Java plum (Syzygium Cumini) leaves as a potential inhibitor of SARS-CoV-2 3-Chymotrypsine-Like Protease (3CLpro)

The 3-Chymotrypsine-Like Protease (3CLpro) is an enzyme that has a major function in the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) life cycle. It can be utilized as a protein target in search for new medications. Herbal plants are expected to have major contributions to the prevention and treatment of the 2019 Corona Virus Disease (COVID-19), as many herbal plants might have a strong affinity for 3CLpro in the treatment of COVID-19. The purpose of this study is to examine the inhibitory activity, pytochemical components, and antioxidant of extracts from nine herbal plants extracted by the Ultrasound Assisted Extraction (UAE) method that have the potential to inhibit recombinant SARS-CoV-2 3CLpro using an in vitro method as a result, it can be used to find novel medication candidates for COVID-19 therapy. Determining antioxidant activity using DPPH and ABTS method, total polyphenol and total flavonoid content using Folin Ciocalteu and quercetin method. From nine herbal plants tested, Java Plum leaves (Syzygium cumini) had the most active inhibitory activity with an inhibitory value of 3CLpro (IC₅₀ = 226 μg/ml) with a total polyphenol 413±1.83 mg GAE/g extract and total flavonoid as 12.091±0.037 mg QE/g extract. Measurement of antioxidant activity with the DPPH obtained an IC₅₀ value of 3.751 ± 0.0149 μg/ml, and with an ABTS gives IC₅₀ value 4.43±0.06 μg/ml. This suggests that Java Plum leaves could be a potential source of anti-COVID.