Goldenseal - Scientific Background
Because clinical trials addressing the safety and effectiveness of goldenseal preparations are unavailable, current information refers to the actions of substances contained in goldenseal extracts rather than the extracts themselves.
Ingredients of goldenseal have antibiotic properties.
Studies and a few human studies show antibiotic activity of hydrastine, berberine, and related alkaloids. While no recent randomized controlled trials offer data on the safety or efficacy of goldenseal herbal preparations for internal use (Tyler 1994), some research has been done on the properties of the major alkaloids, berberine and hydrastine.
The effects of berberine and hydrastine appear to be similar (Leung and Foster 1996).
Berberine has antimicrobial activity.
Berberine sulfate inhibits the growth of streptococci and appears to prevent streptococci from sticking to host cells (Sun et al 1988).
A berberine extract was effective against tuberculosis bacilli that were resistant against multiple drugs that inhibit the growth of tuberculosis bacteria (Gentry et al 1998).
Berberine has antifungal activity.
Crude herbal preparations containing berberine have been used historically in China and Japan. At a concentration of 1 milligram/milliliter, berberine is effective against Candida albicans, a microbe that is a frequent cause of fungus infections. At lower concentrations, it is effective against a number of fungi, including C. tropicalis and C. glabrata (Nakamoto et al 1990).
At concentrations of 10 to 25 milligram/milliliter, berberine inhibits the growth of Alternaria, Aspergillus flavus, Asp. fumigatus, Candida albicans, Curvularia, Drechslera, Fusarium, Mucor, Penicillium, Rhizopus oryzae, and Scopulariopsis, which can also cause fungus infections (Mahajan et al, 1982).
Berberine is active against infection-causing amoebas (single-celled organisms).
Berberine appears to be almost as effective against Giardia lamblia as a standard treatment, metronidazole (Flagyl®). While metronidazole causes considerable side effects, the berberine group of children in this study had no side effects (Gupte 1975).
In another group of children, berberine was shown to be more effective than metronidazole in treating Giardia (Choudhry et al 1972).
In a test-tube study, berberine sulfate inhibited the growth of Entamoeba histolytica, Giardia lamblia, and Trichomonas vaginalis, all of which can cause dangerous infectious diseases (Kaneda et al 1991).
