Mohamed I. Abou-Shoer

Application of Chemometrics in Authentication of Herbal Medicines: A Review

INTRODUCTION Herbal medicines (HM) and their preparations have been widely used for hundreds of years all over the world. However, they have not been officially recognised due to a lack of adequate or accepted research methodology for their evaluation. OBJECTIVE To present a concise overview of the recent applications of chemometrics in solving the ambiguity of herbal medicine authentication during the last two decades. METHODOLOGY Studies involving the applications of chemometric analysis in combination with different analytical methods were classified according to the method of analysis used including chromatographic (HPLC, GC and CE), spectroscopic (NMR, IR, UV and ICP) and genetic analysis (RAPD). The purpose of each of these studies was classified into one of three main categories: taxonomic discrimination, quality assessment or classification between plants of different geographic origins. RESULTS This review comprises over 150 studies, covering the past two decades, emphasising the significance of chemometric methods in the discrimination of many herbs from closely related species and from adulterants, based on the principal bioactive components and phytochemical diversity. Furthermore, the differentiation between varieties and hybrids was achieved in addition to the prediction of the active components by quantitative methods of analysis. Discrimination according to geographical origin and localities, processing methods, DNA profiling and metabolomics were also efficiently investigated. CONCLUSION Chemometric methods have provided an efficient and powerful tool for the quality control and authentication of different herbs.

A modern approach to the authentication and quality assessment of thyme using UV spectroscopy and chemometric analysis.

INTRODUCTION Recently, the fields of chemometrics and multivariate analysis have been widely implemented in the quality control of herbal drugs to produce precise results, which is crucial in the field of medicine. Thyme represents an essential medicinal herb that is constantly adulterated due to its resemblance to many other plants with similar organoleptic properties. OBJECTIVE To establish a simple model for the quality assessment of Thymus species using UV spectroscopy together with known chemometric techniques. The success of this model may also serve as a technique for the quality control of other herbal drugs. MATERIALS AND METHODS The model was constructed using 30 samples of authenticated Thymus vulgaris and challenged with 20 samples of different botanical origins. The methanolic extracts of all samples were assessed using UV spectroscopy together with chemometric techniques: principal component analysis (PCA), soft independent modeling of class analogy (SIMCA) and hierarchical cluster analysis (HCA). RESULTS The model was able to discriminate T. vulgaris from other Thymus, Satureja, Origanum, Plectranthus and Eriocephalus species, all traded in the Egyptian market as different types of thyme. The model was also able to classify closely related species in clusters using PCA and HCA. The model was finally used to classify 12 commercial thyme varieties into clusters of species incorporated in the model as thyme or non-thyme. CONCLUSION The model constructed is highly recommended as a simple and efficient method for distinguishing T. vulgaris from other related species as well as the classification of marketed herbs as thyme or non-thyme.

Terpenes and flavonoids from an Egyptian collection of Cleome droserifolia.

Four new sesquiterpene derivatives have been isolated from the aerial parts of Cleome droserifolia. Their structures were established as 6-di(7-hydroxy, 1, 5-epoxy germacrane) (2), 4(15)-guaiane-6-ol (3), 7α-germacra-1(10), 4(15)-diene-5β, 6α-diol (4) and 4,7,8-eudesma-triol (5). In addition, a new dolabellane diterpene derivative with the naturally rare peroxy function was identified as methyl ester of 2,18-O-diacetyl-16-O-(3-hydroxy-3-methylglutaryl)-7-hydroperoxydolabella-3,8(17)diene-2,16,18 triol (7). Two known flavonoid derivatives, pinocembrin (6) and quercetin-3-glucoside,7-rhamnoside (1) were isolated from the same source. Structures were established by spectroscopic data.

Authentication of Monofloral Yemeni Sidr Honey Using Ultraviolet Spectroscopy and Chemometric Analysis

This work describes a simple model developed for the authentication of monofloral Yemeni Sidr honey using UV spectroscopy together with chemometric techniques of hierarchical cluster analysis (HCA), principal component analysis (PCA), and soft independent modeling of class analogy (SIMCA). The model was constructed using 13 genuine Sidr honey samples and challenged with 25 honey samples of different botanical origins. HCA and PCA were successfully able to present a preliminary clustering pattern to segregate the genuine Sidr samples from the lower priced local polyfloral and non-Sidr samples. The SIMCA model presented a clear demarcation of the samples and was used to identify genuine Sidr honey samples as well as detect admixture with lower priced polyfloral honey by detection limits >10%. The constructed model presents a simple and efficient method of analysis and may serve as a basis for the authentication of other honey types worldwide.