Anti-fungal effect of berberine on Candida albicans by microcalorimetry with correspondence analysis

Using a LKB-2277 bioactivity monitor, stop-flow mode, the power-time curves of Candida albicans growth at 37 °C affected by berberine were measured. The check experiments were studied based on agar cup method to observe the inhibitory diameter and serial dilution method to determine the minimal inhibitory concentration (MIC) of berberine on C. albicans growth. By analyzing the quantitative thermogenic parameters taken from the power-time curves using correspondence analysis (CA), we could find that berberine at a low concentration (5.0 μg mL-1) began to inhibit the growth of C. albicans and at a high concentration (75.0 μg mL-1) completely inhibited C. albicans growth. The anti-fungal activity of berberine could also be expressed as half-inhibitory concentration IC50, i.e., 50% effective in this inhibition. The value of IC50 of berberine on C. albicans was 34.52 μg mL-1. The inhibitory diameters all exceeded 10 mm in test range and the MIC was 500 μg mL-1. Berberine had strong anti-fungal effect on C. albicans growth. This work provided an important idea of the combination of microcalorimetry and CA for the study on anti-fungal effect of berberine and other compounds. Compared with the agar cup method and serial dilution method, microcalorimetry not only offered a useful way for evaluating the bioactivity of drugs, but also provides more information about the microbial growth and all this information was significant for the synthesis and searching of antibiotics. © 2009 Akadémiai Kiadó, Budapest, Hungary.