Chemical composition and antimicrobial activity of essential oils of Juniperus excelsa Bieb. (Cupressaceae) grown in R. Macedonia

Background

There are no information of the yield, chemical composition and antimicrobial activity of essential oils of berries (EOB) or leaves (EOL) of Juniperus excelsa Bieb. (Cupressaceae) growing wild in R. Macedonia.

Materials and Methods

Plant material was collected from two localities during two seasons. Essential oil composition was analyzed by gas chromatography/flame ionization detector/mass spectrometry (GC/FID/MS) and antimicrobial screening was made by disc diffusion and broth dilution method.

Results and Discussion

EOB yield ranged from 1.6-9.4 ml/kg and from 8.9-13.9 ml/kg for EOL. Two chemotypes of essential oil were differentiated, a-pinene-type (with 70.81% a-pinene in EOB and 33.83% in EOL), also containing limonene, b-pinene and b-myrcene while the sabinene-type (with 58.85-62.58% sabinene in EOB and 28.52-29.49% in EOL), was rich in a-pinene, b-myrcene, limonene, cis-thujone, terpinolene and a-thujene. The most sensitive bacteria to the antimicrobial activity of EOB was Haemophilus influenzae (MIC = 31 ml/ml). EOL have showed high activity towards: Staphylococcus aureus, Streptococcus pyogenes and Haemophilus influenzae (MIC = 125 ml/ml). The pinene-type of essential oil showed moderate activity against Streptococcus pneumoniae, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pyogenes, Corynebacterium spp. and Campylobacter jejuni (MIC >50%). The sabinene-type of the oil showed moderate activity to Streptococcus pyogenes, Haemopilus influenzae, Campylobacter jejuni and Escherichia coli (MIC >50%). No activity was observed toward Candida albicans.

Conclusion

The analysis of EOB and EOL revealed two chemotypes (a-pinene and sabinene type) clearly depended on the geographical origin of the Macedonian Juniperus excelsa which also affected the antimicrobial activity of these oils.