Extracts of Pterocarpus osun as a histological stain for collagen fibres

The staining ability of Pterocarpus osun extract on tissue sections was determined. 2 kg of P. osun stem was dried, milled to obtain a fine powder and a red pigment extracted from the powder with 1 L of 70% ethanol at 78°C for 24 h. The alcoholic alkaline and acidic extracts were used to stain tissue sections. Collagen fibres, red blood cells and muscles were stained in shades of reddish brown. Preliminary phytochemical screening of this extract revealed that it contained alkaloids, steroid ring, cardiac glycosides and reducing sugar.