Three new diterpenoids, 2-O-lactoylborapetoside B (1), 6'-O-lactoylborapetoside B (2), and tinocrispol A (3), and nine known diterpenoids (4-12) were isolated from an EtOH extract of Tinospora crispa vines. Their structures were elucidated by spectroscopic analyses. The C-6 glucosyloxy group in borapetoside C (6) was revised to be α-oriented. The in vivo hypoglycemic activities of the major components, borapetosides A-C (4-6), were examined. Intraperitoneal injection of 4 and 6 (5 mg/kg) showed significant lowering of plasma glucose levels in normal and streptozotocin-induced type 1 diabetic mice. Borapetoside C increased glucose utilization in peripheral tissues and reduced hepatic gluconeogenesis, accounting for the hypoglycemic effect.
Eight compounds, including two flavonoid glycosides, were isolated from the butanol-soluble fraction of the methanolic extract of the leaves of Phyllanthus reticulatus by conventional methods. A polyphenol rich fraction, obtained by Sephadex LH-20 fractionation, was also studied using an HPLC-SPE-NMR technique leading to the characterization of six compounds including three additional flavonoid glycosides. The latter approach used only 1 mg of samples, theoretically equivalent to 0.3 g of dry leaves. This study demonstrates that HPLC-SPE-NMR is very useful for thorough chemical investigation and also offers the advantages of saving time, plant materials and consumables over more conventional methods.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.