BACKGROUND: There are several synergistic methods available. However, there is a vast discrepancy in the
interpretation of the synergistic results. Also, these synergistic methods do not assess the influence the tested
components (drugs, plant and natural extracts), have upon one another, when more than two components are
METHODS: A modified checkerboard method was used to evaluate the synergistic potential of Heteropyxis natalensis,
Melaleuca alternifolia, Mentha piperita and the green tea extract known as TEAVIGO™. The synergistic combination
was tested against the oral pathogens, Streptococcus mutans, Prevotella intermedia and Candida albicans. Inhibition
data obtained from the checkerboard method, in the form of binary code, was used to compute a logistic response
model with statistically significant results (p < 0.05). This information was used to construct a novel predictive
RESULTS: Based on the predictive inhibition model for each microorganism, the oral pathogens tested were
successfully inhibited (at 100% probability) with their respective synergistic combinations. The predictive inhibition
model also provided information on the influence that different components have upon one another, and on the
overall probability of inhibition.
CONCLUSIONS: Using the logistic response model negates the need to ‘calculate’ synergism as the results are
statistically significant. In successfully determining the influence multiple components have upon one another and
their effect on microbial inhibition, a novel predictive model was established. This ability to screen multiple
components may have far reaching effects in ethnopharmacology, agriculture and pharmaceuticals.
The University of Pretoria holds a provisional South African patent (ZA2013/
06534) relating to the content of the manuscript. No financial benefits have
been received by the authors.