A new cyclic polyketide and other constituents from Ononis spinosa growing wildly in Jordan and their antioxidant activity

The new cyclic polyketide 7,9,11-trihydroxytetracos-2-eneoic acid δ-lactone (1), together with other eleven known compounds, were isolated from Ononis spinosa, growing wildly in Jordan. All isolated compounds were identified by thorough investigation of their spectral data including NMR and HRESIMS. Antioxidant activity testing of puerol B, specionin and the new cyclic polyketide revealed that puerol B had the highest DPPH radical scavenging activity (IC₅₀ 0.09 ± 0.006 mg/ml) as compared to α-tocopherol (IC₅₀ 0.039 ± 0.0006 mg/ml), while specionin had the highest ABTS radical scavenging power (IC₅₀ 0.013 ± 0.0008 mg/ml) as compared to α-tocopherol and ascorbic acid (IC₅₀ 0.042 ± 0.0004; 0.026 ± 0 .0007 mg/ml; respectively).

Quantitative determination of isoflavonoids in Ononis species by UPLC-UV-DAD

INTRODUCTION

The root of the Ononis species has been used internally and externally in ethnomedicine for centuries and contains biologically valuable isoflavonoid compounds. Therefore, it is important to obtain quantitative information about the isoflavonoid profile of these plants.

OBJECTIVES

In this article we aimed to develop an optimised sample preparation protocol alongside a validated method for the quantitative measurement of isoflavones, isoflavanones and pterocarpans in the form of glucosides and aglycones, in order to compare the specialised metabolites of Ononis spinosa L. and O. arvensis L.

MATERIAL AND METHODS

Quantitative determination was carried out by the means of ultra-performance liquid chromatography coupled with ultraviolet diode-array detection (UPLC-UV-DAD).

RESULTS

An optimised sample preparation method was developed to transform malonyl glucosides to their glucosidic forms. Chromatographic methods were created for the baseline separation of isoflavones, isoflavanones and pterocarpans alongside with their glucosides. Altogether 12 compounds were evaluated quantitatively in samples of O. spinosa and O. arvensis.

CONCLUSION

As a result, no characteristic change could be observed between the two species regarding their isoflavonoid pattern.

Aqueous Root Extract from Ononis spinosa Exerts Anti-adhesive Activity against Uropathogenic Escherichia coli

Extracts from Ononis spinosa are traditionally used for urinary tract infections due to diuretic and anti-inflammatory activity. A potential influence on the virulence of uropathogenic Escherichia coli has not been investigated until now. The following study aimed to investigate the influence of an aqueous O. spinosa extract on uropathogenic E. coli and uropathogenic E. coli host cell interaction. A hot water extract from the roots of O. spinosa (O. spinosa extract) was characterized by LC-qTOF-MS. The influence of O. spinosa extract on the proliferation of uropathogenic E. coli UTI89 and on cell viability against human T24 bladder cells was investigated. Anti-adhesive activity of O. spinosa extract was assessed by flow cytometry, evaluating the adhesion of fluorescent-labelled UTI89 to T24 bladder cells. Internalization of uropathogenic E. coli into T24 cells was monitored by an invasion assay. O. spinosa extract was characterized by the presence of isoflavones, isoflavanones, licoagrosides, pterocarpans, tartaric acid derivatives, and saponines. O. spinosa extract had no influence on the proliferation of uropathogenic E. coli (125 - 1000 µg/mL) and did not influence the cell viability of T24 cells. Bacterial adhesion to T24 cells was significantly (p > 0.001) inhibited by O. spinosa extract in a concentration-dependent manner (125 - 1000 µg/mL) during coincubation. Preincubation of uropathogenic E. coli or T24 cells with O. spinosa extract reduced bacterial adhesion, but to a lower extent than during coincubation. Consequently, the reduced bacterial adhesion also leads to a reduced internalization of uropathogenic E. coli uropathogenic E. coli into the host cell. O. spinosa extract does not interact with FimH-mediated uropathogenic E. coli adhesion to host cells. From these data, the traditional use of O. spinosa extracts for urinary tract infections seems to be rationalized.