title: Effect of drought on safflower natural dyes and their biological activities.
abstract: Drought is the main abiotic constraint that affects crop species behaviour regarding bio-chemical responses. The current study was conducted to examine the effect of water deficit on growth, phenolic and carotenoid contents as well as the antioxidant and antimicrobial activities of two Carthamus tinctorius varieties (Jawhara and 104) flowers. Hence, plants were treated with different levels of water deficit: control (100 %), moderate water deficit (50 %) and severe water deficit (25 %). Obtained results showed that plant growth was significantly (p < 0.05) reduced under 50 %. Drought increased flower phenolic acids contents especially gallic acid where they increased significantly (p < 0.05) by 2.73 fold (104) and by 2.87 fold (Jawhara) with respect to controls under 50 %. However, the amounts of this major compound were reduced at 25 % by 9.66 % (104) and 3.83 % (Jawhara). Similar to phenolic compounds, total carotenoid content was at its highest level especially for Jawhara with an increase by 35.19 % at 50 %. On the other hands, C. tinctorius flowers extracts exhibited high antiradical activity as compared to BHT. A gradual increase by 35.29 % (Jawhara) and 33.33 % (104) especially under 25 % was observed. Moreover, under 50 %, the antimicrobial activity increased significantly (p < 0.05) by 30 % and 10.05 % against Aspergillus carbonarus and Pseudomonas aerogenosa, respectively. Taken together, our findings suggest that C. tinctorius could be a raw material for production of natural dyes under moderate salinity conditions.
authors.affiliation: Laboratory of Bioactive Substances, Biotechnology Center in Borj-Cedria Technopol, Tunisia.
authors.forename: Nidhal
authors.initials: N
authors.lastname: Salem
authors.affiliation: Laboratory of Bioactive Substances, Biotechnology Center in Borj-Cedria Technopol, Tunisia.
authors.forename: Kamel
authors.initials: K
authors.lastname: Msaada
authors.affiliation: UR Ecophysiologie Environnementale et Procédés Agroalimentaires, BiotechPole de Sidi Thabet Université de La Manouba, Tunisia.
authors.forename: Wissal
authors.initials: W
authors.lastname: Dhifi
authors.affiliation: Laboratory of Bioactive Substances, Biotechnology Center in Borj-Cedria Technopol, Tunisia.
authors.forename: Jezia
authors.initials: J
authors.lastname: Sriti
authors.affiliation: Laboratory of Bioactive Substances, Biotechnology Center in Borj-Cedria Technopol, Tunisia.
authors.forename: Houda
authors.initials: H
authors.lastname: Mejri
authors.affiliation: Laboratory of Bioactive Substances, Biotechnology Center in Borj-Cedria Technopol, Tunisia.
authors.forename: Ferid
authors.initials: F
authors.lastname: Limam
authors.affiliation: Laboratory of Bioactive Substances, Biotechnology Center in Borj-Cedria Technopol, Tunisia.
authors.forename: Brahim
authors.initials: B
authors.lastname: Marzouk
keywords: Carthamus tinctorius flower; antimicrobial activity; antioxidant activity; carotenoids; drought; phenolic composition