A series of toxicity trials was conducted to analyze the acute and subchronic oral toxicity of calcium from Jeju Lava Seawater (CJLS) in Sprague-Dawley rats. In the acute toxicity trial, rats were administered 0 or a daily dose of 2,000 mg/kg body weight (BW) of CJLS. General behavior, side effects, and mortality were monitored over 14 days. In the subacute and subchronic trials, daily doses of 0, 250, 500, or 1,000 mg/kg BW were administered to the rats over 28 and 90 days, respectively. Clinical signs were examined daily, and changes in body weight, relative organ weight (ROW), and hematological, biochemical, and pathological parameters were recorded. The acute toxicity trial showed that the maximum tolerated dose of CJLS was >2,000 mg/kg BW, with no adverse effects or mortality observed during the 14-day period. In subacute and subchronic trials, oral administration of CJLS at a dosage of 1,000 mg/kg BW/day did not result in significant changes in BW, ROW, or hematological and biochemical biomarkers. These results indicate that the oral administration of CJLS at doses lower than 1,000 mg/kg BW/day is safe for rats, providing a basis for the clinical use of CJLS.

Volcanic seawater has been naturally filtered and purified by volcanic rock layers. It contains abundant minerals such as calcium, magnesium, and iron. This study investigated the genotoxicity of calcium from Jeju lava seawater (CJLS). We performed bacterial reverse mutation assay, chromosomal aberration assay, and mammalian micronucleus test at up to 5,000 g/plate concentrations with or without metabolic activation to determine the CJLS genetic toxicity. None of these tests showed any mutagenic potential. The bacterial reverse mutation assay showed that the CJLS did not induce mutagenicity in Salmonella typhimurium TA98, TA100, TA1535, TA1537, and Escherichia coli WP2uvrA with or without metabolic activation of the S9 mixture. The oral administration of CJLS also did not significantly increase the number of micronucleated polychromatic erythrocytes or the mean ratio of polychromatic to total erythrocytes. Additionally, CJLS did not cause a significant chromosomal aberration in CHL cells in the presence or absence of S9 activation. Therefore, CJLS could be considered as a reliable and safe functional food ingredient.

The study investigated the potential effect of the Ecklonia cava extract by using Jeju lava seawater (ECE-JLS; hardness: 100, 300 mg/L), which is naturally filtered underground by a volcanic rock layer. The chemical composition, antioxidant-related enzyme activities, radical scavenging activities, reactive oxygen species (ROS) production in Vero cells, and nitric oxide (NO) production in Raw 264.7 cells were measured to evaluate the antioxidant and anti-inflammatory activities of the extract. The total polyphenol and flavonoid contents of ECE-JLS100 and 300 were 156.41± 1.15, 166.16±2.27 mg/g, and 343.76±2.40, 373.90±3.67 mg/g, respectively. The concentration of ECE-JLS’ SOD and CAT-like activities was increased. ECE-JLS in the range of 0.25 to 2 mg/mL exhibited remarkable DPPH radical and hydrogen peroxide scavenging activities. ECE-JLS100 and 300 inhibited total ROS generation by 21.4±0.4 and 23.9± 0.3% in H2O2-induced Vero cells at 200 g/mL concentration, respectively. ECE-JLS100 and 300 decreased NO production, with levels of about 55.0±2.4 and 56.5±1.8% at 200 g/mL concentration, respectively. The contents of TNF-  were decreased compared to the negative control. These observations provide helpful information for the potential industrial use of Jeju lava seawater. Also, ECE-JLSW could be used as a functional food material.