查看更多>>摘要：The first investigation of Phyllanthus mirabilis Mull.Arg. led to the isolation of six undescribed compounds including two tyramine derivatives: phyllatyramines A and B; three butenolide analogues, phyllantenolide, phyllantenocoside-O-gallate and epi-phyllantenocoside-O-gallate; and a flavanonol gallate, (-)-taxifolin-3-Ogallate; as well as two first isolated natural products, phyllatyramine C and phyllantenocoside; together with twenty-three known compounds. Their structures were elucidated by spectroscopic means. ECD spectra of all isolated butenolides were compared and assigned the configurations. Phyllatyramine A displayed weak cytotoxicity against the KB cell line, while phyllatyramines B and C showed weak cytotoxicity against KB and HeLa cell lines. In addition, phyllatyramine B and (-)-taxifolin-3-O-gallate showed more potent alpha-glucosidase inhibitory activity than the standard acarbose 3.4 and 5.8 fold, respectively.
Sosa-Rueda, JavierDominguez-Melendez, VanihaminOrtiz-Celiseo, AraceliLopez-Fentanes, Fernando C....
7页
查看更多>>摘要：Four cyclic octapeptides, squamins C-F, were isolated from the seeds of Annona globiflora Schltdl. These compounds share part of their amino acid sequence, -Pro-Met(O)-Tyr-Gly-Thr-, with previously reported squamins A and B. Their structures were determined using NMR spectroscopic techniques together with quantum mechanical calculations (QM-NMR), ESI-HRMS data and a modified version of Marfey's chromatographic method. All compounds showed cytotoxic activity against DU-145 (human prostate cancer) and HeLa (human cervical carcinoma) cell lines. Clearly, A. globiflora is an important source of bioactive molecules, which could promote the sustainable exploitation of this undervalued specie.
查看更多>>摘要：Seven undescribed dammarane-type saponins, gypenosides LXXXI-LXXXVII, together with four known compounds, were isolated from the whole herb of Gynostemma pentaphyllum. The chemical structures of these undescribed compounds were elucidated on the basis of physical and spectroscopic analysis and comparison with literature data. All the isolates were evaluated for their proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitory activities in HepG2 cells. Among them, gypenosides LXXXII-LXXXVII, gynosaponin II, IV and VI suppressed the expression of PCSK9 in LPDS-induced HepG2 cells at 20 mu M; gypenosides LXXXII, LXXXV and LXXXVII showed inhibitory activities against PCSK9 at 10 mu M; notably, gypenoside LXXXII still exhibited inhibitory activity against PCSK9 at 5 mu M.
查看更多>>摘要：Nauclea pobeguinii is traditionally used for treatment of malaria. Previous studies on the plant extract and strictosamide, the putative active constituent, showed a profound in vivo activity of the extract but no in vitro activity of strictosamide. This might indicate that one or more compounds present in the extract, most likely alkaloids, act as prodrugs undergoing biotransformation after oral administration resulting in the active compounds. The phytochemical composition of a N. pobeguinii extract was characterized using UHPLC-UV-HRMS (Ultrahigh-Performance Liquid Chromatography-Ultraviolet-High Resolution Mass Spectrometry) data. An in vitro gastrointestinal model was used to simulate biotransformation of the extract allowing monitoring of the relative abundances of individual constituents over time on one hand, while antiplasmodial activity and cytotoxicity of the biotransformed extract could be evaluated on the other hand. A diversity of compounds was (tentatively) identified in the extract, mainly saponins and alkaloids, including 32 compounds that have not been reported before in N. pobeguinii. The automated data analysis workflow used for unbiased screening for metabolites showed that glycosylated compounds decreased in intensity over time. Alkaloids containing no sugar moieties, including angustine-type alkaloids, showed no gastrointestinal biotransformation. In vitro gastrointestinal biotransformation of strictosamide did not result in a major metabolite. Moreover, multivariate data analysis using Orthogonal Partial Least Square-Discriminant Analysis (OPLS-DA) showed no in vitro activity of strictosamide or its metabolites suggesting that other compounds or metabolites present in the extract are responsible for the antiplasmodial effect of the N. pobeguinii extract. The OPLS-DA proposes alkaloids with a beta-carboline moiety as active principles, suggesting that antiplasmodial activity of N. pobeguinii derives from an additive or synergistic effect of multiple minor alkaloids and their metabolites present in the bark extract of N. pobeguinii.
查看更多>>摘要：Phaeosphspirone, an undescribed polyketide with a unique 6/5/5/6-fused tetracyclic system, and two known analogues, herbarin and O-methylherbarin, were purified from the endophytic fungus Phaeosphaeriaceae sp. isolated from the desert plant Bassia dasyphylla. The connectivity and relative configuration of phaeosphspirone was elucidated by comprehensive HR-ESI-MS and NMR analysis together with a computer-assisted structure elucidation (CASE) method. A pair of enantiomers existing in phaeosphspirone were separated by HPLC chromatography after reacting with chiral reagents, from which the absolute configuration of phaeosphspirone was simultaneously determined based on Mosher's rule. This tandem strategy provides a useful approach for the separation and stereochemical determination of enantiomers possessing secondary hydroxyl groups. The structural feature of phaeosphspirone, herbarin and O-methylherbarin together with gene cluster analysis suggested their polyketide biosynthetic origin. Herbarin and O-methylherbarin exhibited moderate cytotoxicity against three cancer cell lines.
查看更多>>摘要：(+)/(-)-Diobolignans A-F, six pairs of enantiomeric obovatol dimeric neolignans, were isolated from the bark of Magnolia officinalis var. biloba. (+)/(-)-Diobolignans A to C possessed a dioxane ring between the benzene ring and the propyl side chain, while (+)/(-)-diobolignans D to F possessed a furan ring. Meanwhile, (+)/(-)-diobolignans B and C, as well as (+)/(-)-diobolignans E and F, were two epimeric pairs of enantiomers, respectively. Their structures were determined by extensive analyses of HRESIMS, UV, IR, NMR and electronic circular dichroism (ECD) calculations. The bioassay showed (+)-diobolignan A displayed cytotoxic activities against human cancer cell lines HGC27 and HT29 with the IC50 values of 9.43 and 9.45 mu M, respectively. In addition, (-)-diobolignan A and (+/-)-diobolignan E showed neuroprotective effect on glutamic acid-induced cellular damage in SK-N-SH cell.
Jo, Yang HeeLee, SolipYeon, Sang WonRyu, Se Hwan...
9页
查看更多>>摘要：The composition of a plant, together with its efficacy, vary depending on its maturity and plant parts. In this study, the chemical constituents of immature fruits of Maclura tricuspidata (Moraceae) were investigated together with their anti-diabetic and antioxidant effects. A total of 34 compounds were isolated from the immature fruits of M. tricuspidata using various chromatographic methods. Structure elucidation using extensive spectroscopic analysis led to the characterization of isolated compounds as isoflavonoids with prenyl substituents. Among them, macluraisoflavones A-O were first isolated from nature. The anti-diabetic and antioxidant activity of the isolated compounds were also suggested by alpha-glucosidase inhibitory activity and DPPH radical scavenging activity, respectively. In particular, macluraisoflavone I, an isoflavonoid with 2,2-dimethylpyran and 2-hydroperoxy-3-methylbut-3-enyl moieties, showed potent alpha-glucosidase inhibitory activity and DPPH radical scavenging activity. Further molecular docking analysis suggested hydrogen bond and alkyl interactions between alpha-glucosidase and macluraisoflavone I. Therefore, the immature fruits of M. tricuspidata can be used as an important natural product with antioxidant and anti-diabetic properties.
查看更多>>摘要：Jellynolide A, an unreported bicyclic diterpenoid with an unprecedented penta-substituted carbon skeleton which implied an irregular biogenic pathway, together with four pairs of rare phosphate triesters, (+/-)-pokepola ester B-E, one undescribed related racemic furanoterpenoid, (+/-)-sponalisolide C, one undescribed furanoterpenoid, (-)-sponalisolide D, and two known (+/-)-sponalisolide B and dendrolasin carboxylic acid were isolated from the aquaculture Spongia officinalis L. Their structures were elucidated by comprehensive spectroscopic analysis, quantum chemical calculation of NMR parameters, and electronic circular dichroism (ECD). The plausible biosynthetic pathway of jellynolide A was proposed. (+/-)-Pokepola ester C exhibited significant inhibition against Wnt, HIF1 signaling pathways. (+)-Pokepola ester B and (-)-pokepola ester D showed moderate cytotoxicity activities.
NSTL
Elsevier