Sideritis scardica Griseb. is a threatend medicinal plant, an endemic of Balkan peninsula. It is included in The Red Book in Bulgaria and protected by the National Protected Low. The collection and trade from nature are prohibited. A study on the cultivation of species is reported.

Following the three stages of investigations: studies on ecological and biological peculiarities of fore populations; factors determining the optimal development of the drug, and the growth of the species under cultivation conditions, authors recommend the breeding of the species in production areas. It is expected to produce about 150 kg/dka dry standardized drug during the 3-year of vegetation and over 300 kg/dka between the 4- and 8-years.

The genus Sideritis (Lamiaceae) comprises about 140 species distributed mainly in the Mediterranean regions and in the moderate zones of Asia. The taxa are attributed to three sections: sect. Sideritis, sect. Empedoclia (Rafin.) Bentham. and sect. Hesiodora Bentham. The species occur in Bulgaria, belonging to sect. Empedoclia: S. scardica Griseb. and S. syriaca L. (S. taurica Steph. Ex Wild) and sect. Hesiodora: S. montana L. and S. lanata L. S. scardica is a perennial plant with a woody base, endemic for the Balkan peninsula (Stojanov et al., 1967, Heywood, 1972; Papanicolaou and Kokkini, 1982; Asenov, 1989). Griesebach (1844) was the first, who described this taxon of a Macedonian origin. Later, the species was found also in other localities in southwest Albania, Greece and Bulgaria.

In Bulgaria the species is known under the name "Pirin mountain tea" or "Mursalitza tea" and occurs in the mountains Pirin, Slavjanka and the Rhodopes from 1000 to 2200 m a.s.l. It inhabits dry rocky and grassy limestone sites (Asenov, 1989). S. scardica is limited distributed in the country and has been included in the Red Book of Bulgaria (1984) as rare plant. The species is under governmental protection.

A chromosome number 2n=32 is reported, only the representatives of the species distributed the Olympus Mt. possess a chromosome number (32+O-2B) (Strid, 1965, Heywood, 1972, Contandriopoulos, 1978 etc.). Bulgarian authors confirm this chromosome number 2n=32 for the Bulgarian representatives too (Kozucharov & Kuzmanov, 1965; Markova & Goranova, 1994).

Bojchinov (1943), Ganchev & Asenov (1978) and Asenov & Ganchev (1986) investigate the anatomy and morphology of leaf, stem and bracts.

Biological activities

The pharmacological properties have not been well investigated. The herb and leave exudates of S. scardica have shown anti-inflammatory, anti-microbial, anti-bacterial and anti-rheumatic activities (Stojanov and Kitanov, 1960, Petkov, 1982, Abdel-Sattar et al., 1995). Due to the presence of microelements Fe, Se etc. in S. scardica, its extracts have been included in anti-anemia preparations (Đorđević et al., 1993).

In the Bulgarian folk medicine S. scardica is used as a loosening agent in bronchitis and bronchial asthma, against common cold and lung emphysema (Achtarov, 1939; Boijchinov, 1943; Asenov & Ganchev, 1978; Petkov, 1982; Ljubenov, 1984).

Chemical constituents

The earlier studies of Berger (1939) showed the presence of tannins. In S. scardica were found terpenoids, essential oils, phenols, flavonoids, iridoids, mucous substances, sugars (Bojchinov, 1943; Theodossian, 1962; etc.). The main part of the studies has been concentrated on terpenoids (Venturella et Bellino, 1979; Papanicolaou K., Kokkini S., 1984, Kokkalou, 1987, Menković et al., 1991, Komaitis et al. 1992, Baser et al. 1997, Todorova et al. in press). Mineral content - microelements (Fe, Cu, Zn, Co and Se) and macroelements (Ca, Mg, K and Na) has been reported. (Žarković et al., 1993).

The purpose of this investigation is to conserve this threatened plant by introduction, to improve some characteristics as biomass and content of biological active substances as well as the possibility to obtain a standardized drug.

In the Institute of Botany (Bulgarian Academy of Sciences, Sofia) since 1980 have been started studies on introduction of S. scardica. The seeds from fore Bulgarian populations in Middle and South Pirin, Slavjanka and Rhodopes mountains were germinated in a greenhouse and seedlings were placed in a experimental fields near Sofia. The blossoming stems (Sideritis scardicae herba) were harvested after first year of vegetation and dried. Dry material was measured as an indication of growth and development and content of biomass and biochemical substances (flavonoids and tannins).

The studies on cultivation of S. scardica following the next three stages:

I. Studies on ecological and biological peculiarities of different populations of country

The natural localities of S. scardica are concentrated in the mountain regions of the southern Bulgarian and are included in the Continental-Mediterranean climatic region. The plants survive low temperatures to -10°C under a comparatively regular and thick blanket of snow, which preserves them from frizzing. The plants are developed on a eutric cambisols. The species forms a well developed root system and 2-5 erect or procumbens stems with a length of 25-30 cm. Flowering begins at the end of June to the middle of July and lasts about 25 days. (Alikovski, 1989, Evstatieva et al., 1990, Yordanova, Apostolova, in press).

II. Studies on the factors determining the optimal growth of the plant.

The investigations show that seeds collected from the native populations have a physiological rest and show a low germination under laboratory and natural conditions (about 5%). Experiments have been carried out to increase the seed germination and seedling development by biological and chemical treatment. Best results are obtained during the cultivation, using stratification of seeds, treating with giberelin acid (1 and 1.5%) and CuSO₄ solutions (0.001%). These conditions increase the germination to 80%. The seedling development is characterized with a more intensive growth of the roots, stems and leaves (Evstatieva et al., 1990, Evstatieva & Popova, 1998).

III. Studies on the growth of the species under cultivation conditions.

Duplicate experiments to cultivate the species have been carried out during the period 1980-1990 in the Botanical garden (Institute of Botany, Sofia) and during 1991-2000 in the experimental field of the Institute near Sofia. A very good development of the species has been reached.

In the first year the culture forms only basalis leaves. In the second and third years a regular flowering and friuting is approached. The phases of growth and development of the cultures come on 1 month earlier in the region of Sofia.

The most intensive stem growth and formation of overground biomass is observed during the 3th and 4th year of vegetation when the number of flowering stems increases considerably, accompanied with an intensive branching (Table 1).

Branches of I and II-order, respectively with 1, 3 and 7 inflorescence of each flowering stem are formed. It must be noted that in the natural localities the stems are always not branched or seldom with branched of I-order. A period of stabilization occurs after the 5th-year of cultivation. During the 8th-year a gradual drop of the number of the flowering stems decrease is observed. During the 8- and 9-year parts of the plants begin to grow weak and even whole plants to vanish (4%). In Table 1 could be seen that during the 5-year the stems reach to medium 107.12 inflorescence of each plant. Single individuals possess to 130 inflorescence. The germination of cultivated seed is about 53%.

The content of biomass (Table 2) increase to the 5 year reach a weight of 242.29 g fresh and 93.19 g dry herb. The yield of 1 dka is about 1000 kg fresh and 380 kg dry herbs. In the next years the yield is small decrease.

The root system is very well developed comparing to the representatives of the natural populations. After the 4 year the roots reach a depth to 55 cm and spread in a diam. to 75 cm.

The content of flavonoids, iridoids and terpenoids is investigated from cultivated samples. Recently we isolated 4 flavonoids glycosides, 3 iridoids, diterpenoid siderol, ursolic and oleanolic acids ( Abdel Satar et al., 1993, 1995b, Taskova et al. 1997). After cultivation the amount of the active substances increased. A comparative assessment on the dynamics of accumulation of flavonoids and tannins in samples from natural populations and cultivars has been made (Table 3) (Evstatieva, in press ).

The amount of these compounds varied considerably due to season factors. The flavonoid content increased in the onset of vegetation and reached maximum values in the budding period. The lowest content is observed during full flowering and seed formation. Highest amounts of tannins were found at the beginning of the vegetation, and seed formation, and lowest - during the full flowering.

Different contents of flavonoids and tannins were observed in the different aerial parts. The highest content of flavonoids was found in the leaf mass, while the tannins prevailed in the stem parts. It was established that most suitable is to collect the cultivars in the end of May during the budding period up till the onset of flowering.

The antibacterial and antiviral activity in cultivated plants are confirmed (Abdel-Satar et al., 1995).

On the basis of these results we recommended the propagation to be predominantly by seeds, sowing in open air seeds-beds in seedling nursery in autumn or spring period in February-March. The seeds have slow germination and are needed stratification. The row distance is of 10 cm and 1-2 cm depth. The seed requirement is about 3 g/m². The seedling requirement of 1 dka can be grown on a 10 or 12 m² area and about 30 g stratification seeds. After sowing the seed-plots should be watering regularly.

More rarely the propagation is possible to be by seeds sowing directly in the field just prior to the winter into well-prepared soil, by using 250-400 g/dka.

The seedlings are placed in spring (May) or autumn (October) in production areas with the distance between rows is 50 or 60 cm and between plants in the row 50 or 40 cm. The plants should be irrigated and weeded out regularly by mechanized "inter-row" cultivation and hoeing the rows.

The shurbs can be harvested once in the second year of vegetation and generally twice in the following productive years. The plant should be harvested at the start of flowering in sunny weather. The cut plants are transported at once to dried. Drying is done in shady, airy places. Artificial dryers, which dry the plant at 40-50°C, results in better quality drug.

Expected yield in cultivated areas is about 150 kg/dka of dry herbs in the second year of cutting and 300 to 400 kg/dka in the next years. The drying ratio is 2.5:1

The obtained results give reason to recommend the breeding of the species in production areas. It is expected with this cultivation to produce about 150 kg/dka dry standardized drug during the 3th-year of vegetation and over 300 kg/dka between the 4- and 8-years.

The authors gratefully acknowledge the financial support for this study (Project B-907-99) provided by the National Research Foundation.

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