Fermentation and antimicrobial activities of extracts from different species of fungus belonging to Genus, Trichoderma.

The present paper discusses the effects of the crude extracts of Trichoderma spp. on a number of fungal and bacterial organisms. These include Paecilomyces variotii, Penicillium notatum, Nematospora corylii, Mucor miehei, Bacillus brevis, Bacillus subtilis, Enterobacter dissolvens and Sarcina lutea. The culture broth extracts of different isolates of Trichoderma harzianum, T. longibrachiatum and T. koningii cultured in different media were investigated individually for in-vitro antifungal and antibacterial activities by agar diffusion technique. The culture broth extracts of T. harzianum produced definite antifungal and antibacterial activities against most of the test organisms. The results indicate that the extracts were fungicidal and antibacterial at a concentration of 100 microg per 6mm paper disks. Trichoderma harzianum showed the highest activity while T. koningii showed the least activity against most of the test organisms especially the yeast Nematospora coryli. The results of this study indicate that the Trichoderma species especially T. harzianum is a possible source of useful antimicrobial agents against pathogenic microorganisms which include gram-negative, gram-positive, fungi and yeasts.

Enhancement of the antiplasmodial activity of quassin by transformation into a gamma-lactone.

The naturally occurring bitter principle quassin (1) was converted chemically into the gamma-lactone quassilactone (13) in an attempt to enhance its antiplasmodial activity. The in vitro antiplasmodial activity of 13 against Plasmodium falciparum (K1) (IC(50) = 23 microM) was 40-fold greater than that of 1. However, one of the intermediates, compound 8, the 15beta-hydroxy,16-O-m-chlorobenzoyl analogue of 1, was 506-fold more active than 1 against P. falciparum (IC(50) = 1.8 microM) and only 3-fold less potent than chloroquine. In addition, 8 displayed the best cytotoxic/antiplasmodial ratio (112) of all of the compounds tested. In the course of this work a dimer, neoquassin ether (6), linked at C-16 was also prepared; 6 was found to have weak antiplasmodial activity (IC(50) = 9.7 microM).

A simple synthesis of 7,4'-dihydroxy-6-methoxyisoflavone, glycitein, the third soybean isoflavone.

4-Methoxyresorcinol (3) was synthesized as the precursor for glycitein (6) synthesis by the oxidation of 3-hydroxy-4-methoxybenzaldehyde (1) to the aryl formate with H2O2 and a catalytic amount of SeO2. Glycitein (6) was synthesized by cyclization of 2,4,4'-trihydroxy-5-methoxydeoxybenzoin (5) with N,N-dimethylformamide, boron trifluoride diethyl ether, and methanesulfonyl chloride in a microwave oven.

Flavonoids from Tephrosia aequilata.

From the roots of the plant Tephrosia aequilata Baker, five flavonoids were isolated of which, 3,4:8,9-dimethylenedioxypterocarpan is reported for the first time. Its structure and those of the already known flavonoids were established by physical and spectroscopic analysis. Application of 2D NMR techniques was useful for complete characterization of the new pterocarpan as well as the other known flavonoids.