Screening and Evaluation of Cytotoxicity and Antiviral Effects of Secondary Metabolites from Water  Extracts of Bersama abyssinica against SARS-CoV-2 Delta

Background: Bersama abyssinica is widely distributed herb in Africa with varying medicinal uses in different countries. In Tanzania, the plant is famous for treatment of respiratory diseases including tuberculosis, tonsillitis, bronchitis, asthma and recently used for treatment Covid-19 symptoms. B. abyssinica is rich in several groups of active compounds including, phenolic acids, coumarins, flavonoids and tannins with potential pharmacological activities. Due to their broad medicinal uses, the water extract of leaf and stem bark has been registered as herbal medicine known as ‘Coviba Dawa’ for the treatment of viral and bacterial respiratory infections. Objective: The aim of this study was to extract active compounds from B.abyssinica , and analyse them for their effectiveness against Corona virus (SARS-CoV-2), the Delta variant obtained from Basel University thas is reported to be highly virulent. Methods: Bersama abyssinica stembark and leaves were air dried, sequentially extracted in various solvent on increase of polarity to yield extracts and fractions. The extracts were tested for presence of several metabolites and antioxidant activity. The most active water extract was analyzed by LC-MS/MC for identification of active compounds and all extracts were shipped to Basel university for anti SARS-CoV-2 Delta B1screening and antiproliferation assay. Results: The LC-MS/MS analysis of B. abyssinica water extract reveled the presence of four phenolic compounds namely; 2,4-di-tert-butylphenol, 4-formyl-2-methoxyphenyl propionate; 7,8-Dihydroxy-4-methylcoumarin and 2,3, 6-trimethoxyflavone. These compounds were revealed to have antioxidant activity and futher invitro analysis against SARS-CoV-2 Delta B1 revealed the antiviral activity against coronavirus. Conclusion: This study revealed a wide variety of active metabolites in B. abyssinica water extract with high antioxidant and antiviral activity which points out at B. abyssinica as a potential source of effective anti viral agents including anti SARS Cov2. We recommend further pre-clinical and clinical evaluation of B. abyssinica metabolites as potential antiviral and antibacterial agents.