TABLE 2.
List of the promising phytochemicals used worldwide for antiviral studies that could play a crucial role in the treatment of COVID-19.
| Source (medical plants) | Antiviral compound(s) | Virus | Mode of antiviral effects | References |
|---|---|---|---|---|
| Curcuma longa L., Camellia sinensis (L.) Kuntze, Mentha longifolia (L.) L., Phonix hanceana var. loureiroi, Capsicum annum L., and Olea europea L. | Glucoside, luteoloin-7, curcumin, de menthoxy curcumin, epicatechin- gallate, oleuropein, apigenin-7, and catechin | Coronavirus (CoV) | Mpro protein of COVID-19 was inhabited by all these antiviral compounds. However, further investigations are required. | Khaerunnisa et al. (2020) |
| Tylophora indica (Burm.f.) Mabb. | Tylophorine | CoV | These biomolecules showed broad-spectrum potential for inhibiting coronaviruses. | Yang et al. (2020) |
| Lycoris radiata (L'Hér.) Herb. | Lycorine | CoV | Lycorine could be a promising biomolecule for antiviral activity. | Suryanarayana and Banavath (2020) |
| Psoralea corylifolia (L.) Medik. | Bavachinin, corylifol, and psoralidin | CoV | The ethanol extract of these secondary metabolites showed potential activity against SARS-CoV PLpro. | Kim et al. (2014) |
| Clivia miniata (L.) Medik. | Mycophenolate mofetil and lycorine | HCov-OC43, MHV- A59, HCoV-NL63, and MERS-CoV | Mycophenolate mofetil demonstrated immune-suppressing effects on CoV, while lycorine showed inhibition of RNA, DNA, and protein synthesis that affects cell division. | Shen et al. (2019) |
| Carapichea ipecacuanha (Brot.) L. Andersson | Emetine | Emetine showed strong antiviral activity by blocking entry of MERS-CoV. | ||
| Aglaia foveolata Pannell | Silvestrol | HCoV-229E | Silvestrol demonstrated strong inhibition of cap-dependent viral mRNA translation. | Muller et al. (2018) |
| Broussonetia papyrifera (L.) L'Hér. ex Vent. | Kazinol A, Kazinol F, Kazinol B, Kazinol J | Papain-like and 3-chymotrypsin–like CoV cysteine proteases | These polyphenols showed inhibition against both CL and PL CoV proteases. | Park et al. (2017) |
| Broussonetia papyrifera (L.) L'Hér. ex Vent. | Polyphenols, for example, biphenyl propanoid and broussochalcone A and B | CoV cysteine proteases | All of these polyphenols could be potential biomolecules for developing anti-CoV drugs. | Park et al. (2017) |
| Peel extracts of Citrus sinensis L., Anthemis hyaline, and Nigella sativa L. | Essential oils | CoV-infected HeLa- epithelial carcinoembryonic antigen | Reduces the virus loads by downregulation of tryptophan- operon (TRP- gene) of CoV. | Ulasli et al. (2014) |
| Paulownia tomentosa (Thunb.) Steud. | Tomentin | SARS-CoV | These granulated flavonoids inhibit the proteases of SARS-CoV. | Cho et al. (2013) |
| Camellia sinensis (L.) Kuntze | Catechins | SARS-CoV | During screening of various teas, catechins showed strong inhibition for N-protein of SARS-CoV. | Roh (2012) |
| Aglaia perviridis Hiern | Myricetin and scutellarein | SARS-CoV | This study showed its effect against ATPase activity that leads to inhibition of the helicase protein of SARS-CoV. | Yu et al. (2012) |
| Pelargonium sidoides DC. | Extract EPs® 7630 | Human coronavirus (HCoV) | EPs® 7630 interferes with replication of various respiratory viruses such as HCoV. | Michaelis et al. (2011) |
| Eucalyptus globus | 1,8-cineol | SARS-CoV-2 | Translocation of NF-kB p65 to the nucleus is inhibited, which negatively affects NFkB-driven transcription. | Greiner et al. (2013) |
| Curcuma longa L. | Curcumin | SARS-CoV-2 | Curcumin showed inhibition of the Notch1-GATA3 signaling pathway and averted the progress of allergic inflammation. | Chong et al. (2014) |
| Papaver somniferum L. | Codeine | SARS-CoV-2 | Codeine is metabolized to morphine in the animal body. It produces an analgesic effect by interacting with muopoid receptors, which are available in the cells of the nervous system (central and peripheral). | Bhandari et al. (2011), Kodaira and Spector (1988) |
| Thebaine |