Nymphaea stellata Willd. (Syn. Nymphaea nouchali Burman f.) (Nymphaeaceae) is an important and well-known medicinal plant, widely used in the Ayurveda and Siddha systems of medicines for the treatment of diabetes, inflammation, liver disorders, urinary disorders, menorrhagia, blenorrhagia, menstruation problem, as an aphrodisiac, and as a bitter tonic. There seems to be an agreement between the traditional use and experimental observations, such as, hepatoprotective, anti-inflammatory, and particularly antidiabetic activity. Nymphayol, a steroid isolated from the flowers has been scientifically proved to be responsible for the traditionally claimed antidiabetic activity; it reverses the damaged endocrine tissue and stimulates secretion of insulin in the β-cells. However, taking into account the magnitude of its traditional uses, the studies conducted are still negligible. This review is an attempt to provide the pharmaceutical prospective of Nymphaea stellata.

Context: The roots of Aerva lanata Linn. (Amaranthaceae) (AL) are employed traditionally as an antihyperglycaemic in the Ayurvedic system of medicine. Objective: The present investigation is focus for identification and isolation of the bioactive compound from methanol roots extract of AL against streptozocin-nicotinamide induced elevated serum glucose level in rats. Materials and methods: The methanol extract of the roots was fractionated using different solvents. The partially purified alkaloid basified toluene fraction (PPABTF) showed the presence of alkaloids. The fraction (10 and 20 mg/kg) was tested for oral glucose tolerance test (OGTT) and in non-insulin-dependent diabetes mellitus (NIDDM)-induced elevated serum glucose level in rats. The fraction was also subjected to high performance thin layer chromatography (HPTLC) for the determination of content of individual alkaloids. Results: Single oral administration of PPABTF (10 and 20 mg/kg) after 20 h caused a significant (p < 0.01) reduction in the serum glucose level (mg/dl). On other hand, PPABTF normalised plasma glucose levels after 2 weeks of repeated oral administration in diabetic rats (p < 0.01). HPTLC analysis on PPABTF showed the presence of three known alkaloids. The fraction was further subjected to column chromatography and the compounds identified by ultraviolet, infrared, mass spectroscopy and nuclear magnetic resonance, as canthin-6-one derivatives. Conclusion and discussion: The PPABTF in the dose of 20 mg/kg showed significant effects on streptozotocin-nicotinamide induced type-II NIDDM in rats. The activity may be due to the presence of alkaloids like canthin-6-one derivatives.

People in Indian region often apply Shankhpushpi and other Sanskrit-based common name to Evolvulus alsinoides, Convolvulus pluricaulis, Canscora decussata, and Clitorea ternatea. These are pre-European names that are applied to a medicinal plant. Before the establishment of British rule, like the other books, ayurvedic treatises were also hand written. This might be one of the reasons due to which ayurveda could not stand parallel to the western medicine and an ambiguity is reflected in the interpretation of names and description of drugs found in the books like Charaka Samhita and Sushruta Samhita. The most widespread application of Shankhpushpi is for mental problems, but they have been considered for an array of other human maladies. The present investigation deals with the comparative pharmacognostical evaluation of four ethanobotanicals of Shankhpushpi. A comparative morphoanatomy of the root, stem, and leaves has been studied with the aim to aid pharmacognostic and taxonomic species identification. Various physicochemical, morphological, histological parameters, comparative high-performance thin-layer chromatography (HPTLC), and comparative high-performance liquid chromatography (HPLC), chromatogram of methanolic extract presented in this communication may serve the purpose of standard parameters to establish the authenticity of commercialized varieties and can possibly help to differentiate the drug from the other species. All the parameters were studied according to the WHO and pharmacopoeial guidelines.

Shankhpushpi is an Ayurvedic drug, widely used for its actions on the central nervous system, especially to improve intellect and boost memory. Four botanicals viz. Canscora decussata Schult. (CD), Clitorea ternatea Linn. (CT), Convolvulus pluricaulis Choisy. (CP) and Evolvulus alsinoides Linn. (EA) are considered as sources of Shankhpushpi by Indian practitioners on the basis of their morphological descriptions given in ancient texts. The present study was undertaken to evaluate the neuropharmacological effect of four herbs commonly identified as source of Shankhpushpi. Methanol extracts of all four varieties were tested and evaluated in vitro and in vivo for their neuropharmacological effects. Experiments such as protection against β-amyloid induced neurotoxicity on brain cell line (Neuro 2A), antioxidant potential, AchE (acetylcholinesterase enzyme) inhibition, and 5-LOX (lipoxygenase) enzyme inhibition were conducted for in vitro evaluation. For in vivo evaluation, scopolamine (0.3 mg/kg i.p.) induced memory retrieval using pole climbing apparatus and Morris water maze were performed in rat models. It was found that protective effects of EA and CD against β-amyloid induced neurotoxicity in Neuro 2A cells were significantly higher than CT and CP. EA proved to be superior than other varieties on the basis of antioxidant activity, AchE inhibitory and LOX inhibitory activities. The preventive activity of EA on scopolamine induced memory retrieval in pole climbing and Morris water maze task in rats was found to be higher than that of CD, CT and CP. EA has remarkable neuropharmacological effect as compared to other three varieties of Shankhpushpi. This effect may be attributed due to the presence of steroids (stigmasterol and betulinic acid), coumarins (scopoletin) and flavonoids (β-carotene and chlorogenic acid). Hence it can be used as a promising lead in development and management of neuronal disorders including Alzheimer's disease.