Refined Up-and-Down Methodology: Acute Toxicity Evaluation of Lemna minor Linn Extract in Wistar Rats for LD50 Determination

The primary objective of this study was to evaluate the acute toxic effects of Lemna minor Linn extract to ensure the safety and efficacy of this herbal remedy, following the OECD Test Guideline No. 425. Female Wistar rats were divided into two groups, with one serving as the control and the other receiving an oral dose of 100, 300, 750, 1000, 2000mg/kg b.w. of Lemna Minor Linn extract. The LD50 was found to be greater than 2000mg/kg b.w., indicating a relatively low acute toxicity. However, behavioral observations over a 14-day period revealed mild changes, such as a moderate increase in respiration rate during the first thirty minutes and a transient rise in somatomotor activity for the initial four hours of the trial. Despite the LD50 exceeding 2000mg/kg, macroscopic examination of vital organs disclosed mild to focal pathological changes in the liver, kidney, lung, and heart. These findings suggest that while the acute toxicity is low, there are discernible impacts on certain organs. In conclusion, further investigation is warranted to ascertain the safety of Lemna Minor Linn for prolonged use and to explore potential multiple-dose effects. This study emphasizes the importance of comprehensive toxicity assessments to ensure the overall safety profile of herbal remedies, even when acute toxicity levels are seemingly low.