Isolated essential oils as antifungal compounds for organic materials

Abstract

Organic industrial materials are exposed to fungal deterioration; to prevent this, several additives can be used. In the present work, Egyptian cotton linters, linen textile, and parchment (goat skin) provided from industrial zones in Egypt were used. The application of eco-friendly essential oils (EOs) isolated from Pinus rigida wood and Origanum majorana green leaves to cotton linter paper pulp (CLP), linen textile, and parchment as bio-fungicides to protect against the growth of Aspergillus terreus, Aspergillus flavus, and Aspergillus niger was evaluated using the fungal growth inhibition (FGI) assay and examined under SEM to show the extent of fungal infestation. By gas chromatography-mass spectrometry (GC–MS) analysis, the abundant compounds in P. rigida EO were determined to be 2-methylisoborneol (29.52%), and 4-isopropyl-5-methylhex-2-yne-1,4-diol (16.53%); in O. majorana EO, they were determined to be cis-β-terpineol (15.4%), terpinen-4-ol (14.39%), oleic acid (10.75%), and D-limonene (8.49%). CLP treated at a level of 500 μL/L with O. majorana EO showed a higher FGI against A. niger (47.66%), while P. rigida EO showed a higher FGI against A. flavus (74%) and A. terreus (100%). Parchment treated with 500 μL/L of O. majorana EO showed an FGI of 49% against the growth of A. niger, while P. rigida EO treated at a level of 500 μL/L showed FGIs of 78% and 100% against A. flavus and A. terreus, respectively. Linen textile treated with O. majorana EO at a level of 500 μL/L showed a higher FGI (49%) against A. niger, while P. rigida EO showed a higher activity against A. flavus (FGI 77.3%) and A. terreus (FGI 100%). The examined SEM images of materials treated with the EOs confirmed how these EOs suppressed or prevented the growth of molds compared with the control treatments. The findings indicate that the EOs from P. rigida and O. majorana considerably enhanced the performance of CLP, linen textile, and parchment materials; therefore, they can be recommended as promising antifungal agents with which to extend the shelf-life of these materials. This study shows the high effectiveness of the addition of natural oils that contain bioactive compounds to natural raw materials (CLP, linen textile, and parchment) in protecting against the growth of fungi. Subsequently, it is possible to protect these raw materials from deterioration and damage and prolong their lives as long as possible while maintaining the natural and mechanical specifications of the raw materials, especially in atmospheric conditions with a high humidity.