title: In vitro antiaggregation and deaggregation potential of Rhizophora mucronata and its bioactive compound (+)- catechin against Alzheimer's beta amyloid peptide (25-35).
abstract: OBJECTIVE
  Amyloid hypothesis states that endogenous β-amyloid peptides (Aβ), especially its aggregated oligomers and fibrils are the key pathogenic factors leading to Alzheimer's disease (AD). Therefore, inhibition of Aβ fibrillation rather than blocking its production is considered promising therapeutic intervention. Hence, the present study was carried out to assess the effect of methanolic leaf extract of R. mucronata (MERM) and its bioactive compound catechin on in vitro fibrillation of Aβ (25-35).
  
  
  METHODS
  Antiaggregation and disaggregation effect by MERM and (+)- catechin against Aβ (25-35) were assessed in three different phases by thioflavin T (ThT) fluorescence assay and confocal microscopic analysis. The conformational changes in the aggregated Aβ fibrils in the presence and absence of MERM and catechin were analysed by Fourier transform infrared (FTIR), transmission electron microscopy (TEM) and CD spectroscopy.
  
  
  RESULTS
  Results of ThT and confocal microscopic studies showed decrease in fluorescence intensity in MERM and catechin-treated groups illustrating that both MERM and catechin effectively inhibited fibril aggregation as well as destabilized preformed Aβ fibril. TEM revealed that MERM incubated samples were virtually devoid of structured fibrils but had an amorphous-like consistency, whereas the control contained structured fibrils of various width and length. FTIR analysis showed decrease in absorbance at 1630 cm-1(amide I region) in MERM-treated groups substantiating the results of ThT assay. Circular dichroism data indicate that catechin prevents the formation of β-structured aggregates of Aβ peptide.
  
  
  CONCLUSIONS
  Results suggest that MERM and catechin might have direct interaction with Aβ peptide preventing its fibrillation.
authors: a Department of Biotechnology , Alagappa University , Karaikudi , India.
authors: Natarajan
authors: N
authors: Suganthy
authors: a Department of Biotechnology , Alagappa University , Karaikudi , India.
authors: Dicson
authors: D
authors: Sheeja Malar
authors: a Department of Biotechnology , Alagappa University , Karaikudi , India.
authors: Kasi
authors: K
authors: Pandima Devi
mesh_terms: D016229:Amyloid beta-Peptides / Q000187:drug effects* / Q000378:metabolism / Q000494:pharmacology*; D002392:Catechin / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005702:Galantamine / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D018613:Microscopy, Confocal; D010446:Peptide Fragments / Q000187:drug effects* / Q000378:metabolism / Q000494:pharmacology*; D066329:Protein Aggregates / Q000187:drug effects*; D059748:Proteolysis / Q000187:drug effects*; D043982:Rhizophoraceae / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; D066329:Protein Aggregates; C000604414:amyloid beta-protein (23-35); D005702:Galantamine; D002392:Catechin
keywords: FTIR; Rhizophora mucronata; Thioflavin T fluorescence; catechin; circular dichroism spectroscopy; confocal microscopy; transmission electron microscopy