Hygromycin A derivatives isolated from Streptomyces sp. PC-22 in the rhizosphere soil of Pulsatilla chinensis.

On the basis of the one strain-many compounds (OSMAC) strategy, two new hygromycin A derivatives (3, 4), together with six known compounds were isolated from a medicinal plant inter rhizospheric Streptomyces in Pulsatilla chinensis. The structures of 3 and 4 were elucidated using NMR and HRESIMS analyses. A plausible biosynthetic pathway for these compounds was discussed. All the compounds were evaluated for their antimicrobial and cytotoxic activities. Compound 5 exhibited potent inhibitory activity against S. aureus and B. subtilis with the MICs of 16 and 8 µg ml-1, while 4 showed weak inhibitory activity against S. aureus.

Four new hybrid polyketide-terpenoid metabolites from the Penicillium sp. SYPF7381 in the rhizosphere soil of Pulsatilla chinensis.

A search for cytotoxic agents from cultures of the Penicillium sp., isolated from the rhizosphere soil of Pulsatilla chinensis, led to the isolation of four new hybrid polyketide-terpenoid metabolites (1-4), together with fourteen known compounds (5-18). Using a bioassay-guided fractionation approach, eighteen compounds were obtained from the ethyl acetate extract of this fungus. Structure elucidation was achieved by extensive analysis of spectroscopic data (1D/2D NMR, HRESIMS and IR). The absolute configurations of compounds 1-4 were determined by means of electronic circular dichroism (ECD) calculation. Compounds 1-4, 7-9, 11, 12, 14 and 17 were tested for their cytotoxicity against HL-60, THP-1 and Caco2 cell lines. Compound 1 showed potent cytotoxic capability against HL-60, THP-1 and Caco2 cell with IC50 values of 3.4µM, 4.3µM, 10.5µM, and compound 2 showed significant inhibiting activities against HL-60 cell line and THP-1 cell line (IC50=7.9µM, 11.3µM, respectively), using 5-fluorouracil as the positive drug with IC50 values of 6.4µM, 4.4µM, 56.6µM for HL-60, THP-1 and Caco2 cells, respectively. And compound 1 showed antibacterial activity toward Bacillus cereus (IC50=49µg/mL, IC90=111µg/mL) and Bacillus subtilis (IC50=10µg/mL, IC90=85µg/mL).

[Genetic diversity of Ascochyta anemones isolates in Liaoning Province of Northeast China].

Windflower leaf spot is a newly reported leaf disease in China, and becomes very serious in the protected field of windflower (Pulsitilla chinensis) in Liaoning Province. In this study, a random amplified polymorphic DNA (RAPD) analysis was made on the 25 Ascochyta anemones isolates from 5 main P. chinensis production areas in the Province and 5 Ascochyta spp. isolates presented by the Chinese Academy of Agricultural Sciences. A total of 108 polymorphic DNA bands sized 200-2000 bp were obtained by using 11 random primers. The NTSYS cluster analysis showed that the genetic similarity coefficient of the 30 Ascochyta isolates was 0.56-0.98, and these isolates could be divided into 4 genetic groups when the similarity coefficient was 0.62, suggesting that the pathogens of windflower leaf spot in the Province had rich genetic diversity. There existed definite correlations between the RAPD clustering groups and their geographic distribution, and an obvious genetic difference among the isolates from different host sources.