Bacopa monnieri inhibit hen egg white lysozyme fibrillation and help in retaining its activity at acidic condition

Inhibiting protein misfolding and aggregation is crucial for the treatment of several amyloidoses. Though various types of synthetic drugs are being explored as therapeutic agents, herbal extracts are better alternative owing to their natural origin, higher bioavailability and improved biosafety characteristics. In the present study, we demonstrate that night long (∼12 hr) preincubation of hen egg white lysozyme (HEWL) with Bacopa monnieri (brahmi) at neutral pH, impede the aggregation and fibrillation of protein at pH 2.0. Employing different biophysical techniques such as static and dynamic light scattering, Thioflavin T (ThT) assay, sedimentation assay and atomic force microscopy (AFM), we show that brahmi inhibit the HEWL aggregation in concentration dependent manner. 8-anilino-1-naphthalene sulfonate (ANS) fluorescence reveals that brahmi masks the exposure of hydrophobic domain of lysozyme. Significant recovery of enzymatic activity of HEWL in the presence of brahmi at pH 2.0 is salient feature of this work. Nearly 90% recovery of catalytic activity of lysozyme after 216 hr (9 days) of incubation indicate that interaction of HEWL-brahmi stabilizes the native structure of protein thus enhancing the activation energy barrier for protein misfolding and subsequent aggregation. Our findings show that brahmi could be promising alternative for the therapies of several protein misfolding disorders.Communicated by Ramaswamy H. Sarma.