The aim of this study was to reveal the phytochemical constituents, antioxidant and antimicrobial activity of Ajuga orientalis. According to the antimicrobial results, the methanol extract of A. orientalis showed a MIC value of 312.5 µg/mL against the tested pathogenic bacterial strains. Anticandidal activity of extract was found as 156.3 µg/mL both against Candida albicans and C. parapsilosis strains. Whereas the extract was more effective against C. tropicalis with the MIC value of 78.1 µg/mL. The in vitro DPPH radical scavenging activity of the extract was determined as IC50=0.4 ± 0.02 mg/mL whereas the standard BHT IC50 was 0.01 ± 0.00 mg/mL. Trolox Equivalent Antioxidant Capacity (TEAC) of extract was determined 1.3 mM TEAC, while BHT, 1.9 mM TEAC.

Objectives: In this study, it was aimed to characterize the phenolic contents of Ajuga reptans L., Ajuga salicifolia (L.) Schreber and Ajuga genevensis L. and to investigate their in vitro antioxidant and antimicrobial activities. Materials and Methods: Air dried aerial parts of A. reptans L., A. salicifolia (L.) Schreber, and A. genevensis L. collected from Turkey were extracted with methanol (70%), and the phenolic composition of the crude extracts was analyzed by liquid chromatography with tandem mass spectrometry (LC-MS/MS) method. To determine the total phenolic content the Folin-Ciocalteu method was used. The radical scavenging activities of the extracts were evaluated by the photometric 1,1-diphenyl-2-picrylhydrazyl radical, and trolox equivalent antioxidant capacity assays (TEAC). Furthermore, Ajuga sp. extracts were tested against Escherichia coli NRRL B3008, Staphylococcus areus ATCC 6538, Salmonella thyphimurium ATCC 13311, Bacillus cereus NRRL B-3711, Candida albicans ATCC 90028, Candida tropicalis ATCC 1369, and Candida parapsilosis ATCC 22019 using the in vitro broth dilution assay. Results: The LC-MS/MS analyses identified 19 compounds. The amount of total phenolics ranged from 30.0 to 42.2 mg gallic acid equivalent/g in all extracts. According to the results of TEAC assay, the tested extracts were found to have relatively high activity at 1.2-1.5 mM concentrations. Ajuga sp. extracts inhibited all tested microorganisms; however, C. albicans, C. tropicalis, and C. parapsilosis exhibited relatively more susceptibility (minimum inhibitory concentration: 156.25 mu g/mL) compared to the bacteria tested. Conclusion: The antioxidant activities of all extracts were determined for the first time by the TEAK method, and the in vitro antimicrobial activity of A. salicifolia was investigated for the first time against selected strains.

The genus Centaurea L. (Asteraceae) is widely distributed in Turkey and used as folk remedies for their several biological effects. In the present study hydrodistilled essential oils of Centaurea lycopifolia and Centaurea cheirolopha were analysed by gas chromatography and gas chromatography-mass spectrometry (GC-MS) techniques, simultaneously. Caryophyllene oxide (13.4 %), spathulenol (12.1 %), phytol (6.3 %), hexadecanoic acid (6.1 %) and nonacosane (6.1 %) as the main constituents of C. lycopifolia oil, while hexadecanoic acid (25.8 %), heptacosane (10.8 %), tetradecanoic acid (8.1 %), nonacosane (7.7 %) and phytol (7.4 %) were the main constituents of C. cheirolopha essential oil. The oils of C. lycopifolia and C. cheirolopha were subjected to a screening for their antibacterial activities by using broth microdilution technique. The oils demonstrated weak to moderate antibacterial effects against the tested pathogenic bacteria strains with the MIC values between 4000 to 125 μg/mL.