Pharmacological studies of Malaysian Beilschemidia species (Lauraceae)

Abstract

The genus Beilschmiedia is a pantropical genus of about 287 species most commonly represented in southeast Asia and Africa. The ethnopharmacological history of Beilschmiedia indicates that some species have been used in local medicine to treat various conditions, including uterine tumors, rheumatism, pulmonary disorders, bacterial infections, malaria and tuberculosis. Because of their versatile therapeutic traditional uses, extensive phytochemical investigations have been carried out on Beilschmiedia plants which led to isolation of several classes of natural products including, terpenoids, endiandric acid derivatives, lignans/neolignans, amide/alkaloids and flavonoids. Both in vivo and in vitro experiments have indicated that the Beilschmiedia plant extracts possessed a wide range of pharmacological properties, including antioxidant, anti-inflammatory, cytotoxicity, antibacterial and antifungal activities. Consideration of the important of medicinal uses of this genus in the treatment of many types of ailments, it is clear that a broader range of biological activity studies are required to explore their pharmacological properties. These gaps open an important research opportunity to further study the phytochemistry and pharmacology of genus Beilschmiedia. The aim of this study was to investigate in vitro biological activities of various extracts, obtained from five Beilschmiedia species from Malaysia, which are B. kunstleri, B. madang, B. maingayi, B. penangiana, and B. pulverulenta. The bioactivity studies were determined on their antioxidant, antityrosinase, anti-inflammatory, and anti-a-glucosidase activities. Evaluation of antioxidant activities were tested against DPPH, ABTS, ß-carotene/linoleic acid bleaching, and phenolic content assays. Antityrosinase and anti-inflammatory inhibition activity were analysed using mushroom tyrosinase and 5-lipoxygenase enzyme, respectively, while anti-a-glucosidase activity against a-glucosidase enzyme from Saccharomyces cerevisiae. The MeOH extract of B. pulverulenta showed the highest activity on DPPH and ABTS assay which gave IC50 values of 65.7 and 114.2 µg/mL, respectively. The MeOH extracts of B. kunstleri revealed the highest percentage inhibition on tyrosinase and anti-inflammatory activity, which showed 85.1% and 66.6%, respectivley, while for anti-a-glucosidase activity, the EtOAc extract of B. kunstleri demonstrated the highest activity (80%). The results demonstrated that five Beilschmiedia species possessed significant activities on various biological studies. The isolation of specific bioactive compounds through bioassay-guided fractionation and their characterization as well as studies evaluating their safety may be necessary in the exploration of these species for potential new therapeutic drugs or drug leads.