In vitro antioxidant and anti-inflammatory activities of isolated compounds of ethanol extract from Sanchezia speciosa Leonard's leaves

Background Sanchezia speciosa has been used in traditional medicine for gastritis treatment in Vietnam. Some phytochemical study showed that S. speciosa contains high amounts of flavonoids and cardiac glycoside compounds. In the present study, we isolated four compounds from the ethanol extract of the S. speciosa leaf, and we evaluated the in vitro antioxidant and anti-inflammatory effect of the isolated compound from the ethanol extract of the S. speciosa leaf. Methods The leaf of S. speciosa Leonard was extracted with ethanol 96%. Compounds were isolated using column chromatography and identified by spectroscopic method, including IR, MS, and NMR and by comparing their physicochemical and spectral data with those published in literatures. These isolated compounds were investigated for their antioxidant activity using DPPH and inflammation inhibitory activity by inhibition of albumin denaturation assay. Results We have isolated four compounds quercetin 3-O-α-l-rhamnopyranosid (quercitrin) (1), quercetin 3-O-β-d-galactopyranosid (hyperosid) (2), sitosterol-3-O-β-D-glucopyranosid (daucosterol) (3), and 3-methyl-1H-benz[f]indole-4,9-dione (4) from the ethanolic extract of the S. speciosa leaf. The antioxidant activities were in the following order: compound 2>compound 1>compound 4>compound 3. The IC50 values of scavenging DPPH radicals for compound 2 was 20.83±1.29 μg/mL. For anti-inflammatory activities, the order was compound 4>compound 3>compound 2>compound 1. Compound 4 showed the strongest inhibition, with IC50 values of 193.70±5.24 µg/mL. Conclusions These compounds 1, 2, and 4 were isolated for the first time from the leaves of S. speciosa. These compounds showed strong antioxidant and anti-inflammatory activity.