Table 1.

Antiviral activities of flavonoids against swine viruses.

Flavonoid	Structure	Virus	Treatment Time	Experimental Model	Effective Concentration	Inhibitory Phase	Mechanism	Reference
epigallocatechin-3-gallate (EGCG)		PRRSV	Pre	In vitro	125 μM	Early phase	Block PRRSV binding to cells, reduce pro-inflammatory factors, and disturb lipid metabolism	[21,22,23,24]
		PRV	Pre	In vivo/in vitro	50 μM (in vitro) 40 mg/kg (in vivo)	Multiple steps	Inhibit PRV adsorption, entry, and replication	[25,26]
		PCV2	Pre	In silico/in vitro	100 μM	Early phase	Interacts with heparan sulfate to competitively inhibit capsid binding	[27]
		H9N2	Post	In vivo	10 mg/kg	Multiple steps	Reduce Organs damage, inflammation, and virus titer	[28]
quercetin		PRRSV	Post	In vivo	10 mg/kg 100 μM in vivo	Multiple steps	Cross protective efficacy and inhibit the activity of Hsp70	[29,30]
		PEDV	Pre	In vitro	100 μM	Early phase	Inhibit the activity of PEDV 3CL protease	[31,32,33,34]
		PRV	Pre Simultaneity	In vitro In vivo	50 μM (in vitro) 1.51 μg (in vivo)	Early phase	Interacting with the viral gD protein. Reducing the secretion of reactive oxygen species induced by PRV.	[35,36]
kaempferol		ASFV	Simultaneity Post	In vitro	20 μg/mL	Early phase	Induced autophagy	[37]
		PRV		In vitro	240 mg/kg	Early phase	Reduced the expression level of viral IE180 and inhibit viral replication	[25]
		H9N2	Post	In vivo	15 mg/kg	Later phase	Inhibit the NF-κB and MAPKs pathways mediated by TLR4/MyD88 NF-κB	[38]
hyperoside		PEDV	Pre	in vitro	20 μM	Later phase	Inhibited N protein-induced S phase cell cycle arrest	[39]
rutin		PRRSV	Post	In vitro	7.8 μg/mL	Later phase	Regulate inflammation and suppress PRRSV replication	[21]
		PRV	Post	In vitro	40 μg/mL	Later phase	Inhibit the activation of NF-κB and MAPK pathways	[40]
total flavonoids of S. suberectus Dunn (TFSD)	-	PCV2	Post	In vitro/In vivo	50–100 μg/mL (in vitro)/ 50–100 mg/kg (in vivo)	Later phase	Anti-oxidation and immunomodulatory effects	[41,42]
(+)-catechin		TGEV	Post	In vitro	80 μM	Later phase	Anti-oxidation	[43,44]
myricetin		ASFV	Simultaneity	In vitro	20 μM	Early phase	Interaction of 3, 4, 5-trihydroxyphenyl with ASFV protease	[45]
myricitrin		ASFV	Simultaneity	In vitro	40 μM	Later phase	Interaction of 3, 4, 5-trihydroxyphenyl with ASFV protease	[45]
genistein		ASFV	Pre	In vitro	50 μM	Early phase	Disrupt the synthesis of viral DNA	[46]
genkwanin		ASFV	Simultaneity	In silico/in vitro	40 μM	Early phase, later phase	Inhibition of ASFV entry and release phases	[47,48]
apigenin		ASFV	Pre	In vitro	50 μM	Early phase, later phase	Expression of 25-kD virus protein was inhibited	[47,48]
quercetin 7-rhamnoside (Q7R)	-	PEDV	Simultaneity	In vitro	10 μg/mL	Early phase	Inhibit the early stage of viral replication	[34]
chalcone	-	H1N1	Pre	In vitro	2.49 ± 0.14 μg/mL	Later phase	Noncompetitive inhibitors of H1N1 neuraminidase	[49,50,51]
Isobavachalcone (IBC)		PRRSV	Post	In vitro	<15 μM	Later phase	Interference with RNA synthesis	[52]
		PRV	Simultaneity	In vitro	25.6 μM	Later phase	PRV replication was inhibited at the intercellular fusion stage	[53]
Xanthohumol (Xn)		PRRSV	Pre	In vivo/in vitro	15 μM	Later phase	Nrf2-HMOX1 axis	[54,55]
Isoflavones (ISF)		PRRSV	Post	In vivo	1600 mg/kg	Later phase	Supported immune responses	[56,57,58]
Puerarin		PEDV	Post	In vivo	0.5 mg/kg	Later phase	Alleviate systemic inflammation	[59,60]