Taxifolin stability: In silico prediction and in vitro degradation with HPLC-UV/UPLC-ESI-MS monitoring.

Taxifolin has a plethora of therapeutic activities and is currently isolated from the stem bark of the tree Larix gmelinni (Dahurian larch). It is a flavonoid of high commercial interest for its use in supplements or in antioxidant-rich functional foods. However, its poor stability and low bioavailability hinder the use of flavonoid in nutritional or pharmaceutical formulations. In this work, taxifolin isolated from the seeds of Mimusops balata, was evaluated by in silico stability prediction studies and in vitro forced degradation studies (acid and alkaline hydrolysis, oxidation, visible/UV radiation, dry/humid heating) monitored by high performance liquid chromatography with ultraviolet detection (HPLC-UV) and ultrahigh performance liquid chromatography-electrospray ionization-mass spectrometry (UPLC-ESI-MS). The in silico stability prediction studies indicated the most susceptible regions in the molecule to nucleophilic and electrophilic attacks, as well as the sites susceptible to oxidation. The in vitro forced degradation tests were in agreement with the in silico stability prediction, indicating that taxifolin is extremely unstable (class 1) under alkaline hydrolysis. In addition, taxifolin thermal degradation was increased by humidity. On the other hand, with respect to photosensitivity, taxifolin can be classified as class 4 (stable). Moreover, the alkaline degradation products were characterized by UPLC-ESI-MS/MS as dimers of taxifolin. These results enabled an understanding of the intrinsic lability of taxifolin, contributing to the development of stability-indicating methods, and of appropriate drug release systems, with the aims of preserving its stability and improving its bioavailability.

Plumieride exerts anxiolytic-like effect mediated by GABAergic and monoaminergic systems.

Plumieride (PLU), an iridoid isolated from Allamanda cathartica flowers, has been studied by our research group due to its anti-inflammatory potential, antidepressant-like and anxiolytic-like effects. This research investigated the involvement of GABAergic and monoaminergic systems in the anxiolytic-like effect elicited by PLU. Therefore, mice were pre-treated with GABAergic, serotonergic, adrenergic or dopaminergic receptor antagonists (i.p.), and exposed to Elevated Plus-Maze (EPM) and Open-Field Test (OFT). The preliminary results revealed that PLU (p.o.) possibly interacts with the mentioned systems through the GABAA, GABAB, 5-HT1A, 5-HT3, α1, α2, and D2 receptors.

Taxifolin stability:In silico prediction and in vitro degradation with HPLC-UV/UPLC-ESI-MS monitoring / 药物分析学报

Taxifolin has a plethora of therapeutic activities and is currently isolated from the stem bark of the tree Larix gmelinni(Dahurian larch).It is a flavonoid of high commercial interest for its use in supplements or in antioxidant-rich functional foods.However,its poor stability and low bioavailability hinder the use of flavonoid in nutritional or pharmaceutical formulations.In this work,taxifolin isolated from the seeds of Mimusops balata,was evaluated by in silico stability prediction studies and in vitro forced degradation studies(acid and alkaline hydrolysis,oxidation,visible/UV radiation,dry/humid heating)monitored by high performance liquid chromatography with ultraviolet detection(HPLC-UV)and ultrahigh perfor-mance liquid chromatography-electrospray ionization-mass spectrometry(UPLC-ESI-MS).The in silico stability prediction studies indicated the most susceptible regions in the molecule to nucleophilic and electrophilic attacks,as well as the sites susceptible to oxidation.The in vitro forced degradation tests were in agreement with the in silico stability prediction,indicating that taxifolin is extremely unstable(class 1)under alkaline hydrolysis.In addition,taxifolin thermal degradation was increased by humidity.On the other hand,with respect to photosensitivity,taxifolin can be classified as class 4(stable).Moreover,the alkaline degradation products were characterized by UPLC-ESI-MS/MS as dimers of taxifolin.These results enabled an understanding of the intrinsic lability of taxifolin,contributing to the development of stability-indicating methods,and of appropriate drug release systems,with the aims of preserving its stability and improving its bioavailability.

RP-HPLC and LC-MS-MS determination of a bioactive artefact from Ipomoea pes-caprae extract

Abstract Solvents play important and critical role in natural product chemistry and could generate artefacts during the extraction and purification of metabolites from a biological matrix. This study aimed to correlate the chromatographic profile with biological activity of Ipomoea pes-caprae (L.) R. Br., Convolvulaceae, extracts obtained with hydroethanolic extraction. Thus, aerial parts of I. pes-caprae were extracted with different concentration of ethanol (50, 70 and 90°GL) and the obtained extracts were analysed by HPLC-UV. HPLC data were studied employing chemometrics to discriminate the samples. Moreover these samples were further characterized by using UPLC-QTOF/MS data. The extracts were also biomonitored through the paw-oedema and spontaneous nociception induced by trypsin in mice. Different chromatographic profiles were obtained and the exploratory analysis clearly revealed higher level of ethyl caffeate in extracts of lower strength of ethanol (50°GL). This compound was suggested to be an artefact formed by transesterification of caffeoylquinic acid derivatives present in the plant, once it was not observed when other solvents were employed. During the biological assay, only the extract obtained with ethanol 50°GL presented significant inhibition of inflammation (45 ± 9%) and nociception (24 ± 3%). Ethyl caffeate seems to be linked to the anti-inflammatory effect since it reduced 86 ± 5% of paw-oedema induced by trypsin. Artefacts could contribute to the biological activity of herbal preparations and consequently lead to misinterpretation of the results.

New pharmacological insights of Galactia glaucescens.

Galactia glaucescens leaves are popularly used against snakebites in Brazil. The hydroethanolic extract from aerial parts of G. glaucescens (HEGg) was assayed against the neurotoxicity and myotoxicity induced by Bothrops jararacussu venom. A traditional myographic technique was applied for neurotoxicity and the resulting muscles were treated routinely by light microscopy analysis for myotoxicity. Additionally, the antimicrobial potential of HEGg was evaluated against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa strains, as well as Rutin was isolated for the first time in this specie using chromatographic and spectroscopic methods and its antiophidian property was assessed. HEGg totally prevents the neurotoxicity and myotoxicity effects caused by B. jararacussu, but did not show any antimicrobial effect. Concluding, HEGg and Rutin were able to counteract the toxic effects of the venom and confirmed the antiophidian potential, but not antimicrobial, of G. glaucescens as an alternative for neutralization of B. jararacussu venom.

Antioxidant and anti-inflammatory effect of plumieride in dextran sulfate sodium-induced colitis in mice.

This study aimed to investigate the potential effect of plumieride, an iridoid glycoside isolated from Alamanda cathartica L. flowers, against dextran sulfate sodium (DSS)-induced colitis in mice. Colitis was induced in female swiss mice by adding DSS 3% to the drinking water. The animals were treated with vehicle (water), 5-aminosalicylic acid (100?mg/kg) or plumieride (10, 30 and 100?mg/kg) once a day, during 7 days. The body weight progression and the disease activity index was evaluated daily. On the eighth day, colons were collected for the measurement of the size, histological, histochemical, biochemical and inflammatory analysis. The cytotoxicity of plumieride on intestinal epithelial cell (IEC-6 cell line) was also evaluated. Plumieride, at dose of 100?mg/kg, significantly attenuated the mice weight loss, showed lower score in the disease activity index, diminished the colon shortening, improved the histological damage and avoided mucosa intestinal mucus depletion when compared with vehicle-treated only group. Moreover, plumieride was able to reduce the amount of colonic lipid hydroperoxides, while augmented reduced glutathione levels and superoxide dismutase activity. Although DSS intake stimulated an increase in myeloperoxidase activity and in tumor necrosis factor content on the colon tissue of the vehicle-treated group, the colons obtained from mice treated with plumieride did not present any of these changes. Taking together, the results of the present study disclose that plumieride exhibited a significant efficacy in attenuating the parameters of experimental ulcerative colitis, which may be mediated by an antioxidant and anti-inflammatory effect.

Neuropharmacological and acute toxicological evaluation of ethanolic extract of Allamanda cathartica L. flowers and plumieride.

Psychiatric diseases affect more than 350 million people all over the world, and medicinal plants have been considered the basis for pharmacological research. The study investigates the anticonvulsant and antidepressant-like activities and acute toxicological effects of ethanolic extract of Allamanda cathartica flowers, and plumieride. The extract was analyzed by HPLC and plumieride was isolated. Toxicity studies were carried out on females Wistar rats (2000 mg/kg). Toxicity was evaluated by measuring biochemical parameters and conducting histopathological analysis. For pharmacological evaluation different doses of the extract (100, 150 and 300 mg/kg, p.o.) and plumieride (0.5, 1 and 2 µg/kg, i.p.) were administered before the Forced-Swimming Test (FST), pentylenetetrazole seizure test (PTZT) or Tail-Suspension Test (TST) in mice. Furthermore, hemolytic activity, cytotoxicity and micronucleus test were performed. In addition, mutagenicity and reproductive/developmental toxicity were estimated by TEST-software analysis. Data show that both treatments induce significant antidepressive-like effect in FST and TST, but not anticonvulsant effect. The effect of plumieride last up to 4 h after treatment. No signs of toxicity, mutagenicity, cytotoxicity or hemolytic activity were observed. The TEST-software demonstrated that plumieride present reproductive/developmental toxicity. Together, the data obtained show that the flowers extract and plumieride present antidepressant-like effect and did not present signals of acute toxicity.

Biomonitored UHPLC-ESI-QTOF-MS2 and HPLC-UV thermostability study of the aerial parts of Sphagneticola trilobata (L.) Pruski, Asteraceae.

As the temperature of extraction and processing could impact the biological effects of herbal extracts, which have wide chemical diversity, the aim of this work were to investigate the thermostability of herbal derivatives of the aerial parts of Sphagneticola trilobata, a reputed medicinal plant; to biomonitor its oral anti-hyperalgesic effect; and to elucidate the degradation pathways of the major components by UHPLC-ESI-QTOF-MS. The lipophilic markers (kaurenoic acid-KA) and hydrophilic markers [chlorogenic acids; measured as total phenolic compounds (PC), expressed in caffeic acid] were also monitored through a validated HPLC-UV methodology, suitable for quality control and stability studies. The soft extract (drug:solvent ratio of 1:10, ethanol 60% v/v) was exposed to high temperatures (50-180°C). PC showed high thermolability (27.4% of degradation at 150°C), compared to KA (16.5%, at 180°C). These results suggest that the loss of oral anti-hyperalgesic activity observed in the spray-dried extracts (dried at 170°C), compared with the soft and the lyophilized extract may be related to degradation of the active components, especially the polar compounds, i.e. chlorogenic acid derivatives and the four oleanane type triterpenoid saponins. These latter degraded at temperatures above 150°C and vanished at 180°C, as demonstrated in the UHPLC-ESI-QTOF-MS analyses. These results provide a relevant guide for the extraction process of S. trilobata, aimed at preserving the antinociceptive effect.

A Highly Polar Phytocomplex Involving Rutin is Responsible for the Neuromuscular Facilitation Caused by Casearia sylvestris (guaçatonga).

BACKGROUND: Of the various biological activities ascribed to extracts from Casearia sylvestris (guaçatonga), its facilitatory activity, i.e., ability to increase skeletal muscle contractile amplitude, has promising therapeutic applications. In this work, we investigated the components responsible for the previously described neurofacilitation caused by C. sylvestris leaves. METHODS: The methanolic fraction of C. sylvestris leaves was initially fractionated by column chromatography and partitioned in a MeOH:H2O gradient. The resulting fractions were analyzed by analytical HPLC and yielded fraction 5:5 (F55) that was subjected to solid phase extraction and preparative HPLC. Of the seven resulting subfractions, only F55-6 caused muscle facilitation. Subfractions F55-6 and F55-7 (similar in composition to F55-6 by TLC analysis, but inactive) were analyzed by 1H-NMR to identify their constituents. RESULTS: This analysis identified a rutin-glycoside phytocomplex that caused neurofacilitation, a property that commercial rutin alone did not exhibit. CONCLUSION: F55-6 apparently caused neurofacilitation by the same mechanism (presynaptic action) as the methanolic fraction since its activity was also inhibited in tetrodotoxin-pretreated preparations.

Gastroprotective xanthones isolated from Garcinia achachairu: Study on mucosal defensive factors and H(+), K(+)-ATPase activity.

The present study was designed to investigate the gastroprotective effect of xanthones 7-preniljacareubin (PJB), 1,3,5,6-tetrahydroxy xanthone (THX), 3-demethyl-2-geranyl-4-prenylbellidypholine (DGP) and 1,5,8-trihydroxy-4', 5'-dimethyl-2H-pyrane (2,3:3,2)-4-(3-methylbut-2-enyl) xanthone (TDP) isolated of branches from G. achachairu. Their structures were identified through the spectroscopic analysis in comparison with previously reported data. The xanthones were tested at dose of 10 mg/kg against ethanol 60%/HCl 0.3 N-induced gastric ulcer in female swiss mice. The xanthones PJB, THX, DGP and TDP exhibit gastroprotective effect after intraperitoneal treatment, but only the first two displayed anti-ulcer activity after oral administration. Both PJB and THX augmented the antioxidative capacity of tissue by an increase in glutathione levels, as well as were able to prevent an increase in myeloperoxidase activity and tumor necrosis factor level. On the other hand, only THX showed an in vitro free radical scavenger activity, and only PJB avoided mucus depletion on gastric mucosa, which was not associated with an increase in mucin production at glandular level. In addition, PJB and THX inhibited the in vitro H(+)K(+)-ATPase activity at similar range as omeprazole. Together, these results demonstrate the anti-ulcer efficacy of xanthones isolated from G. achachairu, which can contribute for future directions in the development of effective strategies to improve gastric diseases.