ABSTRACT
The biologically active constituents in Gynostemma pentaphyllum are dammarane-type glycosides,called gypenosides.They are believed to be the highest contents of this herb,easy to obtain,and mainly active in anti-tumor,controlling the blood glucose,lipid-lowering,cardiovascular protection,etc.The saponins may change into sub-glucoside after hydrolysis,for the intemal acetal glucoside structure is vulnerable to acid,alkali,and enzyme degradation.Through searching the literatures in recent years,this paper summarized the chemical constituents in the hydrolyzed products of gypenosides,for providing references to discover novel and more active lead compounds.
ABSTRACT
Two γ-glutamyl-cysteine peptides (γ-GCPs ) , ( SC2 RC7 )-γ-L-glutamyl-S-allyl-L-cysteine ( 1 ) and ( SC2 RC7 )-γ-L-glutamyl-S-propyl-L-cysteine ( 2 ) have been isolated from fresh garlic scales using ion-exchange chromatography and pre-HPLC. Their molecular structures were identified by HPLC-MS, CD, 1 H NMR, 13 C NMR, specific rotation and confirmed by the corresponding standard compounds. The influence of exogenously adding 1 and 2 on the bioavailability of iron and zinc from food legume was examined with soybean and mung bean, in the level of 0. 01 mmol/5 g of legume respectively. The enhancing effect of the two γ-GCPs of compound 1 and 2 on bioaccessibility of iron was generally evidenced in the case of soybean ( from 1 . 88% to 6 . 73% and 4 . 42%) and mung bean ( from 2 . 52% to 12 . 04% and 9 . 38%) . The two γ-GCPs similarly enhanced the bioaccessibility of zinc from the food legume, in soybean ranging from 13. 37% to 23. 95% and 20. 58%, and in mung bean from 15. 98% to 28. 44% and 27. 05%. Thus, both compounds 1 and 2 obviously had a promoting influence on the bioavailability of iron and zinc from food legumes. These findings are of practical value in a food-based strategy to enhance the bioavailability of trace minerals for human health.