Profile of Polyphenolic and Essential Oil Composition of Polish Propolis, Black Poplar and Aspens Buds

Abstract

In this work, we studied similarities and differences between 70% ethanol in water extract (70EE) and essential oils (EOs) obtained from propolis, black poplars (Populus nigra L.) and aspens (P. tremula L.) to ascertain which of these is a better indicator of the plant species used by bees to collect propolis precursors. Composition of 70EE was analyzed by UPLC-PDA-MS, while GC-MS was used to research the EOs. Principal component analyses (PCA) and calculations of Spearman’s coefficient rank were used for statistical analysis. Statistical analysis exhibited correlation between chemical compositions of propolis and Populus buds’ 70EE. In the case of EOs, results were less clear. Compositions of black poplars, aspens EOs and propolises have shown more variability than 70EE. Different factors such as higher instability of EOs compared to 70EE, different degradation pattern of benzyl esters to benzoic acid, differences in plant metabolism and bees’ preferences may be responsible for these phenomena. Our research has therefore shown that 70EE of propolis reflected the composition of P. nigra or complex aspen–black poplar origin.

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

“…Isomers δ-, γand α-cadinene were typical for RP HS and EO that can be also connected with P. nigra (cadinene chemotype) distribution on the island Rab. P. nigra buds EO was reported also with different profiles containing a mix of sesquiterpenes and derivates of benzoic acid, mainly prenyl benzoate [60]. About 50% of the GC chromatograms of hexane extracts of P. nigra buds [62] consisted of higher alkanes including docosane and tricosane (found in RP, PP, K1P, K2P and K3P EO), but C 25 -C 31 alkanes dominated (they were not present in investigated propolis EO probably due to lower volatility).…”

“…Black poplar (P. nigra) buds exhibited different EO profiles (both qualitatively and quantitatively). Some buds contained mainly oxygenated sesquiterpenes, particularly α-, βand γ-eudesmols that are present in P. nigra buds EO [60,61] as well as their CO 2 extracts [20]. These compounds are present in K1P, K2P and K3P EO, PP HS and EO as well as RP HS and EO that could be connected with the P. nigra (eudesmol chemotype) distribution on the islands Krk, Rab and Pag.…”

“…Isomers guaiol and bulnesol were characteristic for PP HS and EO as well as RP EO indicating dominant influence of P. nigra (bulnesol/guaiol chemotype) from the islands Pag and Rab. Several P. nigra buds EO [60] were mainly composed of sesquiterpene hydrocarbons (mainly ar-and γ-curcumene and δ-cadinene). Isomers δ-, γand α-cadinene were typical for RP HS and EO that can be also connected with P. nigra (cadinene chemotype) distribution on the island Rab.…”

“…Aspen buds (P. tremula) also exhibited different EO profiles. Several aspen buds [60] contained mostly benzoic acid derivates (benzyl benzoate, salicyl benzoate and trans-benzyl cinnamate). They were identified in K2P EO indicating aspen (P. tremula)-type propolis and P. tremula is reported on the island Krk [36].…”

“…All the samples contained at least traces of prenyl caffeates, recognized as typical for the most common European black poplar-type propolis [60], however their total amount was more relevant only in three samples RP, K1P and K3P (37.74, 11.49, 5.92 mg/g, respectively), demonstrating primary (RP) or secondary (K1P and K3P) contribution of P. nigra balsam in those specimens ( Table 4). The same samples contained also another typical compounds from this source, such as pinobanksin 3-O-acetate, chrysin, pinocembrin and others [60] which again were very abundant in RP. RP contained particularly high amount of isoferulic acid (8.30 mg/g), while K1P and K3P only its slightly elevated amount (0.67-0.80 mg/g); though the amount of isoferulic acid was 2-4 times higher than of ferulic acid, which suggests that the bud exudate was partially collected from P. nigra var.…”