Profile of phenolic compounds and carotenoids of Arrabidaea chica leaves and the in vitro singlet oxygen quenching capacity of their hydrophilic extract.

Arrabidaea chica (Brazilian name = pariri) is a plant species that belongs to the Bignoniaceae family, occurring in tropical America and widespread in the Amazonian region of Brazil. In this study, the phenolic compound and carotenoid profiles of A. chica leaves were determined by HPLC-DAD-MS. Scutellarin was identified as the main phenolic compound (15,147.22 µg/g, dry basis, d.b.) and lutein (204.28 µg/g, d.b.), ß-carotene (129.5 µg/g, d.b.) and α-carotene (79.86 µg/g, d.b.) as the major carotenoids. Moreover, A. chica leaves presented 152.7 µg/g of ascorbic acid (fresh weight). For the first time, the carotenoid profile and ascorbic acid contents were reported for A. chica leaves. Regarding the antioxidant capacity, A. chica extract was able to scavenge ABTS radical (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)), and for the first time, the protective effect against singlet oxygen (1O2) was reported. The A. chica extract was efficient as ABTS radical scavenger (86.81 µM Trolox/g of fresh leaves) and inhibited the degradation of tryptophan by 1O2 in a concentration-dependent manner with an IC50 at 177 µg/mL. Thus, A. chica leaves can be exploited as a promising source of bioactive compounds that may be useful to human health or food systems against oxidative damage.