RESUMO
Butyrate-producing bacteria are specific intestinal bacteria with butyrate as the main metabolite, and most of them are Firmicutes.Butyrate-producing bacteria can synthesize butyrate with non-digestible carbohydrates in the diet, and then regulate intestinal microecology and microenvironment, thereby supplying energy to intestinal epithelial cells, affecting intestinal mucosal barrier, adjusting intestinal flora structure and regulating host immunity, so as to alleviate obesity, hypertension and other diseases.Therefore, the targeted regulation of butyrate-producing bacteria and butyrate has become a potential vital method for the prevention and treatment of many diseases.After oral administration, Chinese herbal medicine (CHM) enters the body, and first contacts gastrointestinal tract, so the interaction between CHM and microbiota existing in the intestine is an inevitable important process.It has been confirmed that CHM could regulate intestinal flora; and due to its complex composition and numerous components, CHM can exert interventional effects at multiple levels, in multiple pathways and on multiple targets.Its effect on the butyrate-producing bacteria is as follows.In the intestinal tract, CHM can play a " prebiotic" role, and enrich the beneficial butyrate-producing bacteria, and polysaccharides in CHM can be used as a fermentation substrate to promote the synthesis of butyrate, so as to achieve the effective regulation of butyrate-producing bacteria and butyrate.Based on that, this paper explored the relationship among butyrate-producing bacteria, butyrate and intestinal microecology, and reviewed relevant researches about the intervention of CHM on butyrate-producing bacteria to regulate intestinal microecology in recent years, in order to provide new research ideas for the application of CHM to prevent and treat diseases, as well as drug development.
RESUMO
A simple and convenient procedure for stereoselective synthesis of (Z)-allyl selenides has been developed by a one-pot reaction of diselenides with Baylis-Hillman adducts in the presence of samarium metal-trimethylsilyl chloride under mild conditions. Presumably, the diselenides are cleaved by Sm/TMSCl system to form selenide anions, which then undergo S(N)2' substitution of Baylis-Hillman adducts to produce the (Z)-allyl selenides.
Assuntos
Espectroscopia de Ressonância Magnética , Estrutura Molecular , Compostos Organosselênicos , Química , Compostos de Selênio , Química , EstereoisomerismoRESUMO
Stereoselective transformation of Baylis-Hillman acetates 1 into corresponding (Z)-allyl iodides 2 has been achieved by treatment of 1 with samarium triiodide in THF. Remarkable rate acceleration of samarium triiodide-mediated iodination of 1 was found when ionic liquid 1-n-butyl-3-methyl-imidazolium tetrafluroborate ([bmim]BF(4)) was used as reaction media in stead of THF. This novel approach proceeds readily at 50 degrees C within a few minutes to afford (Z)-allyl iodides 2 in excellent yields. A mechanism involving stereoselective iodination of the acetates of Baylis-Hillman adducts by samarium triiodide is described, in which a six-membered ring transition state played a key role in the stereoselective formation of 2.