Effect of Latitude and Altitude on the Terpenoid and Soluble Phenolic Composition of Juniper (Juniperus communis) Needles and Evaluation of Their Antibacterial Activity in the Boreal Zone

The demand for dry juniper (Juniperus communis) needles as a raw material for the food, pharmaceutical, and cosmetic industries has increased rapidly in recent years. Juniper needles are known to be rich in terpenoids and phenolics, but their chemical composition and antibacterial properties have not been well-characterized. In this study, we describe the soluble phenolic and terpenoid composition of juniper needles collected in Finland (n = 125) and demonstrate that the concentration of these compounds clearly increased with latitude and altitude with, however, a stronger latitudinal effect (a higher content of monoterpenoids, proanthocyanidins, and flavonols in northern latitudes). Analysis of methanolic extracts showed quite good activity against both antibiotic-sensitive and -resistant Staphylococcus aureus strains and suggested an important role of the soluble phenolic fraction. Finally, we demonstrate the relative lack of toxicity of juniper extracts on keratinocytes and fibroblastic cells, raising the possibility of their use in preventing bacterial skin infection.