Flavonol glycosides with lipid accumulation inhibitory activity and simultaneous quantitative analysis of 15 polyphenols and caffeine in the flower buds of Camellia sinensis from different regions by LCMS

A simultaneous quantitative analytical method for 15 major polyphenols, e.g. five catechins (1–5) and 10 flavonols (6–15), as functional constituents in the extracts of “tea flowers”, the flower buds of Camellia sinensis (Theaceae), has been developed. The content of caffeine (16), which showed similar chromatographic behaviour under the analytical conditions, was also determined. To approve the validity of the newly developed protocol, thirteen extracts of the plant’s flower buds collected from different regions, i.e. China, Taiwan, Japan and India, were evaluated. The results indicated that the assay was reproducible and precise, and could be readily underutilised for the quality evaluation of tea flowers on the basis of polyphenols’ contents. It was noteworthy that the contents of two major constituents, kaempferol 3-O-β-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (10) and kaempferol 3-O-β-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→6)-β-d-galactopyranoside (11), varied by region where the flower buds were produced. A new flavonol glycoside, chakaflavonoside B (17), which was isolated in the course of this analytical study, was found to show oleic acid-albumin-induced lipid accumulation inhibitory activity.