A.M. Oueslati 1,2*
G. Rigane 3,4
H. Ghazghazi 5
R. Ben Salem 3
S. Hamdi 6
M. Hannachi 6
H. Jouili 2
Y. L’ammari 2
1 Laboratory of lipids Biochemistry, Faculty of Sciences of Tunis, El Manar 2090,Tunis- -Tunisia.
2 Laboratory of forest Ecology , National institute of research in Rural engineering, water and forests (INRGREF) of Tunis. Tunisia
3Laboratory of organic chemistry and physics ,UR11ES74, Faculty of Sciences of Sfax, University of Sfax, B.P 1171, 3038 Sfax, Tunisia.
4 Department of Physics & Chemistry, Faculty of Sciences and Technology of Sidi Bouzid , B. P 380, 9100, Sidi Bouzid, University of Kairouan, Tunisia.
5 Laboratory of management and valorization of Forest Resources National institute of research in Rural engeneering, water and forests (INRGREF) of Tunis. Tunisia
6 High institute of Biotechnology of Béja , Avenue Habib Bourguiba Béja 9000, BP: 382, Béja-Tunisia
Abstract - Phenolic compounds make up one of the major families of secondary metabolites widely distributed in the plant kingdom, and they are found in foods of vegetable origin, constituting an integral part of our daily diet and in wild species as the major bioactive components that has shown to exhibit anti-carcinogenic, anti-microbial, antioxidant and anti-viral activities. The present work is devoted to the study of antiradical and antimicrobial activities of aqueous and organic extracts (Ethanol 70%) of Trachyspermum ammi (T.ammi) aerial parts. In order to compare its antioxidant activities, samples were extracted with 100% water or 70% ethanol. Their total phenolic content (TPC), flavonoid (TFC) and condensed tannin (CT) contents as well as DPPH and ABTS assays were measured. In addition, the antibacterial and antifungal activities of all extracts were also investigated against six human pathogenic bacteria and one fungal strain (Candida albicans). Our result has shown that, aqueous extract has demonstrated the best concentration in TPC (162.17 mg GAE.g-1 dw) and TFC (91.22 mg RE.g-1 dw) as compared to the ethanolic fraction. However, no significant difference (p>0.05) was observed in term of condensed tannin content (14.85 vs 14.23 mg CE.g-1 dw). Furthermore, the aqueous extract has shown the best antioxidant activity with IC50 values of 4.26 and 4.89 µg.ml-1 for ABTS and DPPH assays, respectively. The assessment of antimicrobial activity has shown that the remarkable inhibition of the bacterial and fungi growth was observed almost against all strains notably for the ethanolic extract for which all tested microbial strains was highly sensitive with an inhibition zone that significantly exceed that of the antibiotic tested under the same conditions. The results of our current study has demonstrated that extracts from T.ammi aerial parts can be used as a practical food additive or preservative in various food products and as a potential source of antimicrobial components.
Keywords: Antimicrobial activity, Flavonoids, Free radicals, Organic extract, polyphenols, Trachyspermum ammi aerial parts, Condensed tannin.