<i>In vitro</i> antiaggregation and deaggregation potential of <i>Rhizophora mucronata</i> and its bioactive compound (+)- catechin against Alzheimer’s beta amyloid peptide (25–35)

<p><b>Objective:</b> Amyloid hypothesis states that endogenous <i>β</i>-amyloid peptides (A<i>β</i>), especially its aggregated oligomers and fibrils are the key pathogenic factors leading to Alzheimer’s disease (AD). Therefore, inhibition of A<i>β</i> 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 <i>R. mucronata</i> (MERM) and its bioactive compound catechin on <i>in vitro</i> fibrillation of A<i>β</i> (25–35).</p> <p><b>Methodology:</b> Antiaggregation and disaggregation effect by MERM and (+)- catechin against A<i>β</i> (25–35) were assessed in three different phases by thioflavin T (ThT) fluorescence assay and confocal microscopic analysis. The conformational changes in the aggregated A<i>β</i> fibrils in the presence and absence of MERM and catechin were analysed by Fourier transform infrared (FTIR), transmission electron microscopy (TEM) and CD spectroscopy.</p> <p><b>Results:</b> 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 A<i>β</i> 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 <i>β</i>-structured aggregates of A<i>β</i> peptide.</p> <p><b>Conclusion:</b> Results suggest that MERM and catechin might have direct interaction with A<i>β</i> peptide preventing its fibrillation.</p

Scavenging effect of Seaweeds extract (100 μg/ml) and Standard BHT (50–250 μg/ml) on Nitric Oxide radical

<p><b>Copyright information:</b></p><p>Taken from "Bioprotective properties of seaweeds: evaluation of antioxidant activity and antimicrobial activity against food borne bacteria in relation to polyphenolic content"</p><p>http://www.biomedcentral.com/1472-6882/8/38</p><p>BMC Complementary and Alternative Medicine 2008;8():38-38.</p><p>Published online 10 Jul 2008</p><p>PMCID:PMC2475528.</p><p></p

Butyrylcholinesterase inhibitory activity of the active compounds (10–50 μg/ml).

<p>The result of BuChE inhibitory activity clearly shows that among the different treatment groups, alpha-bisabolol alone treatment possessed a maximum BuChE inhibitory activity(66%), with the IC50 value <10 μg/ml and showed significant inhibition (*p<0.1) at 50 μg/ml. Further, standard drug donepezil (IC50 value <6 μg/ml) and the compound of our interest, alpha-bisabolol displayed a significant inhibition on BuChE. Values are expressed as Mean ± SD (n = 3).</p

LC-MS/MS profile of ACTPG showing the presence of bioactive compounds.

<p>LC-MS/MS profile of ACTPG showing the presence of bioactive compounds.</p

Total antioxidant power of methanolic extract of seaweeds(100 μg/ml) in comparison with L-Ascorbic acid (2–10 μg/ml) measured by FRAP assay

<p><b>Copyright information:</b></p><p>Taken from "Bioprotective properties of seaweeds: evaluation of antioxidant activity and antimicrobial activity against food borne bacteria in relation to polyphenolic content"</p><p>http://www.biomedcentral.com/1472-6882/8/38</p><p>BMC Complementary and Alternative Medicine 2008;8():38-38.</p><p>Published online 10 Jul 2008</p><p>PMCID:PMC2475528.</p><p></p

Effects of ACTPG on antiaggregation and disaggregation property of Aβ _25–35.

<p>Analysis of the deposited amyloid aggregates as assessed by Confocal Laser Microscope System (CLSM FV300, Olympus, Tokyo, Japan) in (A) Phase I (20, 48 h) & (B) Phase II (96 h & 9days) and processed by Adobe Photoshop (Adobe Systems, Mountain View, CA, USA). The fluorescence intensity was visualized in each of three random fields of the sample. Confocal microscopic image represents a view of deposited Aβ _25–35 amyloid aggregates, with representative fibrils from Aβ _25–35 samples (control) and Aβ _25–35 samples incubated with the presence and absence of ACTPG and galantamine.</p

Reducing Ability of different seaweed extract and Standard BHT (50–250 μg/ml)

<p><b>Copyright information:</b></p><p>Taken from "Bioprotective properties of seaweeds: evaluation of antioxidant activity and antimicrobial activity against food borne bacteria in relation to polyphenolic content"</p><p>http://www.biomedcentral.com/1472-6882/8/38</p><p>BMC Complementary and Alternative Medicine 2008;8():38-38.</p><p>Published online 10 Jul 2008</p><p>PMCID:PMC2475528.</p><p></p

AChE inhibitory activity of the column fractions (F1-F18).

<p>The eluted fractions (F1-F18) were subjected to AChE inhibitory assay. Among the fractions, F10 (EA: MET-9:1) showed highest inhibitory activity (93%) against AChE, but similar when compared to positive control donepezil (97%). Values are expressed as Mean ± SD (n = 3).</p

LC-MS/MS spectrum of active fraction (F10) of ACTPG.

<p>LC-MS/MS spectrum of active F10 fraction of ACTPG showed the presence of essential oil alpha-bisabolol.</p

Bioactivity guided fractionation of ACTPG.

<p>Bioactive fractions were eluted with linear gradient of solvent with increasing polarity from n-hexane to water and the 18 fractions (F1-F18) were collected and subjected to cholinesterase inhibition assay.</p