A Comparative Assessment on the Cytotoxicity of Kappaphycus alvarezii and Kappaphycus striatus Seaweeds using Brine Shrimp Lethality Assay

Abstract

Seaweed farming plays a crucial role in the Philippine economy, particularly in the Caraga region, where the cultivation of Kappaphycus spp. is highly prevalent and abundant. This study provided a preliminary assessment on its toxicology with a comprehensive comparison between K. alvarezii and K. striatus collected from Barobo, Surigao del Sur. Brine shrimp lethality assay (BSLA) was employed to assess the cytotoxic activity of both species. Results revealed that both methanolic crude extracts of two species exhibited bioactivity (% mortality) towards the test samples with highly significant Spearman’s rho correlation among all concentrations (p<0.001). Comparison of extracts per concentration also revealed that K. alvarezii significantly exhibited higher mortality over K. striatus at concentrations of 1000 μg/mL (p<0.001) and 10 μg/mL (p<0.01). Median Lethal Concentration (LC₅₀) values showed that K. alvarezii (38.9 ppm) had higher lethality compared to K. striatus (2187.76 ppm) with a highly significant statistical difference value of 45.54 (p<0.0001). This study showed potential pharmaceutical implications for both species of Kappaphycus. Moreover, the significantly higher lethality of K. alvarezii indicates it as a more promising species for further studies on bioactivity potential and medicinal research. Studies on these fields would mean an additional potential market for the thriving seaweed industry in Caraga, Philippines.