Abstract

Lower plants are regarded as unstudied portion of plant kingdom that are not traditionally employed for healing, treatment and management of ailments in folklore medicine. The ethanolic extract of Platycerium angolense, Welwex Hook was phytochemically screenedand analyzed for flavonoid content with a view to investigating its biological activities. The flavonoid fractions were assayed for anti-oxidant, 1, 1, diphenyl-2-pycrilhydrazyl (DPPH) free radical scavenging, anti-inflammatory, inhibition of free radical-induced haemolysis and red blood cell membrane stabilizing activities and the toxicological effects on some biochemical parameters in white albino rats. The results of the present study revealed that phytoconstituents of P. angolense included: saponins, anthraquinones, flavonoids, tannins, deoxysugars and cardiac glycosides. The flavonoid fractions possessed and exhibited appreciable free radical scavenging, anti-oxidant and anti-inflammatory activities. The fractions also inhibited appreciably free-radical induced haemolysis of red blood cells and exerted membrane stability on bovine erythrocytes exposed to both heat and hypotonic- induced lyses. The activities of the fractions were concentrations dependent and compared favourably with those of standard drugs acetaminophen, prednisolone, rutin, and ascorbic acid. Toxicologically, the fractions caused hepatopathy and metabolic derangement in the treated rats. Based on the phytochemicals and biological activities exhibited by the extract of P. angolense and its flavonoid fractions, we conclude that the plant contained potentially useful bioactive molecules with therapeutic activities, and can therefore, be listed as a medicinal plant. However, care must be exercised when the plant is to be used for any form of treatment.

Key words: Platycerium angolense, epiphytes, phytoconstituents, erythrocytes, free-radicals, haemolysis, hepatocytes, scavenging activity.