Phytochemical Screening and Anti-Inflammatory Properties of the Hydroethanolic Leaf Extract of Calotropis procera (Ait). R. Br. (Apocynaceae)

Aims: Inflammation has been implicated in many disorders and currently available therapies elicit adverse effects. The coarse shrub of Calotropis procera has been used in folk medicine to treat several ailments such as asthma, rheumatism and also fever. The anti-inflammatory potential of Calotropis procera was assessed in this study to evaluate its effectiveness.

Place and Duration of Study: University of Cape Coast, Ghana between June 2016 and March 2017.

Methodology: This study was carried out to screen for the phytochemical constituents and investigate the anti-inflammatory properties of Calotropis procera extract (CPE) using four in vitro assays (heat-induced haemolysis, hypotonic-induced haemolysis, albumin denaturation and the bovine serum albumin assay (BSA)) and, two in vivo models (carrageenan and formalin-induced paw oedema models). Three graded concentrations of the plant extract (CPE) and a standard anti-inflammatory agent, diclofenac: 100, 300 and 1000 μg/mL were used in the in vitro models while 30, 100 and 300 mg/kg were used in the in vivo experiments. Qualitative tests for tannins, alkaloids, flavonoids, carbohydrates, triterpenoids, steroids, proteins, reducing sugars, glycosides, saponins and amino acids were performed to determine the phytochemical constituents of the extract.

Results: The phytochemical screening revealed presence of alkaloids, tannins and triterpenes, reducing sugars, sterols, amino acids, and glycosides. CPE 1000μg/mL demonstrated anti-inflammatory characteristics by significantly stabilizing RBCs exposed to heat and hypotonic solution and also inhibiting protein denaturation in heat-induced denaturation (69.24%); hypotonic-induced (85.09%); albumin denaturation (87.80%) and BSA (96.86% assays). Similar results were observed for the two lower doses of CPE as well as diclofenac. In the in vivo tests, CPE was able to significantly reduce both carrageenan-induced (P=0.0105) and formalin-induced inflammation (P<0.0001) in rats. Diclofenac the reference anti-inflammatory agent also showed similar effects in both tests. The percentage inhibition of paw oedema produced by CPE 30, 100, and 300 mg/kg in the formalin test were 19.61% 35.88% and 47.66% respectively while diclofenac (10 mg/kg) produced 85.16% inhibition of paw oedema.

Conclusion: From the present study, it can be observed that CPE possessed anti-inflammatory properties and thus vindicates the folkloric use of this plant in inflammatory conditions.