The use of antimicrobial compounds obtained from natural sources has been gaining impact in recent years. However, when planning to use these compounds in living beings, careful and exhaustive examination of potential toxicity is necessary. In the present work, we characterized the chemical composition of an aqueous extract of Larrea tridentata and evaluated the toxicity when administered orally to Wistar rats in both single and repeated dosing regimens. Spectrometric characterization of the aqueous extract was performed. Female Wistar rats were inoculated orally with single and repeated doses of the vegetable leaf extract and biochemical parameters and cytokine gene expression were evaluated. Mass spectra of the aqueous extract showed the presence of nordihydroguaiaretic acid (NDGA) and kaempferol along with other non-identified compounds. Rats treated with one dose of the aqueous extract did not show clinical manifestations of acute toxicity. However, treatment over four consecutive weeks, showed significant differences between the study groups in observed food and water consumption and hepatic enzyme levels (P < 0.05). Downregulation of genes coding for TNF-a, IL-1β and IL-6 with respect to the control animals was observed in liver and kidney of the animals receiving the aqueous extract.

Keywords: Larrea tridentate; NDGA; Mass Spectrometry; Acute Toxicity; Chronic Toxicity;