Synergistic effects of Iranian seaweed compounds for anticandidal properties and optimization by Response Surface Methodology

An optimization procedure was applied to investigate the anticandidal property of four different Iranian seaweed extract compositions. Response Surface Methodology (RSM) with the four levels- three–factor Box–Behnken design, including Gracilaria arquata concentration (X1), Nizimudidnia zanardini concentration (X2), Cystoceria indica concentration (X3) and Padina australis concentration (X4), was used to screen for anticandidal property screening. Multiple regression analysis of data showed that the coefficient determination (R^2) was appropriate for the second-order model. The anticandidal property of the seaweed extract composition of 10 mg ml^-1 G. arquata extract, 5 mg ml^-1 N. zanardini extract, 4.5 mg ml^-1 C. indica extract and 2 mg ml^-1 P. australis extract was found to be optimal. Under the optimized composition, the Candida albicans growth inhibition zone was 26.23 mm. The experimental yield was well matched with the predicted yield.