Phytochemical Study and Evaluation of Antioxidant Power of Selective Tannic Extracts of Three Medicinal Plants of Ivorian Flora

This work is devoted to phytochemical study of tannic extracts from the leaves of Combretum paniculatum (CP), Mallotus oppositifolius (MO) and Ximenia americana (XA), three medicinal plants of Ivorian flora, used in traditional medicine against certain types of cancer. Qualitative analysis by phytochemical screening of these extracts, performed by means of TLC, revealed in addition to hydrolysable and condensed tannins, the presence of phenolic acids and flavonoids. Total tannin contents determined by permanganometry and spectrophotometry are respectively 41.03 ± 0.77% and 12.3648 ± 0.0004% for MO; 20.03 ± 0.44% and 11.7974 ± 0.0001% for XA; 18.76 ± 0.89% and 11.6026 ± 0.0008% for CP. Condensed tannin content in XA leaves (234.135 ± 0.003 µg ECT/mg) is considerably higher than in CP (37.731 ± 0.001 µg ECT/mg) and MO (19.082 ± 0.001 µg ECT/mg). All XA extracts (aqueous and ethyl acetate) have shown good antioxidant activity with CR50s which are lower than that of vitamin C (reference antioxidant). A correlative relationship was found between tannin content and antioxidant activity.