Identification of medicinal herbs in Asteraceae and Polygonaceae using an electrochemical fingerprint recorded using screen-printed electrode

Authentication and identification of Lamiaceae family with cyclic voltammetry fingerprint-PCA-LDA and determination of the used phenolic contents for classification using chromatographic analyses

Todays, it is essential to evaluate and check the quality of herbal medicines in to protect the public health. As medicinal plants, the extracts of labiate herbs are used directly or indirectly to treat a variety of diseases. Increase in their consumption has led to the fraud in herbal medicines. Hence, modern accurate diagnostic methods must be introduced to differentiate and authenticate these samples. Electrochemical fingerprints have not been evaluated for their capacity to distinguish and classify various genera within a family. Since it is essential to classify, identify, and distinguish between these closely related plants in order to guarantee the quality of the raw materials, the authenticity and quality of 48 dried and fresh Lamiaceae samples, which include Mint, Thyme, Oregano, Satureja, Basil, and Lavender with various geographic origins, were examined. The present study focused on (a) classification and authentication Labiate herbs extracts and (b) identification of active compounds in samples by Gas chromatography and HPLC methods. This was accomplished using principal component analysis (PCA) and PCA-linear discriminate analysis (PCA-LDA). The results of the clustering revealed that PCA-LDA categorized mint species more accurately than PCA. In addition to certain flavonoids including ferulic acid, apigenin, luteolin, and quercetin, HPLC and GC analysis of the ethanolic extract revealed the presence of phenolic acids such as rosmarenic acid, methyl rosmarenate, caffeic acid, cinnamic acid, and chlorogenic acid. Comparing results of PCA-LDA with chromatographic analysis show that the authentication and detection of fraud samples were correctly performed using chemometyrics technique based on CV fingerprints. Even, there was no need to completely identify components of the mint samples.

Analysis of Electrochemically Active Substances in Malvaceae Leaves via Electroanalytical Sensing Technology for Species Identification

Electrochemical analysis has become a new method for plant analysis in recent years. It can not only collect signals of electrochemically active substances in plant tissues, but can also be used to identify plant species. At the same time, the signals of electrochemically active substances in plant tissues can also be used to investigate plant phylogeny. In this work, we collected electrochemical finger patterns in Malvaceae leaves based on the established methodological strategy. After the second derivative treatment, the collected electrochemical fingerprints can show more obvious differences. Three different recognition models were used to attempt electrochemical fingerprinting. The results show that linear support vector classification can be used to identify species with high accuracy by combining the electrochemical fingerprint signals collected in the phosphoric acid buffer solution and acetic acid buffer solution. In addition, the fingerprint information collected by the electrochemical sensor is further used for phylogenetic investigation. The 18 species were divided into three clusters. Species of the same genus have been clustered together. Dendrogram obtained by electrochemical fingerprinting was used to compare previously reported results deduced from morphological and complete chloroplast genomes.

Electrochemical fingerprinting sensor for plant phylogenetic investigation: A case of sclerophyllous oak

Electrochemical fingerprinting can collect the electrochemical behavior of electrochemically active molecules in plant tissues, so it is regarded as a new plant analysis technology. Because the signal of electrochemical fingerprinting is positively correlated with the amount and type of electrochemically active molecules in plant tissues, it can also be used to reflect genetic differences between different species. Previous electrochemical fingerprinting techniques have been frequently used in phylogenetic studies of herbaceous plants. In this work, 19 Quercus species (17 evergreen or semi evergreen species and 2 deciduous species) were selected for investigation. The results indicated the electrochemical fingerprint of some species share similar features but can be distinguished after changing the recording condition (extraction solvent and electrolyte). The two sets of electrochemical fingerprint data can be used to construct different pattern recognition technology, which further speeds up the recognition efficiency. These electrochemical fingerprints were further used in phylogenetic investigations. The phylogenetic results deduced from electrochemical fingerprinting were divided mainly into three clusters. These can provide evidence for some of these arguments as well as new results.

Electrochemical-based quantitative fingerprint evaluation strategy combined with multi-markers assay by monolinear method for quality control of herbal medicine

BACKGROUND

Improving the quality control (QC) criterion of herbal medicine (HM) is an ongoing challenge. A rapid and convenient electrochemical analysis technique is now emerging as a promising application for HM QC. So far, extraction and analysis of the overall electroactive components is a key issue need to be solved to improve its application in integral HM QC.

PURPOSE

In this work, using compound liquorice tablets (CLQTs) as an example, we like to put forward a more reliable and accurate quantification method of multi-components for the precise QC of HM. Furthermore, we propose an electrochemical fingerprint-based data mining, extract and synthesis strategy for in-depth and comprehensive QC of HM, qualitatively and quantitatively.

METHODS AND DESIGN

Firstly, the electrochemical quantitative fingerprint of 54 batches of CLQTs from nine manufacturers were developed using B-Z oscillatory system. Secondly, eight characteristic parameters were recorded and compared among samples using intuitive information and PCA. Then, t_und was used to establish the correlation with sample dosage for determination of the relative content of overall electroactive components (Rc). The quantitative determination of five quality markers (Q-markers) were also performed using the novel method, called multi-markers assay by monolinear method (MAML). Finally, after using area integral calculus for electrochemical fingerprint, average linear quantitative fingerprint method (ALQFM) was successfully proposed to extract all latent characteristics for integral quality evaluation of samples.

RESULTS

The t_und and dosage showed a good correlation, by which the obtained Rc displayed different fluctuation among nine manufacturers. Moreover, the contents of five Q-markers obtained by MAML displayed no significant difference with the traditional quantification method. Samples evaluated by ALQFM manifested the integral information and were divided into eight quality grades. The deduced results of correlation between P_l with P_5C, Rc and P_A were more persuasive for demonstrating the reliability and integrity of ALQFM in quality evaluation of HM electrochemical fingerprint.

CONCLUSION

The study confirmed the idea that quantification of Q-markers combined electrochemical-based quality evaluation strategy could be used as a reliable method for HM QC qualitatively and quantitatively from point (precise) to face (integral).

Can Electrochemical Sensors Be Used for Identification and Phylogenetic Studies in Lamiaceae?

Electrochemical sensors have shown potential in recent years for plant species identification and phylogenetic studies. These works have been used to investigate the affinities of different species in many genera. However, the ability of electrochemical sensors to study relationships between different genera within a family has not been investigated. In this work, we selected 31 species in the Labiatae and 5 exotaxa as subjects to investigate the feasibility of electrochemical sensors at the genus level. The results show that electrochemical sensors are still very effective for the identification of these plants. Different pattern recognition techniques can make the identification more efficient. Also, the fingerprint profiles collected by the sensors can be used for phylogenetic studies of Labiatae. The phylogram divides all the species into five clusters, where the exotaxa are in one cluster. Species in the Labiatae are mainly distributed in four other clusters. Importantly, the different genera of species all showed close affinities, representing that electrochemical fingerprinting can well distinguish the affinities between the different genera. The results of this work demonstrate the great potential of electrochemical sensors in the study of plant phylogeny. Its application is not limited to the study at the species level, but can be extended to the genus level.