Genome-based analysis of the type II PKS biosynthesis pathway of xanthones in Streptomyces caelestis and their antifungal activity.

The ethyl acetate extract from the liquid fermentation of S. caelestis Aw99c exhibited high and broad antifungal activities against plant pathogenic fungi. Bioassay guide fractionation led to the discovery of two xanthones, citreamicin ε and θ. The draft genome sequence of S. caelestis Aw99c was analyzed by a similarity-based approach to elucidate the pathway for the citreamicins. A 48 kb citreamicin (cit) gene cluster with 51 open reading frames encoding type II polyketide synthases and unique polyketide tailoring enzymes was proposed based on the genome analysis and the chemical structure derivation. In vitro antifungal assay showed that citreamicin ε exhibited significant growth inhibition against the plant pathogenic fungi with MIC values ranging from 1.56 to 12.5 µM. The cellular structural change of M. grisea treated with citreamicin ε was detected by SEM and the result showed that citreamicin ε caused disruptive surface of the mycelia.

Simultaneous determination of calycosin-7-O-ß-D-glucoside, ononin, calycosin, formononetin, astragaloside IV, and astragaloside II in rat plasma after oral administration of Radix Astragali extraction for their pharmacokinetic studies by ultra-pressure liquid chromatography with tandem mass spectrometry.

A sensitive and reliable ultra-pressure liquid chromatography with tandem mass spectrometry (UPLC-MS) was developed and validated for simultaneous quantification of six main bioactive components, i.e., calycosin-7-O-ß-D-glucoside, ononin, calycosin, formononetin, astragaloside IV, and astragaloside II in rat plasma after oral administration of the 95 % ethanol extraction from Radix Astragali. Plasma samples were extracted with Waters Oasis(TM) HLB 1 cc (30 mg) Extraction Cartridges (SPE) separated on an UPLC™ BEH C18 column and detected by MS with electro spray ionization interface in positive selective ion monitoring mode. Calibration curves offered linear ranges of two orders of magnitude with r (2) > 0.99. The method had the lower limit quantification of 1.30, 0.73, 1.17, 2.33, 0.63, and 0.83 ng/mL for ononin, calycosin, calycosin-7-O-ß-D-glucoside, formononetin, astragaloside IV, and astragaloside II, respectively, with precision less than 10 %. The RSD of intra- and inter-day variations ranged from 1.66 to 6.46 and 3.39 to 6.58 %. This developed method was applied subsequently to pharmacokinetic studies of the six compounds in rats successfully. The proposed method was for the first time to compare the pharmacokinetic difference between calycosin-7-O-ß-D-glucoside and calycosin in rat plasma, so as between ononin and formononetin, and studied to the astragaloside II pharmacokinetics in rat plasma.

[Research on relevance between macroscopic feature individual differences and quality of Gansu cultivated Angelica sinensis].

OBJECTIVE: To analyze the appearance differences of Gansu cultivated Angelica sinensis, and explore the relevance between the appearance differences and quality. METHODS: The macroscopic feature of 22 batches of Angelica sinensis from different habitats was measured as index. The content of ferulic acid, volatile oil and extract were determined by the method recorded in the Chinese Pharmacopoeia. The data were analyzed by SPSS 15.0 software. RESULTS: The habitat was positively correlated with the index. Indexes of nine groups had direct correlation with each other. The habitat was significantly correlated with other indexes except the length of the head. The extract and ferulic acid were positively correlated with habitat and index. Extract had significant correlation with macroscopic feature. Ferulic acid only had significant correlation with head length. The volatile oil only had significant correlation with habitat and no significant correlation with index. Root weight and number of lateral roots had obvious difference in different habitat which coefficient of variation was 44.1% and 28.6%, respectively. CONCLUSION: There are significant individual differences in Angelica sinensis. The chemical composition has a certain correlation with macroscopic feature. Angelica sinensis cultivation needs to consider the choice of habitat.