| dc.description.abstract | Ethnopharmacological relevance: Plectranthus amboinicus is used in traditional medicine to treat several
diseases and ailments including opportunistic infections associated with HIV/AIDS. However, there is little
insight as to the possible toxic effects of this herbal formulation on major organ systems of the body. This study
was designed to assess the acute and sub acute toxic effects of the aqueous leaf extract of P. amboinicus on the
histology of tissues, biochemical (liver and kidney functions) as well as hematological indices in albino swiss
mice and wistar rats respectively.
Materials and methods: In this study, phytochemical screening of the aqueous extracts of P. amboinicus was
carried out using standard qualitative and quantitative (SPME and GCMS) analytical methods. The extracts
were tested for acute toxicity in mice and for sub acute toxicity in Wistar rats according to the OECD guidelines
No 425. In acute toxicity test, the dose of 5000 mg/kg was used as the limit dose test. The sub acute toxicity test
was evaluated through biochemical, hematological, histopathological and body weight of rats using daily doses
of 2500 mg/kg, 1250 mg/kg and 625 mg/kg of the aqueous extract for 28 days. Any signs of toxicity were
recorded. Histopathological examination was done on the liver, kidneys, lungs and intestines. Body weight
changes were measured weekly for 28 days of daily single dose of extract administration.
Results: Phytochemical screening of the aqueous extracts revealed the presence of tannins, saponins,
flavonoids, steroid glycosides and polyuronides. GCMS analysis revealed the presence of 11 chemical
compounds constituting 97.6% of the total extract composition. The principle constituents include linalool (50.3
%), nerol acetate (11.6%), geranyl acetate (11.7 %) and carvacrol (14.3%). In acute toxicity, the extracts did not
cause any mortality or evidence of adverse effects following oral administration of the highest dose of 10,000
mg/kg of crude extract in both mice. In sub acute study, normal body weight gains were observed during the
study period compared to the control group. The kidney function parameters (Urea, creatinine, uric acid) were
significantly increased following administration of extract. Histopathological examination of extract treated
groups showed necrosis of hepatic cells with generalized congestion in the renal cortex, pneumonitis and
sloughing of intestinal villi.
Conclusion: The aqueous extract is rich in phytochemical compounds that are of therapeutic value. No
mortalities were observed during acute and sub acute toxicity study period. These finding indicate that the
extract caused treatment- related toxicological abnormalities which increased with dosage. The aqueous extract
of P. amboinicus is safe to use as indicated by the high LD50 value, but should be used with caution at high
doses. | en_US |
