Study of the antioxidant activity and polyphenol content of "Wonderful" pomegranate aril juices and peel extracts obtained using different extraction methods

Abstract

Punica granatum L., commonly known as pomegranate, has become a very popular fruit of great interest mainly because of its various phytochemical content, particularly polyphenolic compounds, which have been shown to exert a great number of bioactive functions. Recent investigations have shown the health promoting effects of the fruit as an antioxidant and anti-inflammatory agent against oxidative stress and inflammatory mediator-induced chronic diseases like cancer, cardiovascular diseases, and neurodegenerative disorders. The arils, skins and seeds of the fruit are high in antioxidants, flavonoids and tannins that lend it its medicinal properties. More importantly, punicic acid, a predominant bioactive constituent of pomegranate seed oil, has been extensively investigated for its anti-inflammatory and anticarcinogenic activities. Although the health benefits of pomegranates are known, antioxidant activity may completely depend on the environmental factor, the variety of fruit and the processing method, and therefore it may be difficult to standardize the health claim. This thesis emphasises on extraction methods that are used to improve the extraction yield and bioactivity of pomegranate bioactives. Several techniques such as solvent extraction, ultrasound-assisted extraction, and supercritical fluid extraction have been investigated to improve polyphenolic compounds extraction. The quality and the biological activity of the derived products are influenced by the strength and weakness of each extraction methods. One specific example is pomegranate oil, a juice-pressing by-product that has attracted attention due to its rich punicic acid and antioxidant content, which has positioned it as a "superfood" possessing substantial health-promoting properties. The oil also has other uses apart from food, such as in pharmaceutical, or cosmetic, and is even used in the cosmetic industry for its regenerating and wound healing effects. Furthermore, preliminary studies show that punicic acid may inhibit the growth of cancer cells and induce apoptosis, which suggests that it may serve as a cancer therapeutic. This review attempts to further clarify the intricate relationship between pomegranate bioactives and their extraction procedures, particularly on the recovery of phenolic compounds and their correlation with health benefits. A literature review in combination with experimental results is intended to illustrate the health promoting capacities of pomegranate in disease prevention and health promotion, emphasizing the potential of pomegranate-based products. The results emphasize the necessity to optimize extraction methods in order to improve the bioactive composition of pomegranate products and to promote their use in developing nutraceutical and pharmaceutical products. Given that future research will likely uncover novel bioactive mechanisms of action, pomegranate can be established as a promising, cost-effective adjunct or functional food with widespread applicability for the chronic diseases, thereby enhancing public health.