In Vitro Anti-Acne Activity and Bioactive Compound Analysis of Sargassum cristaefolium Ethanolic Extract from Teluk Awur Jepara

Acne is a prevalent skin disorder, particularly among adolescents, causing significant physical and psychological impacts. Ongoing efforts are dedicated to acne treatment by developing therapeutic agents with enhanced effectiveness while minimizing side effects. In this study, we aimed to assess the potential of Sargassum cristaefolium sourced from Teluk Awur Jepara, extracted using ethanol, in combating acne through its in vitro antibacterial and antioxidant attributes. Utilizing the disk diffusion method, our findings demonstrated the extract's efficacy against Cutibacterium acne, Staphylococcus epidermidis, and Staphylococcus aureus. The minimum inhibitory concentration and minimum bactericidal concentration were determined to be 50 and >100 mg mL-1 against C. acnes, 25 and 100 mg mL-1 against S. epidermidis, and 25 and 100 mg mL-1 against S. aureus, respectively. Additionally, bacteriolytic assays confirmed the extract's ability to partially lyse bacterial cells, particularly S. aureus and S. epidermidis at 2× MIC, while C. acne exhibited partial lysis until the 6th hour, followed by an increase in absorbance, possibly due to cellular debris aggregation or bacterial persistence due to incomplete lysis. Furthermore, the extract exhibited notable free radical scavenging properties against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), with IC50 values of 645.35 ± 9.52 and 574 ± 33.52 µg mL-1, respectively. The S. cristaefolium ethanol extract exhibited a total phenol content of 14.17 ± 0.39 mg GAE g-1 and a sulfate content of 10.99 ± 0.45%. Liquid chromatography-mass spectrometry (LC-MS) analysis identified bioactive compounds, including carotenoids, terpenoids, steroids, flavonoids, chromenols, and fatty acids, all of which demonstrate substantial potential as antioxidants and antibacterial agents against acne-causing bacteria. Therefore, ethanolic extract of S. cristaefolium demonstrates potential as an anti-acne treatment due to its antibacterial and antioxidant properties.