Extraction of centella asiatica leaves: potential antioxidant and antibacterial activity on skin / Norshamira Suhaimi

In Malaysia, marine green algae distributed abundantly in the intertidal zone in tropical and subtropical regions. The study used green algae from family Caulerpa which is C. lentillifera from Kuala Kedah. Numerous beneficial biological benefits of marine natural compounds, such as antioxidants and antibacterials, have been demonstrated. Recent studies have revealed the biological potential of several of the bioactive components of C. lentillifera, including phenolic compounds, polysaccharides, and pigments, which may serve as a rich source of novel medications for the pharmaceutical sector. However, the potential for the green alga C. lentillifera from Kuala Kedah to be a source of bioactive compounds has not been sufficiently investigated. The study was carried out to assess the phytochemical composition present in the crude extract of C. lentillifera for the detection of antioxidants and antibacterial activities. In this study, it has been shown that C. lentillifera purchased from Kuala Kedah is a rich source of bioactive substances with potential nutritional value such as flavonoids, polyphenol, terpenoids, alkaloids, saponins, and tannins. The TPC of the extracts was determined according to the Folin-Ciocalteu method, yielding a result of 13.02 ± 0.00 μg GAE/mg of ethanolic extract and 9.62 ± 0.01 μg GAE/mg of chloroform extract. Antioxidant activity was determined using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay with different concentrations that ranged between 20 to 100 μg/mL, noted C. lentillifera as the highest in DPPH reduction (58.56%) at 100 ug/mL concentration for ethanolic extract, with an IC50 of 3.22 μg/mL. The potential of C. lentillifera's ethanolic extract as a natural antioxidant is demonstrated, in contrast to the extract of C. lentillifera in chloroform. When compared to ethanolic extracts, chloroform exhibits a stronger antibacterial action against B. licheniformis (15.33±0.58 mm), followed by gram-negative bacteria, E. coli (14.00±2.00 mm).