Abstract:
Background: Clerodendrum petasites, an herbal plant in Thailand, has been used for many years in folk
medicine. However, scientific evidence regarding CNS safety pharmacology and antinociceptive activity
of C. petasites (CP) has not yet been well characterized.
Purpose: The present study aimed to assess the CNS safety pharmacology and antinociceptive and
antiinflammatory effects of CP extract.
Methods: The effect of CP extract on CNS safety pharmacology was assessed using LABORAS automated
home cage monitoring and rotarod test. Its pharmacological activity was evaluated both in-vitro, and in vivo using hot-plate, acetic acid-induced writhing, formalin, and carrageenan-induced paw edema
models.
Results and conclusion: CP extract significantly improved thermal and chemical nociceptive behaviors
and acute inflammatory pain at all doses: 300, 600, and 1200 mg/kg, p.o. The antiinflammatory effect of
CP extract in inflammatory pain models was comparable to the effect of positive control: indomethacin
10 mg/kg at all dose levels tested. Further, the CP extract at 600 mg/kg dose significantly inhibited 82.3%
of carrageenan-induced total edema. In-vitro, CP extract at 12.5, 25, and 50 mg/mL concentrations
significantly reduced the expression of LPS-induced nitric oxide, IL-6, and TNF-a expression in both RAW
264.7 macrophage and BV-2 microglial cell lines. In addition, CP extract did not show any potential ef fects on the CNS, indicated by no significant effects on motor coordination, spontaneous locomotor ac tivity, general behaviors, and well-being compared to vehicle-treated mice (p > 0.05). Overall, the
present study evidences the potential antinociceptive, antiinflammatory efficacies of CP extract with a
favorable CNS safety profile.
