Antibacterial and Antioxidant Activities of Ludwigia Species: Potential Applications in Acne Treatment

Acne vulgaris is a current issue of concern due to its negative impact on the patient's life. Therefore, discovery of new safer treatment with fewer side effects based on natural materials is urgent. Current efforts focus on the exploration of natural medicinal sources to identify bioactive compounds with antimicrobial and antioxidant properties. The genus Ludwigia, belonging to the family Onagraceae has been used in traditional medicine for treatment of hormonal imbalances. However, the investigation on its bioactivities, phytochemistry and pharmaceutical applications remains limited, especially in Vietnam. In this study, five ethanol extracts (L. octovalvis, L. adscendens, L. hyssopifolia, L. prostrata and L. peruviana) were screened for their antibacterial activity against Staphylococcus epidermidis, Staphylococcus aureus, and Propionibacterium acnes. The results showed that the ethanol extract of L. octovalvis (LOE) exhibited the highest antibacterial efficacy against all three tested strains with MIC values of 450 μg/mL, 550 μg/mL and 600 μg/mL, respectively. This extract also showed high antioxidant activity with an IC50 of 18.98 ± 0.09 μg/mL, as determined by the DPPH assay. A preliminary phytochemical study on the bioactive ethanol extract of L. octovalvis revealed the presence of phenolics, flavonoids, saponins, triterpenoids, tannins, glycosides, carotenoids, fixed oil, amino acids and proteins. The quantitative phytochemical analysis displayed a total phenolic content (TPC) of 305.94 ± 1.46 mg GAE/g and total flavonoid content (TFC) 51.42 ± 0.27 mg QE/g. Our report considers the first to investigate the in vitro anti-acne and potential application of L. octovalvis in producing natural skin care products with antimicrobial and antioxidant capabilities.