Anti – Psoriatic Activity of Psorospermum Febrifugum Stem Bark Extract Using the Rat – Dinitrofluorobenzene Induced Model

Psoriasis has been described as a chronic inflammatory skin disease.  Psorospermum febrifugum is a flowering plant and belong to the family Hypericaceae and found in the tropical areas of the world such as Africa, South America and Madagascar. Alcoholic and aqueous Extracts of P. febrifugum have been reportedly used to treat various skin diseases. This research was therefore conducted to investigate the effectiveness of P. febrifugum stem bark extract against psoriasis. The rat model of psoriasis was developed by induction for 5 days using 100 µL  of 0.5% hapten – 2, 4 – dinitrofluorobenzene in acetone and olive oil in 4:1 ratio. Animals were divided into 5 groups and were administered various doses of the extracts and retinoic acid except the control groups. Animals were also challenged by topical application of 20µL  of 0.2% dinitrofluorobenzene in a mixture of acetone and olive oil to both sides of the ear on days 8, 9 and 10. 400 mg/kg body weight dose significantly reduced psoriatic lesion by 93.15% as against 61.21% by retinoic acid. Ear weight was decreased 54.71% by 200 mg/kg, 71.69% by 400 mg/kg and 69.78% by retinoic acid. The percent inhibitions of ear thickness were 61.76 and 89.71 respectively for 200 and 400 mg/kg body weight of the extract and 63.23 for 0.5 mg/kg of retinoic acid. These results compared to the reported effectiveness of other plant extracts 62 – 65.5% and P. febrifugum with 71 – 93.15%, showed serious indication that P. febrifugum could be effectively used to cure psoriatic conditions.