Biogenic Synthesis of MnO2 Nanoparticles With Leaf Extract of Viola betonicifolia for Enhanced Antioxidant, Antimicrobial, Cytotoxic, and Biocompatible Applications

Haibin Lu; Xueyang Zhang; Shakeel Ahmad Khan; Wenqiang Li; Lei Wan

doi:10.3389/fmicb.2021.761084

Biogenic Synthesis of MnO₂ Nanoparticles With Leaf Extract of Viola betonicifolia for Enhanced Antioxidant, Antimicrobial, Cytotoxic, and Biocompatible Applications

Front Microbiol. 2021 Nov 1:12:761084. doi: 10.3389/fmicb.2021.761084. eCollection 2021.

Authors

Haibin Lu^{1

2}, Xueyang Zhang^{1

2}, Shakeel Ahmad Khan³, Wenqiang Li⁴, Lei Wan²

Affiliations

¹ Shunde Hospital, Southern Medical University (The First People's Hospital of Shunde), Foshan, China.
² Stomatological Hospital, Southern Medical University, Guangzhou, China.
³ Center of Super-Diamond and Advanced Films (COSDAF), Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong.
⁴ Engineering Technology Research Centre for Sports Assistive Devices of Guangdong, Guangzhou Sport University, Guangzhou, China.

Abstract

In this study, we propose to synthesize NPs using plant extract containing active biomedical components, with the goal of obtaining NPs that inherit the biomedical activities of the plant. Herein, we report the synthesis of manganese dioxide nanoparticles (VBLE-MnO₂ NPs) using the leaves extract of Viola betonicifolia, in which the biological active plant's secondary metabolites function as both reducing and capping agents. The synthesized NPs were successfully characterized with different spectroscopic techniques. The antibacterial, antifungal, and biofilm inhibition properties of the synthesized VBLE-MnO₂ NPs were further explored against a variety of bacteria (Gram-positive and Gram-negative) and mycological species. Additionally, their antioxidant ability against linoleic acid peroxidation inhibition, cytobiocompatibility with hMSC cells, and cytotoxicity against MCF-7 cells were investigated compared to leaves extract and chemically synthesized manganese dioxide NPs (CH-MnO₂ NPs). The results were demonstrated that the synthesized VBLE-MnO₂ NPs presented excellent antibacterial, antifungal, and biofilm inhibition performance against all the tested microbial species compared to plant leaves extract and CH-MnO₂ NPs. Moreover, they also exhibited significant antioxidant potential, which was comparable to the external standard (ascorbic acid); however, it was higher than plant leaves extract and CH-MnO₂ NPs. Furthermore, the synthesized CH-MnO₂ NPs displayed good cytobiocompatibility with hMSC cells compared to CH-MnO₂ NPs. The enhanced antioxidant, antibacterial, antifungal, and biofilm inhibition efficacy as compared to CH-MnO₂ NPs might be attributed to the synergistic effect of the VBLE-MnO₂ NPs' physical properties and the adsorbed biologically active phytomolecules from the leaves extract of V. betonicifolia on their surface. Thus, our study establishes a novel ecologically acceptable route for nanomaterials' fabrication with increased and/or extra medicinal functions derived from their herbal origins.

Keywords: MnO2 NPs; antimicrobial; antioxidant; biofilm inhibition; cytotoxic.