COMPUTATIONAL INSIGHTS INTO LEAF COMPOUNDS OF Pterocarpus santalinoides AGAINST FabH PROTEIN RECEPTOR

Diarrhea remains one of the most prevalent diseases in Nigeria, especially among children aged between 1 and 5. The death rate by diarrheal disease is about 1.5 million per year, which include 620 thousand children below the age of 5, and 320 thousand adults above the age of 70, Diarrheal disease has been ranked as the second leading cause of mortality of children. Ethno medical and scientific reports abound on using the extract from the leaf of Pterocarpus santalinoides for treatment of diarrhea of any kind. GCMS analysis was carried out to determine the bioactive compound present in the leaf extract responsible for the efficacy and result revealed the presence of 13 bioactive compounds with Oxiraneundecanoic acid, 3-pentyl-cis-methyl ester (37.89 %), Oleic Acid (35.49%) and 9-Octadecenoic acid (Z)-, methylester (12.35%) as the most abundant. The result indicated that the efficacy of the plant against diarrhea diseases could be linked to 9-Octadecenoic acid (Z)-, methylester found in the crude extract. The bioactive compounds from the extract were docked on the diarrhea protein crystal structure of beta-ketoacyl-acp synthase iii + malonyl-coa FabH (1HNJ) to know their binding affinities and compared with that of co-crystallize ligand and standard drug. The docking result showed that the cocrystallize ligand has the best binding affinity of -7.6 kcal/mol, followed by the phytocompound 9-Octadecenoic acid (Z)-, methylester (6.7 kcal/mol). 9,12-Octadecadienoic acid, methyl ester has affinity -6.3 kcal/mol, Aspidospermidin-17-ol and oleic acid have affinity ( -6.1 kcal/mol) while Hexadecanoic acid, 14-methyl-, methyl ester and phytol both have (- 6.0kcal/mol) respectively while Undec-10-ynoic acid, undecyl ester has affinity (-5.9kcal/mol). The result revealed that the co-crystallize ligand has the best affinity followed by all the phytocompounds from the extract while the commercial drug has less affinity but with a very good interaction. All the compounds from the extract have good binding affinities within the range of -6.7 – 4.9kcal/mol. The interaction results of the extracts with the disease protein proved the anti-diarrhea efficacy of the plant as acclaimed ethnomedically therefore validating its traditional use against diarrhea diseases.