RESUMEN
Fluorescence of Calcofluor and Congo Red was observed in stained sections of sorghum grain (Sorghum bicolor (L.) Moench), especially in the sub-aleurone cells indicating the presence of mixed linkage beta-D-glucan. Relatively less fluorescence intensity was observed in the single layered (approximately 20 microns thick) aleurone. Alkali extracted beta-D-glucan (fraction 2) of sorghum showed 30% activation of rat peritoneal macrophages (in vitro) at 100 micrograms ml-1 concentration in 10 min. This activation was found mediated mainly through PLA2 pathway. A phagocytic index k of 0.102 +/- 0.008 was observed in vivo carbon clearance test in mice in the group treated with fraction 2. Accumulation of colloidal carbon particles in spleen and liver of mice was moderate in this group, compared to control.