Phytotoxicity, antioxidant activity and chemical profile of aqueous extracts from Moroccan caper ( Capparis spinosa L.)

Due to its therapeutic and pharmaceutical benefits as well as its culinary applications, caper (Capparis spinosa L.) is quite interesting. This study aimed to evaluate some biological activities of the aqueous extracts of Capparis spinosa L. leaves, including the phytotoxic effect, antioxidant capacity, and the determination of total phenolic and flavonoid contents. The germination bioassay of the cress seeds (Lepidium sativum L.) was used to evaluate the phytotoxic effect. In addition, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical was used as a determinant of antioxidant capacity. The results obtained showed an important antioxidant capacity with an IC50 of 0.212 +/- 0.096 mg/mL. Also, a total phenolic content of 116.3 +/- 0.06 mg GAE/g DM and 18.9 +/- 0.08 mg RE/g DM for flavonoids were obtained. In addition, the extract showed a very significant (p < 0.001) dose-dependent inhibitory effect on the germination and root length of Lepidium sativum L. seeds. The qualitative study carried out by HPLC measurement allowed the detection of chlorogenic acid (3.2 %), vanillin (1.3 %), rutin (1.2 %), and some quercetin derivatives (6.9 %). The results obtained in this study revealed the potential of caper in bioactive molecules. In addition, it could be a natural bioactive product for therapeutic purposes, such as the prevention of oxidative stress and related disorders.