Evaluation of antioxidant and antiradical properties of Pomegranate (Punica granatum L.) seed and defatted seed extracts
Pomegranate seeds are byproducts of the Pomegranate juice industries that contains functional compounds such as phenols. This study was aimed to evaluate the effect of solvents on extraction from Pomegranate seed and Pomegranate defatted seed and to measure the yield extract and phenolic content and antioxidant properties. For this purpose, the seeds and defatted seeds were directly isolated from fruits and seeds by cold pressing respectively, then were crushed and extracted with different solvents, including water, Methanol, Acetone, Ethyl acetate and Hexane and finally the extracts of them were evaluted. Phenolic compounds, ferric reducing-antioxidant power and radicals scavenging property of extracts were measured. The results showed the highest extraction efficiencies were for Hexane and Acetone solvents in extraction of seed and defatted seed respectively. The highest phenolic content was obtained from Methanol seed extract. Reducing activity test proved that the Methanol extracts of Pomegranate seed and Pomegranate defatted seed had the highest reducing strength. Results of radical scavenging activity were similar to reducing activity results. The order of antioxidant capacity of Pomegranate seed and Pomegranate defatted seed were found to be Methanol > Water > Acetone > Butanol > Ethyl acetate > Hexane. It can be concluded Pomegranate seed, which possesses high levels of polyphenols, can be one of the sources of the natural antioxidants. The Methanol extract had a higher antioxidant efficiency than seed and defatted seed extracts.
Pomegranate (Punica granatum L.) is an important fruit of tropical and subtropical regions, which originated in the Middle East and India and has been used for centuries in ancient cultures for its medicinal purposes (Longtin 2003).
Pomegranate is consumed fresh and in processed form as juice, jelly, flavore and extract. It is widely reported that Pomegranate exhibits antivirus, antioxidant and anticancer activities (Faria et al. 2006; Faria et al. 2007; Adhami and Mukhtar 2006).
Over the past few years scientific investigations have laid some credible information for utilization of different parts of Pomegranate fruit (Aslam et al. 2006; Singh et al. 2002). Pomegranate seeds are byproducts of the Pomegranate juice industries. Pomegranate seed has powerful antioxidants, anti-inflammatory compounds, vitamin E, sterols, phenols and high quantities of valuable fatty acids such as punicic acid and natural estrogens (estradiol, estrone andestriol) (Fadavi et al. 2006; Lansky and Newman 2007). Antioxidant is defined as any substance that, when present at low concentrations compared with those of an oxidizable substrate, significantly delays or prevents oxidation of that substrate (Halliwell 1995). Many studies have shown the antioxidants contained in fruits and vegetables, including ascorbic acid, carotenoids, flavonoids, hydrolysable tannins, play an important role in the prevention of creation several diseases (Huxley and Neil 2003; Knekt et al. 2002 ; Lampe 1999). In Pomegranate fruit, antioxidant properties may be related to diverse phenolic compounds present in different parts of Pomegranate, including punicalagin isomers, ellagic acid derivatives and anthocyanins (delphinidin, cyanidin and pelargonidin 3-glucosides and 3,5-diglucosides). These compounds are known for their properties in scavenging free radicals and inhibiting lipid oxidation in vitro ( Noda et al. 2002). The Pomegranate antioxidant activity is typically higher in commercial juices extracted from whole Pomegranates than in experimental juices obtained from the arils only (Gil et al. 2000). Recently, natural antioxidants have become very popular for medical and food applications and are preferred by consumers than synthesized antioxidants, such as BHA and BHT (Lapornik et al. 2005; Landbo and Meyer 2001; Spigno and De Faveri 2007). Extraction is the first step in the commercial isolation of these antioxidant compounds from fruits. Because of the presence of large amounts of certain pharmaceutical, nutraceutical and antioxidant components in different parts of fruits such as Pomegranate, type of solvent to obtain these components is highly demanded in the food industry.
Accordingly, the objective of this study was to evaluate the effect of solvents with different polarity on extraction from Pomegranate seed (PS) and Pomegranate defatted seed (PDS) by measuring yield extract, phenolic content, in-vitro antioxidant activity, and ability to retard oxidation in a food oil model.