RESUMO
In the current study, antioxidant, antibacterial activities, and the phenolic compositions of extracts from Helianthemum canum L. Baumg. (Apiaceae) aerial parts were investigated for the first time. The H. canum was extracted with 70% methanol (HCMeOH) and water (HCW). Both extracts were determined by total phenolic contents (3 mg/ml), flavonoids (1.5 mg/ml), flavonols (1.5 mg/ml), qualitative-quantitative compositions, iron (II) chelation activities (0.1 - 5 mg/ml), free radical scavenging activities (DPPH⢠: 0.01 - 0.6 mg/ml and ABTS+⢠: 0.125 - 0.5 mg/ml) and the effect upon inhibition of ß-carotene/linoleic acid co-oxidation (1 mg/ml). The peroxidation level was also determined using the thiobarbituric acid method (0.01 - 1.5 mg/ml). The results of the activity tests given as IC50 values were estimated from non-linear algorithm and compared with standards. Antibacterial activities of extracts and standards were evaluated against Gram-negative and -positive ten standard strains using disc diffusion and broth microdilution methods. The MIC results (312.5 - 2500 µg/ml) against tested microorganisms varied from 625 to 2500 µg/ml. In HPLC analysis, 3,5-dihydroxybenzoic acid was found as the main substance in both extracts. These results showed that HCMeOH was richer in phenolic compounds (284.13 ± 0.30 mg GAE/g extract) from HCW (244.55 ± 0.35 mg GAE/g extract). In conclusion, H. canum extracts showed in vitro antibacterial and antioxidant activities.