Abstract: The antioxidant and acetyl cholinesterase inhibitory activities and polyphenol contents of ethanol extracts from the peel, pulp and pit of avocado fruits of four different cultivars were assayed and compared in this work. The results showed that the contents of total polyphenolics in three parts of avocado fruits ranged from 9.6 to 27.8 mg gallic acid equivalents (GAE) per gram dry weight. The antioxidant and acetyl cholinestera inhibitory activities of all samples were in a concentration-dependent manner. Among four avocado cultivars, the peel and kern of the Reed cultivar exhibited the greatest activity in scavenging 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and 2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical (ABTS＋·), as well as inhibiting acetyl cholinesterase, whereas the peel and pit of the Reyan 1 and Fuerte cultivars displayed the highest hydroxyl free radical scavenging activity. For the same variety, the activity of extracts from the peel and pit was much stronger than that of the pulp. Therefore, we should improve the utilization of inedible parts (peel and pit) of avocado fruits as much as possible during processing in order to turn the wastes into treasure and achieve high value-added utilization.

Key words: avocado, polyphenol, antioxidant, acetylcholine esterase