In vitro activity of natural honey alone and in combination with curcuma starch against Rhodotorula mucilaginosa in correlation with bioactive compounds and diastase activity

Objective:To evaluate the in vitro activity and synergism of the combinations of natural honey and curcuma starch against Rhodotorula mucilaginosa in correlation with total phenolic, flavonoid contents, and diastase activity. Methods:The Folin-Ciocalteu test was used to determine the total polyphenols content and the flavonoid content was analyzed using by the aluminum chloride method. The antifungal activity of the natural honey, determined by an agar well diffusion assay and agar incorporation method. Results:Total phenolic content varied from (63.93±0.11) to (95.36±6.08) mg GAE/100 g honey as gallic acid equivalent. Total flavonoids content varied from (5.41±0.04) to (9.94±0.54) mg CE/100 g. Diastase activity values were between (7.3±2.8) and (26±2.8). The zone inhibition diameter for the six honey samples without starch ranged between 6 and 20 mm. When starch was mixed with honey and then added to well, a zone inhibition increase diameter 7 and 21 mm. The percentage increase was noticed with each variety and it ranged between 5% and 62.5%. The minimal inhibitory concentrations for the six varieties of honey without starch against Rhodotorula mucilaginosa ranged between 28%and 36%(v/v). When starch was incubated with honey and then added to media, a minimal inhibitory concentration drop has been noticed with each variety. It ranged between 6.66%and 20%(w/v). No significant correlation was established between diastase activity and bioactive compounds. Conclusions:The mixture of curcuma starch and honey could lead to the development of new combination antibiotics against Rhodotorula infections.

Synergistic action of starch and honey against Candida albicans in correlation with diastase number

To evaluate the synergistic action of starch on the antifungal activity of honey, a comparative method of adding honey with and without starch to culture media was used. Candida albicans has been used to determine the minimum inhibitory concentration (MIC) of five varieties of honey. In a second step, lower concentrations of honey than the MIC were incubated with a set of concentrations of starch added to media to determine the minimum synergistic inhibitory concentration (MSIC). The MIC for the five varieties of honey without starch against C. albicans ranged between 40 percent and 45 percent (v/v). When starch was incubated with honey and then added to media, a MIC drop has been noticed with each variety. It ranged between 7 percent and 25 percent. A negative correlation has been established between the MIC drop and the diastase number (DN).

Para avaliar a ação sinergística do amido na atividade antifúngica do mel, utilizou-se um método comparativo de adição ou não de mel ao meio de cultura com e sem amido. Cândida albicans foi utilizada para determinar a Concentração Inibitória Mínima (CIM) de cinco variedades de mel. Na etapa seguinte, determinou-se a Concentração Inibitória Sinergística Mínima (CISM) empregando-se méis em concentração abaixo da CIM incubados com amido em diferentes concentrações.