Extraction and Characterization of Phenolic Compounds from Bamboo Shoot Shell Under Optimized Ultrasonic-Assisted Conditions: a Potential Source of Nutraceutical Compounds

The extraction and characterization of bioactive compounds from bamboo shoot shell was performed under ultrasonic-assisted extraction (UAE) along with UPLC-Triple-TOF/MS analysis. Under optimized UAE conditions (ethanol concentration (58%), liquid to solid ratio (24 mL/g), extraction temperature (59 °C), and sonication time (29 min)), total phenolic content (TPC) was recorded highest as 85.3 mg GAE/g DW, while DPPH and FRAP antioxidant activities were 77 μmol AAE/g DW and 33 μmol AAE/g DW, respectively. Using UPLC-Triple-TOF/MS analysis, fifteen phenolic acids, seven flavonoids, nineteen organic acids, two iridoid glucosides, and one neoglinan were identified. Among them, p -coumaric acid (119 μg/g DW), chlorogenic acid (87 μg/g DW), rutin (39 μg/g DW), and ferulic acid (17 μg/g DW) were found to be the most abundant phenolic compounds. Furthermore, compounds including phenolic acids (3 -p- coumaroylquinic acid, cryptochlorogenic acid, 3 -O- feruloylquinic acid, 5 -O- feruloylquinic acid, 3 -O- caffeoylshikimic acid, 5 -p- coumaroylquinic acid, 1,3-dicaffeoyl quinic acid, 3,5-dicaffeoyl quinic acid), flavonoids (schaftoside/c-hexosyl-c-pentosylapigenin, apigenin 6,8-di-C-α- l -arabinopyranoside, kaempferide 3 -O- α- l -rhamnopyranosyl(1->6)-β- d -glucopyranoside, 6-C-β- d -glucopyranosyl-8-C-α- l -arabinopyranosylchrysin, narcissin), some organic acids, iridoid glucosides, and neolignan were also detected for the first time from bamboo shoot shell extract. The present study revealed that bamboo shoot shell extract contains a larger number of nutraceutically active compounds which can be further utilized by food and nutraceutical industries.