Microbial reduction of ethyl acetoacetate using Sclerotium rolfsii

Summary A method for the quantitative enantioselective bioreduction of ethyl acetoacetate [1] to optically pure (+)-S-ethyl-3 hydroxybutyrate [II] usingSclerotium rolfsii mycelium is described. In a synthetic medium 1 g mycelium (dry weight) could convert 1 g of I to II within 2–3 days of fermentation (pH 5.8, 30°C). This is the first report demonstrating use ofS. rolfsii biomass for asymmetric reduction to get chiral building blocks.     

Siderophores of Cunninghamella blakesleeana NCIM 687

The fungus Cunninghamella blakesleeana NCIM 687, industrially recognized for progesterone biotransformation, was found to produce two siderophores at low stress of iron (upto 40 M iron in the growth medium). HPLC analysis and direct comparison with authentic samples characterized one of them as ferrichrysin (hydroxamate type) and other probably as a member of the coprogen family of siderophores.     

Hydroxylation of progesterone by Cunninghamella blakesleeana NCIM 687

Progesterone was completely hydroxylated, principally to 11,14 dihydroxyprogesterone by Cunninghamella blakesleeana NCIM 687 in 48h.S.B. Chincholkar is with the Microbiology Division, Department of Life Sciences, North Maharashtra University, Jalgaon 425 001, India. R. Seeta Laxman is with the Division of Biochemical Sciences, National Chemical Laboratory, Pune 411 008, India. R.D. Wakharkar is with Organic Chemistry. Technology Division, National Chemical Laboratory, Pune 411 008. India     

Sterculia guttata seeds extractives--an effective mosquito larvicide

The larvicidal activity of ethanol, chloroform and hexane soxhlet extracts obtained from S. guttata seeds was investigated against the IVth instar larvae of Dengue fever vector, Aedes aegypti and filarial vector, Culex quinquefasciatus. All extracts including fractions of ethanol extract exhibited 100% larval kill within 24 hr exposure period at 500 ppm concentration. Fraction A1 of ethanol was found to be most promising; its LC50 was 21.552 and 35.520 ppm against C. quinquefasciatus and A. aegypti respectively. Naturally occurring S. guttata seed derived fractions merit further study as potential mosquito larval control agents or lead compounds.     

Synthesis and biochemical evaluation of benzyl propargyl ethers as inhibitors of 5-lipoxygenase

A series of benzyl propargyl ethers were synthesized and tested as inhibitors of 5-lipoxygenase, the key enzyme involved in leukotriene biosynthesis. Among these, optimum activity was displayed by 1-(2-heptynyloxymethyl) benzene 12 (IC50 1.2 microM). Addition of carboxyl group at the end of the alkyl side chain attached to the acetylenic group abolished the inhibition. Selective reduction of the acetylenic group to cis or trans double bond reduced the inhibitory potential, the cis isomer 24 showing more than 20-fold higher inhibition than the trans isomer 25. Introduction of sulphur in place of oxygen in the alkyl side chain attached to the (carboxyalkyl) benzyl group also reduced the inhibition. The IC50 value of 12, towards rabbit reticulocyte 15-LOX is > 50 fold higher than that of 5-LOX. These results indicate that compound 12 is a specific inhibitor of 5-LOX.     

Fluconazole analogues containing 2H-1,4-benzothiazin-3(4H)-one or 2H-1,4-benzoxazin-3(4H)-one moieties,a novel class of anti-Candida agents

As a part of our program to develop new antifungal agents, a series of fluconazole analogues was designed and synthesized wherein one of the triazole moieties in fluconazole was replaced with 2H-1,4-benzothiazin-3(4H)-one or 2H-1,4-benzoxazin-3(4H)-one moiety. The new chemical entities thus synthesized were screened against various fungi and it was observed that the compounds 4a and 4i are potent inhibitors of Candida strains. The structure–activity relationship for these compounds is discussed.     

Larvicidal activity of bis(2-ethylhexyl) benzene-1,2-dicarboxylate from Sterculia guttata seeds against two mosquito species

The larvicidal activities of various fractions of the hexane extract of the seeds of Sterculia guttata against larvae of Aedes aegypti and Culex quinquefasciatus were determined. Bis(2-ethylhexyl) benzene-1,2-dicarboxylate (1) was identified as one of the active principles, displaying chronic toxicity against both types of larvae, with LD50 values of 79 and 64 ppm, respectively.