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Dali Meng - One of the best experts on this subject based on the ideXlab platform.
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New nor-Oleanane triterpenoids from the fruits of Stauntonia brachyanthera with potential anti-inflammation activity
Natural product research, 2019Co-Authors: Dan Liu, Dali MengAbstract:AbstractThe continuing studies on the fruits of Stauntonia brachyanthera led to the isolations of 6 normal and nor-Oleanane triterpenoids, including two new compounds, brachyantheoraside B10 (1) an...
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New nor-Oleanane triterpenoids from the fruits of Stauntonia brachyanthera with potential anti-inflammation activity
2019Co-Authors: Dan Liu, Dali MengAbstract:The continuing studies on the fruits of Stauntonia brachyanthera led to the isolations of 6 normal and nor-Oleanane triterpenoids, including two new compounds, brachyantheoraside B10 (1) and brachyantheraside C1 (2). Compounds 1–3 showed inhibitory activity on lipopolysaccharide (LPS)-induced nitric oxide production in RAW 264.7 macrophages with the IC50 values of 27.04, 26.22, and 21.41 μM, respectively, which were all stronger than that of indomethacin. The study not only revealed a new type of nor-Oleanane triterpenoids, but also confirmed the anti-inflammation abilities of three type nor-Oleanane triterpenoids as the inhibitors of NO production.
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Anti-gout nor-Oleanane triterpenoids from the leaves of Stauntonia brachyanthera
Bioorganic & medicinal chemistry letters, 2016Co-Authors: Xuan-li Liu, Dali MengAbstract:With the aim of finding more potential anti-gout compounds from natural resources, a phytochemical study on the leaves of Stauntonia brachyanthera was carried out, which led to the isolation of 11 nor-Oleanane triterpenoids, including 4 new ones. Their structures were determined by the comprehensive 1D, 2D NMR, HRMS, and HPLC analysis after acid hydrolysis. Brachyantheraoside B4 (3) and 3-O-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyl-30-norolean-12,20(29)-dien-28-oic acid (8) exhibited significant inhibitory activities on xanthine oxidase with IC50 values of 0.20 and 18.5μM, respectively. Brachyantheraoside C2 (2) also showed moderate effects on XO. A primary structure-activity relationship was also summarized, which revealed the anti-gout abilities of three nor-Oleanane triterpenoids and their potential possibilities as the candidate compounds for the treatment of gout. The discovery of nor-Oleanane triterpenoids also widens people's idea for the study of anti-gout agents and promotes the comprehensive development of S. brachyanthera.
Hans Peter Nytoft - One of the best experts on this subject based on the ideXlab platform.
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Unusual hexacyclic Oleananes in Late Cretaceous/Tertiary terrigenous oils: NMR characterisation of the major hexacyclic Oleanane in Niger Delta oil
Organic Geochemistry, 2016Co-Authors: Hans Peter Nytoft, Geir Kildahl-andersen, Frode RiseAbstract:Abstract Four hexacyclic Oleananes having characteristic mass spectra with an intense fragment at m / z 325 were found in Late Cretaceous/Tertiary terrigenous oils and immature source rocks containing 18α-Oleanane and other saturated pentacyclic compounds of higher plant origin. They are sometimes as abundant as 18α-Oleanane itself. They were not found in oils without Oleanane. The major hexacyclic Oleanane, comprising 50–80% of the hexacyclic Oleananes, was isolated using high performance liquid chromatography (HPLC) and characterized using nuclear magnetic resonance spectroscopy (NMR) as 18α-Oleanane with the Me group at C-10 shifted to C-9 and with the Me at C-14 creating a new methylene bridge to C-10. Hexacyclic Oleananes were not visible in m / z 191 chromatograms. They are most effectively detected by way of GC-MS-MS using the m / z 410 → 325 transition. Since few other compounds produce any m / z 410 → 325 signal, they may sometimes be easier to detect than regular and rearranged Oleananes in samples with a low concentration of angiosperm markers. Precursor natural products have not been identified among plant triterpenoids, but might be related to (poly)functionalized oleanoids. Oleanoids hydroxylated at C-27 are obvious precursors. Oxic/clay-rich depositional environments seem to favour the formation of hexacyclic Oleananes. A series of 2-alkylated Oleananes had previously been characterized using NMR. Their hexacyclic counterparts were tentatively assigned in this study.
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Compound “J” in Late Cretaceous/Tertiary terrigenous oils revisited: Structure elucidation of a rearranged Oleanane coeluting on GC with 18β(H)-Oleanane
Organic Geochemistry, 2014Co-Authors: Hans Peter Nytoft, Geir Kildahl-andersen, Tatjana Šolević Knudsen, Ksenija Stojanović, Frode RiseAbstract:Abstract A C30 pentacyclic triterpane eluting slightly after 18α(H)-Oleanane in the m/z 191 mass chromatograms of Late Cretaceous/Tertiary terrigenous oils (peak “J” in the early literature) has been isolated from a Niger Delta oil and identified using NMR spectroscopy as 3β-methyl-24-nor-18α(H)-Oleanane. The previous assignment as 18β(H)-Oleanane is therefore partly erroneous. 3β-Methyl-24-nor-18α(H)-Oleanane affords a larger m/z 412 → 356 response than the Oleananes and the relative contribution of 3β-methyl-24-nor-18α(H)-Oleanane to the 412 → 191 “Oleanane peak” can be roughly estimated from comparison of the 412 → 356/412 → 191 ratio from the Oleanane peak with that of the pure compounds. 3β-Methyl-24-nor-18α(H)-Oleanane can be as abundant as 18α(H)-Oleanane in oils having a high concentration of early eluting rearranged Oleananes. 3β-Methyl-24-nor-19α(H)-taraxastane was also tentatively assigned in the oils on the basis of its mass spectrum as well as its gas chromatography and high performance liquid chromatography retention times. 3β-Methyl-24-nor-gammacerane was tentatively assigned in a similar way in an oil containing gammacerane. All 3β-methyl-24-nor-triterpanes could be formed via dehydration, rearrangement and hydrogenation of triterpenoids having an OH group at C-3.
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Rearranged Oleananes: Structural identification and distribution in a worldwide set of Late Cretaceous/Tertiary oils
Organic Geochemistry, 2010Co-Authors: Hans Peter Nytoft, Geir Kildahl-andersen, Olukayode James SamuelAbstract:Abstract The three most abundant rearranged oleanoid triterpanes eluting early in gas chromatography (GC) have been isolated from a Niger Delta oil and characterized using nuclear magnetic resonance (NMR) spectroscopy. The NMR data confirmed the identification of two of them, observed previously in the literature, as 1(10 → 5)abeo-3β-methyl-24β-nor-18α(H)-Oleanane and 5(4 → 3)abeo-3α(H), 5β(Η), 18α(Η)-Oleanane on the basis of X-ray crystallography and comparison with a synthetic standard. The third compound was a novel rearranged Oleanane, 3α,5β-dimethyl-23α,25-dinor-10β(H),18α(H)-Oleanane, with one of the methyl groups at C-4 in the Oleanane structure shifted to C-3 and another shifted from C-10 to C-5. The distribution of these three rearranged Oleananes and other, yet unidentified, rearranged oleanoid C 30 triterpanes in 25 Late Cretaceous- or Tertiary-sourced oils from Angola, Canada, Greece, India, Indonesia, Iran, New Zealand, Nigeria and Vietnam was examined by way of reverse phase high pressure liquid chromatography (HPLC), GC–mass spectrometry (GC–MS) and GC–MS–MS. Mass spectra of rearranged Oleananes and compounds tentatively assigned as rearranged taraxastanes are presented. Rearranged Oleananes and other rearranged triterpanes are probably formed by dehydration and rearrangement of higher plant triterpenoids functionalized at C-3. The distribution of rearranged Oleananes and their relative concentration seems to be dependent on the extent of clay catalysis during diagenesis. A diagenetic pathway for formation of the rearranged Oleananes is proposed. All 25 oils have almost identical rearranged Oleanane/Oleanane and diasterane/regular sterane ratio values. Two unidentified early eluting (GC) rearranged Oleananes are only abundant in oils with a high proportion of diasteranes. Bicadinanes were found in 20 of the 25 oils.
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Oleanane or lupane reappraisal of the presence of Oleanane in cretaceous tertiary oils and sediments
Organic Geochemistry, 2002Co-Authors: Hans Peter Nytoft, Flemming G. Christiansen, Jorgen A Bojesenkoefoed, Martin G. FowlerAbstract:Nonpolar GC-columns are normally used for GC–MS analysis of saturate fractions from crude oils. Under these conditions lupane coelutes with Oleananes and some minor C30 compounds of non-terrigenous origin having lupane-like mass spectra. Because any peak eluting fractionally earlier than 17α,21β(H)-hopane in the m/z 191 mass chromatogram is routinely assigned to Oleanane, the presence of lupane may sometimes have been overlooked. Lupane and Oleananes are easily separated using reverse phase HPLC. Triterpane concentrates from 10 crude oils known to contain Oleananes were HPLC-separated. Lupane was unambiguously identified in six of the oils by full-scan GC–MS analysis of fractions having the HPLC-retention time of authentic lupane. GC-separation of lupane and Oleananes is possible using polar GC-columns having a polyethylene glycol stationary phase [Organic Geochemistry, 23 (1995) 21], allowing estimation of the lupane/(lupane+Oleanane) ratio. High ratios were measured in the Marraat oil, West Greenland (0.8) and the Amauligak oil from the Beaufort–Mackenzie Delta (0.26). The results suggest that lupane may be more frequently occurring than previously thought, and that this compound is preferably associated with high latitude samples. High concentrations of 28-nor- and 24,28-bisnortriterpanes (Oleananes, lupanes and taraxastanes) were detected in the Marraat oil.
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Oleanane or lupane? Reappraisal of the presence of Oleanane in Cretaceous–Tertiary oils and sediments
Organic Geochemistry, 2002Co-Authors: Hans Peter Nytoft, Jørgen A. Bojesen-koefoed, Flemming G. Christiansen, Martin G. FowlerAbstract:Nonpolar GC-columns are normally used for GC–MS analysis of saturate fractions from crude oils. Under these conditions lupane coelutes with Oleananes and some minor C30 compounds of non-terrigenous origin having lupane-like mass spectra. Because any peak eluting fractionally earlier than 17α,21β(H)-hopane in the m/z 191 mass chromatogram is routinely assigned to Oleanane, the presence of lupane may sometimes have been overlooked. Lupane and Oleananes are easily separated using reverse phase HPLC. Triterpane concentrates from 10 crude oils known to contain Oleananes were HPLC-separated. Lupane was unambiguously identified in six of the oils by full-scan GC–MS analysis of fractions having the HPLC-retention time of authentic lupane. GC-separation of lupane and Oleananes is possible using polar GC-columns having a polyethylene glycol stationary phase [Organic Geochemistry, 23 (1995) 21], allowing estimation of the lupane/(lupane+Oleanane) ratio. High ratios were measured in the Marraat oil, West Greenland (0.8) and the Amauligak oil from the Beaufort–Mackenzie Delta (0.26). The results suggest that lupane may be more frequently occurring than previously thought, and that this compound is preferably associated with high latitude samples. High concentrations of 28-nor- and 24,28-bisnortriterpanes (Oleananes, lupanes and taraxastanes) were detected in the Marraat oil.
Li-wen Tian - One of the best experts on this subject based on the ideXlab platform.
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A new polyhydroxylated Oleanane triterpenoid from the roots of Rhodomyrtus tomentosa.
Natural product research, 2018Co-Authors: Xue-li Tong, Hai-tao Wang, Li-wen TianAbstract:A new Oleanane triterpenoid, 2α,3β,6β,23,29-pentahydroxyolean-12-en-28- oic acid (1), was isolated from the roots of Rhodomyrtus tomentosa, together with four known Oleanane triterpenoids (2–5) and...
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A new polyhydroxylated Oleanane triterpenoid from the roots of Rhodomyrtus tomentosa
2018Co-Authors: Xue-li Tong, Hai-tao Wang, Li-wen TianAbstract:A new Oleanane triterpenoid, 2α,3β,6β,23,29-pentahydroxyolean-12-en-28- oic acid (1), was isolated from the roots of Rhodomyrtus tomentosa, together with four known Oleanane triterpenoids (2–5) and two known ursane triterpenoids (6–7). The structure of compound 1 was determined by extensive NMR and HR-ESI-MS data analysis. Compounds 4–5 showed cytotoxicity against PC12 cell lines at a concentration of 50 μM, and compound 1 exhibited moderate neuroprotective activity against corticosterone induced PC12 cell death at the same concentration.
Dan Liu - One of the best experts on this subject based on the ideXlab platform.
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New nor-Oleanane triterpenoids from the fruits of Stauntonia brachyanthera with potential anti-inflammation activity
Natural product research, 2019Co-Authors: Dan Liu, Dali MengAbstract:AbstractThe continuing studies on the fruits of Stauntonia brachyanthera led to the isolations of 6 normal and nor-Oleanane triterpenoids, including two new compounds, brachyantheoraside B10 (1) an...
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New nor-Oleanane triterpenoids from the fruits of Stauntonia brachyanthera with potential anti-inflammation activity
2019Co-Authors: Dan Liu, Dali MengAbstract:The continuing studies on the fruits of Stauntonia brachyanthera led to the isolations of 6 normal and nor-Oleanane triterpenoids, including two new compounds, brachyantheoraside B10 (1) and brachyantheraside C1 (2). Compounds 1–3 showed inhibitory activity on lipopolysaccharide (LPS)-induced nitric oxide production in RAW 264.7 macrophages with the IC50 values of 27.04, 26.22, and 21.41 μM, respectively, which were all stronger than that of indomethacin. The study not only revealed a new type of nor-Oleanane triterpenoids, but also confirmed the anti-inflammation abilities of three type nor-Oleanane triterpenoids as the inhibitors of NO production.
Xue-li Tong - One of the best experts on this subject based on the ideXlab platform.
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A new polyhydroxylated Oleanane triterpenoid from the roots of Rhodomyrtus tomentosa.
Natural product research, 2018Co-Authors: Xue-li Tong, Hai-tao Wang, Li-wen TianAbstract:A new Oleanane triterpenoid, 2α,3β,6β,23,29-pentahydroxyolean-12-en-28- oic acid (1), was isolated from the roots of Rhodomyrtus tomentosa, together with four known Oleanane triterpenoids (2–5) and...
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A new polyhydroxylated Oleanane triterpenoid from the roots of Rhodomyrtus tomentosa
2018Co-Authors: Xue-li Tong, Hai-tao Wang, Li-wen TianAbstract:A new Oleanane triterpenoid, 2α,3β,6β,23,29-pentahydroxyolean-12-en-28- oic acid (1), was isolated from the roots of Rhodomyrtus tomentosa, together with four known Oleanane triterpenoids (2–5) and two known ursane triterpenoids (6–7). The structure of compound 1 was determined by extensive NMR and HR-ESI-MS data analysis. Compounds 4–5 showed cytotoxicity against PC12 cell lines at a concentration of 50 μM, and compound 1 exhibited moderate neuroprotective activity against corticosterone induced PC12 cell death at the same concentration.
