In vitro: |
J Nat Prod., 2020 Dec 24;83(12):3536-3544. | Lipid-Lowering Activities of Cucurbitacins Isolated from Trichosanthes cucumeroides and Their Synthetic Derivatives[Pubmed: 33269591] | In the ongoing efforts to discover natural cholesterol-lowering compounds, dihydrocucurbitacin B, isolated from Trichosanthes cucumeroides roots, was found to promote LDL uptake by upregulating LDLR protein in a PCSK9-dependent process. In this study, an in-depth investigation of T. cucumeroides roots afforded 27 cucurbitacins (1-27), including seven new cucurbitacins (1-7), and their structures were elucidated by spectroscopic data analyses. In order to gain insight into their structure-activity relationship, cucurbitacin derivatives (B1-11 and DB1-11) were synthesized. Evaluation of lipid-lowering activities of these cucurbitacins by an LDL uptake assay in HepG2 cells revealed that most of the compounds improved the LDL uptake rate, among which hexanorisocucurbitacin D (6) and isocucurbitacin D (21) exhibited the highest activities (rates of 2.53 and 2.47, respectively), which were comparable to that of the positive control, nagilactone B (rate of 2.07). According to a mechanistic study by Western blot analysis, compounds 6 and 21 dose-dependently increased LDLR protein levels and reduced PCSK9 protein levels, representing promising new lipid-lowering drug candidates. | Toxins (Basel). 2022 Mar 16;14(3):212. | Analysis of Active Compounds Using Target Protein Cofilin-Cucurbitacins in Cytotoxic Plant Bryonia cretica[Pubmed: 35324709] | We examined a two-step target protein binding strategy that uses cofilin as the target protein to analyze the active constituents in Bryonia cretica. In the first step, we prepared the target protein, and used it to analyze the compounds binding to it in the second step. We used the methanolic extract of B. cretica as a library of possible active compounds. We conducted LC-MS analysis using information from our previous study. The peaks in the HPLC profile were identified as cucurbitacin D, isocucurbitacin D, and cucurbitacin I. As far as we know, there is no known study of the activity of isocucurbitacin D in this research field. Therefore, we examined the effects of isocucurbitacin D on cell proliferation and cofilin protein in human fibrosarcoma cell line HT1080 to confirm the effectiveness of this strategy. The cytotoxicity assay, the fibrous/globular actin ratio assay, and the immunoblotting analysis revealed that isocucurbitacin D showed a cytotoxic effect with disruption of target protein cofilin. The target protein binding strategy is a direct and straightforward method for finding new drug seeds from crude sources, such as natural plant extracts. |
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