Cyclodextrin-complexed Ocimum basilicum leaves essential oil increases fos protein expression in the central nervous system and produce an antihyperalgesic effect in animal models for fibromyalgia
O. basilicum leaves produce essential oils (LEO) rich in monoterpenes. The
short half-life and water insolubility are limitations for LEO medical uses. β-Cyclodextrin
(β-CD) has been employed to improve the pharmacological properties of LEO. We
assessed the antihyperalgesic profile of LEO, isolated or complexed in β-CD (LEO/β-CD),
on an animal model for fibromyalgia. Behavioral tests: mice were treated every day with
either LEO/β-CD (25, 50 or 100 mg/kg, p.o.), LEO (25 mg/kg, p.o.), tramadol (TRM
4 mg/kg, i.p.) or vehicle (saline), and 60 min after treatment behavioral parameters were
assessed. Therefore, mice were evaluated for mechanical hyperalgesia (von Frey), motor
coordination (Rota-rod) and muscle strength (Grip Strength Metter) in a mice fibromyalgia
model. After 27 days, we evaluated the central nervous system (CNS) pathways involved in
the effect induced by experimental drugs through immunofluorescence protocol to Fos protein.
The differential scanning analysis (DSC), thermogravimetry/derivate thermogravimetry
(TG/DTG) and infrared absorption spectroscopy (FTIR) curves indicated that the products
prepared were able to incorporate the LEO efficiently. Oral treatment with LEO or LEO-βCD,
at all doses tested, produced a significant reduction of mechanical hyperalgesia and we were
able to significantly increase Fos protein expression. Together, our results provide evidence
that LEO, isolated or complexed with β-CD, produces analgesic effects on chronic
non-inflammatory pain as fibromyalgia