Neem (Azadirachta indica A. Juss.) has universally been accepted as a wonder tree because of its diverse utility. Multidirectional therapeutic uses of neem have been known in India since the Vedic times. Besides its therapeutic efficacies, neem has already established its potential as a source of naturally occurring insecticide, pesticide and agrochemicals. Safe and economically cheaper uses of different parts of neem in the treatment of various diseases and in agriculture are discussed in this article. It further deals with the active chemical constituents of various neem formulations. Commercially available neem products are also mentioned along with their respective applications. Furthermore, evaluation of safety aspects of different parts of neem and neem compounds along with commercial formulations are also taken into consideration. Systematic scientific knowledge on neem reported so far is thus very useful for the wider interests of the world community.

A simple, straightforward, and highly efficient multicomponent one-pot synthesis of a pharmaceutically interesting diverse kind of functionalized 2-amino-3-cyano-4H-pyrans and pyran-annulated heterocycles has been developed based on a low-cost and environmentally benign commercially available urea as a novel organo-catalyst. The reaction occurs via tandem Knoevenagel–cyclocondensation of aldehydes, malononitrile, and C–H-activated acidic compounds in aqueous ethanol at room temperature. Following this protocol, it was possible to synthesize 2-amino-3-cyano-pyrano­[3,2-c]­chromen-5­(4H)-ones (4aa–4al), 2-amino-3-cyano-pyrano­[4,3-b]­pyran-5­(4H)-ones (4ba–4be), 2-amino-3-cyano-7,8-dihydro-4H-chromen-5­(6H)-one (4ca–4cr), 1H-pyrano­[2,3-d]­pyrimidine-2,4­(3H,5H)-diones (4da–4dd), 2-amino-3-cyano-5,10-dioxo-5,10-dihydro-4H-benzo­[g]­chromenes (4ea–4ec), 2-amino-3-cyano-4H-pyrans (4fa–4fh), and 1,4-dihydropyrano­[2,3-c]­pyrazoles (4ga–4gb). The salient features of the present protocol are mild reaction conditions, excellent yields, high atom-economy, eco-friendly standards, easy isolation of products, no column chromatographic separation, and reusability of reaction media. Bis-pyranization has also been observed in the reactions of terephthaldehyde.

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Stevioside, an ent-kaurene type of diterpenoid glycoside, is a natural sweetener extracted from leaves of Stevia rebaudiana (Bertoni) Bertoni. Stevioside and a few related compounds are regarded as the most common active principles of the plant. Such phytochemicals have not only been established as non-caloric sweeteners, but reported to exhibit some other pharmacological activities also. In this article, natural distribution of stevioside and related compounds, their structural features, plausible biosynthetic pathways along with an insight into the structure-sweetness relationship are presented. Besides, the pharmacokinetics, wide-range of pharmacological potentials, safety evaluation and clinical trials of these ent-kaurene glycosides are revisited.

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