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At least 19 recordsLinked to original sources
PubMed1995

Oxidation and glucose conjugation of synthetic abietane diterpenes by Cunninghamella sp. II. Novel routes to the family of diterpenes from Tripterygium wilfordii.

Abietane diterpenes from the perennial herb, Tripterygium wilfordii, have been shown to possess antiinflammatory activity. To obtain novel analogues of these diterpenes, two synthetic diterpenes, isotriptophenolide [1] (12,19-dihydroxy-18(4-->3)abeo-abieta-3,8,11,13-tetraen++ +-18-oic acid lactone) and triptophenolide [3] (14,19-dihydroxy-18(4-->3)abeo-abieta-3,8,11,13-tetraen++ +-18-oic acid lactone) were incubated with the filamentous fungi, Cunningbamella echinulata and C. elegans. The structures of the metabolites were then determined by spectroscopic methods. Both species of Cunninghamella glucosidated 1 at C-12 to yield 2. When incubated with triptophenolide [3], C. elegans and C. echinulata produced hydroxylated [6] and glucosylated [7] metabolites. In addition to B-ring hydroxylation, aromatic hydroxylation at ring C was also observed. Both species hydroxylated 3 to yield the dihydrodiol 4 which autooxidized to the quinone 5.

Biotransformation↗
PubMed1999

Response of abietane diterpenes to stress in Rosmarinus officinalis L.: new insights into the function of diterpenes in plants.

Abietane diterpenes were measured in field-grown rosemary (Rosmarinus officinalis L.) plants throughout the year. Carnosic acid and carnosol, which were present in high amounts (5 and 1 mg/gDW respectively) in rosemary leaves, decreased by ca. 50% during the Mediterranean summer in response to low precipitation, high radiation and high temperature. In contrast, the highly oxidised diterpenes rosmanol, isorosmanol and dimethyl isorosmanol, which are formed from carnosic acid by enzymatic dehydrogenation and the action of activated oxygen, increased in response to such environmental constraints. Collectively, these data support the contention that abietane diterpenes from R. officinalis function as antioxidants that protect biological membranes from oxidative stress. This is especially important during the Mediterranean summer when there is low precipitation, high light and high temperature.

Abietanes↗
PubMed2006

Cembranoid diterpenes and a briarane diterpene from corals.

Two new cembrane diterpenes (+)-polydactylide (1) and (+)-7alpha,8beta-dihydroxydeepoxysarcophine (2) together with (+)-sarcophine (3) and (+)-sarcophytoxide (4) have been isolated from the soft coral Sinularia polydactyla. The new cembrane diterpene (-)-7beta-hydroxy-8alpha-methoxydeepoxysarcophine (5) has been obtained from the soft coral Sarcophyton trocheliophorum and the known briarane diterpene briaexcavatolide W (6) from the gorgonian coral Briareum sp.The structures were determined primarily by NMR spectroscopy. The assignment of NMR signals was performed by means of (1)H-(1)H COSY, ROESY, HMQC and HMBC experiments.

Animals↗
PubMed2006

Salvidorol, a nor-abietane diterpene with a rare carbon skeleton and two abietane diterpene derivatives from Salvia dorrii.

Salvidorol (1), a irregular nor-abietane-type diterpene, was isolated from the aerial parts of Salvia dorrii, in addition to two epimeric abietane diterpenes (2 and 3). This is the first report of a nor-diterpene with an irregular skeleton. The structures were established by high-field NMR techniques ((1)H-(1)H COSY, DEPT, HMQC, HMBC, NOESY and HRMS) and in case of 2 was confirmed by X-ray analysis.

Abietanes↗
PubMed2005

Four new 6-nor5(6-->7)abeo-abietane type diterpenes and antitumoral cytotoxic diterpene constituents from the bark of Taiwania cryptomerioides.

Four new 6-nor-5(6-->7) abeo-abietane type diterpenes designated as taiwaniaquinone G, taiwaniaquinone H, taiwaniaquinol E and taiwaniaquinol F and eight known diterpenes, taiwaniaquinones A (5), D (6), E, F (8), and taiwaniaquinols A (9), B, C (11), D (12) were isolated from the bark of Taiwania cryptomerioides. Their structures were elucidated on the basis of spectroscopic studies. These twelve diterpenes were evaluated for in vitro antitumoral cytotoxic activity. The result demonstrated that compounds 5, 6, 8, 9, 11, and 12 bearing an aldehyde group possessed potent cytotoxic activity against KB epidermoid carcinoma cancer cell lines with IC50 values of 6.9, 7.2, 4.4, 8.3, 8.1, and 3.5 microM, respectively.

Abietanes↗
PubMed2005

Two diterpenes and three diterpene glucosides from Phlogacanthus curviflorus.

Two new diterpene lactones, phlogacantholides B (1) and C (2), and three new diterpene lactone glucosides, phlogacanthosides A (3), B (4), and C (5), together with lupeol, beta-sitosterol, betulin, beta-daucosterol, (+)-syringaresinol, and (+)-syringaresinol-4-O-beta-D-glucopyranoside, were isolated from the roots of Phlogacanthus curviflorus. Their structures were elucidated by chemical and spectroscopic evidence. The structure, including the relative configuration of phlogacantholide B (1), was confirmed by X-ray crystallographic analysis of its diacetate (6).

Crystallography, X-Ray↗
PubMed2004

Novel cassane and cleistanthane diterpenes from Myrospermum frutescens: absolute stereochemistry of the cassane diterpene series.

Four new diterpenes (1-4) were isolated from the leaves of Myrospermum frutescens as minor constituents. Chagresnol (1), 6beta,18-diacetoxycassan-13,15-diene (2), and chagreslactone (3) possess cassane skeletons, while chagresnone (4) exhibits a cleistanthane skeleton. Molecular structures and their relative stereochemistries were elucidated using NMR spectroscopy in combination with UV, IR, and MS spectral data. Although compound 2 was previously reported as a synthetic product, we report its first isolation as a natural product. Derivative products (10-13) were obtained to test their activities against Chagas's disease. In addition, the absolute stereochemistry of the previously isolated cassane diterpene 5 from M. frutescens is presented.

Animals↗
PubMed2005

A new isopimarane-type diterpene and a new natural atisane-type diterpene from Excoecaria agallocha.

From the woods of Excoecaria agallocha, a new isopimarane-type diterpene, 3alpha,11beta-dihydroxy-ent-isopimara-8(14),15-dien-2-one and a new natural atisane-type diterpene, 16beta-hydroxy-ent-atisan-3-one were isolated together with three known compounds, ribenone, ent-labda-8(17),13E-diene-3beta,15-diol, and ent-3beta-hydroxybeyer-15-ene-2,12-dione. Their structures were determined by spectral data and x-ray crystallography evidence.

Diterpenes↗
PubMed2006

Three abietane diterpenes and two diterpenes incorporated sesquiterpenes from the bark of Cryptomeria japonica.

Three new abietane diterpenes, sugikurojins D (1), E (2), and F (3), and two new abietanes which incorporate cadinane, sugikurojins G (4) and H (5) were isolated from the bark of Cryptomeria japonica. These structures were elucidated primarily by extensive NMR experiments. The structure of sugikurojin D (1) was deduced to be 6alpha-acetoxy-7beta,11-dihydroxy-12-methoxy-8,11,13-abietatriene. Sugikurojin E (2) was deduced to be 6alpha-acetoxy-7beta,12-dihydroxy-8,11,13-abietatriene. Sugikurojin F (3) was 7alpha-methoxy-8,13-abietadien-11,12-dione. Sugikurojins G (4) and H (5) had a unique skeleton incorporating an alpha-cadinol or a 1alpha-hydroxy-T-cadinol in ferruginol, respectively. Also obtained in this investigation were the known diterpenes (6-14). An antibacterial activity of ten among these against Staphylococcus aureus and Escherichia coli was inactive at the (MIC: 125 microg/ml) level. Meanwhile, in the cytotoxic activity against HL-60, compounds 4, 8, and 11 showed moderate (IC50: 4, 35.4; 8, 28.0; 11, 52.4 microM) though weak (IC50: 4, 100; 8, 80.8; 11, 100 microM) activity against HCT-15.

Abietanes↗
PubMed2002

Functional analysis of eubacterial diterpene cyclases responsible for biosynthesis of a diterpene antibiotic, terpentecin.

Eubacterial diterpene cyclase genes had previously been cloned from a diterpenoid antibiotic terpentecin producer (Dairi, T., Hamano, Y., Kuzuyama, T., Itoh, N., Furihata, K., and Seto, H. (2001) J. Bacteriol. 183, 6085-6094). Their products, open reading frame 11 (ORF11) and ORF12, were essential for the conversion of geranylgeranyl diphosphate (GGDP) into terpentetriene (TTE) that had the same basic skeleton as terpentecin. In this study, functional analyses of these two enzymes were performed by using purified recombinant enzymes. The ORF11 product converted GGDP into a cyclized intermediate, terpentedienol diphosphate (TDP), which was then transformed into TTE by the ORF12 product. Interestingly, the ORF12 product directly catalyzed the conversion of GGDP into three olefinic compounds. Moreover, the ORF12 product utilized farnesyl diphosphate as a substrate to give three olefinic compounds, which had the same structures as those formed from GGDP with the exception of the chain lengths. These results suggested that the ORF11 product with a DXDD motif converted GGDP into TDP by a protonation-initiated cyclization and that the ORF12 product with a DDXXD motif completed the transformation of TDP to the olefin, terpentetriene by an ionization-initiated reaction followed by deprotonation. The kinetics of the ORF12 product indicated that the affinity for TDP and GGDP were higher than that of farnesyl diphosphate and that the relative activity of the reaction converting TDP into TTE was highest among the reactions using TDP, GGDP, or farnesyl diphosphate as the substrate. These results suggested that an actual reaction catalyzed by the ORF12 was the conversion of TDP into TTE in vivo.

Anti-Bacterial Agents↗
PubMed2001

Biotransformation of diterpenes and diterpene derivatives by Beauveria bassiana ATCC 7159.

The biohydroxylation of stemodin and stemodinone by Beauveria bassiana ATCC 7159 gave exclusively 2alpha,13,18-trihydroxystemodane and 13,18-dihydroxystemodan-2-one respectively. Stemarin was converted to the novel 1beta,13,19-trihydroxystemarane and 13-hydroxystemarane-19-carboxylic acid. The synthesis and biotransformation of various derivatives of stemodin have also been studied.

Ascomycota↗
PubMed2006

Diterpene resin acid biosynthesis in loblolly pine (Pinus taeda): functional characterization of abietadiene/levopimaradiene synthase (PtTPS-LAS) cDNA and subcellular targeting of PtTPS-LAS and abietadienol/abietadienal oxidase (PtAO, CYP720B1).

Diterpene resin acids are prominent defense compounds against insect pests and pathogens in conifers. Biochemical and molecular analyses in grand fir (Abies grandis), Norway spruce (Picea abies), and loblolly pine (Pinus taeda) have identified two classes of genes and enzymes that generate much of the structural diversity of terpenoid defense compounds: The terpenoid synthases (TPS) and cytochrome P450 monooxgenases (P450). Using a single substrate, geranylgeranyl diphosphate, families of single-product and multi-product diterpene synthases generate an array of cyclic diterpene olefins. These diterpenes are converted to diterpene resin acids by activity of one or more P450 enzymes. A few conifer diterpene synthases have previously been cloned and characterized in grand fir and in Norway spruce. We have also previously shown that the loblolly pine P450 abietadienol/abietadienal oxidase (PtAO) catalyzes multiple oxidations of several diterpene alcohols and aldehydes. Conifer diterpene synthases are thought to function in plastids while P450s can also be localized to plastids or to the endoplasmic reticulum (ER). Here, we show that a loblolly pine cDNA (PtTPS-LAS) encodes a typical multi-product conifer diterpene synthase that forms levopimaradiene, abietadiene, palustradiene, and neoabietadiene similar to the grand fir abietadiene synthase and Norway spruce levopimaradiene/abietadiene synthase. Subcellular targeting of PtTPS-LAS and PtAO to plastids and ER, respectively, was shown with green fluorescent fusion protein expression in tobacco cells. These data suggest that enzymes for conifer diterpene resin acid biosynthesis are localized to at least two different subcellular compartments, plastids and ER, requiring efficient transport of intermediates and secretion of diterpene resin acids into the extracelluar space.

Alkyl and Aryl Transferases↗
PubMed1996

Biosynthesis of cyclic diterpene hydrocarbons in rice cell suspensions: conversion of 9,10-syn-labda-8(17),13-dienyl diphosphate to 9beta-pimara-7,15-diene and stemar-13-ene.

The biosynthesis of diterpene hydrocarbons with enzyme extracts from rice cell suspension cultures was investigated to verify proposed pathways and intermediates in the production of the momilactone and oryzalexin phytoalexins. Diterpene synthase activity in cells treated with chitin to elicit the phytoalexin response was compared with the activity in untreated cells using the acyclic substrates [1-3H](E,E,E)- and [1-3H] (E,Z,E)-geranylgeranyl diphosphates (GGPPs 4-OPP and 11-OPP) as well as the bicyclic substrates [15-3H]ent-copalyl and [15-3H] syn-copalyl diphosphates (CPPs, 5-OPP, and 6-OPP). ent-kaurene (7), ent-sanda, racopimaradiene (8), 9 beta H-pimara-7,15-diene (9), and stemar-13-ene (10) were identified as major products by comparisons with authentic standards. Marked increases in diterpene synthase activities were observed with enzyme from chitin-treated cells: (E,E,E)-GGPP (approximately 100 fold), ent-CPP (approximately 3 fold), and syn-CPP (approximately 60 fold). The very low conversions of (E,Z,E)-GGPP to hydrocarbon products excludes its role in the biosynthesis of 9,10-syn-diterpenes in rice cells. ent-Kaurene was the major diterpene formed from ent-CPP with enzyme from unelicited cells. In contrast the enzyme from chitin-treated cells converted ent-CPP to a mixture of ent-kaurene, ent-sandaracopimaradiene, and a third unidentified diterpene. With syn-CPP as substrate the induced syntheses afforded a mixture of 9 beta-pimaradiene, stemarene, and a third, unidentified syn-diterpene. Overall the results are consistent with the hypothesis that rice cells respond to treatment with chitin fragments by producing new diterpene synthases not present in the untreated cells. These induced cyclases initiate phytoalexin biosynthesis by diverting (E,E,E)-GGPP into new cyclization modes that produce ent-sandaracopimaradiene, stemarene, and 9 beta-pimaradiene, the presumed precursors to oryzalexins A-F, oryzalexin S, and momilactones A-C, respectively. The intermediate role of 9,10-syn-CPP in syn diterpene biosynthesis is verified.

Biotransformation↗