Characterization of free, esterified and bound phenolics in custard apple (Annona squamosa L) fruit pulp by UPLC-ESI-MS/MS

• Custard apple (Annona squamosa L) fruits are good source of phenolic compounds.
• Phenolic profile in free, bound and esterified form has been fingerprinted using UPLC-ESI-MSMS.
• The phenolics identified fall into benzoic acid and cinnamic acid derivatives and flavanol group.
• Some of the phenolics like quinic acid, gallocatechin are reported for the first time in this fruit.

Ultra high-performance liquid chromatography-electrospray ionization mass spectrometry (UPLC-ESI-MS) was used to identify the free, bound and esterified phenolic acids in the extracts of custard apple (Annona squamosa L). In total around 16, 15 and 13 free, bound and esterified phenolic compounds respectively were identified. Among these about 5 phenolic compounds like quinic acid, gallocatechin, gallocatechin gallate, caffeoylhexoside, dihydroxyquercetin have and been reported for the first time in A.squamosa. Also, compounds like 4-(β-d-glucopyranosyloxy) benzoic acid, procyanidin B1, procyanidin C1 in free form, 7 hydroxycoumarin 7 glucoside (skimmin), dihydroquercetin, xanthotaxol acetate, decycloxybenzoic acid in bound extract and caffeoyl hexoside in esterified form have been tentatively identified. Apart from phenolic compounds few organic acids like malic, citric, citramalic, adipic and acotinic acid have been found in the custard apple extracts. This study provides a newer insight into the phenolic profile of custard apple and their characterization by UPLC-ESI-MS/MS.