mass spectrometry. The isolated components were evaluated in vitro for anti-inflammatory activities against COX-1 and COX-2 and radical scavenging potential using DPPH test. Consequently, 1 exhibited modest selective inhibition on COX-1 (61.9%) at the concentration of 100 μM and significant DPPH scavenging activity (IC50 = 42.9 μM) comparable with positive control Trolox (IC50 = 44.2 μM).