Diversity of wormwood (Artemisia absinthium L.) growing wild in Poland in respect of the content and composition of essential oil and phenolic compounds

Wormwood herb is regarded as a medicinal raw material rich in bitter principles. However, its biological activity is also affected by the presence of essential oil and phenolic compounds. In Poland wormwood herb is collected mainly from wild growing plants. The aim of the study was to compare the content and composition of essential oil and phenolic compounds in the raw materials obtained from 18 populations of wormwood from the central and north-eastern area of Poland. Herb was collected at the stage of plant blooming and dried naturally. Content of essential oil in the raw materials was determined by hydrodistillation method, and its composition by GC. Methanolic extracts obtained by continuous exhaustive extraction of raw materials were used for qualitative and quantitative analysis of phenolic compounds by HPLC. The content of essential oil in the investigated raw materials ranged from 0.40 to 0.88%. In 6 populations the dominant constituent of essential oil was sabinyl acetate, in three - chrysanthenyl acetate, in two - sabinene, and in one - β-thujone. Other populations were characterised by comparable content of two or three main compounds in essential oil, e.g., sabinene and β-myrcene, β-myrcene and cineol, chrysanthenyl acetate and β-myrcene, sabinyl acetate, chrysanthenyl acetate and β-thujone. In the investigated raw materials 11 phenolic substances were identified: 5 phenolic acids (caffeic, p-coumaric, ferulic, chlorogenic, and rosmarinic one), 5 flavonoids (apigenin, diosmetin, orientin, quercetin, and hyperoside), and (-)-epigallocatechin gallate. In the raw materials obtained from all the investigated populations the dominant phenolic compound was ferulic acid but its content was diverse (396-1118 mg 100 g-1 of dry herb). A remarkable amount of chlorogenic and rosmarinic acids was also found (159-477 and 178-446 mg 100 g-1, respectively).