ABSTRACT
Covid-19 is caused by aetiological agent for SARS-CoV-2. The disease has caused pandemic responsible for deaths and economic loss worldwide. Therefore, novel drugs of covid-19 primarily using herbs are urgently needed. Cabya (Piper retrofractum Vahl.) is a popular spice and also traditionally applied for herbal medicines. This study conducted an in silico experiment to screen methanolic active compounds in cabya and test their inhibitory activities against main protease enzyme (Mpro) as receptor of SARS-CoV-2. The in silico approach complied with molecular docking protocols enabling to evaluate performance of the compounds to inhibit Mpro. Two common drugs were used as control, i.e. chloroquine and ivermectin. As the results, molecular docking showed a promising inhibition by active compounds in cabya;in this regard, beta-sitosterol demonstrated the strongest inhibition against Mpro with binding affinity -7,5 kcal/mol, which is better than chloroquine (-4.8 kcal/mol) and close to ivermectin (-8,5 kcal/mol). The interaction resulted from two hydrogen bonds with amino acids ARG A131 and ASP A289 at distance of 15Å and 2,49 Å, respectively. The inhibition site of beta-sitosterol was similar to that of ivermectin. This research revealed the potential use of cabya for covid-19 treatment through restriction of molecular binding between virus and receptor.