Effects of Polycyclic Aromatic Hydrocarbons Pollution on the Macro-Compositions and Bioactivity of Extracts from Lithophaga lithophaga (Linnaeus, 1758), Egypt

        Marine bivalves, a rich source of many chemical compounds with potential nutraceutical and pharmaceutical applications, can be affected by pollutants. Therefore, this study investigated the impact of polycyclic aromatic hydrocarbon (PAH) pollution on the biochemical composition and bioactivity of extracts from the edible date mussel Lithophaga lithophaga, collected from the Eastern Harbor and Abu-Qir Bay in Alexandria, Egypt. Mussels from the Eastern Harbor, having lower PAH levels, exhibited higher protein, ash content, and antioxidant capacity than those from Abu-Qir Bay. The ethanolic extract showed the highest yield of compounds via gas chromatography-mass spectrometry (GC-MS) analysis, along with the highest total phenolic content (TPC) and total antioxidant capacity (TAC), making it the focus of further biological assessments. The ethanolic extract prepared from the Eastern Harbor samples (EHEE) exhibited superior antioxidant activity with a low value of median inhibitory concentration (IC₅₀: 576.80µg/ mL) compared to the ethanolic extract prepared from Abu-Qir Bay samples (AQEE) (IC₅₀: 796.13µg/ mL). In the anticancer assay, EHEE was more effective against HepG2, MDA-MB-231, and HeLa cancer cell lines with IC₅₀ values of 370.15, 260.89, and 243.62µg/ mL, respectively. Although both ethanolic extracts, EHEE and AQEE, demonstrated antibacterial activity against Gram-positive and Gram-negative bacteria, EHEE showed a notable 20.66mm inhibition zone against Candida albicans, which was significantly larger than that recorded for AQEE. In conclusion, these findings suggest the significant influence of solvent choice and PAH pollution on the bioactivity of compounds in L. lithophaga, as the ethanol extract of samples collected from the Eastern Harbor (EHEE) holds more potential for pharmaceutical development than AQEE.