Giany O. De Melo

Antinociceptive and anti-inflammatory kaempferol glycosides from Sedum dendroideum.

AIM OF THE STUDY To identify the compounds responsible for the antinociceptive and anti-inflammatory effects previously described for Sedum dendroideum, through bioassay-guided fractionation procedures. MATERIALS AND METHODS Antinociceptive activity was evaluated through mouse acetic acid-induced writhing model. The anti-inflammatory activity was assessed through croton oil-induced mouse ear oedema and carrageenan-induced peritonitis. RESULTS The Sedum dendroideum juice afforded seven known flavonoids identified with basis on NMR data. The oral administration of the major kaempferol glycosides kaempferitrin [1] (17.29 micromol/kg), kaempferol 3-O-beta-glucopyranoside-7-O-alpha-rhamnopyranoside [2] (16.82 micromol/kg), kaempferol 3-O-neohesperidoside-7-O-alpha-rhamnopyranoside [3] (13.50 micromol/kg) or alpha-rhamnoisorobin [5] (23.13 micromol/kg) inhibited by 47.3%, 25.7%, 60.2% and 58.0%, respectively, the acetic acid-induced nociception (indomethacin: 27.95 micromol/kg, p.o.; 68.9%). Flavonoids 1, 2, 3 or 5, at the same doses, reduced by 39.5%, 46.5%, 35.6% and 33.3%, respectively, the croton oil-induced oedema (dexamethasone: 5.09 micromol/kg, s.c.; 83.7%) and impaired leukocyte migration by 42.9%, 46.3%, 50.4% and 49.6%, respectively (dexamethasone: 5.09 micromol/kg, s.c.; 66.1%). CONCLUSIONS Our findings show that the major kaempferol glycosides may account for the renowned medicinal use of Sedum dendroideum against pain and inflammatory troubles.

Substâncias de origem vegetal potencialmente úteis na terapia da asma

Asthma is a chronic inflammatory disease, which represents a huge public health problem in developed and developing countries, has high death rates and elevated socioeconomic implications. The pathology is characterized by two different phases: the initial stage, mediated by acute inflammatory cell response and the late phase, responsible for specific immune cells. Currently, the main drugs used for asthma treatment are bronchodilator and anti-inflammatory agents, which mechanisms focus the relief of symptoms and attenuation of airway inflammation. However, therapies with those drugs have side effects besides they are not totally effective. Poor accessibility in the development countries and scarcity of safety drugs lead the search for new drugs to asthma treatment. Herbal natural products have elevated pharmacological potential against asthma, once they provide several molecules with specific mechanisms for the pathology control and treatment. Thus, search in herbal natural products plays an important role to find out specific and effective mechanisms.

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.

Kalanchosine Dimalate, an Anti-inflammatory Salt from Kalanchoe brasiliensis

This report describes the isolation and characterization of kalanchosine dimalate (KMC), an anti-inflammatory salt from the fresh juice of the aerial parts of Kalanchoe brasiliensis. KMC comprises the new metabolite kalanchosine (1) and malic acid (2) in a 1:2 stoichiometric ratio. Kalanchosine (1), 3,6-diamino-4,5-dihydroxyoctanedioic acid, is the first naturally occurring dimeric bis(gamma-hydroxy-beta-amino acid) and is at least partially responsible for the anti-inflammatory properties of K. brasiliensis.

Antidiabetic activity of Sedum dendroideum: Metabolic enzymes as putative targets for the bioactive flavonoid kaempferitrin

The aim of this study was to evaluate the antidiabetic potential of a leaf extract and flavonoids from Sedum dendroideum (SD). Additionally, our goals were to establish a possible structure/activity relationship between these flavonoids and to assess the most active flavonoid on the glycolytic enzyme 6‐phosphofructo‐1‐kinase (PFK). SD juice (LJ), a flavonoid‐rich fraction (BF), and separately five flavonoids were evaluated intraperitoneally for their acute hypoglycemic activity in normal and streptozotocin‐induced diabetic mice. First, the major flavonoids kaempferol 3,7‐dirhamnoside or kaempferitrin (1), kaempferol 3‐glucoside‐7‐rhamnoside (2), and kaempferol 3‐neohesperidoside‐7‐rhamnoside (3) were tested. Then, the monoglycosides kaempferol 7‐rhamnoside (5) and kaempferol 3‐rhamnoside (6) were assayed to establish their structure/activity relationship. The effect of 1 on PFK was evaluated in skeletal muscle, liver, and adipose tissue from treated mice. LJ (400 mg/kg), BF (40 mg/kg), and flavonoid 1 (4 mg/kg) reduced glycemia in diabetic mice (120 min) by 52, 53, and 61%, respectively. Flavonoids 2, 3, 5, and 6 were inactive or showed little activity, suggesting that the two rhamnosyl moieties in kaempferitrin are important requirements. Kaempferitrin enhanced the PFK activity chiefly in hepatic tissue, suggesting that it is able to stimulate tissue glucose utilization. This result is confirmed testing kaempferitrin on C2C12 cell line, where it enhanced glucose consumption, lactate production, and the key regulatory glycolytic enzymes. The hypoglycemic activity of kaempferitrin depends on the presence of both rhamnosyl residues in the flavonoid structure when intraperitoneally administered. Our findings show for the first time that a flavonoid is capable of stimulating PFK in a model of diabetes and that kaempferitrin stimulates glucose‐metabolizing enzymes. This study contributes to the knowledge of the mechanisms by which this flavonoid exerts its hypoglycemic activity.

Inhibition of B cell development by kalanchosine dimalate

Kalanchoe brasiliensis (Kb) is a medicinal plant from the Crassulaceae family, used in folk medicine to treat inflammatory and infectious diseases. Here we show that short-term treatment of mice with a highly purified compound named kalanchosine dimalate (KMC), obtained from Kb, led to a strong and selective inhibition of B cell development in the bone marrow, without affecting the myeloid lineage development. Numbers of mature B lymphocytes in bone marrow or peripheral lymphoid organs were preserved in KMC treated mice. The inhibitory effect of KMC was acute and rapidly reverted with the interruption of the treatment. In vitro, KMC, inhibited the interleukin-7 dependent proliferation of B cell precursors and do not induce cell death. Also in vitro, the maturation of B cell precursors was not affected by KMC. KMC does not inhibit the proliferative response to IL-3 or IL-2. These results suggest that KMC is selectively affecting B cell lymphopoiesis, possibly acting on the IL-7 signaling pathway, opening new perspectives for a potential therapeutic usage of Kb derived drugs.

Selective blockade of lymphopoiesis induced by kalanchosine dimalate: inhibition of IL-7-dependent proliferation

Lymphopoiesis and myelopoiesis continuously generate mature cells from hematopoietic cell progenitors during the lifetime of the organism. The identification of new endogenous or exogenous substances that can act specifically on the differentiation of distinct cell lineages is of relevance and has potential therapeutical use. Kalanchoe brasiliensis (Kb) is a medicinal plant from the Crassulaceae family, used in folk medicine to treat inflammatory and infectious diseases. Here, we show that short‐term treatment of naïve mice with Kb led to a strong and selective inhibition of lymphopoiesis, affecting B and T cell lineages without reduction of the myeloid lineage development. Similar effects were observed after treatment with the highly purified compound kalanchosine dimalate (KMC), obtained from Kb. Numbers of mature lymphocytes in secondary lymphoid organs were preserved in Kb(KMC)‐treated mice. The effect of Kb(KMC) was not a result of secondary augmentation of plasma levels of endogenous corticoids; neither involves TNF‐α, type‐I IFN, or TLR2/TLR4 ligands, which have all been described as selective inhibitors of lymphopoiesis. Flow cytometry analysis of the phenotypes of T and B cell precursors indicate a blockade of maturation on IL‐7‐dependent, proliferative stages. In vitro, Kb(KMC) inhibited the IL‐7‐dependent proliferation of pre‐B cells and does not induce massive apoptosis of B and T cell precursors. These results suggest that Kb(KMC) is selectively blocking lymphopoiesis through a mechanism that does not involve the previously characterized substances, possibly acting on the IL‐7 signaling pathway, opening new perspectives for a potential therapeutic use of Kb‐derived drugs.