Risk factors and on-site simulation of environmental transmission of SARS-CoV-2 in the largest wholesale market of Beijing, China.

From June 11, 2020, a surge in new cases of coronavirus disease 2019 (COVID-19) in the largest wholesale market of Beijing, the Xinfadi Market, leading to a second wave of COVID-19 in Beijing, China. Understanding the transmission modes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the personal behaviors and environmental factors contributing to viral transmission is of utmost important to curb COVID-19 rise. However, currently these are largely unknown in food markets. To this end, we completed field investigations and on-site simulations in areas with relatively high infection rates of COVID-19 at Xinfadi Market. We found that if goods were tainted or personnel in market was infected, normal transaction behaviors between sellers and customers, daily physiological activities, and marketing activities could lead to viral contamination and spread to the surroundings via fomite, droplet or aerosol routes. Environmental factors such as low temperature and high humidity, poor ventilation, and insufficient hygiene facilities and disinfection practices may contribute to viral transmission in Xinfadi Market. In addition, precautionary control strategies were also proposed to effectively reduce the clustering cases of COVID-19 in large-scale wholesale markets.

Novel secolignans from Peperomia dindygulensis and their inhibitory activities on JAK-STAT signaling pathways.

Nineteen secolignans (1-19), including five new ones (1-5), were isolated from the whole plant of Peperomia dindygulensis. Their structures including stereochemistry were determined by spectroscopic methods, in particular NMR and electronic CD (ECD) analysis. All the isolates were evaluated for their inhibitory activities against IFN-γ/STAT1 as well as IL-6/STAT3 signaling pathway by the method of Luciferase assay. Six 2-methene type secolignans (1, 2, 6-9) exhibited significant inhibitory activities against JAK-STAT pathways with the IC50 values both lower than 10µM.

Active components with inhibitory activities on IFN-γ/STAT1 and IL-6/STAT3 signaling pathways from Caulis Trachelospermi.

Initial investigation for new active herbal extract with inhibiting activity on JAK/STAT signaling pathway revealed that the extract of Caulis Trachelospermi, which was separated by 80% alcohol extraction and subsequent HP-20 macroporous resin column chromatography, was founded to strongly inhibit IFN-γ-induced STAT1-responsive luciferase activity (IFN-γ/STAT1) with IC50 value of 2.43 µg/mL as well as inhibiting IL-6-induced STAT3-responsive luciferase activity (IL-6/STAT3) with IC50 value of 1.38 µg/mL. Subsequent study on its active components led to the isolation and identification of two new dibenzylbutyrolactone lignans named 4-demethyltraxillaside (1) and nortrachelogenin 4-O-ß-D-glucopyranoside (2), together with six known compounds. The lignan compounds 1-4 together with other lignan compounds isolated in previous study were tested the activities on IFN-γ/STAT1 and IL-6/STAT3 pathways. The following result showed that the main components trachelogenin and arctigenin had corresponding activities on IFN-γ/STAT1 pathway with IC50 values of 3.14 µM and 9.46 µM as well as trachelogenin, arctigenin and matairesinol strongly inhibiting IL-6/STAT3 pathway with IC50 values of 3.63 µM, 6.47 µM and 2.92 µM, respectively.