A Practical Perspective on the Use of Botanicals During the COVID-19 Pandemic: From Proven to Potential Interactions

In this review, we examined the top 10 nutraceutical products sold in Italian pharmacies and parapharmacies as well as hypermarkets and supermarkets; in the first, three product categories saw the greatest increase in sales (vitamins and minerals, immunostimulants, and sleep products) for the 12-month period between October 2019 and October 2020 (including first pandemic wave of SARS-CoV-2). We are investigating their respective formulas and isolating the botanicals that are used to make them. Many of these products have undergone preclinical and clinical studies. We performed a systematic literature search in the MEDLINE database using PubMed and Google Scholar from November 15, 2020 to December 15, 2020 (including studies carried out between 1980 and 2020). The search terms that were used included the complete name of the medicinal plant in English or Latin and the terms "cytochrome" or "drug interactions," crossing, respectively, the Latin name and English common names with "cytochrome" and "drug interactions." The search included in vitro and in vivo studies describing the effects of interaction between the plant (extract or botanical medicine) and human cytochromes. Despite their great complexity, there is decidedly limited clinical data on botanical medicine. In fact, of the 28 botanicals that were examined, only 2 (Citrus paradisi and Rhodiola rosea) show in vivo pharmacological interactions in human subjects. On the contrary, for the other botanicals, there is only weak evidence of dubious clinical significance or potential interactions shown in animal models or in vitro without clinical confirmation. This study provides a rational assessment of the most widely used products, including those used in self-medication, to simplify patient management during the COVID-19 health emergency.