Secondary metabolites, phytochemical characterization and antioxidant activities of different extracts of Sideritis congesta P.H. Davis et Hub.-Mor.
Introduction
As reported by the up to date taxonomical classification, Sideritis genus (Lamiaceae) includes over 150 species spread in the Western Palearctic zone. The name Sideritis evolved from the Greek "σίδερο", which means iron, as it is used for curing wounds caused by metal arms (Aneva et al., 2019). In Turkey, this genus contains 46 species with high rates of endemism (36 of which are endemic). The plant is known as “dağ çayı" (mountain tea) in Turkey. In addition to its utilization as stimulating tea or flavoring agent, infusion has been consumed for healing purposes. Sideritis spp. is utilized against cough, gastrointestinal complaints, and other symptoms of common cold as well as wound healing in traditional medicine (Baytop, 1999). Furthermore, researches proposed that the members of Sideritis genus have a broad range of pharmacological activities such as antimicrobial, antiproliferative, antiinflammatory, antifungal, antiulcerogenic, as well as antidiabetic (Gonzalez-Burgos et al., 2011). Amongst Sideritis spp., Sideritis congesta P.H. Davis et Hub. Mor. is an endemic plant to Southern Anatolia, Turkey. Ethnobotanical studies revealed that S. congesta is used against high blood pressure, cough, and obesity in Turkey (Aneva et al., 2019). Although, there are numerous studies regarding the secondary metabolites of Sideritis spp., only few are related with S. congesta which were particularly concentrated on the essential oil composition and terpenoids. Ent-kaurane diterpenoids were previously reported from the petroleum ether, acetone, and ethyl acetate extracts of the whole plant of S. congesta (Oktemer and Logoglu, 2003; Topcu et al., 2011). Three flavonoids known as chrysoeriol 7-O-gentiobioside, chrysoeriol 7-O-β-D-glucoside and salvigenin were isolated from EtOAc and petroleum ether extracts of S. congesta, respectively by Sezik and Ezer (1984). Furthermore, HPLC-DAD analysis for some free flavonoids and cinnamic acid derivatives of above ground parts of S. congesta showed existence of the high amounts of p-coumaric acid, chlorogenic acid, ferulic acid along with apigenin (Erkan et al., 2011). The essential oil distilled from S. congesta was dominated by β-pinene and α-pinenes (Ezer et al., 1996; Ozcan et al., 2001; Krimer et al., 2001; Ozel et al., 2008; Gumuscu et al., 2011). S. congesta has also been studied for its antioxidant, acetylcholinesterase inhibitory and analgesic activities by Aydin and Ozturk (1996), Erdogan-Orhan et al. (2010), Topcu et al. (2011), and Erkan et al. (2011).
Despite its widely use in Turkish folkloric medicine, S. congesta has not been investigated in terms of its major secondary metabolites through both isolation and analytical (HPTLC and LC-MS/MS) studies. Furthermore, the antioxidant potential of its crude MeOH extract and fractions were not previously investigated comparatively. Accordingly, this study was designed to comparatively assess the antioxidant potentials of crude MeOH extract, fractions (CHCl3, EtOAc, Remaining-H2O) and infusion prepared from the aerial parts of S. congesta by using several in vitro methods as well as to characterize their phenolic compositions by LC–MS/MS and HPTLC techniques. Additionally, main secondary metabolites of the R-H2O fraction were isolated, and their structures were elucidated by NMR and MS experiments.
Section snippets
General procedures
Chromatography: Column chromatography (CC) was achieved on silica gel 60 (0.063–0.200 mm; Merck, Darmstadt, Germany), Sephadex LH-20 (25–100 μm; Sigma-Aldrich, St. Louis, MO, USA) and Polyamide (50–160 μm; Fluka Analytical, Sigma-Aldrich, St. Louis, MO, USA). Medium-pressure liquid chromatography (MPLC) was completed using Sepacore® Flash Systems X10/X50 (Buchi Labortechnik AG, Flawil, Switzerland) on Redisep columns LiChroprep C18 and SiO2 (Teledyne Isco, Lincoln, Nebraska, USA). Thin layer
Isolation and structure elucidation of isolates
The R-H2O fraction was selected to purify the secondary metabolites based on the preliminary TLC analysis of the main fractions which revealed the existence of some different secondary metabolites in R-H2O fraction together with the phenolics that are also present in EtOAc fraction as well as the high amount of aqueous fraction. The successive chromatographic separations on the aqueous fraction afforded seven metabolites belonging to the subclasses of phenylethanoid glycoside [verbascoside (1
Conclusion
In this study the in vitro antioxidant potential of S. congesta as well as its secondary metabolite composition was investigated. The EtOAc and R-H2O fractions exhibited significant antioxidant potential. Phytochemical studies on the polar fraction (R-H2O) yielded seven secondary metabolites three of which (2, 6 and 7) are new for the genus Sideritis. Overall, these findings provided scientific basis for the traditional use of S. congesta which was shown to be potent antioxidant agent and rich
CRediT authorship contribution statement
Hilal Bardakci: Conceptualization, Formal analysis, Writing - original draft. Dicle Cevik: Conceptualization, Formal analysis, Writing - original draft. Timur Hakan Barak: Formal analysis, Writing - original draft. Tuba Gozet: Formal analysis, Writing - original draft. Yuksel Kan: Resources, Supervision. Hasan Kirmizibekmez: Supervision, Conceptualization, Writing - original draft.
Declaration of competing interest
Authors declare there are no conflicts of interest to report.
References (42)
- et al.
Structures of verbascoside and orobanchoside, caffeic acid sugar esters from Orobanche rapum-genistae
Phytochemistry
(1982) - et al.
The ferric reducing ability of plasma (FRAP) as a measure of antioxidant power: the FRAP assay
Anal. Biochem.
(1996) - et al.
Phenylpropanoid glycosides from Marribium alysson
Phytochemistry (Oxf.)
(1992) - et al.
Glycosides from Phlomis lunariifolia
Phythochem
(2004) - et al.
A comparative study on the in vitro antioxidant potentials of three edible fruits Cornelian cherry, Japanese persimmon and cherry laurel
Food Chem. Toxicol.
(2012) - et al.
The bioaccessible phenolic profile and antioxidant potential of Hypericum perfoliatum L. after simulated human digestion
Ind. Crop. Prod.
(2017) - et al.
Influence of extraction method on enzyme inhibition, phenolic profile and antioxidant capacity of Sideritis trojana
Bornm. S. Afr. J. Bot.
(2019) - et al.
Antioxidant activities of Sideritis congesta Davis et Huber Morath and Sideritis arguta Boiss et Heldr: identification of free flavonoids and cinnamic acid derivatives
Food Res. Int.
(2011) - et al.
Essential oil composition of four Turkish species of Sideritis
Phytochemistry
(1996) - et al.
Sideritis spp.: uses, chemical composition and pharmacological activities-a review
J. Ethnopharmacol.
(2011)
Evaluation of the phytochemical content, antioxidant activity and antimicrobial properties of mountain tea (Sideritis syriaca) decoction
J. Func. Foods
Chemical profile, antioxidant activity and stability in stimulated gastrointestinal tract model system of three Verbascum species
Ind. Crop. Prod.
Chlorogenic acid (CGA): a pharmacological review and call for further research
Biomed. Pharmacother.
Essential oil composition of Turkish mountain tea (Sideritis spp.)
Food Chem.
Flavonoids as chemotaxonomic markers in the polymorphic Stachys swainsonii (Lamiaceae)
Biochem. Systemat. Ecol.
Ent-kaurane diterpenoids isolated from Sideritis congesta
Phytochem. Lett.
Chemical fingerprints, antioxidant, enzyme inhibitory, and cell assays of three extracts obtained from Sideritis ozturkii Aytaç & Aksoy: an endemic plant from Turkey
J. Pharmaceut. Biomed. Anal.
Activity guided fractionation of Arum italicum Miller tubers and the LC/MS-MS Profiles
Record Nat. Prod.
Iridoid glucosides from sideritis lycia Boiss. & Heldr. And its antimicrobial activities
FABAD Farmasötik Bilimler Dergisi
Genus Sideritis, section Empedoclia in southeastern Europe and Turkey–studies in ethnopharmacology and recent progress of biological activities
Daru
Novel total antioxidant capacity index for dietary polyphenols and vitamins C and E, using their cupric ion reducing capability in the presence of neocuproine: CUPRAC method
J. Agric. Food Chem.
Cited by (16)
HPTLC quantification, assessment of antioxidant potential and in vivo hypoglycemic activity of Scorzonera latifolia (Fisch. & Mey.) DC and its major compounds
2022, South African Journal of BotanyCitation Excerpt :Butylated hydroxytoluene was selected as the reference compound. The CUPRAC of the extract was determined by the assay adapted before (Bardakci et al., 2020). Copper (II) sulfate and neocuproine was added in the ammonium acetate buffer in equal volume.
Exploring the multifaceted effects of Ammi visnaga: subchronic toxicity, antioxidant capacity, immunomodulatory, and anti-inflammatory activities
2024, Journal of Toxicology and Environmental Health - Part A: Current IssuesCholinergic cognitive enhancer effect of Salvia triloba L. essential oil inhalation in rats
2023, Marmara Medical JournalChemical profile of the Anatolian Sideritis species with bioactivity studies
2023, Pharmaceutical Biology