Bioactivity-guided evaluation of the root extract of Plumbago zeylanica

The haemagglutination, free radical scavenging and membrane stabilizing activities of combined ethyl acetate/diethylether extract of root of Plumbago zeylanica were investigated. The combined fraction (ethyl acetate/diethylether) was chromatographed on silica gel column using hexane/ethyl acetate gradient elution (100:0 – 0:100 v/v) to afford seven fractions (A-F) based on Rf values and phytochemical evaluation tests. The fractions were assayed for phytochemical constituents, total phenol contents, free radical scavenging and membrane stabilizing activities and toxicity using haemaglutination assay method. The phytoconstituents include anthraquinones, flavonoids and phenolic acids. The phenolic contents in the fractions ranged between 0.27 ± 0.04 and 0.93 ± 0.28 mg/g tannic acid equivalent (TAE). The fractions exhibited strong and appreciable free radical scavenging and membrane stabilizing activities and agglutinated red blood cells, which implied toxicity. These activities compared favourably with standard anti-inflammatory and anti-oxidant drugs. The results revealed that while some of the fractions haemaglutinated red blood cells, others provided effective antioxidant and anti-inflammatory activities