Antinociceptive effect of Lonchocarpus araripensis lectin: activation of L-arginine/NO/cGMP/K+ATP signaling pathway.

OBJECTIVE AND DESIGN: The involvement of nitric oxide pathway in the antinociceptive activity of Lonchocarpus araripensis lectin (LAL) was investigated in the model of carragenan-induced hypernociception. METHODS: Swiss mice received LAL (0.01-10 mg/kg; i.v.) 30 min before s.c. injection of carragenan in the paws. For the involvement of nociceptive pathways, animals were previously treated with the blockers: NOS (L-NAME, aminoguanidine, 7-nitroindazole); soluble guanylyl cyclase (ODQ); channels of ATP-dependent K+ (glibenclamide); L-type Ca2+ (nifedipine), or Ca2+-dependent Cl- (niflumic acid). Participation of lectin domain was evaluated by injection of LAL associated with N-acetyl-glucosamine (GlcNAc). nNOS gene relative expression was evaluated in the paw tissues and nNOS immunostaining in dorsal root ganglia. RESULTS: LAL at all doses inhibited carrageenan-induced hypernociception (4.12 ± 0.58 g), being maximal at 10 mg/kg (3 h: 59%), and reversed by GlcNAc. At this time, LAL effect was reversed by nifedipine (39%), niflumic acid (59%), L-NAME (59%), 7-nitroindazole (44%), ODQ (45%), and glibenclamide (34%), but was unaltered by aminoguanidine. LAL increased (95%) nNOS gene expression in mice paw tissues, but not its immunoexpression in the dorsal root ganglia. CONCLUSION: The antinociceptive effect of Lonchocarpus araripensis lectin involves activation of the L-arginine/NO/GMPc/K+ATP pathway.

Lectin purified from Lonchocarpus campestris seeds inhibits inflammatory nociception.

Lonchocarpus campestris (tribe Dalbergieae) possess a mannose biding lectin (LCaL) purified by ion exchange chromatography on DEAE-Sephacel, HiTrap DEAE FF and TSKgel engaged in AKTA-HPLC system. LCaL agglutinates trypsinized rabbit erythrocytes and its activity was maintained after incubation in a wide range of temperature (4-100 °C) and pH (4-9). The lectin had its apparent molecular weight evaluated by size-exclusion chromatography and SDS-PAGE and presented a profile of 10 kDa and 25 kDa in denaturing and native conditions, respectively. LCaL injected by intravenous route in mice showed antinociceptive activity in the behavioral tests of Formalin and Writhing. In the formalin test LCaL inhibited the licking time by 37% in the neurogenic phase and by 73% in the inflammatory phase. In the acetic acid-induced writhing test LCaL showed inhibitory effect at 0.1 mg/kg (72%), 1 mg/kg (74%) and 10 mg/kg (70%). The lectin also inhibited the increase in vascular permeability at 10 mg/kg and leukocyte migration at 0.1, 1 and 10 mg/kg concentrations. Additionally, LCaL inhibited paw edema (mainly from 1 to 3 h by 46%) and hyperalgesia (1 h: 82%; 3 h: 63%) induced by carrageenan. In conclusion, LCaL presents an antinociceptive action mainly via inhibition of inflammation.

Calycophyllum spruceanum BENTH ameliorates acute inflammation in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Calycophyllum spruceanum (Benth.) Hook. F. ex K. Schum. is widely distributed in the Amazonian region of Brazil, where it is popularly known as "mulateiro", "pau-mulato", "pau-mulato-de-várzea", "escorrega-macaco" or "pau-marfim". Preparations of C. spruceanum barks are used in the form of tea, poultice or skin patches to treat stomach diseases, skin inflammation and uterus tumors. PURPOSE OF THE STUDY: To investigate in vivo the antinociceptive and anti-inflammatory activities of the hydroalcoholic extract of Calycophyllum spruceanum barks (HECSb) in order to validate its popular usage in inflammatory conditions. MATERIALS AND METHODS: Chemical analysis of HECSb was performed using the UHPLC-MS system. Mice were treated per oral with HECSb (5-5000 mg/kg) and evaluated for acute toxicity (during 15 days); motor activity (Rota rod test); body weight (up to 72 h); antinociceptive activity: writhes induced by 0.8% acetic acid; paw licking induced by 2.5% formalin; paw withdrawal (von Frey test) induced by carrageenan (300 µg) or PGE2 (100 ng); anti-inflammatory (paw edema model). For histopathological analysis subplantar tissue fragments were collected 1 h after paw edema induction. RESULTS: HECSb chemical analysis revealed the presence of caffeoylquinic derivatives, small organic acids, and phenolic compounds. HECSb showed antinociceptive effect, reducing the number of acetic acid-induced writhes by 72% at 120 mg/kg, paw licking (phase 2- Formalin test) by 33% at 60 mg/kg and 49% at 120 mg/kg; and paw withdrawal elicited by carrageenan (53% at 120 mg/kg) and PGE2 (120 mg/kg) at 0.5 h (48%) and 1 h (45%). HECSb (120 mg/kg) also inhibited the paw edema elicited both by carrageenan (48%) and PGE2 (92%). Histopathological analysis (leukocyte infiltration, edema, focal areas of hemorrhage, vascular congestion) of HECSb treatment at 120 mg/kg demonstrated normal morphology [median 0 (0,1)] compared to PGE2, showing severe alterations [median 3 (2,3); p = 0,0035]. HECSb did not induce acute toxicity nor altered body mass or motor coordination. CONCLUSIONS: HECSb shows antinociceptive and anti-inflammatory effect in mice without inducing apparent acute toxicity.

Structural characterization of a lectin from Canavalia virosa seeds with inflammatory and cytotoxic activities.

A lectin from Canavalia virosa, Diocleinae subtribe, was purified by affinity chromatography with Sephadex G-50 matrix and named ConV. The primary structure of ConV was obtained by mass spectrometry and crystals were obtained by the vapor diffusion method at 293K and belonged to orthorhombic space group P21221 with two molecules in its asymmetric unit. The structure obtained presented Rfactor and Rfree of 18.91% and 24.92% respectively, with no residues in nonallowed regions of Ramachandran plot. The crystal structure was solved at 2.53Å and was demonstrated to be very similar to other lectins from the same subtribe. In inflammatory tests, ConV elicited paw edema, but incubation of lectin with glucose beforehand was able to reduce the edematogenic effect, indicating the involvement of the carbohydrate recognition domain in this process. The lectin also showed toxicity to rat C6 glioma cells, disrupting the mitochondrial membrane potential (ΔYm) and decreasing cell viability, indicating an anticancer potential for ConV. In silico studies confirmed that ConV interacts strongly with carbohydrates that comprise the N-glycans of glycoproteins. This finding corroborates the hypothesis which holds that the lectin domain interacts with glycans in molecular targets and that this contributes to the effects observed in biological activities.

The leguminous lectin of Lonchocarpus araripensis promotes antinociception via mechanisms that include neuronal inhibition of Na(+) currents.

OBJECTIVE AND DESIGN: Sodium channels are highly expressed in nociceptive sensory neurons during hypernociceptive conditions. Based on the presence of a glycosidic portion in the sodium channel ß subunit associated to the antinociceptive effect of leguminous lectins via lectin domain, this study investigated the antinociceptive activity of the lectin isolated from Lonchocarpus araripensis seeds (LAL) in mice behavioral models and in NaV current in the nociceptor of rat dorsal root ganglion (DRG). MATERIAL/METHODS: LAL antinociceptive activity and the participation of opioid system, lectin domain and sodium channels were evaluated in Swiss mice models of nociception (formalin, capsaicin, hot plate, tail flick, von Frey) and in primary cultures of Wistar rats neurons of DRG (patch clamp). RESULTS: LAL presented inhibitory effects in the nociception induced by chemical and mechanical, but not by thermal stimuli and reduced total Na(+) current. LAL activity was inhibited by the lectin association with its binding sugar N-acethyl-glucosamine. CONCLUSION: LAL inhibits peripheral hypernociception by mechanisms that involve the lectin domain, inflammatory mediators and Na(+) channels. The innovative inhibitory action of leguminous lectins on NaV current brings new insights for the investigation of sodium channels role in nociception.

Edematogenic activity of a sulfated galactan from the red marine algae Gelidium crinale.

CONTEXT: The red algae Gelidium crinale (Turner) Gaillon (Gelidiaceae), encountered along the Southeast and Northeast Brazilian sea coast, contains a sulfated galactan presenting a similar saccharide backbone compared to λ carrageenan. Inflammatory effects of other galactans were reported, but not for that obtained from G. crinale (SG-Gc). OBJECTIVE: To investigate the in vivo edematogenic effect of SG-Gc in comparison to λ carrageenan. METHODS: SG-Gc was isolated by ion exchange chromatography. Paw edema was induced by subcutaneous (s.c.) intraplantar injection of SG-Gc or λ carrageenan and evaluated by hydroplethysmometry. Data were expressed as the increase in paw volume subtracted from the basal volume or area under curve-AUC. To investigate the participation of early and late-phase inflammatory mediators, rats were treated with pyrilamine, compound 48/80, indomethacin, NG-nitro-L-arginine methyl ester (L-NAME), or pentoxifylline before SG-Gc. RESULTS: SG-Gc edematogenic effect was initiated at 0.5 h, peaked at 2 h (1.26 ± 0.05 mL) and lasted until 6 h (0.21 ± 0.03 mL), whereas the carrageenan-induced edema started at 1 h. The first phase (1-3 h) of SG-Gc-induced edema was 176 ± 15 (AUC) versus carrageenan (114.5 ± 14), whereas the second phase (3-5 h) was 95 ± 12 (AUC) versus carrageenan (117.5 ± 11). Treatment with compound 48/80, pyrilamine, indomethacin, L-NAME, and pentoxifylline inhibited the effect of SG-Gc by 32, 40, 69, 72, and 49%, respectively. DISCUSSION AND CONCLUSION: SG-Gc and λ carrageenan induce different profile of inflammatory response in the paw edema model, that involves histamine, cytokines, prostaglandins, and nitric oxide (NO), but with different degree of participation.