SEASONAL-VARIATION OF THE ESSENTIAL OIL, VALERENIC ACID AND DERIVATIVES, AND VALEPOTRIATES IN VALERIANA-OFFICINALIS ROOTS AND RHIZOMES, ANDTHE SELECTION OF PLANTS SUITABLE FOR PHYTOMEDICINES

During the seasons 1989-1993, Voleriana officinalis plants were invest igated for their contents of essential oil, valerenic acid and derivat ives, and valepotriates. Harvesting of the subterranean parts was star ted in August of the year in which the seeds were sown, and continued until the last week of April of the subsequent year. Despite marked va riations from year to year, the maximum contents of essential oil in t he subterranean parts of V. officinalis were found in September, rangi ng from 1.2% to 2.1% (v/w) based on dry weight (DW). Over the vegetati on periods investigated, the composition of the oil remained more or l ess constant. Valerenic acid and its derivatives, and the valepotriate s reached their maxima in February-March, with contents of 0.7-0.9 % ( DW) and 1.1-1.4% (DW), respectively. During the period 1989-1993, five V. officinalis strains were investigated for their contents of essent ial oil, valerenic acid and derivatives, and valepotriates in order to select plants suitable for phytomedicines. The selection procedures d escribed in this paper finally yielded plant material (in 1993) with a satisfactory content of essential oil (0.9%) combined with a high con tent of valerenic acid and derivatives (0.5%) which can be harvested i n September of the year of sowing.