Total phenolic content, antimicrobial activity, and LC-MS analysis of Limonium otolepis with isolation of apigenin

Limonium otolepis (Schrenk) Kuntze, a member of the Plumbaginaceae family, was investigated for its phenolic composition and antimicrobial activity. The ethyl acetate extract showed the highest total phenolic content (123.48 ± 10.04 mg GAE/g extract), followed by ethanol and water extracts. Chromatographic separation of the ethanolic extract led to the isolation of apigenin, reported for the first time in this species. LC–MS analysis of the ethyl acetate subfractions predicted several phenolic acids (gallic, caffeic, protocatechuic, syringic acids) and flavonoids (myricetin, hesperetin). Antimicrobial assays at 2 mg/disc concentration revealed that the ethyl acetate fraction displayed the strongest inhibition, particularly against Pseudomonas aeruginosa (14±0.13 mm), whereas the 60% ethanol fraction was less active and the chloroform fraction showed minimal effects. These results highlight L. otolepis as a potential source of bioactive phenolics, with apigenin as one of the key constituents warranting further pharmacological evaluation.