Center for Food Safety, Department of Food Science and Technology, University of Georgia, Griffin Campus, 1109 Experiment Street, Griffin, GA, 30223, USA.
Food Environ Virol. 2024 Jun;16(2):159-170. doi: 10.1007/s12560-023-09581-0. Epub 2024 Jan 31.
SARS-CoV-2 infects the oral mucosa and is shed in salivary fluids. Traditionally, tea has been used by various cultures to treat respiratory ailments. The objective of this study was to identify commercially available teas that can rapidly inactivate infectious SARS-CoV-2 in saliva. Initially, tea (n = 24) was prepared as 40 mg/mL infusions and incubated with SARS-CoV-2 resuspended in water, for 5 min at 37 °C. Then, five teas that showed >3 log reduction in virus infectivity were further investigated at 40 and 10 mg/mL infusions for 60 and 10 s contact time with SARS-CoV-2 resuspended in saliva. Tea polyphenols were measured using the Folin-Ciocalteu assay. SARS-CoV-2 infectivity was quantified on Vero-E6 cell line using TCID50 assay. At 10 mg/mL infusion, black tea showed the highest reduction (3 log, i.e., 99.9%) of infectious SARS-CoV-2 within 10 s. Green, mint medley, eucalyptus-mint, and raspberry zinger teas showed similar inactivation of SARS-CoV-2 (1.5-2 log, i.e., 96-99% reduction). At 40 mg/mL infusions, all five teas showed >3 log reduction in virus infectivity within 10 s. Tea polyphenol but not pH was significantly correlated to virus reduction. Time-of-addition assay revealed that the five teas displayed preventive effects (0.5-1 log, i.e., 68-90% reduction) against SARS-CoV-2 infection of Vero-E6 cells as well as during post-virus infection (1.2-1.9 log, i.e., 94-98%). However, the highest inhibitory effect was observed when the teas were added at the time of virus infection (2-3 log, i.e., 99-99.9%). Our results provide insights into a rapid at-home intervention (tea drinking or gargling) to reduce infectious SARS-CoV-2 load in the oral cavity which might also mitigate infection of the oral mucosa.
SARS-CoV-2 感染口腔黏膜，并从唾液中排出。传统上，各种文化都用茶来治疗呼吸道疾病。本研究的目的是鉴定可快速灭活唾液中传染性 SARS-CoV-2 的市售茶。最初，将茶（n=24）制备成 40mg/mL 的浸液，并在 37°C 下与悬浮在水中的 SARS-CoV-2 孵育 5 分钟。然后，进一步研究了在 40 和 10mg/mL 浸液中，与悬浮在唾液中的 SARS-CoV-2 接触 60 和 10 秒时，可使病毒感染力降低 3 个对数级以上的 5 种茶。使用 Folin-Ciocalteu 法测定茶多酚。使用 TCID50 测定法在 Vero-E6 细胞系上定量 SARS-CoV-2 感染力。在 10mg/mL 浸液中，红茶在 10 秒内对传染性 SARS-CoV-2 的降低幅度最大（3 个对数级，即 99.9%）。绿茶、薄荷混合茶、桉树薄荷茶和覆盆子生姜茶对 SARS-CoV-2 的灭活作用相似（1.5-2 个对数级，即 96-99%的降低）。在 40mg/mL 浸液中，五种茶在 10 秒内均可使病毒感染力降低 3 个对数级以上。茶多酚但不是 pH 值与病毒减少显著相关。添加时间测定表明，五种茶对 SARS-CoV-2 感染 Vero-E6 细胞以及病毒感染后（1.2-1.9 个对数级，即 94-98%）均显示出预防作用（0.5-1 个对数级，即 68-90%的降低）。然而，当茶在病毒感染时添加时，观察到最高的抑制作用（2-3 个对数级，即 99-99.9%）。我们的结果为在家中进行快速干预（饮茶或漱口）以减少口腔中传染性 SARS-CoV-2 负荷提供了思路，这也可能减轻口腔黏膜感染。
