First-described recently discovered non-toxic vegetal-derived furocoumarin preclinical efficacy against SARS-CoV-2: a promising antiviral herbal drug.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the aetiology of coronavirus disease 2019 (COVID19) pandemic. ICEP4 purified compound (ICEP4) is a recently discovered furocoumarin-related purified compound derived from the roots and seeds of Angelica archangelica (herbal drug). ICEP4-related herbal preparations have been extensively used as active herbal ingredients in traditional medicine treatments in several European countries. Extraction method of patent pending ICEP4 (patent application no. GB2017123.7) has previously shown strong manufacturing robustness, long-lasting stability, and repeated chemical consistency. Here we show that ICEP4 presents a significant in vitro cytoprotective effect in highly virulent-SARS-CoV-2 challenged Vero E6 cellular cultures, using doses of 34.5 and 69 M. No dose-related ICEP4 toxicity was observed in Vero E6 cells, M0 macrophages, B, CD4+ T and CD8+ T lymphocytes, Natural Killer (NK) or Natural Killer T (NKT) cells. No dose-related ICEP4 inflammatory response was observed in M0 macrophages quantified by IL6 and TNF release in cell supernatant. No decrease in survival rate was observed after either 24 hr acute or 21-day chronic exposure in in vivo toxicity studies performed in C. elegans. Therefore, ICEP4 toxicological profile has demonstrated marked differences compared to others vegetal furocoumarins. Successful ICEP4 doses against SARS-CoV-2-challenged cells are within the maximum threshold of toxicity concern (TTC) of furocoumarins as herbal preparation, stated by European Medicines Agency (EMA). The characteristic chemical compounding of ICEP4, along with its safe TTC, allow us to assume that the first-observation of a natural antiviral compound has occurred. The potential druggability of a new synthetic ICEP4-related compound remains to be elucidated. However, well-established historical use of ICEP4-related compounds as herbal preparations may point towards an already-safe, widely extended remedy, which may be ready-to-go for large-scale clinical trials under the EMA emergency regulatory pathway. To the best of the authors knowledge, ICEP4-related herbal drug can be postulated as a promising therapeutic treatment for COVID19.