Identification and Characterization of Bioactive Compounds from a Marine Bivalve Clam Marcia hiantina via Mass Spectrometry Techniques

Background: Bioactive compounds with unique functional properties from marine bivalves have been gaining attention. Several investigations have demonstrated that marine proteins and peptides have exhibited biological activities. Marcia hiantina is a bivalve clam found in many coastal regions in the Philippines but is underutilized despite its nutritional value. Objective: The study aimed to isolate bioactive compounds from M. hiantina using a mass spectrometry- guided technique to separate target analytes and characterize their biological activities. Methods: Bioactive fractions were detected by combining liquid chromatography-mass spectrometry (LC-MS) and high-performance liquid chromatography (HPLC) with biological assays, and the bioactive compounds were thereafter identified by ultra-high-performance liquid chromatography-high resolution-elevated energy mass spectrometry (UHPLC—MSE) technique. Results: A UHPLC-MSE analysis of the isolate revealed polymeric tryptophan (Trp) and its metabolites. The M. hiantina-derived peptide exhibited inhibitory effects on the proliferation of human breast cancer cells (MCF-7) with an IC50 value of 95.20 ± 0.11 µg/mL, measured by 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Moreover, the peptide also inhibited the growth of Gram-positive and Gram-negative bacterial strains tested and showed strong antioxidant potential as a 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenger (73.54 % at 2.5 mg/mL). Conclusion: Our findings demonstrated the complementary nature of mass spectrometry techniques in conjunction with bioassays for identifying bioactive constituents in the marine clam M. hiantina. The proposed approach will become our pilot study on the LC-MS guided profiling and identification of bioactive compounds from marine bivalves using UHPLC- MSE techniques. This study revealed that M. hiantina is a new source of bioactive compounds and can be a promising novel ingredient in functional foods promoting health and well-being.