Antidepressant-like effects of a methanol extract of Leonotis nepetifolia in mice.

This study evaluated the antidepressant-like effects of a methanol extract of Leonotis nepetifolia in behavioural tests in mice. Our results showed that a single administration of the extract significantly reduced immobility behaviour in the tail suspension test, while three administrations were necessary to diminish immobility behaviour in the forced swimming test. A daily dose of the extract for 28 days improved body weight gain and significantly reduced corticosterone levels of mice exposed to chronic unpredictable mild stress. Metabolic profiling of the extract revealed that nepetaefolin, methoxynepataefolin, and 7-O-ß-glucoside luteolin were the main products. Acute and repeated administration of the extract produced antidepressant-like effects in animals subjected to chronic stress. Our results suggest the hypothalamus-hypophysis-adrenal axis participates in the antidepressant actions of the extract. These results show that alterations in behaviour elicited by stress can be prevented with L. nepetifolia treatment.

Calea zacatechichi Schltdl. (Compositae) produces anxiolytic- and antidepressant-like effects, and increases the hippocampal activity during REM sleep in rodents.

ETHNOPHARMACOLOGICAL RELEVANCE: Calea zacatechichi is a plant with an extensive popular and ritual use in Mexico. In healthy volunteers, it induces well-being and tranquility senses, and facilitates superficial stages of sleep. However, anxiolytic, and antidepressant-like effects and changes on the sleep-waking stages have not been explored. AIM: To determine anxiolytic and antidepressant-like effects of an aqueous extract of C. zacatechichi (CZ) in rodents and to analyze their effects on hippocampal activity in the rat sleep-waking cycle. MATERIAL AND METHODS: CZ anxiolytic- and antidepressant-like effects were evaluated in several mice and rat behavioral paradigms. CZ effects on temporal distribution of sleep were described, and hippocampus EEG frequency patterns were analyzed during the sleep-waking cycle; absolute and relative powers were analyzed during Rapid Eye Movements (REM) and non-REM sleep stages. CZ chemical analysis was performed by UPLC-ESI-MS. RESULTS: CZ produced specific and robust anxiolytic- and antidepressant-like effects in mice and rats, similar to those of prototypical drugs, at doses ranging from 0.5 to 50 mg/kg. CZ at 100 mg/kg produced visible mild sedative effects in rats, associated with a significant increase in Slow Wave Sleep episodes during a 6 h recording, and enhanced fast frequencies of hippocampus (gamma-band:31-50 Hz) during REM sleep. CONCLUSION: Results could support the well-being and tranquility senses reported by healthy consumers, and to explain the oneiric content during dreams and some improvements in cognitive processes described by consumers. Anxiolytic- and antidepressant-like effects of this species, reported for first time in this study could improve some aspects of mental health.