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Methanol extracts from 21 grain samples were subjected to an in vitro screening for their growth-promoting and inhibitory activities towards Bifidobacterium adolescentis, B. longum, B. bifidum, Clostridium perfringens, Escherichia coli and Lactobacillus casei using spectrophotometric and paper disc agar diffusion methods under O₂ free conditions. The responses varied with both bacterial strain and grain species. Among the grain extracts, the extracts of Fagopyrum esculentum, Ischaemum crassipes and Setaria italica enhanced the growth of lactic acid bacteria in carbon-free source medium. This growth-promoting effect was most pronounced with L. casei among the lactic acid bacteria examined. Additionally, all seed extracts did not adversely affect the growth of the tested lactic acid bacteria. In the growth-inhibitory effect, the extracts of F. esculentum and Perilla frutescens var. japonica inhibited C. perfringens and E. coli. These results may be indications of the responses of the grain extracts on human intestinal bacteria.
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