Synergistic antioxidant and antibacterial effects of a Zn-ascorbate metal–organic framework loaded with marjoram essential oil†

Antimicrobial resistance (AMR) has become an immense threat to public health leading to an urgent need for development of new technologies to tackle such a challenge. Plant-based drugs, specifically essential oils (EOs) and plant extracts, have shown significant potential as effective green antimicrobial agents. However, they suffer from high volatility and low thermal stability resulting in their inefficient utilization in commercial settings. Among the various nanoencapsulation technologies reported, metal–organic frameworks (MOFs) have been recently investigated as potential nanocarriers of EOs in attempt to enhance their stability. Herein, we report the utilization of Zn-ascorbate MOF for the encapsulation of marjoram essential oil (MEO) with synergistic antioxidant and antibacterial activities. The prepared composite was thoroughly characterized via a number of techniques and its antibacterial performance was investigated against various strains of Gram-negative and Gram-positive bacteria. The results demonstrated that the antioxidant activity originated from the ascorbic acid ligand (L-Asc), while the antibacterial activity originated from Zn²⁺ ions as well as encapsulated MEO.