Lichen-Derived Diffractaic Acid Inhibited Dengue Virus Replication in a Cell-Based System

Abstract

Dengue is a mosquito-borne flavivirus that causes 21,000 deaths annually. Depsides and depsidones of lichens have previously been reported to be antimicrobials. In this study, our objective was to identify lichen-derived depsides and depsidones as dengue virus inhibitors. The 18 depsides and depsidones of Usnea baileyi, Usnea aciculifera, Parmotrema dilatatum, and Parmotrema tsavoense were tested against dengue virus serotype 2. Two depsides and one depsidone inhibited dengue virus serotype 2 without any apparent cytotoxicity. Diffractaic acid, barbatic acid, and Parmosidone C were three active compounds further characterized for their efficacies (EC50), cytotoxicities (CC50), and selectivity index (SI; CC50/EC50). Their EC50 (SI) values were 2.43 ± 0.19 (20.59), 0.91 ± 0.15 (13.33), and 17.42 ± 3.21 (8.95) μM, respectively. Diffractaic acid showed the highest selectivity index, and similar efficacies were also found in dengue serotypes 1–4, Zika, and chikungunya viruses. Cell-based studies revealed that the target was mainly in the late stage with replication and the formation of infectious particles. This report highlights that a lichen-derived diffractaic acid could become a mosquito-borne antiviral lead as its selectivity indices ranged from 8.07 to 20.59 with a proposed target at viral replication.

Antiviral Activity of Catechin against Dengue Virus Infection

“…Flavonoids, a significant subclass of polyphenols, are present in various food and plant species. Due to their diverse pharmacological activities, including antiviral, anti-bacterial, antioxidant, and anti-inflammatory properties, a growing number of studies have been carried out on this class of compounds [ 12 , 23 , 24 , 25 , 26 ]. Catechins are flavonoid derivatives present in food and medicinal plants.…”