This study explores the therapeutic potential of three proaporphine alkaloids-cissamaline, cissamanine, and cissamdine, which were recently isolated from Cissampelos capensis L.f., against Parkinson's disease (PD). Using computational techniques, we investigated their efficacy as inhibitors of a key protein in PD. ADMET analysis demonstrated that these alkaloids conform to the Lipinski, Pfizer, Golden Triangle, and GSK rules, indicating favorable safety, oral bioavailability, and a high probability of passing the human intestinal and blood-brain barriers. They were neither substrates nor inhibitors of any CYP enzymes tested, indicating minimal metabolic interference and an enhanced safety profile. Molecular docking studies revealed binding energies of -9.05 kcal/mol (cissamaline), -9.95 kcal/mol (cissamanine), and -10.65 kcal/mol (cissamdine) against MAO-B, a critical PD target, surpassing the control (zonisamide, -6.96 kcal/mol). The molecular interaction analyses were also promising, with interactions comparable to the control. Molecular dynamics (MD) simulations confirmed stable protein-ligand interactions, with root-mean-square deviation (RMSD) values ranging from 1.03 Å to 3.92 Å, root-mean-square fluctuation (RMSF) values remaining below 1.14 Å, and radius of gyration (RGyr) values between 20.20 Å and 20.50 Å, indicating compact structures. Hydrogen bonding analysis revealed maximum hydrogen bond counts of 6 (cissamanine), 5 (cissamaline), and 4 (cissamdine), demonstrating robust interactions with MAO-B. Density Functional Theory (DFT) calculations revealed the highest electrophilicity (ω =0.151), highest electron affinity (EA =0.075), and smallest HOMO-LUMO gap (ΔE =0.130) for cissamanine, indicating enhanced reactivity. These results advocate for further in vitro and in vivo studies to evaluate the compounds' potential as PD therapeutics.
Breast cancer remains a significant challenge in oncology, highlighting the need for alternative therapeutic strategies that target necroptosis to overcome resistance to conventional therapies. Recent investigations into natural compounds have identified 8,12-dimethoxysanguinarine (SG-A) from Eomecon chionantha as a potential necroptosis inducer. This study presents the first computational exploration of SG-A interactions with key necroptotic proteins-RIPK1, RIPK3, and MLKL-through molecular docking, molecular dynamics (MD), density functional theory (DFT), and molecular electrostatic potential (MEP) analyses. Molecular docking revealed that SG-A exhibited a stronger affinity for MLKL (-9.40 kcal/mol) compared to the co-crystallized ligand (-6.29 kcal/mol), while its affinity for RIPK1 (-6.37 kcal/mol) and RIPK3 (-7.01 kcal/mol) was lower. MD simulations further demonstrated the stability of SG-A within the MLKL site, with RMSD values stabilizing between 1.4 and 3.3 Å over 300 ns, indicating a consistent interaction pattern. RMSF analysis indicated the preservation of protein backbone flexibility, with average fluctuations under 1.7 Å. The radius of gyration (Rg) results indicated a consistent value of ~15.3 Å across systems, confirming the role of SG-A in maintaining protein integrity. Notably, SG-A maintains two critical H-bonds within the active site of MLKL, reinforcing the stability of the interaction. Principal component analysis (PCA) indicated a significant reduction in MLKL's conformational space upon SG-A binding, implying enhanced stabilization. Dynamic cross-correlation map (DCCM) analysis further revealed that SG-A induced highly correlated motions, reducing internal fluctuations within MLKL compared to the co-crystallized ligand. MM-PBSA revealed the enhanced binding efficacy of SG-A, with a significant binding free energy of -31.03 ± 0.16 kcal/mol against MLKL, surpassing that of the control (23.96 ± 0.11 kcal/mol). In addition, the individual residue contribution analysis highlighted key interactions, with ARG149 showing a significant contribution (-176.24 kcal/mol) in the MLKL-SG-A complex. DFT and MEP studies corroborated these findings, revealing that the electronic structure of SG-A is conducive to stable binding interactions, characterized by a narrow band gap (~0.16 units) and distinct electrostatic potential favourable for necroptosis induction. In conclusion, SG-A has emerged as a compelling inducer of necroptosis for breast cancer therapy, warranting further experimental validation to fully realize its therapeutic potential.