查看更多>>摘要：Ten nardosinane-related terpenoids, including five unreported nardosinane-type sesquiterpenoids, parathyrsoidins H-J and linardosinenes D-E, two unusual condensed nardosinanes, named nardosinoids A and B, together with three known related compounds, were isolated from the Xisha soft coral Lemnalia sp. Their structures were elucidated by extensive spectroscopic analysis and comparison of experimental and calculated electronic circular dichroism data. Nardosinoids A and B are the first condensates of two nardosinanes. All these compounds were evaluated for antimicrobial activity in vitro. Nardosinane-type sesquiterpenoids parathyrsoidin I and linardosinene E showed inhibitory effects against influenza A virus H1N1 (IC50 7.1 and 1.1 mu M, respectively). In addition, nardosinoids A and B exhibited antibacterial activity against Bacillus subtilis (MIC 4-8 mu g/mL).
查看更多>>摘要：Ten siderophore-related compounds were isolated by MS/MS-based molecular networking from a mesophotic sponge-associated Streptomyces diastaticus NBU2966. Among them, there were three kinds of siderophores including three undescribed phenol/thiazoline-type compounds, thiazostatin C, methyl thiazostatin B, and pulicatin J, one undescribed phenol/oxazoline-type compound, spoxazomicin E, and one undescribed phenol/ oxazoline/thiazoline-type compound, streptochelin A, as well as five known compounds. Pulicatin J and spoxazomicin E were both isolated as a pair of inseparable epimers. The planar structures of all these compounds were determined based on the detailed NMR and HRESIMS spectroscopic analysis, and the absolute configurations of them were assigned by ECD and NMR quantum chemical calculations. Additionally, in vitro antibacterial activities, inhibition of MRSA biofilm formation, and neuroprotective activity for these compounds were tested.
查看更多>>摘要：Sixteen cassane diterpenoids (CAs), including four undescribed lactam-type, four unreported lactone-type, along with eight known ones, were isolated from the aerial parts of Caesalpinia pulcherrima (L.) Sw. Their structures were characterized by comprehensive spectroscopic analyses (including NMR and HRESIMS). The absolute configuration of pulcherritam A was finally established by single-crystal X-ray diffraction with Cu K alpha radiation. Notably, pulcherritam s A-D were elucidated as a group of rare CAs bearing an alpha, beta-unsaturated gamma-lactam ring rather than a typical lactone moiety. Almost all compounds were examined for their antibacterial. The results reveal that pulcherritam H exhibited significant antibacterial activities against Bacillus cereus, Staphylococcus aureus, as well as Pseudomonas syringae pv. actinidae (Psa) with the MIC from 6.25 to 12.5 mu M, while pulcherritams A and C displayed potent antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA). Then, all isolates were evaluated for their anti-glioblastoma activities. Pulcherritam A and Pulcherrimin G illustrated moderate inhibitory activity against glioblastoma multiforme (GBM) U87MG cell, and the other compounds did not show obvious inhibitory activity against GBM U87MG cell. Furthermore, the preliminary structure-activity relationship and their biosynthetic pathway were also discussed.
查看更多>>摘要：The mature fruit of Psoralea corylifolia L. is a common traditional Chinese medicine used to tonify the kidney and yang, and as well as to treat osteoporosis. Systematic phytochemical investigations have established the most comprehensive constituent library to date, covering over 180 compounds. In this study, 109 chemical constituents containing 37 undescribed compounds were reported and incorrect structures of four known coumarins were corrected. The structures of these undescribed compounds were elucidated using spectroscopic methods, single-crystal X-ray diffraction, Rh-2(OCOCF3)(4) and Mo-2(OAc)(4)-induced circular dichroism spectra. To identify potentially active compounds and investigate their structure-activity relationship (SAR), 89 constituents in the library were evaluated for their osteogenic differentiation and mineralisation activities in MC3T3-E1 cells. We found that coumarins, isoflavones, flavonones, and meroterpenoids were the material basis for Psoralea corylifolia-based treatment of osteoporosis, with some compounds exhibiting excellent activities. These compounds function via the estrogen receptor (ER) pathway and were natural phytoestrogen. Further SAR analysis showed that compounds with an intact isopentenyl replacement possessed superior activities, which was explained by their improved affinity with the ER.
查看更多>>摘要：To investigate the biosynthetic pathways and regulatory mechanisms of lignans in plants, the actual distributions of lignans and lignan glucosides in flash-frozen stems of Ginkgo biloba L. (Ginkgoaceae) were studied using cryo time-of-flight secondary ion mass spectrometry coupled with scanning electron microscopy (cryo-TOF-SIMS/ SEM). Four lignans and four lignan glucosides were successfully characterized. Quantitative HPLC measurements were conducted on serial tangential sections of freeze-fixed ginkgo stem to determine the amount and approximate distribution of lignan and lignan glucosides. (-)-Olivil 4,4 '-di-O-beta-D-glucopyranoside (olivil DG) was the most abundant lignan glucoside in ginkgo and was distributed mainly in the phloem, ray parenchyma cells, and pith. The comparative accumulation of olivil DG revealed its possible transport pathways and storage sites in ginkgo. Although not all relevant enzymes have been identified, understanding the distributions of lignan and lignan glucosides in ginkgo stems provides significant insight into their biological functions.
查看更多>>摘要：Eremophila (Scrophulariaceae) is a genus of Australian desert plants, which have been used by Australian Aboriginal people for various medicinal purposes. Crude extracts of the leaf resin of Eremophila glabra (R.Br.) Ostenf. showed alpha-glucosidase and protein tyrosine phosphatase 1B (PTP1B) inhibitory activity with IC50 values of 19.3 +/- 1.2 mu g/mL and 11.8 +/- 2.1 mu g/mL, respectively. Dual alpha-glucosidase/PTP1B high-resolution inhibition profiling combined with HPLC-PDA-HRMS and NMR were used to isolate and identify the compounds providing these activities. This resulted in isolation of seven undescribed serrulatane diterpenoids, eremoglabrane A-G, together with nine previously identified serrulatane diterpenoids and flavonoids. Three of the serrulatane diterpenoids showed PTP1B inhibitory activities with IC50 values from 63.8 +/- 5.8 mu M to 104.5 +/- 25.9 mu M.
查看更多>>摘要：Eight undescribed cassane diterpenes, pterolobirins C-J, together with two known analogs, were isolated from the roots of Pterolobium macropterum. Their structures were characterized by extensive spectroscopic techniques including NMR, MS, ECD and X-ray crystallographic spectroscopy. The absolute configuration of pterolobirin J was confirmed by single-crystal X-ray diffraction data. The compounds were screened for their anti-inflammatory activity on the lipopolysaccharide (LPS) induced nitric oxide (NO) production in J774. A1 macrophage cells. Pterolobirin E and sucutinirane C displayed good NO inhibition with IC50 values of 24.44 +/- 1.34 and 19.16 +/- 1.22 mu M, respectively.
查看更多>>摘要：Five undescribed triterpenoids, two unusual omphalane-type sesquiterpenoids together with twenty-five known compounds were isolated from the leaves and stems of Rhododendron minutiflorum Hu. The absolute configurations of 1-3 and 6 were established by single-crystal X-ray diffraction analysis and electronic circular dichroism (ECD). Compounds 6-7 feature the rare omphalane-type sesquiterpene skeleton and are verified by single-crystal X-ray diffraction analysis for the first time. In the biological activity assay, most of the triterpenoids have different degrees of inhibitory effects on alpha-glucosidase, with IC50 values ranging from 6.97 to 229.3 mu M (the positive control drug acarbose has an IC50 value of 3.07 x 10 3 mu M). Structure and activity relationship (SAR) study reveals that the oxidation degrees of C-3, C-8, or C-11 to C-13 of the ursane-type triterpenoid influence the inhibitory activity dramatically.
查看更多>>摘要：(+/-)-trichodermatrione A, a pair of cyclobutane-containing enantiomers with an undescribed tricyclic 6/4/6 skeleton, was isolated from Trichoderma sp. EFT2, an endophytic fungus from Euonymus fortunei (Turcz.) Hand.-Mazz (Celastraceae). The racemates were separated by chiral HPLC with the structures elucidated by a combination of MS, NMR, ECD calculation and X-ray crystallography analyses. (+/-)-trichodermatrione A and enantiomers were found to be antibacterial against phytopathogenic bacteria Xanthomonas oryzae pv. oryzae (Xoo) and X. oryzae pv. oryzicola (Xoc).
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