Department of Food Science, University of Tennessee-Knoxville, Knoxville, TN, USA.
Food Environ Virol. 2023 Jun;15(2):167-175. doi: 10.1007/s12560-023-09550-7. Epub 2023 Mar 15.
Aqueous extracts of Quillaja saponaria Molina are US FDA approved as food additives in beverages with known antiviral activity. Due to lack of commercially available vaccines against human noroviruses (HNoVs), alternate methods to prevent their spread and the subsequent emergence of variant strains are being researched. Furthermore, HNoVs are not yet culturable at high enough titers to determine inactivation, therefore surrogates continue to be used. This research analyzed the effect of aqueous Quillaja saponaria extracts (QE) against HNoV surrogates, Tulane virus (TV), murine norovirus (MNV-1), and feline calicivirus (FCV-F9) at room temperature (RT) and 37 °C. Viruses (~ 5 log PFU/mL) were individually treated with 1:1 or 1:5 (v/v) diluted QE (pH ~ 3.75), malic acid control (pH 3.0) or phosphate-buffered saline (pH 7.2, as control) at 37 °C or RT for up to 6 h. Individual treatments were replicated three times using duplicate plaque assays for each treatment. FCV-F9 at ~ 5 log PFU/mL was not detectable after 15 min by 1:1 QE at 37 °C and RT. At RT, 1:5 QE lowered FCV-F9 titers by 2.05, 2.14 and 2.74 log PFU/mL after 0.5 h, 1 h and 2 h, respectively. MNV-1 showed marginal reduction of < 1 log PFU/mL after 15 min with 1:1 or 1:5 QE at 37 °C without any significant reduction at RT, while TV titers decreased by 2.2 log PFU/mL after 30 min and were undetectable after 3 h at 37 °C. Longer incubation with higher QE concentrations may be required for improved antiviral activity against MNV-1 and TV.
皂树皮的水提取物已被美国食品和药物管理局批准为食品添加剂，用于具有已知抗病毒活性的饮料中。由于缺乏针对人类诺如病毒（HNoV）的商业上可用的疫苗，因此正在研究预防其传播和随后出现变异株的替代方法。此外，HNoV 目前还不能以足够高的滴度进行培养以确定其失活，因此仍在继续使用替代物。本研究分析了在室温（RT）和 37°C 下，皂树皮水提取物（QE）对 HNoV 替代物、Tulane 病毒（TV）、鼠诺如病毒（MNV-1）和猫杯状病毒（FCV-F9）的影响。将病毒（~5 log PFU/mL）分别用 1:1 或 1:5（v/v）稀释的 QE（pH ~3.75）、苹果酸对照（pH 3.0）或磷酸盐缓冲盐水（pH 7.2，作为对照）在 37°C 或 RT 下处理长达 6 小时。每种处理均重复三次，使用每种处理的重复噬斑测定法进行三次复制。在 RT 下，1:1 QE 在 37°C 和 RT 下 15 分钟后，FCV-F9 的滴度降低了 2.05、2.14 和 2.74 log PFU/mL。在 RT 下，1:5 QE 在 0.5 小时、1 小时和 2 小时后分别使 FCV-F9 滴度降低了 2.05、2.14 和 2.74 log PFU/mL。MNV-1 在 37°C 下用 1:1 或 1:5 QE 处理 15 分钟后仅略有减少<1 log PFU/mL，而在 RT 下没有任何显著减少，而 TV 滴度在 30 分钟后降低了 2.2 log PFU/mL，在 37°C 下 3 小时后无法检测到。可能需要更长时间的孵育和更高浓度的 QE 以提高对 MNV-1 和 TV 的抗病毒活性。
