Preprint / Version 1

Validation of Broth Macrodilution Volatilization Method for Testing of Essential Oils in Liquid and Vapor Phase: Chemical Composition, Cytotoxicity, and Antibacterial Effect of Indian Medicinal Plants against Pneumonia-Causing Pathogens

Authors

  • Aishwarya Chaure Department of Crop Sciences and Agroforestry, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, 16500 Prague, Czech Republic; [email protected] (A.C.); [email protected] (M.H.); [email protected] (J.A.)
  • Marketa Houdkova Department of Crop Sciences and Agroforestry, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, 16500 Prague, Czech Republic; [email protected] (A.C.); [email protected] (M.H.); [email protected] (J.A.)
  • Julien Antih Department of Crop Sciences and Agroforestry, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, 16500 Prague, Czech Republic; [email protected] (A.C.); [email protected] (M.H.); [email protected] (J.A.)
  • Klara Urbanova Department of Sustainable Technologies, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, 16500 Prague, Czech Republic; [email protected]
  • Ivo Doskocil Department of Microbiology, Nutrition and Dietetics, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, 16500 Prague, Czech Republic; [email protected]
  • Mukund Naik National Center for Natural Resources, Pt. Ravishankar Shukla University, Raipur 492010, India; [email protected]
  • Khageshwar Patel Department of Applied Sciences, Amity University, Manth (Kharora), State Highway 9, Raipur 493225, India; [email protected]
  • Ladislav Kokoska Department of Crop Sciences and Agroforestry, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, 16500 Prague, Czech Republic; [email protected] (A.C.); [email protected] (M.H.); [email protected] (J.A.)

Keywords:

antimicrobial activity, Cymbopogon citratus, Cyperus scariosus, GC/MS, headspace analysis, macrodilution, MTT assay, respiratory infections, Trachyspermum ammi, vapor phase, volatiles

Abstract

Essential oils (EOs) have great potential in inhalation therapy for the treatment of respiratory infections. However, innovative methods for evaluation of antimicrobial activity of their vapors are still needed. The current study reports validation of the broth macrodilution volatilization method for assessment of the antibacterial properties of EOs and shows the growth-inhibitory effect of Indian medicinal plants against pneumonia-causing bacteria in liquid and vapor phase. Among all samples tested, Trachyspermum ammi EO exhibits the strongest antibacterial effect against Haemophilus influenzae, with minimum inhibitory concentrations of 128 and 256 µg/mL in the liquid and vapor phases, respectively. Furthermore, Cyperus scariosus EO is found to be nontoxic to normal lung fibroblasts assessed by modified thiazolyl blue tetrazolium bromide assay. Chemical analysis performed using gas chromatography–mass spectrometry identified α-citral, cyperotundone, and thymol as the main constituents of Cymbopogon citratus, C. scariosus, and T. ammi EOs, respectively. In addition, β-cymene is identified as the major compound of T. ammi EO vapors when analyzed using solid-phase microextraction and gas-tight syringe sampling techniques. This study demonstrates the validity of the broth macrodilution volatilization method for antimicrobial screening of volatile compounds in the vapor phase and suggests the therapeutic potential of Indian medicinal plants in inhalation therapy. Keywords: antimicrobial activity, Cymbopogon citratus, Cyperus scariosus, GC/MS, headspace analysis, macrodilution, MTT assay, respiratory infections, Trachyspermum ammi, vapor phase, volatiles

Author Biographies

Aishwarya Chaure, Department of Crop Sciences and Agroforestry, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, 16500 Prague, Czech Republic; [email protected] (A.C.); [email protected] (M.H.); [email protected] (J.A.)

Formal analysis, Investigation, Writing – original draft

Marketa Houdkova, Department of Crop Sciences and Agroforestry, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, 16500 Prague, Czech Republic; [email protected] (A.C.); [email protected] (M.H.); [email protected] (J.A.)

Writing – review & editing, Supervision

Julien Antih, Department of Crop Sciences and Agroforestry, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, 16500 Prague, Czech Republic; [email protected] (A.C.); [email protected] (M.H.); [email protected] (J.A.)

Writing – review & editing, Supervision

Klara Urbanova, Department of Sustainable Technologies, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, 16500 Prague, Czech Republic; [email protected]

Supervision

Ivo Doskocil, Department of Microbiology, Nutrition and Dietetics, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, 16500 Prague, Czech Republic; [email protected]

Investigation

Mukund Naik, National Center for Natural Resources, Pt. Ravishankar Shukla University, Raipur 492010, India; [email protected]

Supervision

Khageshwar Patel, Department of Applied Sciences, Amity University, Manth (Kharora), State Highway 9, Raipur 493225, India; [email protected]

Supervision

Ladislav Kokoska, Department of Crop Sciences and Agroforestry, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, 16500 Prague, Czech Republic; [email protected] (A.C.); [email protected] (M.H.); [email protected] (J.A.)

Conceptualization, Writing – review & editing, Supervision

Downloads