Screening of guava (Psidium guajava) leaves extracts against β-hematin formation

Background: Malaria control is crucial as a result of the growing antimalarial drug- resistance not only in South-East Asia but also in Africa. Developing novel, safe, effective, and affordable drugs is a key to combat malaria. Medicinal plants and some fruits are intensive sources in the drug discovery effort to treat malaria. Objective: The main aim of the work is to investigate Guava ( Psidium guajava ) infused water and water-ethanol leaf extracts against β-hematin formation in-vitro . Methodology: To determine the identity of any possible active secondary metabolite in P. guajava leaves, a full scan LC-ESi-MS-PDA was run within a mass range of 100-1200 amu. Moreover, the in-vitro colorimetric semi-quantitative assays that are based on β-hematin inhibition and optical density measurement at 405nm were utilized. Results and discussion: The effect of using 35% ethanol in extracting guava leaves showed that concentrations between 1 and 0.4mg/ml have an activity superior to guava water extract and comparable to the positive control. Among the identified flavonoids glycosides are quercetin 3- O -glycoside, quercetin-galloylhexoside, morin-3- O -lyxoside, morin-3- O -arabinoside, quercein-3- O -arabinoside (guaijaverin) and ellagic acid. This indicates to an encouraging complexation with the free heme over β-hematin formation.