Bioactivity Guided Isolation and Characterisation of Acaricidal Principles of Plumbago Zeylanica L. (Plumbaginaceae)

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This thesis is a report on the bioactivity guided isolation and characterisation of acaricidal principles of Plumbago zeylanica L. (Plumbaginaceae) a shrubby plant found in the coastal areas of Ghana. Plumbago zeylanica is known throughout the tropics and the sub-tropics and used to treat parasitic skin infections and piles. It is also used to treat worm infestation and as an abortifacient. The study has shown that the roots of P. zeylanica exhibit acaricidal properties in vitro.Preliminary bioactivity studies of the crude methanolic extract showed activity on tick larvae. An ethyl acetate fraction that was made from the crude extract also showed activity on the ticks while the aqueous fraction left after the extraction with the ethyl acetate had no activity. Preliminary TLC analysis of the ethyl acetate fraction showed five constituents all of which were isolated by column chromatography and tested for their activities on ticks. The major constituent, plumbagin was found to be the most active against the ticks. Two other constituents which were identified as β- sitosterol and stigmasterol, were found to be weakly active. Comparison of the chemical profiles of the root, stem and leaf revealed the occurrence of plumbagin in the different organs of the plant but most in the root (2.00% w/w) and least in the leaf (0.028% w/w).
A thesis submitted to the Board of Postgraduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi, in partial fulfilment of the requirement for the award of the Degree of Master of Philosophy, 1998