One new diketopiperazine alkaloid amauromine B (1), along with three known meroterpenoids, austalide B (2), austalides N and O (3 and 4), and two known steroids (5 and 6), was isolated and identified from the culture broth of the fungus Aspergillus terreus 3.05358. Their structures were elucidated by extensive spectroscopic techniques, including 2D-NMR and MS analysis, the absolute configuration of 1 was unambiguously established by single crystal X-ray diffraction analysis. All the isolates were evaluated for their inhibitory effects on α-glucosidase. Amauromine B (1) and austalide N (3) exhibited more potent α-glucosidase inhibitory activities than the positive control acarbose.

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Two new C21 steroidal glycosides named as cynotophyllosides K-L, were isolated from the roots of Cynanchum otophyllum, together with three known steroids cynotophylloside H, sarcostin and deacetylmetaplexigenim. The structure of the new compounds were established by spectroscopic and chemical analyses, especially 2D NMR techniques.

Two new steroidal glycosides, cynotophyllosides K (I) and L (II), are isolated from the roots of Cynanchum otophyllum together with three known steroids.