Şimşek, Samed

Satureja hortensis, widely used in traditional medicine and culinary applications, is a valuable aromatic plant rich in essential oils (Eos) and bioactive compounds. This study comprehensively evaluated the phytochemical composition and biological properties of S. hortensis grown in Erzincan, Turkey. The EO and four solvent-based extracts (ethyl acetate, butanol, water extract (WE), and water fraction) were analyzed. GC–MS/MS identified 34 volatile compounds (98.76%), with thymol (40.83%), carvacrol (19.77%), γ-terpinene (16.71%), and p-cymene (12.06%) as major constituents. LC-ESI-MS/MS revealed phenolic compounds, with hesperidin, rutin, and caffeic acid as major constituents in ethyl acetate and butanol fractions. Antioxidant activity was determined by DPPH, ferric reducing antioxidant power (FRAP), TPC, and TFC assays. The ethyl acetate showed the strongest DPPH scavenging (17.25 ± 2.34 μg/mL), highest TPC (79.24 ± 0.59 mg gallic acid equivalent /g), and moderate FRAP activity (96.86 ± 1.06 mg TE/g), while the WE had the highest flavonoid content (48.21 ± 1.56 mg QE/g). The EO exhibited potent antimicrobial activity (MIC 31.25–250 μg/mL; maximum inhibition zones 50 mm) against A. niger, C. albicans, and A. alternata. HPLC-DAD quantified rosmarinic acid, highest in ethyl acetate extract (580.93 ± 1.12 mg/g). Pearson correlation analyses demonstrated strong positive associations between phenolic content and biological activities, supporting the pharmaceutical, cosmetic, and industrial potential of S. hortensis.

Şimşek, Samed; Akşit, Hüseyin; Köksal, Ekrem; Altay, Ahmet

This study, for the first time, investigated the antioxidant, antidiabetic, and antiproliferative properties of methanolic extracts from the aerial and root parts of four endemic Verbascum species—Verbascum leiocarpum Murb., Verbascum ozturkii Karavel., Uzunh. & S.Çelik, Verbascum alyssifolium Boiss., and Verbascum tuna-ekimii Karavel., A.Duran & Hamzaoğlu—and quantitatively determined their verbascoside content using HPLC-DAD. Antioxidant capacity was evaluated by DPPH and FRAP assays, and total phenolic content (TPC) and total flavonoid content (TFC) were also determined. Antidiabetic activity was assessed through α-glucosidase inhibition, and antiproliferative effects were determined in A549, MDA-MB-453, and HT-29 human cancer cell lines. Among the tested samples, the root of V. leiocarpum exhibited the highest TPC (50.89 mg GAE/g extract), FRAP value (124.16 mg TE/g extract), DPPH scavenging ability (IC50: 58.82 μg/mL), and verbascoside content (129.06 mg verbascoside/g extract). This extract also exhibited significant antiproliferative effects against A549 and MDA-MB-453 cells, with inhibition rates of 85% and 69%, respectively. In contrast, both aerial and root extracts of V. tuna-ekimii exhibited low biological activity and a lower concentration of verbascoside. Pearson correlation analysis demonstrated strong positive associations between verbascoside content and both antioxidant and antiproliferative parameters. However, no significant correlation was found between verbascoside content and α-glucosidase inhibition, suggesting that other phytochemicals may be responsible for the antidiabetic activity. These findings indicate that V. leiocarpum, especially its root extract, may be considered a valuable source of natural antioxidants and antiproliferative agents. The study highlights the pharmacological potential of endemic Verbascum species that have not been comprehensively investigated phytochemically or pharmacologically and supports their further evaluation in the context of phytopharmaceutical research.

Şimşek, Samed; Varol, Tuğçe; Altın, Sevgi; Yılmaz, Mustafa Abdullah; Aydın, Ali; Elveren, Müjgan; Alp, Cemalettin; Köksal, Ekrem; Osma, Etem

Hedysarum candidissimum (HC), a species endemic to Türkiye, represents a potential source of bioactive phytochemicals with pharmacological applications. This study provides the first comprehensive investigation of the species, integrating organ-specific phytochemical profiling with biological activity evaluations. Methanolic extracts from leaf, stem, and root were analyzed for their phytochemical composition and biological activities. Liquid Chromatography–Tandem Mass Spectrometry analysis quantified 53 phenolic compounds and revealed organ-dependent differences in metabolite distribution. Quinic acid was the major phenolic acid, with the highest content in the stem (91.81 mg/g extract), while flavonoid glycosides such as isoquercitrin (90.72 mg/g extract) and astragalin (43.61 mg/g extract) were higher in leaves. Antioxidant activity was determined by DPPH, FRAP, TPC, and TFC assays. The leaf extract showed the strongest activity, with the lowest DPPH IC50 (5.43 ± 0.18 µg/mL), highest reducing power (192.47 ± 0.91 mg TE/g extract), and highest phenolic and flavonoid contents (220.84 ± 1.07 mg GAE/g extract and 107.26 ± 0.77 mg QE/g extract). Enzyme inhibition assays demonstrated strong activity against acetylcholinesterase, butyrylcholinesterase, and α-glucosidase (2.44 ± 0.11, 3.35 ± 0.37, and 3.40 ± 0.20 µg/mL). Antiproliferative activity showed moderate growth inhibition in lung (A549, Calu1, H1650) and breast (MCF-7, MDA-MB-231) cancer cell lines (GI50: 2.40–19.15 µg/mL), with higher sensitivity in breast cells. The stem extract exhibited the highest tumor selectivity index (1.83), while LDH assays indicated low toxicity. Multivariate analyses confirmed organ-specific metabolite patterns and relationships between phenolic composition and biological activities. These findings indicate that the species, particularly the leaf extract, represents a source of phenolic metabolites for further phytochemical and biological investigation.

Elveren, Müjgan; Varol, Tuğçe; Şimşek, Samed; Aydın, Ali; Yılmaz, Mustafa Abdullah; Altın, Sevgi; Osma, Etem

Hedysarum erythroleucum is a plant species native to Türkiye and represents a potential source of bioactive compounds. This study investigated the phytochemical composition and biological activities of methanolic extracts prepared from the leaves, stems, and roots. LC-MS/MS analysis identified 53 phenolic compounds and revealed clear differences in metabolite distribution among plant organs. Quinic acid was the predominant phenolic acid, particularly in the leaf extract. Flavonoid glycosides such as isoquercitrin, astragalin, and rutin were also abundant in the aerial parts of the plant. The antioxidant potential of the extracts was evaluated using DPPH, FRAP, total phenolic content, and total flavonoid content assays. Among the tested plant parts, the leaf extract exhibited the strongest antioxidant activity, with the lowest DPPH IC50 value, the highest reducing power, and the highest total phenolic and flavonoid contents. These findings indicate that the leaves contain high levels of antioxidant compounds. Enzyme inhibition assays showed that the leaf extract exhibited the highest inhibitory activity against acetylcholinesterase, butyrylcholinesterase, and α-glycosidase. Its activity was comparable to that of the reference inhibitors under the experimental conditions. Antiproliferative activity was assessed against lung and breast cancer cell lines. All extracts inhibited cancer cell growth, with the highest sensitivity observed in H1650 and MDA-MB-231 cells. Tumor selectivity indices suggested moderate selectivity, especially for root extracts. LDH cytotoxicity analysis indicated limited membrane damage, suggesting that the extracts primarily exert cytostatic effects by suppressing cell proliferation rather than inducing extensive cell death. Multivariate analyses revealed organ-specific metabolite patterns and associations between phenolic composition and the measured biological activities. Overall, the findings indicate that H. erythroleucum, particularly the leaf extract, contains a high content of phenolic compounds and exhibits promising in vitro antioxidant, enzyme inhibitory, and antiproliferative activities. These findings provide a basis for future phytochemical investigations, mechanistic studies, compound isolation, and in vivo validation.

Şimşek, Samed; Varol, Tuğçe; Akşit, Zeynep; Elveren, Müjgan; Osma, Etem

In this study, the flowers of 20 plant species [Gypsum (Linum flavum, Paracaryum stenolophum, Onobrychis nitida, Gypsophila lepidioides, Psephellus recepii, Tanacetum heterotomum, Verbascum alyssifolium, limestone (Teucrium leucophyllum, Stachys sparsipilosa, Phlomis oppositiflora, Pelargonium endlicherianum, Chrysophthalmum montanum, serpentine (Convolvulus pseudoscammania, Fumana aciphylla, Gladiolus halophilus, Hypericum thymbrifolium, Salvia indica, Artedia squamata, Erysimum pulchellum, Consolida olopetala], including 11 endemic species, growing in various habitats (gypsum, limestone, and serpentine) in Erzincan province were examined. By focusing on the antioxidant capacities and antibacterial activities of these species, the study aims to elucidate the effects of these ecosystems on the biosynthesis of plant secondary metabolites, primarily phenolic compounds and flavonoids, and their adaptive biochemical responses to unique environmental conditions. Antioxidant properties were assessed using DPPH, FRAP, TPC, and TFC assays. Results showed significant differences in antioxidant compound concentrations among plants from different habitats, with the highest levels in serpentine and gypsum regions. Artedia squamata L. from serpentine had the strongest DPPH activity (24.83 ± 1.25 µg/ml), Erysimum pulchellum had the highest TPC (89.44 ± 0.76 mg GAE/g), and Tanacetum heterotomum had the highest TFC (43.48 ± 2.08 mg QE/g) in gypsum. FRAP activity was highest in serpentine species, particularly Consolida olopetala (32.14 ± 1.84 mg TE/g). Furthermore, Antibacterial assays against eight ATTC strains revealed significant inhibitory effects by Stachys sparsipilosa, Tanacetum heterotomum, Teucrium leucophyllum, and Verbascum alyssifolium against Enterococcus faecium and Salmonella enteritidis with Teucrium leucophyllum showing the highest activity (MIC of 31.25 µg/ml against Salmonella enteritidis). The study highlights the influence of habitat on the biosynthesis of bioactive compounds, suggesting that plants from serpentine and gypsum soils have enhanced antioxidant and antimicrobial properties, making them potential candidates for natural therapeutic agents.