In our work the effectiveness of supercritical carbon dioxide extraction was studied on volatile components of Lamiaceae herbs. The aim of our investigations was to determine the optimal extraction parameters yielding high amount of volatiles in a desirable composition. As plant materials, dried and powdered cude drugs of Thymus vulgaris, Thymus pannonicus, Satureja hortensis, Ocimum basilicum, Rosmarinus officnalis and Salvia officinalis were chosen. Pressure (8-30 MPa), temperature (35-60 °C) and time (5-60 min) of extraction were regulated. Results obtained by supercritical fluid extraction (SFE) were compared to that of the conventional extraction procedur, hydrodistillation (HD). In the case of Thymus vulgaris, Thymus pannonicus and Salvia officnalis, extract yield of SFE was comparable to the essential oil amount obtained by hydrodistillation from the same drug. Essential oil rich thyme extracts were analysed by GC-FID. We have found that yield and quality of SFE extracts highly depend on the conditions of extraction.
Several species in the Lamiaceae family are therapeutically significant medicinal plants. Such as sage (Salvia officinalis L.), rosemary (Rosmarinus officinalis L.), peppermint (Moldier piperita L.). marjoram (Majomna hortensis Winch), thyme (Thymus vulgaris L.), Origanum spp., hyssop (Hyssopus officinalis L.), Lavandula spp., basil (Ocimum basalicum L.), lemon-balm (Melissa officinalis L.) are regularly produced in Hungary. Nevertheless, data on their floral biology are not satisfactory. This review intends to gather information on the characteristic constitution of flowers and inflorescences, blooming dynamics, pollination mechanism and crossability of some of the most significant medicinal and spice species
Flowers are mainly hermaphrodite, however, also monoeceous ones are turning up: pistillate flowers marjoram, tyme, oregano. In flowering of a plant individual, a basipetal blooming sequence is described. These species have a floral structure fully adapted to pollination by insects, and the majority of them is an excellent honey-plant (lavandel, hyssop, sage, etc.).
Flowers exhibit characteristic proterandry, therefore autogamy is considered to be almost impossible, and geintonogamy as well as xenogamy to be the most characteristic ways of fertilization. However, in several cases self-fertilization proved to be also successful. Crossability among cultivars or species is depending on the genotype combination and usually produces less seed than the above forms of fertilization.
In our work the effectiveness of supercritical carbon dioxide extraction was studied on volatile and nonvolatile components of Lamiaceae herbs. The aim of our investigations was to determine the optimal extraction parameters yielding high amount of volatiles and nonvolatiles in a desirable composition. As plant materials, dried and powdered cude drugs of Satureja hortensis, Ocimum basilicum and Melissa officinalis were chosen. Pressure (8-50 MPa), temperature (35-60 °C), time (5-60 min) and the ratio of modifier (5-50% methanol) of extraction were regulated. Results obtained by supercritical fluid extraction (SFE) were compared to that of the conventional extraction procedure, hydrodistillation (HD). In the case of Satureja hortensis, Ocimum basilicum and Melissa officinalis extract yield of SFE was comparable to the essential oil amount obtained by hydrodistillation from the same drug. Essential oil rich extracts were analysed by GC-FID, while extracts rich in nonvolatile compounds were analysed by HPLC. We have found that yield and quality of SFE extracts highly depend on the conditions of extraction.
Growing of native perennial species became more and more popular in the last ten years. In order to obtain more information on their histological structure, investigations were done on Aster linosyris, Inula ensifolia and Prunella grandiflora. The histological features are usually relating to the plants' ecological demands which is an important aspect in their growing. Differences were found in the structure of the stem of Asteraceae and Lamiaceae members. While separated vessels were formed in the stem of Aster linosyris and Inula ensifolia, continuous vessel-system forms in the stem of Prunella. Alternating segments of collenchyma and chlorenchyma are found in the stem of Aster linosyris, while palisade parenchyma is situated both on the abaxial and adaxial surface of the leaves. Vessel-system of the root is tetrarch. Histological structure of the stem of Inula ensifolia differs from Aster linosyris in the broader cortical parenchyma which is composed of approx. 8-12 cell layers. It contains neither collenchyma nor chlorenchyma. In the stem of Prunella grandiflora a nearly continuous vessel-ring is formed from the four primary vessels. Long, multi-celled hairs were observed in the district of angles of the stem.
Authors dealt more than ten years with the analysis of supercritical extracts. For extraction (SFE) carbon dioxide was used as supercritical solvent. Fractionation of extracts was carried out by releasing the separations pressure at two stages. The extracts were collected as separate samples successively in time.
The traditional extractions were carried out with steam distillation or by using n-hexane and ethanol in Soxhlet apparatus. For the analysis of volatile compounds GC, GC-MS; of non volatile compounds TLC-densitometry and spectroscopic methods were used.
The following general characteristics were established comparing the composition of steam distillated oils with that of volatile SFE fractions. The SFE fractions were richer in monoterpene-esters and poorer in alcohols than the essential oils prepared by traditional way (clary sage, lavandel). Regarding the distributi,n of the monoterpene and sesquiterpene compounds, the SFE fractions contained sesquiterpene hydrocarbon in higher percentage than the distillated oils (e.g. 13-caryophyllene in Salvia fruticosa, (3-caryophyllene, ymuurolene, y-cadinene in Ochnum basilicum). Further the proportion of sesquiterpenes increased in SFE fractions collected successively in time.Significant difference was remarkable in respect of the optical rotationability of lovage oil and SFE fraction which was probably caused by the different ratio between the two ligustilid enantiomers. It was verified in some cases that a part of mono- and sesquiterpenes were present originally in a bounded form (glycosides) in plants. Therefore they appeared in essential oil fractions only after previous acidic treatment (Thymus, Origanum species). During the supercritical extraction the azulenogene sesquiterpene lactones did not transform to azulenes (in chamomile, yarrow), but the non volatile SFE fractions of some Asteraceae plant contained sesquiterpene--lacton of unchanged structure in high quantity (e.g. cnicin in blessed thistle, parthenolide in feverfew). Authors obtained also SFE fractions which were rich in triterpenoids and phytosterols (marigold, common dandelion).
The influence of nitrogen-fertilizer applied in 0, 50, 100 and 150 kg/ha dosages, as well as the time of the harvest carried out in full flowering and early fruit set stages were studied on the herb and essential oil production of garden thyme (Thymus vulgaris L.). The small plot experiment was installed in the Experimental Field of Tarbiat Modarres University near Teheran, under sandy loam soil conditions. On the basis of the results the nitrogen-fertilizer had a significant effect on the dry-matter production of the species: the herb yield, calculated on one hectare, increased from 671.88 kg up to 1021.00 kg value as a result of 150 kg nitrogen dosage. The essential oil yield proved to have a similar tendency because neither the accumulation level of essential oil, nor the ratio of thymol were effected by the nutrient supply. Analyzing the effect of harvest time changes in both dry-mass production and essential oil accumulation were observed. The highest herb yield (1238.20 kg/hectare) was obtained in early fruit set, when about.50 per cent of fruits reached their full size in the inflorescence. The accumulation level of essential oil also reached its maximum at the sane development stage, showing 0.75 per cent value, which is about two fold higher comparing to the accumulation level was measured at the time of full flowering (0.41 %).