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Men R.-Z.,Shenyang Pharmaceutical University | Li N.,Shenyang Pharmaceutical University | Ding W.-J.,Zhejiang University | Hu Z.-J.,Zhejiang University | And 2 more authors.
Steroids | Year: 2014

The 95% ethanol extract of the whole plant of Physalis angulata Linn. afforded one new skeletal physalin named aminophysalin A (1) and one new naturally occurring 5β-hydroxy-6a-chloro-5,6-dihydrophysalin B (2), together with five known physalins (3-7). Their structures were elucidated through MS, IR, NMR spectroscopy analyses and X-ray crystallography. Aminophysalin A (1) had an absolutely unusual structural feature in the chemistry of physalins with a nitrogen atom. Compounds 1-7 were evaluated for quinone reductase activities in hepa 1c1c7 cells. Physalin H (6) showed strong quinone reductase induction activity with IR (Induction ratio, QR induction activity) value of 3.74 ± 0.02, using 4-bromoflavone as a positive control substance (2.17 ± 0.01, 10 μg/mL), while compounds 1, 2, 3, 5 showed weak quinone reductase induction activity. © 2014 Elsevier Inc. All rights reserved.

Ji L.,Zhejiang University | Yuan Y.,Zhejiang University | Ma Z.,Zhejiang University | Chen Z.,Chinese Traditional Medicine Hospital of Zhejiang Province | And 3 more authors.
Steroids | Year: 2013

In the present study, it was demonstrated that the dichloromethane extract of Physalis pubescens L. (DEPP) had weak potential quinone reductase (QR) inducing activity, but an UPLC-ESI-MS method with glutathione (GSH) as the substrate revealed that the DEPP had electrophiles (with an α,β- unsaturated ketone moiety). These electrophiles could induce quinone reductase (QR) activity, which might be attributed to the modification of the highly reactive cysteine residues in Keap1. Herein, four withanolides, including three new compounds physapubescin B (2), physapubescin C (3), physapubescin D (4), together with one known steroidal compound physapubescin (1) were isolated. Structures of these compounds were determined by spectroscopic analysis and that of physapubescin C (3) was confirmed by a combination of molecular modeling and quantum chemical DFT-GIAO calculations. Evaluation of the QR inducing activities of all withanolides indicated potent activities of compounds 1 and 2, which had a common a,b-unsaturated ketone moiety. © 2013 Elsevier Ltd. All rights reserved.

Ji L.,Zhejiang University | Yuan Y.,Zhejiang University | Luo L.,Zhejiang University | Chen Z.,Chinese Traditional Medicine Hospital of Zhejiang Province | And 3 more authors.
Steroids | Year: 2012

Michael reaction acceptors (MRAs) are a class of active molecules that are directly or indirectly involved in various cellular processes, including the regulation of many signaling pathways. In this study, the inducible nitric oxide synthase (iNOS) assay was used to demonstrate that the dichloromethane extract of Physalis alkekengi var. franchetii (DCEP) possesses anti-inflammatory activity that might be attributed to the modification of key cysteine residues in IKKβ by the MRAs in DCEP. To isolate these MRAs, glutathione (GSH) was employed, and a simple ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) screening method was developed to investigate the GSH conjugates with potential MRAs. Five physalins, including one new compound isophysalin A (2), together with four known steroidal compounds, physalin A (1), physalin O (3), physalin L (4) and physalin G (5), were isolated to evaluate the GSH conjugating abilities, and it was indicated that compounds 1, 2 and 3, which had a common α,β-unsaturated ketone moiety, exhibited conjugating abilities with GSH and also showed significant nitric oxide (NO) production inhibiting activities. The anti-inflammatory activities of compounds 1, 2 and 3 might be attributed to their targeting multiple cysteine residues on IKKβ; therefore, the alkylation of IKKβ by compound 1 was further studied by micrOTOF-MS. The result showed that six cysteine residues (C 59, C 179, C 299, C 370, C 412, and C 618) were alkylated, which indicated that IKKβ is a potential target for the anti-inflammatory activity of physalin A. © 2011 Elsevier Inc. All rights reserved.

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