# Phenolic Compounds in Trees and Shrubs of Central Europe
## 3 Results
### Phenolic Compounds
#### 3.1.1. Phenolic Acids
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Trees and Shrubs** & **Phenolic Acids** & **Literature** \\ \hline \hline \multirow{2}{*}{Scots pine _Pinus sylvestris_ L.} & Caffeic acid, salicylic, ferulic, vanillic, gallic, & [52; 53; 54; 55; 56; 57] \\  & sinapic, \(p\)-coumaric, protocatechuric acids & \\ \hline \multirow{2}{*}{Norway spruce _Pica abies_ H. Karst in the roots, wood, mature seeds} & Shikimic acid, galusic acid, \(p\)-coumaric acid, & \\  & photocatechuric acid, ferulic, vanillic, syringic, & \\  & sinapic, salicylic, quintic acids, protocatechuric, & \\  & gallic acids & \\ \hline \multirow{2}{*}{Silver fir Abies alba Mill. Wood and bark} & Gallic acid, homovananillic acid protocatechuric acid, p-hydroxybenzoicic acid, vanillic and & [63] \\  & & \(p\)-coumaric acids & \\ \hline \multirow{2}{*}{European beech _Fagus sylvatica_ L-leaves} & Caffeic acid, ferulic acid, chlorogenic acid & \\  & syringe, gallic, abscisic and cinnamic acids & [52; 58; 64] \\ \hline \multirow{2}{*}{Oak _Quercus robus_ L.} & Ellagic acid, gallic acid, gentisic acid, & \\  & \(p\)-hydroxybenzoic acid, protocatechuric acid & \\  & syringe acid vanillic acid, \(p\)-coumaric acid, & \\  & caffeic acid, ferulic acid sinapic acid & \\ \hline \multirow{2}{*}{Walnut _Juglans regia_ L.} & Ellagic acid, caffeic acid, \(p\)-coumaric acid, & \\  & galvanic acid & \\ \hline \multirow{2}{*}{Willow _Salix_ spp.} & Ferulic, caffeic, salicylic, vanillic, syringic, & \\  & \(\alpha\)-resacrylic, m and \(p\)-hydroxybenzoicic, & [58; 69] \\  & \(p\)-coumaric, cinnamic acids & \\ \hline \multirow{2}{*}{_Salix alba_ L.} & Salicylic and \(p\)-coumaric acid & [70] \\ \hline \multirow{2}{*}{_Salix babylonica_ L-leaves} & Caffeic and \(p\)-coumaric acids & [71] \\ \hline \multirow{2}{*}{_Salix capitata_ L-leaves} & Protocatechuric acid & [72; 73] \\ \hline \multirow{2}{*}{Silver birch _Betula pendula_ Roth-leaves} & Chlorogenic, \(p\)-hydroxybenzoicic, caffeic, gallic, & \\  & coumaric, \(p\)-hydroxycinnamic acids & [74] \\ \hline \multirow{2}{*}{Hawthorn _Cntagus_ L.} & Chlorogenic, caffeic acid & [58; 75] \\ \hline \multirow{2}{*}{Rowan _Sorbus aucuparia_ L.} & Neochlorogenic, chlorogenic, protocatechuric, & \\  & caffeic and \(p\)-hydroxybenzoic acids & [76] \\ \hline \multirow{2}{*}{_White poplar Populus alba_ L-buds} & Benzoic, ferulic, caffeic acids, cinnamic, & \\  & cis-\(p\)-coumaric and trans-\(p\)-coumaric acids & [58; 77] \\ \hline \multirow{2}{*}{Bird cherry _Prunus padus_ L. fruits} & Caffeic acid, ferulic, coumaric, chlorogenic, & \\  & pelagic, gallic acids & [58; 78] \\ \hline \multirow{2}{*}{Prunus serotina Ehrh.} & Gallic acid, caffeic and \(p\)-hydroxybenzoicic & [79] \\  & acids, \(p\)-coumaric, ferulic, cinnamic acids & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Phenolic acids found in trees and shrubs. concentration in the needles tested. Salicylic acid and rozmaric acid, on the other hand, were present at a very low concentrations in all tested samples, except for larch for the latter acid. The samples varied considerably in terms of the content of phenolic acids (Table 3). Elderberry, bird cherry and dogwood fruits and dogwood leaves were characterised by high phenolic acid content, and the samples were particularly rich in benzoic acid (especially dogwood), \(p\)-coumaric acid and chlorogenic acid. The highest variation was found in the case of benzoic acid, where, in the dogwood fruit sample, it was present in concentrations of 655 \(\upmu\)g/g d.w. and 17 \(\upmu\)g/g d.w. for bird cherry bark. Protocatechuic, 4-hydroxybenzoic, vanillic, caffeic, salicylic and rozmaric acids were present in low concentrations in almost all samples (Table 4).