Table 3.
Natural Product Candidates Could Be Used against SARS-CoV-2.
| Compound | Mechanisms | Reference |
|---|---|---|
| Natural products affect SARS-CoV | ||
| Tryptanthrin | RdRp and PLP2 inhibitor Moderates the viral RNA genome synthesis and progeny virus production |
83 |
| Myricetin | Interacts with ATP/ADP binding pocket of Hel protein Interacts with critical residues of the ATPase domain (N265, Y269, and R443) |
84 |
| Scutellarin, baicalin | Conjugate with chemokines and interfere with their capacity to activate cellular receptors CCR5 and CXCR4 | 78 |
| Glycyrrhizin | Induces nitrous oxide synthase, which inhibits virus replication | 78, 85, 86 |
| Aloe emodin, hesperetin sinigrin |
Inhibit cleavage activity of the 3CLpro | 83 |
| Lycorine | Unclear how this compound interacts with expressed viral proteins and antigens | 76 |
| Amentoflavone | SARS-CoV 3CL protease inhibitor | 58 |
| Sugar N-acetyl glucosamine and agglutinins |
Bind to the ACE2 receptor, resulting in the inhibition of SARS-CoV fusion with the target cell | 79 |
| Preparation Echinaforce | Interacts directly with viral envelope proteins | 87 |
| Natural agents affect IL-6 | ||
| Tocilizumab | Inhibits the binding of IL-6 to its receptor | 88 |
| Epigallocatechin-3-gallate | Blocks IL-6 synthesis in IL-1, inhibits p38 pathways, inhibits IL-6–induced apoptosis | 88 |
| Curcumin | Inhibits the production of pro-inflammatory cytokines and reduces IL-6/IL-6-soluble receptor (sIL-6R)-induced STAT3 and ERK phosphorylation | 89 |
| Celastrol | Reduces levels of IL-6 and IL-1β by inhibition of STAT3 phosphorylation to block the IL-6 receptor signaling pathway | 90 |
| Statins | Inhibits the enzyme HMG-CoA reductase and JAK/STAT3 signaling pathway for IL-6-mediated inflammation | 91 |
| Bisphosphonate | Inhibits the enzyme FPP synthase and the JAK/STAT3 signaling pathway for IL-6-mediated inflammation; reduces sIL-6R serum levels | |
| Polyphenolic compounds | Hinder JAK/STAT3 signaling pathway for IL-6-mediated inflammation | |
| Genistein | Decreases IL-6 production | |
| Sophoricoside | Arrests IL-6 bioactivity | |
| Isoflavones | Inhibit production of IL-6 | |
| Eriodictyol | Inhibits expression of inflammatory cytokines TNF-α, IL-6, and IL-1β | 92 |
| Luteolin | Reduces TNF-α, KC, ICAM-1, and SOD; activates MAPK and NF-κB | |
| Quercetin | Diminishes TNF-α, IL1-β, IL-5, and IL-6; NO and COX-2 | |
| Kaempferol | Reduces inflammatory cells; activates MAPK and NF-κB pathways | |
| Mitraphylline | Lowers IL-1α, IL-1β, IL-17, TNF-α, IL-6, and IL-8 | |
| Asperuloside | Depletes TNF-α, IL-1β, and IL-6 levels | |
| Callicarpa japonica | Reduces cytokine IL-6 | |
| Sakuranetin | Minimizes eosinophils, TNF-α, IL-5, IL-1β, M-CSF, and RANTES; inhibits NF-κB in lung, MMP-9-positive, and MMP-12-positive cells; increases TIMP-1 expression | |
| Apigenin | Inhibits eosinophil infiltration in lung tissue and IL-6 | |
| Herbal formula PM014 | Lowers IL-6 levels | |
| Punica granatum | Depletes eosinophils and cytokines IL-1β and IL-5 | |
| Peganum harmale | Inhibits the production of both IL-6 and TNF-α | 93 |
| Baicalin | Decreases the induction of IL-1, IL-6, TNF-α, and IFN-γ | |
| Kaempferia parviflora | Lowers phosphorylation of STAT3, Akt, and the expression of Mcl-1 in response to exogenous IL-6 stimulation | 94 |