Effect of genotype and age on essential oil and total phenolics in hyssop (Hyssopus officinalis L.)

Five Hyssopus officinalis L. accessions (German, Hungarian and Polish ones) were compared over three years with regard to their development and secondary metabolite production, in an open field experiment. The Hungarian variety ‘Sophie’ produced the highest essential oil (EO) yield (up to 2.037 ml/100 g). In general, one-year old individuals accumulated the most volatile organic compounds (VOCs) and the accumulation was influenced significantly by genotype and year. A total of 47 components were identified in all of the oils. In all accessions cis- and transpinocamphones were most frequently the major compounds, but there were quantitative differences among genotypes. Highest proportions of these two components together appeared in ‘Erfurter Ysop’ (70.7%). The third main compound was β-pinene that accumulated in the Hungarian accessions in the highest proportions (11-19%). The cultivation year did not have a considerable influence on the EO composition. Significant difference in the total phenolic content was evident among genotypes, and ranged from 443.64 mg/g DW (‘Erfurter Ysop’) and 329.32 mg/g DW (‘Hyzop lekarsky’) calculated as gallic acid. The effect of the year was not significant, although we detected a significant variety × year interaction. In general, the selected hyssop cultivars showed an advance to commercial batches.