RESUMO
Objective: To study the chemical constituents from the leaves of Platycladus orientalis, as well as their antioxidant and α-glucosidase inhibitory activities. Methods: The compounds were isolated and purified by silica gel, MCI, polyamide, and prep-HPLC chromatography, their structures were elucidated by spectral analysis. DPPH and ABTS methods were used to study the antioxidant activity, and pNPG method was used to study the α-glucosidase inhibitory activity. Results: Eleven compounds (1-11) were isolated from the 80% ethanol extract of the leaves of P. orientalis, and identified as 4-O-(1’,3’-dihydroxypropan-2’-yl)- dihydroconiferyl alcohol 9-O-β-D-glucopyranoside (1), myricetrin (2), 5,8,3’,4’-tetrahydroxy-flavone-7-O-β-D-xylopyranoside (3), isomassonianoside B (4), (-)-isopramine 9’-O-β-D-glucopyranoside (5), (7R,8S,7’S,8’R)-4,9,4’,7’-tetrahydroxy-3,3’-dimethoxy- 7,9’-epoxylignan 4-O-β-D-glucopyranoside (6), sugiol (7), totarol (8), 5,6-dehydrosugiol methyl ether (9), isopimara-8,15-dien-7-one (10) and ethanol α-L-rhamnopyranoside (11). Conclusion: Compound 1 is a new compound, named as platycloside A; In the known compounds, seven compounds (4-7, 9-11) are isolated from this plant for the first time, six compounds (4-6, 9-11) are isolated from the family Thujoideae for the first time, and four compounds (5, 6, 10, 11) are isolated from the family Cupresaceae for the first time. The compounds 2-6 showed a degree of antioxidant activities. The compounds 2 and 3 showed the α-glucosidase inhibitory activities.