Quantification of AKBA in Boswellia sacra Using NIRS Coupled with PLSR as an Alternative Method and Cross-Validation by HPLC.

INTRODUCTION: 3-O-Acetyl-11-keto-ß-boswellic acid (AKBA), one of the pentacyclic triterpenoids, is the main biologically active constituent in the resin of Boswellia sacra and has received significant pharmacological interest in recent years. OBJECTIVE: It was aimed to develop a robust method to quantify the AKBA content in methanolic extracts of different parts of B. sacra plants and in various fractions of its resin exudates through near-infrared spectroscopy (NIRS) coupled with partial least squares regression (PLSR). MATERIAL AND METHODS: The near-infrared (NIR) spectra were used to measure the AKBA standards and B. sacra samples at a wavelength range between 700 and 2500 nm in absorption mode. A PLSR model was built from the obtained spectral data using 70% of the AKBA working standard solutions (training set), ranging from 0.1 ppm to 100 ppm. The final PLSR showed a R2 value of 99% with a root mean square error of cross-validation (RMSECV) value of 0.39% and a R2 value of 99%. RESULTS: The results showed that a 50% CHCl3 /n-hexane sub-fraction has the highest concentration of AKBA (14.8%), followed by 55% CHCl3 /n-hexane (13.6%), and 40% CHCl3 /n-hexane (6.1%). CONCLUSION: As the results achieved with the proposed NIRS methodology are in close agreement to the results of AKBA analysis using HPLC, we suggest that our proposed NIRS method is a fast alternative and non-destructive method for the analysis of AKBA in different samples of B. sacra. Copyright © 2017 John Wiley & Sons, Ltd.