The In-vitro Antibacterial Effect of Colored Rice Crude Extracts against Staphylococcus aureus Associated with Skin and Soft-Tissue Infection

Due to increases in the resistance of bacteria to the existing antimicrobial agents, plants are being used as alternative sources for the development of safe, effective, and inexpensive new agents to treat and prevent bacterial infections. Recent studies have shown that rice (Oryza sativa L.), an important source of nutrients, consumed by most of the world’s population, can suppress some bacterial infections. There are many varieties of rice, e.g. white, brown, black, and red; however, the relationship between rice color and antibacterial properties remains unclear. In the present study, we investigated the antibacterial activity of colored-rice crude extracts from four different types of colored rice (Hom Nil, Neaw Dum, Mun Poo, and Sang Yod) against common bacteria causing skin and soft-tissue infections, such as Staphylococcus aureus, Streptococcus pyogenes, Enterococcus spp., Pseudomonas aeruginosa, and Escherichia coli. The results showed that all colored-rice crude extracts had antibacterial effects against S. aureus; and more notably, crude extracts of differently colored rice restricted diverse antibacterial activities. To our knowledge, this is the first report that provides a basic understanding of the antibacterial properties of colored rice against skin and wound pathogens. An understanding of these properties would be invaluable in the development of alternative, natural, and safe methods of controlling bacterial infections.