Flavonoids from Artemisia rupestris and their synergistic antibacterial effects on drug-resistant Staphylococcus aureus.

This study seeks to discover flavonoids from a traditional Chinese herb, Artemisia rupestris L., with synergistic antibacterial effects against multidrug-resistant Staphylococcus aureus. Five flavonoids, artemetin (1), chrysosplenetin (2), pachypodol (3), penduletin (4) and chrysoeriol (5) were obtained by various column chromatographic methods. Their chemical structures were determined on the basis of comprehensive spectroscopic analysis and comparison with literature data. Three of the compounds (2, 4 and 5) exhibited synergistic activity when combined with norfloxacin against SA1199B, an effluxing fluoroquinolone-resistant strain. The fractional inhibitory concentration indices (FICIs) of 2, 4 and 5 in combination with norfloxacin were 0.375, 0.079 and 0.266 respectively, suggesting synergy. Compound 5 also showed synergistic effects against EMRSA-15 and EMRSA-16 when combined with ciprofloxacin and oxacillin exhibiting FICIs of 0.024 and 0.375 respectively. Real time ethidium bromide (EtBr) efflux assay, qRT-PCR and molecular docking were employed to explore the mechanisms of the synergistic effects.

Intended and unintended use of cathinone mixtures.

INTRODUCTION: Cathinones are one of the most popular categories of new psychoactive substances (NPS) consumed. Cathinones have different pharmacological activities and receptor selectivity for monoamine transporters based on their chemical structures. They are incorporated into NPS mixtures and used with other NPS or 'traditional' drugs. Cathinone use represents significant health risks to individuals and is a public health burden. METHODS: Evidence of poly-NPS use with cathinones, seizure information, and literature analyses results on NPS mixtures was systematically gathered from online database sources, including Google Scholar, Scopus, Bluelight, and Drugs-Forum. RESULTS AND DISCUSSION: Results highlight the prevalence of NPS with low purity, incorporation of cathinones into NPS mixtures since 2008, and multiple members of the cathinone family being present in individual UK-seized samples. Cathinones were identified as adulterants in NPS marketed as being pure NPS, drugs of abuse, branded products, herbal blends, and products labelled "not for human consumption." Toxicity resulting from cathinone mixtures is unpredictable because key attributes remain largely unknown. Symptoms of intoxication include neuro-psychological, psychiatric, and metabolic symptoms. Proposed treatment includes holistic approaches involving psychosocial, psychiatric and pharmacological interventions. CONCLUSION: Raising awareness of NPS, education, and training of health care professionals are paramount in reducing harms related to cathinone use.

Application of diffusion-edited and solvent suppression ¹H-NMR to the direct analysis of markers in valerian-hop liquid herbal products.

INTRODUCTION: The rising trend to consume herbal products for the treatment and/or prevention of minor ailments together with their chemical and pharmacological complexity means there is an urgent need to develop new approaches to their quality and stability. OBJECTIVES: This work looks at the application of one-dimensional diffusion-edited (1)H-NMR spectroscopy (1D DOSY) and (1)H-NMR with suppression of the ethanol and water signals to the characterisation of quality and stability markers in multi-component herbal medicines/food supplements. MATERIAL AND METHODS: The experiments were performed with commercial tinctures of Valeriana officinalis L. (valerian), expired and non-expired, as well as its combination with Hummulus lupulus L. (hops), which is one of the most popular blends of relaxant herbs. These techniques did not require purification or evaporation of components for the qualitative analysis of the mixture, but only the addition of D2 O and TSP. RESULTS: The best diagnostic signals were found at δ 7 ppm (H-11, valerenic acid), δ 4.2 ppm (H-1, hydroxyvalerenic acid) and δ 1.5-1.8 ppm (methyl groups in prenylated moieties, α-acids/prenylated flavones). CONCLUSION: This work concludes on the potential value of 1D DOSY (1)H-NMR to provide additional assurance of quality in complex natural mixtures.

A phytochemical comparison of saw palmetto products using gas chromatography and (1) H nuclear magnetic resonance spectroscopy metabolomic profiling.

OBJECTIVES: Preparations containing saw palmetto berries are used in the treatment of benign prostatic hyperplasia (BPH). There are many products on the market, and relatively little is known about their chemical variability and specifically the composition and quality of different saw palmetto products notwithstanding that in 2000, an international consultation paper from the major urological associations from the five continents on treatments for BPH demanded further research on this topic. Here, we compare two analytical approaches and characterise 57 different saw palmetto products. METHODS: An established method - gas chromatography - was used for the quantification of nine fatty acids, while a novel approach of metabolomic profiling using (1) H nuclear magnetic resonance (NMR) spectroscopy was used as a fingerprinting tool to assess the overall composition of the extracts. KEY FINDINGS: The phytochemical analysis determining the fatty acids showed a high level of heterogeneity of the different products in the total amount and of nine single fatty acids. A robust and reproducible (1) H NMR spectroscopy method was established, and the results showed that it was possible to statistically differentiate between saw palmetto products that had been extracted under different conditions but not between products that used a similar extraction method. Principal component analysis was able to determine those products that had significantly different metabolites. CONCLUSIONS: The metabolomic approach developed offers novel opportunities for quality control along the value chain of saw palmetto and needs to be followed further, as with this method, the complexity of a herbal extract can be better assessed than with the analysis of a single group of constituents.

Antibacterial acylphloroglucinols from Hypericum olympicum.

New antibacterial acylphloroglucinols (1-5) were isolated and characterized from the aerial parts of the plant Hypericum olympicum L. cf. uniflorum. The structures of these compounds were confirmed by extensive 1D- and 2D-NMR experiments to be 4,6-dihydroxy-2-O-(3″,7″-dimethyl-2″,6″-octadienyl)-1-(2'-methylbutanoyl)benzene (1), 4,6-dihydroxy-2-O-(7″-hydroxy-3″,7″-dimethyl-2″,5″-octadienyl)-1-(2'-methylbutanoyl)benzene (2), 4,6-dihydroxy-2-O-(6″-hydroxy-3″,7″-dimethyl-2″,7″-octadienyl)-1-(2'-methylbutanoyl)benzene (3), 4,6-dihydroxy-2-O-(6″-hydroperoxy-3″,7″-dimethyl-2″,7″-octadienyl)-1-(2'-methylbutanoyl)benzene (4), and 4,6-dihydroxy-2-O-(6″,7″-epoxy-3″,7″-dimethyloct-2″-enyl)-1-(2'-methylbutanoyl)benzene (5). These new natural products have been given the trivial names olympicins A-E (1-5). All compounds were evaluated against a panel of methicillin-resistant Staph. aureus and multidrug-resistant strains of Staph. aureus. Compound 1 exhibited minimum inhibitory concentrations (MICs) of 0.5-1 mg/L against the tested Staph. aureus strains. Compounds 2 to 5 were also shown to be active, with MICs ranging from 64 to 128 mg/L. Compound 1 was synthesized using a simple four-step method that can be readily utilized to give a number of structural analogues of 1.

Direct metabolic fingerprinting of commercial herbal tinctures by nuclear magnetic resonance spectroscopy and mass spectrometry.

INTRODUCTION: Tinctures are widely used liquid pharmaceutical preparations traditionally obtained by maceration of one or more medicinal plants in ethanol-water solutions. Such a process results in the extraction of virtually hundreds of structurally diverse compounds with different polarities. Owing to the large chemical diversity of the constituents present in the herbal tinctures, the analytical tools used for the quality control of tinctures are usually optimised only for the detection of single chemical entities or specific class of compounds. OBJECTIVE: In order to overcome the major limitations of the current methods used for analysis of tinctures, a new methodological approach based on NMR spectroscopy and MS spectrometry has been tested with different commercial tinctures. METHODOLOGY: Diffusion-edited 1H-NMR (1D DOSY) and 1H-NMR with suppression of the ethanol and water signals have been applied here for the first time to the direct analysis of commercial herbal tinctures derived from Echinacea purpurea, Hypericum perforatum, Ginkgo biloba and Valeriana officinalis. The direct injection of the tinctures in the MS detector in order to obtain the corresponding metabolic profiles was also performed. RESULTS: Using both NMR and MS methods it was possible, without evaporation or separation steps, to obtain a metabolic fingerprint able to distinguish between tinctures prepared with different plants. Batch-to-batch homogeneity, as well as degradation after the expiry date of a batch, was also investigated. CONCLUSION: The techniques proposed here represent fast and convenient direct analyses of medicinal herbal tinctures.

Isopimaric acid from Pinus nigra shows activity against multidrug-resistant and EMRSA strains of Staphylococcus aureus.

The diterpene isopimaric acid was extracted from the immature cones of Pinus nigra (Arnold) using bioassay-guided fractionation of a crude hexane extract. Isopimaric acid was assayed against multidrug-resistant (MDR) and methicillin-resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentrations (MIC) were 32-64 microg/mL and compared with a commercially obtained resin acid, abietic acid, with MICs of 64 microg/mL. Resin acids are known to have antibacterial activity and are valued in traditional medicine for their antiseptic properties. These results show that isopimaric acid is active against MDR and MRSA strains of S. aureus which are becoming increasingly resistant to antibiotics. Both compounds were evaluated for modulation activity in combination with antibiotics, but did not potentiate the activity of the antibiotics tested. However, the compounds were also assayed in combination with the efflux pump inhibitor reserpine, to see if inhibition of the TetK or NorA efflux pump increased their activity. Interestingly, rather than a potentiation of activity by a reduction in MIC, a two to four-fold increase in MIC was seen. It may be that isopimaric acid and abietic acid are not substrates for these efflux pumps, but it is also possible that an antagonistic interaction with reserpine may render the antibiotics inactive. 1H-NMR of abietic acid and reserpine taken individually and in combination, revealed a shift in resonance of some peaks for both compounds when mixed together compared with the spectra of the compounds on their own. It is proposed that this may be due to complex formation between abietic acid and reserpine and that this complex formation is responsible for a reduction in activity and elevation of MIC.