Phytol ameliorated benzo(a)pyrene induced lung carcinogenesis in Swiss albino mice via inhibition of oxidative stress and apoptosis.

In the present study, the modulatory effect of phytol against benzo(a)pyrene [B(a)P] induced lung carcinogenesis was investigated in Swiss albino mice. During the experimental period, phytol treatment showed no adverse toxic effect and mortality to the experimental animals. Lung tumor was observed in B(a)P treated group and also in animals post-treated with low concentration (50 mg/kg) of phytol. No neoplastic changes were observed in the lung tissue of the animals treated with the maximum dose of phytol (100 mg/kg). An elevated level of antioxidant enzymes combined with macromolecular damage (lipid peroxidation, protein carbonyl content) was observed upon B(a)P treatment whereas, phytol restored the level of antioxidant enzymes which were comparable to the vehicle control group. Moreover, administration of B(a)P induced apoptosis, as observed by the highest expression of Bax, caspase-3, and caspase-9 proteins in lung tissue of B(a)P alone treated animals. However, phytol treatment reduced the expression of Bax, caspase-3, and caspase-9 protein and maintained the constant expression of anti-apoptotic protein Bcl-2. These observations positively reveal that phytol regulates the antioxidant enzymes and thereby protects the cells against B(a)P induced carcinogenesis without showing any adverse toxic effect to the animals.

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 Aß25-35. Further, MEGT increased the viability of Neuro2a cells up to 95% against Aß25-35 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.

In vitro antiaggregation and deaggregation potential of Rhizophora mucronata and its bioactive compound (+)- catechin against Alzheimer's beta amyloid peptide (25-35).

OBJECTIVE: Amyloid hypothesis states that endogenous ß-amyloid peptides (Aß), especially its aggregated oligomers and fibrils are the key pathogenic factors leading to Alzheimer's disease (AD). Therefore, inhibition of Aß 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 Aß (25-35). METHODOLOGY: Antiaggregation and disaggregation effect by MERM and (+)- catechin against Aß (25-35) were assessed in three different phases by thioflavin T (ThT) fluorescence assay and confocal microscopic analysis. The conformational changes in the aggregated Aß 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 Aß 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 ß-structured aggregates of Aß peptide. CONCLUSION: Results suggest that MERM and catechin might have direct interaction with Aß peptide preventing its fibrillation.

Olive oil and its phenolic compounds (hydroxytyrosol and tyrosol) ameliorated TCDD-induced heptotoxicity in rats via inhibition of oxidative stress and apoptosis.

CONTEXT: Naturally occurring polyphenols including olive oil (OO) and its constituents hydroxytyrosol (HT) and tyrosol (TY), consumed in the Mediterranean diet, have shown to treat various ailments due to their remarkable antioxidant properties. OBJECTIVE: The present study investigates the hepatoprotective effects of OO and its phenolic compounds HT and TY against TCDD-induced hepatotoxicity in male Wistar rats. MATERIALS AND METHODS: TCDD was administered at a dose of 100 ng/kg p.o. for 20 d. Administration of OO (10 ml/kg; oral), HT (0.5 mg/kg; oral), and TY (30 mg/kg; i.p) was started 5 d prior to TCDD administration, and continued for 25 d with or without TCDD administration. At the end of the experiment (25 d), blood was taken for biochemical analyses and liver for the measurement of macromolecular damages, antioxidant status, expressions of CYP1A1, and apoptotic factors. RESULTS: TCDD administration resulted in significant (p < 0.05) increase in the level of hepatic stress markers ALT (101.6 ± 3.07 IU/l), AST (295.0 ± 3.0 IU/l), and ALP (266.66 ± 3.7 IU/l). Also, biochemical analyses of liver reported elevation in nitrite and protein carbonyl content and depletion of NQO1 and HO. However, OO, HT, and TY restored the antioxidant status. Protein expressions by Western Blot technique showed an increase in the level of CYP1A1 and Bax and a decreased level of Bcl-2 on TCDD treatment, and vice versa on OO, HT, and TY treatment. DISCUSSION AND CONCLUSION: Our work concludes that dietary supplementation of OO, HT, and TY could serve as a potential preventive drug for TCDD-induced hepatotoxicity.

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 ß-amyloid (Aß) 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 Aß 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 Aß and the co-treatment of ACTPG (250 µg/ml) with Aß 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.