Table 2.

In vitro antiviral activity of CQ and its derivatives on CoVs.

Drug	Virus	Cells	EC50 (μM)	SI	Main findings	Year	Ref
CQ	SARS-CoV	Vero E6	8·8 ± 1·2	30	↓ viral replication	2004	[104]
CQ	SARS-CoV	Vero E6	4.4 + 1·0	–	↓ viral replication	2005	[37]
CQ	SARS-CoV	Vero 76	1–5	2–20	↓ viral replication	2006	[105]
CQ	SARS-CoV	Vero	6.5 ± 3.2	>15	↓ viral replication	2006	[106]
CQ	SARS-CoV	Vero E6	4.1 ± 1.0	>31	↓ viral replication	2014	[107]
CQ-MP	SARS-CoV	Vero 76	4–6	3–8	↓ viral replication	2006	[105]
CQ-DP	SARS-CoV	Vero 76	3–8	2–10	↓ viral replication	2006	[105]
AMD	SARS-CoV	Vero 76	3–10	2–10	↓ viral replication	2006	[105]
HCQ	SARS-CoV	Vero	34 ± 5	>3	Ineffective	2006	[106]
FQ	SARS-CoV	Vero	1.4 ± 0.1	15	↓ viral replication	2006	[106]
HFQ	SARS-CoV	Vero	1.9–4.9	4–17	↓ viral replication	2006	[106]
CQ	MERS-CoV	Huh7	3.0 ± 1.1	19.4	↓ viral replication	2014	[107]
CQ	MERS-CoV	Vero E6	6.3	–	Ineffective	2018	[116]
CQ	SARS-CoV-2	Vero E6	1.13	>88.5	↓ viral replication	2020	[113]
CQ	SARS-CoV-2	Vero	5.47	–	↓ viral replication	2020	[112]
CQa	SARS-CoV-2	Vero E6	2.71–7.36	37.12–100.81	↓ viral replication	2020	[114]
HCQ	SARS-CoV-2	Vero	0.72	–	↓ viral replication	2020	[112]
HCQa	SARS-CoV-2	Vero E6	4.06–17.31	14.41–61.45	↓ viral replication	2020	[114]
CQ	HCoV-229E	L132	–	–	↓ viral replication	2008	[109]
CQ	HCoV-229E	Huh7	3.3 ± 1.2	>15	↓ viral replication	2014	[107]
CQ	HCoV-OC43	HRT-18	0.3 ± 0.0	1369	↓ viral replication	2009	[108]
CQ	MHV4	Murine cells	–	–	Ineffective	1991	[117]
CQ	MHV3	Murine MΦ	–	–	↓ viral replication	1966	[115]
CQ	F–CoV	CRFK	>0.8	–	↓ viral replication	2006	[106]
HCQ	F–CoV	CRFK	28 ± 27	–	Ineffective	2006	[106]
FQ	F–CoV	CRFK	2.9 ± 1.2	–	↓ viral replication	2006	[106]
HFQ	F–CoV	CRFK	>4	–	Weak effect	2006	[106]
CQ	FIPV	fcwf-4	–	–	↓ viral replication	2013	[110]
CQ	PHEV	Neuro-2a	–	–	↓ viral replication	2017	[111]

CQ: Chloroquine; CQ-MP: Chloroquine monophosphate; CQ-DP: Chloroquine diphosphate; AMD: Amodiaquine; HCQ: Hydroxychloroquine; FQ: Ferroquine; HFQ: Hydroxy ferroquine; SARS-CoV: Sever acute respiratory syndrome-coronavirus; MERS-CoV: Middle East respiratory syndrome-coronavirus; SARS-CoV-2: Sever acute respiratory syndrome-coronavirus 2; MHV4: Mouse hepatitis virus Type 4; F–CoV: Feline coronavirus; FIPV: Feline infectious peritonitis virus; PHEV: Porcine hemagglutinating encephalomyelitis virus; Vero cells: African green monkey kidney epithelial cells; Huh7 cells: Human hepatocyte-derived carcinoma cells; L132: human epithelial lung cells; HRT-18: Human ileocecal colorectal adenocarcinoma cells; MΦ: macrophages; CRFK cells: Crandell–Reese feline kidney cells; fcwf-4 cells: Felis catuswhole fetus-4 cells; Neuro-2a: murine neuroblastoma cells; EC₅₀: 50% Effective concentration; SI: Selectivity index defined as the ratio of drug efficacy to cytotoxicity.

^aTested at different multiplicities of infections (MOIs) of 0.01–0.8.