Lavandula pedunculata (Mill.) Cav. Aqueous Extract Antibacterial Activity Improved by the Addition of Salvia rosmarinus Spenn., Salvia lavandulifolia Vahl and Origanum compactum Benth

Salima Boutahiri; Bruno Eto; Mohamed Bouhrim; Hamza Mechchate; Asmaa Saleh; Omkulthom Al Kamaly; Aziz Drioiche; Firdaous Remok; Jennifer Samaillie; Christel Neut; Bernard Gressier; Ferdinand Kouoh Elombo; Laila Nassiri; Touriya Zair; Sevser Sahpaz

doi:10.3390/life12030328

Lavandula pedunculata (Mill.) Cav. Aqueous Extract Antibacterial Activity Improved by the Addition of Salvia rosmarinus Spenn., Salvia lavandulifolia Vahl and Origanum compactum Benth

Life (Basel). 2022 Feb 22;12(3):328. doi: 10.3390/life12030328.

Authors

Affiliations

¹ Univ. Lille, University of Liège, University of Picardie Jules Verne, JUNIA, UMRT 1158 BioEcoAgro, Specialized Metabolites of Plant Origin, F-59000 Lille, France.
² Research Team of Chemistry of Bioactive Molecules and the Environment, Laboratory of Innovative Materials and Biotechnology of Natural Resources, Faculty of Sciences, Moulay Ismaïl University, B.P. 11201 Zitoune, Meknes 50070, Morocco.
³ Laboratoires TBC, Laboratory of Pharmacology, Pharmacokinetics and Clinical Pharmacy, Faculty of Pharmacy, University of Lille, 3, Rue du Professeur Laguesse, B.P. 83, F-59000 Lille, France.
⁴ Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland.
⁵ Department of Pharmaceutical Sciences, College of Pharmacy, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia.
⁶ U1286 INFINITE Inst Translat Res Inflammat, University of Lille, Inserm, CHU Lille, F-59000 Lille, France.
⁷ Laboratory of Pharmacology, Pharmacokinetics and Clinical Pharmacy, Faculty of Pharmacy, University of Lille, 3, rue du Professeur Laguesse, B.P. 83, F-59000 Lille, France.
⁸ Research Team of Environment and Valorization of Plant and Microbial Resources, Faculty of Sciences, Moulay Ismaïl University, Meknes, B.P. 11201 Zitoune, Meknes 50070, Morocco.

Abstract

Lavender aqueous extracts are widely used in the Moroccan traditional medicine for their antibacterial properties. However, previous research have generally focused on investigating the antibacterial activity of lavender essential oils. The aim of this study is to evaluate the antibacterial activity of the Moroccan Lavandula pedunculata (Mill.) Cav. aqueous extract, alone, as well as in combination with extracts of other plant species known for their antibacterial activity: Salvia rosmarinus Spenn., Salvia lavandulifolia Vahl. and Origanum compactum Benth. We have tested the antibacterial activity of L. pedunculata, S. rosmarinus, S. lavandulifolia and O. compactum aqueous extracts individually and in combination against 34 strains using the agar dilution method. The combination effect was evaluated using the fractional inhibitory concentration (FIC). Polyphenol and tannin contents were determined using Folin-Ciocalteu reagent, and then some phenolic compounds were identified using UHPLC-MS. All the extracts displayed a large spectrum of antibacterial activity, especially against staphylococci, streptococci, Mycobacterium smegmatis and Proteus mirabilis. The minimum inhibitory concentration (MIC) values reached 0.15 ± 0.00 mg/mL for Staphylococcus warneri tested with S. lavandulifolia and 0.20 ± 0.07 mg/mL for Staphylococcus epidermidis tested with L. pedunculata or S. rosmarinus. Association of the L. pedunculata extract with S. rosmarinus, S. lavandulifolia and O. compactum showed synergistic effects (FIC ≤ 1). Moreover, the association of L. pedunculata with S. lavandulifolia was active against most of the Gram-negative strains resistant to the individual extracts. Determination of polyphenol and tannin contents showed the richness of the studied plants in these compounds. Additionally, chromatographic analysis demonstrated the high presence of rosmarinic acid in all the studied plant extracts. To our knowledge, this is the first study that shows the enhancing effect of the antibacterial activity of L. pedunculata aqueous extract combined with S. rosmarinus, S. lavandulifolia and O. compactum. These results confirm the effectiveness of the plant mixtures commonly used by traditional healers in Morocco and suggest that L. pedunculata might be used as an antibacterial agent either alone or, more efficiently, in combination with S. rosmarinus, S. lavandulifolia and O. compactum.

Keywords: Lavandula pedunculata (Mill.) Cav.; Origanum compactum Benth.; Salvia lavandulifolia Vahl.; Salvia rosmarinus Spenn.; antibacterial activity; polyphenols.