Effect of Nelumbo nucifera fruit on scopolamine induced memory deficits and motor coordination

Neuropharmacological Study on Capsaicin in Scopolamine-injected Mice

AIM

To evaluate the potential beneficial role of Capsaicin in cognitive dysfunction, mitochondrial impairment, and oxidative damage induced by scopolamine in mice.

BACKGROUND

Capsaicin is the chief phenolic component present in red chili and is responsible for its pungent and spicy flavor. It affects TRPV1 channels in nociceptive sensory neurons and is present in the hippocampus, and hypothalamus of the brains of rodents and humans.

OBJECTIVE

The main objective is to investigate the effective role of capsaicin in attenuating cognitive dysfunction, mitochondrial impairment, and oxidative damage induced by scopolamine in mice and examine the feasible mechanisms.

METHODS

Various doses of capsaicin (5, 10, and 20 mg/kg) were given orally to mice daily for 7 consecutive days after the administration of scopolamine. Various behavioral tests (motor coordination, locomotor counts, hole board test) and biochemical assay (Pro-inflammatory cytokines, catalase, lipid peroxidation, nitrite, reduced glutathione, and superoxide dismutase), mitochondrial complex (I, II, III, and IV) enzyme activities, and mitochondrial permeability transition were evaluated in the distinct regions of the brain.

RESULTS

Scopolamine-treated mice showed a considerable reduction in the entries and duration in the light zone as well as in open arms of the elevated plus maze. Interestingly, capsaicin at different doses reversed the anxiety, depressive-like behaviors, and learning and memory impairment effects of scopolamine. Scopolamine-administered mice demonstrated substantially increased pro-inflammatory cytokines levels, impaired mitochondrial enzyme complex activities, and increased oxidative damage compared to the normal control group. Capsaicin treatment reinstated the reduced lipid peroxidation, nitric oxide, catalase, superoxide dismutase, reduced glutathione activity, decreasing pro-inflammatory cytokines and restoring mitochondrial complex enzyme activities (I, II, III, and IV) as well as mitochondrial permeability. Moreover, the IL-1β level was restored at a dose of capsaicin (10 and 20 mg/kg) only. Capsaicin reduced the scopolamine-induced acetylcholinesterase activity, thereby raising the acetylcholine concentration in the hippocampal tissues of mice. Preservation of neuronal cell morphology was also confirmed by capsaicin in histological studies. From the above experimental results, capsaicin at a dose of 10 mg/kg, p.o. for seven consecutive days was found to be the most effective dose.

CONCLUSION

The experiential neuroprotective effect of capsaicin through the restoration of mitochondrial functions, antioxidant effects, and modulation of pro-inflammatory cytokines makes it a promising candidate for further drug development through clinical setup.

Evaluation of Antiinflammatory Activity of Ethanol Extract of Nelumbo nucifera Fruit

OBJECTIVES

In recent times, the use of natural remedies, which are rich in varieties of vitamins and flavonoids, for treatment of inflammation has increased substantially. These natural remedies are expected to be safe and economical when compared with other conventional allopathic drugs. Thus, existing research investigated the anti-inflammatory effect of Nelumbo nucifera fruit (NNF), in view of estimating its traditional and pharmacologic use against disorders associated with pain and inflammation.

MATERIALS AND METHODS

To estimate the antiinflammatory effect of NNF, carrageenan-induced paw edema method was employed with equally distributed (n=7) Wistar male rats (N=35). The paw edema was measured by volume displacement method with plethysmometer.

RESULTS

The NNF extract significantly reduced the inflammation of the paw and decreased the edema volume in rats administered carrageenan at all doses from the 3rd to 5th hour when compared to control, whose maximum percent reduction of edema was estimated as 100 mg/kg dose (that is, 73.92% at the 5th hour after administration of carrageenan).

CONCLUSION

NNF exhibited a strong antiinflammatory effect, due to its phytochemical constituents, including flavonoids, saponins, and tannins, all of which synergistically exert inhibitory effects on arachidonic acid metabolism, neutrophil degranulation, and enzyme systems that promote cell proliferation and regulation of complement system. However, more preclinical and clinical evaluations are mandatory to validate these findings.