Persistency of tylophorine as an insect antifeedant againstSpilosoma obliqua walker

Selective interaction between tylophorine B and bulged DNA

Tylophorine B exhibits pronounced cytotoxicity and antitumor activity. In order to survey the structure selectivity to DNA afforded by tylophorine B, we have synthesized a variety of duplex, bulge- and hairpin-containing oligodeoxyribonucleotides. Their binding to tylophorine B has been assayed by fluorescence spectroscopy and thermal melting experiments. The results indicate that oligonucleotides interact with tylophorine B at submicromolar concentration, and the affinity for DNA bulge is optimal (with Kd of 0.018 microM). In addition, the bulged hairpin oligonucleotides are stabilized by binding to tylophorine B. These findings may shed some light on tylophorine B's mode of action in biological systems and result in the rational design of sequence-specific DNA binding molecules.

Antifeedant and antifungal activity of chromene compounds isolated from Blepharispermum subsessile

Desmethyl isoencecalin and 5-hydroxy-6-acetyl-2-hydroxymethyl-2-methyl chromene isolated from Blepharispermum subsessile rhizomes were shown to have antifeedant activity against larvae of Spilarctia obliqua and also antifungal activity against Candida albicans and Cryptococcus neoformans (MIC 25-250 microg/ml).

Persistency of bioactive fractions of Indian plant, Polygonum hydropiper as an insect feeding deterrent

An improved extraction procedure resulted into a six-fold yield of bioactive fraction than the usual extraction method with a high per cent of feeding deterrence against 3rd instar larvae of Spilarctia obliqua and Spodoptera litura. The effective concentration (EC50) of PH-2 was 4321 and 4155 ppm against the two insects. No loss in feeding deterrency was recorded when the bioactive ether fraction, PH-2 was exposed to sunlight for 6 h.

Natural products of commercial potential as medicines

Recent advances in research on natural products (of both low and high molecular weight) of plant origin and their commercial potential as medicines are discussed. Substances with immunomodulating, antiviral, antimicrobial, antiparasite, antitumor, anti-inflammatory, hypoglycemic, tranquillizer and antifeedant activities are focused on.