Despite the growing scientific interest in finding effective treatment, SARS-CoV-2 virus remains a global major health burden and public health emergency. SARS-CoV main protease (Mpro) also known as chymotrypsin-like protease (3CLpro) is an important protein identified to be vital for SARS-CoV-2 survival. However, to date, there are no clinically approved drugs or antibodies specific for SARS-CoV-2. In the present study, we evaluated the interaction of 3CLpro with azadirachtin-A a bioactive compound from Azadiracta indica using in silico molecular docking study. Our results revealed that Azadiractin A docked well into the binding cavity of 3CLproSARS-CoV-2 with binding affinities ranges between -6.3 and -5.20 kcal/mol, and Pkd of 5.82~6.10 for the ten best binding modes. Azadiractin interacted with the active site of 3CLpro-SARS-CoV-2 by 2 conventional hydrogen bonding to HIS163 and GLU166, C-H interactions with HIS127, and alkyl interaction with PRO168 of the 3CLpro-SARS-CoV-2. We also found that the Azadiractin-A_3CLpro-SARS-CoV-2 complex is stabilized by various Vander wall forces with ASN142, LEU141, PHE140, MET165, GLN189, LEU167, THR190, and ALA191. In conclusion, our results suggested that Azadirachtin-A could be a potential inhibitor of SARS-CoV-2 main protease, thus worthy of further preclinical study.

Khaya senegalensis (Desr.) A. Juss. is a valuable medicinal plant with various pharmacological and therapeutic properties. Khaya senegalensis has been reportedly used in treating patients with urinary infections, diarrhea, and inflammation. It also has been used for the treatment of liver and kidney diseases. The chemical studies of the plant have revealed that various parts of the plant contain alkaloids, carbohydrates, proteins and amino acids, saponins, glycosides, quinones, flavonoids, terpenoids, etc. Various studies have shown that Khaya senegalensis plays a role in the prevention of cardiovascular disease, lowering blood glucose and serum lipid, decreasing blood pressure and strengthening the heart. This herb has anti-bacterial, anti-malaria, anti-fungal and anti-inflammatory effects. The present review, therefore, revealed that Khaya senegalensis is an important medicinal plant due to its traditional uses for the treatment of several diseases and the presence of many important bioactive compounds which have been implicated in the various pharmacological properties of the plant. Further experimental studies are needed to fully validate the medicinal properties.

Background: Malaria is a life-threatening disease caused by the protozoan parasite, Plasmodium. The emergence of drug-resistant Plasmodium species to currently available antimalarials has necessitated the search for more effective drugs. This study evaluated the antimalarial potential of the crude extract and fractions of Psidium guajava leaf in Plasmodium berghei infected mice. Method: Mice infected with Plasmodium berghei (P. berghei) were administered orally with the crude extract and fractions at doses ranging from 100-500 and 50-200mg/kg/day respectively, for five consecutive days. Results: The crude extract significantly (p<0.05) inhibited parasite growth as well as prevented body weight loss and packed cell volume reduction dose-dependently. Among the fractions, aqueous fraction was the most active with 54.26% inhibition of parasite growth at 200mg/kg. Remarkable inhibition of parasite growth by the crude extract and aqueous fraction was evident in the prolongation of mice survival relative to the control (27.33±1.76, 24.67±0.67, 28.0±1.16 and 8.33±0.67 for crude extract (500mg/kg), aqueous fraction (200mg/kg), chloroquine and negative control groups respectively). Phytochemical screening of the crude extract revealed the presence of phenol, alkaloids, flavonoids, and terpenoids. Conclusion: The results indicate that crude extract and aqueous fraction of P. guajava leaf are potent antimalarial agent that can be employed in the development of antimalarial drugs.