Bergenin, A Nigerian Alcoholic Beverage Additive From Sacoglottis Gabonensis As An Antioxidant Protector Of Mammalian Cells Against 2,4—Dinitrophenyl Hydrazine-Induced Lipid Peroxidation
H Maduka, Z Okoye
2, 4-dinitrophenyl hydrazine, antioxidants, ascorbic acid, bergenin, brain cells, lipid peroxidation, liver cells, malonaldehyde, malondialdehyde, red blood cells
H Maduka, Z Okoye. Bergenin, A Nigerian Alcoholic Beverage Additive From Sacoglottis Gabonensis As An Antioxidant Protector Of Mammalian Cells Against 2,4—Dinitrophenyl Hydrazine-Induced Lipid Peroxidation. The Internet Journal of Toxicology. 2005 Volume 3 Number 1.
The effect of bergenin isolated from Sacoglottis gabonensis bark extract, on membrane lipid peroxidation and tissue ascorbic acid level was studied using rat as the experimental animal and 2,4-dinitrophenyl as the experimental oxidant.
Pretreatment with bergenin significantly reduced but did not completely abolish DNPH-induced lipid peroxidation in the liver,brain and red blood cell as evidenced from the levels of the two intermediates, lipid hydroperoxide and aldehydes, measured. Bergenin also protected against DNPH-induced depletion of tissue ascorbic acid and had a sparing effect in untreated animals. The results suggest that bergenin may be responsible for the earlier observed anti-lipid peroxidizing effect of the bark extract.
We have recently examined the antioxidant activity of the crude extract in the mammalian system in detail using 2,4-dinitrophenyl hydrazine as the experimental peroxidant. The crude extract was found to effectively inhibit experimental lipid peroxidation in the liver, brain and red blood cells as determined by the tissue concentrations of three stable intermediates of the lipid peroxidation pathway, lipid hydroperoxide, lipid hydroperoxide carbonyl and lipid aldehyde (Maduka and Okoye 2002a). The crude extract was subsequently shown to exert a sparing effect on tissue antioxidant vitamins, ascorbic acid and vitamin E, protecting them against the 2,4-DNPH-induced depletion in the liver, brain and red blood cell, and to remove the inhibitory effect of 2,4-DNPH on the activity of the antioxidant enzyme, superoxide dismutase (Maduka and Okoye 2002b).
This paper reports on a study on the effect of bergenin isolated from
Materials And Methods
Isolation of Bergenin
Bergenin was isolated from the 4% aqueous ethanol extract of freshly harvested
Animal Treatment and Tissue Sample Collection
Weanling male wistar strain rats (body weight 90-120g) used in the study were obtained from the animal house of the Nigerian Institute of Trypanosomiasis Research (NITR), Vom, and left for 3 days to acclimatize to their new environment. During the period, they were fed ECWA laboratory chow and drinking water only. At the end of the period, the rats were distributed randomly and evenly into five standard metal/plastic rat cages, four rats per cage, such that the mean weights of the groups were about equal. The groups were labeled 1-5 respectively. Rats in groups 4 and 5 were given (1:10w/v) aqueous solution of bergenin
Biochemical Analyses of Samples
Lipid hydroperoxide content was determined as malondialdehde by the method of Hunter et al (1963) as modified by Kirkova et al (1995). Fatty acid aldehyde content was determined as malonaldehyde by the thiobarbituric acid method of Gutteridge (1984). Ascorbic acid determination was by the method of Roe and Kuether (1943) as modified by Tietz (1970). The data were analysed statistically by the student's t-test and confirmed by Mann-Whithney 2-Sample t-test.
The results are summarized on Tables 1-3. As can be seen from Tables 1 and 2, administration of DNPH expectedly induced lipid peroxidation in the three tissues, the values of the two intermediates determined (lipid hydroperoxide carbonyl and lipid aldehydes) being statistically higher in DNPH-treated rats (Group 3) than in the corresponding saline controls (Group 2). In both cases, pretreatment with bergenin significantly reduced the level of DNPH-induced peroxidation; the level of each intermediate was significantly lower in rats given DNPH after pretreatment with bergenin (Group5) than in non-pretreated rats given DNPH (Group 3). However, pretreatment with bergenin did not completely prevent oxidative damage by DNPH. As can be seen from Table 2, the concentration of the peroxidation intermediate, lipid aldehyde in each tissue was significantly higher in bergenin-pretreated rats given DNPH (Group 5) than in bergenin controls (Group 4). For lipid hydroperoxide carbonyl (Table 1), the difference was significant only in the case of the liver.
Tissue ascorbic acid content (Table 3) was generally lower in DNPH -treated rats (Group 3) than in the corresponding saline controls (Group 2) but the difference was significant only in the case of the red blood cell, suggesting marked DNPH-induced depletion. Ascorbic acid content of each of the three tissues was significantly higher in rats given DNPH after pretreatment with bergenin (Group 5) than in non-pretreated rats given DNPH (Group 3), an indication that bergenin protected against DNPH-induced depletion of liver, brain and red blood cell ascorbic acid. Also in each case, tissue ascorbic acid content of rats given only bergenin (Group 4) was significantly higher than in water controls (Group 1), suggesting that bergenin also protects against endogenous oxidants.
Ekong and Ejike (1974) first reported that bergenin isolated from
The initiation stage of lipid peroxidation is a free radical reaction with lipid hydroperoxides-products of the reaction between lipid peroxyl radical and oxygen-being the first stable intermediate (Wills 1987). Lipid hydroperoxides subsequently give rise to lipid aldehydes. The fact that pretreatment with bergenin reduced the levels of these two stable intermediates in experimental lipid peroxidation is an indication that the photochemical exerts its antioxidant action prior to the formation of the first stable intermediate. More work is required to understand the exact site and mode of action as well as the part of the bergenin molecule responsible for the antioxidant activity in a peroxidation reaction. However, in the case of the later, indications from reports on another antioxidant photochemical point to attachment of both polar and lipophilic substituent groups to the coumarin nucleus. For example, Sugiyama et al (1993) has shown that the presence of both polar and lipophilic substituent groups on the nucleus of purpurogallin molecule was responsible for its antioxidant properties against peroxyl radicals in human erythrocytes.
Theoretical mechanistic biochemistry concept has used the theoretical bioactivation of phenyl hydrazine-induced lipid peroxidation as well as the structure of bergenin as models ( Maduka,2005a and Maduka 2005b) to justify the observed antioxidant properties of Sacoglottis gabonensis(Maduka and Okoye,2002,Maduka et.al,2003).Theoretical mechanistic biochemistry relies on the structures of oxidants to predict their reactivities in tissues.From thje structure of bergenin,positions 1,2,3 and 4 are positions of antioxidant properties with positions 1 and 2 being greater than positions 3 and 4.Bergenin could give off any of the protons to react with the free radicals generated during the theoretical bioactivation scheme of phenyl hydrazine.
Ascorbic acid is a reducing agent which plays a general antioxidant role in the body. The observed reduction of its tissue level in experimental peroxidation is therefore, an indication that it participates in the body's antioxidant defences against xenobiotics like DNPH. Furthermore, the fact that the ascorbic acid sparing effect of bergenin was observed even in the absence of the experimental oxidant, DNPH is an indication that bergenin exerts antioxidant action on endogenous oxidizing agents as well.
Since similar antioxidant effect on lipid peroxidation and tissue ascorbic acid has been observed with the crude extract of
Which is an alcoholic beverage additive in Nigeria.The case being reported in this presentation is a typical case of manipulation of alcohol effects in the tissues described including the brain.
H.C.C. Maduka Department Of Biological Sciences, The University Of Hull, HU6 7RX, UK. E-mail: email@example.com
The investigations reported here were partly sponsored by Senate Research Grant No SRGC/1992/1993/001 University of Jos to Professor Z.S.C. Okoye, the Governing Council of University of Maiduguri who awarded study fellowship to Dr H.C.C. Maduka for a doctoral programme in Biochemical Toxicology under their staff development programme all in Nigeria.