In vitro and in silico evaluation of Ononis isoflavonoids as molecules targeting the central nervous system.

Isoflavonoids with various structural elements show a promising potential effect on central nervous system activities. Despite their favorable medicinal properties, the pharmacokinetic characteristics of this thoroughly investigated group of natural phenolics have only been described to a limited extent. Regarding the lack of information about the BBB permeability of isoflavones, isoflavanones, and pterocarpans found in Ononis species, the aim of our study was to investigate their physico-chemical properties influencing their absorption and distribution. Furthermore, we aimed to characterize the possible MAO-B inhibiting features of Ononis isoflavonoids in silico. Octanol-water partitioning and BBB-PAMPA permeability of formononetin, calycosin D, onogenin, sativanone, medicarpin and maackiain were assessed for the first time in our study. The log P values ranged from 2.21 to 3.03 and log D7.4 values from 2.48 to 3.03, respectively, indicating optimal polarity for BBB permeation. The results of PAMPA-BBB expressed as log Pe values fell between -5.60 and -4.45, predicting their good permeation capability as well. The effective permeability values showed structure-dependent differences, indicating that the pterocarpan type skeleton was the most preferred type, followed by isoflavanones, then isoflavones. The methoxy or methylenedioxy substitution of the same skeleton did not influence the permeability significantly, contrary to an additional hydroxyl group. Membrane retention showed a similar structure dependent pattern to that of effective permeability, ranging from 16% to 70%. For the identification of volumes of chemical space related to particular biological activities the ChemGPS-NP framework was used. The MAO-B inhibitory potency and selectivity were also predicted and validated. Based on our results, MAO-B inhibitory potency could be predicted with good precision, but in the case of selectivity, only the direction could be concluded (favors MAO-B or MAO-A), not the magnitude. Our finding reflects that Ononis isoflavonoid aglycones show an excellent fit with the suggested parameters for BBB permeability and this is the first study to confirm the highly favorable position of these natural products for MAO-B inhibition.

Efficacy of extract from Ononis spinosa L. on ethanol-induced gastric ulcer in rats.

OBJECTIVE: To investigate the efficacy of the extract from Ononis spinosa L. (O. spinosa) on ethanol-induced gastric ulcer in rats. METHODS: Phytochemical constituents of the extract from O. spinosa were analyzed using liquid chromatography-mass spectrometry. Rats were classified into 4 equal groups; ulcer control received oral vehicle; positive control was administered with 40 mg/kg esomeprazole (standard drug) and 2 groups received 0.5 and 1 g/kg of O. spinosa extract, respectively. Gastric ulcer was induced by absolute ethanol (5 mL/kg) orally to all groups. Measurement of ulcer index, cyclooxygenase-2 (COX-2) expression and determination of total glutathione level in gastric mucosa were performed. RESULTS: Oral administration of the extract from O. spinosa at doses 0.5 and 1 g/kg lowered the ulcer indices by 80.39% and 98.71% , respectively, compared to 67.89% by esomeprazole (40 mg/kg). Histologically, treatment with the extract decreased necrosis and hemorrhage in mucosa and edema and infiltration by inflammatory cells in submucosa. Using immunohistochemical technique, it was demonstrated that COX-2 expression increased in mucosa of animals treated with the extract as well as by esomeprazole. O. spinosa and esomeprazole increased total glutathione level in the stomach compared to control. Ononin was the major compound of the extract followed by trifolirhizin, myricitrin, gentisic acid, cycloartenol and quercetin. CONCLUSION: The present study demonstrated that the extract from O. spinosa was able to protect gastric mucosa from ethanol injury by at least 2 mechanisms, namely the induction of COX-2 and decreasing oxidative stress in the stomach.

Ononis spinosa L., an edible and medicinal plant: UHPLC-LTQ-Orbitrap/MS chemical profiling and biological activities of the herbal extract.

This study explored the chemical profile of the aerial parts of Ononis spinosa and further investigated its biological activities. Chemical profiling of the extract revealed the presence of 63 different compounds: phenolic acids, flavonoid glycosides and aglycones, isoflavonoid glycosides and aglycones, and other related compounds. Our results revealed that the extract was active against 8 strains of free floating bacteria. It showed anti-biofilm potential against Staphylococcus aureus and was able to supress the production of staphyloxanthin in S. aureus at sub-minimal inhibitory concentrations. Its antioxidant activity was evaluated by using several assays (phosphomolybdenum, DPPH, ABTS, CUPRAC, FRAP, and metal chelating assay), which showed that the extract exhibited a dose dependent activity. Inhibition of AChE, BChE, amylase, glucosidase and tyrosinase was achieved by the extract, demonstrating its anti-enzymatic activity. The antiproliferative potential of the extract towards human cancer cell lines (HepG2, MCF-7, SiHa and A172) was determined by using the crystal violet assay. Ki67, a marker of proliferation was downregulated in the A172 glioblastoma cell line.

Isoflavonoids with inhibiting effects on human hyaluronidase-1 and norneolignan clitorienolactone B from Ononis spinosa L. root extract.

Human hyaluronidase-1 (Hyal-1) is one of the main enzymes in the homeostasis of hyaluronic acid (HA), the main polysaccharide of extracellular matrix. Development of specific Hyal-1 inhibitors might be a promising target for improved wound healing, tissue regeneration, and looking at renal function for diuresis. By using surface-displayed Hyal-1 on Escherichia coli F470 cells, HA as substrate and stains-all method for quantification of undegraded HA, the respective enzyme activity can be determined easily. Based on the traditional use of extracts from the roots from Ononis spinosa L. (Restharrow root) as a weak diuretic to achieve flushing of the urinary tract and as an adjuvant in minor urinary complaints the herbal material was selected for bioactivity guided fractionation for compounds with Hyal-1 inhibition activity. Hot water and hydroalcoholic extracts showed moderate inhibiting effects (IC50 1.36 resp. 0.73 mg/mL) while dichloromethane extract exerted an IC50 of 190 µg/mL. Bioassay guided fractionation of the dichloromethane extract yielded four isoflavonoids with anti Hyal-1 activity: onogenin 1, sativanone 2, medicarpin 3 and calycosin-D 4 with inhibition rates of 25.4, 61.2, 22.4 and 23.0%, respectively at test concentration level of 250 µM. The norneolignan clitorienolactone B 5, the first time described for the genus Ononis, was inactive. The IC50 of sativanone, the most active compound was determined with 1501 µM, which was better than that of the positive control glycyrrhizinic acid (177 µM). Thus, a possible explanation for diuretic properties of Ononis spinosa L. root extract may be postulated from the results so far obtained.

Separation and characterization of homopipecolic acid isoflavonoid ester derivatives isolated from Ononis spinosa L. root.

Spiny restharrow root (Ononis spinosa L.) and its preparations are mainly used for the treatment of urinary infections or bladder stones in numerous countries. Spiny restharrow root is rich in isoflavonoids (formononetin, calycosin and pseudobaptigenin), pterocarpans (medicarpin and maackiain) and dihydroisoflavonoids (onogenin and sativanone), which metabolites are present as glucosides, glucoside malonates, glucoside acetates and free aglycones in the root. The in-depth analysis of tandem mass spectrometric (MS) and high-resolution MS (HR-MS) data revealed the presence of nitrogen-containing compounds in the root extracts. An ion-exchange-based purification and a preparative-scale reversed phase chromatographic isolation procedure was developed for the characterization of these new natural products. For the unambiguous identification of the isolated compounds NMR experiments were carried out. The thorough characterization confirmed the presence of six piperidin-2-yl-acetic acid (homopipecolic acid) esters of isoflavonoid glucosides. This is the first report of homopipecolic acid esters isolated from higher plants.

A Single Oxidosqualene Cyclase Produces the Seco-Triterpenoid α-Onocerin.

8,14-seco-Triterpenoids are characterized by their unusual open C-ring. Their distribution in nature is rare and scattered in taxonomically unrelated plants. The 8,14-seco-triterpenoid α-onocerin is only known from the evolutionarily distant clubmoss genus Lycopodium and the leguminous genus Ononis, which makes the biosynthesis of this seco-triterpenoid intriguing from an evolutionary standpoint. In our experiments with Ononis spinosa, α-onocerin was detected only in the roots. Through transcriptome analysis of the roots, an oxidosqualene cyclase, OsONS1, was identified that produces α-onocerin from squalene-2,3;22,23-dioxide when transiently expressed in Nicotiana bethamiana In contrast, in Lycopodium clavatum, two sequential cyclases, LcLCC and LcLCD, are required to produce α-onocerin in the N. benthamiana transient expression system. Expression of OsONS1 in the lanosterol synthase knockout yeast strain GIL77, which accumulates squalene-2,3;22,23-dioxide, verified the α-onocerin production. A phylogenetic analysis predicts that OsONS1 branches off from specific lupeol synthases and does not group with the known L. clavatum α-onocerin cyclases. Both the biochemical and phylogenetic analyses of OsONS1 suggest convergent evolution of the α-onocerin pathways. When OsONS1 was coexpressed in N. benthamiana leaves with either of the two O. spinosa squalene epoxidases, OsSQE1 or OsSQE2, α-onocerin production was boosted, most likely because the epoxidases produce higher amounts of squalene-2,3;22,23-dioxide. Fluorescence lifetime imaging microscopy analysis demonstrated specific protein-protein interactions between OsONS1 and both O. spinosa squalene epoxidases. Coexpression of OsONS1 with the two OsSQEs suggests that OsSQE2 is the preferred partner of OsONS1 in planta. Our results provide an example of the convergent evolution of plant specialized metabolism.

Histological and antimicrobial study of Ononis arvensis L.

In this study field restharrow (Ononis arvensis) was investigated for histological and antimicrobial features. The aerial part and the root were embedded in synthetic resin and investigated following sectioning by a rotation microtome. The antimicrobial activity and minimum inhibitory concentration of the solvent fractions of the aerial part were studied against four bacterial strains and one fungus. According to histology, the root covered by rhizodermis contains contiguous vascular elements, which are surrounded by sclerenchyma cells. The epidermis cells are anisodiametric in the stem, sepal, and petal. The bundles of the stem form a Ricinus type thickening. The adaxial side of the heterogeneous leaf is covered by unbranching non-glandular and capitate glandular trichomes. The stipule, petiole, sepals and petals are isolateral having mesomorphic stomata. Pollen grains are tricolpate. The different extracts of the herb showed antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Salmonella Typhimurium, Staphylococcus aureus, and Candida albicans. Data show that the extracts of the leaf contain compounds which may be responsible for the antifungal effect, while extracts obtained from display against the tested bacteria, except Escherichia coli. Further studies are required to complete the phytochemical analysis and identify the antimicrobial compounds of extracts.

Wound healing and anti-inflammatory activity of some Ononis taxons.

Ononis species are used for their laxative, diuretic, analgesic, anti-inflammatory, antiviral, cytotoxic and antifungal effects as well as against skin diseases for wound healing activity. In the light of this information n-hexane, ethylacetate and methanol extracts prepared from Ononis spinosa L. subsp. leiosperma (Boiss.) Sirj., Ononis variegata L., Ononis viscosa L. subsp. brevifolia (DC) Nym. and Ononis natrix L. subsp. natrix L. were tested for their wound healing, anti-inflammatory and antioxidant activities. Linear incision and circular excision wound models and hydroxypyroline estimation assay were used for the wound healing activity. For the assessment of chronic inflammation FCA-induced arthritis and for acute inflammation carrageenan-induced hind paw edema, TPA-induced ear edema and acetic acid-induced increase in capillary permeability tests were conducted. 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, 2,2-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) scavenging activity assay, reducing power assay and hydroxyl radical (OH-) scavenging assay were used for determining antioxidant activities of the extracts. Results showed that O. spinosa subsp. leiosperma roots ethyl acetate extract exhibited remarkable wound healing activity with the 42.6% tensile strength value on the linear incision wound model and 60.1% reduction of the wound area at the day 12 on the circular excision wound model. Hydroxyproline content of the tissue treated by O. spinosa subsp. leiosperma roots ethyl acetate extract was found to be 41.3µg/mg. Acetic acid induced increase in capillary permeability test results revealed that O. spinosa subsp. leiosperma roots ethyl acetate extract and O. spinosa subsp. leiosperma roots methanol extract inhibited inflammation by 40.4% and 35.4% values respectively. O. spinosa subsp. leiosperma roots ethyl acetate extract showed 21.2-27.2% inhibition in carrageenan-induced hind paw edema test while did not posses activity on TPA-induced ear edema and FCA-induced arthritis models.

Phytochemical and antioxidant activity studies on Ononis angustissima L. aerial parts: isolation of two new flavonoids.

Ononis angustissima aerial parts extract and exudate were subjected to phytochemical and biological studies. Two new natural flavonoids, (3S)-7-hydroxy-4'-methoxy-isoflavanone 3'-ß-d-glucopyranoside (1) and kaempferol 3-O-ß-d-glucopyranoside-7-O-(2'''-acetyl)-ß-d-galactopyranoside (4), and sixteen known compounds were isolated through a bio-oriented approach. Their structural characterisation was achieved using spectroscopic analyses including 2D NMR. The phytochemical profile of the extracts was also performed, and the antioxidant activity of all compounds was tested by three different assays. To get a trend in the results and to compare the antioxidant capacity among the different methods used, the obtained data were transformed to a relative antioxidant capacity index.

Chemical composition of the essential oil from the aerial parts of Ononis reclinata L. (Fabaceae) grown wild in Sicily.

In the present study, the chemical composition of the essential oil from aerial parts of Ononis reclinata L., a species not previously investigated, collected in Sicily was evaluated by GC and Gas chromatography-Mass spectrometry. The main components of O. reclinata were menthone (43.6%), isopimpinellin (38.4%) and pulegone (11.2%). The comparison with other studied oils of genus Ononis showed a peculiar and characteristic profile.

Characterization and identification of isoflavonoid glycosides in the root of Spiny restharrow (Ononis spinosa L.) by HPLC-QTOF-MS, HPLC-MS/MS and NMR.

Restharrow root has been used in traditional medicine for thousands of years; however, the active ingredients responsible for the diuretic effect are still unknown. Previous studies have proved that the root extract contains isoflavonoids, however only few derivatives were identified, mostly relying on retention times or UV data. The aim of our work was to perform a detailed structural characterization of the complete isoflavonoid profile in the aqueous-methanolic extract of Ononis spinosa root by high-performance liquid chromatography coupled with electrospray ionization accurate-mass quadrupole time-of-flight and tandem mass spectrometry in positive ionization mode (HPLC-ESI-QTOF-MS, HPLC-ESI-MS/MS) and nuclear magnetic resonance spectroscopy (NMR). On the basis of the accurate masses and fragmentation patterns isoflavones (formononetin, calycosin and pseudobaptigenin) and pterocarpans (maackiain and medicarpin) were identified. Two further dihydroisoflavone aglycones, namely onogenin and sativanone and a unique glucoside were isolated and their structures were elucidated by NMR experiments. Calycosin, onogenin and sativanone were detected in this plant for the first time. In contrast to previous works, the presence of biochanin A could not be confirmed, however its regioisomer calycosin and its derivatives were identified. Similarly, neither tectorigenin derivatives could be detected, however the isobar compound sativanone and its various glucosides were elucidated. The presence of genistein and daidzein could not be confirmed in the extract. Fragmentation pathways for onogenin and sativanone are presented. In the aqueous-methanolic extract 9 glucosides, 6 minor and 8 major glucoside malonates, 4 glucoside acetates and 7 aglycones were found. In total, 34 compounds were successfully identified.

Isolation and structure elucidation of bioactive compounds from the roots of the Tunisian Ononis angustissima L.

A phytochemical investigation of the roots of Ononis angustissima L. (Fabaceae) offered to the bio-guided isolation of new isoflavone 3-(4-(glucopyranosyloxy)-5-hydroxy-2-methoxyphenyl)-7-hydroxy-4H-chromen-4-one 1, together with nine known compounds, ononin 2, formononetin 3, (+)-puerol A-2'-O-ß-D-glucose 4, (-)-puerol B-2'-O-ß-D-glucopyranose ((-)-sophoraside A) 5, (+)-puerol A 6, (-)-trifolirhizin 7, (-)-trifolirhizin-6'-O-malonate 8, (-)-maackiain 9 and (-)-medicarpin 10. Compounds 2-10 were isolated and identified for the first time in Ononis angustissima. We investigated antioxidant capacities of isolated molecules and results showed that compound 6 exhibited the highest antioxidant activity with IC50 values of 19.53 µg/mL, 28.29 µg/mL and 38.53 µg/mL by DPPH radical, ABTS radical cation and reducing power assay, respectively, and an interesting IC50 (20.45 µg/mL) of 1 against DPPH. In addition, the neuroprotective activity of six isolated molecules (4-7, 9, 10) were evaluated. Following the exposure of PC12 cells to Aß25-35, compounds 9 and 10 triggered a significant increase of cell viability and in a dose dependent manner.