Screening and evaluation of cytotoxicity and antiviral effects of coviba dawa against SARS-CoV-2 Delta

ABSTRACT

Background: Bersama abyssinica is a common tree in Africa, with diverse medical uses in different areas. The plant is well-known in Tanzania for treating respiratory disorders such as TB, tonsillitis, bronchitis and asthma, The plant has lately been utilized for treatment of COVID-19 symptoms. Water extract of leaf and stem bark has been registered as a herbal medication known as 'Coviba Dawa' for the treatment of viral and bacterial respiratory infections due to its broad medical benefits. The aim of this work was to test for the cytotoxicity and antiviral effects of bioactive ingredients from B. abyssinica extracts against the Delta variant of the SARS-CoV-2 coronavirus. Method(s) Bersama abyssinica leaves and stem barks were dried under shade in room temperature and then pulverized to obtain small pieces before soaking into different solvents. One hundred grams of each, leaves and stem barks were extracted in petroleum ether, dichloromethane, ethyl acetate and ethanol. Water extract was obtained by decoction of 100g of stem bark into water. Phenols, flavonoids, tannins with antioxidant activity were confirmed as components of the extracts. Analysis of aqueous extracts of bark stem bark and leaves was done by LC-MS/MS (Q-orbitrap-Ultra High Performance Thermofisher Company). Antiviral screening and cytotoxicity experiments were conducted in a Biosafety Level 3 (BSL-3) Laboratory facility according to previously established Standard operating procedures (SOPs). Result(s) The existence of four phenolic compounds in B. abyssinica water extract;2,4-di-tert-butylphenol, 4-formyl-2-methoxyphenyl propionate, 7,8-Dihydroxy-4-methylcoumarin, and 2,3, 6-trimethoxyflavone with antioxidant activity was confirmed by LC-MS/MS analysis. In-vitro testing of the extracts revealed antiviral activity against coronavirus the delta B1 variant of SARS-CoV2. Conclusion(s) We recommend further studies to characterize the medicinal value of B. abyssinica metabolites as potential antiviral and antibacterial agents.