Effects of aqueous and butanol leaf fractions of olax subscorpioidea oliv. On inflammatory cytokines in wistar rats

Abstract

Olax subscorpioidea leaf is used traditionally in the management of yellow fever, painful swellings, and venereal diseases. Its anti-inflammatory activity has been reported; furthermore, an anti-inflammatory guided fraction of its leaf extract revealed that the aqueous and butanol fractions were the most active. Considering the involvement of cytokines in inflammation, we investigated the effects of the anti-inflammatory activities of the aqueous and butanol leaf fractions on inflammatory cytokines in Wistar rats. Rats were divided into four groups (n = 6) and were orally administered distilled water (1 mL), aqueous/butanol fraction (1,000 mg/kg), and acetylsalicylic acid (ASA, 300 mg/kg). One hour post-treatment, carrageenan (0.1 mL, 1% w/v) was intraperitoneally injected into the right hind paws of the rats. Four hours post inflammation induction, the rats were anesthetized and the hind paws cut-off, homogenized, and centrifuged before collecting the paw exudates. The concentrations of inflammatory cytokines in the exudates were measured. Both fractions significantly (p < 0.05 and p < 0.01) reduced the concentrations of pro-inflammatory cytokines, such as interleukin-1 (IL-1), vascular endothelial growth factor (VEGF), and epidermal growth factor (EGF); and increased the concentrations of anti-inflammatory cytokines such as IL-5, IL-6, and interferon-γ (IFN-γ). The result of the study suggests that the aqueous and butanol leaf fractions of Olax subscorpioidea may be exhibiting their anti-inflammatory activities via the inhibition of pro-inflammatory cytokines such as IL-1, VEGF, and EGF and/or stimulation of the synthesis of anti-inflammatory cytokines such as IL-5, IL-6, and IFN-γ.