We investigated the antioxidant and cholinesterase inhibitory activities of the aqueous extract of rainbow trout
The overproduction of free radical species causes oxidative stress that contributes to cellular aging and neuronal damage, and it is associated with chronic degenerative diseases, including Alzheimer’s disease(AD) (Sastre et al., 2000). AD, a progressive neurodegenerative disorder that is commonly seen in elderly individuals, is characterized by memory and cognitive ability loss, behavior disturbances, and personality changes (Bachman et al., 1992). The etiology of AD remains unclear; one of the most convincing theories is the cholinergic hypothesis,which implicates a deficiency in neurotransmitters,such as acetylcholine (ACh) and butyrylcholine(BCh) (Schneider, 2001). Efforts to prevent AD have focused on the activation of cholinergic functions through the inhibition of cholinesterase (ChE), which hydrolyzes the cholinergic neuromediators and reduces oxidative stress (Schneider, 2001).
In the present study, the antioxidant and ChE inhibitory activities of
Reducing power was evaluated by the method of Oyaizu (1986). Various concentrations of samples(2.5 mL) were mixed with 2.5 mL of 200 mM sodium phosphate buffer (pH 6.6) and 2.5-mL of 1%potassium ferricyanide. After incubation at 50°C for 20 min, 2.5 mL of 10% trichloroacetic acid (w/v) was added. The mixture was centrifuged at 2,000 g for 10 min, and 5 mL of the upper layer was mixed with deionized water and 1 mL of 0.1% ferric chloride.Absorbance was measured at 700-nm using a spectrophotometer (Powerwave XS; Bio-Tex, Inc.,Houston, TX, USA). L-ascorbic acid was used as a positive control.
ONOO- scavenging activity was measured by the method of Kooy et al. (1994) with minor modification.Each sample was mixed with rhodamine buffer (pH 7.4) and 5 mM dihydrorhodamine (DHR)123. After incubation for 5 min, the sample was treated with authentic ONOO-. The fluorescence intensity of the oxidized DHR 123 was measured with a microplate fluorescence reader (Wallac 1420;PerkinElmer, Waltham, MA, USA) at excitation and emission wavelengths of 485 nm and 530 nm,respectively. L-ascorbic acid was used as a positive control.
Inhibitory activity against ChE was measured using the spectrophotometric method developed by Ellman et al. (1961). The reaction mixture contained 140 mL of sodium phosphate buffer (pH 8.0), 20 μL of sample, and 20 μL of either AChE (0.36 U/mL) or BChE (0.36 U/mL). The solution was placed in a 96-well microplate, mixed, and incubated at room temperature for 15 min. After incubation, 10 μL of
Ellman’s reagent and 10 μL of ACh or BCh were added. The absorbance of all reactions was measured using a spectrophotometer (Powerwave XS; Bio-Tex,Inc.). Eserine was used as a positive control.
The proximate composition analysis was performed using the methods described by the Association of Official Analytical Chemists (1995).
Antioxidant properties are related to radical scavenging and reduction capacities. ONOO- is a strongly oxidizing and nitrating species that induces lipid peroxidation, thiol oxidation, and amino acid modification and causes DNA damage. ONOO- overproduction may cause several neurological diseases, such as AD and Parkinson’s disease(Squadrito and Pryor, 1998). Reduction is related to the donation of hydrogen atoms to ferric complexes and can disturb reactions between radicals (Singh and Rajini, 2004).
The antioxidant activity of
According to Atif et al. (2006) and Oh et al. (2008), fish in the Salmonidae family contain small quantities
of several bioactive constituents, including phenolic ingredients and metallothioneins, which have shown positive correlations with antioxidant activity. The antioxidant activities of
ChE inhibitors are recognized as the most promising therapeutic agents for AD, and have been shown to affect cognitive and behavioral symptoms in clinical studies (Giacobini, 2004). AChE inhibitors increase the endogenous levels of ACh and cholinergic neurotransmission. BChE inhibitors decrease the accumulation of neural plaques in senile brains.Thus, the achievement of a balance between AChE and BChE inhibitors may increase the efficacy of treatment (Yu et al., 1999).
The ChE inhibitory activity of
The proximate composition of
lipid, and ash contents of