Introduction

The use of plants to treat ailments is as old as antiquity. Records of humans using plants to treat diseases have been recorded as far back as 6000 to 4000 years ago when Ayurvedic physicians started treating tumors with extracts from Vinca roseus [₁]. The use of medicinal herb in the treatment and prevention of diseases is attracting attention by scientists world wide [₂]. The use of traditional medicine and medicinal plants in most developing countries, as a normotive basis for the maintenance of good health, has been widely observed [₃].

Anthocleista djalonensis commonly called “Fartanlafla” in Mali [₄], “Osuo” in Bayelsa (Southern Nigeria) is used traditionally for the treatment of various diseases, the plant is known for antipyretic, stomachic, analgesic and purgative actions [₅₆], the aqueous extract was reported to produce a rise in blood pressure of cats and an increase in tone and amplitude of movement of rabbit duodenal preparations. The root decoction has been used in the treatment of diabetes mellitus. Herbalists claim a high percentage of cures in their diabetic patients treated with it [₇].

Traditionally, the leaves are reputed to be used for the treatment of malaria and jaundice [₈]. The bark is used as a purgative in small doses as large doses are considered toxic. According to the Mendi ethnomedicine, when the tree is used as firewood, the people sitting around the fire become sick [₉].

The decoction of the leaves is drunk in Sierra Leone as treatment for jaundice, in Ivory Coast the root is used as a diuretic, vigorous purgative, poison antidote, treatment for leprosy, as an emmenagogue and in the treatment of edemas and elephantiasis of the scrotum. The root decoction is taken against chest pain, constipation and stomach pain [₁₀]. The study was therefore aimed at investigating the anti-inflammatory activity of the leaf extracts with a view to justifying the use of the plant in the treatment of oedemas and elephantiasis of the scrotum.

Materials and Methods

Plant collection and identification

Extraction and fractionation of plant

Phytochemical screening

Drugs and chemicals

Pharmacological evaluation

Determination of Anti-inflammatory Activity

Statistical analysis

Results

Figure 1

Table 1: Effect of methanol extract of on Carrageenan-induced paw edema in Rats

Figure 2

Table 2: Effect of aqueous fraction of the methanol extract of on Carrageenan-induced paw edema in Rats

Figure 3

Table 3: Effect of methanol extract of on Dextran-induced paw edema in Rats

Figure 4

Table 4: Effect of aqueous fraction of the methanol extract of on Dextran-induced paw edema in Rats

Figure 5

Table 5: Phytochemical screening

Discussion

Inflammation is the response of living tissues to injury. It involves a complex array of enzyme activation, mediator release fluid extravasation, cell migration, tissue breakdown and repair [₁₄]. It is also known that anti-inflammatory effects can be elicited by a variety of chemical agents and that there is little correlation between their pharmacological activity and chemical structure [₁₅].This associated with the complexity of the inflammatory process makes the use of different experimental models essential when conducting pharmacological trials.

The present study establishes the anti-inflammatory activity of the methanol extract (crude) of Anthocleista djalonensis and the aqueous fraction of the crude extract in a number of experimental models. Carrageenan induced rat paw edema is a suitable experimental animal model for evaluating the anti-edematous effect of natural products [₁₆] and this is believed to be triphasic, the first phase (1hr after carrageenan challenge) involves the release of serotonin and histamine from mast cells, the second phase (2hr) is provided by kinins and the third phase (3hr) is mediated by prostaglandins, the cycloxygenase products and lipoxygenase products [₁₇]. The metabolites of arachidonic acid formed via the cycloxygenase and lipoxygenase pathways represent two important classes of inflammatory mediators, prostaglandins (products of the cycloxygenase pathway) especially prostaglandin E₂ is known to cause or enhance the cardinal signs of inflammation, similarly, leukotriene B₄ (product of lipoxygenase pathway) is a mediator of leukocyte activation in the inflammatory cascade [₁₈]. From the results, the methanol extract of A. djalonensis leaves inhibited Carrageenan induced rat paw edema at 250 mg/kg and 500 mg/kg, although not significantly different (P> 0.05) from the control (table 1).The aqueous fraction of the methanol extract significantly inhibited (p < 0.05) carrageenan induced rat paw edema, at the third hour the activity of the aqueous fraction is higher than that elicited by Indomethacin in a dose-dependent manner. Indomethacin is a cycloxygenase inhibitor, the methanol extract has activity which is comparable to Indomethacin and can be said to inhibit the cycloxygenase enzyme but lipoxygenase inhibitors also possess significant anti-inflammatory activity against carrageenan induced paw edema [₁₉], so inhibition of carrageenan induced paw edema by the crude extract could also be due to its inhibitory activity on the lipoxygenase enzyme.

Dextran induced edema is a well known experimental model in which the edema is a consequence of liberation of histamine and serotonin from mast cells [₂₀]. At 500 mg/kg the methanol extract significantly inhibited dextran induced rat paw edema (P<0.01) after 60 minutes (table 3). The aqueous fraction also inhibited dextran induced edema significantly (P< 0.05) both at 250 mg/kg and 500 mg/kg after 60 minutes (table 4).

The methanol extract showed a dose dependent activity but was less than that produced by Indomethacin (table 2), the aqueous fraction showed an improved activity as compared to the methanol extract with a maximal effect at 500 mg/kg which was greater than the effect produced by Indomethacin after 60 minutes (table 4).

Preliminary phytochemical screening shows that the extract contains alkaloids, glycosides, saponins and tannins, it has been reported to contain phthalides, xanthones, glucosides and steroids [₂₁].

Conclusion

It can be concluded that both the methanol extract and aqueous fractions of the methanol extract of Anthocleista djalonensis has anti-inflammatory activity against carrageenan and dextran induced paw edema in rats. These activities may be due to their content of tannins, alkaloids, glycosides, saponins and glucosides.

The aqueous fraction of the methanol extract showed better activity profile compared to the methanol extract hence it can be said to possess majority of the activity.

This study demonstrates the efficacy of Anthocleista djalonensis as an anti-inflammatory agent and also scientifically justifies the use of this plant as an anti-edematous agent in folk medicine [₂₂], however, further studies are required to determine the constituents responsible for its anti-inflammatory activity and further authenticate its mechanism of action.

Acknowledgement