Antioxidant Properties of some Extracts from Adansonia digitata L. Using Two Different Automated Cell-Free Assays

Naturally occurring antioxidants can help fight many diseases that include oxidant-degenerative reactions such as cancer [1]. Many medicinal plant extracts and fractions have been proven as rich sources of antioxidant activities. In the present study the total alcoholic, ethyl acetate and water fractions of Adansonia digitata L. fruit pericarps were assessed for both radical scavenging and oxidant-reducing properties.

The evaluation of radical scavenging and oxidant reducing activities were carried out using automated, 96-well, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging [2] and FRAP (Ferric-reduction antioxidant power) assays [3] respectively. Results were expressed as Trolox ® equivalents in both assays.

In the DPPH assay, Adansonia total alcoholic extract and its two sub-fractions showed strong radical scavenging properies at low concentration (15µg/ml) giving Trolox ® equivalents in the order: ethylacetate fraction=water fraction > total alcoholic extract. In the FRAP assay, the three extracts produced FRAP activity in the order: ethylacetate fraction > total alcoholic extract > water fraction at final reaction concentration of 62.5µg/ml. The antioxidant activities shown in this study are consistent with a previous study [4] that revealed the occurrence of proanthocyanidins as major constituents in the total alcoholic extract. The results recommend extended study in cell-based assays to further elucidate the correlation of cell-free and cell-based systems in determination of the antioxidant potential of these plant extracts.

Acknowledgements: Egyptian Government; Prof. F M Hammouda, National Research Centre (Cairo, Egypt).

References: [1] Ames, B. N. et al. (1993) PNAS 90: 7915–22. [2] Nara, K. et al. (2006) Biosci. Biotechnol. Biochem.70: 1489–91. [3] Benzie I. F., Strain J. J. (1996) Anal. Biochem. 239: 70–6. [4] Shahat, A. A. (2006) Pharmaceutical Biol. 44: 445–50.