Protection against hydrogen peroxide induced oxidative damage in rat erythrocytes by Mangifera indica L. peel extract

Abstract

Phytochemicals such as polyphenols and carotenoids are gaining importance because of their contribution to human health and their multiple biological effects such as antioxidant, antimutagenic, anticarcinogenic and cytoprotective activities and other therapeutic properties. Mango peel is a major by-product in pulp industry and it contains various bioactive compounds like polyphenols, carotenoids and others. In the present study, the protective effect of peel extracts of unripe and ripe mango fruits of two varieties namely, Raspuri and Badami on hydrogen peroxide induced hemolysis, lipid peroxidation, degradation of membrane proteins and its morphological changes are reported. The oxidative hemolysis of rat erythrocytes by hydrogen peroxide was inhibited by mango peel extract in a dose dependent manner. The IC₅₀ value for lipid peroxidation inhibition on erythrocyte ghost membrane was found to be in the range of 4.5–19.3 μg gallic acid equivalents. The mango peel extract showed protection against membrane protein degradation caused by hydrogen peroxide. Morphological changes to erythrocyte membrane caused by hydrogen peroxide were protected by mango peel extract. The results demonstrated that mango peel extracts protected erythrocytes against oxidative stress and may impart health benefits and it could be used as a valuable food ingredient or a nutraceutical product.

Introduction

Reactive oxygen species (ROS) such as hydrogen peroxide, organo peroxide, super oxide anion and hydroxyl radical are generated in biological systems by aerobic metabolism and also by exogenous sources such as drugs, ultra violet light, ionizing radiation and pollution systems (Briviba and Sies, 1994). According to generally accepted mechanisms, major deleterious effects are caused by hydroxyl radical (OH^.) generated from H₂O₂ and by the superoxide (O₂^.−) species generated in the presence of redox active transition metals (Saumni et al., 1983, Chevion, 1988). Many endogenous and exogenous defense mechanisms are available in living organisms to limit the levels of ROS and the damage caused by them (Ames et al., 1993). These include antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase and many non-enzymatic antioxidant compounds such as polyphenols, tocopherols, ascorbic acid, uric acid, glutathione and other thiol protein groups to protect the functional and structural integrity of the biological molecules such as proteins, lipids and nucleic acids (Anderson and Phillips, 1999, Tavazzi et al., 2000). It has been reported that the unbalanced ROS production and antioxidant cell defenses have been associated in the physiological and pathological conditions such as aging, cancer, rheumatoid arthritis, atherosceloresis and neurodegenerative diseases (Rice-Evans and Burdon, 1993, Knight, 1997, Briviba and Sies, 1994, Barnham et al., 2004, Pardo-Andreu et al., 2006).

Epidemiological studies have strongly suggested that diet rich in fruits, vegetables and cereals play a crucial role in the prevention of chronic diseases such as cardiovascular diseases and certain types of cancer by quenching free radicals (Miller et al., 2000, Joshipura et al., 2001, Arouma, 2003). The beneficial health effects from the consumption of diet rich in fruits and vegetables are mainly due to the presence of antioxidants such as polyphenols, carotenoids and anthocyanins. Due to their susceptibility to oxidation, erythrocytes have been used as a cellular model to investigate oxidative damage in biomembranes. Erythrocytes are considered as prime targets for free radical attack owing to the presence of both high membrane concentration of polyunsaturated fatty acids (PUFA) and the O₂ transport associated with redox active hemoglobin molecules, which are potent promoters of reactive O₂ species (Sadrazadeh et al., 1984). Moreover, the free hemoglobin exposed to H₂O₂ causes heme degradation with the release of iron ions which catalytically active in initiating free radicals and lipid peroxidation (Puppo and Halliwell, 1988, Sadrazadeh et al., 1984). H₂O₂ and ascorbate/ Fe²⁺ induce an echinocytic type of shape alteration indicative of oxidative damage (Srour et al., 2000). Polyphenolics or anthocyaninins extracted from different fruits such as blue berry, grapes are found to be protect or increase resistance of erythrocytes to oxidative stress (Youdim et al., 2000, Carini et al., 2000, Tedesco et al., 2001).

Mango (Mangifera indica L.) is one of the important tropical fruits widely consumed. Mango fruit contains compounds such as polyphenols, carotenoids that posses antioxidant activity (Berardini et al., 2004, Talcott et al., 2005, Mahattanatawee et al., 2006), immunomodulatory activity (Naved et al., 2005), antimutagenic property (Botting et al., 1999) and anticancer activity (Percival et al., 2006). Recently aqueous stem bark extract from selected species of mango, which was used in pharmaceutical formulations and used as a food supplement in Cuba under the brand name of Vimang, has been reported to display a potent in vitro and in vivo antioxidant activity and anti-inflammatory activity, and also used to prevent age-associated oxidative stress (Martinez et al., 2000, Sanchez et al., 2000, Garrido et al., 2004, Rodriguez et al., 2006, Pardo-Andreu et al., 2006). Many of the pharmacological properties of mango fruit and stem bark of mango may be attributed to the presence of phytochemicals such as polyphenols, carotenoids, vitamins, etc. (Nunez-Selles et al., 2000, Singh et al., 2004). Mango peel is a major by-product of mango processing industry and it constitutes about 15–20% of total weight of mango fruit. Peel has been found to be a good source of phytochemicals such as polyphenols, carotenoids, vitamin E and vitamin C (Ajila et al., 2007a) and it exhibited good antioxidant property (Ajila et al., 2007b). Polyphenol content of peel was reported to be more than that of pulp (Lakshminarayana et al., 1979). Due to their antioxidant properties, these phytochemicals present in mango peel may exhibit protection against oxidative damage in cells by ROS. The aim of the present study is to evaluate the protective role of mango peel extract against H₂O₂ induced oxidative damage in normal rat erythrocytes.