Bioassay-Guided Skin-Beneficial Effects of Fractionated Sideritis raeseri subsp. raeseri Extract

Abstract

This study aimed to evaluate the potentials for skin-beneficial effects of the hydroethanolic extract of the aerial parts of ironwort (Sideritis raeseri Boiss. & Heldr. subsp. raeseri) and its fractions (petroleum ether, ethyl acetate, n-butanol and water). For these purposes, chemical analysis and in vitro antioxidant, anti-tyrosinase and antimicrobial assays, as well as determination of sun protection factor (SPF), were performed. The highest total phenolic content and quantity of individual flavonoids, chlorogenic acid and verbascoside were determined in the n-butanol fraction, which is in line with results obtained for antioxidant activity. The greatest antimicrobial activity against Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa, the most common causative agents of the skin infections in humans, was exhibited by the ethyl acetate fraction. The strongest anti-tyrosinase activity was shown by the hydroethanolic extract (52.64% of inhibition at 100 μg/mL). Almost all tested samples showed photoprotective activity with SPF higher than 6 obtained at a low concentration of 0.1 mg/mL, which was more than 15 for the butanol fraction. These findings revealed that the hydroethanolic extract of S. raeseri aerial parts could be a valuable ingredient in the formulation of cosmetic and medicinal products intended to overcome various skin disorders.

Spasmolytic Activity of Gentiana lutea L. Root Extracts on the Rat Ileum: Underlying Mechanisms of Action

“…A similar distribution pattern of flavonoids of Sideritis raeseri subsp. raeseri hydroethanolic extract was reported by Krgović et al [26], where the n-butanol fraction showed the highest concentration of hypolaetin and isoscutellarein derivatives. Overall, no single fraction is optimal for separating all individual compounds simultaneously, but the choice depends on specific target compounds of interest.…”

Comparative Study on Assisted Solvent Extraction Techniques for the Extraction of Biologically Active Compounds from Sideritis raeseri and Sideritis scardica

“…The optimal ethanol concentration for the high-rate extraction of total phenols from S. raeseri was established as 70% in a previous study [ 1 ]. Moreover, when targeting phenolic compounds from S. raeseri , it was proven that aqueous ethanolic extract could be further enriched by successive extraction with ethyl acetate [ 2 ]. In previous research reports, total phenolic content was significantly higher in S. raeseri , whereas total flavonoid content was higher in S. scardica [ 18 ].…”

“…These compounds also contributed to the antioxidant activity of S. raeseri , but not as strongly as compounds 80 (4′- O -methylisoscutellarein 7- O -[6‴- O -acetyl]-allosyl(1→2)glucoside) and 52 (verbascoside) ( Figure 1 A). According to Krgović et al [ 2 ], the antioxidant activity of S. raeseri was the most positively correlated with the content of 4′- O -methyl-isoscutellarein 7- O -[6‴- O -acetyl- β -D-allopyranosyl-(1→2)]- β -D-glucopyranoside and 4′- O -methyl-hypolaetin 7- O -[6‴- O -acetyl- β -D-allopyranosyl(1→2)]-6‴- O -acetyl- β -D-glucopyranoside, identified also in our study as compounds 80 and 83 , respectively. However, in our study, the antioxidant activity of compound 83 was not observed at all in S. raeseri extracts, whereas in S. scardica extracts, it was relatively weak compared to other antioxidants.…”

“…The Mediterranean region, the Balkan Peninsula and the Middle East possess suitable climate conditions for house plant communities rich in herbs and shrubs from the Lamiaceae family, including the Sideritis genus [ 1 ]. In traditional medicine, infusions or decoctions prepared with the flowering aerial parts of the Sideritis species were widely used for the treatment of the common cold, cough, gastrointestinal disorders and for the healing of wounds [ 2 , 3 ]. Sideritis scardica , endemic to the Balkan Peninsula [ 4 ], is known also as ironwort.…”

“…Another research goal was to determine whether and to what extent the use of assisted extraction with microwaves, ultrasounds or high pressure would affect the extraction efficiency and profile of phytochemicals. Former studies on extraction methods used for the isolation of Sideritis metabolites usually were limited to determinations of the total flavonoid content, the total phenolic content, the total antioxidant activity of extracts and selected individual compounds [ 1 , 2 , 19 , 20 , 21 , 22 ]. In this study, consideration has been extended to the assessment of the impact of the extraction method on the detailed phytochemical composition in S. raeseri and S. scardica extracts.…”