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Nootropic acitivity of calyces of Hibiscus sabdariffa Linn. was studied in mice. Elevated plus maze and passive avoidance paradigm were employed to evaluate learning and memory parameters. Scopolamine (0.4 mg/kg, i.p.) was used to induce amnesia in mice. The aqueous extracts of calyces of Hibiscus sabdariffa (HS-100 and 200 mg/kg, p.o.) significantly attenuated amnestic deficits induced by scopolamine (0.4 mg/kg, i.p.) and natural aging. HS (100 and 200 mg/kg) decreased the transfer latencies and increased step down latencies significantly in the aged mice and scopolamine induced amnesic mice as compared with Piracetam (200 mg/kg, i.p.). To delineate the possible mechanism through which H. sabdariffa elicits the anti-amnesic effects, we studied its influence on central cholinergic activity by estimating the whole brain acetylcholinesterase activity. H. sabdariffa significantly decreased acetyl cholinesterase activity in mice. The results indicate that, the aqueous extract of calyces of H. sabdariffa might prove to be a useful memory restorative agent in the treatment of dementia seen in elderly. The underlying mechanism of action can be attributed to its anti acetylcholinesterase property.

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As men get older, there is a decline in functioning of many biological systems; the endocrine systems share such changes in hormone levels. Ageing in men is accompanied by progressive, but individually variable decline in serum testosterone production in healthy men especially in men over 60 years of age. Androgens determine the differentiation of male internal and external genitalia as well as the development and maintain ace of male secondary sex characteristics and male reproductive function. They have important metabolic effects on protein, carbohydrate and fat metabolism and contribute to the determination of muscle mass and strength and also affect behavior and cognition. In ageing men, the serum androgen levels are affected due to several factors such as , circadian rhythmicity, heredity, body mass, diet, stress, life style, smoking, alcohol, and exercise. The decreased levels androgen may lead to senile osteroporosis, hypogonadism, decreased libido and brain functions. The incidence of cognitive disorders such as dementia and Alzheimer's disease is also high in testosterone deficient adults. The relationship between endogenous plasma testosterone levels, visual-spatial orientation, depression and brain function plays a vital role while treating aged males with cognitive disorders associated with decline in testosterone levels. The present paper highlights various aspects of ageing associated decline in androgen levels, cognitive function and usefulness and risk of androgen replacement therapy in aged males.