Anti-inflammatory and antialgic actions of a nanoemulsion of Rosmarinus officinalis L. essential oil and a molecular docking study of its major chemical constituents

Abstract

We evaluate the anti-inflammatory and antialgic potency of a nanoemulsion (NEORO) containing the essential oil of Rosmarinus officinalis L. (EORO), which is composed primarily of limonene, camphor and 1,8-cineole. The EORO and NEORO were administered orally 30 min prior to starting the experiments. In a test of rat paw oedema induced by carrageenan, NEORO was effective in doses of 498 µg/kg, and it inhibited 46% of the maximum peak of the oedema; in a dose of 300 mg/kg, EORO inhibited 50% of the maximum peak of the oedema. In an acetic acid-induced writhing test, NEORO yielded a dose-dependent effect, and a dose of 830 µg/kg inhibited 84% of the algesic process; a dose of 100 mg/kg of EORO inhibited 55%. In an assay for HS production in rat stomachs, a dose of 498 µg/kg of NEORO inhibited HS production in all of the measurement phases, and a dose of 100 mg/kg EORO inhibited 60% and influenced the effect of the ethanol significantly, reducing the production of HS. We suggest that NEORO potentiated the effect of EORO, demonstrating effectiveness in doses 600 times lower than those applied with EORO. Among the major compounds of EORO, the camphor molecule exhibited the largest number of interactions with the therapeutic targets related to the inflammatory process, suggesting that it is responsible for EORO's anti-inflammatory and antialgic effects. This work paves the way for future investigations related to the therapeutic role of NEORO in the inflammation process.

The effects of Rosmarinus officinalis L. essential oil and its nanoemulsion on dyslipidemic Wistar rats

“…That could be explained by EORO's reducing effect over TC, TG, and mainly LDL levels -an essential lipoprotein for atherogenesis. Borges et al (2017) demonstrated the anti-inflammatory potential of R. officinalis essential oil and its nanoemulsion, which also can contribute by inhibiting the inflammatory cascade that triggers inflammatory cells influx into the subendothelial region. Moreover, the antioxidant activity of EORO may also contribute inhibiting atherogenesis by suppressing LDL oxidation, preventing its absorption by macrophages, and hence preventing the formation of foam cells (Rašković et al, 2014).…”

“…The nanoemulsion was assessed 0, 1, and 7 days after its preparation for the following parameters: macroscopic color and visual aspect, phases separation, and sedimentation. Moreover, the droplets size analysis and polydispersity index were evaluated using a Zetasizer (Malvern, Nano Series) according to described by Borges et al (2017). The NE-ORO was kept at room temperature (25 ± 2 °C) in capped test tubes.…”

“…The dyslipidemia was induced on the second day by injecting Triton intraperitoneally (WR1339, Tyloxapol, Sigma-Aldrich) at 150 mg/kg dissolved in saline solution (Souza et al, 2017a). EORO and NEORO doses were chosen based on Borges et al (2017). The groups were designed as follows:…”

“…Animals were randomly assigned into five groups (n = 7 per group) and orally treated according to the CSF dyslipidemia-inducing method described by Souza et al (2017b). EORO and NEORO doses were chosen based on Borges et al (2017). The groups were designed as follows:…”

“…The essential oil of R. officinalis (EORO) is a colorless or pale-yellow liquid with the plant's characteristic scent (Rašković et al, 2014). Its chemical composition can differ according to the soil, farming factors, and extraction method (Borges et al, 2017). According to Cleff et al (2012) and Takayama et al (2016), the major compounds of this oil include 1,8-cineol, α-pinene, and limonene.…”