Postharvest and Agroprocessing Research Centre, Department of Botany and Plant Biotechnology, University of Johannesburg, P.O. Box 524, Auckland Park, Johannesburg, 2006, South Africa.
South African Research Chairs Initiative in Sustainable Preservation and Agroprocessing Research, Department of Botany and Plant Biotechnology, University of Johannesburg, Johannesburg, 2006, South Africa.
Sci Rep. 2024 Aug 5;14(1):18071. doi: 10.1038/s41598-024-68979-3.
Significant postharvest losses and food safety issues persist in many developing nations, primarily due to fungal activities, including mycotoxin production. In this study, green synthesised zinc oxide nanoparticles (ZnO-NPs) were prepared from leaf extracts of Syzygium cordatum (ZnO 1), Lippia javanica (ZnO 2), Bidens pilosa (ZnO 3), and Ximenia caffra (ZnO 4). Physicochemical characteristics of the ZnO-NPs were determined using X-ray diffraction (XRD), Fourier transmission Infrared spectroscopy and ultraviolet-visible (UV-vis) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The XRD analysis confirmed the presence of a wurtzite crystal structure in the hexagonal shape of the ZnO nanoparticles (NPs), with an average size ranging between 25 and 43 nm. The microscopic examination of the morphology revealed the presence of spherical particles with sizes ranging from 37 to 47 nm in diameter. The antifungal efficacy of the ZnO-NPs was assessed against pathogenic plant fungi, including Botrytis sp. (STEU 7866), Penicillium sp. (STEU 7865), and Pilidiella granati (STEU 7864), using the poisoned food technique. Further antifungal evaluation of the ZnOPs was performed using the broth microdilution assay. A significant interaction between the type of ZnO-NPs and fungal species was observed, with the highest susceptibility in Mucor sp. to ZnO 2, achieving over 50% inhibition. Penicillium sp. also showed high susceptibility to all ZnO-NPs. Molecular docking results confirmed the strong H-bonding interactions of ZnO-NPs with fungal receptors in Mucor sp. and Penicillium sp., Botrytis sp. and P. granati exhibited the least susceptibility. Further tests revealed that ZnO 2 exhibited the highest inhibitory effect on Botrytis sp., with a low minimum inhibitory concentration (MIC) of 25 µg/mL, attributed to its larger positive zeta potential. This study indicates that ZnO NPs, particularly those mediated using Lippia javanica (ZnO 2), have promising potential as effective antifungal agents, which could play a significant role in reducing postharvest decay and losses.
在许多发展中国家，由于真菌活动，包括霉菌毒素的产生，仍然存在显著的产后损失和食品安全问题。在这项研究中，从 Syzygium cordatum（ZnO1）、Lippia javanica（ZnO2）、Bidens pilosa（ZnO3）和 Ximenia caffra（ZnO4）的叶提取物中制备了绿色合成的氧化锌纳米粒子（ZnO-NPs）。使用 X 射线衍射（XRD）、傅里叶变换红外光谱和紫外可见（UV-vis）光谱、扫描电子显微镜（SEM）和透射电子显微镜（TEM）来确定 ZnO-NPs 的物理化学性质。XRD 分析证实了 ZnO 纳米粒子（NPs）具有六方晶型的纤锌矿晶体结构，平均粒径在 25 至 43nm 之间。形态学的微观检查显示出存在直径为 37 至 47nm 的球形颗粒。使用毒饵法评估了 ZnO-NPs 对包括 Botrytis sp.（STEU 7866）、Penicillium sp.（STEU 7865）和 Pilidiella granati（STEU 7864）在内的致病性植物真菌的抑菌效果。使用肉汤微量稀释法进一步评估了 ZnOPs 的抑菌效果。观察到 ZnO-NPs 与真菌种类之间存在显著的相互作用，Mucor sp. 对 ZnO2 的敏感性最高，抑制率超过 50%。Penicillium sp. 对所有 ZnO-NPs 也表现出高度的敏感性。分子对接结果证实了 ZnO-NPs 与 Mucor sp. 和 Penicillium sp. 中的真菌受体之间的强氢键相互作用，Botrytis sp. 和 P. granati 的敏感性最低。进一步的测试表明，ZnO2 对 Botrytis sp. 的抑制作用最强，最低抑菌浓度（MIC）为 25µg/mL，这归因于其较大的正zeta 电位。这项研究表明，氧化锌纳米粒子，特别是使用 Lippia javanica（ZnO2）介导的纳米粒子，具有作为有效抗真菌剂的巨大潜力，这可能在减少产后腐烂和损失方面发挥重要作用。
