“…The majority of previous studies on apple were conducted on the whole apple or tree, which basic part of the user of most and contains flavonoids, anthocyanin, and carotene as well as phenolic compounds (viz., procyanidin, chlorogenic acid, caffeic acid, quercetin, rutin) [2,3]. In particular, quercetin flavanol is an active ingredient in many plant medicines and is used in a variety of products ('Condition', CJ HealthCare, Seoul, Korea; 'Quercetin with bromelain', iHerb, Moreno valley, CA, USA) [1,4]. In addition, polyphenols, which are highly contained in apple peels, have preventive effects on diseases like endogenous and/or exogenous aging, skin aging, inflammation, and cancer caused by oxidative stress [4].…”