RESUMEN
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.
RESUMEN
Objective: To screen potential α-glucosidase inhibitors from Anemarrhena asphodeloides. Methods: Response surface methodology employing Box-Behnken design was used to optimize conditions for the extraction of α-glucosidase inhibitory active compounds from A. asphodeloides. The powders (20.0 g) of A. asphodeloides were extracted under the optimized conditions. The extract was applied to a D-101 macroporous resin column. It was eluted with ethanol and water to give six fractions. Compounds from the active fraction were identified by UPLC-Q-TOF-MS. The structure-activity relationship was discussed based on grey relational analysis. Results: The optimum extraction conditions were as follows: ethanol concentration, 100%; extraction temperature, 51 °C; and solvent to solid ratio, 23 mL/g. It indicated that the active compounds were concentrated into 80% ethanol fraction. Twenty five steroid saponins from 80% ethanol fraction were identified by UPLC-Q-TOF-MS. Peaks 19 and 23 were tentatively identified as new structures. The predicted α-glucosidase inhibitory activities of the compounds were 7 > 2 > 1 > 22 > 23 > 3 > 9 > 21 > 24 > 4 > 13 > 8 > 14 > 16 > 17 > 25 > 6 > 19. Conclusion: The fraction eluted by 80% ethanol showed the best inhibitory activity. After analyzing the data of UPLC-Q-TOF-MS, 25 steroid saponins were tentatively identified in this fraction.