A review on antibacterial and therapeutic plasma-enhanced activities of natural extracts

Emerging traditional drug-multiresistant bacteria has become a critical health problem worldwide, which has motivated the development of alternative therapies and technologies to combat infections associated with such bacteria. The application of antibacterial and non-cytotoxic natural extracts combined with the therapeutic use of cold plasma offers alternatives to antibiotics and conventional therapies. Thus, the present review aims to show that research of the synergistic effect of plasma treatment on the antibacterial and therapeutic properties of natural extracts (e.g., Rosmarinus officinalis, Citrus sinensis, Azadirachta indica, Rhizome Atractylodes macrocephala) is a relatively new field with few reports, but with promising published results. The cited publications were recovered from scientific databases such as Google Scholar, SpringerLink, Wiley, and Elsevier - ScienceDirect through an extensive search. In this concern, it is reported that a more significant reduction of the bacterial population in wet samples (e.g., food material, cell cultures, broths, tissues) and polymer fabrics (e.g., polyethene terephthalate, cellulose) could be achieved by using cold plasma treatments combined with natural extracts rather than use them separately. Simultaneously, it is reported that the use of cold plasma and natural extracts enhances cell growth and attachment under in vitro and in vivo conditions. It was found that atmospheric-pressure plasma jet devices, instead of the dielectric barrier discharge ones, have primarily been used to improve the antibacterial activity of polymer fabrics and in wound healing therapies. Thus, some promising results on the antibacterial and non-cytotoxic properties of plasma-enhanced natural extracts have been reported, but more research (especially comparative studies) is needed to determine their therapeutically safe use. (C) 2021 The Authors. Published by Elsevier B.V. on behalf of King Saud University.