Table 2.

Study on the in vitro activity of flavonoids.

Compound	In Vitro Models	Conc.	Effects	Mechanism of Action	References
Baicalin	HepG2 cells	16 μM	Pneumonia	Inhibits NLRP3 inflammatory vesicles	[128]
	Rat IEC-6 cells	10.0 μg/mL	Inflammatory bowel disease	Inhibits IL-6 and TNF-α inflammatory factor levels	[129]
	KOPN-8, RCH-ACV, SEM, RS4-11, NALM-6	10 mg/mL	Acute B-lymphoblastic leukemia	Inhibits the glycogen synthase kinase 3β and induces cell cycle arrest by upregulating p27Kip1	[130]
	MCF-7 and MDA-MB-231 cells	30 μM	Breast cancer	Inhibits breast cancer cell proliferation and induces G1/S arrest in cells	[131]
	Vero, BHK-21, and HEK 293T cells	100 μM	Chikungunya virus	—	[132]
Baicalein and baicalin	Vero CCL-81 cells	20 μM	SARS-CoV-2	Inhibits SARS-CoV-2 RNA-dependent RNA polymerase activity	[105]
Baicalein	Vero E6 cell	>2.0 μM	COVID-19	Inhibits virus replication in vivo and reduces serum levels of IL-1β and TNF-α	[133]
	Vero cell lines	50 μM	SARS-CoV-2	Inhibits SARS-CoV-2 replication and its 3C-like protease	[105]
	HCT116 cells	50 μM	Colorectal cancer	Induces apoptosis in human colon cancer cells	[134]
Silymarin	Vero cells	749.70 µg/mL	Dengue virus	Binds to the surface protein of the virus to prevent entry into the cell	[70]
Luteolin	ARPE-19 cells	50 μM	Age-related macular degeneration	Decreases levels of IL− 8 and IL− 6	[135]
	MDCK cells and Vero cells	From 3.75 to 240 μM	Influenza A virus	Inhibits the expression of β-COP protein	[136]
	Enzymatic inhibition assay	4.6 μM	COVID-19	Inhibits SARS-CoV-2 RNA-dependent RNA polymerase activity	[25]
EGCG	Peripheral blood lymphocytes	50 μM	HIV	—	[137]
	live SARS-CoV-2 strain	1 μg/mL	SARS-CoV-2	Inhibits Nsp15 activity	[111]
	E. coli	7.58 μg/ mL	SARS-CoV-2	Inhibits the activity of 3CLpro	[112]
Formononetin	Vero cells	14.91 μmol/L	Enterovirus 71	Inhibits EV71-induced COX-2 expression and PGE2 production via MAPKs pathway	[68]
Biochanin A	A549 cells	5 μM	H5N1 influenza A viruses	Interferes with AKT, ERK 1/2, and NFκB activation to inhibit viral replication	[65]
Quercetin	T-REx™-293 cell line	10 μg/mL	HCV	Inhibits NS3 protease, thereby inhibiting viral replication	[138]
Naringenin	Huh-7.5 cells	25 μM	HCV	Reduces production of intracellular viral proteins	[139]