Sangeeta Pilkhwal Sah

Effect of quercetin on lipopolysaccharide induced-sickness behavior and oxidative stress in rats

Objectives: Gram-negative infections and control infusion of recombinant cytokines in human have been shown to induce sickness behavior characterized by fever, prolong sleep, decreased food and water intake, reduced mobility, depression, and anxiety. Therefore, the present study was undertaken to investigate the effect of bioflavonoid quercetin in lipopolysaccharide (LPS)-induced sickness behavior. Materials and Methods: Wistar albino rats were divided into six groups (n=6). Three groups received vehicle and two doses of quercetin (2 and 25 mg/kg, i.p.) respectively for 2 weeks before being challenged with LPS (1 mg/kg, i.p). One group received vehicle for 2 weeks and was challenged with saline on day 15. The per se effect of quercetin (2 and 25 mg/kg, i.p.) was also seen after 2 weeks of dosing. LPS-induced sickness behavior in rats was quantified by measuring time in social exploration, anxiety, food and water consumption, and weight loss. Levels of cytokines (TNF-α, IL-1β, and IL-6) and oxidative stress in rat brain were also analyzed. Results: Quercetin (2 and 25 mg/kg) administration significantly (P<0.05) attenuated LPS-induced sickness behavior by modulating cytokines production as well inhibiting LPS-induced oxidative stress. Conclusions: Adequate intake of dietary flavonoids (like quercetin) may help promote recovery from sickness behavior.

Involvement of nitric oxide (NO) signalling pathway in the antidepressant activity of essential oil of Valeriana wallichii Patchouli alcohol chemotype

Valeriana wallichii DC (Valerianaceae), popularly named as Indian valerian has been shown to exist as three chemotypes. The present study evaluated the antidepressant like effect of root essential oil of Valeriana wallichii patchouli alcohol chemotype in both acute and chronic treatment study using forced swim test (FST). Mice (n=6 per group) received 10, 20 and 40 mg/kg p.o. doses of test drug. Single administration of oil significantly inhibited the immobility period (57.6% and 46.9%) at doses 20 and 40 mg/kg respectively without changing the motor function (p<0.05). Similarly, daily administration of essential oil (20mg/kg) for 14 days significantly reduced the immobility period (69.9%) in FST (p<0.05). The neurotransmitter levels in mouse brain were estimated on day 14 after the behavioral study. Significant increase in the level of norepinephrine (29%) and serotonin (19%) (p<0.05) was found at 20mg/kg dose, while no change was observed at 10 and 40 mg/kg doses. The antidepressant-like effect of essential oil (20mg/kg) was prevented by pretreatment of mice with l-arginine (750 mg/kg i.p.) and sildenafil (5mg/kg i.p). On the contrary, pretreatment of mice with l-NAME (10mg/kg i.p.) or methylene blue (10mg/kg i.p.) potentiated the antidepressant action of essential oil (10mg/kg). Taken together, these findings demonstrated that nitric oxide pathway is involved in mediating antidepressant like effect of essential oil from this chemotype.

Antidepressant effect of Valeriana wallichii patchouli alcohol chemotype in mice: Behavioural and biochemical evidence

ETHNOPHARMACOLOGICAL RELEVANCE Valeriana wallichii DC, an ayurvedic traditional medicine has now been shown to exist chemically as three distinct chemotypes. The study aimed to investigate the antidepressant effect of dichloromethane extract of Valeriana wallichii patchouli alcohol chemotype. MATERIALS AND METHODS Antidepressant effect of dichloromethane extract of Valeriana wallichii (10, 20 and 40mg/kg, p.o.) using forced swim test, was determined in both acute and chronic study. The neurotransmitter levels were estimated in mouse forebrain after two weeks of dosing. RESULTS Single administration of extract (40mg/kg) significantly inhibited the immobility period in mice (p<0.05). Similarly, chronic administration of extract (20 and 40mg/kg) significantly reduced the immobility period and significantly increased the levels of norepinephrine and dopamine in mouse forebrain (p<0.05). CONCLUSIONS The extract demonstrated antidepressant effect and significantly increased the norepinephrine and dopamine levels in forebrain.

Chemical composition and analgesic activity of Senecio rufinervis essential oil.

Context: Senecio rufinervis D.C (Asteraceae) is a tall aromatic herb, commonly found in Uttarakhand, India. No investigations on the biological activity of this plant have been published so far. Hence, this plant species became a subject of our scientific interest. Objective: The aim of the study was to investigate the chemical composition and analgesic activity of Senecio rufinervis essential oil in mice using both thermal and chemical models of pain. Materials and methods: Essential oil from dried leaves of Senecio rufinervis was extracted by steam distillation and then subjected to GC-MS analysis. Varying doses of essential oil were given to mice, 30 min prior to the induction of abdominal constrictions and determination of mean reaction time in hot-plate maintained at 55° ± 0.5°C. Results: The main component detected in the essential oil of Senecio rufinervis was germacrene D (40.19%) followed by β-pinene (12.23%), β-caryophyllene (6.21%) and β-longipinene (4.15%). Essential oil exhibited significant and dose-dependent analgesic activity against acetic acid-induced writhing in mice. The percentage inhibition in number of writhes produced by 25, 50 and 75 mg/kg doses was, respectively, 69, 80 and 85%. The oil, at doses 50 and 75 mg/kg, significantly increased the mean latency in the hot-plate after 15 and 30 min of drug administration as compared to the control group. Discussion and conclusion: The results depicted both central and peripheral analgesic activity of S. rufinervis essential oil which was attributed to the presence of terpenes.

Antidepressant-like action of the hydromethanolic flower extract of Tagetes erecta L. in mice and its possible mechanism of action

Objective: Tagetes erecta, the marigold, has commercial and ethnomedicinal use; however, reports concerning its efficacy for the treatment of depression are lacking. This study was carried out to elucidate the antidepressant effect of hydromethanolic flower extract of T. erecta. Materials and Methods: Hydromethanolic extract of flowers of Tagetes erecta was subjected to preliminary phytochemical screening. The extract (12.5, 25, and 50 mg/kg, i.p.) was evaluated for antidepressant effect using forced swim test in mice. The mechanism of antidepressant action was further examined using different drugs and imipramine was used as standard drug. Results: T. erecta significantly inhibited the immobility period in forced swim test in mice P<0.05). T. erecta (25 mg/kg, i.p.) enhanced the anti-immobility effect of antidepressant drugs like imipramine, fluoxetine, and p-chlorophenylalanine, an inhibitor of serotonin synthesis significantly attenuated its antidepressant effect. The antidepressant effect of T. erecta in the forced swim test was prevented by pretreatment with L-arginine and sildenafil, whereas pretreatment of mice with nitric oxide synthase inhibitors potentiated the action. Pentazocine, a high-affinity sigma receptor agonist, produced synergism with effective dose of T. erecta while progesterone, a sigma receptor antagonist, reversed the antidepressant effect of T. erecta. However, the locomotor activity was not affected at tested doses. Conclusions: Serotonergic, nitrergic pathway, and sigma receptors are possibly involved in mediating antidepressant action of T. erecta in mouse forced swim test.