Optimization of ethanol based extraction of phenolics from Ocimum sanctum flowers by response surface methodology

Abstract

Ocimum sanctum L. flowers have been reported to have various health benefits owing to its phenolic composition. However, the available phenolic compounds should be effectively extracted to efficiently utilize these flowers. This study was aimed to make use of response surface methodology (RSM), to simultaneously optimize the process parameters to obtain maximum yield of phenolics and anthocyanins along with maximum DPPH radical scavenging activity from O. sanctum flowers. Central composite design (CCD) was employed with four independent variables; solid:liquid ratio (XA), ethanol concentration (XB), temperature (XC) and time (XD) which were found to affect the response variables significantly and fit to the second order polynomial model. The results showed that the polynomial models for all responses were significant (p < 0.05) and did not show lack of fit and presented acceptable coefficients of determination. This indicates the suitability of the models for prediction purposes. The desirability function approach in the scale of 0–1 was used to determine the optimized conditions. The optimum process parameters obtained were XA; 1:35 (w/v), XB; 55%, XC; 44 °C and XD; 32 min. The experimental values obtained based on optimum extraction parameters agreed with the predicted values. The findings suggests the application of optimized parameters to acquire functionally active phenolics and anthocyanins from O. sanctum flowers using ethanol and make use of them in food and pharmaceutical industry.