Quercetin antiviral activity

Choi HJ, Kim JH, Lee CH, Ahn YJ, Song JH, Baek SH, Kwon DH. (2009) Antiviral activity of quercetin 7-rhamnoside against porcine epidemic diarrhea virus. Antiviral Res 81 77-81. 

In one of our recent studies, we examined antimicrobial and antiviral activities of four flavonoid derivatives, namely, scandenone (5), tiliro-side (6), quercetin-3,7-O-a-L-dirhamnoside (7), and kaempferol 3,7-O-a-L-dirhamnoside (8) as shown in Fig. 2. These were tested against E. coli, P. aeruginosa, Proteus mirabilis, Klebsiella pneumoniae, Acinetobacter bau-mannii, S. aureus, B. subtilis, and Enterococcus faecalis, as well as the fungus Candida albicans by the microdilution method [26]. In addition, both DNA virus Herpes simplex (HSV) and RNA virus Parainfluenza (PI-3) were employed for antiviral assessment of the compounds using Madin-Darby bovine kidney (MDBK) and Vero cell lines. 

Flavonoids also showed, to some extent, some antifungal and antiviral activity. In this case, there is an important structure-activity relationship. The flavonol quercetin and the flavanone hesperidin exhibit inhibition activity towards the infective capacity and/or replication of herpes simplex type viruses and polio viruses, while the flavanone naringenin totally lacks this ability [124]. For researchers the impossibility to dissociate, the viruses from the flavonol quercetin after 1 hour of interaction, either by dialysis or ultracentrifugation suggests the formation of quercetin-virus complexes, which may have lost the ability to induce infection. With respect to the antiviral activity of the methoxylated flavones, this is strongly related to a substitution pattern based on... 

The compound does not directly inactivate the virus, but it was most effective when present in the early stages of virus replication. Although T2 was not active in vivo, its diacetyl derivative 1 (Ro 09-0298) was orally effective in protecting mice from lethal Infections with coxsackievirus B1.53 The closely related natural product, quercetin, has antiviral activity both in vitro and in vivo.5 1 Additional studies with quercetin against Mengo M virus Infected mice have confirmed previous reports of its oral... 

Antiviral activity Rabies virus Quercetin, Rutin... 

Biological activities ascribed to quercetin include its antiviral, anti-inflammatory, antiproliferative, and antimicrobial properties. Quercetin is found in high concentrations in commonly consumed foods such as onions, apples, kale, red wine, and green and black teas, and other foods shown in the following table. 

Antioxidant activity of flavonol derivatives kaempferol, quercetin, morin, myricetin, and rutin has been suggested to explain their anti-inflammatory, antiallergic, antiviral, as well as anticancer activities. It has been confirmed that quercetin, kaempferol, and apigenin (Fig. 4) can induce cellular antioxidant system by increasing intracellular glutathione levels [83]. 

---