Gastroprotective and toxicological evaluation of the Lithothamnion calcareum algae

Abstract

Lithothamnion calcareum is a red alga of the Corallinacea family whose main feature is the formation of calcium carbonate precipitate in its cell walls. L. calcareum is marketed as a nutritional supplement for calcium and other minerals in Brazil and other countries under the pharmaceutical name of Vitality 50+. In this study, gastroprotective and pre-clinical toxicity assays were performed on this product. Doses of 30, 120 and 480 mg/kg were used in the gastroprotective study on Wistar rats. A dose of 2000 mg/kg was used in the preclinical acute toxicity study and oral doses of 1000 and 2000 mg/kg were used in the subchronic toxicity evaluation. L. calcareum played no significant role in the protection of the rats' gastric mucosa, nor did it cause increase in gastric irritation. No impact on the acute toxicity test was identified. In the subchronic toxicity test, serum levels of albumin, total protein and calcium decreased, and creatinine levels increased, suggesting hypercalcemia and possible kidney damage associated with liver damage, given that the majority of these parameters were irreversible. Thus, this work aims to discuss the relationship of the high concentration of calcium in the product with the observed effects.

Evaluation of acute and sub-chronic toxicity of lithothamnion sp. in mice and rats

“…Mice are often used in acute toxicity studies9 [ 14 ] and were also deemed appropriate for the purposes of this study. Significantly, this is a higher dose level than the LD 50 level already published (2 g/kg BW in rats) [ 11 ]. Although acute toxicity studies often test doses in the range of 5 g/kg BW [ [12] , [13] , [14] ], a higher dose was chosen for this study based on preliminary studies that indicated very low toxicity for this particular product.…”

“…However, published comprehensive toxicological data on Lithothamnion sp. calcium are sparse, excepting one other publication [ 11 ], and given the wide-ranging applications of this bioavailable source of calcium and other minerals, completing and publishing these studies was deemed important.…”

“…Interestingly, these results are not in accordance with the results reported in another Lithothamnion sp. toxicity study in which increases in serum creatinine were observed at the higher treatment dose [ 11 ]. The reason for this discrepancy is not clear at this time, although the test substances in these studies may differ in their composition, as this particular study was performed on a Brazilian product.…”

“…However, published data on the toxicological effects of Lithothamnion sp. calcium are sparse, with the exception of only one study [ 11 ] investigating a Brazilian product, which may not be directly relatable to Lithothamnion sp. harvested in North Atlantic waters based on variations in mineral composition and processing techniques.…”

Feasibility single-arm study of a medical device containing <em>Desmodium adscendens</em> and <em>Lithothamnium calcareum</em> combined with chemotherapy in head and neck cancer patients

“… 20 On the other hand, oligo-elements function to balance the nervous system as demonstrated by several studies conducted to establish the efficacy of single trace elements. 21 , 22 …”