Resumen: Inhibiting the main protease 3CLpro is the most common strategy in the search for antiviral drugs to fight the infection from SARS-CoV-2. We report that the natural compound eugenol is able to hamper in vitro the enzymatic activity of 3CLpro, the SARS-CoV-2 main protease, with an inhibition constant in the sub-micromolar range (Ki = 0.81 \u03bcM). Two phenylpropene analogs were also tested: the same effect was observed for estragole with a lower potency (Ki = 4.1 \u03bcM), whereas anethole was less active. The binding efficiency index of these compounds is remarkably favorable due also to their small molecular mass (MW < 165 Da). We envision that nanomolar inhibition of 3CLpro is widely accessible within the chemical space of simple natural compounds. Idioma: Inglés DOI: 10.3390/ph14090892 Año: 2021 Publicado en: Pharmaceuticals 14, 9 (2021), 892 [10 pp.] ISSN: 1424-8247 Factor impacto JCR: 5.215 (2021) Categ. JCR: PHARMACOLOGY & PHARMACY rank: 69 / 279 = 0.247 (2021) - Q1 - T1 Categ. JCR: CHEMISTRY, MEDICINAL rank: 16 / 63 = 0.254 (2021) - Q2 - T1 Factor impacto CITESCORE: 4.0 - Pharmacology, Toxicology and Pharmaceutics (Q2) - Biochemistry, Genetics and Molecular Biology (Q3)