Diffusates from the fungus-inoculated leaflets of Shuteria vestita have yielded four novel 3-hydroxyflavanone (dihydroflavonol) phytoalexins. From spectroscopic and chemical evidence, three of these phytoalexins have been identified as (2R,3R,2''R)--3,5,4'-trihydroxy-2'-isopropenyldihydrofurano (4'',5''; 6,7) flavanone (shuterol,1), (2R,3R)--3,5,7,4'-tetrahydroxy-6-(3,3-dimethylally) flavanone (shuterin, 2), and (2R,3R,2''R)--3,5,2',4'-tetrahydroxy-2''-isopropenyldihydrofurano (4'',5''; 6,7)flavanone (shuterone A, 3). The fourth compound (shuterone B, 4) is considered to be the 2S,3R stereoisomer of shuterone A.

Fabaceae↗

PubMedDate not supplied

Radioprotective and radiosensitizing effects of sulfur-containing amino acid derivatives on mice.

Both protection and sensitization of Mice C57Bl against 60Co gamma-rays by sulfur-containing amino acid derivatives--S-alkyl-L-cysteines, S-alkyl-2-methyl-DL-cysteines and their hydantoin derivatives, and sulfoxides of these compounds--were examined. DL-5 Allylthiomethyl-5-methylhydantoin (150 mg/kg body weight) had a remarkable radioprotective effect. The survival ratio was 4.3 or above two times as much as that of L-cysteine. On the other hand, its sulfoxide had a radiosensitizing effects; survival ratio, 0.333.

Amino Acids↗

PubMedDate not supplied

A new class of biflavonoids: 2'-hydroxygenistein dimers from the roots of white lupin.

Two novel isoflavonoid dimers presumably originating from 2'-hydroxygenistein, 5,7,4'-trihydroxycoumaranochroman-4-one-(3-->5"')-5",7",2"'4"'- tetrahydroxyisoflavone (1, lupinalbisone A) and 5,7,4'-trihydroxycoumaranochroman-4-one-(3-6")-5",7",2"',4"'-te trahydroxyisoflavone (2, lupinalbisone B) were isolated from the roots of Lupinus albus L., and their structures involving relative stereochemistry were elucidated by spectroscopic methods. Using horse radish peroxidase and 2'-hydroxygenistein (3) as the substrate revealed the formation of these dimers together with 5,7,4'-trihydroxycoumaronochromone (4, lupinalbin A). Dimerization of 3 caused a remarkable increase of antifungal activity.

Antifungal Agents↗

PubMedDate not supplied

Oxidative metabolism of ambrox and sclareolide by Botrytis cinerea.

Ambrox (1), a perfumery diterpene, was oxidatively metabolised by a plant pathogenic fungus Botrytis cinerea in a xenobiotic fashion to afford a major product, i.e., 1beta-hydroxy-8-epiambrox (13) (60%) along with three minor metabolites 3beta-hydroxyambrox (2), sclareolide (5) and 3beta-hydroxysclareolide (7). Sclareolide (5), a cytotoxic diterpenoidal lactone was fermented with the same fungus to yield 3beta-hydroxysclareolide (7) (59%) as a major metabolite together with two minor metabolites characterised as 1-ketosclareolide (15), and 3beta,14-dihydroxysclareolide (16).

Botrytis↗

PubMedDate not supplied

Biotransformation of two cytotoxic terpenes, alpha-santonin and sclareol by Botrytis cinerea.

Two cytotoxic terpenes, alpha-santonin (1) and sclareol (3) were biotransformed by a plant pathogenic fungus Botrytis cinerea to produce oxidized metabolites in high yields. Alpha-Santonin (1) on fermentation with the fungus for ten days afforded a hydroxylated metabolite identified as 11beta-hydroxy-alpha-santonin (2) in a high yield (83%), while sclareol (3) was metabolized to epoxysclareol (4) (64%) and a new compound 8-deoxy-14,15-dihydro-15-chloro-14-hydroxy-8,9-dehydrosclareol (5) (7%), representing a rare example of microbial halogenation.

Biotransformation↗

PubMedDate not supplied

Activation of isoflavone biosynthesis in excised cotyledons of Lupinus seedlings by jasmonoids and excess light.

Exogenous jasmonic acid (JA) and methyl jasmonate (MJ) induced accumulation of isoflavone constituents in cotyledons prepared from imbibed seeds of white lupin (Lupinus albus L.). Exogenous 0.2 mM MJ enhanced the levels of 7-O-(6"-O-malonyl)glucosylgenistein and 7-O-glucosylgenistein in the cotyledons of etiolated seedlings that had been incubated in the dark for 48 h. Regarding isoflavone induced by excision and slicing in the cotyledons as background level, the effect of light was 2- to 3-fold higher than that of 0.2 mM MJ. Cotyledons exposed to MJ along with a 24-h light period displayed a higher level of isoflavone accumulation than that of light alone. Total molar amounts of isoflavone accumulated in the cotyledons treated with MJ under continuous light were approximately the sum of those induced by MJ alone and light alone, respectively. The additive-like effect of MJ and light on isoflavone accumulation in lupin tissues suggested the presence of two different signaling systems independently responsible for those two stimuli. Excised cotyledons from etiolated yellow lupin (L. luteus L. cv. Topaz) seedlings also supported this hypothesis. The cotyledons could accumulate both an isoflavone and a flavone, and MJ selectively increased some of the isoflavone constituents, whereas light enhanced the levels of both. The selective accumulation mechanism of isoflavonoids in cotyledons, in which jasmonoids are involved, clearly differed from that activated by light.

Chromatography, High Pressure Liquid↗

PubMedDate not supplied

Repellent activity of estrogenic compounds toward zoospores of the phytopathogenic fungus Aphanomyces cochlioides.

Screening chemical compounds, we found that a xenoestrogen, bisphenol A, showed potent repellent activity against the zoospores of Aphanomyces cochlioides. Based on this finding, we tested a number of androgenic and estrogenic compounds (e.g. testosterone, progesterone, estradiols, diethylstilbestrol, estrone, estriol, pregnenolone, dienestrol etc.) on the motility behavior of A. cochlioides zoospores. Interestingly, most of the estrogenic compounds exhibited potent repellent activity (1 microg/ml or less by the "particle method") toward the motile zoospores of A. cochlioides. We derivatized some of the estrogens and discussed the relationship between the structure of active molecules and their repellent activity. Apparently, aromatization of the A ring with a free hydroxyl group at C-3 position of a steroidal structure is necessary for higher repellent activity. Interestingly, methylation of diethylstilbestrol (DES) yielded completely different activity i.e. both mono- and di-methyl ethers of DES showed attractant activity. Moreover, the attracted zoospores were encysted and then germinated in the presence of di-methyl ether of DES. The potential usefulness of this repellent test is discussed for the detection of estrogenic activity of naturally occurring compounds, and the possible role of phytoestrogens in host/parasite interactions. So far, this will be the first report of repellent activity of estrogenic compounds toward trivial fungal zoospores.

Antifungal Agents↗