Variability of Phenolic Compounds and Biological Activities among Wormwood Extracts Originated from Different Bioclimatic Zones

Aim: Wormwood is an aromatic spice widely used as flavor, antioxidant and antimicrobial agents. In this study the variability of total phenolics, total flavonoids, antioxidant, antibacterial and antifungal activities among leaves extracts originated from four Tunisian regions were assessed.

Study Design: All the analyses were achieved in triplicate.

Methodology: Fresh leaves of Artemisia absinthium L. were harvested from four regions of Tunisia representing four different bioclimatic areas ranging from humid to arid zone. Phenolic and flavonoid contents were assessed based on colorimetric methods. The antioxidant activities of the studied extracts were tested based on DPPH and ABTS methods. The antibacterial and antifungal activities of Artemisia absinthium phenolic extracts were determined against ten indicators microorganisms by measuring the diameter of the growth-inhibition zone in millimeters, the minimum inhibitory concentration and the minimum bactericidal concentration.

Results: Considerable levels of bioactive phenolic compounds were revealed for the studied extracts. The highest levels of phenolic compounds were recorded for Gafsa site (Total Phenolic Content=127.5±5.22 mg GAE/g DW, Total Flavonoid Content=34.26±2.48 mg RE/g DW) while the lowest contents were observed for Ghar Dimaou locality (Total Phenolic Content =94.23±4.81 mg GAE/g DW, Total Flavonoid Content=26.95±1.98 mg RE/g DW). Similarly, considerable levels of antioxidant capacities were revealed based on both DPPH and ABTS tests with a significant variation according to the studied site. All the investigated extracts presented antimicrobial capacities against the ten tested strains with a variation according both to the extract origin and to the tested microbial strain. Especially, the highest toxicity was recorded against the species Aspergillus niger (MIC: 3.12 µg/ml, MBC: 6.25 µg/ml) and Candida albicans (MIC: 6.25 µg/ml, MBC: 12.5 µg/ml). Comparable levels were observed for bacterial strains with slight more effectiveness against Gram positive strains.