Egyptian red sea seagrass as a source of biologically active secondary metabolites

Abstract

Background and objective The Red Sea seagrass Halophila stipulacea (Forsskal) Ascherson and Thalassodendron ciliatum (Forsskal) den Hartog were poorly investigated either for their biological activities or for chemical constituents. This study aims to investigate the phytochemical constituent of both grass, along with studying the different biological activities (osteoclastogenesis, antioxidant activity, and anticancer activity) of the crude extract as well as purified compounds. Materials and methods The present study used three different in-vitro bioassay methods to screen the fractions and/or isolated compounds of both seagrass, to assess their possible biological activity. Osteoclastogenesis assay, antioxidant activity, and anticancer activity were carried out using different assays of the different anticancer mechanism of action. Results and conclusion Ten secondary metabolites were isolated and identified for the first time from Red Sea seagrass H. stipulacea (Forsskal) Ascherson: (1) p-hydroxybenzoic acid, (2) bis(2-ethyl hexyl) phthalate, (3) benzoic acid, (4) p-hydroxybenzaldehyde, (5) thymidine, (6) stigmasterol, (7) oleic acid, (8) linoleic acid, (9) linoleic methyl ester, and (10) apigenin. Furthermore, a new dihydrochalcone and a known flavonoid were isolated and identified from Red Sea seagrass T. ciliatum (Forsskal) den Hartog: (11) 2,4′ dihydroxy-4-methoxy-6-glucosyl dihydrochalcone (Thalassodendron B) and (12) rutin. Fractions of both seagrass showed promising biological activities.