Limits...
The Oxidative State of LDL is the Major Determinant of Anti/Prooxidant Effect of Coffee on Cu Catalysed Peroxidation.

Carru C, Pasciu V, Sotgia S, Zinellu A, Nicoli MC, Deiana L, Tadolini B, Sanna B, Masala B, Pintus G - Open Biochem J (2011)

Bottom Line: When the relative effects of different coffee concentrations were plotted against the lag time (LT) of control LDL (C-LDL), the apparently random experimental data arranged in sensible patterns: by increasing the LT the antioxidant activity of coffee decreased progressively to become prooxidant.The dependence of coffee effect on the LT of C-LDL was influenced by LDL but not by metal catalyst concentration.These novel findings point to the oxidative state of LDL as a major parameter controlling the anti/prooxidant effect of coffee and suggest the LT of C-LDL as a potent analytical tool to express experimental data when studying the action exerted by a compound on LDL oxidation.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43/B, 07100 Sassari, Italy.

ABSTRACT
Antioxidants exert contrasting effect on low density lipoprotein (LDL) oxidation catalysed by metals, acting as pro-oxidants under select in vitro conditions. Through our study on the effect of coffee on LDL oxidation, we identified the parameters governing this phenomenon, contributing to the comprehension of its mechanism and discovering significant implications for correct alimentary recommendations. By measuring conjugated diene formation, we have analysed the quantitative and qualitative effects exerted by an extract of roasted coffee on LDL oxidation triggered by copper sulphate. When the relative effects of different coffee concentrations were plotted against the lag time (LT) of control LDL (C-LDL), the apparently random experimental data arranged in sensible patterns: by increasing the LT the antioxidant activity of coffee decreased progressively to become prooxidant. The critical LT, at which coffee switches from antioxidant to prooxidant, increased by increasing coffee concentration. Also the contrasting results obtained following a delayed addition of coffee to the assay, arranged in a simple pattern when referred to the LT of C-LDL: the prooxidant effect decreased to become antioxidant as the LT of C-LDL increased. The dependence of coffee effect on the LT of C-LDL was influenced by LDL but not by metal catalyst concentration. These novel findings point to the oxidative state of LDL as a major parameter controlling the anti/prooxidant effect of coffee and suggest the LT of C-LDL as a potent analytical tool to express experimental data when studying the action exerted by a compound on LDL oxidation.

No MeSH data available.


Related in: MedlinePlus

The data reported in Table 2 and part of the data reported in Table 1 are presented. The length of the lag time obtained in the presence of coffee expressed as percentage of the lag time of control LDL was reported as a function of the lag time of control LDL. LDL (80 µg cholesterol) from different donors was incubated with either 1 µg (▲) or 4 µM (▀) copper sulphate in the absence or presence of 2 µg coffee. LDL oxidation was followed by monitoring the change of the conjugated diene absorbance at 234 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3104561&req=5

Figure 3: The data reported in Table 2 and part of the data reported in Table 1 are presented. The length of the lag time obtained in the presence of coffee expressed as percentage of the lag time of control LDL was reported as a function of the lag time of control LDL. LDL (80 µg cholesterol) from different donors was incubated with either 1 µg (▲) or 4 µM (▀) copper sulphate in the absence or presence of 2 µg coffee. LDL oxidation was followed by monitoring the change of the conjugated diene absorbance at 234 nm.

Mentions: However, when a similar experiment was repeated with different LDL preparations, quantitative and qualitative differences in coffee activity were observed, as shown by some representative results presented in Table 1. The effect exerted by 0.5 µg coffee, for instance, could range roughly from 50% shortening to 150% lengthening the LT. Trying to find a rationale to such an inconsistent behaviour we expressed the data as a function of various parameters. When the relative coffee effects exerted by 0.5 µg coffee in different experiments were plotted against the LT of C-LDL, the experimental data arranged in a sensible pattern (Fig. 2): by increasing the LT of C-LDL, the antioxidant activity of 0.5 µg coffee progressively decreases to become prooxidant when the LT exceeds 110-120 min. When the effect of higher coffee concentrations was evaluated, similar patterns were observed although the "critical" LT, at which coffee switches from antioxidant to prooxidant, increases (Fig. 2). We also studied the influence of copper concentration on the effect of coffee. In Table 2 and Fig. (3) are reported the results obtained when three LDL preparations were incubated either with 1 or 4 µM Cu2+ in the absence and presence of 2 µg coffee.


The Oxidative State of LDL is the Major Determinant of Anti/Prooxidant Effect of Coffee on Cu Catalysed Peroxidation.

Carru C, Pasciu V, Sotgia S, Zinellu A, Nicoli MC, Deiana L, Tadolini B, Sanna B, Masala B, Pintus G - Open Biochem J (2011)

The data reported in Table 2 and part of the data reported in Table 1 are presented. The length of the lag time obtained in the presence of coffee expressed as percentage of the lag time of control LDL was reported as a function of the lag time of control LDL. LDL (80 µg cholesterol) from different donors was incubated with either 1 µg (▲) or 4 µM (▀) copper sulphate in the absence or presence of 2 µg coffee. LDL oxidation was followed by monitoring the change of the conjugated diene absorbance at 234 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3104561&req=5

Figure 3: The data reported in Table 2 and part of the data reported in Table 1 are presented. The length of the lag time obtained in the presence of coffee expressed as percentage of the lag time of control LDL was reported as a function of the lag time of control LDL. LDL (80 µg cholesterol) from different donors was incubated with either 1 µg (▲) or 4 µM (▀) copper sulphate in the absence or presence of 2 µg coffee. LDL oxidation was followed by monitoring the change of the conjugated diene absorbance at 234 nm.
Mentions: However, when a similar experiment was repeated with different LDL preparations, quantitative and qualitative differences in coffee activity were observed, as shown by some representative results presented in Table 1. The effect exerted by 0.5 µg coffee, for instance, could range roughly from 50% shortening to 150% lengthening the LT. Trying to find a rationale to such an inconsistent behaviour we expressed the data as a function of various parameters. When the relative coffee effects exerted by 0.5 µg coffee in different experiments were plotted against the LT of C-LDL, the experimental data arranged in a sensible pattern (Fig. 2): by increasing the LT of C-LDL, the antioxidant activity of 0.5 µg coffee progressively decreases to become prooxidant when the LT exceeds 110-120 min. When the effect of higher coffee concentrations was evaluated, similar patterns were observed although the "critical" LT, at which coffee switches from antioxidant to prooxidant, increases (Fig. 2). We also studied the influence of copper concentration on the effect of coffee. In Table 2 and Fig. (3) are reported the results obtained when three LDL preparations were incubated either with 1 or 4 µM Cu2+ in the absence and presence of 2 µg coffee.

Bottom Line: When the relative effects of different coffee concentrations were plotted against the lag time (LT) of control LDL (C-LDL), the apparently random experimental data arranged in sensible patterns: by increasing the LT the antioxidant activity of coffee decreased progressively to become prooxidant.The dependence of coffee effect on the LT of C-LDL was influenced by LDL but not by metal catalyst concentration.These novel findings point to the oxidative state of LDL as a major parameter controlling the anti/prooxidant effect of coffee and suggest the LT of C-LDL as a potent analytical tool to express experimental data when studying the action exerted by a compound on LDL oxidation.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43/B, 07100 Sassari, Italy.

ABSTRACT
Antioxidants exert contrasting effect on low density lipoprotein (LDL) oxidation catalysed by metals, acting as pro-oxidants under select in vitro conditions. Through our study on the effect of coffee on LDL oxidation, we identified the parameters governing this phenomenon, contributing to the comprehension of its mechanism and discovering significant implications for correct alimentary recommendations. By measuring conjugated diene formation, we have analysed the quantitative and qualitative effects exerted by an extract of roasted coffee on LDL oxidation triggered by copper sulphate. When the relative effects of different coffee concentrations were plotted against the lag time (LT) of control LDL (C-LDL), the apparently random experimental data arranged in sensible patterns: by increasing the LT the antioxidant activity of coffee decreased progressively to become prooxidant. The critical LT, at which coffee switches from antioxidant to prooxidant, increased by increasing coffee concentration. Also the contrasting results obtained following a delayed addition of coffee to the assay, arranged in a simple pattern when referred to the LT of C-LDL: the prooxidant effect decreased to become antioxidant as the LT of C-LDL increased. The dependence of coffee effect on the LT of C-LDL was influenced by LDL but not by metal catalyst concentration. These novel findings point to the oxidative state of LDL as a major parameter controlling the anti/prooxidant effect of coffee and suggest the LT of C-LDL as a potent analytical tool to express experimental data when studying the action exerted by a compound on LDL oxidation.

No MeSH data available.


Related in: MedlinePlus