The hydrodistilled essential oils of the aerial parts of S. ringens collected in June 1997 (sample A), and June 1999 (sample B), were analyzed by GC and GC-MS. Seventy-five constituents representing 99.82% and 99.86% of the total oil were identified. The most abundant constituents of the S. ringens oils were 1,8-cineole (50.74-46.42%), a-pinene (10.64-12.85%), bornyl acetate (6.54-4.53) and b-pinene (4.34-5.64%). The biological activity of the essential oil (Sample B 1998) was evaluated in vitro against six Gram (±) bacteria and three pathogenic fungi.

In our continuing research on the essential oils of Greek plants, we have investigated the essential oil of Salvia ringens Sibth. & Sm. (sectio Salvia) and its biological activity. Salviaringens is a perennial plant growing wild in the Mediterranean area, on dry rocky places, particularly in open Pinus nigra woodland generally between 500 and 1600 m, occasionally up to 2000 m or down to sea level (1). To our knowledge the oil of Salvia ringens has not been studied previously.

Growing wild plants of S. ringens were collected during the flowering stage in June, 1997 (sample A) and June, 1998 (sample B) on mountain of Parnes at an altitude of 400 m. Air-dried leaves were subjected to hydrodistillation for 3 hours, using a modified Clevenger-type apparatus. The oils were dried over anhydrous sodium sulfate and were submitted to GC and GC/MS analyses. The GC conditions used were: DB-5 (30 m0.32 mm) fused silica column; carrier gas He (2 ml min^-1); on column injector 200°C; FID 250°C; column temp. 60°C for 5 min and then was heated to 280°C with a 3°C/min rate on a Varian 3300 Gas Chromatograph. Mass spectra were obtained from a Hewlett Packard 5973-6890 GC-MS system operating on EI mode at 70 eV (split ratio 1/10), equipped with a DB-5 fused silica column (30 m0.25 mm; film thickness 0.25 mm). The thermal program was the same with that used for the GC analysis. The identification of the chemical constituents was based on comparisons of their relative retention times and mass spectra with those obtained from authentic samples and/or the NIST/NBS and Wiley libraries of mass spectra.

The antibacterial and antifungal activity of the essential oil (Sample B) against Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (ATCC 12228), Escherichia coli (ATCC 25922), Enterobacter cloacae (ATCC 13047), Klebsiella pneumoniae (ATCC 13883), Pseudomonas aeruginosa (ATCC 227853) Candida albicans, Candida vaginalis and Torulopsis glabrata were determined, using the dilution technique (2). The minimum inhibitory concentration (MIC) was measured for the oil, a-pinene and 1,8-cineole (Table 2). Standard anitibiotics (netilmicin and amoxicillin with clavulanic acid) were used in order to control the sensitivity of the test organisms.

The oils obtained from the growing wild S. ringens were yellowish and possessed a strong odor. The volatile components identified by GC and combined GC/MS are listed in Table 1 in elution order from the HP 5MS column. Seventy-five compounds representing the 99.82% and 99.86% of the oils were identified. There were obvious qualitative similarities between the two oils, although the percentage of each individual component differed. The monoterpene alcohols (64.94% and 57.03% of sample A and B, respectively) and monoterpene hydrocarbons (25.06% and 27.57%) formed the two main fractions of the oils. The sesquiterpene fraction of sample B (15.27%) was richer than that of sample A (9.82%). Sample B was characterized by a higher content of monoterpene hydrocarbons with the exception of p-cymene. The major constituents of both examined oils were 1,8-cineole (50.74, 46.42%), a-pinene (10.64, 12.85%), bornyl acetate (6.54, 4.53) and b-pinene (4.34, 5.64%).

In the antimicrobial screening, the oil appeared to be inactive against the two Gram (+) bacteria (S. aureus and S. epidermidis), while it showed a very strong activity against the tested Gram (-) bacteria (MICs 2.75-3.75 mg/ml) and a significant one against the three tested fungi (MICs 0.50-0.75 mg/ml). In the screening standards of pure monoterpenoids a-pinene and 1,8-cineole were tested on the same cultures under identical conditions to compare their activity with that of the investigated oil. The results suggest that the activity of the oil could be attributed, to a considerable degree, to the existence of 1,8-cineole.

1. Hedge I.C.(1976): Salvia L., In: Tutin T.G., Heywood V.H., Burgers N.A., Moore D.M. Valentine S.M., Webb D.A. (Eds.), Flora Europaea, Cambridge University Press, Cambridge, Vol. 3, 145.

2. Roussis V., Tsoukatou M., Chinou I.B., Ortiz A.(1998): Composition and Antibacterial Activity of the Essential oils of Helichrysum rupestre and H. ambiguum Growing in the Balearic Islands, Planta Medica, 64, 675-6.

3. Van den Dool H., Kratz P.D.(1963): A Generalization of the Retention Index System Including Linear Temperature Programmed Gas-Liquid Partition Chromatography, J.Chromatogr. 11, 463-71.