Microbial transformation of mesterolone

The microbial transformation of mesterolone (= (1alpha,5alpha,17beta)-17-hydroxy-1-methylandrostan-3-one; 1), by a number of fungi yielded (1alpha,5alpha)-1-methylandrostane-3,17-dione (2), (1alpha,3beta,5alpha,17beta)-1-methylandrostane-3,17-diol (3), (5alpha)-1-methylandrost-1-ene-3,17-dione (4), (1alpha,5alpha,15alpha)-15-hydroxy-1-methylandrostane-3,17-dione (5), (1alpha,5alpha,6alpha,17beta)-6,17-dihydroxy-1-methylandrostan-3-one (6), (1alpha,5alpha,7alpha,17beta)-7,17-dihydroxy-1-methylandrostan-3-one (7), (1alpha,5alpha,11alpha,17beta)-11,17-dihydroxy-1-methylandrostan-3-one (8), (1alpha,5alpha,15alpha, 17beta)15,17-dihydroxy-1-methylandrostan-3-one (9), and (5alpha,15alpha,17beta)-15,17-dihydroxy-1-methylandrost-1-en-3-one (10). Metabolites 5-10 were found to be new compounds. All metabolites, except 2, 3, 6, and 7, exhibited potent anti-inflammatory activity. The structures of these metabolites were characterized on the basis of spectroscopic studies, and the structure of 5 was also determined by single-crystal X-ray-diffraction analysis.     

Eudesmane and megastigmane glucosides from Laggera alata

Four eudesmane glucosides, alatosides A-D (1-4), and one megastigmane glucoside, alatoside E (5), were isolated from the BuOH fraction of Laggera alata along with six known compounds. Structures of the new compounds were elucidated by a combination of chemical and spectroscopic methods. Alatosides A-E were characterized as: 1alpha-O-(beta-D-glucopyranosyloxyl)-7-epi-eudesma-11-en-2beta,4alpha-diol (1), 2beta-O-(beta-D-glucopyranosyloxyl)-eudesma-4alpha-hydroxyl-11(13)-en-12-oic-acid (2), 5beta-O-(beta-D-glucopyranosyloxyl)-eudesma-4(15),11(13)-dien-12-oic-acid (3), 5alpha-O-(beta-D-glucopyranosyloxyl)-eudesma-3,11(13)-dien-12-oic acid (4) and 3beta-O-(beta-D-glucopyranosyloxyl)-megastigma-9-one (5), respectively. Based on the chemical characteristics of eudesmane derivatives isolated from the Laggera genus, it was suggested that there are probably two different biogenetic pathways for these secondary metabolites in this genus.     

Microbial transformations of gelomulide G: a member of the rare class of diterpene lactones

Microbial transformation of gelomulide G (3beta,6beta-diacetoxy-8beta,14beta-epoxyabiet-13(15)-en-16,12-olide, 1) was carried out. Incubation of 1 with Aspergillus niger afforded two new metabolites, 3beta,6beta-diacetoxy-8beta,14beta-dihydroxyabiet-13(15)-en-16,12-olide (2) and 3beta,6beta-diacetoxy-14beta-hydroxyabieta-8(9),13(15)-dien-16,12-olide (3). While Cunninghamella elegans afforded the 14-epimer of 2, i.e., 3beta,6beta-diacetoxy-8beta,14alpha-dihydroxyabiet-13(15)-en-16,12-olide (4), along with 3beta-acetoxy-6beta-hydroxy-8beta,14beta-epoxyabiet-13(15)-en-16,12-olide (5). The structures of the transformed products 2-5 were deduced to be new on the basis of MS and NMR data.     

Chemical constituents of leaves and stem bark of Plumeria obtusa

The continued studies on the constituents of the fresh leaves and stem bark of Plumeria obtusa Linn. have led to the isolation and characterization of four new triterpenoids, dammara-12,20(22)Z-dien-3-one (1), dammara-12,20(22)Z-dien-3beta-ol (2), olean-12-en-3beta,27-diol (3), and 27-hydroxyolean-12-en-3-one (4) and 12 known compounds, which included eight triterpenoids; dammara-3beta,20(S),25-triol (5), urs-12-en-3beta-hydroxy-27-Z-feruloyloxy-28-oic acid (6), 3beta-hydroxyolean-12-en-28-oic acid (7), 3beta,27-dihydroxylupan-29-ene (8), 3beta-hydroxylupan-29-en-28-oic acid (9), 3beta-hydroxyursan-12-en-28-oic acid (11), 3beta-hydroxy-27-p-coumaroyloxy-olea-12-en-28-oic acid (12) and urs-12-en-3-one (15); an iridoid 1alpha-plumieride (10); a cardenolide 3alpha,14beta-dihydroxy-17beta-card-20(22)-enolide (13); a fatty acid ester methyl n-octadecanoate (14) and a steroid 3beta-hydroxy-delta5-stigmastane (16). The new constituents were characterized through spectroscopic studies including 1D (1H and 31C NMR) and 2D (COSY-45, NOESY, J-resolved, HMQC and HMBC) NMR and chemical transformations. This is the first report on the isolation of dammarane triterpenoids from P. obtusa. Compounds 5 and 6 are hitherto unreported from P. obtusa. The known compounds were identified by comparison of their spectral data with those reported in the literature.     

南海疏枝刺柳珊瑚中甾醇类化合物的研究

本文对采自海南三亚海域的疏枝刺柳珊瑚(Echinogorgia pseudossapo)化学成分进行研究,分离到11个甾醇类化合物。经波谱数据分析,分别鉴定为cholest-5-en-3β-ol(1),24-methylene-cholest-4-ene-3β,6β-diol(2),24-norcholesta-22-en-3β-ol(3),acanthovagasteroid A(4),calicoferol E(5),calicoferol F(6),6-hydroxy-cholest-4-ene-3-one(7),echinoflorasterol(8),echissaposterol(9),24-methylcholest-5-en-3β,7α-diol(10)和24-methylcholest-5,22(E)-dien-3β,7α-diol(11)。除化合物8外,其余化合物均首次从该种海洋动物中分离得到。     

Inhibitors of sterol synthesis. Chemical syntheses and spectral properties of 26-oxygenated derivatives of 3 beta-hydroxy-5 alpha-cholest-8(14)-en-15-one and their effects on 3-hydroxy-3-methylglutaryl coenzyme A reductase activity in CHO-K1 cells.

26-Oxygenated derivatives of delta 8(14)-15-ketosterols have been synthesized from (25R)-3 beta,26-diacetoxy-5 alpha-cholest-8(14)-en-15-one (IX) as part of a program to prepare potential metabolites and analogs of 3 beta-hydroxy-5 alpha-cholest-8(14)-en-15-one (I), a potent regulator of cholesterol metabolism. Partial hydrolysis of IX gave a mixture, from which the 3 beta,26-diol II and the 26-acetate (XI) and 3 beta-acetate (X) monoesters were isolated. Mitsunobu reaction of XI followed by hydrolysis gave (25R)-3 alpha,26-dihydroxy-5 alpha-cholest-8(14)-en-15-one (VI). Oxidation of XI with pyridinium chlorochromate followed by hydrolysis of the acetate gave (25R)-26-hydroxy-5 alpha-cholest-8(14)-ene-3,15-dione (VII). Oxidation of X with Jones reagent followed by hydrolysis of the acetate gave (25R)-3 beta-hydroxy-15-keto-5 alpha-cholest-8(14)-en-26-oic acid (IVa). Jones oxidation of II gave (25R)-3,15-diketo-5 alpha-cholest-8(14)-en-26-oic acid (VII). 1H and 13C nuclear magnetic resonance assignments and analyses of mass spectral fragmentation data are presented for each of the new compounds and their derivatives. The 3,15-diketone VII was found to be highly active in lowering the levels of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity in CHO-K1 cells, with a potency comparable to that of I. In contrast, 3 alpha,26-diol VI was less potent than I or VII. The two carboxylic acid analogs IVa and VIII were considerably less potent than VI in lowering the levels of HMG-CoA reductase activity.     

Studies of the oxysterol inhibition of tumor cell growth

The oxysterols 3 beta-hydroxy-5 alpha-cholest-8-en-11-one, 3 beta-hydroxy-5 alpha-cholest-8-en-7-one, 3 beta-hydroxy-5 alpha-cholest-8(14)-en-7-one, 3 beta-hydroxy-4,4'-dimethylcholest-5-ene-7 one, 4,4'-dimethylcholest-5-ene-3 beta, 7 alpha-diol, 4,4'-dimethylcholest-5-ene-3 beta, 7 beta-diol, lanost-8-ene-3 beta, 25-diol, 25-hydroxylanost-8-en-3-one, 9 alpha, 11 alpha-epoxy-5 alpha-cholest-7-en-3 beta-ol, 3 beta-hydroxycholest-5 alpha-en-22-one, and 3 beta-hydroxycholest-5-en-22-one oxime were evaluated with respect to their ability to inhibit cell growth. All of the sterols were found to possess cytotoxicity when incubated with hepatoma (HTC) and lymphoma (RDM-4) cells in culture at 10-30 microM concentrations.     

Base promoted air oxidation of 13beta-ethyl-11-methylenegon-4-en-17-one.

The structure of 13-ethyl-11-methylene-18,19-dinor-17alpha-pregn-4-en-20-yn-16beta,17-diol (3, 16beta-OH desogestrel), a by-product obtained in the last step of the synthesis of desogestrel (1) by reaction of monolithium acetylide-ethylenediamine complex with 13beta-ethyl-11-methylenegon-4-en-17-one (2), is here reported. The structural assignments were supported by NMR 1H-, 13C-, 1H-1H COSY, 1H-13C HSQC, COLOC) and mass spectroscopy, and the configuration at the C-16 and C-17 stereocentres was established by X-ray crystallography. When the same 17-ketoderivative 2 was treated with a non-alkylating base, such as potassium tert-butoxide, instead of the expected 16-hydroxylated ketone, a dimeric product, 13beta-ethyl-16-[2'-(des-D-13"-carboxy-13"beta-ethyl-11"-methylenegon-4"-en-14"-yl)-ethyliden]-11-methylenegon-4-en-17-one (4), was isolated in good yield; it was characterized by NMR, mass, ultraviolet spectroscopy, and chemical transformations. Compounds 3 and 4 originate from the high reactivity of the 16-methylenic position of the 17-keto substrate (2) toward molecular oxygen under basic conditions.     

Novel synthesis of cholesterol analogs: condensation of pregnenolone with dihydropyran or dihydrofuran.

Pregnenolone 3-(2'-tetrahydropyranyl) ether (1) was condensed with 3,4-[2H]dihydropyran to mainly give (20R)-[6'-(3',4'-[2'H]dihydropyranyl)]-pregn-5-ene-3 beta,20-diol 3-(2'-tetrahydropyranyl) ether (20R-3), according to nuclear magnetic resonance (NMR). Cold, dilute HCl in ethanol removed the tetrahydropyranyl group at C-3 and also opened the dihydropyranyl ring at the C-20 position of 20R-3 to give (20R)-27-norcholest-5-en-22-one-3 beta,20,26-triol (20R-5). Analogous results were obtained by condensing pregnenolone 3-acetate with 3,4-[2H]dihydropyran to provide (20R)-[6'-(3',4'-[2'H]dihydropyranyl)]-pregn-5-ene-3 beta,20-diol 3-acetate (20R-4). Acid-catalyzed opening of the dihydropyranyl ring at C-20 in 20R-4 yielded 20R-7, which, on acetylation followed by crystallization, provided (20R)-27-norcholest-5-en-22-one-3 beta,20,26-triol 3,26-diacetate (20R-8), identical to the diacetate made from 20R-5. Varying the reaction sequence beginning with 20(R,S)-4 gave an 84:16 ratio of 20R to 20S in a mixture of 20(R,S)-8, according to NMR analysis. Crystallization of the mixture from methanol provided pure 20R-8. Condensing 2,3-dihydrofuran and 1 for producing (20R)-[5'-(2',3'-dihydrofuranyl)]-pregn-5-ene-3 beta,20-diol 3-(2'-tetrahydropyranyl) ether (6) gave instead (20R)-26,27-bisnorcholest-5-en-22-one-3 beta,20,25-triol 3-(2'-tetrahydropyranyl) ether (20R-9) by partial hydrolysis during workup. Treating 20R-9 briefly with dilute HCl produced (20R)-26,27-bisnorcholest-5-en-22-one-3 beta,20,25-triol (20R-10).(ABSTRACT TRUNCATED AT 250 WORDS)     

Biotransformation of the antimelanoma agent betulinic acid by Bacillus megaterium ATCC 13368

Microbial transformation of the antimelanoma agent betulinic acid was studied. The main objective of this study was to utilize microorganisms as in vitro models to predict and prepare potential mammalian metabolites of this compound. Preparative-scale biotransformation with resting-cell suspensions of Bacillus megaterium ATCC 13368 resulted in the production of four metabolites, which were identified as 3-oxo-lup-20(29)-en-28-oic acid, 3-oxo-11alpha-hydroxy-lup-20(29)-en-28-oic acid, 1beta-hydroxy-3-oxo-lup-20(29)-en-28-oic acid, and 3beta,7beta, 15alpha-trihydroxy-lup-20(29)-en-28-oic acid based on nuclear magnetic resonance and high-resolution mass spectral analyses. In addition, the antimelanoma activities of these metabolites were evaluated with two human melanoma cell lines, Mel-1 (lymph node) and Mel-2 (pleural fluid).     

Steroidal saponins and cytoxicity of the wild edible vegetable-Smilacina atropurpurea

Four new steroidal saponins, smilacinoside A (1), B (2), C (3), and D (4), together with three known saponins, funkioside D (5), aspidistrin (6) and 26-O-beta-d-glucopyranosyl-22-methoxyl-(25R)-furost-5-en-3beta,26-diol 3-O-beta-d-glucopyranosyl-(1-->2)-beta-d-glucopyranosyl-(1-->4)-beta-d-galactopyranoside (7) were isolated from the dried tender aerial parts of Smilacina atropurpurea (Franch.) Wang et Tang. The structures of new compounds were elucidated as diosgenin 3-O-alpha-l-rhamnopyranosyl-(1-->2)-O-beta-d-galactopyranoside (1), diosgenin 3-O-alpha-l-rhamnopyranosyl-(1-->3)-[6-O-palmitoxyl]-O-beta-d-galactopyranoside (2), 26-O-beta-d-glucopyranosyl-(25R)-furost-5-en-3beta,22xi,26-triol 3-O-alpha-l-rhamnopyranosyl-(1-->2)}-beta-d-galactopyranoside (3) and 26-O-beta-d-glucopyranosyl-22-methoxyl-(25R)-furost-5-en-3beta,26-diol 3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-d-galactopyranoside (4) on the basis of chemical methods and detailed spectroscopic analysis, including 1D and 2D NMR techniques and single-crystal X-ray diffraction, respectively. Six of these compounds and MeOH extract were tested for their in vitro cytotoxicity toward K562 human tumor cells by an improved MTT method. Smilacinoside A, funkioside D and aspidistrin exhibited significant in vitro cytotoxicity against K562 with IC(50) values of 1.09, 2.93 and 0.47microg/mL, respectively.     

Diterpenoids and triterpenoids from Euphorbia guyoniana

Two new compounds with tigliane and cycloartane skeletons: 4,12-dideoxy(4alpha)phorbol-13-hexadecanoate (1) and 24-methylenecycloartane-3,28-diol (2), respectively, in addition of four known diterpenoids and 13 triterpenoids: 3-benzoyloxy-5,15-diacetoxy-9,14-dioxojatropha-6(17),11-diene (4), ent-abieta-8(14),13(15)-dien-16,12-olide (5), ent-8alpha,14alpha-epoxyabieta-11,13(15)-dien-16,12-olide (6), ent-3-hydroxyatis-16(17)-ene-2,14-dione (7), 3beta-hydroxytaraxer-14-en-28-oic acid (8), beta-sitosteryl-3beta-glucopyranoside-6'-O-palmitate (9), multiflorenyl acetate (10), multiflorenyl palmitate (11), peplusol (12), 24-methylenecycloartanol (3), lanosterol (13), euferol (14), butyrospermol (15), cycloartenol (16), obtusifoliol (17), cycloeucalenol (18) and beta-sitosterol (19), were isolated from the roots of Euphorbia guyoniana. Their structures were established on the basis of physical and spectroscopic analysis, including 1D and 2D homo- and heteronuclear NMR experiments (COSY, HSQC, HMBC and NOESY) and by comparison with the literature data.     

New 11(15-->1)abeotaxane, 11(15-->1),11(10-->9)bisabeotaxane and 3,11-cyclotaxanes from Taxus yunnanensis

Chemical examination of the seeds of Chinese yew, Taxus yunnanensis Cheng et L. K. Fu resulted in the isolation of an 11(15-->1)abeotaxane, an 11(15-->1), 11(10-->9)bisabeotaxane and two 3,11-cyclotaxanes. The structures of these new taxoids were established as 13alpha-acetoxy-5alpha-cinnamoyloxy-11(15-->1)abeotaxa-4(20),11-diene-9alpha,10beta,15-triol (1), 20-acetoxy-2alpha-benzoyloxy-4alpha, 5alpha, 7beta, 9alpha, 13alpha-pentahydroxy-11(15-->1), 11(10-->9) bisabeotax-11-eno-10,15-lactone (2), 2alpha,10beta-diacetoxy-5alpha-cinnamoyloxy-9alpha-hydroxy-3,11 -cyclotax-4(20)-en-13-one (3) and 10beta-acetoxy-2alpha,5alpha,9alpha-trihydroxy-3,11-cyclotax-4(20)-en-13-one (4) on the basis of spectral analyses.     

Antifungal highly oxygenated guaianolides and other constituents from Ajania fruticulosa.

Three highly oxygenated guaianolides were isolated from the aerial parts of Ajania fruticulosa along with 17 known phytochemicals including a triterpene (alpha-amyrin), two plant sterols (beta-sitosterol, daucosterol), four flavonoids (axillarin, centaureidin, santin and 5,7,4'-trihydroxy-3,3'-dimethoxyflavone), and ten sesquiterpenes [1alpha-hydroperoxy-4beta,8alpha,10alpha,13-tetrahydroxyguaia-2-en-12,6alpha-olide, 1alpha-hydroperoxy-4alpha,10alpha-dihydroxyguaia-9alpha-angeloyloxyguaia-2,11(13)-dien-12,6alpha-olide, 3beta,4alpha-dihydroxyguaia-11(13),10(14)-dien-12,6alpha-olide, 1alpha,4alpha,10alpha-trihydroxy-9alpha-angeloyloxyguaia-2,11(13)-dien-12,6alpha-olide, 1beta,2beta-epoxy-3beta,4alpha,10alpha-trihydroxy-guaia-11(13)-en-12,6alpha-olide and 2-oxo-8alpha-hydroxyguaia-1(10),3,11(13)-trien-12,6alpha-olide, ketoplenolide B, alantolactone, 9beta-hydroxyeudesma-4,11(13)-dien-12-oic acid and 9beta-acetoxyeudesma-4,11(13)-dien-12-oic acid]. The structures of the three guaianolides were elucidated by a combination of spectroscopic methods (EIMS, HREIMS, COSY, HMQC, HMBC and NOESY) as 1beta,2beta-epoxy-3beta,4alpha,8beta,10alpha-tetrahydroxyguaia-11(13)-en-12,6alpha-olide (1), 1beta,2beta-epoxy-3beta,4alpha,9alpha,10alpha-tetrahydroxyguaia-11(13)-en-12,6alpha-olide (2) and 1beta,2beta-epoxy-10alpha-hydroperoxy-3beta,4alpha,8beta-trihydroxyguaia-11(13)-en-12,6alpha-olide (3), respectively. Antifungal bioassay of all isolates showed that guaianolides 1, 2, 3, and 1beta,2beta-epoxy-3beta,4alpha,10alpha-trihydroxyguaia-11(13)-en-12,6alpha-olide were inhibitory to the growth of Candida albicans with MICs being 20, 20, 20, and 40 microg/ml, respectively.     

Steroid hydroxylation by Whetzelinia sclerotiorum, Phanerochaete chrysosporium and Mucor plumbeus

The fungi Whetzelinia sclerotiorum ATCC 18687, Phanerochaete chrysosporium ATCC 24725 and Mucor plumbeus ATCC 4740 were examined for their ability to perform steroid biotransformations under single phase, pulse feed conditions. The steroids 3beta-hydroxyandrost-5-en-17-one (dehydroepiandrosterone) (1), 17beta-hydroxyandrost-4-en-3-one (testosterone) (5), 3beta-hydroxypregn-5-en-20-one (pregnenolone) (3), pregn-4-ene-3,20-dione (progesterone) (9), 17alpha,21-dihydroxypregn-4-ene-3,11,20-trione (cortisone) (11), 17alpha,21-dihydroxypregna-1,4-diene-3,11,20-trione (prednisone) (14), and 3-hydroxyestra-1,3,5(10)-trien-17-one (estrone) (15) were fed to each fungus. The production of a number of novel metabolites is reported. Of the fungi investigated W. sclerotiorum performed the most interesting biotransformations and had a clear propensity for 2beta, 6beta/7beta and 15beta/16beta hydroxylations. P. chrysosporium was more prone functionalize steroids in the allylic position. Oxygen insertion at C-14 by M. plumbeus is reported for the first time. All three micro-organisms exhibited redox activity.     

Inhibitors of sterol synthesis. Chemical synthesis, structure, and biological activities of (25R)-3 beta,26-dihydroxy-5 alpha-cholest-8(14)-en-15-one, a metabolite of 3 beta-hydroxy-5 alpha-cholest-8(14)-en-15-one

3 beta-Hydroxy-5 alpha-cholest-8(14)-en-15-one (I) is a potent inhibitor of sterol synthesis with significant hypocholesterolemic activity. (25R)-3 beta,26-Dihydroxy-5 alpha-cholest-8(14)-en-15-one (II) has been shown to be a major metabolite of I after incubation with rat liver mitochondria. Described herein is the chemical synthesis of II from diosgenin. As part of this synthesis, improved conditions are described for the conversion of diosgenin to (25R)-26-hydroxycholesterol. Benzoylation of the latter compound gave (25R)-cholest-5-ene-3 beta,26-diol 3 beta,26-dibenzoate which, upon allylic bromination followed by dehydrobromination, gave (25R)-cholesta-5,7-diene-3 beta,26-diol 3 beta,26-dibenzoate. Hydrogenation-isomerization of the delta 5.7-3 beta,26-dibenzoate to (25R)-5 alpha-cholest-8(14)-ene-3 beta,26-diol 3 beta,26-bis(cyclohexanecarboxylate) followed by controlled oxidation with CrO3-dimethylpyrazole gave (25R)-3 beta,26-dihydroxy-5 alpha-cholest-8(14)-en-15-one 3 beta,26-bis(cyclohexanecarboxylate). Acid hydrolysis of the delta 8(14)-15-ketosteryl diester gave II. 13C NMR assignments are given for all synthetic intermediates and several major reaction byproducts. The structure of II was unequivocally established by X-ray crystal analysis. II was found to be highly active in the suppression of the levels of 3-hydroxy-3-methylglutaryl coenzyme A reductase in cultured mammalian cells and to inhibit oleoyl coenzyme A-dependent esterification of cholesterol in jejunal microsomes.     

Polyhydroxylated steroids from the soft coral Sinularia dissecta

A repeated silica gel column chromatography followed by HPLC purification on the methanol extract of marine soft coral Sinularia dissecta, resulted in the isolation of fifteen polyhydroxylated steroids (1-15), involving six new C-18 functionalized steroids, 3beta-acetoxy-1alpha,11alpha-dihydroxygorgost-5-en-18-oic acid (1), gorgost-5-en-1alpha,3beta,11alpha,18-tetrol (2), 18-acetoxy-1alpha,3beta,11alpha-trihydroxygorgost-5-ene (3), 24(S)-3beta-acetoxy-1alpha, 11alpha-dihydroxyergost-5-en-18-oic acid (4), 24(S)-ergost-5-en-1alpha,3beta,11alpha,18-tetrol (5), and dissectolide (6). The structures of the new compounds were determined on the basis of extensive spectroscopic data (IR, MS, (1)H and (13)C NMR, HMQC, HMBC, and NOESY) analysis. Compound 6 was found as an unusual sterol bearing a lactone functionality.     

Biotransformation of cadinane sesquiterpenes by Beauveria bassiana ATCC 7159

Incubation of cadina-4,10(15)-dien-3-one with Beauveria bassiana ATCC 7159 has resulted in the production of nine novel sesquiterpenes. These metabolites were identified as (4S)-cadin-10(15)-en-3-one, (4S)-3 alpha-hydroxycadin-10(15)-ene, (4R)-3 alpha-hydroxycadin-10(15)-ene, (4S)-3 beta-hydroxycadin-10(15)-ene, (4S)-3 beta-hydroxycadina-10(15),12(14)-diene, (4S)-13-hydroxycadin-10(15)-en-3-one, (4S)-12-hydroxycadin-10(15)-en-3-one, (4R)-3 beta, 14-dihydroxycadin-10(15)-ene and 3 alpha-hydroxycadina-4,10(15)-diene. The allylic alcohol 3 alpha-hydroxycadina-4,10(15)-diene was also biotransformed to afford cadina-4,10(15)-dien-3-one, (4S)-cadin-10(15)-en-3-one and (4S)-12-hydroxycadin-10(15)-en-3-one. The insecticidal potential and phytotoxicity of the isolated metabolites have been evaluated.     

Microbial metabolism of steviol and steviol-16alpha,17-epoxide

Steviol (2) possesses a blood glucose-lowering property. In order to produce potentially more- or less-active, toxic, or inactive metabolites compared to steviol (2), its microbial metabolism was investigated. Incubation of 2 with the microorganisms Bacillus megaterium ATCC 14581, Mucor recurvatus MR 36, and Aspergillus niger BCRC 32720 yielded one new metabolite, ent-7alpha,11beta,13-trihydroxykaur-16-en-19-oic acid (7), together with four known related biotransformation products, ent-7alpha,13-dihydroxykaur-16-en-19-oic acid (3), ent-13-hydroxykaur-16-en-19-alpha-d-glucopyranosyl ester (4), ent-13,16beta,17-trihydroxykauran-19-oic acid (5), and ent-13-hydroxy-7-ketokaur-16-en-19-oic acid (6). The preliminary testing of antihyperglycemic effects showed that 5 was more potent than the parent compound (2). Thus, the microbial metabolism of steviol-16alpha,17-epoxide (8) with M. recurvatus MR 36 was continued to produce higher amounts of 5 for future study of its action mechanism. Preparative-scale fermentation of 8 yielded 5, ent-11alpha,13,16alpha,17-tetrahydroxykauran-19-oic acid (10), ent-1beta,17-dihydroxy-16-ketobeyeran-19-oic acid (11), and ent-7alpha,17-dihydroxy-16-ketobeyeran-19-oic acid (13), together with three new metabolites: ent-13,16beta-dihydroxykauran-17-acetoxy-19-oic acid (9), ent-11beta,13-dihydroxy-16beta,17-epoxykauran-19-oic acid (12), and ent-11beta,13,16beta,17-tetrahydroxykauran-19-oic acid (14). The structures of the compounds were fully elucidated using 1D and 2D NMR spectroscopic techniques, as well as HRFABMS. In addition, a GRE (glucocorticoid responsive element)-mediated luciferase reporter assay was used to initially screen the compounds 3-5, and 7 as glucocorticoid agonists. Compounds 4, 5 and 7 showed significant effects.     

Microbial thansformation of a mixture of argentatin A and incanilin

The biotransformation of a mixture of argentatin A (20%) 1 and incanilin (80%) 2 by Gibberella suabinetti ATCC 20193 and Septomyxa affinis ATCC 6737 demonstrated the conversion of incanilin to 16beta-hydroxylanosta-2, 8, 23-triene, while argentatin A did not react. The acetate of this triterpenoid mixture was biotransformed by Septomyxa affinis ATCC 6737 to give five metabolites. Argentatin A acetate was transformed to 3beta, 16beta,30-trihydroxycycloart-20, 24-diene, 20R, 24R-epoxy-16beta, 25-dihydroxy-3, 4-seco-cycloart-4(28)-en-3-oic acid acetate and 20R, 24R-epoxy-16beta, 25-dihydroxy-3, 4-seco-cycloart-4(28)-en-3-oic acid. Incanilin acetate was converted to 16beta-hydroxylanosta-2, 8, 23-triene and 20R, 24R-epoxy-16beta, 25-dihydroxy-3, 4-seco-lanost-1, 4(28), 8-trien-3-oic acid acetate. The structural elucidations of these metabolites were achieved by different spectroscopic methods.