Optimization of a Green Ultrasound-Assisted Extraction of Different Polyphenols from Pistacia lentiscus L. Leaves Using a Response Surface Methodology.

Cassandra Detti,Luana Beatriz Dos Santos Nascimento,Francesco Ferrini,Cecilia Brunetti,Antonella Gori

doi:10.3390/plants9111482

Abstract

Pistacia lentiscus leaves are used in several applications, thanks to their polyphenolic abundance. Thiswork aimed to characterize the polyphenols and to optimize the extraction conditions to shorten the time, decrease the consumption of solvent, and to maximize the yield of different classes of phenolics, which have diverse industrial applications. The variables were optimized by applying a Box–Behnken design. Galloyl and myricetin derivatives were the most abundant compounds, and two new tetragalloyl derivatives were identified by LC-MS/MS. According to the models, the maximum yields of polyphenols (51.3 ± 1.8 mg g−1 DW) and tannins (40.2 ± 1.4 mg g−1 DW) were obtained using 0.12 L g−1 of 40% ethanol at 50 °C. The highest content of flavonoids (10.2 ± 0.8 mg g−1 DW) was obtained using 0.13 L g−1 of 50% ethanol at 50 °C, while 0.1 L g−1 of 30% ethanol at 30 °C resulted in higher amounts of myricitrin (2.6 ± 0.19 mg g−1 DW). Our optimized extraction decreased the ethanolic fraction by 25% and halved the time compared to other methods. These conditions can be applied differently to obtain P. lentiscus extracts richer in tannins or flavonoids, which might be employed for various purposes.

Highlights

Pistacia lentiscus L. (Anacardiaceae), known as mastic orlentisk, is an evergreen shrub, widespread over many areas in the Mediterranean basin [1]
Several studies have demonstrated that P. lentiscus leaves are rich in polyphenolic compounds [4,5]
Among the different factors that should be considered in ultrasound-assisted extraction, the polarity of the solvent and the solvent ratio is very important [45,47]

Summary

Introduction

Pistacia lentiscus L. (Anacardiaceae), known as mastic orlentisk, is an evergreen shrub, widespread over many areas in the Mediterranean basin [1]. (Anacardiaceae), known as mastic orlentisk, is an evergreen shrub, widespread over many areas in the Mediterranean basin [1]. This species is largely distributed in dry ecosystems, characterized by nutrient and water scarcity due to the long periods of drought, high irradiation, and temperatures [2,3]. Including gallotannins and flavonoids (mainly quercetin and myricetin derivatives) [6,7,8,9]. These two main classes of compounds have different industrial and commercial applications. Otherwise, are widely applied in the leather industry, as well as beverages additives, corrosion inhibitors of metals in shipbuilding, wood adhesives, and foams [13]

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