In silico screening of phytochemicals from Senna species against SARS-CoV-2 viral and host targets: Potential multi-target antiviral candidates

Phytochemicals found in plants play a key role in defense against pathogens, including viruses. They are studied as alternative or complementary treatments for emerging and re-emerging viral infections like COVID-19. Due to emerging new variants of the virus, COVID-19 continues to be a public health concern, highlighting the importance of scientific research. The new COVID-19 virus (SARS-CoV-2) is responsible for a serious respiratory illness that can vary in severity from being asymptomatic to severe, sometimes even leading to death. The aim of this investigation was to screen pharmacologically active phytochemicals from Senna plants for their potential efficacy against SARS-CoV-2 viral proteins and its entry cell receptor. In silico molecular docking approaches were used. Softwares, including Chimera, PyRx, Ligplot, BIOVIA Discovery Studio, CASTp and admetSAR were used in the study. Forty phytochemicals present in Senna sp. were screened. Promising among them were emodin, kaempferol-3-O-gentiobioside, rhein, emodin-8-O-beta-D-glucopyranoside, luteoline, astragalin (kaempferol-3-O-glucoside), sennoside A, B, C, D, sitosterol and daucosterol. These phytochemicals of the Senna sp. showed significant binding affinity to four viral proteins and one human target protein, including the RNA-dependent RNA polymerase (RdRP), spike (S) glycoprotein, Nsp10-Nsp16 complex, main protease (Mpro/CLpro) and the human angiotensin converting-enzyme 2 (ACE2). ADMET properties showed a minor toxicity profile of the promising anti-viral compounds. We conclude that some of the Senna phytochemicals have promising antiviral efficacy against COVID-19 and may work as a cocktail of pharmacologically effective phytochemicals against the virus. However, experimental studies are warranted for a tangible conclusion and designate a candidate drug.