Impact Of Electromagnetic Induction Heating On Antimicrobial Capacity Of Hydro-Distilled Leaves Of Pelargonium Graveolens

In this work, the usefulness of electromagnetic induction heating assisted hydrodistillation was investigated for Pelargonium graveolens leaves as a natural source of high value agents. In vitro antimicrobial activity of the extracts was evaluated against six bacterial strains and two fungal strains respectively using disc diffusion and Liquid Macrodilution methods. A comparative study on quantitative aspects over extraction time proves that conventional hydrodistillation (C-HD) gives an identical extraction kinetic behavior to electromagnetic induction heating assisted hydrodistillation (HD-EMI) with high extraction rates recorded when using HD-EMI. This latter increases the EOs yield for both fresh and dried leaves to (0.41 ± 0.04) % and (0.64 ± 0.03) % respectively versus (0.117± 0.04) % and (0.35± 0.02) % using C-HD. Compared to conventional heating, electromagnetic induction treatments result in 50 % lower extraction time and HD-EMI essential oils show an improved antibacterial activity. Against Escherichia coli and Staphylococcus aureus, HD-EMI and C-HD EOs show minimal inhibition concentrations (MICs) of 0.17 mg.ml-1 and 0.34 mg.ml-1, respectively. Their MICs reach 0.34 mg.ml-1 and 0.68 mg.ml-1 against Klebsiella pneumoniae and Pseudomonas aerogenosa. The inhibition of Candidas albicans and Rhizopus arrhizus cannot occur at MIC values below 0.68 mg.ml-1. Electromagnetic induction heating is thus a green and effective method for extracting high-value antibacterial compounds from Pelargonium graveolens leaves. Using the DPPH test, Pelargonium leaf EOs show antioxidant activity close to that of gallic acid, further demonstrating its potential as a promising source of preservatives in the food industry.