الاستخلاص الأخضر وتخليق الجسيمات النانوية من النباتات الطبية: تقييم أنشطتها البيولوجية متعددة الوظائف في المختبر وعن طريق المحاكاة الحاسوبية

Abstract

This study explores the green synthesis and characterization of zinc oxide nanoparticles (ZnO-NPs) using aqueous extracts from two medicinal plants, oregano (Origanum majorana) and cotula cinerea. All prepared nanoparticles were characterized using spectroscopic techniques: UV-Vis spectroscopy, FTIR spectroscopy, and X-ray diffraction (XRD). The multifunctional biological activities of these nanoparticles were evaluated through both in vitro experiments and computer simulations. In vitro tests demonstrated high antioxidant capacity, particularly for the cotula cinerea-derived zinc oxide nanoparticles, which achieved the highest DPPH free radical inhibition rate of 62.99%. Confirming these findings, computational evaluation using density functional theory (DFT) on zinc oxide (ZnO₆, ZnO₉, and ZnO₁₂) aggregate models revealed that increasing aggregate size enhances thermodynamic stability and chemical reactivity. Furthermore, analysis of the electronic properties showed that the HOMO-LUMO gap decreases with increasing aggregate size, explaining the efficient electron transport in the nanoparticles. These results underscore the potential of these biosynthesized particles in advanced chemical engineering applications, such as catalysis, water treatment, and the development of advanced sustainable materials.