Method optimization for enhanced bioactive compounds extraction from hazelnut (&lt;em&gt;Corylus avellana&lt;/em&gt; L.) involucre: Phytochemical profile and antioxidant activity

Marius Rusu,Andrei Mocan,Ioan Tomuta,Daniela-Saveta Popa,Ana-Maria Gheldiu,Laurian Vlase

doi:10.3390/ecmc-4-05570

Abstract

The increasing use of healthy unsaturated fats, more prone to oxidation, the understanding of the pathology of oxidative stress in the organisms, and the negative side-effects of some synthetic antioxidant compounds point to the research of natural antioxidants of plant origin which could be used in pharma or food industry. In this study, the polyphenolic composition and in vitro antioxidant activity of the acetone extracts of hazelnut involucre (HI) were assayed. Optimum extraction conditions, based on an experimental design, were developed to obtain HI extracts rich in bioactive compounds. The best responses per gram of dry weight (dw) HI were in the range of 332 – 377 mg GAE (gallic acid equivalents) for total phenolic content (TPC); 37 – 43 mg QE (quercetin equivalents) for total flavonoid content (TFC); 24 – 28 mg CE (catechin equivalents) for condensed tannin content (CTC). The highest values for total antioxidant activity (TAA), determined by TEAC method, were in the range of 1,296 to 1,811 mg TE (Trolox equivalents) per gram of dw HI. A good relationship was observed between TPC, TFC, CTC, and TAA, the best results were found for the equal mixture (1:1) of acetone and water, as the extraction solvent. Further, for the richest polyphenolic HI extract, the phytochemical profile was examined by HPLC-MS/MS and several phenolics (epicatechin, catechin, syringic acid, gallic acid, protocatechuic acid, vanillic acid, hyperoside, quercitrin, isoquercitrin) and phytosterols (stigmasterol, campesterol, beta-sitosterol) were quantified. To the best of our knowledge, this is the first study to assay the detailed composition in both hydrophilic and lipophilic bioactive compounds in hazelnut involucre. The phytochemical profile and the biological activity of the analyzed extract prove that this plant matrix can be a valuable source of bioactive compounds for food and/or pharmaceutical industry.

Highlights

A diet rich in tree nuts, as many studies demonstrated, present benefit for human health
The best results for Total phenolic content (TPC), Total flavonoid content (TFC), Condensed tannin content (CTC), TAA obtained using binary-solvent systems compared to mono-solvent systems (Table 1)
The best results for TPC, TFC, CTC were obtained for 50% water in acetone and pH 7 (Figure 2, Figure 3, Figure 4)

Summary

Introduction

A diet rich in tree nuts, as many studies demonstrated, present benefit for human health. MARIUS EMIL RUSU1*, ANDREI MOCAN2, ANA-MARIA GHELDIU2, IOAN TOMUTA1, LARIAN VLASE1, DANIELA-SAVETA POPA3 Several of these benefits extend to their by-products. The aim of this research was to assess the phytochemical profile and the in vitro antiRoexsiudltas nt activity of the acetone extracts Taoblef1.hazelnut involucre (HI) based on an experimental design.

Objectives

Results

Conclusion