Plant-derived lignans as potential antiviral agents: a systematic review.

Medicinal plants are one of the most important sources of antiviral agents and lead compounds. Lignans are a large class of natural compounds comprising two phenyl propane units. Many of them have demonstrated biological activities, and some of them have even been developed as therapeutic drugs. In this review, 630 lignans, including those obtained from medicinal plants and their chemical derivatives, were systematically reviewed for their antiviral activity and mechanism of action. The compounds discussed herein were published in articles between 1998 and 2020. The articles were identified using both database searches (e.g., Web of Science, Pub Med and Scifinder) using key words such as: antiviral activity, antiviral effects, lignans, HBV, HCV, HIV, HPV, HSV, JEV, SARS-CoV, RSV and influenza A virus, and directed searches of scholarly publisher's websites including ACS, Elsevier, Springer, Thieme, and Wiley. The compounds were classified on their structural characteristics as 1) arylnaphthalene lignans, 2) aryltetralin lignans, 3) dibenzylbutyrolactone lignans, 4) dibenzylbutane lignans, 5) tetrahydrofuranoid and tetrahydrofurofuranoid lignans, 6) benzofuran lignans, 7) neolignans, 8) dibenzocyclooctadiene lignans and homolignans, and 9) norlignans and other lignoids. Details on isolation and antiviral activities of the most active compounds within each class of lignan are discussed in detail, as are studies of synthetic lignans that provide structure-activity relationship information.

Impact of treatment delays on vitiligo during the COVID-19 pandemic: A retrospective study.

Due to the COVID-19 pandemic, routine treatments are delayed to some extent and their negative impacts have been widely reported. However, virtually nothing is known about vitiligo in the context of COVID-19. Therefore, we analyzed treatment delays and its impact on vitiligo, aiming to provide suggestions on vitiligo management within this special period. We performed a retrospective cohort study on 322 patients who visited our clinics at least 2 times from January to December 2020, and their medical records and photographs were reviewed. Patients were divided into normal (n = 155) and late group (n = 167) based on whether experienced treatment delays. As for the active cases, the late group showed higher progression rate than normal group (35 of 86 [40.7%] vs. 10 of 81 [12.3%]; p = 0.002). Moreover, we observed higher recurrence rate in delay group than those of normal group (26 of 81[32.1%] vs. 9 of 74 [12.2%]; p = 0.018) among stable cases. Further univariate and multivariate analysis determined treatment delays as the most important independent risk factor for disease progression and recurrence, and maintenance therapy (>2 years) as a protective factor against recurrence. This study, for the first time, revealed the independent adverse impact of treatment delays on the progression and recurrence of vitiligo and indicated the significance of continuous treatment for halting progression and long-term maintenance therapy for preventing recurrence for vitiligo, which should be highly valued in the management of vitiligo during the COVID-19 pandemic.