Antimycobacterial and anti-inflammatory activities of fractions and substances from Erythrina verna Vell focusing on dual severe TB treatment approach.

Tuberculosis remains a major health problem worldwide. Drug-resistant and hypervirulent Mycobacterium tuberculosis (Mtb) strains can lead to a hyperinflammatory response and necrotic pathology in hyper-reactive individuals that require adjunctive treatment. Plant-derived substances have been investigated for TB treatment, among which flavonoids stand out. We evaluate the anti-Mtb, anti-inflammatory and cytotoxicity activities of fractions and substances 1, 2 and 3 isolated from Erythrina verna through a bioassay guided fractionation. Seven fractions (1, 3-5 and 7-9) obtained from dichloromethane E. verna extract inhibited NO production (IC50 ≤ 15 µg/mL) with none or poor cytotoxic effect, while the fractions 4 and 5 notably reduced TNF-a production. Fractions 4, 6 and 9 suppressed Mycobacterium growth with MIC50 ≤ 20 µg/mL. Fraction 4 was the most potent due to dual biological activities. Erythratidinone and alpinumisoflavone inhibited the growth of Mtb H37Rv and hypervirulent strain in bacterial cultures (MIC50 ≤ 20 µg/mL), with erythratidinone standing out in reducing intracellular growth of Mtb H37Rv (5.8 ± 1.1 µg/mL). Alpinumisoflavone and erythratidinone were capable of inhibiting NO and TNF-α production besides showing significant inhibitory effects against Mycobacterium tuberculosis strains with low toxicity in macrophages. Both substances are promising for further studies focusing on an anti-TB dual treatment approach.

Ethyl Acetate Fraction and Isolated Phenolics Derivatives from Mandevilla moricandiana Identified by UHPLC-DAD-ESI-MSn with Pharmacological Potential for the Improvement of Obesity-Induced Endothelial Dysfunction.

Endothelial dysfunction in obesity plays a key role in the development of cardiovascular diseases, and it is characterized by increased vascular tonus and oxidative stress. Thus, this study aimed to investigate the vasodilatory and antioxidant activities of Mandevilla moricandiana ethyl acetate fraction and subfractions. Vascular effects were investigated on aorta isolated from control and monosodium glutamate (MSG) induced-obese Wistar rats, and antioxidant activity was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) methods. The ethyl acetate fraction (MMEAF) induced a concentration-dependent vasodilation on aortic rings through the NO pathway, with the involvement of histamine H1 and estrogen ERα receptors and showed potent antioxidant activity. In aorta of MSG obese rats, maximal relaxation to acetylcholine was increased in the presence of MMEAF (3 µg/mL), indicating that MMEAF ameliorated obesity-induced endothelial dysfunction. Quercetin and kaempferol aglycones and their correspondent glycosides, as well as caffeoylquinic acid derivatives, A-type procyanidin trimer, ursolic and oleanolic triterpenoid acids were identified in subfractions from MMEAF and seem to be the metabolites responsible for the vascular and antioxidant activities of this fraction.

Isolation and characterization of flavonoids from Tapirira guianensis leaves with vasodilatory and myeloperoxidase-inhibitory activities.

The aim of this study was to perform the isolation and characterization of vasodilatory flavonoids from Tapirira guianensis Aubl. (Annacardiaceae) leaves. In this context, ethyl acetate fraction (EA fraction) was obtained and subjected to fractionation batches by HSCCC affording: myricetin 3-O-α-L-rhamnopyranoside (myricitrin, 1); quercetin 3-O-(6"-O-galloyl)-ß-D-galactopyranoside (2); quercetin 3-O-α-L-arabinofuranoside (avicularin, 3); and quercetin 3-O-α-L-rhamnopyranoside (quercitrin, 4). Myricitrin (1) induced a relaxation of 56.07 ± 13.04% at 300 µM (P < 0.05; n = 5), indicating that this flavonoid contributes to the vasodilatory activity of EA fraction. In addition, all EA fraction flavonoids were evaluated for their capacity of inhibiting myeloperoxidase activity and flavonoid (2) (IC50 1.0 ± 0.3 µM) was the strongest peroxidase inhibitor. In conclusion, it was possible to verify that myricitrin together with quercetin are mainly responsible for vasodilatory potential, besides flavonoid 2 for myeloperoxidase inhibition. Together these flavonoids seem to be responsible for Tapirira guianensis cardiovascular effects.

Phenolic compounds from Tocoyena bullata mart (Rubiaceae) with inhibitory activity in mast cells degranulation.

Glycosylated flavonoids, caffeoylquinic acid and 3,5-dicaffeoylquinic acid have been identified in the ethyl acetate partition from the crude ethanol extract of Tocoyena bullata (Rubiaceae) leaves. The fraction containing the mixture of flavonol rutin and a tetraglycosylated flavonoid showed 89.2% inhibition and the mixture of isoquercitrin and 3,5-dicaffeoylquinic acid showed 88.5% inhibition of mast cell degranulation. These results demonstrated that the tetraglycosylated flavonoid, rutin, isoquercitrin and 3,5-dicaffeioylquinic acid were the most promising phenolics for inhibition of mast cell degranulation. For the first time the identification of phenolic constituents and their correlation with inhibitory effect on mast cell degranulation were reported in this work.

Apoptosis Caused by Triterpenes and Phytosterols and Antioxidant Activity of an Enriched Flavonoid Extract from Passiflora mucronata.

BACKGROUND: P. mucronata (Pm) comes from South America, Brazil and is characterized as "Maracujá de Restinga". It is used in folk medicine for its soothing properties and in treating insomnia. OBJECTIVE: The present study for the first time analyzed the antioxidant and cytotoxicity of the hydroalcoholic leaves extract and fractions from Pm. METHOD: The cytotoxicity test will be evaluated by different assays (MTT and CV) against human prostate cancer (PC3) and mouse malignant melanoma (B16F10) cell lines, and the antioxidant test by DPPH method. RESULTS: ß-Amyrin, oleanolic acid, ß-sitosterol and stigmasterol were isolated of the most active, hexane fraction. These substances were tested against the tumor cell lines: ß-sitosterol and stigmasterol showed the most relevant activity to PC3 in CV assay and, oleanolic acid to B16F10 by the MTT assay. In addition, it was possible to indicate that the mode of cell death for stigmasterol, presumably is apoptosis. In terms of antioxidant activity, the hydroalcoholic leaves extract presented higher activity (EC50 133.3 µg/mL) compared to the flower (EC50 152.3 µg/mL) and fruit (EC50 207.9 µg/mL) extracts. By the HPLC-MS, it was possible to identify the presence of flavones in the leaf extract (isoschaftoside, schaftoside, isovitexin, vitexin, isoorientin, orientin). CONCLUSIONS: P. mucronata hexane fraction showed promising cytotoxic effect against cancer cell lines, and stigmasterol contributes to this activity, inducing apoptosis of these cells. Furthermore, as other Passiflora species, Pm extract showed antioxidant activity and flavones are its major phenolic compounds.

Phytochemical Study of Tapirira guianensis Leaves Guided by Vasodilatory and Antioxidant Activities.

The aim of this research was to perform a phytochemical study of the methanol leaves extract of T. guianensis (MET) guided by vasodilatory and antioxidant activities. The chemical profile of MET and the ethyl acetate fraction (EA fraction) was determined by HPLC-UV-MS and EA fraction guided fractionation by reverse-phase chromatography. The vasorelaxant effects of MET, fractions, sub-fractions and constituents were assessed on rat aorta pre-contracted with phenylephrine. Antioxidant activity was evaluated by using a DPPH assay. The results show that MET-induced vasodilation was dependent on NO/cGMP; and that the PI3K/Akt pathway seems to be the main route involved in eNOS activation. The EA fraction showed greater vasodilatory and antioxidant potency and was submitted to further fractionation. This allowed the isolation and characterization of quercetin, quercetin 3-O-(6″-O-galloyl)-ß-d-galactopyranoside and 1,4,6-tri-O-galloyl-ß-d-glucose. Also, galloyl-HHDP-hexoside and myricetin deoxyhexoside were identified by HPLC-UV-MS. These compounds are being described for the first time for T. guianensis. 1,4,6-tri-O-galloyl-ß-d-glucose and quercetin 3-O-(6″-O-galloyl)-ß-d-galactopyranoside showed no vasodilatory activity. Quercetin and myricetin glycoside seems to contribute to the MET activity, since they have been reported as vasodilatory flavonoids. MET-induced vasodilation could contribute to the hypotensive effect of T. guianensis previously reported.

Nitric oxide production, inhibitory, antioxidant and antimycobacterial activities of the fruits extract and flavonoid content of Schinus terebinthifolius

The extract of the fruits from Schinus terebinthifolius Raddi, Anacardiaceae, was obtained by exhaustive extraction with methanol. Its fractions and isolated compounds were collected by fractionation with RP-2 column chromatography. The crude extract, the flavonoid fraction and the isolated compound identified as apigenin (1), were investigated regarding its inhibitory action of nitric oxide production by LPS-stimulated macrophages, antioxidant activity by DPPH and the antimycobacterial activity against Mycobacterium bovis BCG. The samples exhibited a significant inhibitory effect on the nitric oxide production (e.g., 1, IC50 19.23 ± 1.64 µg/ml) and also showed antioxidant activity. In addition, S. terebinthifolius samples inhibited the mycobacterial growth ( e.g., 1, IC50 14.53 ± 1.25 µg/ml). The necessary concentration to produce 50% of the maximum response (IC50) of these activities did not elicit a significant cytotoxic effect when compared with the positive control (100% of lysis). The antioxidant and nitric oxide inhibition activity displayed by S. terebinthifolius corroborates its ethnopharmacological use of this specie as an anti-inflammatory. In addition, our results suggest that the flavonoids of S. terebinthifolius are responsible for the activities found. We, describe for the first time the activity against Mycobacterium bovis BCG and the inhibition of nitric oxide production for S. terebinthifolius.

Flavonoids in the therapy and prophylaxis of flu: a patent review.

INTRODUCTION: Influenza viruses are common agents of flu outbreaks, epidemics, and pandemics that have occurred through the centuries. Prevention and control of flu are of great clinical importance, since they cause serious damage to health, with a consequent impact on quality of life and economy of a country. Resistance against the current drugs justifies the development of new anti-influenza molecules. Flavonoids exhibit significant activity against flu through their anti-inflammatory and antiviral properties. The profile of these molecules makes them particularly promising as therapeutic agents against flu. AREAS COVERED: This review focus on the activity of flavonoids on different influenza virus targets as well as their use in patented pharmaceutical formulations. Twenty-one patents of these compounds for prophylaxis and treatment of influenza infection are discussed. EXPERT OPINION: The H1N1 influenza pandemic in 2009 resulted in a significant increase in the number of patents claiming pharmaceutical formulations for prophylaxis and treatment of flu. The research advances on flavonoids showing anti-influenza activity and the efforts made by researchers and industries consolidate the interest on new alternatives for the therapy of an infectious disease that represents a serious public health problem throughout the world.

Flowers from Kalanchoe pinnata are a rich source of T cell-suppressive flavonoids.

The chemical composition and immunosuppressive potential of the flowers from Kalanchoe pinnata (Crassulaceae) were investigated. We found that the aqueous flower extract was more active than the leaf extract in inhibiting murine T cell mitogenesis in vitro. Flavonoids isolated from the flower extract were identified and quantitated based on NMR and HPLC-DAD-MS analysis, respectively. Along with quercetin, four quercetin glycosyl conjugates were obtained, including quercetin 3-O-beta-D-glucuronopyranoside and quercetin 3-O-beta-D-glucopyranoside, which are described for the first time in K. pinnata. All flavonoids inhibited murine T cell mitogenesis and IL-2 and IL-4 production without cell toxicity. This is the first report on the pharmacological activity of flowers of a Kalanchoe species, which are not used for curative purposes. Our findings show that K. pinnata flowers are a rich source of T-suppressive flavonoids that may be therapeutically useful against inflammatory diseases.

Influence of cultivation conditions, season of collection and extraction method on the content of antileishmanial flavonoids from Kalanchoe pinnata.

ETHNOPHARMACOLOGICAL RELEVANCE: Leaves from Kalanchoe pinnata (Lamarck) Persoon (Crassulaceae) are popularly used for healing wounds. Its antileishmanial properties are established in experimental animals, and its active flavonoid components have been identified. AIM OF THE STUDY: In this study, we attempted to standardize the extract from K. pinnata leaves by evaluating the influence of season of harvest, sunlight exposure and method of extraction on antileishmanial flavonoids content. MATERIALS AND METHODS: HPLC-DAD-MS was used to identify and quantify the active antileishmanial flavonoids in different extracts. ANOVA test for analyses of variance followed by the Tukey test of multiple comparisons were used in the statistical analysis. The antileishmanial potential was assessed by the activation of nitric oxide production by murine macrophage using the Griess method. RESULTS: We demonstrated that active flavonoids were significantly more abundant when the leaves were collected in the summer, and that aqueous extraction at 50°C allowed the highest flavonoid extraction. The benefit of sunlight exposure was confirmed in plants cultivated under direct sunlight when compared with those that grown under shade. Under sunny conditions the yield of the most active antileishmanial favonoid quercitrin was increased by 7-fold. All aqueous extracts tested were capable to enhance the macrophage nitric oxide production. However, hot aqueous extract from leaves collected in summer exhibited the higher activity, in agreement with HPLC-DAD-MS analysis tendency. In addition, with the aim of reducing the individual chemical variations of the plant constituents and optimizing the production of the active extract, it was obtained in vitro monoclonal KP specimens that were easily adapted to field conditions and were able to produce antileishmanial flavonoids. CONCLUSION: Our study reports the better conditions of cultivation, harvest and extraction protocol for obtaining a K. pinnata extract exhibiting the highest antileishmanial activity. Additionally, we propose the flavonoids quercetin 3-O-α-L-arabinopyranosyl (1→2)-α-L-rhamnopyranoside and quercitrin, as satisfactory chemical markers for standardization purposes.

Oral metabolism and efficacy of Kalanchoe pinnata flavonoids in a murine model of cutaneous leishmaniasis.

Leishmaniasis is a parasitic disease that threatens 350 million people worldwide. In a search for new antileishmanial drugs, the in vitro activity of flavonoids from Kalanchoe pinnata (Crassulaceae) was previously demonstrated in infected cells. In order to demonstrate the safety and oral activity of K. pinnata, flavonoids were evaluated in vivo in a murine model of cutaneous leishmaniasis. Daily oral doses of quercetin 3-O-alpha-L-arabinopyranosyl (1-->2)-alpha-L-rhamnopyranoside, quercetin 3-O-alpha-L-rhamnopyranoside, and free quercetin (16 mg/kg body weight) all were able to control the lesion growth caused by Leishmania amazonensis and to significantly reduce parasite load. These flavonoids were as effective as the crude K. pinnata aqueous extract given at 320 mg/kg body weight. HPLC-DAD-MS analysis of the plasma of extract-treated mice suggested that quercetin and quercetin glucuronides are the main metabolites of K. pinnata quercetin glycosides. Our results indicate that K. pinnata quercetin glycosides are important active components of the aqueous extract and that they possess potent oral efficacy against cutaneous leishmaniasis.

1-octen-3-O-alpha-L-arabinopyranosyl-(1 -> 6)-beta-glucopyranoside, a minor substance from the leaves of Kalanchoe pinnata (Crassulaceae)

From the leaves of Kalanchoe pinnata (Crassulaceae), a medicinal plant widely used against inflammatory processes which exhibit a important immunosuppressive and anti-leishmanial activities, was isolated a minor vinylic aliphatic alcohol diglycoside which structure was proposed as the known 1-octen-3-O-alpha-L-arabinopyranosyl-(1 -> 6)-beta-glucopyranoside based on ¹H and 13C mono and bi-dimensional NMR experiments and GC-MS analysis, after successive chromatographic column procedures. This molecule is a water-soluble derivative of the volatile aglicone 1-octen-3-ol that appears to be attractant of pollinators and signalling of defence against herbivores.

A partir das folhas de Kalanchoe pinnata (Crassulaceae), uma planta medicinal amplamente utilizada contra processos inflamatórios e que apresenta importante atividade imunossupressora e anti-leishmania, foi isolado um álcool vinílico diglicosilado minoritário, caracterizado como 1-octeno-3-O-alfa-L-arabinopiranosil-(1 -> 6)-beta-glicopiranosídeo baseado em RMN mono e bi-dimensional e em CG-EM, após sucessivos processos cromatográficos em coluna. Esta molécula é um derivado hidrossolúvel da aglicona 1-octen-3-ol, molécula que atua como atrativo para polinizadores e sinalizador de defesa contra herbivoria.

The antileishmanial activity assessment of unusual flavonoids from Kalanchoe pinnata.

The importance of flavonoids for the antileishmanial activity of Kalanchoe pinnata was previously demonstrated by the isolation of quercitrin, a potent antileishmanial flavonoid. In the present study, the aqueous leaf extract from the medicinal plant K. pinnata (Crassulaceae) afforded a kaempferol di-glycoside, named kapinnatoside, identified as kaempferol 3-O-alpha-L-arabinopyranosyl (1-->2) alpha-L-rhamnopyranoside (1). In addition, two unusual flavonol and flavone glycosides already reported, quercetin 3-O-alpha-L-arabinopyranosyl (1-->2) alpha-L-rhamnopyranoside (2) and 4',5-dihydroxy-3',8-dimethoxyflavone 7-O-beta-D-glucopyranoside (3), have been isolated. Their structures were determined via analyses of mono and bi-dimensional (1)H and (13)C NMR spectroscopic experiments and HR-MALDI mass spectra. Because of its restricted occurrence and its abundance in K. pinnata, flavonoid (2) may be a chemical marker for this plant species of high therapeutic potential. The three flavonoids were tested separately against Leishmania amazonenis amastigotes in comparison with quercitrin, quercetin and afzelin. The quercetin aglycone - type structure, as well as a rhamnosyl unit linked at C-3, seem to be important for antileishmanial activity.

Quercitrin: an antileishmanial flavonoid glycoside from Kalanchoe pinnata.

Quercitrin (quercetin 3- O-alpha- L-rhamnopyranoside), one of the constituents of the biologically active aqueous extract obtained from Kalanchoe pinnata, is demonstrated to be a potent antileishmanial compound (IC50 approximately 1 microg/mL) with a low toxicity profile. This is the first time that antileishmanial activity is demonstrated for a flavonoid glycoside.

Phytochemical and pharmacological study of Sedum dendroideum leaf juice.

The fresh juice from leaves of Sedum dendroideum Moc & Sessé (Crassulaceae) is used in Brazilian traditional medicine for the treatment of gastric and inflammatory disorders. The present investigation was carried out to evaluate in vivo antinociceptive and anti-inflammatory activities of this plant material. The oral administration (0.1-1g/kg) of the lyophilized Sedum dendroideum juice (L J) caused a significant dose-related reduction of acetic acid-induced writhing response (ID(50)=631 mg/kg) and inhibited croton oil-induced ear oedema formation (66% inhibition at 1g/kg) in mice. In the formalin-induced nociception in mice, L J (1g/kg) only inhibited the second phase of nociception (46%). Phytochemical investigation revealed four known kaempferol glycosides, here, described at the first time for this species. These flavonoids probably explain the antinociceptive and anti-inflammatory effects of the fresh juice of Sedum dendroideum.

C-glycosylflavones from the aerial parts of Eleusine indica inhibit LPS-induced mouse lung inflammation.

The infusion of aerial parts (EI) of Eleusine indica Gaertn (Poaceae) is used in Brazil against airway inflammatory processes like influenza and pneumonia. Pre-treatment with 400 mg/kg of crude extract inhibited 98% of lung neutrophil recruitment in mice exposed to aerosols of lipopolysaccharide (LPS) from Gram-negative bacteria, in a dose-dependent manner. At 400 microg/kg, schaftoside (6-C-beta-glucopyranosyl-8-C-alpha-arabinopyranosylapigenin) and vitexin (8-C-beta-glucopyranosylapigenin), isolated from EI, inhibited 62% and 80% of lung neutrophil influx, respectively. These results may justify the popular use of E. indica against airway inflammatory processes.