Isolation and primary structure of proteinase inhibitors from Erythrina variegata (Linn.) var. Orientalis seeds.
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The Kunitz-type trypsin inhibitors, ETIa and ETIb, and chymotrypsin inhibitor ECI were isolated from the seeds of Erythrina variegata. The proteins were extracted from a defatted meal of seeds with 10 mM phosphate buffer, pH 7.2, containing 0.15 M NaCl, and purified by DEAE-cellulose and Q-Sepharose column chromatographies. The stoichiometry of trypsin inhibitors with trypsin was estimated to be 1:1, while that of chymotrypsin inhibitor with chymotrypsin was 1:2, judging from the titration patterns of their inhibitory activities. The complete amino acids of the two trypsin inhibitors were sequenced by protein chemical methods. The proteins ETIa and ETIb consist of 172 and 176 amino acid residues and have M(r) 19,242 and M(r) 19,783, respectively, and share 112 identical amino acid residues, which is 65% identity. They show structural features characteristic of the Kunitz-type trypsin inhibitor (i.e., identical residues at about 45% with soybean trypsin inhibitor STI). Furthermore, the trypsin inhibitors show a significant homology to the storage proteins, sporamin, in sweet potato and the taste-modifying protein, miraculin, in miracle fruit, having about 30% identical residues. (+info)
Effects of chronic treatment with a water-alcohol extract from Erythrina mulungu on anxiety-related responses in rats.
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We investigated the effects of chronic oral treatment with a water-alcohol extract from the inflorescence of Erythrina mulungu (Leguminosae-Papilionaceae) (EM, 50, 100, 200 mg/kg) in rats submitted to different anxiety models: the elevated T-maze (ETM, for inhibitory avoidance and escape measurements), the light/dark transition, and the cat odor test. These models were selected for their capacity to elicit specific subtypes of anxiety disorders as recognized in clinical practice. Treatment with EM impaired inhibitory avoidance latencies in a way similar to the reference drug, diazepam (DZP). Additionally, both EM and DZP increased the number of transitions and the time spent in the lighted compartment of the light/dark transition model. Furthermore, neither EM nor DZP altered behavioral responses of rats to a cloth impregnated with cat odor. In contrast to DZP, however, EM also altered ETM one-way escape. These results were not due to motor alterations since no significant effects were detected in the number of crossings or rearings in the arena. The present observations suggest that chronic EM exerts anxiolytic-like effects in defensive behaviors related to generalized anxiety and panic disorder. Although alkaloids appear to be one of the main constituents of EM, the possible mechanisms through which the extract exerts its anxiolytic action should be further investigated. (+info)
Crystal structures of Erythrina cristagalli lectin with bound N-linked oligosaccharide and lactose.
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Erythrina cristagalli lectin (ECL) is a galactose-specific legume lectin. Although its biological function in the legume is unknown, ECL exhibits hemagglutinating activity in vitro and is mitogenic for T lymphocytes. In addition, it has been recently shown that ECL forms a novel conjugate when coupled to a catalytically active derivative of the type A neurotoxin from Clostridium botulinum, thus providing a therapeutic potential. ECL is biologically active as a dimer in which each protomer contains a functional carbohydrate-combining site. The crystal structure of native ECL was recently reported in complex with lactose and 2'-fucosyllactose. ECL protomers adopt the legume lectin fold but form non-canonical dimers via the handshake motif as was previously observed for Erythrina corallodendron lectin. Here we report the crystal structures of native and recombinant forms of the lectin in three new crystal forms, both unliganded and in complex with lactose. For the first time, the detailed structure of the glycosylated hexasaccharide for native ECL has been elucidated. The structure also shows that in the crystal lattice the glycosylation site and the carbohydrate binding site are involved in intermolecular contacts through water-mediated interactions. (+info)
Phomol, a new antiinflammatory metabolite from an endophyte of the medicinal plant Erythrina crista-galli.
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Phomol (1), a novel antibiotic, was isolated from fermentations of a Phomopsis species in the course of a screening of endophytic fungi from the medicinal plant Erythrina crista-galli. For this Argentinean leguminosa antiinflammatory and neuroleptic activities have been described. The compound exhibits antifungal, antibacterial and weak cytotoxic acticity. The antiinflammatory activity was tested in different reporter gene assays (TNF-alpha, STAT1/STAT2 and NF-kappaB) and in an ear edema model in mice. In the reporter gene assays 1 exhibited no activity, whereas 1 showed interesting antiinflammatory activity in the mouse ear assay. The compound is a polyketide lactone and its structure was elucidated by spectroscopic methods. (+info)
Contribution of conserved Asn residues to the inhibitory activities of Kunitz-type protease inhibitors from plants.
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Plant Kunitz-type protease inhibitors contain a conserved Asn residue in the N-terminal region. To investigate the role of Asn residue in protease inhibitory activities, Erythrina variegata trypsin inhibitor a (ETIa), E. variegata chymotrypsin inhibitor (ECI), and their mutants, ETIa-N12A and ECI-N13A, were used. Both mutants exhibit weaker inhibitory activities toward their cognate proteases than the wild-type proteins and were readily cleaved at reactive sites. Furthermore, kinetic analysis of the interactions of the mutated proteins with their cognate proteases by surface plasmon resonance (SPR) measurement indicated that replacements of the Asn residue mainly affected dissociation rate constants. The conserved Asn residues of Kunitz-type inhibitors play an important role in exhibiting effective inhibitory activity by stabilizing the structures of the primary binding loop and protease-inhibitor complex. (+info)
Expression of Erythrina corallodendron lectin in Escherichia coli.
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The cDNA of the Erythrina corallodendron lectin (ECorL) has been expressed in Escherichia coli. For this purpose, an NcoI site was inserted into the cDNA coding for the lectin precursor [Arango, R., Rozenblatt, S. & Sharon, N. (1990) FEBS Lett. 264, 109-112] immediately before the codon GTG (103-105) which codes for the N-terminal valine of the mature lectin. This introduced an ATG codon for a methionine preceding the valine. The mutated cDNA was ligated into pUC-8, then subcloned into the expression vector pET-3d, which carries a strong promoter derived from gene 10 of the phage T7. The recombinant plasmid was introduced into the E. coli lysogenic strain BL21(DE3). Recombinant ECorL was expressed by growing the bacteria in the presence of isopropyl beta-D-thiogalactopyranoside. Most of the recombinant lectin was found in an insoluble aggregated form as inclusion bodies and only a small part was in the culture medium in a soluble active form. Functional recombinant lectin was recovered from the inclusion bodies by solubilization with 6 M urea in cyclohexylaminopropane sulfonate pH 10.5, renaturation by 10-fold dilution in the same buffer and further adjustment of the pH to 8.0. The recombinant lectin, obtained at a yield of 4-7 mg/l culture, had, by gel filtration, a slightly lower molecular mass (56 kDa) than the native lectin, and was devoid of covalently linked carbohydrate; it was, however, essentially indistinguishable from native ECorL by other criteria, including its dimeric structure, Western blot analysis with anti-ECorL polyclonal and monoclonal antibodies, and Ouchterlony double-diffusion analysis with polyclonal antibodies, as well as hemagglutinating activity and specificity for mono- or disaccharides. (+info)
Ethnopharmacological survey of different uses of seven medicinal plants from Mali, (West Africa) in the regions Doila, Kolokani and Siby.
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An ethnopharmacological survey was carried out to collect information on the use of seven medicinal plants in rural areas in the nearby regions of Bamako, Mali. The plants were Opilia celtidifolia, Anthocleista djalonensis, Erythrina senegalensis, Heliotropium indicum, Trichilia emetica, Piliostigma thonningii and Cochlospermum tinctorium. About 50 medical indications were reported for the use of these plants in traditional medicine. The most frequent ailments reported were malaria, abdominal pain and dermatitis. The highest number of usages was reported for the treatment of malaria (22%). The majority of the remedies were prepared from freshly collected plant material from the wild and from a single species only. They were mainly taken orally, but some applications were prepared with a mixture of plants or ingredients such as honey, sugar, salt, ginger and pepper. Decoction of the leaves was the main form of preparation (65%) and leaf powder was mostly used for the preparation of infusions (13%). The part of the plants most frequently used was the leaves. There was a high degree of informant consensus for the species and their medicinal indications between the healers interviewed. The results of this study showed that people are still dependent on medicinal plants in these rural areas of Mali. (+info)
Synthesis of the erythrina alkaloid 3-demethoxyerythratidinone. Novel acid-induced rearrangements of its precursors.
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[reaction: see text] A new strategy for the synthesis of 3-demethoxyerythratidinone has been developed and is based on an extraordinarily facile intramolecular Diels-Alder reaction of a 2-imido-substituted furan. During the course of the synthesis, several novel acid-induced rearrangement reactions were encountered. (+info)