Phytochemistry, antioxidant capacity, total phenolic content and anti-inflammatory activity of Hibiscus sabdariffa leaves

A liquid chromatography-mass spectrometry method was developed for the simultaneous separation, and determination of natural compounds including phenolic acids and flavonoids in the leaves of Hibiscus sabdariffa. By analyzing the UV and MS data, and comparison with authenticated standards, 10 polyphenols including neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, quercetin, kaempferol and their glycosides were identified together with 5-(hydroxymethyl)furfural. Major constituents in the leaves of 25 different populations from worldwide accessions were quantified and compared with each other. The total phenolic content of each accession was determined using Folin-Ciocalteu assay, ranging from 18.98 ± 2.7 to 29.9 ± 0.5 mg GAE/g. Their in vitro antioxidant activities were measured by ABTS radical cation decolorization assay, varying from 17.5 to 152.5 ± 18.8 μmol Trolox/g. After the treatment of H. sabdariffa leaf extract, the reduction of LPS-induced NO production dose-dependently in RAW 264.7 cell indicates the extract's potential anti-inflammatory activity.