Green algae Caulerpa microphysa is relatively valuable economically, mostly consumed as food. Polysaccharides contained in C. microphysa have anti-tumor, antibacterial, and skin-protective activities. However, there is no scientific study about biological properties and identification of phytoconstituents present in the oil extract from C. microphysa. This study aims to assess the potential use of the oil extract from C. microphysa collected from Hon Son, Kien Giang, Vietnam in terms of antioxidant, anti-inflammatory, anti-bacterial, and anti-ultraviolet activity. The antioxidant effects of the oil extract from C. microphysa were significantly high in DPPH and ABTS radical scavenging activity with EC₅₀ values of 8.27% and 0.38% concentration, respectively. The inhibition denaturation of bovine serum albumin for the oil extract showed an EC₅₀ value of 12.9% amount. The antibacterial activity of the oil extract from C. microphysa is illustrated by the potential inhibitory against Bacillus subtilis, Staphylococcus aureus, Listerria innocua, and Escherichia coli. Also, this study identified 26 components in the oil extract, with abundant acetic acid, 2-(2,2,6-trimethyl-7-oxa-bicyclo[4.1.0]hept-1-yl)-propenyl ester accounting for 43.87%. This study revealed the significant role of phytochemical substances in the oil extract from C. microphysa, which may apply to potential cosmetic production.
Key Words: antioxidant, anti-bacterial, anti-inflammatory, anti-ultraviolet activity, Caulerpa microphysa.