Flavonoids glycosides from Camellia phanii

Abstract

By combining chromatography methods, three new flavonoid glycosides, kaempferol 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl-(1→2)-α-L-rhamnopyranoside (1), kaempferol 3-O-(4-acetyl)-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl-(1→2)-α-L-rhamnopyranoside (2), and (2 R,3 S) 5,7,4′-tetrahydroxyflavanonol 3-O-(4-acetyl)-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl-(1→2)-α-L-rhamnopyranoside (3) as well as three known compounds, chrysandroside A (4), p-hydroxybenzaldehyde (5), and p-hydroxybenzoic acid (6) were isolated from the leaves of Camellia phanii Hakoda & Ninh. Their structure was elucidated by 1D and 2D-NMR spectra and compared to previously published in literature. In addition, all compounds were evaluated for their ability to inhibit α-glucosidase activity. As the results, flavonoid glycosides 1-3 inhibited α-glucosidase activity with IC₅₀ values of 276.8 ± 19.4, 258.9 ± 24.3, and 341.4 ± 25.6 µM; phenolics (5 and 6) inhibited α-glucosidase activity with IC₅₀ values of 295.5 ± 15.1 and 217.4 ± 23.6 µM, respectively.