Department of Paraclinical Sciences, Phytomedicine Programme, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.
Present address: Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg, 2193, South Africa.
BMC Complement Med Ther. 2021 Mar 16;21(1):92. doi: 10.1186/s12906-021-03250-0.
Some viruses play a key role in the disturbance of the digestive system. The common viruses which cause infectious diarrhoea (gastroenteritis) include astrovirus, caliciviruses, coronavirus and torovirus which are single-stranded RNA viruses. Influenza A virus (H1N1) also causes diarrhoea in addition to being associated with respiratory symptoms. In preliminary studies, Newtonia hildebrandtii and N. buchananii leaf extracts had good antibacterial activity against some bacteria implicated in causing diarrhoea. The aim of this study was to evaluate the anti-influenza activity of two Newtonia species extracts and the isolated compound (myricitrin).
N. hildebrandtii and N. buchananii acetone, and MeOH: DCM (methanol-dichloromethane) leaf and stem extracts, and an antibacterial compound myricetin-3-o-rhamnoside (myricitrin), isolated from N. buchananii, were evaluated for their antiviral efficacy against influenza A virus (IAV) PR8/34/H1N1 as a model organism. The MTT and hemagglutination assays were used to assess the extracts and compound interference with cell viability and viral surface HA glycoprotein. The quantitative real-time PCR was performed to assess the viral load.
Plant extracts of N. hildebrandtii and N. buchananii were effective against IAV. The extracts in combination with H1N1 showed highly significant antiviral activity (P < 0.01) and maintained cell viabilities (P < 0.05). Myricitrin was non-cytotoxic at concentration 104 μg/ml. Myricitrin was most effective against IAV in a co-penetration combined treatment, thereby confirming the inhibitory effect of this compound in the viral attachment and entry stages. Myricitrin treatment also resulted in the highest viability of the cells in co-penetration treatment. The activity of myricitrin indicates the potential of the extracts in controlling viral infection at the attachment stage. The antiviral effect of myricitrin on IAV load in MDCK cell culture was confirmed using quantitative real-time PCR.
Data from this study support further research and development on Newtonia hildebrandtii, Newtonia buchananii and myricitrin to address diarrhoea and related conditions caused by viruses in both human and veterinary medicine. Further work needs to be conducted on the activity of the extracts and the purified compound on other viruses of importance which have similar symptoms to influenza virus such as the coronavirus which led to a recent global pandemic.
有些病毒在扰乱消化系统方面起着关键作用。引起感染性腹泻（肠胃炎）的常见病毒包括星状病毒、杯状病毒、冠状病毒和环曲病毒，它们都是单链 RNA 病毒。甲型流感病毒（H1N1）除了与呼吸道症状有关外，也会引起腹泻。在初步研究中，Newtonia hildebrandtii 和 N. buchananii 叶提取物对引起腹泻的一些细菌具有良好的抗菌活性。本研究旨在评估两种 Newtonia 种提取物和分离化合物（杨梅素-3-O-鼠李糖苷）的抗流感病毒活性。
评估了 Newtonia hildebrandtii 和 N. buchananii 丙酮、MeOH：DCM（甲醇-二氯甲烷）叶和茎提取物以及从 N. buchananii 中分离出的抗菌化合物杨梅素-3-O-鼠李糖苷（杨梅素-3-O-鼠李糖苷）对甲型流感病毒（IAV）PR8/34/H1N1 的抗病毒功效。MTT 和血凝试验用于评估提取物和化合物对细胞活力和病毒表面 HA 糖蛋白的干扰。通过定量实时 PCR 评估病毒载量。
Newtonia hildebrandtii 和 N. buchananii 的植物提取物对 IAV 有效。提取物与 H1N1 联合使用表现出高度显著的抗病毒活性（P<0.01），并保持细胞活力（P<0.05）。在浓度为 104μg/ml 时，杨梅素-3-O-鼠李糖苷无细胞毒性。杨梅素-3-O-鼠李糖苷在共渗透联合治疗中对 IAV 最有效，从而证实了该化合物在病毒附着和进入阶段的抑制作用。杨梅素-3-O-鼠李糖苷处理还导致共渗透处理中细胞活力最高。杨梅素-3-O-鼠李糖苷的活性表明提取物在控制病毒感染附着阶段方面具有潜力。定量实时 PCR 证实了杨梅素-3-O-鼠李糖苷对 MDCK 细胞培养中 IAV 负荷的抗病毒作用。
本研究的数据支持对 Newtonia hildebrandtii、Newtonia buchananii 和杨梅素-3-O-鼠李糖苷进行进一步的研究和开发，以解决人类和兽医医学中由病毒引起的腹泻和相关疾病。需要进一步研究提取物和纯化化合物对其他具有类似流感病毒症状的重要病毒的活性，如导致最近全球大流行的冠状病毒。
