Anti-Inflammatory, Free Radical Scavenging, and Reducing Activities of Malus × domestica Borkh. Apples Extracts

Abstract

Background. Cancer initiation and development are closely related to oxidative stress and chronic inflammation. It has been established that many elements of a vegetarian diet, especially fruits and vegetables can prevent the development of cancer. Apples are one of the most consumed fruits worldwide. In nutrition, apples are a relevant source of phenolic and triterpenic compounds, which possess anti-inflammatory and antioxidant activities, neutralizing harmful reactive free radicals that trigger structural damage to the body’s macromolecules, which, in turn, is directly related to the progression of various diseases including inflammatory diseases and cancer. Aim. The aim of this study was to evaluate apple extracts antioxidant, and anti-inflammatory activities in vitro. Methods. This study included the five apple cultivars ‘Auksis’, ‘Kostele’, ‘Ligol’, ‘Paprastasis antaninis’, and ‘Rubin’. Free radical scavenging, and reducing activities were estimated, using spectrophotometrical DPPH, ABTS, FRAP, and CUPRAC assays, respectively. Results of antioxidant activity assays were expressed as micromolar of Trolox (μM TE/g DW). Anti-inflammatory activity was determined evaluating hyaluronidase (HYAL) inhibition. The absorbances of the test solutions were measured at multi scan plate reader. HYAL inhibition was calculated: HYAL inhibition (%)=100×(1–[Absorption of sample/Absorption of control]). Results. The radical scavenging activity assessed by DPPH and ABTS assays ranged between 19.37 to 328.32 μM TE/g, and 67.07 to 805.52 μM TE/g, respectively. The reducing activity estimated by CUPRAC and FRAP assays ranged between 3.24 to 70.81 μM TE/g, and 229.83 to 3191.09 μM TE/g, respectively. The strongest antiradical and reducing effects were determined of apple extracts of ‘Paprastasis antaninis’ cultivar. Apple extracts inhibited hyaluronidase from 26.38 to 35.05 %. The strongest inhibition activity of hyaluronidase was evaluated in the apple extracts of ‘Kostele’ cultivar. A moderate positive correlation (rDPPH=0.397, rABTS=0.422, rFRAP=0.420, and rCUPRAC=0.449) between the antioxidant and hyaluronidase inhibition activities of apple extracts was found. Conclusion. Understanding the mechanisms of apple extracts and their biological active compounds as hyaluronidase inhibitors and antioxidants may be a useful tool for future study in vivo, or development of new, innovative food supplements that could be used for prevention of chronic diseases