Computational Elucidation of Putative Sperm-signalling Targets of Flueggea virosa: Network Pharmacology, Molecular Docking and Molecular Dynamics
Kehongo Moses Nyanguru
*
Department of Mathematics and Physical Sciences, Maasai Mara University, PO Box 861-20500, Narok, Kenya and Centre for Traditional Medicine and Drug Research, Kenya Medical Research Institute, P.O. Box 54840- 00200, Nairobi, Kenya.
Aloys Mosima Osano
Department of Mathematics and Physical Sciences, Maasai Mara University, PO Box 861-20500, Narok, Kenya.
Samwel Cheruiyot
Department of Mathematics and Physical Sciences, Maasai Mara University, PO Box 861-20500, Narok, Kenya.
Edwin Murungi
Department of Medical Biochemistry, Kisii University, P.O. Box 408 - 40200, Kisii, Kenya.
Elizabeth Kigondu
Centre for Traditional Medicine and Drug Research, Kenya Medical Research Institute, P.O. Box 54840- 00200, Nairobi, Kenya.
*Author to whom correspondence should be addressed.
Abstract
Background: The methanolic root-bark fraction of Flueggea virosa (KBLM) has previously been associated with impaired human sperm function, but the signalling proteins potentially linked to its putatively annotated constituents remain uncertain.
Aims: To identify putative sperm-signalling targets of constituents of the methanolic root-bark fraction of Flueggea virosa, previously shown to disrupt human sperm function.
Study Design: An LC-MS/MS-informed, hypothesis-generating computational study integrating network pharmacology and structure-based modelling.
Methodology: Putatively annotated KBLM constituents were subjected to protein-target prediction. Predicted targets were intersected with a sperm-associated protein dataset and analysed using protein-protein interaction networks and pathway mapping. Prioritised ligand–protein complexes were evaluated by molecular docking, 100-ns molecular dynamics simulations and MM-GBSA analysis.
Results: Target prediction identified 279 proteins, of which 168 overlapped with a sperm-associated dataset of 5,596 proteins. Network analysis highlighted calcium, cyclic-nucleotide and phosphorylation-related signalling pathways, with AKT1 showing the highest centrality. AKT1, EGFR, PTGS2 and SRC were prioritised for structure-based evaluation. Docking scores ranged from -10.488 to -7.253 kcal/mol; kaempferol 3-O-(4-O-galloyl)-β-D-glucopyranoside yielded the lowest score against AKT1. During 100-ns simulations, AKT1 and PTGS2 exhibited comparatively constrained protein trajectories, and catechin movement in the SRC complex broadly tracked the protein. Both EGFR trajectories showed pronounced conformational displacement, with protein Cα RMSD exceeding 10 Å. MM-GBSA analysis further prioritised the AKT1 complexes; the galloylated kaempferol glycoside yielded a late-window ΔGbind estimate of -118.18 ± 9.10 kcal/mol.
Conclusion: AKT1 and SRC emerged as experimentally tractable candidate targets, whereas EGFR and PTGS2 remained more provisional hypotheses. Chemical authentication and target-specific assays in human sperm are needed to validate these computational predictions.
Keywords: Flueggea virosa, human sperm, sperm signalling, AKT1, network pharmacology, molecular docking, molecular dynamics, non-hormonal contraception