Phytochemical Analysis and Antimicrobial Activity of Ziziphus spina-christi and Tamarix aphylla Leaves' Extracts as Effective Treatment for Coronavirus Disease 2019 (COVID-19)

Background: The increased use of antibiotics has led to the frequent occurrence of resistant bacterial strains᾽ infections and increased side effects. It is inevitable that medicinal plants and their good antimicrobial activities for controlling and curing different infectious diseases is always a salient feature of various investigations. Also, understanding the plant species in the light of the Holy Quran, religious texts, and the sacred books could make a useful contribution to studying two significant plants used as ancient and reliable medicines. Objectives: The present research used two plants for medicinal products to evaluate their antimicrobial activity. Ziziphus spina-christi (sider) is a medicinal and traditional plant and ethanol and methanol extracts of its leaves have been used against some bacterial and viral infections. Another herbal remedy is Tamarix aphylla with the local name of Ghaz, as the largest known species of Tamarix. The stem smoke of Tamarix aphylla is used by people in the desert area as an antibiotic and antimicrobial agent. Methods: The leaves of Ziziphus spina-christi and Tamarix aphylla were collected to extract their flavonoids and alkaloids using methanol and ethanol, respectively. Moreover, in the process of extraction, powdered and dried leaves by using disc diffusion testing and undiluted neat solution were prepared. Results: The extracted phytochemicals exhibited antimicrobial activity of the two plants through alkaloids and flavonoids as secondary metabolites. Substantial influences on impairing the energy metabolism weakened microbial growth, resulting in the fat formation and protein inhibition. Conclusions: It was concluded that flavonoids and alkaloids from Ziziphus spina-christi and Tamarix aphylla leaves have antimicrobial potential. On the other hand, the process of cell division can be affected by alkaloids that are bound to DNA. Also, flavonoids bind to DNA and RNA, resulting in impairing energy metabolism causing the weakened growth of the microbe affecting protein inhibition and fat formation. Viral cell walls are made up of proteins. Coronavirus spike proteins and viral membrane fusions are wonderful molecules. Through binding to the host cell surface receptor, coronaviruses enter host cells and then fuse the host and viral membranes. Through precipitating the protein components, tannins in Ziziphus spina-christi behave as detoxifying agents by inhibiting their growth.