Sesquiterpenes and an intermediate 1alpha, 6beta, 11-eudesmanetriol in the biosynthesis of geosmin from Streptomyces sp / 药学学报

One new sesquiterpene was isolated from the fermentation broth of Streptomyces sp. and the structure was elucidated by spectral analysis as caryolane-1, 6beta-diol (1). An intermediate 1alpha, 6beta, 11-eudesmanetriol (2) in the biosynthesis of geosmin was also found in this strain which proved sequence for the reactions, especially bicyclization preceding dealkylation.

Three cyclic dipeptides from the root of Psammosilene tunicoides / 中国中药杂志

<p><b>OBJECTIVE</b>[corrected] To study the cyclic peptides from Psammosilene tunicoides.</p><p><b>METHOD</b>The constituents were separated and purified with chromatographic methods, identified by NMR, MS, UV and IR.</p><p><b>RESULT</b>Three cyclic dipeptides: cyclo(-Pro-Val-) (1), cyclo(-Pro-Ala-) (2) and cyclo(-Pro-Pro-) (3), were isolated and identified.</p><p><b>CONCLUSION</b>Compound 1 and 2 are new natural products, compound 3 was isolated for the first time from Psammosilene tunicoides.</p>