ABSTRACT
Citral ((2E)-3,7-dimethylocta-2,6-dienal), a bioactive component of lemongrass, inhibits oxidant activity, nuclear factor kappa B (NF-κB) activation, and cyclooxygenase-2 (COX-2) expression, even as it activates peroxisome proliferator-activated receptor (PPAR)-α and γ. Additionally, citral produces long-lasting inhibition of transient receptor potential (TRP) channels that are found in sensory neurons, such as TRPV1-3 and TRPM8, while it transiently blocks TRPV4 and TRPA1. Here, the effect of citral in experimental models of acute inflammation and hyperalgesia in mice, and the underlying citral mechanisms of action were investigated. ADMET properties and molecular targets were predicted using the online server. The immunomodulatory and antihyperalgesic effects of citral were evaluated, using mechanical and thermal stimuli, at different time-points on carrageenan, lipopolysaccharides (LPS), and zymosan-induced paw edema and hyperalgesia in mice. ADMET analysis ensures that the citral has not violated Lipinski's rule of five, indicating its safety consumption, and molecular target prediction software identified that citral is a potential fatty acid amide hydrolase (FAAH) inhibitor. Oral treatment with citral (50-300 mg/kg) significantly inhibited carrageenan-induced paw edema and thermal allodynia. Furthermore, citral modulated the inflammation induced by LPS and zymosan, toll-like receptor (TLR) 4, and TLR2/dectin-1 ligands, respectively. Moreover, pretreatment with cannabinoid receptor type 2 (CB2R) antagonists and ATP-sensitive K+ channel inhibitor, but not with a cannabinoid receptor type 1 (CB1R) antagonist, significantly reversed the anti-inflammatory effect of citral. Intriguingly, citral did not cause any relevant action in the central nervous system, and it was safe when assessed in a 14 day toxicity assay in male mice. Therefore, citral constitutes a promising, innovative, and safe molecule for the management of immunoinflammatory conditions and pain states.
Subject(s)
Acyclic Monoterpenes/pharmacology , Adenosine Triphosphate/chemistry , Amidohydrolases/chemistry , Analgesics/pharmacology , Inflammation/metabolism , Lectins, C-Type/chemistry , Monoterpenes/pharmacology , Receptor, Cannabinoid, CB2/chemistry , Toll-Like Receptor 4/chemistry , Amidohydrolases/metabolism , Animals , Hyperalgesia/drug therapy , Hyperalgesia/metabolism , Inflammation/drug therapy , Lectins, C-Type/metabolism , Mice , Molecular Structure , Monoterpenes/chemistry , Receptor, Cannabinoid, CB2/therapeutic use , TRPV Cation Channels/chemistry , TRPV Cation Channels/metabolism , Toll-Like Receptor 2ABSTRACT
BACKGROUND: Transdermal delivery is an alternative route for the administration of drugs. However, it requires the development of vehicles that allow the drugs to cross the layers of the skin and reach the systemic circulation. OBJECTIVE: In this study, a new transdermal vehicle was evaluated using progesterone, estradiol, estradiol + estriol (Biest) and ketoprofen administered as model drugs. METHODS: To evaluate the ex vivo permeation of the drugs, the Franz vertical diffusion cell with human skin was used. RESULTS: After 24 h, the vehicle was able to deliver 18.32 µg/cm2 of progesterone and 92.07 µg/cm2 of ketoprofen through the skin to the receptor medium. The permeation percentages were 91%, 78.8%, 48.5%, 73.2%, and 63.6%, respectively, for estradiol, estradiol (Biest), estriol (Biest), progesterone and ketoprofen. For all drugs, sufficient amounts were delivered to achieve a systemic effect, and it was also possible to decrease the amount of emulsion applied. CONCLUSION: Thus, the vehicle demonstrated a high performance and the possibility of it being used for drugs that present difficulties in regards to administration by the transdermal route.
