Evaluation of the toxicity of aqueous and 80% methanol extracts of selected medicinal plants used for liver diseases in Gamo Community, South Ethiopia, using the brine shrimp lethality assay

Abstract

Despite the widespread belief that “natural” traditional remedies are inherently safe, limited scientific evaluation raises important safety concerns. Liver diseases account for over two million deaths annually worldwide, and numerous Ethiopian medicinal plants—including Clutia lanceolata (C. lanceolata) , Amaranthus caudatus (A. caudatus) , and Solanum incanum (S. incanum )—are traditionally used for their management despite the lack of sufficient toxicological evidence. Therefore, this study aimed to assess the potential toxicity of aqueous and 80% methanol leaf extracts of C. lanceolata and A. caudatus , and root extract of S. incanum , using the Artemia salina lethality assay. The plant materials were extracted using maceration and decoction methods. Brine shrimp lethality assay (BSLA) was used to preliminarily explore the toxicity of the plant extracts. Brine shrimp eggs were hatched into nauplii, and the harvested nauplii were co-incubated with different concentrations of plant extracts to determine the mortality rate and lethal concentration 50% (LC 50 ). LC 50 were determined from the 24 h counts using probit analysis. 80% methanol extracts yielded a higher percentage across all plants (5.4–8.1%). The toxicity of the extracts varied by plant species and solvent type. All of the three tested aqueous extracts exhibited to be highly toxic (LC 50 <100 µg/mL). The highest toxicity was noted with A. caudatus (LC 50 = 1.91 µg/mL). All the tested 80% methanolic plant extracts also showed high toxicity to Artemia salina nauplii, with the highest toxicity observed for C. lanceolata (LC 50 = 1.28 µg/mL). There was concentration and time dependent percent mortality, reaching 100% for all extracts within 24 h at the maximum concentration (1000 µg/mL). The control group (treated with distilled water) showed minimal mortality. The study revealed that aqueous and 80% methanol extracts of the tested plants are highly toxic, necessitating their cautious use.