Abstract

COMPARATIVE STUDY OF THE PHENOLIC COMPOUNDS OF FOUR VARIETIES OF SORGHUM (SORGHUM BICOLOR (L) MOENCH) CULTIVATED IN BURKINA FASO

Crépin I. Dibala*, Raymond P. Barry, Kiessoun Konaté and Mamoudou H. Dicko

ABSTRACT

Sorghum bicolor (Poaceae) is the oldest cultivated plant in the world. It grows in dry, sodden or high salinity soil and is a heat-tolerant plant considered to hold the most important rate of phenolic components. The bioactive composites of the stem, the leaf, the grains, the seeds and the glumes for four Sorghum bicolor species such as Framida, Sariaso 19, Sariaso 14 and Gnossiconi were extracted by ethanolic hydrochloric acid maceration and then assayed using spectrophotometric methods. The DPPH and ABTS methods were used to assess the antioxidant properties of these studied species. All organs (stems, leaves, girdles, grains and husks) presented some contents in compounds variable polyphénolics of a variety to the other. The contents in total phenolics were of 14,53 ± 0,25 mg GAE/100 mg of dry matter in the stems of Sariaso 14, of 27,43 ± 0.21mg GAE/100 mg of dry matter in the leaves of Gnossiconi, of 42,72 ± 4,03 mg GAE/100 mg of dry matter in the girdles of Framida, of 17, 17 ± 1,02 mg EAG/100 mg of dry matter in the grains of Sariaso 19 and 14,48 ± 0,26 mg GAE/100 mg of dry matter in the husks of Sariaso 14. For the contents in total flavonoid, the girdles of Framida (8,87 ± 4,03 mg QE/100 mg) would contain some in strong content, followed of the Stems of Framida (6,64 ± 0,38 mg QE/100 mg) and of the leaves of Sariaso 19 (4,54 ± 0,73 mg QE/100 mg). An interesting antioxidant activity was found for the different organs of all the four species using both DPPH and ABTS methods. Indeed, the ABTS method showed the contents of 8.26 ± 0.35 mg EAA / g and 10.57 ± 0.20 mg EAA / g for the stems and leaves of Framida respectively. Around 98.49 % of Framida’s leaves, 89.06 % of Gnossiconi’s stems and its grains presented the best antioxidant activities using the DPPH method as well. These results suggest that Sorghum bicolor organs constitute an important source of polyphenolic composites and would own antioxidant activity.

Keywords: Sorghum bicolor, stem, leaf, grains, glume, seeds, phenolic composites, antioxidant.