Phytochemical analysis, antioxidant activity, and cytotoxic effects of Caulerpa lentillifera extracts inducing cell apoptosis and sub-G/G0-G1 cell cycle arrest in KON oral cancer cells.

Background: Marine algae have excellent phytoconstituents with notable biological activity and bioactive therapeutic benefits, but the anti-oral cancer activity of Caulerpa lentillifera (C. lentillifera) has not been widely studied. This study aimed to explore the anti-cancer properties of C. lentillifera to gain insights into possible treatment approaches.

Methods: The three C. lentillifera extracts were prepared using the maceration method with methanol (CLM), ethanol (CLE), and acetone (CLA). The chemical composition of extracts of C. lentillifera was investigated. Its metabolite profiles were selectively further investigated using the LC-QTOF MS/MS technique and their antioxidative activity was evaluated. The cytotoxic effect on KON cells and MRC-5 cells was assessed using the MTT test. Morphological changes and apoptosis were examined through Hoechst 33,258 and AO double staining, while DAPI and FDA double labeling were used to observe the nucleus and cytoplasm. Using a flow cytometer, the percentage of cell cycle arrest was calculated and the fraction of cell death was examined.

Results: The CLA exhibited higher quantities of TPC, TFC, chlorophyll a, and chlorophyll b compared to the CLM and CLE. The LC-QTOF MS/MS analysis revealed ten major phytochemicals in the CLA. The three C. lentillifera extracts exhibited antioxidative activity, with the CLE demonstrating significantly higher antioxidant activity compared to the CLM and CLA. In-vitro, the KON oral cancer cells exhibited sensitivity to CLA, CLE, and CLM in that order. The three extracts induced ROS-mediated cell death as well as disruption of mitochondrial membrane potential, with concentrations at IC₄₀, IC₆₀, and IC₈₀ leading to apoptosis within 24 h. Furthermore, the cell cycle of KON cells was blocked in sub-G and G0-G1 by all three extracts. Notably, the extracts significantly impeded colony growth, migration, and invasion. The increase in cellular uptake was measured using the TEER test.

Conclusion: The findings showed that C. lentillifera has several functional metabolites, antioxidative activity, and strong anti-tumor properties. According to these results, C. lentillifera extracts may be utilized to treat oral cancer.