Abstract

Background: Boswellic acids are the main constituents of Boswellia serrata gum. These comprise of four pentacyclic triterpenes, 11-keto-β-boswellic acid (KBA) being one of them.

Objectives: Comparing the extraction efficiency of KBA through microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE) followed by optimizing the extraction process using response surface methodology (RSM) and validation of HPTLC.

Methods: UAE and MAE of KBA were carried out employing methanol as an extracting solvent. To figure out the better mode of extraction, single factorial experiments were conducted for further optimization. Design expert software was used for optimization purposes where solvent to drug ratio, extraction temperature and extraction time were taken as input variables. Quantification of KBA in each extract was done through High-Performance Thin Layer Chromatography (HPTLC), and the method was validated as per International Council for Harmonization (ICH) guidelines.

Results: UAE stood out to be a better mode of extraction for KBA. Solvent to drug ratio of 20.42 mL/gram, extraction temperature of 44.01°C and extraction time of 11.54 minutes were established as optimum conditions, which yielded 8.44%w/w of KBA. Regarding HPTLC, the Rf value of KBA was measured, and the correlation coefficient was calculated from the standard curve. Accuracy, precision and recovery were found within limits.

Conclusion: From this study, it was concluded that a non-thermal method is a better choice of extraction for KBA. All the input variables significantly affected KBA content, which was confirmed by model fitting. Moreover, the HPTLC method was developed for the quantification of KBA, which was found to be accurate, reliable and highly sensitive.

Keywords: 11-keto-β-boswellic acid, Boswellia serrata, ultrasound-assisted extraction, response surface methodology, HPTLC, Indian olibanum.