Optimal Processing Conditions of Boswellia carteri Birdw. Using Response Surface Methodology

BACKGROUND: Boswellia carteri Bridw. is being widely used for its anti-inflammatory properties, as well as for wound healing, antimicrobial, and immunomodulatory properties, and boswellic acids (BAs) are considered to be the main active constituents. OBJECTIVES: To investigate optimal conditions of stir-baking process for the resin of B. carteri with vinegar of using response surface methodology (RSM). MATERIALS AND METHODS: The concentration of acetic acid, heating temperature, and heating time were set as influential factors, and the yields of chemical compounds were the response values which were optimally designed by a Box–Behnken design. The amounts of 11-keto-β-boswellic acid (KBA) and α-boswellic acid (αBA) in B. carteri resin were quantified using high-performance liquid chromatography analysis. RESULTS: Maximum amounts of KBA and αBA in B. carteri resin were obtained using 6% acetic acid for 10 min at 90°C in preliminary test. Two factor interactions, such as acetic acid concentration–heating temperature and heating temperature–heating time, were significantly observed by multiple regression analysis. Optimal processing conditions from RSM were 5.83% for acetic acid concentration, 9.56 min for heating time, and 89.87°C for heating temperature. Under the modified conditions, the experimental value of the response was 11.25 mg/g, which was similar to the predicted value. CONCLUSIONS: The results suggest that the optimal conditions for the stir-baking process of B. carteri resin were determined by RSM, which was reliable and applicable to practical processing of herbal medicine. SUMMARY: The resin of Boswellia carteri was macerated in aqueous acetic acid and heated using an oven for stir baking process. The interaction between heating temperature and heating time was the most significant. Optimal conditions for processing B. carteri resin were determined as 5.83% acetic acid, 9.56 min for heating time, and 89.87°C for heating temperature. Abbreviations used: BAs: Boswellic acids; KBA: 11 keto β boswellic acid; αBA: α boswellic acid; BBD: Box–Behnken design; RSM: Response surface method; HPLC: High performance liquid chromatography; LOD: Limits of determination; LOQ: Limits of quantification; RSD: Relative standard deviation; ANOVA: Analysis of variance.