Bulgaria is relatively small in size (111.000 km²) but it is rich in biological diversity - 7835 plant species: Algae - 3000, Lichenes - 710, Bryophyta - 660, Lycopodiophyta - 7, Equisetophyta - 12, Polypodiophyta - 30, Pinophyta - 16, Magnoliophyta - 3400 (55). In the practice of the folk medicine about 750 species, mainly vascular plants, are used. However, for the needs of pharmaceutical industry, phytoterapy and for export 200 species are applied more frequently. In the recent years the attention of the Bulgarian scientists is directed to four main issues:

1. Study and protection of the genefund of medicinal and aromatic plants;

2. Quantitative and qualitative analyses of the active substances in some rare and valuable species;

3. Introduction and cultivation of the economically valuable plants;

4. Standardisation and control of herbal drug raw material.

In 1995 "Chorological atlas of the medicinal plants in Bulgaria" was published, containing data about the chorology, ecological and biological characteristics, reproductive capacity, resources and measures for protection of 196 wild growing species. The biodiversity of the rare medicinal and aromatic plants and species with restricted regime of use was studied in the mountains of Znepole floral region (12), Rila National Park (76), and Central Balkan National Park (10). On the other hand, extensive biological and ecological investigations were carried out with some protected by law and rare species, such as Arctostaphylos uva-ursi (L.) Spreng. (58), Ruta graveolens L. (59) Sideritis syriaca L. (9), Alkanna tinctoria (L.) Tausch (15) etc. The problem of the studying and protection of some medicinal plants in the forest lands was also discussed (66). The biotechnological methods were applied for the reproduction of Leucojum aestivum L. (64,63), Atropa belladonna L. (5), Glycyrrhiza glabra L., Origanum heracleoticum etc. (72) in order their genefund to be protected. The genetic material from the protected and rare species is conserved in two ex situ collections: the Experimental Field of the Institute of Botany, BAS with 120 species (6), the Experimental Field of the Institute of Plant Genetic Resources, Sadovo with 38 species (72). Some of those investigations were financed by the National Research Foundation (NRF), Bulgarian Ministry of Environment and Waters (MEW), Global Environmental Fund (GEF) etc.

A study of the content and dynamics of accumulation of some active compounds in medicinal plants has been carried out in the period of 1990-2000:

• flavonoids, tannins and hypericin in the herbs of Hypericum perforatum L. and H. maculatum Grantz. (Guttiferae) (26,29);

• flavonoids, phenolic and triterpenic acids in Mentha spicata group (Lamiaceae) (65);

• flavonoids and tannins in Alchemilla species (Rosaceae) (74);

• flavonoids in Achillea species (Asteraceae) (38);

• plumbagin in the roots and herb of Plumbago europaea L. (Plumbaginaceae) (34);

• alkannin in the roots of Alkanna tinctoria (L.) Taush. (Boraginaceae) (14);

• antraquinones in Rumex alpinus L. (Polygonaceae) (7);

• tannins in rhizomes and herb of Geranium macrorrhizum L. (Geraniaceae) (11);

• polyphenols in Geranium sanguineum L. (Geraniaceae) (19);

• polyphenols in Vaccinium species (Ericaceae) (23);

• ruscogenin in the roots and the rhizomes of Ruscus aculeatus L. (Liliaceae) (46) and

• some active compounds in Glycyrrhiza glabra L. (Fabaceae) (13).

Some methods for quantitative determination and separation of the active compounds have been applied:

a titrimetric method for total alkaloid determination in overground parts of Tribulus terrestris L. (Fabaceae) (50);

a densitometric method for quantitative determination of the xanthone isomers in Cratoxylum pruniflorum Kurz. and Hypericum aucheri Jaub. et Spach. (Guttiferae) (39) and

a method for separation of flavonoid and xanthone aglycones (28).

By using modern technics as HPLC, GC/MS, IR, UV, EI, ¹H, ¹³C NMR etc., the qualitative analyses have been worked out for the following species.

Essential oil in some aromatic plants:

• Hyssopus officinalis taxa (Lamiaceae) (70);

• Salvia species (Lamiaceae) (71);

• Thymus species (Lamiaceae) (36);

• Acorus calamus L. (Araceae) (8) and

• Nepeta species (Lamiaceae) (18).

Phenolic acids, xanthones, catechins, flavonoids and related phenolic components:

• Hypericum maculatum Grantz. (Guttiferae) (33);

• Gentiana asclepiadeae L. (Gentianaceae), where one of the isolated components (naphtodipyranodion) is a new natural product (30,35);

• Melaleuca leucadendron L. (Myrtaceae) (31);

• Stellaria media (L.) Vill. (Caryophyllaceae) (25);

• Potentilla reptans L. (Rosaceae) (27);

• Platycodon grandiflorus (Jacq) A. CD (Campanulaceae) (16);

• Astragalus onobrychis L. (Fabaceae) (2);

• Astragalus vesicarius L. (Fabaceae) (42);

• Achyranthes bidentata Bl. (Amaranthaceae) (48);

• Pulsatilla slaviankae (Zimm) D. Jord. et Koz. (Ranunculaceae) (49) and

• Solidago virgaurea L. (Asteraceae) (24).

• Astragalus onobrychis L. (Fabaceae) (41).

• Berberis vulgaris L. (Berberidaceae) (56) and

• Ruta graveolens L. (Rutaceae) (75).

Some of the active compounds were successfully used as chemotaxonomic markers for the clarification of the taxonomy of some critical groups or families:

• xanthone C-glucosides mangiferin and isomangiferin - Hypericum species (Guttiferae) (32);

• flavonoids - Geranium species (Geraniaceae) (22);

• exudate flavonoid aglycones - Achillea species (Asteraceae) (21);

• steroidal sapogenins - a chemotaxonomic comparison of the genera Asparagus and Ruscus (Liliaceae) (46);

• triterpenoid sapogenins (soyasapogenol B) - Astragalus species (Fabaceae) (43);

• iridoids - Genera Veronica (Scrophulariaceae) and Plantago (Plantaginaceae) (67);

• iridoids, flavonoids, terpenoids - Lamiaceae, Scrophulariaceae, Rubiaceae (68) and

• terpenoids - Artemisia species (Asteraceae) (69).

The application of flavonoids, isoenzymes and pigments as markers in the phytomonitoring investigations has been also discussed (51,52,53,57). There are some data about the biological activity of some active compounds as the following:

• antiviral, antiherpes, antiradiation effect of the Geranium sanguineum polyphenol extracts (60,61,62,73);

• stronger immunostimulant effect of the triterpene saponins with sapogenin soyasapogenol B (37) and

• insecticidal properties of the pyrrolizidine alkaloids from the Senecio sp. (4).

According to the recommendations of the Ministry of Environment and Waters (Regulation #973/1991) successful experiments with introduction and cultivation of some wild growing plants as Alchemilla species, Carlina acanthifolia All., Hippophae rhamnoides L., Sideritis scardica L. were carried out in this period.

On the basis of the genetic material from wild growing and introduced species from abroad plant varieties were selected. The List of Varieties and Hybrids Permitted for Distribution in the Republic of Bulgaria (1995) includes 66 medicinal and aromatic plant varieties, achieved mainly of the Institute for Roses, Essential Oil and Medicinal Plants, Kazanluk; the Institute of Botany - BAS, Sofia; the High Institute of Agriculture, Plovdiv; the Institute of Plant Genetic Resources, Sadovo and the Institute of Plant Genetics - BAS, Sofia.

Efforts of the Bulgarian scientists working in the field of a complex analysis of the standardization documents, which determine the quality of the herbal drugs in Bulgaria, have been made. Results and recommendations for development of an effective system for standardization and control of the herbal drug raw material, according to the recent scientific requirements are presented (47). By the pharmacognostical study of rhizoma cum radicibus and folium Urticae contemporary indexes for a new standard has been developed which should provide higher requirements for that herb as treating means and its realization on the international market (44,17).

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