Ontogenetic variation of active agent content of yarrow (Achillea collina Becker)

Abstract

The effect of harvesting time on the drug quality of yarrow was examined in open field experiment between 2012–2014 using the variety Achillea collina 'Proa'. Sampling of the plants were carried out in five phenological phases during flower development (BBCH 55–69). Essential oil content, proazulene content, total flavonoid and total phenolic content of the dried shoots were measured. Additionally, the ratio of plant organs in each phenophase was determined.We established that the proportion of useful plant parts (flowers and leaves) in the drug increases from 56.33–59.83% (budding stage) to 65.17–73.07% (overblooming phase). The changes of chemical characteristics, however, followed these tendencies just partially. A peak accumulation level of essential oil (0.230–0.334mg/100g) was reached in white bud stage, after that the oil content decreased. The highest content of proazulene (0.123–0.183%) was measured in the same phenological phase. The flavonoid content of yarrow during flowering is presumably more variable than the content of other active compounds; it reached its maximum (0.900–2.837%) in green bud—early flowering phase while the total phenolic content showed two peaks: in green bud stage (178.0–233.4mgGAE/g) and in overblown phenophase (170.9–258.5mgGAE/g). Considerable year effect was detected in the case of each measured parameter. Based on the results, optimal drug quality could be achieved by harvesting yarrow in the first half of flowering (BBCH 61–65).