Optimized extraction of polyphenolic antioxidants from the leaves of Himalayan Oak species.

Aseesh Pandey,Ranbeer S Rawal,Sushma Tamta,Tarun Belwal,Christophe Hano

doi:10.1371/journal.pone.0259350

Aseesh Pandey, Ranbeer S Rawal + Show 3 more

Open Access

https://doi.org/10.1371/journal.pone.0259350

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Abstract

In this study heat-assisted extraction conditions were optimized to enhance extraction yield of antioxidant polyphenols from leaves of Himalayan Quercus species. In initial experiments, a five-factor Plackett-Burman design including 12 experimental runs was tested against the total polyphenolic content (TP). Amongst, XA: extraction temperature, XC: solvent concentration and XE: sample-to-solvent ratio had shown significant influence on yield. These influential factors were further subject to a three-factor-three-level Box-Wilson Central Composite Design; including 20 experimental runs and 3D response surface methodology plots were used to determine optimum conditions [i.e. XA: (80°C), XC:(87%), XE: (1g/40ml)].This optimized condition was further used in other Quercus species of western Himalaya, India. The High-Performance Liquid Chromatography (HPLC) revealed occurrence of 12 polyphenols in six screened Quercus species with the highest concentration of catechin followed by gallic acid. Amongest, Q. franchetii and Q. serrata shared maximum numbers of polyphenolic antioxidants (8 in each). This optimized extraction condition of Quercus species can be utilized for precise quantification of polyphenols and their use in pharmaceutical industries as a potential substitute of synthetic polyphenols.

Highlights

The health benefits of polyphenols to human beings have been attracted attention to them worldwide and these beneficial properties of polyphenols are generally accredited to their antioxidant nature [1]
Among six Quercus species examined in the present study, Q. semecacrpifolia and Q. serrata exhibited significantly higher levels of polyphenols under the optimized extraction condition i.e. extraction temperature (80 ̊C), solvent concentration of (87%; 0.2N methanol), sample-tosolvent ratio (1: 40), solvent pH (2), and extraction time (45 min)
Gallic acid was observed in all the tested Quercus species highest catechin concentration was observed for Q. floribunda

Summary

Introduction

The health benefits of polyphenols to human beings have been attracted attention to them worldwide and these beneficial properties of polyphenols are generally accredited to their antioxidant nature [1]. Polyphenolic antioxidants (PA) are structural class of organic chemicals which contain phenol units and based on their origin PAs can be classified in two categories i) synthetic and ii) natural. These are classified into i) Phenolic acids ii) Flavonoids iii) Lignans and iv) Stilbenes. Have been used in product formulations since 1950s in order to prevent or delay the onset of lipid oxidation during processing and storage of fats, oils and lipid containing foods [2].

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