Chemical constituents from the seeds of Cassia obtusefolia and their in vitro α-glucosidase inhibitory and antioxidant activities.

Basing on chromatographic separation techniques, fifteen aglycones (1-15), including two new anthraquinone aglycones (1, 2) and thirteen known compounds (3-15), were isolated from the small polar fraction of Cassia obtusefolia (petroleum ether extract). Structural elucidations were performed by 1D/2D NMR spectroscopy and mass spectrometry. The in vitro antioxidant and α-glucosidase inhibitory activities of these fifteen compounds were determined. Except compounds 12 (IC50 3.03 ±â€¯0.31 µg/mL, stronger than ascorbic acid, which IC50 was 6.48 ±â€¯2.30 µg/mL) and 13 (IC50 78.40 ±â€¯2.39 µg/mL), the free radical scavenging capacities of other compounds were weak. Compounds 4, 5, 6 and 13 exhibited inhibitory activities on α-glucosidase with IC50 values of 50.60 ±â€¯1.10, 22.57 ±â€¯0.07, 60.09 ±â€¯1.40, and 80.01 ±â€¯2.66 µg/mL separately, however, all the α-glucosidase inhibitory activities were weaker than positive control (acarbose).

[Chemical study on Cassiae Semen processing procedure].

References and our previous experiment showed that the contents of glycosides were significantly decreased，while the contents of aglycones were significantly increased after processing of Cassiae Semen.It may be related to its glycosidases or the heating process. In order to investigate the reasons, high performance liquid chromatographic (HPLC) was used to study the effects of these two factors on contents of Cassiae Semen's main chemical components in processing. The results showed that glycoside hydrolases was present in Cassiae Semen and could rapidly hydrolyze glycosides from Cassiae Semen into aglycones in suitable temperature with sufficient water.However，it didn't show effect on contents change of main constituents in the procedure of Cassiae Semen processing.The reason for content decrease of glycosides and content increase of aglycones in processed Cassiae Semen was glycoside bond cracking to produce corresponding aglycone at high temperature.This study further provides basis for further revealing of the processing mechanism of Cassiae Semen.

[Chemical constituents from seeds of Astragali complanati].

A new flavonoid glycoside, named complanatoside C (1), and 19 known compounds (2-20) were isolated from an 95% ethanol extract of Astragali Semen by various chromatographic methods. Their structures were identified on the basis of UV, IR, NMR, MS spectroscopic data analysis, and comparison with those in literature, including fifteen flavonoid glycoside (1-15), and six other constituents (16-20), among which compounds 16-19 were isolated from this plant for the first time.