Biological activity, and volatile and phenolic compounds from five Lamiaceae species

Lamiaceae, a family of flowering plants, have been historically used as culinary herbs, shrubs and medicinal plants. With this study, the volatile organic compounds (VOCs) of the five species of the Lamiaceae family (Thymus cilicicus, Clinopodium nepeta L., Nepeta italica L., Thymbra spicata L. and Ziziphora clinopodioides) that grow in Turkey were identified by the SPME/GC-FID/MS method. The five species were screened in order to reveal their antibacterial and antioxidant activities. Phenolic compound analyses of five species were performed by using RP-HPLC with diode array detection. Among the total number of 73 compounds that were identified, alpha-pinene (2.2%-13.8%), beta-pinene (0.3%-25.9%), p-cymene (0.7%-17.9%), gamma-terpinene (0.4%-22.0%), carvacrol (0.1%-40.2%), sabinene (1.2%-34.2%), terpinen-4-ol (0.2%-27.5%), (E)-beta-caryophyllene (0.1%-13.8%) and (E)-beta-farnesene (0.4%-19.7%) were found to be the most plentiful ones. The minimal inhibitory concentration (MIC) values of the methanol extracts of the five species of the Lamiaceae family were investigated, and the results were in the range of 23-959 mu g/mL; the most pronounced antibacterial activities were determined to be against Mycobacterium smegmatis (23-291 mu g/mL). All of the methanol extracts possessed effective antioxidant capacity (IC50: 1.82-28.18 mu mol/L Trolox/g sample) as estimated from the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assays. Additionally, the effect of phenolics, especially benzoic acid (86.27, 27.85, -, 13.11, 9.59 mg/g extract, respectively), on the biological properties of the methanol extracts of the five species of the Lamiaceae family, was investigated.

Automated summary

This study identified the volatile organic compounds of five species of Lamiaceae plants in Turkey and screened them for antibacterial and antioxidant activities, while also analyzing their phenolic compounds. The results showed significant antibacterial and antioxidant properties in these plants.