Metabolomics study of Populus type propolis

Abstract

Herein, we propose rapid and simple spectroscopic methods to determine the chemical composition of propolis derived from various Populus species using a metabolomics approach. In order to correlate variability in Populus type propolis composition with the altitude of its collection, NMR, IR, and UV spectroscopy followed by OPLS was conducted. The botanical origin of propolis was established by comparing propolis spectral data to those of buds of various Populus species. An O2PLS method was utilized to integrate two blocks of data. According to OPLS and O2PLS, the major compounds in propolis samples, collected from temperate continental climate above 500m, were phenolic glycerides originating from P. tremula buds. Flavonoids were predominant in propolis samples collected below 400m, originating from P. nigra and P. x euramericana buds. Samples collected at 400-500m were of mixed origin, with variable amounts of all detected metabolites.

Effectiveness of Different Analytical Methods for the Characterization of Propolis: A Case of Study in Northern Italy

“…Specific resonances attributable to glycerol esters (such as 1,3-di-p-coumaryl-2-acetyl-glycerol and 1,3-diferulyl-p-coumarate-glycerol) were given by the presence of signals in the zone 4.2-5.3 ppm (glycerol moiety), an area crowded with several overlapping signals, and a singlet resonance for methyl groups at 2.05 ppm. The presence of the acetyl groups and the ester groups were also confirmed by 13 C-NMR spectrum due to the presence of signals in the area between 160 and 170 ppm, the portion of glycerol, instead, gives signals at 63-71 ppm, the methyl groups of acetyl at 19.7 and 21.9 ppm in agreement with the literature data ( Figure 4) [25]. The definition of the type of glycerol ester was given with LC-MS orbitrap.…”

“…The total flavones and flavonols (TFF) were estimated according to an aluminum chloride method following [63]. For the calibration curve, four standard solutions of quercetin in 80% ethanol (25,50,100, and 200 µg/mL) were prepared (y = 0.0099x -0.055; R 2 = 0.9999). A 0.5 mL portion of standard solutions was separately mixed with 1.5 mL of 95% ethanol, 0.1 mL of 10% AlCl 3 in water (w/v), 0.1 mL of 1 M potassium-acetate, and 2.8 mL of 80% ethanol.…”

“…Advanced techniques as HPLC-high resolution mass spectrometry (HRMS) accompanied with a metabolomic approach could be a sufficiently descriptive method as it is able to detect the biomarkers that could be used as indicators of authentication. For the in-depth characterization of propolis recently developed analytical platforms based on NMR technique has been proved suitable for defining some a whole series of isomeric compounds found in propolis [25].…”

Insight on Propolis from Mediterranean Countries: Chemical Composition, Biological Activities and Application Fields

“…It was found that the main flavonoids found were pinocembrin (3), pinobanksin (1), pinobanksin-3-O-acetate (4), chrysin (2), quercetin (26), kaempferol (25) pinocembrin-7-methyl ether (27) and galangin (9) (Figure 1), while benzoic (28), ferulic (7), caffeic (5), 3,4-dimethoxycinnamic (29), cinnamic (21) acids were the most abundant phenolic acids. [54][55][56][57][58][59][60][61][62][63][64] However, other authors demonstrated that Croatian propolis contain phenolic acid esters such as CAPE (8), benzyl caffeate (12), benzyl coumarate (30) and cinnamic acid esters. [64 -66] On the another hand, Sobočanec et al [67] have reported the presence of flavonoids only in propolis samples from Continental Croatia.…”

Microwave Ultrasound Assisted Extraction: Determination of Quercetin for Antibacterial and Antioxidant Activities of Iranian Propolis

“…Maceration was adapted, the method was described by Anđelković, et al [22]. About 1 g of propolis powdered was cooled at -20 ° C, then materials were placed in a Erlenmeyer flask, 10 ml solvent (methanol: water, 80:20) was added.…”