Phytochemical and biological properties of four Astragalus species commonly used in traditional Palestinian medicine

Abstract

IntroductionSeveral species that belong to the genus Astragalus have been used in Palestinian folk medicine to treat various infectious and non-infectious diseases. This study aimed to assess the phytochemical and biological activities of four Astragalus species growing wild in Jerusalem. MethodsPhytochemical screening, estimation of total phenols, flavonoids and tannin contents, as well as antimicrobial and antioxidant activities were investigated for Astragalus aleppicus, Astragalus angustifolius, Astragalus annularis, and Astragalus boeticus. Phytochemical screening, evaluation of total phenols, flavonoids, tannins contents as well as antioxidant properties were investigated by using standard phytochemical methods. Detection of antimicrobial activities for both the aqueous and the methanolic extracts were performed using the broth micro-dilution method. The antimicrobial activities were examined against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa American Type Culture Collection reference strains, as well as against Methicillin Resistant Staphylococcus aureus and Candida albicans clinical isolates. ResultsA mixture of phytochemical compounds was found in the extracts of all tested Astragalus species. A. boeticus was found to contain high levels of total phenols, flavonoids and tannins with remarkable potential of antioxidant and antimicrobial activities. The current study provides initial data that justify the use and importance of Astragalus species in Palestinian folkloric medicine. ConclusionOur results showed that A. boeticus was superior to the other 3 species in all the conducted tests. In fact, it had the highest polyphenolic content. In addition, its aqueous extract showed the highest antibacterial activity, while the methanolic extract showed the highest antifungal and antioxidant activities. Further studies are needed to identify and characterize these constituents.