Berberine is an alkaloid found in various plants, including goldenseal, barberry, oregon grape, and gold-thread. There is evidence to suggest that berberine demonstrates antimicrobial activity against bacteria, yeast, fungi, protozoans, viruses and helminths (worms) (Yu, Kim, Cha, Kim, Lee, Choi & You, 2005). In a recent study, researchers from the Department of Food and Nutrition, at Kunsan National University, investigated the antimicrobial activity of berberine against methicillin resistant staphylococcus aureus (MRSA) (Yu, Kim, Cha, Kim, Lee, Choi & You, 2005). MRSA is a bacterium responsible for several difficult to treat infections in humans. Individuals at risk of developing this bacterium include, hospital patients, prison inmates, people in contact with live-food producing animals, athletes and children. In the foregoing study it was found that 1 to 50 mg/mL of berberine had a notable effect on all tested strains of methicillin resistant staphylococcus aureus when used in isolation and in combination with ampicillin and oxacillin antibiotics.
Yu, H.H., Kim, K.J., Cha, J.D., Kim, H.K., Lee, Y.E., Choi, N.Y. & You, Y.O. Antimicrobial activity of berberine alone and in combination with ampicillin or oxcillin against methicillin-resistant Staphylococcus aureus. Journal of Medicinal Food, 8, 4, 454-461.