Effect of Harvesting Time and Plant Age on some Quality Parameters of Lovage (Levisticum officinale KOCH.)

Lovage (Levisticum officinale KOCH.) is well known as a spice in the culinary and food industry and its pharmacological effect is utilised too. As a member of the Apiaceae family, it accumulates essential oil in each organ, which basically determines the quality of the drugs. Investigations were carried to study the role of harvesting time and age of the plants on the accumulation dynamics and main components of the volatile oil as well as on the sensory quality of the leaves and roots. Following the usual cultivation practices, leaf samples were taken in ten day intervals from the middle of July through the beginning of November and root samples from the beginning of September until the end of October both in one-yearold and two-year old populations. We have established in harmony with the literature data that both the age and harvesting date influenced the essential oil content of the drugs. The two-yearold leaves and roots contained higher essential oil content than the one-year-old samples. During vegetative stages, the highest volatile oil contents in the leaves were found in the middle of August, while in the roots in the second half of October. The sensory characteristics of the examined samples however, showed no connection with their harvesting time and plant age. INTRODUCTION Lovage (Levisticum officinale KOCH.) is well known both as a spice in culinary and food-industry as well as an effective phytotherapeutic agent, possessing strong diuretic effect. The plant accumulates essential oil in each of its organs as the characteristic active agent of the Apiaceae family. Quality of crude drugs of lovage is usually evaluated according to their sensory characteristics and the essential oil properties. However, hardly any scientific data has been published on different factors, which influence these parameters. Therefore, our investigations were focused on determining the role of some biological (plant organ, age of the plant) and technological (harvesting time) factors on crude drug quality. MATERIALS AND METHODS Plant Material The experimental populations were grown under open field conditions at the Experimental Station of the Faculty of Horticultural Sciences in Budapest. We investigated oneand two-year-old populations of Levisticum officinale KOCH. of unknown origin from our gene-bank collection. Average leaf samples were collected in ten day intervals from the middle of July through the beginning of November. Root samples were taken in autumn three times in monthly intervals from the beginning of September until the end of October. Chemical Analysis Essential oil contents both of fresh materials and the dried drugs were determined by hydrodistillation in Clevenger-apparatus according the method of Ph.Hg. VII. The Proc. Int. Conf. on MAP Eds. J. Bernáth et al. Acta Hort. 576, ISHS 2002 312 main components of the oil were analysed by capillary gas-chromatography method (Shimadzu GC-B14 with Shimadzu Class – VP Chromatography Data System 4.2 equipped with FID) and the components identified by peak-addition with standards. Sensory Analysis Sensory analysis of dried leaf samples (profile analysis, a descriptive method) was done in the Sensory Laboratory of our University by student groups. Two of the samples of both of one-year-old (harvested in August /18.08./ and September /27.09./) and twoyear-old populations (harvested in July /24.07./ and October /12.10./) were examined, respectively. RESULTS AND DISCUSSION The amount of the volatile oil in two-year-old leaves was higher both in fresh and dry mass than the essential oil content of one-year-old leaves, with the exception of two harvesting dates (Fig. 1). However, the difference is more pronounced in the fresh samples. Similar results were detected in the roots (Fig. 2). During the vegetation period, the highest values were found in the crude drugs, when harvested in the middle of August, except in case of one-year-old dry samples, when the maximum essential oil content was found in the beginning of September. The one-year-old stands produced 1.84 % d.w. in the fresh leaves and 1.72 % d.w. essential oil in dry leaves (Fig. 1). In the two-year-old population, the peaks are higher, 2.78 % d.w. in the fresh leaves and 2.22% d.w. in the dry leaves samples (Fig, 1). In the roots, a later accumulation maximum was found among the analysed one-year-old samples in the second half of October. The detected main components of the essential oil are summarised in Table 2. βphellandrene and l-p-menthyl-8-yl-acetate were found in the leaves while alkyl-phtalide was identified in the root samples. The proportions of the components did not show any significant dependence ob the experimental factors. During the sensory analysis, four sensory features of the leaves were found to be of distinguishing value: intensity of the green colour, presence of brownish colour, celerylike odour and pungent odour (Fig. 3). The one-year-old population harvested in September showed the significantly most intensive green colour and the two-year-old population harvested in October had the weakest green colour, instead, turning a brownish colour. The celery-like odour, which is a very important characteristics of lovage, was significantly the most intensive in case of the one-year-old sample harvested in August. The difference of the pungent odour between harvesting times of the two-yearold populations seems to be significant, while it is not the case between samples of oneyear-old populations. Our results proved the significant effect of the age of the plantation and the role of the sampled plant organ to the oil accumulation, which is in harmony with former findings (Szebeni-Galambosi and Galambosi, 1992, Seidler-Lozykowska and Kazmierczak, 1998) (Table 1). In the most harvesting dates the two-year-old populations exhibited significantly higher contents of essential oil both in leaf and root samples than the one-year -old ones. Compared to literature data, these values in leaves can be evaluated as especially high. The essential oil content of root samples are however lower than recorded in literature. CONCLUSION The harvesting time showed to have a significant effect on the essential oil accumulation both of leaves and roots. The established maximum values may help in technology development, although checking the interactions with genotype, vegetation year and weather conditions needs further trials. The sensory characteristics of the examined samples showed significant differences, however, there was no connection with their harvesting time and plant age.