  Citation: Mkaddem Mounira, G.; Ahlem, Z.; Abdallah Mariem, B.; Romdhane, M.; K. Okla, M.; Al-Hashimi, A.; Alwase, Y.A.; Madnay, M.M.; AbdElgayed, G.; Asard, H.; et al. Essential Oil Composition and Antioxidant and Antifungal Activities of Two Varieties of Ocimum basilicum L. (Lamiaceae) at Two Phenological Stages. Agronomy 2022, 12, 825. https://doi.org/ 10.3390/agronomy12040825 Academic Editor: Filomena Monica Vella Received: 1 February 2022 Accepted: 16 March 2022 Published: 28 March 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). agronomy Article Essential Oil Composition and Antioxidant and Antifungal Activities of Two Varieties of Ocimum basilicum L. (Lamiaceae) at Two Phenological Stages Guedri Mkaddem Mounira 1 , Zrig Ahlem 2, * , Ben Abdallah Mariem 1 , Mehrez Romdhane 1 , Mohammad K. Okla 3 , Abdulrahman Al-Hashimi 3 , Yasmeen A. Alwase 3 , Mahmoud M. Madnay 4 , Gehad AbdElgayed 5 , Han Asard 5 , Gerrit T. S. Beemster 5 and Hamada AbdElgawad 5, * 1 Energy, Water, Environment and Process Laboratory, (LR18ES35), National EngineeringSchool of Gabes, University of Gabes, Gabes 6072, Tunisia; mounira.mkaddem@gmail.com (G.M.M.); mariem.rom@yahoo.com (B.A.M.); mehrez.romdhane1965@gmail.com (M.R.) 2 Faculty of Sciences of Gabès-City Erriadh, Zrig, Gabes 6072, Tunisia 3 Botany and Microbiology Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia; malokia@ksu.edu.sa (M.K.O.); aalhashimi@ksu.edu.sa (A.A.-H.); yasmeen@ksu.edu.sa (Y.A.A.) 4 Department of Botany and Microbiology, Faculty of Science, Cairo University, Giza 12613, Egypt; madany@cu.edu.eg 5 Integrated Molecular Plant Physiology Research, Department of Biology, University of Antwerp, 2000 Antwerpen, Belgium; gehad@yahoo.com (G.A.); han.asard@uantwerpen.be (H.A.); ger-rit.beemster@uantwerpen.be (G.T.S.B.) * Correspondence: ahlem18zrig@yahoo.fr (Z.A.); hamada.abdelgawad@uantwerpen.be (H.A.) Abstract: Ocimum basilicum is a valuable source of bioactive metabolites with high preventive and ther- apeutic effectiveness. Here we aimed to investigate the effect of phenological stages (vegetative and flowering stages) on essential oil composition and biological activities of two varieties of O. basilicum (Fino Verde variety and Genovese varieties). To this end, the level of essential oils, flavonoids and phenols, as well as antioxidant and antifungal activities were measured. At the metabolic level, essential oil at vegetative stage of O. bailicum Fino Verde and Genovese variety was constituted by 22 and 26 compounds representing 71.68% and 82.54% of the total oil, respectively. Where germacrene D (10.07%), bicyclogermacrene (6.07%) and β-elemene (4.88%) were the most present components in Fino Verde variety. Moreover, 22.19% are oxygenated monoterpenes represented mainly by the linalool (15.18%) and 1.8 cineole (6.36%) in Genovese variety. The individuals of essential oils were significantly increased to 40 components in Fino Verde variety (98.01% of total essential oil) and decreased to 15 components (95.6% of total essential oil) in Genovese variety at flowering stage. At this stage, the oxygenated monoterpenes (78.4%) were the major fraction represented by linalool (40.1%) and 1.8 cineole (30.96%) in Fino Verde variety, however 64.69% were esters which mainly represented by the methyl cinnamate (64.69%), and 16.83% of oxygenated monoterpenes and Linalool (12.7%) were recorded for Genovese variety. Genovese variety showed the highest levels at both vegetative and flowering stage compared to Fino Verde variety. At flowering stage, the two varieties showed high antioxidant and antifungal activities. Overall, O. basilicum properties offer prospects for their use as a source, particularly at flowering stage to extend new medicines based on natural bioactive molecules. Keywords: Ocimum basilicum; genovese variety; fino verde variety; essential oil; vegetative stage flowering stage; antioxidant activity; antifungal activity 1. Introduction Basil (Ocimum basilicum L.) is an important essential oil crop, medicinal plant and culinary herb O. basilicum belongs to the Lamiaceae family [1,2], and grows in tropical and Agronomy 2022, 12, 825. https://doi.org/10.3390/agronomy12040825 https://www.mdpi.com/journal/agronomy