Metabolic Fingerprinting of Different Sideritis Taxa Infusions and Their Neurogenic Activity.

Over the last years, Sideritis extracts were shown to improve memory. However, their potential to promote the generation of new neurons, starting with the neuronal differentiation of neural stem cells, remains unexplored. Therefore, the present study aimed to evaluate the neurogenic effects of different Sideritis infusions in neural stem and precursor cells and their impact on cell viability. Moreover, the metabolic fingerprints were recorded using LC-DAD, LC-HRESIMS, and GC-MS. The neurogenic potential of infusions of the eight Sideritis taxa tested was as potent as the classical neuronal inducer combination of retinoic acid and valproic acid. Further cytotoxicity assays revealed that the IC50 values of the extracts were between 163 and 322 µg/mL. Hierarchical cluster analyses of the metabolic fingerprints unveiled that the two Sideritis taxa with the lowest IC50 values were the most divergent in the analytical techniques used. As the analysis focused on polyphenols, it is reasonable to assume that these compounds are responsible for the effect on the cell viability of SH-SY5Y neuroblastoma cells. This study is the first report on the neurogenic potential of Sideritis taxa and might support the use of Sideritis herbal preparations in the context of neurodegenerative diseases.

Genus Sideritis, section Empedoclia in southeastern Europe and Turkey - studies in ethnopharmacology and recent progress of biological activities.

BACKGROUND: Over the last two decades there has been a substantial increase of the number of studies on the species of genus Sideritis. Species of section Empedoclia, occurring in the Eastern Mediterranean region and in part of Western Asia possess some remarkable characteristics and are known as valuable medicinal plants used by local people in the traditional medicine and for herbal tea. The objective of the review is to make a survey on the recent studies on the ethnopharmacology and biological activity of the species in Southeastern Europe and in Turkey, which is the center of distribution and their main occurrence. MAIN BODY: The review focuses on the ethnopharmacology and biological activities of the species of interest. The survey revealed that a total of 47 species belonging to section Empedoclia have been studied either in ethnopharmacological aspect, or in relation to their biological activities, or both. Most species have been used traditionally by the local people as herbal tea or for treatment of various health problems, most frequently flu, cold and respiratory diseases. Sideritis species demonstrate numerous biological activities and are promising for use in the therapy of many diseases and health disorders. Antioxidant activity was found in 40 species, antimicrobial and antibacterial activity - in 27 species, anti-inflammatory - in 14 species, antifungal - in 8 species, cytotoxic - in 7 species. There were also some other, more specific biological activities, found in a few species, but considered promising for further studies and application. SHORT CONCLUSION: The species of genus Sideritis, section Empedoclia have been used by local people as herbal tea and in traditional medicine since long time ago. People are taking advantage of the high species diversity and are aware of their useful properties. Much more information is available on the biological activities of the target species than on their traditional uses. Most species demonstrate various biological activities and are of substantial interest for further studies on their pharmacological properties and their potential for pharmacy and medicine. Graphical abstract Schematic illustration of traditional uses and biological activities of some Sideritis species. Arrows with different colors represent biological activities of different species. The species and their corresponding color can be seen at the right part of the figure. The colors correspond also to the squares placed in the different parts of human body.

Comparative Chemical Composition and Antioxidant Properties of the Essential Oils of three Sideritis libanotica Subspecies.

The phytochemical composition of the essential oils of three Sideritis libanotica subspecies, namely S. libanotica ssp. libanotica, S. libanotica ssp. linearis and S. libanotica ssp. michroclamys, all collected in Lebanon, was analyzed by GC and GC-MS. The diterpene sideridiol was recognized as the main constituent of both S. libanotica ssp. libanotica (50.8%) and S. libanotica ssp. michroclamys (18.4%) oils, while hexadecanoic acid (10.5%) prevailed in S. libanotica ssp. linearis. The antioxidant activity of the oils was studied in two cell free systems by DPPH radical scavenging and ferric ion reduction (FRAP) assays; only S. libanotica ssp. linearis showed a moderate activity when assayed by the FRAP test (0.6 ± 0.01 mmol TE/mL).

DNA barcode ITS2 coupled with high resolution melting (HRM) analysis for taxonomic identification of Sideritis species growing in Greece.

Identification of genotypes in Sideritis is complicated owing to the morphological similarity and common occurrence of natural hybridisation within Sideritis species. Species- and genotype-specific DNA markers are very useful for plant identification, breeding and preservation programs. Herein, a real-time polymerase chain reaction (PCR) of ITS2 barcode region coupled with high resolution melting-curve (HRM) analysis was evaluated for an accurate, rapid and sensitive tool for species identification focusing on seven Sideritis species growing in Greece. The HRM assay developed in this study is a rapid and straightforward method for the identification and discrimination of the investigated Sideritis species. This assay is simple compared to other genotyping methods as it does not require DNA sequencing or post-PCR processing. Therefore, this method offers a new alternative for rapid detection of Sideritis species.

Aroma compounds of mountain tea (Sideritis scardica and S. raeseri) from western Balkan.

The composition of the volatile aroma components was defined in the dried and fresh aerial parts of Sideritis scardica Griseb. from R. Macedonia and S. raeseri Boiss. & Heldr. from R. Macedonia, Albania and Greece. Analysis was made by gas chromatography (GC/FID/MS) equipped with a headspace (HS) sampler. Thirty-two components (15 monoterpenes representing 33.2- 62.8% and 17 sesquiterpenes representing 25.2- 51.2% of the entire volatiles) were identified as aroma components of dried plant material of S. scardica. Thirty components {14 monoterpenes (19.3-74.2%), 2 alcohols (6.2- 38.4%) and 14 sesquiterpenes (18.2- 33.5%)} were identified as aroma components in the fresh aerial parts of S. scardica. The predominant components were trans-caryophyllene, ß-pinene, α-pinene and 1-octen-3-ol, which were found only in the fresh samples. In the aerial parts of S. rteseri, 43 components were identified in the dried samples {22 monoterpenes (65.7-94.3%) and 21 sesquiterpenes (5.4- 27.8%)} and 29 components {15 monoterpenes (77.3-90.7%) and 14 sesquiterpenes (6.3- 18.2%)} in the respective fresh samples. Prevailing components in all tested samples of S. raeseri were ß-pinene, α-pinene, α-copaene, sabinene and limonene. Only minor differences were revealed in the qualitative composition of the aroma volatiles between the dried and fresh plant material of both species. Furthermore there was almost no difference in the chemical profiles of the aroma compounds between S. scardica and S. raeseri, except for 1- octen-3-ol, which was present only in fresh S. scardica.

Phytochemistry and chemotaxonomy of Sideritis species from the Mediterranean region.

The phytochemical content of the Mediterranean species of the Sideritis genus has been reviewed. The components included in this review are monoterpenes, sesquiterpenes, diterpenes, triterpenes, sterols, flavones, coumarins and phenylpropanoids. From the chemotaxonomic point of view, we have divided the species from this region into four groups. The first of this is formed by taxa containing triterpenes, but not diterpenes. A second group is constituted by species having bicyclic diterpenes of the labdane type and not diterpenes. The third group is characterized by its content in tetracyclic diterpenes of the ent-kaurene type. A fourth group is composed of plants with tetracyclic diterpenes of the ent-beyer-15-ene and/or ent-atis-13-ene class. In addition, the relations of these Mediterranean species with those of the Macaronesian region have been examined.

A chemotaxonomic study of nine Canarian Sideritis species.

Nine taxa of the Sideritis genus, Sideritis argosphacelus var. spicata, Sideritis candicans var. eriocephala,Sideritis discolor, Sideritis kuegleriana, Sideritis lotsyi, Sideritis lotsyi var. mascaensis, Sideritis marmorea, Sideritis soluta and Sideritis tenoi, which are endemic from the Canary Islands, have been chemically studied. The diterpene sicanatriol 7beta,18-diacetate was obtained from S. argosphacelus var. spicata, whilst a nor-diterpene, epiadejone, and the 3(2H)-benzofuranone solutin have been found in S. soluta. Another diterpene, sidendrodiol 18-monoacetate, has been isolated from S. argosphacelus var. spicata, for the first time as a natural product. Known sesquiterpenes, diterpenes, triterpenes, sterols, flavones, coumarins and other aromatic derivatives have also been isolated. These studies support the botanical division of the genus into two subgenera, Sideritis and Marrubiastrum, the three sections of the latter subgenus, Cretica, Empedocleopsis and Marrubiastrum, and the elevation of S. argosphacelus var. spicata, S. candicans var. eriocephala and S. lotsyi var. mascaensis to the rank of species.