Onosma Species Research Articles

Onosma vanensis (Boraginaceae: Lithospermeae); A New Species from Van, Türkiye

A new species of Onosma (Boraginaceae: Lithospermeae) from the Van province of eastern Anatolia, Onosma vanensis Fırat & Binzet, is described and illustrated. It belongs to Haplotricha informal group which comprises the species with basal leaves covered by simple setae only. In general appearence, it’s close to O. lanceolata Boiss. & Hausskn. but it’s a different species with narrow stem leaves, larger bracts, shorter pedicels and calyx as well as longer corolla. The geographical distribution of O. vanensis and O. lanceolata are mapped and the identification key for those species is provided. Additionaly, diagnostic characters, detailed photographs and habitat descriptions provided along with a vernacular name and IUCN conservation status for O. vanensis.

A new species of Onosma (Boraginaceae) from Bakhtiari Mountains in Iran

A new species, Onosma bakhtiarica (Boraginaceae), has been discovered in Iran’s Chaharmahal and Bakhtiari province. The plant is found in the Tang-e Beheshtabad and belongs to sect. Onosma subsect. Haplotricha. Morphologically, it is closely related to O. pachypoda and O. sericea. Still, it differs from the mentioned species by the rosette leaf shape, shape of rosette leaf apex, shorter cauline leaf, cauline leaf width and shape, arrangement of setae, corolla color and shape, shorter pedicel length in flowering and fruiting, shorter fruiting calyx, bract shape, nutlet shape and size, nutlet ornamentation, and a hairy annulus. In addition, O. bakhtiarica is distinguished from O. pachypoda by its light brown nutlet, rosette leaf with a long petiole, and cauline leaf with an acute apex. It can also be distinguished from O. sericea by the dense short hairs covering the corolla’s exterior. Diagnostic characters, a comprehensive description, photographs, and a distribution map are provided. An identification key for haplotrichous Onosma species of Iran is also provided.

Bioassay-guided isolation and in silico study of antihyperlipidemic compounds from Onosma hispidum Wall

Isolation of bioactive compounds from plants and their therapeutic evaluation is crucial in the pursuit of novel phytochemicals and contributes an indispensable role in drug discovery and design. The literature has documented the hypolipidemic effect of numerous Onosma species. Taking that into consideration, the current study was designed to isolate, purify and evaluate the antihyperlipidemic potential of leaves of Onosma hispidum Wall. For the first time, the bioassay-guided isolation led to the separation of 3 compounds that were identified by spectroscopic techniques as o-phthalic acid bis-(2-ethyl decyl)-ester (1), bis (2-ethyloctyl) phthalate (2), and 1,2 benzenedicarboxylic acid bis(2-methyl heptyl) ester (3). Lipase inhibition assay was utilized to scrutinize the antihyperlipidemic potential of methanolic extract fractions and subsequently isolated compounds. Further, the isolated compounds were employed for in silico studies via molecular docking, molecular mechanics with generalized born and surface area solvation (MM-GBSA), and MD simulations with Pancreatic Lipase Colipase (PDB ID: 1LPB). Molecular docking and MM-GBSA of isolated compounds were employed to explain the mode of binding between the protein–ligand complex and binding free energy calculation, respectively. Since compound (3) displayed the best docking score of −6.689 kcal/mol as compared to orlistat −5.529 kcal/mol with PDB: 1LPB. So, it was chosen for MD simulations to evaluate ligand stability and flexibility of the complex which was validated by the fluctuation of α-carbon chain, root mean square deviation (RMSD), root mean square fluctuation (RMSF), and type of interactions involved which authenticated the in vitro lipase inhibitory potential. Overall, in silico and in vitro results validated that compound (3) could be exploited as a promising pancreatic lipase inhibitor. Communicated by Ramaswamy H. Sarma

Supermatrix analyses reveal the importance of outgroup, gene and taxon sampling in Onosma (Boraginaceae) phylogenetics

Tribe Lithospermeae (Boraginaceae) consists of ca. 26 genera and 470 species, in which Onosma constitutes approximately one third of the species (~150). Although the tribe is strongly supported as monophyletic, both generic and species boundaries remain ambiguous. Among them, not only the phylogenetic position of Eastern Asian Onosma species, but also the taxonomic limits of the genus remain unclear. Whether Eastern Asian Onosma is monophyletic, or the genus should be widened to include Maharanga, and maybe Cystostemon, are still open questions. For these reasons, I performed 16 phylogenetic analyses with different taxon coverages, alignments, gene regions and outgroups, with up to 746 taxa of tribe Lithospermeae and with five DNA regions, using data from GenBank. The results, with the widest taxon coverage to date, show that while genus Onosma is not monophyletic in any of the analyses, the phylogenetic relationships among Onosma s.s., Eastern Asian Onosma, Maharanga and Cystostemon differ among analyses. However, the approximately unbiased (AU) test showed that the topology (((Eastern Asian Onosma+Maharanga) Cystostemon) Onosma s.s.) is overwhelmingly supported. Therefore, the current study highlights the importance of taxon, gene and outgroup sampling in Onosma phylogenetics.

Chemopreventive Effects of Onosma mutabilis against Azoxymethane-Induced Colon Cancer in Rats via Amendment of Bax/Bcl-2 and NF-κB Signaling Pathways.

Onosma species (Boraginaceae) are well known as medicinal plants due to their wide range of pharmaceutical potential. The present study aims to investigate the anticancer (in vitro) and chemo-protective (in vivo) efficacies of Onosma mutabilis extract (OME) in the azoxymethane (AOM)-induced aberrant crypt foci (ACF) in rats. The in vitro antiproliferative effects of OME were determined on two human tumor cell lines (Caco-2 and HT-29) via MTT assay. The in vivo chemoprotective effects of OME were investigated by performing various biochemical analyses in serum and tissue homogenates of albino rats, along with determining oxidative stress biomarkers. Inflammatory biomarkers of colon, colonic gross morphology (by methylene blue), ACF formation, and colonic histopathology (H & E stain) were determined. The immunohistochemistry of colonic tissues was also assessed by Bax and Bcl-2 protein expression. The results showed that the antitumor activity of OME against Caco-2 and HT-29 colorectal cancer cells ranged between 22.28-36.55 µg/mL. OME supplementation caused a significant drop in the ACF values and improved the immunohistochemistry of the rats shown by up-regulation of Bax and down-regulation of Bcl-2 protein expressions. These outcomes reveal that O. mutabilis may have chemoprotective efficiency against AOM-induced colon cancer represented by the attenuation of ACF formation possibly through inhibition of free radicals, inflammation, and stimulation of the colon antioxidant armory (SOD, CAT, and GPx) and positive regulation of the Nrf2-Keap1 pathway.

Seed Lipids of Onosma Species from Various Climate Zones

Seed Lipids of Onosma Species from Various Climate Zones

Ethnobotanical, Phytochemistry, and Pharmacological Activity of Onosma (Boraginaceae): An Updated Review.

The genus Onosma belongs to the Boraginaceae family and contains over 230 species. The present review sheds light on the ethnopharmacology, phytoconstituents, bioactivity, and toxicology of the Onosma species from previous investigations. Furthermore, the paper also highlights the unresolved issues for the future investigations. The review included previous studies of the genus Onosma available from Google Scholar and Baidu Scholar, Science Direct, SciFinder, Wiley Online Library, and Web of Science. Until now, more than 200 chemical compounds have been detected from the genus Onosma, including naphthoquinone (33), flavonoids (30), hydrocarbon (23), phenolic (22), ester (17), alkaloids (20), aromatics (12), carboxylic acid (11), fatty acids (9), terpenoids (10), while the most important ones are rosmarinic, ferulic, protocatechuic, chlorogenic, caffeic, p-coumaric acids, and apigenin. The Onosma species are reported as traditional medicine for wound healing, heart disease, and kidney disorders, while the pharmacological investigations revealed that the extracts and the phytochemicals of Onosma species have different therapeutic properties including antioxidant, enzyme inhibitory, antitumor, hepatoprotective, antiviral, anti-inflammatory, and antimicrobial actions. The summarized knowledge in this review provides valuable ideas for the current and future drug discovery and a motivation for further investigation on the genus Onosma.

Diversity centers as well as conservation priorities of the genus Onosma L. (Boraginaceae) in Iran

Conservation of biological diversity is one of the most important issues in conservation biology, so a wide range of quantitative spatial methods have been used to determine the biodiversity hotspots and the conservation priority areas. The main aims of the present study are determining the areas of endemism as well as the centers of diversity of the genus Onosma based on the GIE, IPAs, species richness, and AZE-like criteria approaches, to assess the status and priorities of conservation of the mentioned genus in Iran. Based on the findings of this research, centers of species richness, the main areas of endemism, top-ranked IPAs, and AZE-like criteria are situated in the Zagros ecosystems. The comparison of the four approaches used in this study shows that the IPAs and GIE techniques have succeeded in identifying the most important centers of diversity and endemism of Onosma in Iran. Considering that this genus with a high percentage of endemic species is one of the most important genera of Iranian flora and only 46 % of the IPAs and areas of endemism specified in the research are located in protected areas, identification and protection of the rest of these areas is one of the prevalent measures needed for conservation of Onosma species diversity in Iran.

Antiproliferative and cytotoxic effects of bioactive compounds isolated from Onosma bourgaei.

Onosma species have been used commonly for traditional medicine for years due to their bioactive compounds content. Onosma bourgaei aerial part was extracted with hexane and methanol successively. The methanol extract was subjected to chromatographic techniques to isolate allantoin (1), 3,4-dihydroxybenzaldehyde (2), luteolin-7-O-glucoside (3), apigenin-7-O-β-glucoside (4), diosmetin-7-O-β-glucoside (5), rosmarinic acid (6), and globoidnan A (7). The structure of isolated compounds were identified by spectroscopic techniques such as 1D-NMR, 2D-NMR, FTIR, and LC-TOF/MS/MS. Antiproliferative activity of extract and natural compounds were carried out using HeLa (human epithelial cervix adenocarcinoma, ATCC® CCL-2™), HT29 (human colorectal adenocarcinoma, ATCC® HTB38™), MCF7 (human mammary gland adenocarcinoma, ATCC® HTB22™), and A549 (human lung carcinoma, ATCC® CCL185™) cancerous cells and normal cells, FL (human epithelial amnion cell, ATCC® CCL62™). Lactate dehydrogenase (LDH) was performed for cytotoxicity. The compounds, 4, 6, and 7 displayed the strong antiproliferative activity against corresponding cell lines. Apigenin-7-O-β-glucoside (4) revealed the excellent activity on HeLa, HT29, A549, and MCF6 cancer cell lines with the values of (IC50, µM) 167.3, 196.8 181.1, and 203.5, respectively, compared standard compound, cisplatin.

Phytochemical Analysis and Biological Evaluation of Two Endemic Onosma Species (Onosma cappadocica and O. rutilum)

Onosma species have been used by the public for centuries to treat various diseases. This study aimed to analyze the chemical composition, antioxidant, and enzyme inhibitory activity potentials of the methanol extracts of O. cappadocica and O. rutilum, endemic to Turkish flora. The chemical compositions of the extracts were determined by using spectrophotometric and chromatographic methods. The biological activities of the extracts were determined by using antioxidant and enzyme inhibitory test systems. It was determined that the extracts contain high amounts of hesperidin, hyperoside, and rosmarinic acid. While O. rutilum exhibited higher activity in phosphomolybdenum, ABTS radical scavenging and ferrous ion chelating assays, reducing power, and DPPH radical scavenging tests resulted in the superiority of O. cappadocica. O. rutilum exhibited higher inhibition activity on all enzymes (acetylcholinesterase, butyrylcholinesterase, tyrosinase, and -amylase), except for -glucosidase. It was concluded that the extracts in question could be used as alternative agents in the food, cosmetic and medical industries due to their antioxidant and enzyme inhibitory activities.

Two Onosma Species (Onosma microcarpum and O. nana) as an Alternative Source of Multifunctional Agents: Biological and Phytochemical Evaluation

Phytochemicals have significant biological effects. This study aimed to investigate the chemical composition, antioxidant and inhibitory activities of methanol (MeOH) extracts obtained from the aerial parts of Onosma microcarpum DC. and O. nana DC. on enzymes that play a critical role in digestive and cholinergic systems and melanogenesis process. The chemical compositions of the extracts were determined by using spectrophotometric and chromatographic methods. The biological activities of the extracts were determined by using antioxidant and enzyme inhibitory test systems. According to spectrophotometric analysis, both phenolic and flavonoid concentrations of O. nana were found higher than O. microcarpum (44.63 mg GAEs/g and 27.86 mg QEs/g, respectively). Chromatographic analysis shows that O. nana contains a high amount of hesperidin (53412.37 µg/g). In comparison, O. microcarpum has rosmarinic acid (13181.91 µg/g), apigenin 7-glucoside (11693.97 µg/g), luteolin 7 -glucoside (8632.03 µg/g) and pinoresinol (1014.26 µg/g) as the main compounds. In the ferrous ion chelating activity test, extracts exhibited almost similar activities. In contrast, radical scavenging (DPPH and ABTS), reducing power (CUPRAC and FRAP), and phosphomolybdenum tests resulted in the superiority of O. nana (229.98, 243.58, 327.46, 189.69, and 783.14, mg TEs/g, respectively). In the α-amylase inhibitory activity test, O. microcarpum showed higher activity (406.31 mg ACEs/g). In comparison, α-glucosidase (958.23 mg ACEs/g) and acetylcholinesterase (AChE) (2.80 mg GALAEs/g), butyrylcholinesterase (BChE) (2.59 mg GALAEs/g), and tyrosinase (200.43 mg KAEs/g) inhibitory activity of O. nana was found to be stronger than the other sample. (4) Conclusions: The chemical compositions and biological activities of the mentioned Onosma species were brought to the literature for the first time with this study. It is thought that O. nana can be an alternative source of phytochemicals in the food, pharmaceutical, and cosmetic industries due to its biological activity potential.

Temporal diversification in the genus Onosma (Boraginaceae) based on nuclear and plastid DNA sequences

The genus Onosma is a homogeneous taxon with high morphological variation and due to the similarities among the Onosma taxa, there are many problems in their identification. Hence, systematically and taxonomically, it is considered a difficult genus. In the present study, we included a large number of Onosma species throughout their distribution range. Using nuclear (ITS) and two plastids (rpl32-trnL(UAG) and trnH-psbA) markers, we analyzed the evolutionary history, divergence time and diversification patterns of Onosma across the tropical, subtropical and temperate regions. Divergence time estimates suggest the early radiation of Onosma s.l. happened at the Oligocene-Miocene boundary. BAMM analyses indicate that the best configuration included one significant shift in diversification rates within Onosma: on the branch leading to the clade comprised of species of confined to Iran.

Screening of cytotoxicity and DNA topoisomerase IIa inhibitory activity of Turkish Onosma species

Onosma L., the largest genus of Boraginaceae, is represented by 105 species in Turkey with an endemism rate of 52%. Phytochemical studies indicate that Boraginaceae plants mainly comprise naphthoquinones with a wide range of biological activities including anticancer, antiinflammatory, wound healing, and antioxidant effects. However, few taxa of the genus Onosma have been investigated in detail for their bioactivities. Considering the high rate of endemism and an inadequate number of bioactivity screening studies in literature, we aimed to evaluate the cytotoxic effects and topoisomerase inhibitory activities of some Onosma species growing in southwestern Turkey. Here, we describe a comprehensive cytotoxic activity screening study on petroleum ether, dichloromethane, and methanol extracts of the roots of 20 identified and one unidentified Onosma taxa. The MTT cell viability assay has been performed to investigate the cytotoxicity of the extracts against seven cancer cell lines (MCF-7, HeLa, Hep G2, A549, Capan-1, HCC-1937, and DU-145) and a noncancerous cell line (MRC-5), while doxorubicin was served as a positive standard. The petroleum ether extracts of O. aksoyii Aytaç&Türkmen, O. isaurica Boiss. and Heldr.,O. taurica Pallas ex Willd. var. taurica and O. alborosea Fisch. & C.A. Mey subsp. alborosea var. alborosea were determined as the most active ones based on their IC50 values. DNA topoisomerase II? inhibition assay was conducted on the petroleum ether and dichloromethane extracts of these four active species, and almost all tested extracts demonstrated strong inhibition on the enzyme at a concentration of 0.1 mg/mL. Our cytotoxicity screening results were consistent with the findings of the topoisomerase II? inhibition test. This study advocates the significant role of Onosma species in the field of anticancer drug discovery.

THE GENUS ONOSMA L.: A COMPREHENSIVE REVIEW

In medicinal plant field ethnopharmacological knowledge aggrandizes legibility for prioritizing species selection for future research opportunities. Many plant species representing the genus Onosma have been documented to be important in communities world-wide as evidenced by the numerous records on traditional medicinal and ethno-botanical information. Various species of the genus are used in the traditional medicinal systems in Europe and Asian countries especially in India, China, Turky and Pakistan. The literature on the species distribution and their characterization was compiled from different regional floras, regional revisions and databases. The information related to traditional uses, pharmacological activities and phytochemistry was systematically collected from the scientific databases including reference books, SciFinder, Scopus, PubMed and Google Scholar. Absence of comprehensive literature review on genus Onosma species led to design present study and dig the recorded documents to comparatively gauge magnitude of studies on each of the Onosma species through an exhaustive bibliographic evaluation of scientifically studied species of genus Onosma that are also taxonomically identified and are valued as traditional medicinal remedy for diseases in their countries of origin. The study hinted about lack of scientific literature on most of the species. A comprehensive bibliographic review on the geographical distribution, identification, traditional uses, phytochemistry, pharmacology and toxicology of the genus Onosma is attempted here to give insights into promising future drug discovery strategies. KEYWORDS: Onosma, Distribution, Traditional uses, Phyto-Pharmacology

Bioactive constituents, antioxidant effects and enzyme inhibitory properties of two Onosma species (Onosma trapezuntea and O. rigidum)

The genus Onosma is the biggest genus in the family Boraginaceae and its members are widely used for traditional purposes in several countries folk medicine. In the current work, two Onosma (O. trapezuntea and O. rigidum) species were examined for biological properties and chemical characterization. To evaluate biological properties, antioxidant and enzyme inhibitory assays were performed. Antioxidant assays included free radical scavenging (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH)), reducing power (cupric reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP)), metal chelating and phosphomolybdenum. Enzyme inhibitory were assessed against cholinesterase, tyrosinase, α-amylase and α-glucosidase. Total phenolic and flavonoid contents in O. trapezuntea were higher than those of O. rigidum. Liquid chromatography-mass spectrometry (LC-MS) analysis revealed that chlorogenic acid, rosmarinic acid and hyperoside were dominant compounds in the chemical profiles of the tested Onosma extracts. Generally, O. trapezuntea exhibited stronger antioxidant abilities than O. rigidum. However, the best chelating ability was recorded in O. rigidum. In addition, O. rigidum was more active on cholinesterase and α-glucosidase when compared with O. trapezuntea. The tested extracts exhibited similar tyrosinase inhibitory potentials. Consequently, our findings suggested that the tested Onosma species could be presented as valuable sources of natural ingredients such as antioxidant and enzyme inhibitors.

Onosma satensis sp. nov. (Boraginaceae: Lithospermeae), a new species from Hakkari (eastern Anatolia, Turkey)

A new species of Onosma L. (Boraginaceae: Lithospermeae), from the Hakkari province of eastern Turkey, is described and illustrated. The new species is endemic and distributed in a narrow area in the Sat Mountains. Taxonomically the closest relative of Onosma satensis sp. nov. is O. polioxantha Rech. f. which also occurs in Turkey. In addition, it is primarily distinguished from O. polioxantha by its navicular leaves, longer and reticulate cauline leaves, longer pedicels and calyx, longer and densely patent short setulose outside, reticulate corolla and bigger nutlets. The geographical distributions and map, detailed photographs, habitat description, vernacular name, an IUCN conservation status and identification key for O. satensis sp. nov. and O. polioxantha were also provided. Nutlets and pollen micrographs of O. satensis sp. nov. are presented using scanning electron microscopy.

Determination of the Chemical Composition, Antioxidant, and Enzyme Inhibitory Activity of Onosma mollis DC

Onosma species have long been used traditionally for respiratory tract infections, abdominal pain, wound treatment, burns, and constipation. This study aims to investigate the chemical composition and in vitro antioxidant and enzyme inhibitory activities of ethyl acetate (EtOAc), methanol (MeOH), and water extracts of Onosma mollis DC. MeOH extract was richer in both phenolics and flavonoids than other extracts (44.06 mg GAEs/g and 41.57 mg QEs/g, respectively). The findings obtained from the results of the chromatographic analysis also supported the results of the spectrophotometric analysis. The MeOH extract was the richest in terms of most of the phytochemicals screened. Apigenin 7-glucoside, luteolin 7-glucoside, rosmarinic acid, vanillic acid, and pinoresinol were over 1000.0 μg/g in MeOH extract. The extract in question showed the highest activity in phosphomolybdenum, DPPH, and ABTS radical scavenging and CUPRAC and FRAP reducing power activity assays (2.01, 3.33, 2.30, 1.48, and 0.79 mg/ml, respectively). The water extract presented the highest activity in the ferrous ion chelating assay (1.01 mg/ml). While EtOAc extract showed high activity in acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and α-glucosidase inhibitory activity tests (1.11, 1.49, and 1.07 mg/ml, respectively), MeOH extract showed significant efficacy in tyrosinase and α-amylase inhibitory activity assays (2.94 and 2.08 mg/ml, respectively). There was a high correlation between the total phenolics/flavonoids of the extracts and their antioxidant activities (correlation coefficients were over 0.9). In addition, the phytochemicals mentioned above were found to contribute significantly to the antioxidant activity. It was concluded that a more detailed analysis should be done to determine the compounds responsible for the enzyme inhibitory activities of the extracts.

Phytochemical Composition, Antioxidant, and Enzyme Inhibition Activities of Methanolic Extracts of Two Endemic Onosma Species.

Onosma species have been used as a dye for hundreds of years due to their dark red pigments. These species have also been used by mankind in the treatment of various diseases since ancient times. This work analyzed the phytochemical composition in methanol extract of two endemic Onosma species (O. lycaonica and O. papillosa). Methanolic extract of these species varied in the content of flavonoids and phenolics. The flavonoids were found higher in O. papillosa [32.9 ± 0.3 mg QEs (quercetin equivalent)/g extracts] while the phenolics were higher in O. lycaonica [43.5 ± 1.5 mg GAEs (gallic acid equivalent)/g extracts]. ESI-MS/MS (electrospray ionization-mass spectrometry) revealed the presence of 25 compounds in O. lycaonica and 24 compounds in O. papillosa. The former was richer than the latter for apigenin, luteolin, eriodictyol, pinoresinol, apigenin 7-glucoside, rosmarinic acid, luteolin 7-glucoside, ferulic acid, vanillin, caffeic acid, 4-hydroxybenzoic acid, (+)-catechin3,4-dihydroxyphenylacetic acid. The O. papillosa exhibited low EC50 (1.90 ± 0.07 mg/mL) which indicated its strong phosphomolybdenum scavenging activity as compared to O. lycaonica. However, the O. lycaonica showed low IC50 or EC50 for 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+), cupric reducing antioxidant power (CUPRAC), ferric reducing antioxidant power (FRAP) and ferrous ion chelating activity, as compared to O. papillosa. The results proved the presence of potent antioxidant compounds in O. lycaonica. Further, the plant extracts significantly varied for enzyme inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), but the plant extracts did not significantly differ for inhibition of α-glucosidase, α-amylase, and tyrosinase. Onosma species deserve further research towards developing novel drugs to treat oxidative diseases.

Nutraceutical extracts from some endemic Onosma ( O. ci rcinnata , O. bornmuelleri , and O. angustissima ) species: LC–ESI‐MS/MS–based polyphenol profile, antioxidant and enzyme inhibition activities

This study aimed to determine the chemical composition of methanol extracts from Onosma circinnata, Onosma bornmuelleri, and Onosma angustissima and to investigate their antioxidant and enzyme inhibitory activities. Spectrophotometric analysis showed that the extracts were found to be rich in chlorogenic acid, luteolin 7-glucoside, rosmarinic acid, and apigenin 7-glucoside. While O. bornmuelleri showed the highest activity in DPPH, ABTS, and FRAP tests, O. circinnata was more effective in CUPRAC, phosphomolybdenum, and ferrous ion chelating tests. While O. angustissima showed significant inhibitory activities on AChE, BChE, and tyrosinase, O. bornmuelleri and O. circinnata showed the highest inhibitory activities on α-amylase and α-glucosidase. It was concluded that O. circinnata and O. bornmuelleri are effective antioxidant agents and O. angustissima can be considered as an alternative agent in the medical and cosmetic industries due to its ChE and tyrosinase inhibitory activities. Novelty impact statement Biological activities of Onosma species were brought to the literature for the first time with this study. O. circinnata showed remarkable antioxidant activity. O. angustissima exhibited the highest AChE, BChE and tyrosinase inhibitory activity.

Chemical Composition, Antioxidant and Enzyme Inhibitory Activities of Onosma bourgaei and Onosma trachytricha and in Silico Molecular Docking Analysis of Dominant Compounds.

The aim of this study was to investigate the chemical composition, antioxidant and enzyme inhibitory activities of methanol (MeOH) extracts from Onosma bourgaei (Boiss.) and O. trachytricha (Boiss.). In addition, the interactions between phytochemicals found in extracts in high amounts and the target enzymes in question were revealed at the molecular scale by performing in silico molecular docking simulations. While the total amount of flavonoid compounds was higher in O. bourgaei, O. trachytricha was richer in phenolics. Chromatographic analysis showed that the major compounds of the extracts were luteolin 7-glucoside, apigenin 7-glucoside and rosmarinic acid. With the exception of the ferrous ion chelating assay, O. trachytricha exhibited higher antioxidant activity than O. bourgaei. O. bourgaei exhibited also slightly higher activity on digestive enzymes. The inhibitory activities of the Onosma species on tyrosinase were almost equal. In addition, the inhibitory activities of the extracts on acetylcholinesterase (AChE) were stronger than the activity on butyrylcholinesterase (BChE). Molecular docking simulations revealed that luteolin 7-glucoside and apigenin 7-glucoside have particularly strong binding affinities against ChEs, tyrosinase, α-amylase and α-glucosidase when compared with co-crystallized inhibitors. Therefore, it was concluded that the compounds in question could act as effective inhibitors on cholinesterases, tyrosinase and digestive enzymes.