Assessment of Mutagenic Effect of G. acerosa and S. wightii in S. typhimurium (TA 98, TA 100, and TA 1538 strains) and Evaluation of Their Cytotoxic and Genotoxic Effect in Human Mononuclear Cells: A Non-Clinical Study

The marine red algae (Gelidiella acerosa and Sargassum wightii) possessing excellent antioxidant and anticholinesterase activity were subjected to toxicity evaluation for a deeper understanding of other bioprotective properties of seaweeds. Cytotoxic evaluation was done by trypan blue exclusion, and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays using human PBMC (peripheral blood mononuclear cells) and RBC (red blood cells) lysis assay using human erythrocytes. Mutagenicity of the seaweeds was analyzed by Ames salmonella mutagenicity test with the histidine dependent mutant strains TA 98, TA100 and TA 1538. Genotoxic activity was verified in PBMC by comet assay. The results suggest that benzene extract of G. acerosa (BEGA) and dichloromethane extract of S. wightii (DMESW) did not show cytotoxic effect both in PBMC and erythrocytes. Evaluation of mutagenic activity suggests that the seaweeds did not cause any mutagenic effects both in the absence and the presence of S9 microsomal fraction in all the three Salmonella mutant strains. Results of genotoxic study showed that PBMC treated with seaweed extracts (1 mg/mL) exhibit less or no damage to cells, thus proving the non-genotoxic effect of the extract. Since these in vitro non-clinical studies clearly demonstrate the non-toxic nature of the seaweeds, they could be exploited for further characterization, which would result in development of novel and safe therapeutic entities

Gelidiella acerosa protects against Aβ 25–35-induced toxicity and memory impairment in Swiss Albino mice: an in vivo report

Context: Alzheimer’s disease (AD) is believed to develop due to deposition of β-amyloid (Aβ) peptide. Hence, efforts are being made to develop potent drug that target amyloid hypothesis. Objective: The present study explores the effect of the seaweed Gelidiella acerosa (Forsskål) Feldmann & Hamel (Gelidiellaceae) against Aβ 25–35 peptide in Swiss albino mice. Materials and methods: The animals were administered through intracerebroventricular (ICV) injection with the Aβ 25–35 peptide (10 μg/10 μL/ICV site) on 21st day of the pretreatment of G. acerosa (whole plant) benzene extract (200 and 400 mg/kg bw). On day 30, animals were sacrificed and brain tissue homogenate was prepared. The activities of AChE, BuChE, b-secretase, MAO-B, and caspase-3 were determined, and Bax expression was assessed by Western blotting. Results: Gelidiella acerosa benzene extract restored the level of antioxidant enzymes and prevented lipid and protein oxidation significantly (p < 0.05). The extract protected the mice from cholinergic deficit significantly (p < 0.05) by inhibiting the activities of AChE and BuChE, which was about 0.116 ± 0.0088 U/mg of protein and 0.011 ± 0.0014 U/mg of protein respectively, which was otherwise increased in peptide-treated group (0.155 ± 0.007 U/mg of protein and 0.015 ± 0.0012 U/mg of protein respectively). Interestingly, G. acerosa benzene extract inhibited β-secretase and MAO-B activity. Reduction (p < 0.05) in level of caspase-3 activity and Bax expression suggests that G. acerosa protects the cells from apoptosis. Discussion and conclusion: The results suggest that G. acerosa possesses excellent neuroprotective potential against peptide mediated toxicity under in vivo conditions

Antiaggregation Potential of Padina gymnospora against the Toxic Alzheimer's Beta-Amyloid Peptide 25-35 and Cholinesterase Inhibitory Property of Its Bioactive Compounds.

Inhibition of β-amyloid (Aβ) aggregation in the cerebral cortex of the brain is a promising therapeutic and defensive strategy in identification of disease modifying agents for Alzheimer's disease (AD). Since natural products are considered as the current alternative trend for the discovery of AD drugs, the present study aims at the evaluation of anti-amyloidogenic potential of the marine seaweed Padina gymnospora. Prevention of aggregation and disaggregation of the mature fibril formation of Aβ 25-35 by acetone extracts of P. gymnospora (ACTPG) was evaluated in two phases by Thioflavin T assay. The results were further confirmed by confocal laser scanning microscopy (CLSM) analysis and Fourier transform infrared (FTIR) spectroscopic analysis. The results of antiaggregation and disaggregation assay showed that the increase in fluorescence intensity of aggregated Aβ and the co-treatment of ACTPG (250 μg/ml) with Aβ 25-35, an extensive decrease in the fluorescence intensity was observed in both phases, which suggests that ACTPG prevents the oligomers formation and disaggregation of mature fibrils. In addition, ACTPG was subjected to column chromatography and the bioactivity was screened based on the cholinesterase inhibitory activity. Finally, the active fraction was subjected to LC-MS/MS analysis for the identification of bioactive compounds. Overall, the results suggest that the bioactive compound alpha bisabolol present in the alga might be responsible for the observed cholinesterase inhibition with the IC50 value < 10 μg/ml for both AChE and BuChE when compared to standard drug donepezil (IC50 value < 6 μg/ml) and support its use for the treatment of neurological disorders

Cholinesterase inhibitory, anti-amyloidogenic and neuroprotective effect of the medicinal plant Grewia tiliaefolia – An in vitro and in silico study

Context: Grewia tiliaefolia Vahl. (Tiliaceae) is a sub-tropical plant used as an indigenous medicine in India. However, its efficacy has not been evaluated against Alzheimer’s disease. Objectives: The objective of this study is to evaluate cholinesterase inhibitory, anti-aggregation and neuroprotective activity of G. tiliaefolia. Materials and method: Grewia tiliaefolia leaves were collected from Eastern Ghats region, India, and subjected to successive extraction (petroleum ether, chloroform, ethyl acetate, methanol and water). The extracts were subjected to in vitro antioxidant, anticholinesterase and anti-aggregation assays. The active methanol extract (MEGT) was separated using column chromatography. LC-MS analysis was done and the obtained compounds were docked against acetylcholinesterase (AChE) enzyme to identify the active component. Results: Antioxidant assays demonstrated that the MEGT showed significant free radical scavenging activity at the IC50 value of 71.5 ± 1.12 μg/mL. MEGT also exhibited significant dual cholinesterase inhibition with IC50 value of 64.26 ± 2.56 and 54 ± 0.7 μg/mL for acetyl and butyrylcholinesterase (BChE), respectively. Also, MEGT showed significant anti-aggregation activity by preventing the oligomerization of Aβ25–35. Further, MEGT increased the viability of Neuro2a cells up to 95% against Aβ25-35 neurotoxicity. LC-MS analysis revealed the presence of 16 compounds including vitexin, ellagic acid, isovitexin, etc. In silico analysis revealed that vitexin binds effectively with AChE through strong hydrogen bonding. These results were further confirmed by evaluating the activity of vitexin in vitro, which showed dual cholinesterase inhibition with IC50 value of 15.21 ± 0.41 and 19.75 ± 0.16 μM for acetyl and butyrlcholinesterase, respectively. Discussion and conclusion: Grewia tiliaefolia can be considered as a promising therapeutic agent for the treatment of AD

<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

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

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