Analysis of boswellic acids in dietary supplements containing Indian frankincense (Boswellia serrata) by Supercritical Fluid Chromatography

Advances and Challenges in the Analysis of Boswellic Acids by Separation Methods

Boswellia resin is an exudate from the cut bark of Boswellia trees. The main constituents of pharmacological interest are boswellic acids (pentacyclic triterpenoids), namely α-boswellic acid, β-boswellic acid, 3-O-acetyl-α-boswellic acid, 3-O-acetyl-β-boswellic acid, 11-keto-β-boswellic acid, and 3-O-acetyl-11-keto-β-boswellic acid. Nowadays, dietary supplements with Boswellia serrata extract are used in the treatment of inflammatory joint diseases. Additionally, the constituents of Boswellia resin have shown potential for the treatment of other chronic inflammatory diseases and various types of cancer. Separation methods including ultra/high-performance liquid chromatography, gas chromatography, thin layer chromatography, supercritical fluid chromatography, and capillary electrochromatography coupled with UV or MS detection have been used for the determination of boswellic acids in various matrices (mostly plant material and biological samples). This review aims to provide a comprehensive summary of these separation methods, offering a critical discussion of their strengths and limitations in the analysis of boswellic acids. The knowledge of various separation methods plays a pivotal role in the quality control of herbal dietary supplements and the monitoring of the metabolism and pharmacokinetics of their constituents. The approaches based on metabolomics and network pharmacology represent new ways of fingerprinting secondary metabolites in Boswellia resin increasing the comprehensiveness of the output of these methods resulting in safer dietary supplements.

Chromatographic speed classification for liquid chromatography using average theoretical peak time (ATPT)

BACKGROUND

The development of analytical techniques in the field of liquid chromatography has brought new frontiers in performance and analytical speed for the technique. The proper evaluation of the analytical boundaries achieved with those developments was not addressed in the literature, since different liquid chromatography (LC) techniques have not yet received any classification regarding their chromatographic speed. Defining chromatographic analysis speed based simply on analysis time is an outdated concept since it is sample and analyte-dependent. In this context, the application of the Average Theoretical Peak Time concept (ATPT) is proposed as a unified metric for chromatographic speed classification.

RESULTS

This metric was evaluated using PCA analysis in a group of more than 50 publications, which generated the classification of LC methods in normal, high, hyper, and ultra-high-speed separations using ATPT. Normal speed (ATPT values greater than 18000 ms/peak) was found in HPLC, nano-LC, SFC, and CEC methods. Therefore, high-speed methods (ATPT values between 4000 and 18000 ms/peak) were found in UHPLC techniques, while LC × LC methods presented higher ATPT values between 1000 and 4000 ms/peak being classified as hyper-speed separations. ATPT can also be used as an optimization parameter, since older methods show higher ATPT values, while recent published papers show lower values of this metric. This behavior is justified due to the improvement of the LC methods over the years.

SIGNIFICANCE

This work fulfills the gap in chromatographic definitions and metrics, regarding analytical speed in one-dimensional and multidimensional liquid chromatographic techniques and shows that ATPT metrics is a robust parameter that can be used to classify the separation speed as well as a metric to evaluate the LC Method optimization. It also corrects the historical application of separation time as a metric for chromatographic speed.