11C-labeling of 20(S)-protopanaxadiol, an aglycon of ginsenoside, based on the use of Pd(0)-mediated rapid C-[11C]methylation of boronic precursors.

IF 2.2 4区 医学 Q3 CHEMISTRY, MEDICINAL
Bioorganic & Medicinal Chemistry Letters Pub Date : 2025-12-01 Epub Date: 2025-08-05 DOI:10.1016/j.bmcl.2025.130356
Yoshiki Ooshima, Hiroko Koyama, Aya Ogata, Hiroshi Ikenuma, Takashi Yamada, Hiroyuki Kojima, Takashi Kato, Yasuyuki Kimura, Masaaki Suzuki
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引用次数: 0

Abstract

Ginsenosides, the pharmacologically active components of Panax ginseng, are widely used in herbal medicine and reportedly exert diverse biological effects, including anticancer, anti-inflammatory, and neuroprotective activities. However, their pharmacological mechanisms remain poorly understood, owing to the lack of chemical probes suitable for in vivo analyses. Herein, we report the development of a 11C radiolabeling of 20(S)-protopanaxadiol (PPD), a major aglycone-type active ginsenoside metabolite, for positron emission tomography (PET) imaging. For the 11C labeling of PPD, we focused on the terminal vinyl methyl group of the dammarane-type triterpene backbone, a common structural element found in ginsenosides. A boronic precursor applicable for rapid 11C-methylation was efficiently synthesized via steps focusing on the controlled cross-metathesis of an internal olefin. The subsequent Pd(0)-mediated rapid 11C-methylation was conducted in N,N-dimethylformamide (DMF)/H₂O using [Pd₂(dba)₃], P(o-tolyl)₃, and sodium ascorbate, which functioned as a base and a radical scavenger. After formulation, the resulting [11C]PPD was obtained in a decay-corrected radiochemical yield of 15 ± 2 % (n = 3), with a total radioactivity of 1.0 ± 0.3 GBq (n = 3) and molar activity of 124 ± 7 GBq/μmol (n = 3). Radiochemical purity was ≥99 %, and the total synthesis time was 29 min. Using [11C]PPD, PET imaging of the brains of healthy rats and abdomens of healthy mice demonstrated low brain uptake and pronouncedly clear hepatobiliary excretion of radiolabeled species. These findings may provide a foundation for the general labeling of ginsenoside structures with 11C radioisotopes, thereby enabling systematic in vivo pharmacokinetic analyses of PPD derivatives to advance ginsenoside-based drug development.

基于Pd(0)介导的硼前体快速C-[11C]甲基化,对20(S)-原人参二醇(人参皂苷的糖基)进行11C标记。
人参皂苷是人参的药理活性成分,被广泛应用于草药中,据报道具有多种生物效应,包括抗癌、抗炎和神经保护活性。然而,由于缺乏适合体内分析的化学探针,它们的药理机制仍然知之甚少。在此,我们报道了一种用于正电子发射断层扫描(PET)成像的20(S)-原人参二醇(PPD)的11C放射性标记的发展,PPD是一种主要的苷基型活性人参皂苷代谢物。对于PPD的11C标记,我们重点关注了达玛烷型三萜主链末端的乙烯基甲基,这是人参皂苷中常见的结构元素。通过控制内烯烃的交叉复合,合成了一种适用于11c甲基化的硼前体。随后Pd(0)介导的快速11c甲基化在N,N-二甲基甲酰胺(DMF)/H₂O中进行,使用[Pd₂(dba)₃],P(O - toyl)₃和抗坏血酸钠,它作为碱和自由基清除剂。配方后,生成的c[11]获得了产后抑郁症在decay-corrected放射化学产量15 ±2  % (n = 3),总放射性 1.0±0.3  GBq (n = 3)和摩尔活动124年 ±7  GBq /μ摩尔(n = 3)。放射化学纯度≥99 %,总合成时间29 min。使用[11C]PPD,健康大鼠的大脑和健康小鼠的腹部PET成像显示低脑摄取和明显清除放射性标记物种的肝胆排泄。这些发现可能为用11C放射性同位素标记人参皂苷结构提供了基础,从而能够系统地分析PPD衍生物的体内药代动力学,从而推进基于人参皂苷的药物开发。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
CiteScore
5.70
自引率
3.70%
发文量
463
审稿时长
27 days
期刊介绍: Bioorganic & Medicinal Chemistry Letters presents preliminary experimental or theoretical research results of outstanding significance and timeliness on all aspects of science at the interface of chemistry and biology and on major advances in drug design and development. The journal publishes articles in the form of communications reporting experimental or theoretical results of special interest, and strives to provide maximum dissemination to a large, international audience.
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