Correlation Mechanism Between “Traditional Flavor Profiles-Chemical Composition” of the Eerdun Wurile Basic Formula Based on Electronic Tongue and UPLC-HRMS

OBJECTIVE To combine the electronic tongue taste system with UPLC-HRMS technology to elucidate the taste characteristics and corresponding chemical component categories of the Mongolian medicine Eerdun Wurile basic formula(EWB), and to preliminarily establish its “taste-component” relationship.

METHODS Using Margarita, Glycyrrhizae Radix et Rhizoma, Inulae Radix, Aucklandiae Radix, Aquilariae Lignum Resinatum, Bovis Calculus, Piperis Fructus, Euphorbiae Humifusae Herba, Bubali Cornu Concentratum Pulvis and Moschus as raw materials, EWB was prepared in accordance with the Inner Mongolia Mongolian Medicine Preparation Standards and the Inner Mongolia Mongolian Medicine Decoction Piece Processing Standards(2020 Edition). Subsequently, the EWB extract(EWB extracts, EWT) was obtained through reflux extraction, vacuum recovery‌ and freeze-drying. Then, according to the grouping, each medicinal material was taken, mixed with deionized water, and subjected to ultrasonic oscillation or decoction for 30 min. After filtration, the supernatant was collected as the test solution for the electronic tongue. The chemical components and their classifications in EWB were analyzed using UPLC-HRMS and the NPClassifier natural product classification method.

RESULTS The electronic tongue results showed that the decoction method, compared with the ultrasound method, enhanced the bitterness of Glycyrrhizae Radix et Rhizoma while reducing the bitterness intensity of Moschus, and attenuated the umami taste of Glycyrrhizae Radix et Rhizoma, Inulae Radix, Aucklandiae Radix, Aquilariae Lignum Resinatum, Piperis Fructus and Euphorbiae Humifusae Herba(P<0.05). The decoction-treated EWB group(SEWB) exhibited a newly emerged astringency, increased bitterness, umami, and bitter aftertaste, and decreased saltiness, astringent aftertaste, and umami aftertaste compared with the decoction-treated Eerdun Wurile group(SEW)(P<0.05). Furthermore, compared with the ultrasound-treated EWB group(CEWB), the SEWB showed enhanced intensities of bitterness, astringent aftertaste, and bitter aftertaste, also newly detected a specific astringency response value, while saltiness and umami response values exhibited a decreasing trend(P<0.05). Chemical composition analysis identified 2033 characteristic compounds in EWB, which were classified by NPClassifier mainly into three major biosynthetic pathways: Shikimate ester-phenylpropanoids(27%), terpenoids(22%), and alkaloids(20%). A total of 42 compounds, including glycyrrhizin, 18β-glycyrrhetinic acid, agarotetrol, and piperlonguminine, were annotated in the base peak chromatogram.

CONCLUSION This study elucidates that after decoction, EWB exhibits bitterness, astringency, saltiness, umami, and aftertaste characteristics, with its chemical components mainly comprising shikimate ester-phenylpropanoids, terpenoids, and alkaloids. The possible correlations between the “traditional taste” and chemical composition of EWB are preliminarily discussed.