Trichilia monadelpha bark extracts inhibit carrageenan-induced foot-oedema in the 7-day old chick and the oedema associated with adjuvant-induced arthritis in rats

Abstract

Trichilia monadelpha (Thonn) JJ De Wilde (Meliaceae) bark extract is used in African traditional medicine for the management of various disease conditions including inflammatory disorders such as arthritis. The present study was undertaken to evaluate the anti-inflammatory properties of aqueous (TWE), alcoholic (TAE) and petroleum ether extract (TPEE) of T. monadelpha using the 7-day old chick-carrageenan footpad oedema (acute inflammation) and the adjuvant-induced arthritis model in rats (chronic inflammation). TWE and TPEE significantly inhibited the chick-carrageenan footpad oedema with maximal inhibitions of 57.79±3.92 and 63.83±12 respectively, but TAE did not. The reference anti-inflammatory drugs (diclofenac and dexamethasone) inhibited the chick-carrageenan-induced footpad oedema, with maximal inhibitions of 64.92±2.03 and 71.85±15.34 respectively. Furthermore, all the extracts and the reference anti-inflammatory agents (diclofenac, dexamethasone, methotrexate) inhibited the inflammatory oedema associated with adjuvant arthritis with maximal inhibitions of 64.41±5.56, 57.04±8.57, 62.18±2.56%, for TWE, TAE and TPEE respectively and 80.28±5.79, 85.75±2.96, 74.68±3.03% for diclofenac, dexamethasone and methotrexate respectively. Phytochemical screening of the plant bark confirmed the presence of a large array of plant constituents such as alkaloids, glycosides, flavonoids, saponins, steroids, tannins and terpenoids, all of which may be potential sources of phyto-antiinflammatory agents. In conclusion, our work suggests that T. monadelpha is a potential source of antiinflammatory agents.

Keywords: Antiinflammatory; Arthritis; Trichilia monadelpha; chick-carrageenan; phyto-antiinflammatory.

Figure 1

Dose-response effects of diclofenac (10–100 mg kg⁻¹, i.p.) (a and b); and dexamethasone (0.1–1.0 mg kg⁻¹, i.p.) (c and d) on carrageenan-induced foot oedema in chicks. Left panels show the time course of effects and the right panels show the total oedema calculated as area under the time — course curve (AUCs) over the 5 h period. Data is presented as means ± s.e.m (n = 5). ** P < 0.01; *P < 0.05 compared to vehicle-treated group (two-way ANOVA followed by Bonferroni's post hoc test).

Figure 2

Dose-response effects of TWE (10–300 mg kg⁻¹, p.o.) (a and b); TAE (10–300 mg kg⁻¹, p.o.) (c and d) and TPEE (10–300 mg kg⁻¹, p.o.) (e and f) on carrageenan-induced foot oedema in chicks. Left panels show the time course of effects and the right panels show the total oedema calculated as area under the time — course curve (AUCs) over the 5 h period. Data is presented as means ± s.e.m (n = 5). ** P < 0.01; *P < 0.05 compared to vehicle-treated group (two-way ANOVA followed by Bonferroni's post hoc test).

Figure 3

Dose response curves for dexamethasone (0.1–1 mg kg⁻¹ i.p.), diclofenac (10–100 mg kg⁻¹ i.p.), TWE (10–300 mg kg⁻¹ p.o.), TAE (10–300 mg kg⁻¹ p.o.) and TPEE (10–300 mg kg⁻¹ p.o.) on carrageenan induced foot oedema in 7-day old chicks. Animal were treated 1 hour after carrageenan challenge. Each point represents the mean ± s.e.m. (n = 5).

Figure 4

Dose-response effects of dexamethasone (0.1–1 mg kg⁻¹, i.p.) (a and b); diclofenac (10–100 mg kg⁻¹, i.p.) (c and d) and methotrexate (0.1–1 mg kg⁻¹, i.p.) (e and f) on ipsilateral joint thickness in the Adjuvant-induced arthritis. Left panels show the time course of effects and the right panels show the total oedema calculated as area under the time — course curve (AUCs) during the polyarthritic phase (days 10–28). Data is presented as means ± s.e.m (n = 5). *** P < 0.001 ** P < 0.01; *P < 0.05 compared to vehicle-treated group (two-way ANOVA followed by Bonferroni's post hoc test).

Figure 5

Dose-response effects of TWE (30–1000 mg kg⁻¹ p.o.) (a and b); TAE (30–1000 mg kg⁻¹, p.o.) (c and d) and TPEE (30–1000 mg kg⁻¹, p.o.) (e and f) on ipsilateral foot joint thickness in the Adjuvant-induced arthritis. Left panels show the time course of effects and the right panels show the total oedema calculated as area under the time — course curve (AUCs) during the polyarthritic phase (days 10–28). Data is presented as means ± s.e.m (n = 5). *** P < 0.001 ** P < 0.01; *P < 0.05 compared to vehicle-treated group (two-way ANOVA followed by Bonferroni's post hoc test).

Figure 6

Dose response curves (inhibition of oedema) for TWE (10–1000 mg kg⁻¹ p.o.) (●), TAE (10–1000 mg kg⁻¹ p.o.) (○), TPEE (10–1000 mg kg⁻¹ p.o.) (■), dexamethasone (0.1–1 mg kg⁻¹ i.p.) (▲), diclofenac (10–100 mg kg⁻¹ i.p.) (□) and methotrexate (0.1–1 mg kg⁻¹ i.p.) (△) on CFA induced arthritis in rats. Each point represents mean ± s.e.m. (n = 5).