ASCORBIC ACID, TOTAL PHENOLICS AND ANTIOXIDANT ACTIVITY OF GUAVA LEAF EXTRACTS
Epidemiological studies have indicated that guava leaf extract can act as an anti-free radical reagent, which could reduce the risk of several cancer types. The objective of this research was to investigate ascorbic acid content, total phenolics content and antioxidant activity in guava leaf extracts of 30 cultivars consisting of 10 dessert, 12 processing and 8 local types. The results showed that guava leaf extracts from processing type had the highest level of total phenolic content (gallic acid equivalents) at 5,304±1,485 mg/100 g fresh weight (FW) and antioxidant activity (ascorbic acid equivalents) at 685±135 µmol/g FW. The highest value of ascorbic acid was found in local type at 98±21 mg/100 g FW. Green leaf had higher value of phenolic content (4,584±1,710 mg/100 g FW) and antioxidant activity (559±242 µmol/g FW) than maroon leaf. While, maroon leaves contained higher value of ascorbic acid than green leaves that were 142±52 and 86±29 mg/100 g FW, respectively. Therefore, antioxidants in guava leaf should be extracted from the green processing type in order to get the highest value.
Iamjud, K., Banyen, N., Boonprakob , U. and Thaipong, K. (2014). ASCORBIC ACID, TOTAL PHENOLICS AND ANTIOXIDANT ACTIVITY OF GUAVA LEAF EXTRACTS. Acta Hortic. 1024, 367-372
antioxidant properties, natural antioxidant, ascorbic acid content