Exploration of Antidepressant Efficacy of Kantakari Flower (Solanum Xanthocarpum) Extract and Its Comparative Analysis With Fluoxetine Hydrochloride on Behavioural and Neurochemical Alterations

Abstract

Major depressive disorder affects an estimated 280–330 million people worldwide and remains a leading contributor to years lived with disability. Beyond the classical monoaminergic deficit, converging evidence implicates hypothalamic–pituitary–adrenal (HPA) axis hyperactivity, neuroinflammation and oxidative stress in the pathogenesis of stress-related depression. Currently available antidepressants act slowly, fail in a substantial minority of patients and carry a considerable adverse-effect burden, which sustains interest in multi-target, plant-derived candidates. Solanum xanthocarpum Schrad. & Wendl. (Kantakari), a Solanaceous medicinal plant used extensively in Ayurveda with documented antioxidant and anti-inflammatory activity; its flowers, however, remain pharmacologically unexplored. To evaluate the antidepressant potential of a hydroalcoholic Kantakari flower extract in a cold water immersion (CWI) model of stress-induced depression in rats and to benchmark it against fluoxetine. Twenty-five Wistar rats (150–250 g) were randomised into five groups (n = 5): normal control; CWI (disease) control; CWI + fluoxetine (10 mg/kg); CWI + Kantakari flower extract (200 mg/kg); and CWI + Kantakari flower extract (400 mg/kg). Animals were immersed in cold water for 10–15 min daily for 21 days, with oral treatment given concurrently. Locomotor activity (actophotometer) was recorded on days 8, 10, 12, 14, 18 and 21, and immobility time (forced swim test) on days 10, 14, 18 and 21. Brain superoxide dismutase (SOD) and reduced glutathione (GSH) were quantified, and cortical and hippocampal sections were examined after haematoxylin–eosin staining. Data were analysed by one-way ANOVA with Tukey's post hoc test. CWI produced a progressive fall in locomotor activity (93.6 ± 5.3 vs. 290.4 ± 2.3 in normal controls on day 21; p < 0.05) and a rise in immobility time (207.0 ± 6.7 s vs. 63.4 ± 7.2 s; p < 0.05), together with depletion of brain SOD and GSH and marked neuronal degeneration. Both Kantakari flower extract doses significantly reversed these changes relative to disease controls (p < 0.05). Kantakari flower extract 400 mg/kg restored locomotor activity to 333.0 ± 8.5 and Reduced immobility to 75.2 ± 6.3 s by day 21, normalized antioxidant indices and largely preserved neuronal architecture, matching fluoxetine. Kantakari flower extract exerts dose-dependent antidepressant-like activity in CWI-stressed rats, plausibly through reinforcement of endogenous antioxidant defenses and consequent neuroprotection.