Evaluation of Natural Products

Crude extracts from Warburgia ugandensis Sprague, Azadirachta indica, Tagetes minuta and Urtica massaica have been tested against soil pathogens; Fusarium oxysporum, Alternaria passiflorae and Aspergillus niger. The results obtained showed biological activity against these pathogens except for U. massaica extract, which was not active. Separation of the crude extract from W. ugandensis yielded two pure compounds; Muzigadial and Muzigadiolide whose structures were confirmed by spectroscopic techniques and comparing with already existing spectroscopic data. The minimum inhibitory concentration (MIC) for those two compounds from W. ugandensis have been obtained. Green house experiments using W. ugandensis crude extract against F. oxysporium that causes wilting in Lycopersicon esculentum (tomato plant) have been carried out. Data interpretation carried out by Analysis of variance and comparison of various treatments through LSD and DMRT tests showed that this crude extract controlled the pathogen F. oxysporum. INTRODUCTION Methyl bromide has been used as a fumigant for over 60 years. An important valuable property of methyl bromide is the broad range of pests that it can control. It is used as a fumigant against pathogens (fungi, bacteria and soil borne viruses), insects, mites, nematodes and rodents. These pests may be in the soil, in durable or perishable commodities, as in structures and transportation vehicles. The broad spectrum of activity and ease of application of the material have led to its use as treatment of choice in a number of situations. Several agricultural systems involving intensive production of high value crops have become dependent on the use of methyl bromide. On a global basis, the largest single use of methyl bromide is as a soil fumigant (1).