Chemical Characterisation, Antioxidant and Antibacterial Activities of Pinus pinaster Ait. and Pinus pinea L. Bark Polar Extracts: Prospecting Forestry By-Products as Renewable Sources of Bioactive Compounds

Sónia A O Santos,Rodrigo T Neto,Carla Pereira,Artur M S Silva,Adelaide Almeida,Armando J D Silvestre,Ana Peixoto Gomes,Patrícia A B Ramos

doi:10.3390/app12020784

Abstract

Agroforestry by-products have gained rising attention in recent years as they represent inexpensive and abundant raw materials that are a source of added-value chemicals, e.g., for food and pharmaceutical applications, as well as for bioenergy generation. Pinus pinaster Ait. bark extracts are consumed worldwide for their cardiovascular benefits, whilst the health potential of Pinus pinea L. bark has not yet been deeply exploited. Therefore, this study highlights the chemical characterisation of Portuguese P. pinaster Ait. and P. pinea L. bark polar extracts, via ultra-high performance liquid chromatography-diode array detection-tandem mass spectrometry (UHPLC-DAD-MSn) analysis, and their antioxidant and antibacterial activities. Quinic acid, an A-type procyanidin dimer isomer, protocatechuic acid, and quercetin were identified for the first time as P. pinea L. bark components. Moreover, this bark demonstrated a higher total content of identified polar compounds than P. pinaster Ait. bark, with quinic acid being the most abundant compound identified. Regarding antioxidant activity, the pine bark polar extracts exhibited strong reducing power and 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azinobis-(3-ethyl-benzothiazoline-6-sulfonic acid (ABTS) radical scavenging effects compared to natural antioxidants. Moreover, the bactericidal actions of pine bark extracts were shown against Staphylococcus aureus and Escherichia coli at a 3.13–25 mg mL−1 range. Globally, these promising insights can boost the sustainable exploitation of P. pinea L. bark, as already occurs with P. pinaster Ait. bark, for the food and biomedical fields.

Highlights

In the scope of the 2030 Agenda for Sustainable Development, countries and stakeholders are committed to contributing to society and to world prosperity, tackling economic, social, and environmental challenges [1]
The Portuguese pine forest mainly consists of Pinus pinaster Ait. and P. pinea L., which, in 2015, accounted for ca. 7.1 × 105 and 1.9 × 105 ha of the continental soil, respectively [3]
Gallic acid (≥97.5%), Folin–Ciocalteu’s phenol reagent (2 N), HPLC-grade water, formic acid (≥98%), protocatechuic acid (>97%), catechin hydrate (>99%), quercetin (>98%), taxifolin (≥85%), 2,2-diphenyl-1-picrylhydrazyl radical (DPPH ), 2,2-azinobis-(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) diammonium salt, ascorbic acid (≥99.5%), and (±)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (97%) were supplied by Sigma-Aldrich

Summary

Introduction

In the scope of the 2030 Agenda for Sustainable Development, countries and stakeholders are committed to contributing to society and to world prosperity, tackling economic, social, and environmental challenges [1]. Represents the second major tree family in Portuguese forests 9.6 × 105 ha of continental soil), after the Quercus spp. family. 7.1 × 105 and 1.9 × 105 ha of the continental soil, respectively [3]. The Portuguese pine forest mainly consists of Pinus pinaster Ait. and P. pinea L., which, in 2015, accounted for ca. Given their good adaptation to edaphoclimatic conditions, notably frost resistance, adaptation to summer drought, and tolerance to poor soils, P. pinaster Ait. has been planted for coastal sand dunes stabilisation, soil conservation, and agricultural culture protection against salt spray

Methods

Results

Conclusion