The HPLC/DAD Fingerprints and Chemometric Analysis of Flavonoid Extracts from the Selected Sage (Salvia) Species

The results of spectrophotometric and HPLC/DAD analysis are discussed, and a comparison is made of selectively extracted flavonoid fractions derived from twenty six sage species belonging to the Salvia genus. The sage samples were harvested in the vegetation seasons 2007, 2008, and 2009. It was a goal of this study to find out which species contain the highest yields of flavonoids (recognized for their free-radical-scavenging activity), as those with the highest yields could be applied in official medicine. It was spectrophotometrically established that the four sage species can be recognized for their highest flavonoid levels, while the HPLC/DAD analysis pointed out to the four other species. The source of the discrepancy between the two evaluation approaches was discussed. Moreover, the HPLC/DAD fingerprints of the flavonoid fraction underwent a chemometric pre-treatment, and then the purified fingerprints were analyzed by means of Principal Component Analysis (PCA) for the differences in the harvesting period. A difference was revealed between the herbs harvested in the 2007 season, and those harvested in 2008 and 2009. The main source of this difference could be the seasonal weather variation and the relatively longest storage period with the plants harvested in 2007. 1. Introduction In spite of a vast number of the different species and a wide popularity of the plants belonging to the Salvia genus, relatively little attention has been paid to phytochemical analysis of these plants, prior to our own systematic research (e.g., [1–4]). In the course of the centuries, different sage species have gained the repute for their outstanding therapeutic, culinary, and decorative valor. However, the official European medicine recognizes just one sage species for its curative properties, which is Salvia officinalis. It is a well-known fact that the curative properties of many plants are due to the high contents of phenolics, which act as the free-radical scavengers. Thus, it became an objective of this study to analyze a selection of the different sage species popular in Central and South Europe (where they grow both in a natural habitat and as cultivars) and to fingerprint the flavonoid fraction present therein by means of HPLC/DAD. It was our intent to ultimately point out to these Salvia species, which might compete with S. officinalis in terms of the high levels of flavonoids. To this effect, we spectrophotometrically determined an overall content of flavonoids in the sage extracts which were selectively obtained following the pharmacopeial procedure [5].