Contribution of individual flavonoids in Lysimachia species to the antioxidant capacity based on HPLC-DPPH assay.

Quantitative phytochemical characterisation of the chief flavonoid aglycones in the hydrolysed Lysimachia extracts revealed the dominance of kaempferol, quercetin and myricetin in L. vulgaris, L. nummularia, L. punctata, L. christinae, L. ciliata and L. clethroides, respectively. Due to the significant radical scavenging capacity of the samples, the contribution of the individual aglycones to the total antioxidant activity became of interest. Therefore, a HPLC method coupled to pre-column DPPH scavenging assay was developed. Differences in the six Lysimachia species' phenolic composition regarding their participation to the antioxidant activity were revealed. The participation of the three investigated flavonoids to the radical quenching activity was the highest (91.2%) in the L. vulgaris sample, the lowest in L. christinae sample with 29.6%. In L. vulgaris sample, the 76.3% contribution of quercetin to the scavenger capacity was the highest peak area decrement ratio among the investigated samples.

Three newly identified lipophilic flavonoids in Tanacetum parthenium supercritical fluid extract penetrating the Blood-Brain Barrier.

Feverfew (Tanacetum parthenium L.) as a perennial herb has been known for centuries due to its medicinal properties. The main sesquiterpene lactone, parthenolide is considered to be responsible for the migraine prophylactic effect, however the pharmacological benefits of the lipophilic flavonoid components can not be neglected. Supercritical fluid extraction (7% ethanol, 22MPa, 64°C) was carried out on the leaves of Tanacetum parthenium L. from which the presence of methylated flavonoids beside parthenolide and other sesquiterpene lactones were indicated by preliminary LC-MS analyses. Specific Parallel Artificial Membrane Permeability Assay (PAMPA) was applied to identify the components capable to cross the Blood-Brain Barrier (BBB). Three lipophilic flavonoids were detected on the acceptor side, that were isolated (Prep-HPLC) and identified as sudachitin, aceronin and nevadensin (LC-MS/MS, NMR). These flavonoids were also characterized individually by PAMPA-BBB model. The presence of sudachitin and nevadensin was proven in the Asteraceae family, but neither of the three flavonoids were reported in Tanacetum parthenium L.

Convergence chromatographic determination of camphor in the essential oil of Tanacetum parthenium L.

Feverfew (Tanacetum parthenium L., Asteraceae) is a perennial medicinal plant which has been used to alleviate the symptoms of migraine, headache and rheumatoid arthritis and possesses numerous pharmacological activities. An ultra-high-performance supercritical fluid chromatographic method (UHPSFC) was developed and validated in accordance with the International Conference on Harmonization guidelines in order to determine the camphor content of the volatile oil, which was accurate, precise, robust and selective. The method was validated for specificity, accuracy (100.2%), repeatability and intermediate precision, linearity (r2 > 0.999), limit of detection (2.055 µg/mL), limit of quantification (6.228 µg/mL) and robustness. The common range of accuracy and linearity was between 0.125 and 1.000 mg/mL. Steam distillation was carried out in order to study the essential oil yield of three different T. parthenium L. samples originating from Hungarian medicinal herb collections. The camphor content of the essential oils from the aerial parts of feverfew samples from different origin was compared. Although the composition of the essential oil is well reported, a validated quantitative UHPSFC method for the determination of the constituents is presented herein for the first time.

HPLC-DPPH Screening Method for Evaluation of Antioxidant Compounds in Corylus Species.

Corylus avellana L., C. colurna L. and C. maxima Mill. have been used in traditional medicine for a long time for the treatment of various diseases, such as phlebitis, varicose veins, haemorrhoidal symptoms and eczema. Our previous studies indicated the presence of flavonol-3-O-glycosides, diarylheptanoids and caffeic acid derivatives in the bark and leaf extracts of the three species mentioned above. Comparison of in vitro DPPH scavenging activity of the Corylus extracts prepared with ethyl acetate and methanol to those of well-known antioxidant phenolics was performed. The contribution of certain compounds to the total antioxidant activity of the extracts was investigated by developing a HPLC method coupled to the DPPH radical scavenging assay.

A new ultra-high pressure liquid chromatography method for the determination of antioxidant flavonol aglycones in six Lysimachia species.

UPLC-DAD method was developed and validated for the quantitative determination of free flavonol aglycones (kaempferol, quercetin and myricetin) after acidic hydrolysis in six Lysimachia species. Quantitative analyses showed that the amounts of various flavonol aglycones were significantly different in Lysimachia vulgaris, Lysimachia nummularia, Lysimachia punctata, Lysimachia christinae, Lysimachia ciliata and Lysimachia clethroides. The L. clethroides sample was found to be the richest in kaempferol (25.77 ± 1.29 µg/mg extract) and quercetin (97.67 ± 4.61 µg/mg extract), while the L. nummularia sample contained the highest amount of myricetin (20.79 ± 1.00 µg/mg extract). The antioxidant capacity of hydrolysed extracts was evaluated using in vitro DPPH(•) (2,2-diphenyl-1-picrylhydrazyl) and ABTS(•+) [2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid)] decolourisation tests. The observed radical scavenging capacities of the extracts showed a relationship with the measured flavonol aglycone content and composition. The acidic treatment resulted in an increased free radical scavenging activity compared to the untreated methanol extract.

[Occurence of diarylheptanoids in Corylus species native to Hungary]. / Diarilheptanoidok elofordulása a mogyoró nemzetség Kárpát-medencében honos fajaiban.

Since the last decade naturally occurring diarylheptanoids have been in the focus of scientific interest due to their various. beneficial biological effects. Besides the outstanding importance of the curcuminoids isolated from members of the Curcuma genus (Zingiberaceae), several different diarylheptanoids identified in Alnus species (Betulaceae) have been proved to possess notable pharmacological effects. Chemoprotective, neuroprotective, hepatoprotective, antiviral, antibacterial, antiinflammatory and antioxidant activities suggest their potential role in clinical practice. The aim of our study was the phytochemical investigation of the Corylus (Betulaceae) species native to Hungary: the Common hazel (Corylus avellana L.), the Turkish hazel (Corylus colurna L.) and the Filbert (Corylus maxima Mill.) in order to characterise their phenolic-profile. Although these plants have been used in traditional medicine for long time, literature data regarding their phytochemical composition is limited to the flavonoid and hydroxycinnamic-acid derivatives of C. avellana leaves. No previous studies have been published reporting the presence of diarylheptanoid compounds in any of the Corylus species. Soxhlet extraction with solvents of increasing polarity was performed on the bark and leaves of the mentioned three Corylus species. The phenolic-profile of the methanolic and ethyl acetate extracts was investigated by HPLC-DAD-ESI-TOF-MS and HPLC-DAD-ESI-MS/MS methods. Altogether 37 different phenolic compounds were detected in the extracts: twenty diarylheptanoids (1-20), nine flavonols (21-29) and eight other phenolics: caffeic and quinic acid derivatives and flavanones (30-37). The main compounds of the extracts were identified as myricetin- quercetin- and kaempferol-3-O-rhanmosides.

First characterisation of flavonoid- and diarylheptanoid-type antioxidant phenolics in Corylus maxima by HPLC-DAD-ESI-MS.

Corylus maxima Mill. (Betulaceae) leaves have been used in traditional medicine both internally and externally, nevertheless phytochemical exploration of the plant remains incomplete. In this study, the in vitro antioxidant activity and polyphenolic composition of the ethyl acetate and methanolic extracts of C. maxima leaves and bark are reported for the first time. The radical scavenging activities of the extracts were investigated by the ABTS and DPPH assays. All the extracts of C. maxima possessed notable antioxidant activity. By mean of a HPLC-DAD-ESI-TOF and a HPLC-DAD-ESI-MS/MS method, altogether twenty-two phenolics were tentatively characterised: one flavan derivative (1), seven flavonol derivatives (4, 6, 12, 13, 16, 20 and 21) and fourteen diarylheptanoids (2, 3, 5, 7-11, 14, 15, 17-19 and 22). The amount of the two main flavonoids - myricetin-3-O-rhamnoside (6) and quercetin-3-O-rhamnoside (13) - and two diarylheptanoids - oregonin (3) and hirsutenone (15) - in the extracts were determined by a validated HPLC-ESI-MS/MS method in multiple reaction monitoring (MRM) mode. Our results showed that C. maxima could be considered as a valuable source of pharmacologically important natural products that might contribute to the revaluation of the phytotherapeutical potential of the plant.

Applicability of a blood-brain barrier specific artificial membrane permeability assay at the early stage of natural product-based CNS drug discovery.

While numerous natural products (NPs) possess activity on central nervous system (CNS) targets, there has been no analytical approach to effectively identify compounds with high brain penetration potential in complex mixtures at the early stage of drug discovery. To overcome this issue, the performance of an in vitro parallel artificial membrane permeability assay for the blood-brain barrier (PAMPA-BBB) for natural products and for plant extracts has been validated and characterized. It was found that the PAMPA-BBB assay preserves its predictive power in the case of natural products and provides high phytochemical selectivity, which enables its use as a unique filtering tool in terms of selecting brain-penetrable compounds from plant extracts. Moreover, the present study has demonstrated that simple modifications in the assay design allow the direct use of PAMPA-BBB filtered samples in a dereplication process, as performed by NMR and LC-MS. The applicability of this procedure was demonstrated using extracts prepared from Tanacetum parthenium, Vinca major, Salvia officinalis, and Corydalis cava, representing different types of chemical diversity and complexity. Thus, the proposed protocol represents a potentially valuable strategy in the NP-based CNS drug discovery environment with a high-throughput screening platform.