Kluai Hin (Musa sapientum Linn.) peel as a source of functional polyphenols identified by HPLC-ESI-QTOF-MS and its potential antidiabetic function

Patthamawadee Tongkaew,Chalermchai Mitrpant,Ebru Aydin,Anna Tohraman,Ramlatee Bungaramphai

doi:10.1038/s41598-022-08008-3

Patthamawadee Tongkaew, Chalermchai Mitrpant + Show 3 more

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https://doi.org/10.1038/s41598-022-08008-3

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Abstract

To date, information on the polyphenolic composition of Kluai Hin banana peel and pulp and the potential antidiabetic activity of its major active compounds is limited. This study aimed to identify polyphenols in extracts of fresh and freeze-dried Kluai Hin banana peel and pulp (methanol:water; M:W, 80:20 for flavonoids and acetone:water:acetic acid; A:W:A, 50:49:1 for phenolic acids) by RP-HPLC-DAD and HPLC-ESI-QTOF-MS. Additionally, inhibition of α-amylase and α-glucosidase activities was investigated with crude extracts from Kluai Hin banana peel and pulp, and compared with its major polyphenols ((+)-catechin, (−)-epicatechin and gallic acid) and the antidiabetic drug acarbose. (−)-Gallocatechin was the most abundant polyphenol and was detected in all fresh and freeze-dried pulp and peel extracts by RP-HPLC-DAD. Furthermore, unidentified polyphenol peaks of Kluai Hin were further explored by HPLC-ESI-QTOF-MS. The A:W:A fresh peel extract contained more total phenolic content (811.56 mg GAE/100 g) than the freeze-dried peel (565.03 mg GAE/100 g). A:W:A extraction of the fresh and freeze-dried peel of exhibited IC50 values for α-amylase activity 2.66 ± 0.07 mg/ml and 2.97 ± 0.00 mg/ml, respectively, but its inhibitory activity was lower than acarbose (IC50 = 0.25 ± 0.01 mg/ml). Peel extracts inhibited α-glucosidase activity, whereas pulp extracts had no effect. In addition, all standards, except gallocatechin, activated α-amylase activity, while, gallocatechin inhibited α-glucosidase activity better than acarbose. Therefore, we propose a further investigation into the use of Kluai Hin banana peel as a potential functional food for the management of postprandial glycaemic response to reduce diabetes risk and in the management of diabetes with a commercial drug.

Highlights

Abbreviations AWA Acetone:water:acetic diode array detector (DAD) Diode array detector electrospray ionization source (ESI) Electrospray ionization source FW Fresh weight gallic acid equivalent (GAE) Gallic acid equivalent HPLC High performance liquid chromatography MS Mass spectrometer MW Methanol:water QTOF Quadrupole-time of flight RP Reverse-phase
The estimated amount of total phenol was obtained by the Folin-Ciocalteu method, while, the reverse phase-high-performance liquid chromatography-diode array detector (RP-HPLCDAD) is more specific for identification and quantification of polyphenols compared to standards
A polyphenol profile was identified for the first time in Kluai Hin by RP-HPLC-DAD and HPLC-ESI-QTOF-MS

Summary

Introduction

Abbreviations AWA Acetone:water:acetic DAD Diode array detector ESI Electrospray ionization source FW Fresh weight GAE Gallic acid equivalent HPLC High performance liquid chromatography MS Mass spectrometer MW Methanol:water QTOF Quadrupole-time of flight RP Reverse-phase. An advanced, high sensitive and effective method, liquid chromatography coupled with electrospray-ionization and quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS) was used to characterize diverse and complex polyphenols from different fruit peels, including banana p eel[9]. The present study aimed to investigate the Kluai Hin peel and pulp polyphenols by RP-HPLC-DAD and HPLC-ESI-QTOFMS along with their inhibitory activity on α-amylase and α-glucosidase enzymes. This study hypothesised that different parts of the Kluai Hin banana (pulp and peel) will contain different types of polyphenols using different extraction solutions. The Kluai Hin banana is a potential candidate for a functional source of polyphenols and possible delays carbohydrate digestion and postprandial glucose absorption through inhibiting α-amylase and α-glucosidase activity, resulting in higher consumption and decrease the risk of diabetes. Kluai Hin peels, a natural by-product of banana, will be utilized more as a functional ingredient in functional food development

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