EVALUATION OF TOXICITY POTENTIAL OF Micromeria imbricata IN WISTAR RATS

Abstract

Micromeria imbricata (Lamiaceae) is widely employed in ethnomedicine for its antimicrobial, anti-inflammatory, and antioxidant properties. However, there is limited scientific information on its safety profile. This study evaluated the acute and sub-chronic toxicity potential of methanolic leaf extract of M. imbricata in albino rats. The extract was prepared by cold maceration in methanol and administered orally to Wistar albino rats. Acute toxicity was determined using Lorke’s method, while sub-chronic toxicity was assessed at doses corresponding to 1/20, 1/40, and 1/80 mg/kg of the LD50 over 14 days. Serum biochemical markers, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total protein, albumin, and bilirubin, were determined. The oral LD50 of the extract was estimated at 2154 mg/kg, indicating moderate toxicity. Sub-chronic administration significantly (p < 0.05) elevated liver enzyme levels compared to control. ALT increased from 90.5 ± 7.50 U/L (control) to 160.33 ± 25.00 U/L at 26.90 mg/kg, AST rose sharply from 150.00 ± 80.25 U/L to 893.33 ± 465.40 U/L at 107.00 mg/kg, while ALP increased from 349 ± 13.85 U/L to 471.33 ± 38.67 U/L at 26.90 mg/kg. Similarly, total bilirubin increased from 11.7 ± 2.02 mg/dL to 54.4 ± 1.38 mg/dL, and direct bilirubin from 7.25 ± 2.62 mg/dL to 23.05 ± 5.05 mg/dL. These alterations indicate hepatocellular leakage and impaired liver function. The study demonstrates that while M. imbricata possesses ethnomedicinal value, its methanolic extract exerts dose-dependent hepatotoxic effects in albino rats. Caution is advised in its traditional use, and further studies including histopathological evaluations and isolation of active compounds are recommended to establish safe therapeutic limits.