Chemical Constituents Of Selaginella Tamariscina And Cryptocarya Depauperata And Their ?-Glucosidase Inhibitory Activities

Alpha-glucosidase can specifically hydrolyze alpha-glucosidic bonds to release glucose.It is an enzyme in the body responsible for hydrolyzing complex carbohydrates.Alpha-glucosidase mainly exists on the brush border of the human small intestine mucosa,and its main role is to promote the decomposition of carbohydrates such as starch,sucrose,and maltose in the human intestinal tract,thereby causing postprandial blood sugar to rise.Alpha-glucosidase inhibitors?AGIs?can prevent the decomposition of carbohydrates by inhibiting the binding of the mucosa in the upper segment of the small intestine brush border with alpha-glucosidase,which inhibits the production and absorption of glucose,so it can effectively reduce after blood sugar,it can prevent and treat diabetes.Alpha-glucosidase has become one of the important targets for the development of anti-diabetic drugs.For a long time,rich natural plant resources have been a huge treasure trove of drug research and development.Many anti-inflammatory,anti-viral,anti-tumor and other drugs that have been marketed now come from natural products and their derivatives.Therefore,it is of great significance to find safe and effective?-glucosidase inhibitors from natural products.Therefore,in order to find a highly effective?-glucosidase inhibitor derived from natural products,the subject has systematically studied the chemical composition and activity of two plants Selaginella tamariscina?Beauv.?Spring and Cryptocarya depauperata.The plants were extracted with 95%ethanol using the dipping method,and the resulting crude extract was fully suspended in water and extracted four times with petroleum ether and ethyl acetate,respectively.The obtained ethyl acetate phase was subjected to various separation methods such as MCI column chromatography,silica gel column chromatography,Sephadex LH-20 gel column chromatography,and reversed-phase semi-preparative HPLC.A total of 42 monomer compounds were separated,of which 11 were New compounds.The planar structure and absolute configuration of the new compound were determined using techniques such as nuclear magnetic resonance spectroscopy?NMR?,high-resolution mass spectrometry?HRMS?,optical measurement combined with CD spectroscopy,and calculated CD spectroscopy.Among them,seven compounds were isolated from S.tamariscina,including four neolignans?1*-3*and 4?,two alkynol compounds?5 and 6?,and one bisflavonoid compound?7?;Thirty-five monomeric compounds were isolated from C.depauperata,including 12?-pyrones?8-10,11*-17*,18 and 19?,five Lignans?20-24?,four amide alkaloids?25-28?,two simple aromatic compounds?29 and 30?,two indole compounds?31 and 32?,two stilbene Compounds?33 and 34?and eight flavonoids?35-41 and 42*?.In this thesis,12 polyketolactone compounds?8-19?isolated from the plant C.depauperata were tested for?-glucosidase activity inhibition.The results showed the compound 14 reveals the best inhibitory activity of?-glucosidase(IC₅₀ 8.09 mM),compound 15 also shows good inhibitory activity(IC₅₀ 13.04 mM),other compounds show moderate inhibitory activity,so the above compounds can be used as potential natural?-glucoside Enzyme inhibitors for further research and utilization.