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

Abstract

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

Graphical Abstract

Keywords:

• Aggregation
• amyloid
• inhibition
• herbal
• brahmi

Acknowledgements

SK and NV thank Gujarat Forensic Sciences University, Gandhinagar for providing the infrastructure and experimental facilities that made this work possible. VKR gratefully acknowledges the SASTRA deemed to be University Thanjavur, Tamilnadu, for providing necessary facility. VKR also acknowledge Prof. A. K. Sood, Department of Physics, IISc Bangalore, Karnataka, India, for providing AFM facility. SK also thank Dr. Prasenjit Maity, Associate Professor IRD, GFSU, for valuable discussion and Ms. Smita for proofreading and improving the manuscript.

Declaration statement

The authors declare no conflict of interest.

Additional information

Funding

SK gratefully acknowledges the support from the Gujarat Council on Science and Technology, Department of Science and Technology Government of Gujarat for Research grant (GUJCOST/MRP/2016-17/637). Senior research fellowship (SRF) from University Grant Commission (UGC) Govt. of India to NV is duly acknowledged.