Maria Raquel Figueiredo

Antimicrobial activity in vitro of plumbagin isolated from Plumbago species

Plumbagin is a naturally occurring naphthoquinone isolated from roots of Plumbago scandens. The plant was collected at the Campus of Fundação Oswaldo Cruz, Rio de Janeiro, Brazil. P. scandens is used as a traditional medicine for the treatment of several diseases. The antimicrobial activity of plumbagin was evaluated using the macrodilution method. The compound exhibited relatively specific activity against bacteria and yeast. The minimum inhibitory concentration test showed the growth inhibiton of Staphylococcus aureus at a concentration of 1.56 g/ml and of Candida albicans at a concentration of 0.78 g/ml. These results suggest the naphthoquinone plumbagin as a promising antimicrobial agent.

The anti-allergic activity of the acetate fraction of Schinus terebinthifolius leaves in IgE induced mice paw edema and pleurisy

Schinus is a genus of the Anacardiaceae family and contains Schinus terebinthifolius, the Brazilian pepper tree that is widely used in folk medicine. We investigate the anti-allergic activity of the ethyl acetate fraction of S. terebinthifolius Raddi (ST fraction). HPLC analysis reveled that gallic acid, methyl gallate and 1,2,3,4,6-pentagalloylglucose are the major aromatic components of the fraction. Oral pre-treatment with the ST fraction (100 mg/kg) significantly inhibited paw edema induced by compound 48/80 (100 ng/paw) and to a lesser extent, the allergic paw edema (OVA, 3 microg/paw). The ST fraction (100 and 200 mg/kg) also inhibited the edema induced by histamine (100 microg/paw), preventing mast cell degranulation and, consequently, histamine release in Wistar rat peritoneal mast cells induced by C 48/80 (5 microg/mL). This histamine inhibition was also observed after mast cell pre-treatment with both methyl gallate and 1,2,3,4,6-pentagalloylglucose (100 microg/mL), the isolated compounds from the ethyl acetate fraction. Pre-treatment with the ST fraction (100 mg/kg) significantly inhibited total leukocyte and eosinophil accumulation in pleural cavities 24 h after the intrathoracic injection of OVA (12.5 microg/cavity). This effect was related to the inhibition of CCL11/eotaxin and CCL5/RANTES in pleural lavage fluid. Pre-treatment with this fraction (100 mg/kg) failed to reduce the cell influx that was observed after LPS-injection into pleural cavity (250 ng/cavity). These findings demonstrate the anti-allergic effect of the ST fraction, which includes the inhibition of edema formation and histamine release caused by mast cell degranulation and eosinophil influx into the pleural cavity probably reflected by the decreased levels of chemokines in recovered pleural lavage fluid.

Isolation of limonoids from seeds of Carapa guianensis Aublet (Meliaceae) by high-speed countercurrent chromatography.

INTRODUCTION Limonoids are tetranortriterpenoids of considerable interest due to their structural varieties and biological activities, such as insecticidal, antibacterial, antifungal, antimalarial, anticancer and antiviral. They contain oxygen atoms that confer a moderate polarity and are responsible for the difficulties in their separation by traditional chromatographic methods. High-speed countercurrent chromatography (HSCCC) is a versatile liquid-liquid separation technique, in which the sample is distributed between two non-miscible phases to achieve separation. OBJECTIVE To isolate limonoids from a complex Carapa guianensis seed extract by gradient elution HSCCC and to identify them by spectrometric and spectroscopic methods. METHODOLOGY The hexane extract of Carapa guianensis squeezed seeds was prepared by Soxhlet extraction. From this extract, 800 mg were submitted to gradient mode HSCCC, using the solvent systems hexane:ethyl acetate:methanol:water 1:2:X:1, X = 1.5 (system A) and X = 1.75 (system B). The upper organic phase of the system A was used as stationary phase, and the lower aqueous phases of both systems as mobile phases. In this procedure, 165 fractions of 4 mL (660 mL) were collected. RESULTS Six compounds were isolated. Spectrometric and spectroscopic analysis allowed the identification of the substances, as follows: methyl angolensate (28.7 mg), 7-deacetoxy-7-oxogedunin (17.9 mg), deacetylgedunin (3.7 mg), 6alpha-acetoxygedunin (40.1 mg), gedunin (21.0 mg), and andirobin (5.8 mg). CONCLUSION The use of gradient mode in HSCCC was a good alternative, exploiting small variations of partition coefficient between the substances. Thus it was possible to isolate them in a good relative abundance, compared with classical chromatographic methods.

Plumbagin quantification in roots of Plumbago scandens L. obtained by different extraction techniques

The Plumbago genus belongs to the Plumbaginaceae family and it is known due to its variety of biological uses, most of them attributed to the presence of naphthoquinones. Plumbagin is a naturally occurring naphthoquinone that can be obtained from roots of Plumbago scandens L. In order to find out the better technique for plumbagin extraction, were applied: static maceration, dynamic maceration, with assistance of ultrasonic waves and in Soxhlet apparatus. Four compounds were qualitatively detected in all extracts: the naphthoquinones plumbagin and epi-isoshinanolone, palmitic acid and sitosterol. Plumbagin was always the major component in all analyzed extracts and it was quantitatively determined by gas chromatograph coupled with mass spectrometer. Soxhlet was the most efficient extraction technique however, prolonged heating time promoted plumbagin degradation.

Antihypertensive effects of crude extracts from leaves of Echinodorus grandiflorus

The antihypertensive action of a crude ethanolic extract (EEEG) from leaves of Echinodorus grandiflorus (Alismataceae) was investigated in spontaneously hypertensive rats. The intraperitoneal injection of increasing doses of EEEG (300–1000 mg/kg) elicited dose‐dependent reductions in mean arterial pressure (MAP) that were paralleled by reductions of cardiac output and systemic vascular resistance, reaching the maximum of 23 ± 5%, 13 ± 3% and 18 ± 4%, respectively (n = 5, P < 0.05). Comparable reductions of MAP were obtained upon i.v. administration of EEEG (3–100 mg/kg), reaching the maximum decrease of 51 ± 6% (n = 7; P < 0.001). The blockade of nitric oxide synthesis significantly reduced the hypotension induced by i.v. administration of EEEG. Moreover, the pre‐treatment of the animals with a selective antagonist of cholinergic muscarinic receptors or of platelet‐activating factor (PAF) receptors partially blunted the cardiovascular effects of EEEG. The i.v. pre‐treatment with the selective B2 bradykinin receptor antagonist HOE 140 or with indomethacin, an inhibitor of the enzyme cyclooxygenase, did not prevent the hypotensive effects induced by EEEG. Finally, the chronic oral treatment with EEEG presented a significant antihypertensive effect that was comparable to that of reference antihypertensive drugs currently used to treat arterial hypertension. It is concluded that EEEG elicits significant acute antihypertensive effects through the release of nitric oxide and the stimulation of cholinergic muscarinic and PAF receptors. Moreover, our results suggest that EEEG may be appropriate to chronic oral treatment of arterial hypertension.

Perfil cromatográfico de duas espécies de Plumbaginaceae: Plumbago scandens L. E Plumbago auriculata Lam

The genus Plumbago belongs to the family Plumbaginaceae, order Plumbaginales. Comparative chemical profile of P. scandens (native) and P. auriculata (cultivated) was obtained by normal and reversed-phase high performance liquid chromatography with photodiode array detector. Comparison of the ultraviolet espectra and the retention times for the compounds allowed to find similar metabolic patterns in roots, stems and leaves. Four flavonoids, one phenolic acid or derivative and the naphtoquinone plumbagin were comparatively identified to standards.

Anti-inflammatory effect of Schinus terebinthifolius Raddi hydroalcoholic extract on neutrophil migration in zymosan-induced arthritis.

ETHNOPHARMACOLOGICAL RELEVANCE Schinus terebinthifolius is a species of plant from the Anacardiaceae family, which can be found in different regions of Brazil. Schinus is popularly known as aroeirinha, aroeira-vermelha, or Brazilian pepper. In folk medicine, S. terebinthifolius is used for several disorders, including inflammatory conditions, skin wounds, mucosal membrane ulcers, respiratory problems, gout, tumors, diarrhea and arthritis. According to chemical analyses, gallic acid, methyl gallate and pentagalloylglucose are the main components of hydroalcoholic extracts from S. terebinthifolius leaves. In the present study, we demonstrated the ability of a hydroalcoholic extract to inhibit cell migration in arthritis and investigated the mechanisms underlying this phenomenon. MATERIALS AND METHODS The anti-inflammatory effect of S. terebinthifolius hydroalcoholic leaf extract (ST-70) was investigated in a zymosan-induced experimental model of inflammation. Male Swiss and C57Bl/6 mice received zymosan (100 µg/cavity) via intra-thoracic (i.t.) or intra-articular (i.a.) injection after oral pre-treatment with ST-70. The direct action of ST-70 on neutrophils was evaluated via chemotaxis. RESULTS ST-70 exhibited a dose-dependent effect in the pleurisy model. The median effective dose (ED50) was 100mg/kg, which inhibited 70% of neutrophil accumulation when compared with the control group. ST-70 reduced joint diameter and neutrophil influx for synovial tissues at 6h and 24h in zymosan-induced arthritis. Additionally, ST-70 inhibited synovial interleukin (IL)-6, IL-1β, keratinocyte-derived chemokine (CXCL1/KC) and Tumor Necrosis Factor (TNF)-α production at 6h and CXCL1/KC and IL-1β production at 24h. The direct activity of ST-70 on neutrophils was observed via the impairment of CXCL1/KC-induced chemotaxis in neutrophils. Oral administration of ST-70 did not induce gastric damage. Daily administration for twenty days did not kill any animals. In contrast, similar administrations of diclofenac induced gastric damage and killed all animals by the fifth day. CONCLUSIONS Our results demonstrated significant anti-inflammatory effects of ST-70, suggesting a putative use of this herb for the development of phytomedicines to treat inflammatory diseases, such as joint inflammation.

Analgesic and anti-inflammatory activity of the aqueous extract of Rheedia longifolia Planch & Triana

Rheedia longifolia Planch et Triana belongs to the Clusiaceae family. This plant is widely distributed in Brazil, but its chemical and pharmacological properties have not yet been studied. We report here that leaves aqueous extract of R. longifolia (LAE) shows analgesic and anti-inflammatory effects. Oral or intraperitoneal administration of this extract dose-dependently inhibited the abdominal constrictions induced by acetic acid in mice. The analgesic effect and the duration of action were similar to those observed with sodium diclofenac, a classical non-steroidal analgesic. In addition to the effect seen in the abdominal constriction model, LAE was also able to inhibit the hyperalgesia induced by lipopolysaccharide from gram-negative bacteria (LPS) in rats. We also found that R. longifolia LAE inhibited an inflammatory reaction induced by LPS in the pleural cavity of mice. Acute toxicity was evaluated in mice treated with the extract for seven days with 50 mg/kg/day. Neither death, nor alterations in weight, blood leukocyte counts or hematocrit were noted. Our results suggest that aqueous extract from R. longifolia leaves has analgesic and anti-inflammatory activity with minimal toxicity and are therefore endowed with a potential for pharmacological control of pain and inflammation.

Diterpenes, taxonomic markers?

The chemosystematic potential of the 15 more common diterpene types in vascular plants was evaluated. Oxidation levels and skeletal specializations indicate diterpene biosynthesis to involve contrasting modes in pteridophytes and angiosperms on one hand, and in gymnosperms on the other. In angiosperm lineages diterpene diversification accompanies trends towards increase of herbaceousness and depletion of polyphenols, i.e., towards evolutionary advance. Nevertheless, even closely related families may display disjunctions of diterpene type and substitution. Thus the taxonomic value of this metabolic class remains confined to single (advanced) families.

Effect of Rheedia longifolia Leaf Extract and Fractions on the P2X7 Receptor In Vitro: Novel Antagonists?

Recently, the P2X(7) receptor has been reported to be associated with chronic inflammatory and neuropathic pain. Because Rheedia longifolia extract has analgesic and anti-inflammatory activity, we evaluated the in vitro inhibitory potential of methanol extract and fractions from its leaves on the P2X(7) purinergic receptor. The activity of P2X(7) was studied with a dye uptake assay and with the whole-cell patch clamp technique in mouse peritoneal macrophages treated with methanol extract of R. longifolia leaves and fractions. The dye uptake was evaluated by flow cytometry and fluorescence microscopy. The R. longifolia extract and some fractions showed an inhibitory effect on the P2X(7) purinergic receptor in a dose-dependent manner. The ethyl acetate fraction exhibited the most potent inhibitory effects. The methanol extract and the butanol fraction showed the same inhibitory effects, despite their lower potency compared with the other fractions. The R. longifolia extract and some of its fractions may be anti-inflammatory because of their inhibitory effect on the P2X(7) receptor. Further investigation is needed to determine the pattern of inhibition and selectivity. Chromatographic analysis indicated the presence of bisflavonoids in the methanol extract fractions. A member of this chemical family is the most probable active compound responsible for the P2X(7) inhibitory effects present in the R. Longifolia extract and fractions.