An Exploratory Review of Potential Adjunct Therapies for the Treatment of Coronavirus Infections

OBJECTIVE: The purpose of this exploratory review was to examine vitamin D, zinc, vitamin A, elderberry (Sambucus nigra), garlic (Allium sativum), licorice (Glycyrrhiza glabra), stinging nettle (Urtica dioica), N-acetylcysteine, quercetin, and selenium as potential adjunct therapies for the treatment of coronavirus infections. METHODS: A search of PubMed was performed for articles published from 2005 to 2021. Keywords searched were “zinc,” “vitamin A,” “vitamin D,” “Sambucus nigra,” “Allium sativum,” “Glycyrrhiza glabra,” “Urtica dioica,” “N-acetylcysteine,” “quercetin,” “selenium,” and “coronavirus.” RESULTS: There were 47 articles selected for this review. Findings included that vitamin D, zinc, vitamin A, S. nigra, A. sativum, G. glabra, U. dioica, N-acetylcysteine, quercetin, and selenium have been shown to produce antiinflammatory, immunostimulatory, or antiviral effects that may enhance the actions of standard therapeutics for the treatment of coronavirus infections. Specific to effects against COVID-19, we found research articles related to the effects of only vitamin D, zinc, G. glabra, quercetin, and selenium. CONCLUSION: We identified nonpharmaceutical supplements (vitamin D, zinc, vitamin A, S. nigra, A. sativum, G. glabra, and U. dioica) which may have potential to provide support for those with coronavirus infections. However, rigorous clinical studies need to be performed before any clinical recommendations can be made.