Evaluation of the Antioxidant Power and Secondary Metabolites Contents of the Crude Compounds of Talinum triangulare (Talinaceae)

Talinum triangulare is a food plant recognized for its nutritional properties and therapeutic virtues. This plant is used in particular in Daloa (Central-West Ivory Coast) by naturotherapists, for the treatment of malaria. This study aimed to evaluate the antioxidant activity of extracts and fractions of Talinum triangulare leaves and to determine their content of secondary metabolites. Two methods in vitro were used for this evaluation: reduction of the 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH) and reduction of the ABTS+ cation radical (2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid). The results show that the IC50 could not be determined for the 70 % aqueous and hydro-ethanolic extracts with the DPPH test, while it was respectively 0.9 and 2.3 mg/mL for the fractions dichloromethane and aqueous. Regarding the ABTS+ radical-cation reduction test, the dichloromethane fraction showed a higher percentage of inhibition (41.59 %) compared to the aqueous fraction (40.59 %), while the aqueous fraction was a little more important than the hydro-ethanolic extract at 70 % (38.29 %). Among the four compounds tested, only the aqueous extract presented a relatively low percentage of inhibition (25.51 %). Spectrophotometric analysis revealed the presence of various phenolic compounds, such as flavonoids, polyphenols and total tannins, at varying concentrations. These results could support the traditional use of Talinum triangulare in the treatment of malaria.