Lysohexaenetides A and B, linear lipopeptides from Lysobacter sp. DSM 3655 identified by heterologous expression in Streptomyces / 中国天然药物

Lysobacter harbors a plethora of cryptic biosynthetic gene clusters (BGCs), albeit only a limited number have been analyzed to date. In this study, we described the activation of a cryptic polyketide synthase (PKS)/nonribosomal peptide synthetase (NRPS) gene cluster (lsh) in Lysobacter sp. DSM 3655 through promoter engineering and heterologous expression in Streptomyces sp. S001. As a result of this methodology, we were able to isolate two novel linear lipopeptides, lysohexaenetides A (1) and B (2), from the recombinant strain S001-lsh. Furthermore, we proposed the biosynthetic pathway for lysohexaenetides and identified LshA as another example of entirely iterative bacterial PKSs. This study highlights the potential of heterologous expression systems in uncovering cryptic biosynthetic pathways in Lysobacter genomes, particularly in the absence of genetic manipulation tools.

A study on anti-inflammatory and analgesic effects of alkaloids of Toddalia asiatica / 中西医结合学报

OBJECTIVE: To study the pharmacological activities and toxicity of the crude alkaloids of Toddalia asiatica and to provide pharmacological data for the further development of this herbal medicine. METHODS: We observed the anti-inflammatory effects of the crude alkaloids of Toddalia asiatica, using xylol and agra to induce the turgidness and sodium carboxymethyl cellulose (CMC-Na) to induce leucocyte strolling in the rats. The analgesic effects were observed by body-distortion methods. The effects of alkaloids of Toddalia asiatica on hepatic function were observed by testing the contents of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in serum and calculating the liver index. The LD 50 and 95% creditability were calculated with developed Karber Method. RESULTS: The administration of alkaloids of Toddalia asiatica had the function of inhibiting the auricle swelling caused by xylol and joint swelling caused by agar and leucocyte migration caused by CMC-Na, decreasing the body-distortion of the rats. After two weeks administration, the contents of ALT and AST showed that there was no obvious difference between administered group and control group. The LD50 of the crude alkaloids of Toddalia asiatica was 1.622 g/kg and the 95% creditability was 1.29-2.03 g/kg. CONCLUSION: Toddalia asiatica has anti-inflammatory and analgesic effects, and there is no injury to the liver after long-term administration in rats.

Studies on chemical constituents of Callicarpa pedunculata / 中草药

Object To study the chemical constituents of whole plant of Callicarpa pedunculata R Brown Methods Various chromatographic techniques were employed for isolation and purification of its constituents; and their structures were identified by spectral analysis (IR, MS, 1HNMR, 13 CNMR) and chemical evidences Results Ten compounds were obtained from the chloroform extract of the whole plant Among them four were diterpenoids which were identified as: 14 ?-hydroxy-7, 15-isopimaradien-18-oic acid (Ⅰ), 16 ?, 17-dihydroxy-3-oxo-phyllocladanetriol (Ⅱ), 8, 11, 13, 15-abietetraen-18-oic acid (Ⅲ), and 6 ?-hydroxy nidorellol (Ⅳ); 2 flavonoids: 5-hydroxy-3, 4′, 7-trimethoxy-flavone (Ⅴ), and 3, 5-dimethyl kaempherol (Ⅵ); and the others were ursolic acid (Ⅶ), myoinositol (Ⅷ), ?-sitosterol (Ⅸ), and ?-amyrin (Ⅹ) Conclusion Compounds Ⅰ, Ⅱ, Ⅲ, Ⅳ were found in this plant for the first time and it was of interest to note that they were of different diterpenoid skeletons The content of ursolic acid attained to a high level up to 1%, which may be exploited as a natural resource for medical purposes