Barks Essential Oil, Secondary Metabolites and Biological Activities of Four Organs of Tunisian Calligonum azel Maire

This study is the first to investigate the chemical composition of barks essential oil (EO), secondary metabolites and biological activities of the MeOH and infusions extracts of seeds, leaves, barks and roots of Calligonum azel Maire (Polygonaceae) harvested from Tunisian desert. The gas chromatography/mass spectrometry (GC/MS) results showed the presence of fifty‐four compounds in barks EO. The major components were: viridiflorol (14.6%), α‐eudesmol (8.65%), trans‐caryophyllene (6.72%), elemol (6.63%), β‐eudesmol (6.21%). The obtained results showed that C. azel is a very rich plant in secondary metabolites. High contents in polyphenols, flavonoids and tannins were observed in both extracts of all studied organs. Significant differences were found between both extracts of the four organs. Thus, polyphenols and tannins were more abundant in leaves infusion extract, while, flavonoids showed a high level in barks extract. The antioxidant activity data demonstrated that all extracts showed strong antioxidant and radical scavenging activities. The MeOH extracts presented potential for antibacterial and antifungal activities against all tested microorganisms. The inhibition zones diameters and minimal inhibitrice concentration values were in the range of 9 – 15 mm and 2.5 – 20 μg/ml, respectively. This study demonstrated that C. azel can be regarded as an excellent plant source for natural antimicrobial agents.