Department of Cellular Microbiology, University of Hohenheim, 70599 Stuttgart, Germany.
Department of Internal Medicine VIII, University Hospital Tuebingen, 72076 Tuebingen, Germany; Department of Nutritional Biochemistry, University of Hohenheim, 70599 Stuttgart, Germany.
Phytomedicine. 2024 Jan;123:155176. doi: 10.1016/j.phymed.2023.155176. Epub 2023 Oct 30.
Selected natural compounds exhibit very good antiviral properties. Especially, the medicinal plant Humulus lupulus (hop) contains several secondary plant metabolites some of which have previously shown antiviral activities. Among them, the prenylated chalcone xanthohumol (XN) demonstrated to be a potent inhibitor of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) main protease (M).
HYPOTHESIS/PURPOSE: Following the finding that xanthohumol (XN) is a potent inhibitor of SARS-CoV-2 M, the effect of XN and its major derivatives isoxanthohumol (IXN), 6-prenylnaringenin (6-PN), and 8-prenylnaringenin (8-PN) from hops on SARS-CoV-2 papain-like protease (PL) were investigated.
The modulatory effect of the hop compounds on PL were studied first in silico and then in vitro. In addition, the actual effect of hop compounds on the replication of SARS-CoV-2 in host cells was investigated.
In silico docking analysis was used to predict the binding affinity of hop compounds to the active site of PL. A recombinant PL was cloned, purified, characterized, and analyzed by small-angle X-ray scattering (SAXS), deISGylation assays, and kinetic analyses. Antiviral activity of hop compounds was assessed using the fluorescently labeled wildtype SARS-CoV-2 (icSARS-CoV-2-mNG) in Caco-2 host cells.
Our in silico docking suggests that the purified hop compounds bind to the active site of SARS-CoV-2 PL blocking the access of its natural substrates. The hop-derived compounds inhibit SARS-CoV-2 PL with half maximal inhibitory concentration (IC) values in the range of 59-162 µM. Furthermore, we demonstrate that XN and 6-PN, in particular, impede viral replication with IC values of 3.3 µM and 7.3 µM, respectively.
In addition to the already known inhibition of M by XN, our results show, for the first time, that hop-derived compounds target also SARS-CoV-2 PL which is a promising therapeutic target as it contributes to both viral replication and modulation of the immune system. These findings support the possibility to develop new hop-derived antiviral drugs targeting human coronaviruses.
某些天然化合物具有很好的抗病毒特性。特别是药用植物蛇麻（啤酒花）含有几种次级植物代谢物，其中一些先前已显示出抗病毒活性。其中，类异戊二烯查尔酮黄腐醇（XN）被证明是严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）主要蛋白酶（M）的有效抑制剂。
假设/目的：鉴于黄腐醇（XN）是 SARS-CoV-2 M 的有效抑制剂，本研究旨在研究啤酒花中的黄腐醇（XN）及其主要衍生物异黄腐醇（IXN）、6- 异戊烯基柚皮素（6-PN）和 8- 异戊烯基柚皮素（8-PN）对 SARS-CoV-2 木瓜蛋白酶样蛋白酶（PL）的作用。
首先在计算机上研究了啤酒花化合物对 PL 的调节作用，然后进行了体外研究。此外，还研究了啤酒花化合物对宿主细胞中 SARS-CoV-2 复制的实际影响。
使用计算机对接分析预测啤酒花化合物与 PL 活性位点的结合亲和力。克隆、纯化、表征重组 PL，并通过小角 X 射线散射（SAXS）、脱泛素化测定和动力学分析进行分析。使用荧光标记的野生型 SARS-CoV-2（icSARS-CoV-2-mNG）在 Caco-2 宿主细胞中评估啤酒花化合物的抗病毒活性。
计算机对接提示，纯化的啤酒花化合物与 SARS-CoV-2 PL 的活性位点结合，阻止其天然底物进入。啤酒花衍生化合物对 SARS-CoV-2 PL 的半数最大抑制浓度（IC）值在 59-162µM 范围内。此外，我们还证明 XN 和 6-PN，特别是，分别以 3.3µM 和 7.3µM 的 IC 值抑制病毒复制。
除了已知的 XN 对 M 的抑制作用外，我们的结果首次表明，啤酒花衍生化合物还靶向 SARS-CoV-2 PL，这是一个有前途的治疗靶点，因为它既有助于病毒复制，又有助于调节免疫系统。这些发现支持开发针对人类冠状病毒的新型啤酒花衍生抗病毒药物的可能性。
