Mediterranean Propolis from the Adriatic Sea Islands as a Source of Natural Antioxidants: Comprehensive Chemical Biodiversity Determined by GC-MS, FTIR-ATR, UHPLC-DAD-QqTOF-MS, DPPH and FRAP Assay

Abstract

There is no systematic report about propolis chemical biodiversity from the Adriatic Sea islands affecting its antioxidant capacity. Therefore, the samples from the islands Krk, Rab, Pag, Biševo and Korčula were collected. Comprehensive methods were used to unlock their chemical biodiversity: headspace solid-phase microextraction (HS-SPME) and hydrodistillation (HD) followed by gas chromatography and mass spectrometry (GC-MS); Fourier transform mid-infrared spectroscopy (FT-MIR); ultra high performance liquid chromatography with diode array detector and quadrupole time-of-flight mass spectrometry (UHPLC-DAD-QqTOF-MS) and DPPH and FRAP assay. The volatiles variability enabled differentiation of the samples in 2 groups of Mediterranean propolis: non-poplar type (dominated by α-pinene) and polar type (characterized by cadinane type sesquiterpenes). Spectral variations (FT-MIR) associated with phenolics and other balsam-related components were significant among the samples. The UHPLC profiles allowed to track compounds related to the different botanical sources such as poplar (pinobanksin esters, esters and glycerides of phenolic acids, including prenyl derivatives), coniferous trees (labdane, abietane diterpenes) and Cistus spp. (clerodane and labdane diterpenes, methylated myricetin derivatives). The antioxidant potential determined by DPPH ranged 2.6–81.6 mg GAE/g and in FRAP assay 0.1–0.8 mmol Fe2+/g. The highest activity was observed for the samples of Populus spp. origin. The antioxidant potential and phenolic/flavonoid content was positively, significantly correlated.

Red Propolis and Its Dyslipidemic Regulator Formononetin: Evaluation of Antioxidant Activity and Gastroprotective Effects in Rat Model of Gastric Ulcer

“…However, several studies have shown that natural products with antioxidant activity protect gastric mucosa against damage [ 60 , 61 , 62 , 63 ]. The advantages of HERP for human use have been extensively discussed in the literature, relying on the many identified beneficial effects, mostly attributed to its antioxidant properties [ 5 , 64 , 65 , 66 , 67 ]. Various phenolic antioxidants, such as flavonoids, coumarins, tannins, procyanidins, and xanthenes, act as radical scavengers, neutralizing ROS, inhibiting lipid peroxidation and other free radical-mediated pathologies, in a dose-dependent fashion.…”

Plant Sources Responsible for the Chemical Composition and Main Bioactive Properties of Poplar-Type Propolis

“…The most recent study on propolis phenolics and volatiles [ 98 ] used ultrahigh-performance liquid chromatography with diode array detector and quadrupole time-of-flight mass spectrometry (UHPLC-DAD-QqTOF-MS), and identified a high number of compounds (118 phenolics), suggesting that equipment and methods that are more elaborate and up-to-date can identify and quantify more compounds.…”

Valorization of Gleditsia triacanthos Invasive Plant Cellulose Microfibers and Phenolic Compounds for Obtaining Multi-Functional Wound Dressings with Antimicrobial and Antioxidant Properties

“…The main phenolic compounds identified in the alcoholic extract of G. triachantos were vanillic acid (773.88 µg/L), 4-hydroxy benzoic acid (570.37 µg/L), ferulic acid (319.81 µg/L), catechin (34,271.15 µg/L), quercetin (3,007.89 µg/L), and epicatechin (1,431.47 µg/L). The extract was rich in chlorogenic acid (11,984.43 µg/L), cinnamic acid (2,736.42 µg/L, an acid that lacks phenolic groups but is still usually included in the phenolic compounds class), and rutin (1,302.31 µg/L). The following compounds were also evidenced by UHPLC-DAD-ESI/MS: abscisic acid (16.10 µg/L), a sesquiterpenoid plant hormone, and ellagic acid (165.13 µg/L), a dimer of gallic acid.…”

“…G. triachantos pods were ground into powder (to pass through a 100 mesh sieve) with a structure characterized by ATR-FTIR (Attenuated Total Reflectance-Fourier Transform Infrared) to highlight the specific bands of the three major components (see Section 2.3.1), which are hemi-cellulose (39.07% ± 1.49%), cellulose (29.78% ± 1.28%), and lignin (27.71% ± 0.75%) [11]. Then, the wood powder was subjected to purification by successive extractions to remove the extractable substances, hemicellulose (toluene and ethanol), and lignin.…”