Anxiolytic activity of Psidium guajava in mice subjected to chronic restraint stress and effect on neurotransmitters in brain.

The anxiolytic activity of Psidium guajava L. leaf ethanolic extract (PLE) and its effect on neurotransmitter systems was investigated. PLE, extracted using Soxhlet apparatus, was subjected to preliminary qualitative and quantitative (flavonoids and phenols) analyses. The anxiolytic activity at 100, 200, and 400 mg/Kg doses were assessed in mice using elevated plus maze (EPM) and light/dark transition (LDT) test models on days 1 and 16. Neurotransmitters such as monoamines (serotonin, norepinephrine, and dopamine), γ-aminobutyric acid (GABA), and glutamate were estimated in different regions of the brain (cortex, hippocampus, and cerebellum and brain stem). Phytoconstituents identified using gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry were analyzed in silico to evaluate their potential binding mode(s) to GABAA and 5-HT1A receptors. Phytochemical studies showed the presence of alkaloids, tannins, flavonoids, saponins, anthraquinone glycosides, carbohydrates, and proteins, whereas total flavonoid and phenol contents were estimated to be 64.96 ± 0.95 and 206.58 ± 1.60 mg/g of dried extract, respectively. PLE treatment significantly enhanced exploratory activity of mice in EPM and LDT models with significant effects on monoamines, GABA and glutamate levels in the brain. The in silico studies suggested the interaction(s) of PLE component(s) with GABAA /5-HT1A receptors as a potential mechanism of its anxiolytic activity.

Pharmacogenomic assessment of herbal drugs in affective disorders.

Anxiety and depression, the most prevalent psychiatric disorders are co-morbid in nature affecting several people across the world. There is an increase in demand for complementary and alternative medicines, specifically herbal botanicals due to various side effects exhibited by conventional drugs. Herbal drugs mentioned in traditional medicines, face acceptance issues by the medical community due to lack of scientific data regarding their neurochemical pathways. Hence, there has been an increased interest in the quest to unravel the mechanisms of action of herbal psychotropics. With the advancements in "omic technologies" such as genomics, proteomics and metabolomics, research in the field of herbal psychopharmacology has gained momentum, providing a faster and informative platform for thorough evaluation of herbal drugs and formulations. In this article, we have reviewed several medicinal plants and their formulations that have shown potential anxiolytic and anti-depressant activities and have been screened for their biological mechanisms either at the gene, protein or metabolic level.