Chemical composition, antinociceptive, anti-inflammatory and redox properties in vitro of the essential oil from Remirea maritima Aubl. (Cyperaceae).

Background: The present study was carried out to evaluate antioxidant, antinociceptive and anti-inflammatory activities of essential oil from R. maritima (RMO) in experimental protocols.

Methods: The essential oil from the roots and rhizomes of RMO were obtained by hydrodistillation using a Clevenger apparatus, and analyzed by gas chromatography/mass spectrometry (GC/MS). Here, we evaluated free radical scavenging activities and antioxidant potential of RMO using in vitro assays for scavenging activity against hydroxyl radicals, hydrogen peroxide, superoxide radicals, and nitric oxide. The total reactive antioxidant potential (TRAP) and total antioxidant reactivity (TAR) indexes and in vitro lipoperoxidation were also evaluated. The ability of RMO to prevent lipid peroxidation was measured by quantifying thiobarbituric acid-reactive substances (TBARS). NO radical generated at physiological pH was found to be inhibited by RMO, that showed scavenging effect upon SNP-induced NO production at all concentrations. Antinociceptive and anti-inflammatory properties were evaluated by acetic acid writhing reflex, Formalin-induced nociception and Carrageenan-induced edema test.

Results: The majors compounds identified was remirol (43.2%), cyperene (13.8%), iso-evodionol (5.8%), cyperotundone (5.7%), caryophyllene oxide (4.9%), and rotundene (4.6%). At the TRAP assay, RMO concentration of 1 mg.mL(-1) showed anti-oxidant effects and at concentration of 1 and 10 ng.mL(-1) RMO showed pro-oxidant effect. RMO at 1 mg.mL(-1) also showed significant anti-oxidant capacity in TAR measurement. Concentrations of RMO from 1 ng.mL(-1) to 100 μg.mL(-1) enhanced the AAPH-induced lipoperoxidation. RMO reduced deoxyribose oxidative damage, induced by the Fenton reaction induction system, at concentrations from 1 ng.mL(-1) to 100 μg.mL(-1). We observed that RMO caused a significant increase in rate of adrenaline auto-oxidation. On the other hand RMO did not present any scavenging effect in H2O2 formation in vitro. The results of this study revealed that RMO has both peripheral and central analgesic properties. The RMO, all doses, orally (p.o.) administered significantly inhibited (p < 0.05, p < 0.01 and p < 0.001) the acetic acid-induced writhings and two phases of formalin-induced nociception in mice.

Conclusion: The RMO demonstrated antioxidant and analgesic profile which may be related to the composition of the oil.