The antimicrobial activity of petrol-ether extracts of herbal species of the genus Hypericum L. (H. maculatum Cranc., H. rumelicum Boiss., H. perforatum L. and H. olympicum L.) was compared. All the investigated extracts have shown good antimicrobial activity. H. olympicum L. extract has exerted the strongest action. The investigated extracts can be used for making the antimicrobial parapharmaceutical preparations.

Genus Hypericum L. is very widely spread in Europe, North Asia, North Africa, Australia, New Zealand and America (1-4). Especially rich findings are in Germany, Ukraine, Italy and on the Balkan (5). The investigations of the genus Hypericum L. have shown that in Serbia there are 19 identified species, with several lower taxonomic categories. Hypericum perforatum L. is the most represented species of the mentioned genus (6).

Intensive systematic investigations of herbal species of the genus Hypericum L. are being carried out in the Pharmaceutical and Chemical Industry AD "Zdravlje"- Leskovac. Two pharmaceutical (Biosenzal and Sedival) and one cosmetic (hair shampoo) preparation have been registered on the basis of these investigations.

The antimicrobial properties of the petrol-ether extracts of H. maculatum Cranc., H. rumelicum Boiss., H. perforatum L. and H. olympicum L. were compared within the described investigations of antimicrobial properties of the essential oils from the herbal species of the genus Hypericum L., which are being carried out in co-operation with the Faculty of Technology in Leskovac.

In the previous study (7), where the antimicrobial activities of the extracts of St. John's wort obtained with solvents of different polarity were compared, we came to the conclusion that petrol-ether extracts exert the strongest antimicrobial action. That is why the petrol-ether extracts were used in this investigation.

The herbal material (H. maculatum Cranc., H. rumelicum Boiss., H. perforatum L. and H. olympicum L.), originating from Southeast Serbia, was used in this investigation. The herbal material was dried in thin layer at room temperature and then ground on the electric mill and sieved through the 1 mm sieve.

The ratio of herbal drug to solvent of 1:10 was used for extract preparation. The extraction was performed with petrol-ether by maceration procedure during 24 h.

The antimicrobial activity of the extracts was investigated by diffusion method on the cellulose disc, by application of the following test microorganisms: Bacillus subtilis S, Escherichia coli 95, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus ATCC 6538, Sarcina lutea ATCC 9341, Salmonella enteritidis, Aspergillus niger, Candida albicans ATCC 24493 and Saccharomyces cerevisiae ATCC 9763.

Fisher Lilli apparatus for measuring the inhibition zones in antibiotics reads out the inhibition zones.

Table 1 shows the results of the investigation of antimicrobial activities of petrol-ether extracts of the herbal species of the genus Hypericum L. (H. maculatum Cranc., H. rumelicum Boiss., H.perforatum L. and H. olympicum L.).

All the investigated extracts have exerted good antimicrobial activity. Petrol-ether extract of H. olympicum L. has exerted the strongest activity. It is significant that the petrol-ether extract of H. olympicum L., has exerted the best effect on the test fungus Candida albicans which is known by its resistance.

The investigated extracts may be used for making antimicrobial parapharmaceutical preparations.

1. The investigations of antimicrobial activity of petrol-ether extracts of the herbal species of the genus Hypericum L. (H. maculatum Cranc., H. rumelicum Boiss., H. perforatum L. and H. olympicum L.) have shown that all the investigated extracts exert good antimicrobial activity.

2. H. olympicum L. extract has exerted the strongest antimicrobial activity.

3. It is significant that petrol-ether extract of H. olympicum L. exerts the strongest antimicrobial activity on the fungus Candida albicans, known by its resistance.

1. Hegi G. (1975): Illustrierte Flora von Mittelleuropa V, Hansen Verlag, Mü nchen.

2. List P.H., Horhammer L. (1976): Hagers Hanbuch der pharmazeutischen Praxis, Bd. V, Springen-Verlag, Berlin.

3. Hickey M., King C. (1981): 100 Families of Flowering Plants, Cambridge University Press, Cambridge.

4. Wichtl M. (1986): Hypericum perforatum L. - Das Johanniskarut. Zeitschrift fü r Phytotherapie 3, 87-90.

5. Hoppe H.A. (1987): Drogen Kunde I. Walter de Gruyter, Berlin-New York.

6. Ranđelović N. (1987): Fitocenološko-ekonomske karakteristike brdskih travnjaka jugo-istočne Srbije, Doktorska disertacija, PMF, Zagreb.

7. Šmelcerović A., et al. (1998): Mikrobiološka i hemijska ispitivanja biljne vrste Hypericum perforatum L. (kantarion) sa lokaliteta Sobina (okolina Vranja), III Simpozium "Savremene tehnologije i privredni razvoj", Zbornik radova, Leskovac, 27.