Phytochemical screening, antioxidant potential, and cytotoxic effects of different extracts of red algae (Laurencia snyderiae) on HT29 cells

BACKGROUND AND PURPOSE: Marine algae are potential renewable and sustainable sources of bioactive natural products which can be utilized in nutraceutical and pharmaceutical industries. EXPERIMENTAL APPROACH: Different extracts (methanol, chloroform, and ethyl acetate) of red algae, Laurencia snyderiae, was evaluated for their antioxidant potential, with various antioxidant assessment assays, cytotoxic properties (using MTT colorimetric assay), and phytochemical constituents (total phenolic and flavonoid contents). The GC-MS analyses of the algal methanolic extract and its apoptotic effects on the human colon carcinoma cell line (HT29) were also investigated. FINDINGS/RESULTS: The total phenolic content in the methanol, chloroform, and ethyl acetate extracts of L. snyderiae was 3.6 ± 0.12, 3.2 ± 0.41, and 3.3 ± 0.35 μg/mg of gallic acid, respectively. Among different algae extracts, chloroform extract showed significantly chelating ability (IC(50) = 0.027 mg/mL) and reducing power activity (IC(50) = 0.082 mg/mL), while the highest DPPH scavenging activity (IC(50) = 0.058 mg/mL) exhibited in the methanol extract compared to the other extracts. The methanolic extract was found to have a higher cytotoxicity effect on colon carcinoma cells with IC(50) 70.2 μg/mL. The viability of the cancer cells was increased with the decrease in the concentration in different extracts. GC-MS analysis of the algal methanolic extract revealed the presence of active antitumor constituents and apoptosis-based cytotoxicity against colon cancer cells through the DNA damage was also confirmed. CONCLUSION AND IMPLICATIONS: Based on these results, the red algae L. snyderiae possesses potent bioactive constituents and can use as additional resources as a natural antioxidant and antitumor agent in the pharmaceutical and nutraceutical area.