ACYLATED FLAVONOIDS OF SPIRAEA GENUS AS α-AMYLASE INHIBITORS

Abstract

Spiraea L. is a genus of deciduous shrubs of Rosaceae family widespread on the territory of Eastern Siberia. As a result of the study of six Spiraea species growing on the Baikal region, it was shown that they characterized by a high content of phenolic compounds and their extracts had an inhibitory effect on α-amylase. The use of correlation analysis made it possible to reveal the leading role of flavonoids as carriers of the biological effect of extracts. The most active was the extract of S. salicifolia leaves with an IC50 value 69,30 μg/mL After fractionation and chromatographic separation of the extractive substances, 18 compounds were isolated from the ethyl acetate fraction of S. salicifolia and fifteen of them for the first time for the species, including trifolin, 6′′-O-caffeoyl-hyperoside, 6′′-O-caffeoyl-isoquercitrin, 6′′-O-caffeoyl-astragalin, 1-O-p-hydroxybenzoyl-6-O-p-coumaroyl-β-d-glucopyranoside, 3,4,5-tri-O-caffeoylquinic acid, isoramnetinin-3-O-β-d-glucopyranoside, tiliroside, isoramnetin-3-O-α-l-rhamnopyranoside, 1-O-cis-cinnamoyl-6-O-(2′-methylene-4′-hydroxybutyroyl)-β-d-glucopyranose, 1-О-(4′′-hydroxy-3′′-methylfurane-2′′-one)-6-О-trans-cinnamoyl-β-d-glucopyranose, 1-О-(4′′-hydroxy-3′′-methylfurane-2′′-one)-6-О-cis-cinnamoyl-β-d-glucopyranose, 6-tuliposide A and tulipalin A. The most active inhibitors of α-amylase were flavonoid caffeoyl glycosides with 6′′-O-caffeoyl-hyperoside as a most effective inhibitor with IC50 value 46.18 μg/mL. Latter compound determined the total anti-α-amylase effect of S. salicifolia. The content of 6′′-O-caffeoyl-hyperoside in leaves of S. salicifolia was 0,60-10,53 mg/g and flavonoids – 12,02-23,17 mg/g. This study demonstrated the fact that the acylated flavonoids of Spiraea are effective inhibitors of α-amylase.