Cmr Spectroscopy of Labdanic Diterpenes and Related Substances

Bastard, Josette; Duc, Do Khac Manh Duc Do Khac Manh; Fétizon, M.; Francis, Malcolm J.; Grant, P. K.; Weavers, Rex T.; Kaneko, Chikara; Baddeley, G.; Bernassau, Jean‐Marie; Burfitt, Ivor R.; Wovkulich, Peter M.; Wenkert, Ernest

doi:10.1021/np50034a004

Cited by 61 publications

(43 citation statements)

References 15 publications

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“…The HMBC spectrum indicated that these oxirane protons have a 1 H-13 C interaction with the quaternary C8 position, and, in the COSY spectra, a 4 J 1 H-1 H coupling was observed between the downfield oxirane proton (δ H 2.82 ppm) and one of the C7 protons (δ H 1.92 ppm). Similar chemical shifts were observed in several other labdanes [31][32][33][34][35][36] with a spiro-epoxy group at C8. Another downfield resonance was observed at δ C 83.8 ppm, which is consistent with an allylic alcohol, with the position established as C12 using the HMBC spectrum.…”

Section: Structural Characterisation Of Diterpenes 4-8supporting

confidence: 84%

New Labdanes with Antimicrobial and Acaricidal Activity: Terpenes of Callitris and Widdringtonia (Cupressaceae)

et al. 2020

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In spite of the evidence for antimicrobial and acaricidal effects in ethnobotanical reports of Callitris and Widdringtonia, the diterpene acids from Widdringtonia have never been described and no comparison to the Australian clade sister genus Callitris has been made. The critically endangered South African Clanwilliam cedar, Widdringtonia wallichii (syn. W. cedarbergensis), of the Cederberg Mountains was once prized for its enduring fragrant timbers and an essential oil that gives an aroma comparable to better known Mediterranean cedars, predominantly comprised by widdrol, cedrol, and thujopsene. In South Africa, two other ‘cedars’ are known, which are called W. nodiflora and W. schwarzii, but, until now, their chemical similarity to W. wallichii has not been investigated. Much like Widdringtonia, Callitris was once prized for its termite resistant timbers and an ‘earthy’ essential oil, but predominantly guaiol. The current study demonstrates that the essential oils were similar across all three species of Widdringtonia and two known non-volatile diterpene acids were identified in leaves: the pimaradiene sandaracopimaric acid (1) and the labdane Z-communic acid (2) with a lower yield of the E-isomer (3). Additionally, in the leaves of the three species, the structures of five new antimicrobial labdanes were assigned: 12-hydroxy-8R,17-epoxy-isocommunic acid (4), 8S-formyl-isocommunic acid (5), 8R,17-epoxy-isocommunic acid (6), 8R-17R-epoxy-E-communic acid (7), and 8R-17-epoxy-E-communic acid (8). Australian Callitris columellaris (syn. C. glaucophylla) also produced 1 and its isomer isopimaric acid, pisiferal (9), and pisiferic acid (10) from its leaves. Callitris endlicheri (Parl.) F.M.Bailey yielded isoozic acid (11) as the only major diterpene. Diterpenes 4–6, pisiferic acid (10), spathulenol, and guaiol (12) demonstrated antimicrobial and acaricidal activity.

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Section: Structural Characterisation Of Diterpenes 4-8supporting

confidence: 84%

New Labdanes with Antimicrobial and Acaricidal Activity: Terpenes of Callitris and Widdringtonia (Cupressaceae)

et al. 2020

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“…3,25 These isomers showed essentially identical NMR spectral properties for ring skeletal proton and carbon signals and only differed in signals attributable to the side chain. Comparison with NMR spectral properties of other E and Z isomers of labdane diterpenes 15,16 and from the literature 13,14,27 confirmed the structure of 4E. Isomer 4Z was unknown.…”

Section: Resultssupporting

confidence: 57%

In Vitro Biotransformations of Isocupressic Acid by Cow Rumen Preparations: Formation of Agathic and Dihydroagathic Acids

Lin

Short²,

Ford

et al. 1998

J. Nat. Prod.

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Isocupressic acid [15-hydroxylabda-8(17), 13E-dien-19-oic acid] (1) was incubated under anaerobic conditions for 48 h in an in vitro ruminal fluid mixture and was transformed into two metabolites. The two metabolites were identified by GC/MS as agathic acid [labda-8(17),13(E)-diene-15,19-dioic acid] (4E) and dihydroagathic acid [labda-8(17)-ene-15,19-dioic acid] (6). Metabolite identities were confirmed by chemical conversions of isocupressic acid (1) and imbricataloic acid (5) into 4E and 6, respectively. Structures of synthetic metabolites were confirmed by 1 H and 13 C NMR, specific rotation, GC/MS, and high-resolution mass spectrometry. Plasma obtained from cows that were fed Ponderosa pine needles contained (13R,S)-dihydroagathic acid (6) but not isocupressic acid (1) or 4E. The results suggest that isocupressic acid (1) is metabolically oxidized to agathic acid (4E), subsequently reduced to (13R,S)-dihydroagathic acid (6) in the rumen, and then absorbed into the bloodstream of cattle.Premature parturition in cattle due to the ingestion of Ponderosa pine [Pinus ponderosa Dougl. ex Laws (Pinaceae)] needles is a major economic problem in the Western United States and Canada. 1 Previous investigations have attempted to isolate and characterize the compounds in P. ponderosa responsible for pine needle abortion. A new class of vasoactive lipids 2 and isocupressic acid 3 [15-hydroxylabda-8(17),13(E)-dien-19-oic acid] (1) were identified as possible causative agents in pine needle abortion in pregnant cows. However, the effects of pine needle ingestion on domestic ruminants such as cattle, Bison, sheep, and goats are variable with regard to the parturition response and/or the presence of vasoconstrictive principles present in plasma samples. [4][5][6] The species differences observed in the pine needle abortion phenomenon may result from variability in the differences in digestive systems among species, from differences of possible metabolic transformations of ingested precursor abortifacient compounds, or from a combination of these factors.Ruminants, including cattle, possess a four-compartment stomach. The largest compartment, the rumen, contains a mixed and variable population of symbiotic microorganisms effective in fermenting fibrous feedstuffs into nutrients usable by the host animal. The environment in the rumen is generally anaerobic, neutral to slightly acidic (between pH 5.5-7.0), and at a temperature between 38 and 41°C. During digestion, the rumen microflora cooperatively catalyze enzymatic transformations of nutrients, fiber, and other ingested substances. Digested materials ultimately pass into the bloodstream of the ruminant animal where they are broadly distributed, bound, further metabolized, and ultimately excreted.The mechanism whereby pine-needle ingestion induces abortion in cattle has been shown to involve a reduction in blood flow to the gravid uterus, resulting in a marked and progressive decrease in nutrients and oxygen available to the fetal calf. 4,7 This is consistent with the observa...

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“…The 1 H and 13 C NMR spectra (CDCl3) and correlations observed from the NOESY spectrum of potamogetonyde (3) and potamogetonol (4). This material is available free of charge via the Internet at http://pubs.acs.org.…”

Section: Acknowledgmentmentioning

confidence: 99%

Potent Antiviral Potamogetonyde and Potamogetonol, New Furanoid Labdane Diterpenes from Potamogeton malaianus

et al. 2001

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New furanoid labdane diterpenes, potamogetonyde (3) and potamogetonol (4), together with two known compounds, potamogetonin (1) and 15,16-epoxy-12-oxo-8(17),13(16),14-labdatrien-20,19-olide (2), were isolated from the CH(2)Cl(2) extract of Potamogeton malaianus. The chemical structures of 1-4 were elucidated by the analyses of their spectral data, mainly by 1D and 2D NMR techniques. Potamogetonyde (3) and potamogetonol (4) exhibited potent antiviral (HSV-1) activity with respective IC(50) values of 8 and 3 microg/mL. Compounds 1-4 possessed cytotoxicity toward insect cells (fall armyworm and mosquito larvae, IC(50) of 11-72 microg/mL). Furanoid diterpenes 3 and 4 also exhibited cytotoxicity against the Vero cell line with respective IC(50)'s of 31 and 28 microg/mL, while 1 and 2 were inactive at 50 microg/mL. Compounds 1-4 were inactive (at 20 microg/mL) against KB and BC cell lines and showed only weak antimycobacterial activity against Mycobacterium tuberculosis H37Ra with minimum inhibitory concentrations of 50-100 microg/mL.

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Cmr Spectroscopy of Labdanic Diterpenes and Related Substances

Cited by 61 publications

References 15 publications

New Labdanes with Antimicrobial and Acaricidal Activity: Terpenes of Callitris and Widdringtonia (Cupressaceae)

New Labdanes with Antimicrobial and Acaricidal Activity: Terpenes of Callitris and Widdringtonia (Cupressaceae)

In Vitro Biotransformations of Isocupressic Acid by Cow Rumen Preparations: Formation of Agathic and Dihydroagathic Acids

Potent Antiviral Potamogetonyde and Potamogetonol, New Furanoid Labdane Diterpenes from Potamogeton malaianus

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