Two dimensional (2D) MXenes as an emerging class of materials for antimicrobial applications: properties and mechanisms

MXenes have gained significant importance in many applications in the fields of energy, environment and healthcare. The versatile features of MXenes enable them as a wonder material for their wide category of applications. Tunable surface chemistry and nano-dimensional layered features of MXenes are accounted for their improved multifunctional properties among the other two-dimensional materials. Of various applications, MXenes show the relevant properties toward antimicrobial disinfection of bacteria, fungi and viruses including the SARS responsible for COVID-19. Therefore, the development, characterizations and mechanism of MXenes-based materials are important to bring these advanced materials for their real-time antimicrobial applications. In this context, this review presents a glimpse of MXenes in terms of their synthesis processes, characterizations, antimicrobial properties, and elucidate their mechanism of actions toward antibacterial, antifungal and antiviral activities. Finally, it concludes with a future perspective of MXenes towards their biomedical applications.

Phenolic and flavonoid contents in Malva sylvestris and exploration of active drugs as antioxidant and anti-COVID19 by quantum chemical and molecular docking studies

The exploration of natural sources of antioxidant phytochemicals for human use with little toxicity gained worldwide attention. The preliminary screening of Malva sylvestrisextracts revealed that its phytochemicals such as polyphenols, flavonoids and tannins, have high therapeutic potential. The total phenolic/flavonoids compounds ofMalva sylvestris were extracted and isolated using bioassay guidelines, as well as in-silico studies. The extracts radical scavenging activity was further investigated using 1-diphenyl-2-picrylhydrazyl (DPPH) and nitric oxide (NO) radical bioassays. The antioxidant potentials of various fractions were compared to standard antioxidants such as ascorbic acid and quercetin. The dichloromethane extracts of Malva sylvestris exhibited the antiradical activity against DPPH and NO with radical scavenging activities (RSA) of 88.52 and 91.05 % with IC50 values 22.11 and 19.01 µg/mL respectively. Bio guided isolation form the dichloromethane sub fractions that afforded twelve phytochemicals. Furthermore, the frontier molecular orbitals (FMO), several molecular descriptors, electron affinity, ionization potential and molecular electrostatic potential (MEP) have been discussed to probe the active sites of various phytochemicals. A systematic study of isolated drugs wasconducted, as well as docking, frontier molecular orbitals energies, active sites and molecular descriptors were compared with drugs currently used against COVID19 namely, dexamethasone, hydroxychloroquine, favipiravir and remdesivir. For the first time, through molecular docking approach, the inhibitions of these plant phytochemicals with NADPH were recorded to show antioxidant behavior and to explore anti-SARS-CoV-2 using core protease (6LU7) protein.