Bio-guided study of the antinociceptive, anti-inflammatory, and free-radical scavenging capacity of the leaves of Rhus virens Lindh. ex A. Gray and its possible mechanism of antinociception.

ETHNOPHARMACOLOGICAL RELEVANCE: Rhus genus is commonly known as sumac and widely used in the folk medicine. Rhus virens is a plant commonly used to treat diabetes or pain in the northern territory of Mexico. Even though R. virens is used in the folk medicine there is still a lack of evidence about the pharmacological effect of this species. AIM OF THE STUDY: The aim of this study was to determine the antinociceptive, anti-inflammatory and antioxidant effect of R. virens through a bio-guided chemical separation. MATERIALS AND METHODS: The aqueous, methanolic, and hexane extract of R. virens were obtained and tested in the formalin test, TPA-induced ear edema, and DPPH, ABTS, and FRAP assay. Also, possible interaction of pain pathways was studied using naloxone, bicuculline, L-NAME, ODQ, and glibenclamide in the formalin test in mice. RESULTS: Rhus virens methanolic extract (30 mg/kg, p.o.) produced higher antinociceptive activity in both the early and late phases of the formalin test (35.0 and 52.9%, respectively). Also, pre-administration with naloxone, bicuculline, L-NAME, ODQ and glibenclamide prevented the antinociceptive effect of R. virens in the early phase of the formalin test. Meanwhile, only naloxone and bicuculline prevented the antinociceptive effect on the late phase of the formalin test. Chemical separation of methanolic extract allowed to isolate 1,2,3,4,6-penta-O-galloyl-glucopyranose (PGG), it was tested in the formalin test, producing an antinociceptive effect on the late phase of the formalin test. On the other hand, topical application of the derivatives of R. virens methanolic extract produced an anti-inflammatory effect in the TPA-induced ear edema, being PGG an anti-inflammatory molecule. Lastly, radical scavenging activity was higher in the extracts of higher polarity, comparable to the standard used Camellia sinensis. CONCLUSIONS: In conclusion, R. virens produce an antinociceptive, anti-inflammatory and free-radical scavenging activity. The antinociceptive effect could be related to the opioidergic, GABAergic, and NO-GMPc-K + ATP channels pathways. These effects could be partially produced by the presence of PGG.

Antinociceptive and anti-inflammatory effect of a standardized fraction of Oenothera rosea L'Hér. ex Aiton and its possible mechanism of action in mice.

Objective: This study was conducted to investigate the antinociceptive and anti-inflammatory effect of ethyl acetate fraction of Oenothera rosea (EAOr) and the mechanism involved, in mice. Materials and Methods: The antinociceptive activity was tested using chemical- and heat-induced nociception models. The anti-inflammatory activity was tested using carrageenan-induced edema and inflammatory cytokines were measured. Results: EAOr reduced the licking time on the second phase of the formalin test (100 and 177 mg/kg). The antinociception of EAOr was prevented by L-NAME (10 mg/kg), 1H-[1, 2, 4]-oxadiazolo [4, 3-a]-quinoxalin-1-one (ODQ, 0.1 mg/kg), glibenclamide (10 mg/kg) and bicuculline (1 mg/kg), but not by naloxone (2 mg/kg). Also, EAOr decreased licking time in capsaicin induced-nociception. EAOr did not have effect on withdrawal latency in tail-flick test. Carrageenan-induced paw edema was reduced by EAOr, and TNF-α and IL-1ß levels were reduced in mice treated with EAOr by 72.2 and 32.8%, respectively. Furthermore, EAOr did not present side effects as sedation nor gastric injury. Chemical analysis of this fraction showed the presence of glycosylated quercetin derivatives such as quercetin glucoside and quercetin rhamnoside in a 2.5% concentration. Conclusion: This study demonstrates antinociceptive and anti-inflammatory effect of an organic fraction of O. rosea and its possible interaction with the NO-cGMP-K+ channels and GABAergic system and thus, it could be considered a therapeutic alternative.

Immunomodulatory Effect of Agave tequilana Evaluated on an Autoimmunity Like-SLE Model Induced in Balb/c Mice with Pristane.

In this work, the immunomodulatory activity of the acetone extract and the fructans obtained from Agave tequilana were evaluated, on the systemic autoimmunity type-SLE model generated by the administration of 2,6,10,14-tetramethylpentadecane (TMPD, also known as pristane) on Balb/c female mice. The systemic autoimmunity type-SLE was observed seven months after the application of TMPD, in which the animals from the negative control group (animals with damage and without any other treatment) developed articular inflammation, proteinuria, an increment of the antinuclear antibody titters and tissue pro-inflammatory cytokines levels (IL-1ß, IL-6, TNF-α e IFN-γ) as well as the anti-inflammatory cytokine IL-10. The administration of the different treatments and the extracts of A. tequilana, provoked the decrease of: articular inflammation, the development of proteinuria, ssDNA/dsDNA antinuclear antibody titters and cytokines IL-1ß, IL-6, TNF-α, IFN-γ and IL-10. The phytochemical analysis of the acetone extract identified the presence of the following compounds: ß-sitosterol glycoside; 3,7,11,15-tetramethyl-2-hexadecen-1-ol (phytol); octadecadienoic acid-2,3-dihydroxypropyl ester; stigmasta-3,5-dien-7-one; cycloartenone and cycloartenol. Therefore, A. tequilana contains active compounds with the capacity to modify the evolution of the systemic autoimmunity type-SLE on a murine model.