Acute, Subacute, and Cell Toxicity of the Aqueous Extract of Lippia citriodora

Lemon verbena (Lippia citriodora) has a long history as a folk remedy for the common cold, asthma, colic, fever, diarrhea, indigestion, insomnia, and anxiety. The increasing use of Lippia citriodora and the lack of scientific data on its safety profile make necessary an evaluation of its toxicity.
The present study evaluated the acute, subacute, and cellular toxicity of the aqueous extract of L. citriodora leaves.
The acute and subacute toxicity of the plant was evaluated with a single intraperitoneal (IP) injection of aqueous extract at the dosage range of 0, 1, 2, and 5 g/kg of body weight (acute model) in mice and rats and 21 days’ administration at the dosage range of 0, 50, 100, and 200 mg/kg of body weight. For subacute toxicity, food intake, water intake, body weight, hematological and biochemical parameters, and histopathological changes were evaluated. In our in vitro study, the effect of different concentrations (0, 50, 100, and 200 µg/mL) in HepG2 cells was evaluated using MTT assay.
In the acute toxicity study, the calculated LD50 was 5g/kg of body weight. The subacute toxicity study did not show a significant change in any of the hematological, biochemical, or pathological findings compared to the control group, except for a reduction in triglyceride levels. The cytotoxicity assay also revealed that the viability in all groups was greater than the IC50 value.
Results from the present study elucidated that treatment with the aqueous extract of L. citriodora leaves was well tolerated via daily IP injection at doses up to 200 mg/kg for a period of 21 days and did not produce any toxicity. The safety of L. citriodora aqueous extract was also confirmed by cell viability assay.