The Chemical Constituents from Punica granatum Peels

PurposeTo study the chemical constituents and their anti-complement activity from pomegranate (Punica granatum L.) peels.

MethodsCompounds were isolated and purified by column chromatography of silica gel, Sephadex LH-20 gel and RP-C18. And their structures were identified by spectral methods (MS and NMR). The anti-complement activity was determined by the hemolysis method of the complement classical pathway.

ResultsFourteen compounds were isolated and identified from the ethyl acetate and n-butanol fractions of the pomegranate peel ethanol extracts, including five flavonoid glycosides, kaempferol-3-O-β-d-glucopyranoside (1), quercetin-3-O-β-d-glucopyranoside (2), kaempferol-3-O-β-d-xylopyranoside (3), naringenin-7-O-β-d-glucopyranoside (4), and kaempferol-3-O-β-d-rutinoside (5), and nine other types of compounds, 5-hydroxymethylfurfural (6), n-butyl-O-β-d-fructopyranoside (7), 3, 3′-di-O-methylellagic acid 4-O-β-d-glucopyranose (8), roseoside (9), 3-O-(β-d-glucopyranosyl)-1-(3-methoxy-4-hydroxyphenyl)-1-propanone (10), 3-O-(β-d-glucopyranosyl)-1-(3, 5-dimethoxy-4-hydroxyphenyl)-1-propanone (11), 5-hydroxymethylfuran-3-carboxylic acid (12), (1′R, 3′S, 5′R, 8′S, 2Z, 4E)-dihydrophaseic acid 3′-O-β-d-glucopyranoside (13), and gallic acid (14). The ethyl acetate-soluble fraction possessed anti-complement activity with an inhibition rate of 51.73% at 100 μg/mL.

ConclusionCompounds 3, 4, 7, and 9-13 were isolated from this plant for the first time. The ethyl acetate-soluble fraction had anti-complement activity, however, the active components need to be further clarified. This research enriched the chemical constituents of P. granatum and provided experimental evidences for further exploitation and utilization of medicinal value from pomegranate peels.