author(s)
Manish Kumar and Arzoo Jangra

abstract
The present study was carried out to extract and estimate the different flavonoid compounds in different parts of grapefruit. Grapefruit used in this study was procured from Dehradun (UK). Peel of fruit was removed manually followed by collection of pulp and seed. Peel, pulp and seed collected were dried by two methods: Oven drying at 45-50 0C (OD) and freeze drying at -76 0C (FD). Dried samples were grounded to powder prior to extraction of flavonoids by using two methods: Soxhlet assisted extraction (SAE) and Ultrasonic assisted Extraction (UAE) using methanol as a solvent. The estimation of flavonoids was carried out on UPLC. Apigenin (4192.7 µg/g), Naringenin (19656 µg/g), Hesperidin (2999.95 µg/g), Quercetin (1429.19 µg/g), Rutin (994.17 µg/g), Epicatechin (984.33 µg/g), Daidzein (307.21 µg/g) were recorded in oven dried peels extracted via SAE method. Flavonoid content in freeze dried pulp sample extracted via SAE method had shown the maximum content of Naringenin (21109.9 µg/g) followed by Epicatechin (1080.32 µg/g), Apigenin (591.58 µg/g), Daidzein (552.92 µg/g), Hesperidin (391.83 µg/g), Rutin (277.75 µg/g) and Quercetin (252.21 µg/g). Daidzein 14.1 µg/g was least recorded flavonoids in oven dried seed sample processed via SAE method. While the maximum flavonoids reported in oven dried content was also processed via UAE seed sample method that is Naringenin (15800.4 µg/g).