Carica papaya is a medicinal and fruit plant owing biological activities including antioxidant, antiviral, antibacterial and anticancer. The present study aims to investigate the acetyl (AChE) and butyryl (BChE) cholinesterase inhibitory potentials of C. papaya extracts as well as their chemical compositions. The chemical composition of the active extract was identified using a gas chromatography-mass spectrometry (GCMS). Ellman enzyme inhibition assay showed that the alkaloid-enriched leaf extract of C. papaya possessed significant anti-BChE activity with an enzyme inhibition of 75.9%. GC-MS analysis showed that the alkaloid extract composed mainly the carpaine (64.9%) – a major papaya alkaloid, and some minor constituents such as aliphatic hydrocarbons, terpenes and phenolics. Molecular docking of carpaine revealed that this molecule formed hydrogen bond and hydrophobic interactions with choline binding site and acyl pocket. This study provides some preliminary findings on the potential use of C. papaya leaf as an herbal supplement for the prevention and treatment of Alzheimer’s disease.

The new coronavirus disease (COVID-19) outbreak has challenged us to take unprecedented steps to bring this pandemic under control. In view of the urgency of this situation, convalescent plasma which was used in previous coronavirus outbreaks has emerged as one of the treatment options in this current pandemic. This is mainly due to the fact that convalescent plasma has been studied in a few case series with promising outcomes. In addition, on-going large clinical trials aimed to further evaluate the effectiveness, safety, and optimal dosage, duration and timing of administration of convalescent plasma are indeed revealing a certain level of promising results. Therefore, this article aims to provide an overview of possible mechanisms of actions of convalescent plasma, its benefits and its level of usage safeness by summarizing the existing evidence on the use of convalescent plasma in COVID-19 patients.