Bioactivity-Guided Evaluation of Extracts and Fractions of Seagrass (Enhalus acoroides): In vitro Antimicrobial and Anti-Inflammatory Activities with LC-MS/MS Characterization.

&lt;b&gt;Background and Objective:&lt;/b&gt; The seagrass &lt;i&gt;Enhalus acoroides&lt;/i&gt; is a marine plant species widely distributed in the waters of Southeast Sulawesi. It is considered a potential source of bioactive compounds with pharmaceutical relevance. This study aimed to characterize the chemical constituents of &lt;i&gt;E. acoroides&lt;/i&gt; rhizomes and evaluate their antimicrobial and anti-inflammatory activities. &lt;b&gt;Materials and Methods:&lt;/b&gt; Phytochemical profiling of the extract and ethyl acetate fraction was performed using Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (LC-MS/MS). Antimicrobial activity was assessed using the microdilution method against &lt;i&gt;Staphylococcus aureus&lt;/i&gt;, &lt;i&gt;Escherichia coli&lt;/i&gt;, and &lt;i&gt;Candida albicans&lt;/i&gt;. Anti-inflammatory activity was evaluated using a protein denaturation assay. The statistical analysis was conducted using SPSS, with a one-way ANOVA at a significance level of p<0.05 (95% CI). &lt;b&gt;Results:&lt;/b&gt; LC-MS/MS analysis identified twelve compounds in the extract and ethyl acetate fraction, including hecogenone, periploca side N, blumenol C glucoside, α-D-glucopyranose-1-hexadecanoate, kushenol R, procyanidin A2, physalin L, Δ5-pregnene-3β,17α,20α-diol, verticiol, quercimeritrin, pterodontoside F, and vitamin K1. Fractions D and E exhibited strong antibacterial activity against &lt;i&gt;S. aureus&lt;/i&gt;, with minimum inhibitory concentrations (MICs) of 2 and 1 μg/mL, respectively, and both showed activity against &lt;i&gt;E. coli&lt;/i&gt; (MIC = 2 μg/mL). Fraction E also demonstrated antifungal activity against &lt;i&gt;C. albicans&lt;/i&gt; (MIC = 4 μg/mL). In the anti-inflammatory assay, fraction E exhibited the highest activity, with an IC&lt;sub&gt;50&lt;/sub&gt; of 29.48 μg/mL. &lt;b&gt;Conclusion:&lt;/b&gt; The findings indicate that &lt;i&gt;E. acoroides&lt;/i&gt; rhizomes are a promising source of bioactive compounds with significant antimicrobial and anti-inflammatory potential.