ABSTRACT
The compounds in leaf and stem extracts of Astragalus emarginatus Labill.(AEL),a plant species used in traditional Lebanese medicine,were investigated for antioxidant properties.First,the activity of various extracts was assessed using the Trolox equivalent antioxidant capacity,oxygen radical absorption ca-pacity,and 2,2-diphenyl-1-picryl-hydrazy l-hydrate assays.The extract obtained using 30％ethanol showed the greatest activity.The antioxidant compounds in this extract were screened using a hy-phenated high-performance liquid chromatography-2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonate)radical(ABTS+)system before being separated by ultra-high-performance liquid chromatography and identified using high-resolution mass spectrometry and ultra-violet-visible diode array detection.Approximately 40 compounds were identified.Hydroxycinnamates(caffeic,ferulic,and p-coumaric acid derivatives)and flavonoids(quercetin,luteolin,apigenin,and isorhamnetin derivatives)were the two main categories of the identified compounds.The active compounds were identified as caffeic acid de-rivatives and quercetin glycosides.In addition,the catechol moiety was shown to be key to antioxidant activity.This study showed that AEL is a source of natural antioxidants,which may explain its medicinal use.
ABSTRACT
Abstract Shenqu is a fermented product that is widely used in traditional Chinese medicine (TCM) to treat indigestion; however, the microbial strains in the fermentation process are still unknown. The aim of this study was to investigate microbial diversity in Shenqu using different fermentation time periods. DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) profiles indicated that a strain of Pediococcus acidilactici (band 9) is the predominant bacteria during fermentation and that the predominant fungi were uncultured Rhizopus, Aspergillus oryzae, and Rhizopus oryzae. In addition, pathogenic bacteria, such as Enterobacter cloacae, Klebsiella oxytoca, Erwinia billingiae, and Pantoea vagan were detected in Shenqu. DGGE analysis showed that bacterial and fungal diversity declined over the course of fermentation. This determination of the predominant bacterial and fungal strains responsible for fermentation may contribute to further Shenqu research, such as optimization of the fermentation process.