Assessing Acute and Subacute Toxicity and Phytochemical Screening of the Methanolic Extract of Foeniculum vulgare in Wistar Rats.

Foeniculum vulgare, commonly known as fennel, has a long history of use in traditional medicine, particularly for treating problems related to the digestive, endocrine, reproductive, and respiratory systems. The major constituents found in fennel seed extracts are trans-anethole (68.6%-75.0%), fenchone (8.40%-14.7%), and methyl chavicol (5.09%-9.10%). However, before introducing this plant into the human environment, it is essential to understand its toxicological properties. In this study, we investigated the acute and sub-acute toxicity of methanolic extracts of F. vulgare. A phytochemical screening was performed to identify the major chemical constituents of the plant. For the acute toxicity study, female Wistar rats received a single dose of the methanolic extract of F. vulgare at doses of 1000, 2000, 3000, and 5000 mg/kg for 14 days. In the sub-acute toxicity study, the methanolic extract of F. vulgare was administered orally daily at doses of 125, 250, and 500 mg/kg for 28 days. Hematological, biochemical, and histological changes were evaluated. Phytochemical tests were also performed. The phytochemical analysis showed that the methanolic extract of F. vulgare is rich in flavonoids, catechic, gallic tannins, and total polyphenols. Toxicological tests showed no animal deaths, suggesting that the LD₅₀ was greater than 5000 mg/kg. In the sub-acute oral toxicity study, no significant differences were observed in body weight, food consumption, or water intake. Additionally, there were no significant changes in hematological and biochemical parameters or differences in the macroscopic and microscopic examination of organs. Therefore, this study concludes that the methanolic extract of F. vulgare, at the doses tested, is considered non-toxic under the conditions evaluated.