Table 1.

Summary of food supplements and their major functional effects.

Serial number	Food supplements	Properties	Status of the clinical trial
1	Zinc (Zn) (Antiviral)	◾Protects against oxidative stress and inhibit TNF-α, IFN-γ, FasR and JAK-STAT signaling pathways. ◾Modulates the viral entry, fusion, replication, viral protein translation and virus budding of respiratory viruses.	Phase 1 and 2
2	Vitamin D (VD) (Immune-boosting anti-inflammatory)	◾Blocks NF-κB p65 activation via up-regulation of I-kappa-B-alpha (IKB-α). ◾Decreases the expression of the pro-inflammatory type 1 cytokines: IL-12, IL-16, IL-8, TNF-α and IFN-γ and increases type 2 cytokines IL-4, IL-5, IL-10. ◾Upregulates the levels of antioxidant NRF-2, facilitates balanced mitochondrial functions.	Phase 2
3	Vitamin C (VC) (Immune-boosting, antioxidant)	◾Decreases pro-inflammatory cytokines, TNF-α and IFN-γ and increases anti-inflammatory IL-10 production. ◾Reduces the duration and severity of upper respiratory infections (viral infections). ◾Scavenges ROS, prevents lipid peroxidation, and protein alkylation and thus protect cells from oxidative stress induced cellular damage.	Phase 2
4	Curcumin (Immune-boosting, antiviral, anti-inflammatory, and antioxidant)	◾Stimulates host interferon production to activate the host innate immunity. ◾Binds to S protein at RBD and ACE2 receptor and inhibits virus entry. ◾Inhibits NF-κB, cyclinD1, COX-2, TNF-α, and STAT signaling pathways. ◾Neutralizes free radicals and enhances the production of antioxidant enzymes.	Phase 1 and 2
5	Cinnamaldehyde (Anti-inflammatory)	◾Suppress the NF-κB, TLR4, and NLRP3 signaling pathways. ◾Downregulates the production of prostaglandins.	Phase 2
6	Allicin (Antiviral, anti-inflammatory)	◾Downregulates the proinflammatory cytokines and inhibits the nitric oxide synthase expression in macrophages. ◾Possess antiviral effect on broad spectrum of viruses of HSV family, parainfluenza virus and human rhinovirus.	Phase 1 and 2
7	Piperine (Anti-inflammatory and antioxidant)	◾Reduces the production of the IL-1β, IL-6, TNF-α, COX-2, nitric oxide synthase-2, and NF-κB. ◾Neutralizes free radicals, ROS, and hydroxyl radicals.	Phase 2
8	Selenium (Immune-boosting, and antioxidant)	◾Promotes the T cell proliferation, NK cell activity and innate cell function. ◾It downregulates the proinflammatory cytokines (IL-1β and IL-6). ◾Augments glutathione peroxidase and other antioxidant selenoenzymes activities.	Phase 2
9	Propolis (Immune-boosting, anti-inflammatory)	◾Exhibits the immunomodulatory effect through extracellular signal-regulated kinase 2 and MAPK pathways and by modulating the NFAT and NF-κB activation. ◾Inhibits various viruses such as dengue virus type 2, herpes simplex virus, human cytomegalovirus, influenza virus A1.
10	Probiotics (Immune boosting, anti-inflammatory)	◾Lactobacillus plantarum DR7 suppress proinflammatory cytokines TNF-α, IFN-γ, enhances anti-inflammatory cytokines IL-10, IL-4. ◾Lactobacillus acidophilus CMCC878 reduces the bacterial load and inflammation in mice lungs infected with staphylococcus and pseudomonas. ◾Leuconostoc mesenteroides 32-77:1, L. plantarum 2,362, L. paracasei ssp. paracasei 19, Pediococcus pentosaceus 5-33:3 along with resistant starch, inulin etc reduce systemic inflammatory response syndrome and other infections. ◾Bifidobacterium longum BB536 prevents infection from influenza and improves innate immunity.	Phase 2
11	Lactoferrin (antiviral)	◾Downregulates the IL-6, TNF-α, and ferritin. ◾Inhibits the viral entry and suppress the viral replication.	Phase 1 and 2
12	Quercetin (antiviral)	◾Inhibits the production of the TNF-α, IL-8, IL-1α, COX, and LOX enzymes. ◾Possesses antiviral effects against both RNA (influenza and coronavirus) and DNA viruses (herpesvirus). ◾Act as ligand for the S protein of virus and ACE 2 and interferes in binding of virus to cells.	Phase 1 and 2