The influence of collection zone on glucosinolates, polyphenols and flavonoids contents and biological profiles of Capparis sicula ssp. sicula.

This study aimed to evaluate the influence of collection zone on total phenol, flavonoid and glucosinolate contents and antioxidant and anti-inflammatory activities of caper (Capparis sicula ssp. sicula). This species has been characterized through the detection, isolation and quantitative evaluation of chemical markers (polyphenols, flavonoids and glucosinolates). The chemical investigation showed a different composition between the two collection zones. While the total amounts of phenolics and flavonoids of the two samples were quite the same, their high-performance liquid chromatography profiles were very different. In both samples, the most abundant aglycone was quercetin which accounted for 60% of total flavonoids. Nuclear magnetic resonance data analysis allowed the identification of two compounds: 3,5-dicaffeoylquinic and 4,5-dicaffeoylquinic acids which represented 6.67% and 15.94%, respectively, of the total amount of flavonoids in sample 1. In sample 2, these two acids were still present, but their percentages were much less (2.20% and 1.71%, respectively). As far as we know, this is the first report about the presence of dicaffeoylquinic acids in Capparis. With regard to glucosinolate content, sample 1 showed a higher content of glucosinolates. In both samples, glucocapparin was the most abundant compound. Antioxidant activity of the methanolic C. sicula extracts using diphenyl picrylhydrazyl, β-carotene bleaching test and oxygen radical absorbance capacity showed that the sample 2 was more active than 1. As regards the inhibition of NO production, the extracts from sample 2 were more active than those from sample 1.