Optimization, characterization and biosafety of oregano, rosemary and mint oil mixture against Penicillium digitatum in citrus using L-optimal mixture design.
Rahaf Khaled, Sara Mohamed, Amira Mohamed, Aya Khairy, Hesham Elhariry, Ashraf Bakry, Neima K Elsenosy, Naglaa Ebeed, Salem S Salem, Thanaa ElNoby, Samah H Abu-Hussien
Author Information
Rahaf Khaled: Biotechnology Program, New Programs Administration, Faculty of Agriculture, Ain Shams University, P.O. Box 68, Cairo, 11241, Egypt.
Sara Mohamed: Biotechnology Program, New Programs Administration, Faculty of Agriculture, Ain Shams University, P.O. Box 68, Cairo, 11241, Egypt.
Amira Mohamed: Biotechnology Program, New Programs Administration, Faculty of Agriculture, Ain Shams University, P.O. Box 68, Cairo, 11241, Egypt.
Aya Khairy: Biotechnology Program, New Programs Administration, Faculty of Agriculture, Ain Shams University, P.O. Box 68, Cairo, 11241, Egypt.
Hesham Elhariry: Department of Food Science, Faculty of Agriculture, Ain Shams University, P.O. Box 68, Cairo, 11241, Egypt.
Ashraf Bakry: Department of Genetics, Faculty of Agriculture, Ain Shams University, P.O. Box 68, Cairo, 11241, Egypt.
Neima K Elsenosy: Department of Genetics, Faculty of Agriculture, Ain Shams University, P.O. Box 68, Cairo, 11241, Egypt.
Naglaa Ebeed: Department of Genetics, Faculty of Agriculture, Ain Shams University, P.O. Box 68, Cairo, 11241, Egypt.
Salem S Salem: Department of Botany and Microbiology, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt.
Thanaa ElNoby: Department of Agricultural Economics, Faculty of Agriculture, Ain Shams University, P.O. Box 68, Cairo, 11241, Egypt.
Samah H Abu-Hussien: Department of Agricultural Microbiology, Faculty of Agriculture, Ain Shams University, P.O. Box 68, Cairo, 11241, Egypt. samah_hashem1@agr.asu.edu.eg. ORCID
The increasing demand for natural alternatives to synthetic fungicides has prompted research into natural products like essential oils for postharvest disease management. This study investigated the antifungal, antioxidant, cytotoxic, and genotoxic potential of essential oil mixtures derived from oregano, rosemary, and mint against Penicillium digitatum, the predominant fungal pathogen causing green mold in orange fruits. P. digitatum NPAGRASU 2024 was isolated and identified as the most abundant species (60.2%) from infected oranges. It was deposited in GenBank with gene accession number PP930644 and deposited in MIRCEN culture collection as EMCC 358874. The antimicrobial activity of individual essential oils was evaluated, with oregano exhibiting the highest antifungal activity (inhibition zone diameter of 4.2 cm) against P. digitatum. L-optimal mixture design of response surface methodology (RSM) optimization revealed a highly effective mixture (Run 8) comprising 46.26% oregano and 53.74% rosemary, with a 99.65% actual growth reduction. The oregano oil demonstrated potent antioxidant activity, reaching approximately 75% DPPH radical scavenging at 3.125 mg/mL. Cytotoxicity assessment using the MTT assay showed morphological changes and reduced cell viability in liver cells treated with the PEOs mixture at 300 µg/mL. However, the optimized mixture did not induce significant chromosomal aberrations compared to the control, suggesting minimal genotoxic effects. In vivo, evaluation on oranges revealed 60% inhibition of green mold by the 1% (v/v) optimized mixture for 7 days. Histological analysis indicated low toxicity to the liver at the highest tested concentration (1% mixture). GC-MS analysis identified major compounds like cavarcol, caryophyllene, eucalyptol, phenols and levomenthol in oregano oil, contributing to its bioactivities. This study demonstrates the potential of optimized essential oil mixtures as effective and eco-friendly alternatives for postharvest disease control.
