Studies were carried out to determine the phytochemical and antimicrobial properties of various parts of Muntingia calabura L. Aqueous and methanol extracts of leaf, bark and fruits were prepared and phytochemical analysis of the parts revealed the presence of glycosides and flavonoids as the major biologically active compounds. Bacterial isolates of clinical importance and fungal phytopathogens were tested against the various extracts of M. calabura. Various degree of inhibition was observed with various extracts and significant antibacterial activity was recorded against Micrococcus luteus, Pseudomonas aeruginosa and Bacillus cereus. Antifungal activity of the methanol extracts were seen against Fusarium sp and Penicillium sp and was mainly due to the presence of tannins. Nil antifungal activity of aqueous extract was described in the study due to the absence of bioactive compounds in the extracts. The presence of glycosides, tannins and flavonoids has influenced the antimicrobial properties of the plant especially against M. luteus and P. aeruginosa. Methanolic extracts have shown better efficacy against the test isolates than the aqueous extracts throughout the study revealing the soluble nature of the phytochemicals in the solvent. The broad antimicrobial activity suggests the use of M. calabura as a source of new bioactive principles for the development of drugs against human and plant pathogens.

We have prepared anti,cisoid-alternating oligosilanes up to Si22 comprising bis(tetramethylene)-tethered bicyclic disilane units end-capped with n-alkyldimethylsilyl groups to measure their UV absorption and MALDI-TOF mass spectra. It was confirmed that the absorption maximum wavelength due to the σσ* transition remains constant in the present anti,cisoid-alternating oligosilanes irrespective of elongation of the chain length, providing the generality of the suppression effect of σ-conjugation by a cisoid turn.

The synthesis of some biologically interesting isoxazolidine derivatives has been accomplished by the cycloaddition reaction of C-(4-biphenyl)-N-(3-methylphenyl) nitrone and C-(4-biphenyl)-N-(3-chlorophenyl) nitrone to monosubstituted alkenes. The compounds were screened for their antibacterial and antifungal activities. Among the tested compounds 3a (ii), 3a (vii), 3a (viii), 3b (iv), 3b (vii), and 3b (viii) showed significant antifungal activity comparable with that of the standard drug Nystatin against Botrydiplodia theobromae.

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