Comparative study of Posidonia oceanica L.: LC/ESI/MS analysis, cytotoxic activity and chemosystematic significance

Posidonia oceanica L., one of nine Posidonia species belongs to family Posidoniaceae, is completely restricted to the White Mediterranean Sea. The chemical components of the aqueous methanol extracts of P. oceanica leaves and balls were analyzed using LCESI- MS technique for the detection and identification of its genuine constituents. Six phenolic acids, six flavonoids, two chalcones, two hydroxyl benzenes, three fatty acid derivatives, one anthocyanin and one sterol were identified or tentatively characterized. Also, the cytotoxic activity of the two extracts were investigated against epidermal carcinoma cell lines of larynx (Hep2), colon (HCT116), liver (HepG2) and breast (MCF7). The leaves extract exhibited obviously higher antiproliferative activity against HepG2 cell line with IC₅₀ 17 µg/ml and a moderate activity against Hep2 and HCT116 with IC₅₀ 28.3 and 27.8 (µg/ml), respectively while the balls extract showed moderate activity against HepG2, MCF7 and HCT116 with IC₅₀ 24.3, 22.6 and 22.5 (µg/ml), respectively. The antiviral activity of the two extracts was also investigated against H5N1 virus, the balls extract showed a moderate % inhibition (45%) and no activity observed for the leaves extract. Furthermore, the chemosystematic significance was characterized to compare between P. oceanica and other seagrass species.