Extraction, purification and anticancer activity studies on triterpenes from pomegranate peel

Pomegranate peel is the by-product of pomegranate processing, which contains a lot of triterpene compounds. In this study, the total triterpenes of pomegranate peel (TPP) were extracted using an ultrasonic-assisted ethanol extraction method under optimal conditions, purified using D-101 macroporous resin to obtain a purity of 75.28%. The triterpenes in TPP were mainly pentacyclic triterpenes determined by LC-MS/MS. Network pharmacological analysis predicted that the anticancer targets were closely related to the MAPK pathway. The in vitro results showed that TPP could inhibit cell proliferation, promote apoptosis, reduce mitochondrial membrane potential and increase ROS levels. The western blot results indicated that the expression levels of the apoptotic proteins Bax, Bcl-2, cytochrome C, cleaved caspase-3 and cleaved caspase-9 were increased. In addition, the protein expression of the MAPK pathway predicted by network pharmacology also changed significantly. These results provided that TPP has potential for adjuvant therapy of tumors.