Iridoid biosynthesis in staphylinid rove beetles (Coleoptera: Staphylinidae, Philonthinae)

The biosynthesis of chrysomelidial and plagiodial was studied in the rove beetle subtribe Philonthina (Staphylinidae). Glandular homogenates were found to convert synthetic (2E,6E)-[trideuteromethyl-5,5-(2)H(5)]octa-2,6-diene-1,8-diol (10) into nor-chrysomelidial (14) and nor-plagiodial (13). The overall transformation requires; i) oxidation of the substrate at C(1) and C(8), ii) cyclization of the resulting dialdehyde to nor-plagiodial followed by iii) isomerization to give nor-chrysomelidial. The oxidase requires molecular oxygen as a cofactor and operates with removal of the pro-R hydrogen from C(1) and C(8) of synthetic (1R,8R,2E,6E)-[1,8-(2)H(2)]-2,6-dimethyl-octa-2,6-diene-1,8-diol (15), producing a dialdehyde along with H(2)O(2). Unlike enzymes from iridoid-producing leaf beetle larvae, the Philonthus enzyme is able to oxidize saturated substrates such as citronellol. Crude protein extracts prepared from Philonthus glands by ammonium sulfate precipitation, were found to produce hydrogen peroxide at a rate of 0.085+/-0.003 ng H(2)O(2) (ng protein)(-1) hr(-1) with nerol as an oxidase substrate. The cyclase operates with opposite stereochemistry to the enzyme(s) from Phaedon cochleariae and other herbivorous leaf beetles, specifically removing the C(5)-H(R) hydrogen atom from (4R,5S,2E,6E)-[4,5-(2)H(2)]-2-methyl-octa-2,6-diene-1,8-diol (17). These findings have enabled us to construct a detailed account of iridoid biosynthesis in rove beetles, which resembles the biosynthetic route in leaf beetle larvae, but exhibits distinct stereochemical differences.     

Constituents of the basidiomycete Scleroderma aurantium

The following compounds were isolated from the extract of the fresh peridium of Scleroderma aurantium: palmitic acid, linoleic acid, a mixture of triglycerides, an ester of a steroidal diol, ergosterol, ergosterol peroxide, 9(11)-dehydroergosterol peroxide, lanosta-8,23- dien-3β,25-diol, lanosta-8,24-diene-3β,23-diol, and mannitol.     

Isolation and structure characterization of two new diterpenoids from Clerodendrum bungei

Two new diterpenoids, 3β-(β-d-glucopyranosyl)isopimara-7,15-diene-11α,12α-diol (1), and 16-O-β-d-glucopyranosyl-3β-20-epoxy-3-hydroxyabieta-8,11,13-triene (2), along with three known ones were isolated from the roots of Clerodendrum bungei. These compounds were purified, and their structures were elucidated by extensive spectroscopic analyses, especially 2D NMR experiments. All compounds were evaluated for cytotoxicity against several tumor cell lines.     

Teucretol,a neo-clerodane diterpenoid from Teucrium creticum

From the aerial parts of Teucrium creticum a new neo-clerodane diterpenoid, teucretol, has been isolated, together with the previously known diterpenoids 6,19- diacetylteumassilin, 19-acetylgnaphalin and teucjaponin B. The structure of teucretol, 6,19-diacetoxy-4α,18;15,16-diepoxy-neo-cleroda-13(16),14-diene-12ξ,20-diol, was established by chemical and spectroscopic means.     

Diterpenoids from the stems of Tripterygium hypoglaucum (Celastraceae) and cytotoxic evaluation

Four new diterpenoids, 2α,16α-hydroxy-ent-kauran-19,20-olide (1), isopimara-8(14),15-diene-11β,19-diol (2), isopimara-8(14),15-diene-12α,19-diol (3), and 3-oxo-14,15-dihydroxyabieta-8,11,13-trien-19-ol (4), along with seven known compounds (5–11) were isolated from Tripterygium hypoglaucum. Their structures were established on the basis of extensive spectroscopic analysis. Triptolide (5) and 2-epitripdiolide (6) showed significant cytotoxicity against A549, DU145, KB, KBvin and MDA-MB-231 cell lines with IC₅₀ values of 0.0012–0.1306 μM in vitro.     

Monoterpene biotransformation by <Emphasis Type="Italic">Colletotrichum</Emphasis> species

Objective

To investigate the biocatalytic potential of Colletotrichum acutatum and Colletotrichum nymphaeae for monoterpene biotransformation.

Results

C. acutatum and C. nymphaeae used limonene, α-pinene, β-pinene, farnesene, citronellol, linalool, geraniol, perillyl alcohol, and carveol as sole carbon and energy sources. Both species biotransformed limonene and linalool, accumulating limonene-1,2-diol and linalool oxides, respectively. α-Pinene was only biotransformed by C. nymphaeae producing campholenic aldehyde, pinanone and verbenone. The biotransformation of limonene by C. nymphaeae yielded 3.34–4.01 g limonene-1,2-diol l^?1, depending on the substrate (R-(+)-limonene, S-(?)-limonene or citrus terpene (an agro-industrial by-product). This is among the highest concentrations already reported for this product.

Conclusions

This is the first report on the biotransformation of these terpenes by Colletotrichum spp. and the biotransformation of limonene to limonene-1,2-diol possibly involves enzymes similar to those found in Grosmannia clavigera.

     

New monoterpenoid by biotransformation of thymoquinone using Aspergillus niger

Microbial transformation of thymoquinone (5-isopropyl-2-methyl-cyclohexa-2,5-diene-1,4-dione) (1) by suspended cell-cultures of the plant pathogenic fungus Aspergillus niger resulted in the production of three metabolites. These metabolites were identified as 5-isopropyl-2-methyloxepin-1-one (2), 3-hydroxy-5-isopropyl-2-methylcyclohexa-2,5-diene-1,4-dione (3), and 5-isopropyl-2-methylbenzene-1,4-diol (4) by different spectroscopic methods. Metabolite 2 was found to be a new compound. Compound 4 showed a potent antioxidant activity.     

The synergistic attractiveness effect of plant volatiles to sex pheromones in a moth

The effects of plant-derived chemicals (volatiles) on the attraction of the Spodoptera litura moth to sex pheromones were evaluated using an electroantennogram (EAG). Neuronal responses of male moths to sex pheromone mixtures (SPs) (a 9:1 mixture of synthetic (9Z,11E)-9,11-tetraddecadienyl acetate (Z9E11-14:OAc) and (9Z,12E)-9,12-tetradecadienyl acetate (Z9E12-14:OAc)) and to SPs mixtures with eight plant volatiles (benzaldehyde, (E)-β-caryophyllene, phenylacetaldehyde, 2,6-nonadienal, benzyl alcohol, racemic linalool, longifolene, and (E)-β-ocimene) were also measured. Then, wind tunnels and field trapping bioassays were conducted to determine the influence of plant volatiles on S. litura moth behavioral responses to SPs. The results indicated that benzaldehyde, phenylacetaldehyde, and benzyl alcohol significantly enhanced, and longifolene, (E)-β-caryophyllene, and (E)-β-ocimene had no significant effect on the attractions to SPs, whereas racemic linalool significantly decreased the attraction of male S. litura moths to SPs throughout the olfactory pathway. 2,6-Nonadienal significantly enhanced olfactory responses, but had no significant effect on output behavior. These findings provide foundations in utilization of plant volatiles and sex pheromones to manage the pest and other agricultural pests.     

Sterols of Agarum cribosum: desmosterol in a brown alga

The sterol composition of the cold water brown alga Agarum cribosum was determined by GC—MS. Six of the seven sterols found were identified as stigmata-5,(E)-24(28)-dien-3β-ol (fucosterol), 24-methylenecholest-5-en-3β-ol (24-methylenecholesterol), cholest-5-en-3β-ol (cholesterol), 3β-hydroxycholest-5-en-24-one (24-ketocholesterol), 24ξ-stigmasta-5,28-diene-3β,24-diol (saringosterol) and cholesta-5, 24-dien-3β-ol (desmosterol).     

Acacidiol,a new nor-triterpene from the sapogenins of Acacia concinna

From the neutral fraction of the acid hydrolysate of the saponin of Acacia concinna pods, acacic acid lactone 3β-acetate and a new nor-triterpene ‘acacidiol’ have been isolated. The latter is shown to be 28-noroleana-16,18-diene-3β,21β-diol.     

Four new lanostane-type triterpenoids from Inonotus obliquus

Four new lanostane-type triterpenoids, inonotsuoxodiol B (1), inonotsuoxodiol C (2), epoxyinonotsudiol (3), and methoxyinonotsutriol (4), were isolated from the sclerotia of Inonotus obliquus. Their structures were determined to be 3β,22R-dihydroxylanosta-9(11),24-dien-7-one (1), 3β,22R-dihydroxylanosta-7,24-dien-11-one (2), 9α,11α-epoxy-lanosta-7,24-diene-3β,22R-diol (3), and 7β-methoxylanosta-8,24-diene-3β,11α,22R-triol (4) on the basis of NMR spectroscopy, including 1D and 2D (¹H–¹H-COSY, NOESY, HMQC, HMBC) NMR spectra, and EIMS.     

Lanostane-triterpenoids from the fungus Phellinus gilvus

Triterpenoids gilvsins A-D (1-4), with oxygenated lanostane skeletons, were isolated from the fruiting body of Phellinus gilvus, together with two known compounds, 24-methylenelanost-8-ene-3β, 22-diol and 5α-ergosta-7,22-diene-3-one. The structures of 1-4 were deduced from analysis of spectroscopic data. The absolute configuration at C-22 of 1 was determined by the modified Mosher’s method and the structure of 1 was confirmed by X-ray analysis. The hypoglycemic activities of the crude extract of P. gilvus and the isolated compounds were also evaluated, but were not promising for further investigation.     

Biosynthetic relationship of citral-trans and citral-cis in cymbopogon flexuosus (lemongrass)

Use of [¹⁴C,³H]-labelled precursors revealed that leaf blades of Cymbopogon flexuosus converted geraniol (3,7-dimethylocta-trans-2,6-diene-1-ol) into citral-trans with loss of pro-(1S) hydrogen whereas nerol lost the pro-(1R) hydrogen while being converted into citral-cis. Secondly, the citral-trans is converted into citral-cis and vice versa and there is no separate route for the biosynthesis of either of the two aldehyde isomers.     

Selective fraction of Atractylodes lancea (Thunb.) DC. and its growth inhibitory effect on human gastric cancer cells

The purpose of this study was to investigate the pharmacological effect of fraction of Atractylodes lancea (Thunb.) DC. (A. lancea) extract. In this study, we isolated different polarity fractions, including petroleum ether (PE), ethyl acetate, n-butanol, and the remaining H₂O fractions from the water extract of A. lancea. The antigastric cancer properties of the different fractions in BGC-823 and SGC-7901 cells were evaluated. Apoptotic cells were treated with PE fraction and stained with Hoechst 33342 and 5,5,6,6-tetrachloro-1,1,3,3-tetraethylbenzimidazolylcarbocyanine iodide. The cell cycle was analyzed via flow cytometry. The main compounds of PE fraction were determined by HPLC–ESI–MS. Results of this study showed that the PE fraction of A. lancea inhibited the growth of BGC-823 and SGC-7901 cells in a dose- and time-dependent manner. The morphological and mitochondrial transmembrane potential changes suggested that the cells showed preliminary apoptosis characteristics after treatment with the three different polarities. The main compounds of PE fraction include two sesquiterpene compounds: eudesm-4(15),7-diene-9α,11-diol and eudesm-4(15)-ene-7a,11-diol; three sesquiterpene lactone compounds: atractylenolid I, atractylenolid III and 3-β-acetyl-atractylenolid III and one polyacetylenic compound: 4,6,12-tetradecatriene-8,10-diyne-1,3,14-triol.     

Biodegradation of polyfluorinated biphenyl in bacteria

Fluorinated aromatic compounds are significant environmental pollutants, and microorganisms play important roles in their biodegradation. The effect of fluorine substitution on the transformation of fluorobiphenyl in two bacteria was investigated. Pseudomonas pseudoalcaligenes KF707 and Burkholderia xenovorans LB400 used 2,3,4,5,6-pentafluorobiphenyl and 4,4??-difluorobiphenyl as sole sources of carbon and energy. The catabolism of the fluorinated compounds was examined by gas chromatography?Cmass spectrometry and fluorine-19 nuclear magnetic resonance spectroscopy (¹⁹F NMR), and revealed that the bacteria employed the upper pathway of biphenyl catabolism to degrade these xenobiotics. The novel fluorometabolites 3-pentafluorophenyl-cyclohexa-3,5-diene-1,2-diol and 3-pentafluorophenyl-benzene-1,2-diol were detected in the supernatants of biphenyl-grown resting cells incubated with 2,3,4,5,6-pentafluorobiphenyl, most likely as a consequence of the actions of BphA and BphB. 4-Fluorobenzoate was detected in cultures incubated with 4,4??-difluorobiphenyl and ¹⁹F NMR analysis of the supernatant from P. pseudoalcaligenes KF707 revealed the presence of additional water-soluble fluorometabolites.     

Oxidation of 2-(2-bromoethyl)bromobenzene with toluene dioxygenase: Isolation and identification of new chiral synthons

2(2-Bromoethyl)bromobenzene was subjected to microbial oxidation by the whole cells of Pseudomonas putida 39/D and JM109(pDTG601) yielding (3R,4S)-2-(2-bromoethyl)-bromocyclohexa-1,5-diene-3,4-diol. © 1995 Wiley-Liss, Inc.     

Beilschglabrines A and B: Two new bioactive phenanthrene alkaloids from the stem bark of Beilschmiedia glabra

Two new phenanthrene alkaloids, beilschglabrines A (1) and B (2) were isolated from the stem bark of Beilschmiedia glabra, together with lupeol, taraxerol, and 24-methylenelanosta-7,9-diene-3β-15α-diol. The structures of the isolated compounds were elucidated by extensive spectroscopic data analysis and comparison with respective literature data. The compounds were tested for DPPH radical scavenging, acetylcholinesterase and lipoxygenase inhibitory activities. Compound 1 displayed considerable activity in the acetylcholinesterase (IC₅₀ 50.4 μM), the DPPH radical scavenging (IC₅₀ 115.9 μM) and the lipoxygenase (IC₅₀ 32.8 μM) assays.     

Physiological and Chemical Investigations into Microbial Degradation of Synthetic Poly(cis-1,4-isoprene)

Streptomyces coelicolor 1A and Pseudomonas citronellolis were able to degrade synthetic high-molecular-weight poly(cis-1,4-isoprene) and vulcanized natural rubber. Growth on the polymers was poor but significantly greater than that of the nondegrading strain Streptomyces lividans 1326 (control). Measurement of the molecular weight distribution of the polymer before and after degradation showed a time-dependent increase in low-molecular-weight polymer molecules for S. coelicolor 1A and P. citronellolis, whereas the molecular weight distribution for the control (S. lividans 1326) remained almost constant. Three degradation products were isolated from the culture fluid of S. coelicolor 1A grown on vulcanized rubber and were identified as (6Z)-2,6-dimethyl-10-oxo-undec-6-enoic acid, (5Z)-6-methyl-undec-5-ene-2,9-dione, and (5Z,9Z)-6,10-dimethyl-pentadec-5,9-diene-2,13-dione. An oxidative pathway from poly(cis-1,4-isoprene) to methyl-branched diketones is proposed. It includes (i) oxidation of an aldehyde intermediate to a carboxylic acid, (ii) one cycle of β-oxidation, (iii) oxidation of the conjugated double bond resulting in a β-keto acid, and (iv) decarboxylation.     

Bioconversion of citronellol by Botrytis cinerea

Summary Bioconversion of citronellol 1 was studied with four strains of Botrytis cinerea. Using grape must predominant transformation of 1 to 2,6-dimethyl-1,8-octandiol 2 and (E)-2,6-dimethyl-2-octen-1,8-diol 3 was observed. In minor amounts 2,6-dimethyl-2,8-octandiol 4, two p-menthan-3,8-diol isomers 5a, 5b, (Z)-2,6-dimethyl-2-octen-1,8-diol 6, isopulegol 7, 2-methyl-2-hepten-6-one-1-ol 8 and 2-methyl--butyrolactone 9 were found. Using a small amount of grape must in a synthetic medium (1:700) the bioconversion products 2, 4, 5a and 5b were absent, but additionally 2-methyl-2-hepten-6-one 10, 2-methyl-2-hepten-6-ol 11 and citronellic acid 12 were detected. The results obtained were strongly dependent on the strains used; one strain did not show any metabolic activity against 1. The bioconversion products were identified by capillary gas chromatography (HRGC) and coupled HRGC techniques, i.e. on-line — mass spectrometry (HRGC-MS) and — Fourier transform infrared spectroscopy (HRGC-FTIR).