Determination of Bitterness of Andrographis Herba Based on Electronic Tongue Technology and Discovery of the Key Compounds of Bitter Substances.

Xiao Zhang,Hongwei Wu,Liying Tang,Yaqi Lu,Hongjun Yang,Zhuju Wang,Xiankuo Yu,Hanyan Luo,Zhiyong Li,Xin Li

doi:10.3390/molecules23123362

Abstract

Andrographis Herba (AH), the dry aerial segments of Andrographis paniculata (Burm.f.) Nees, is a common herbal remedy with bitter properties in traditional Chinese medicine (TCM) theory. Although bitterness is one of the features representing Chinese medicine, it has not been implemented as an index to assess the quality and efficacy of TCM because of peoples’ subjectivity to taste. In this study, 30 batches of AH with different commercial classifications (leaves, stems, or mixtures of both) were collected. Bitterness of AH was quantified by electronic tongue technology. Meanwhile, chemical compositions were characterized through establishing high-performance liquid chromatography fingerprints. The result indicated that the radar curves of the bitterness from different AH commercial classifications displayed different taste fingerprint information. Based on six taste factors, a Principal Component Analysis (PCA) score three-dimensional (3D) plot exhibited a clear grouping trend (R2X, 0.912; Q2, 0.763) among the three different commercial classifications. Six compounds (Peaks 2, 3, 4, 6, 7, 8) with positive correlation to bitterness were discovered by a Spearman correlation analysis. Peaks 2, 6, 7, 8 were identified as andrographolide, neoandrographolide, 14-deoxyandrographolide, and dehydroandrographolide, respectively. The electronic tongue can be used to distinguish AH samples with different commercial classifications and for quality evaluation.

Highlights

Andrographis Herba (AH, Chuan Xinlian in Chinese) is derived from the dry aerial segments of Andrographis paniculata (Burm.f.) Nees, and it has been used in folk medicines for the treatment of fever, common colds, diabetes, hepatitis, skin infections, snake bites, hypertension, and other diseases in several Asian countries, including China, India, and Thailand [1]
Electronic tongue technology was firstly applied to assess the bitterness of AH
The results implied that electronic tongue had the ability to distinguish the bitterness among different commercial classifications

Summary

Introduction

Andrographis Herba (AH, Chuan Xinlian in Chinese) is derived from the dry aerial segments of Andrographis paniculata (Burm.f.) Nees, and it has been used in folk medicines for the treatment of fever, common colds, diabetes, hepatitis, skin infections, snake bites, hypertension, and other diseases in several Asian countries, including China, India, and Thailand [1]. According to Traditional Chinese Medicine (TCM) theory, the properties and actions of Chinese herbs refer to their nature and effects relating to treatments. These properties include the “five flavors”, which are tastes composed of pungent, sweet, sour, bitter, and salty, which are high-level summary of the clinical efficacy [5].

Methods

Results

Conclusion