Cytotoxic activity of essential oil from Leaves of Myrcia splendens against A549 Lung Cancer cells

BACKGROUND

Plants of the Myrcia genus have been widely used in folk medicine to treat various diseases, including cancer. Myrcia splendens species has a diverse chemical constitution, but the biological activities of its essential oil have not been well investigated. In this study to out the chemistry characterization of essential oil (EO) from the leaves of the species M. splendens from Brazil and evaluate cytotoxic effect in A549 lung cancer cells.

METHODS

M. splendens EO was obtained by hydrodistillation and analyzed by Gas Chromatography-Mass Spectrometry (GC-MS). EO was isolated and evaluated for cellular viability in tumor cell lines by MTT assay. The evaluation of the formation of clones and the migratory capacity of the A549 cells treated with EO was done by the clonogenic assay and the wound healing assay. Morphological changes were observed in A549 cells by fluorescence using Phalloidin/FITC and DAPI.

RESULTS

22 compounds were identified in the chemical analysis of EO, corresponding to 88% of the sample. Major compounds were the sesquiterpenic hydrocarbons bicyclogermacrene (15.4%), germacrene D (8.9%) and E-caryophyllene (10.1%). The biological analysis of the EO showed high cytotoxic activity with an IC₅₀ below 20 µg/ml in the THP-1, A549 and B16-F10 tumor cells. The treatment with EO reduced colony formation and inhibited the migratory capacity of A549 cells. Furthermore, apoptotic morphological changes in the nucleus and cytoplasm of A549 cells was observed after of treatment with EO.

CONCLUSION

The findings of this study suggest that the M. splendens EO has cytotoxic compounds for the A549 lung cancer cells. Treatment with the EO decreased the colony formation and reduced the ability of lung cancer cells to migrate. Future studies may be used to isolate compounds from the EO for the study of lung cancer.

p-Cymene attenuates cancer pain via inhibitory pathways and modulation of calcium currents

BACKGROUND

Oncological pain is one of the most prevalent and difficult-to-treat symptoms in patients with cancer. p-Cymene (PC) is a monoterpene found in more than 100 different plant species, endowed with various pharmacological properties-particularly antinociceptive.

HYPOTHESIS/PURPOSE

PC has antinociceptive effect in a model of oncologic pain due to the activation of the descending inhibitory pathway of pain.

STUDY DESIGN

A pre-clinical, longitudinal, blind and randomized study.

METHODS

Male Swiss mice were induced with S180 cells in the right hind paw, then treated daily with PC (12.5, 25 and 50 mg/kg, s.c.) and screened for mechanical hyperalgesia, spontaneous nociception, nociception induced by non-noxious palpation, tumor growth, changes in the neuromuscular function and existence of bone degradation in the tumor area. The effect of PC on Ca²⁺ currents (electrophysiological records), histological and neurochemical changes (immunofluorescence for Fos) were also evaluated.

RESULTS

PC reduced (p < 0.05) the mechanical hyperalgesia, the spontaneous (p < 0.001) and non-noxious palpation (p < 0.001) nociceptions, not changing the tumor development, neuromuscular function or histopathological aspects of the paw affected. PC reduced Fos expression in the spinal cord (p < 0.001) and increased this expression in the PAG (p < 0.05) and in the NRM (p < 0.01). PC decreased the density of calcium channel currents (p < 0.05).

CONCLUSION

These results suggest the antinociceptive effect of PC on oncologic pain, probably acting in both ascending and descending pain pathways, and modulating the calcium channel currents in order to exert its effects.

The anti-hyperalgesic and anti-inflammatory profiles of p-cymene: Evidence for the involvement of opioid system and cytokines

CONTEXT

Pain corresponds to the most frequent reason for visits to physicians, and its control by conventional drugs is accompanied by several side effects, making treatment difficult. For this reason, new chemical entities derived from natural products still hold great promise for the future of drug discovery to pain treatment.

OBJECTIVE

The objective of this study was to evaluate the antinociceptive and anti-inflammatory profiles of p-cymene (PC), a monocyclic monoterpene, and its possible mechanisms of action.

MATERIALS AND METHODS

Mice treated acutely with PC (25, 50, or 100 mg/kg, i.p.) were screened for carrageenan-induced hyperalgesia and the inflammatory components of its cascade (30-180 min), carrageenan-induced pleurisy (4 h), and tail-flick test (1-8 h). Also, we observed the PC effect on the generation of nitric oxide by macrophages and the activation of neurons in the periaqueductal gray (PAG) by immunofluorescence.

RESULTS

PC reduced (p < 0.001) the hyperalgesia induced by carrageenan, TNF-α, dopamine, and PGE2. PC decrease total leukocyte migration (100 mg/kg: p < 0.01), neutrophils (50 and 100 mg/kg: p < 0.05 and 0.001), and TNF-α (25, 50, and 100 mg/kg: p < 0.01, 0.05, and 0.001, respectively), besides reducing NO production (p < 0.05) in vitro. PC produced antinociceptive effect in tail-flick test (p < 0.05), which was antagonized by naloxone, naltrindole, nor-BNI, and CTOP, and increased (p < 0.001) the number of c-Fos-immunoreactive neurons in PAG.

DISCUSSION AND CONCLUSION

These results provide information about the anti-hyperalgesic and anti-inflammatory properties of PC suggesting a possible involvement of the opioid system and modulating some pro-inflammatory cytokines.

β-cyclodextrin complex containing Lippia grata leaf essential oil reduces orofacial nociception in mice - evidence of possible involvement of descending inhibitory pain modulation pathway

The treatment of orofacial pain remains a major challenge for modern medicine. Thus, we prepared and physicochemically characterized a new β-cyclodextrin complex containing Lippia grata leaf essential oil (β-CD/EO) to investigate their possible antinociceptive activity in animal models of orofacial pain. The results of Differential scanning calorimeter (DSC) and Thermogravimetry/derivative thermogravimetry (TG/DTG) showed that the products prepared by Slurry complexation (SC) method were able to incorporate greater amounts of EO. In the X-ray diffractogram, it was shown that complex between EO and β-CD was formed. Male Swiss mice were pre-treated with β-CD/EO (6, 12 or 24 mg/kg, per os, gavage, p.o.), morphine (5 mg/kg, i.p.) or vehicle (distilled water, p.o.) 1 hr before treatment with formalin (20 μL, 2%), capsaicin (20 μL, 2.5 μg) or glutamate (40 μL, 25 μM) into the right upper lip. Our results demonstrated that p.o. treatment with β-CD/EO was significantly (p < 0.05 or p < 0.001) capable of reducing the nociceptive face-rubbing behaviour in both phases of the formalin test. β-CD/EO-treated mice were also significantly (p < 0.05 or p < 0.001) protected against nociception induced by capsaicin and glutamate. For the action in the central nervous system (CNS), ninety minutes after the treatment, the mice were perfused, the brains collected, crioprotected, cut in a criostate and submitted to an immunofluorescence protocol for Fos protein. The immunofluorescence protocol demonstrated that the β-CD/EO significantly activated (p < 0.05; p < 0.01 or p < 0.001) the motor cortex, the Locus ceruleus, the nucleus raphe magnus and the periaqueductal gray of the CNS. These effects apparently did not alter, in tested doses, the motor coordination of mice in the rota-rod test. Our results proposed that β-CD/EO might present an important draft of drug to the study of new compounds for the treatment of orofacial pain.

Citronellol reduces orofacial nociceptive behaviour in mice - evidence of involvement of retrosplenial cortex and periaqueductal grey areas

Citronellol (CT) is a monoterpenoid alcohol present in the essential oil of many medicinal plants, such as Cymbopogon citratus. We evaluated the antinociceptive effects of CT on orofacial nociception in mice and investigated the central pathway involved in the effect. Male Swiss mice were pretreated with CT (25, 50 and 100 mg/kg, i.p.), morphine (5 mg/kg, i.p.) or vehicle (saline + tween 80 0.2%). Thirty minutes after the treatment, we injected formalin (20 μl, 2%), capsaicin (20 μl, 2.5 μg) or glutamate (40 μl, 25 μM) into the right limb. For the action in the CNS, ninety minutes after the treatment, the animals were perfused, the brains collected, crioprotected, cut in a criostate and submitted in an immunofluorescence protocol for Fos protein. CT produced significant (p < 0.01) antinociceptive effect, in all doses, in the formalin, capsaicin and glutamate tests. The immunofluorescence showed that the CT activated significantly (p < 0.05) the olfactory bulb, the piriform cortex, the retrosplenial cortex and the periaqueductal grey of the CNS. Together, our results provide first-time evidence that this monoterpene attenuates orofacial pain at least, in part, through an activation of CNS areas, mainly retrosplenial cortex and periaqueductal grey.