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This study sought to have an insight into the mechanism of action of diseases responsible for the susceptible Codiaeum variegatum (garden croton) leaves induced by Fusarium species and the clinical importance of the d isease resistant types. The plants were obtained fro m the Babcock University Germp lasm Repository. Therefore, phytopathogenic Fusarium species were isolated fro m three diseased susceptible cult ivars of C. variegatum (ovalifolium, royal-like and punctatum). Accordingly, lect in was isolated, purified and characterized fro m the leaves of a resistant garden croton cultivar (royal), and further evaluated for antifungal act ivity using isolates of Fusarium lateritium and F. semitectum obtained fro m the three diseased cultivars. The heamagglutinating activity of the purified lect in was non selective to type of blood group (A, B, A B and O) and was inhib ited by fructose, sialic acid, and copper sulphate, but was enhanced by galactose, calciu m chloride, sodium chloride and magnesium chloride. Optimu m heamagglutinating activ ity of the lectin was achieved at 30-40℃ and pH 5.0-6.0. The lectin exh ibited antifungal activity against the two Fusarium species in a non-concentration dependent manner. It is therefore concluded that Fusarium species are major phytopathogens of the garden croton plant and their spectrum of pathogenicity is dependent on the presence or absence of lectins. In addition, the resistant cultivar of C. variegatum (cv. royal) used in this study may be a suitable candidate for the prevention and treatment of fungal infections.

In the course of their evolution, plant developed chemical defences when attacked. These phytochemicals inadvertently protect humans against pathogens as antimicrobial medicines. Thus, six clone cultivars of Codiaeum variegatum (Spirale, Royal, Broad Spotted Guinea, Punctatum, Sunray and Royal-like) were chemically and cytologically investigated to evaluate their therapeutic potentials, values and variability. The shoots were relatively rich in alkaloids, cardiac glycosides, saponins, tannins, cardenolides, steroids, and phyllates. Flavonoids, phlobatannins, phenols and anthraquinones were sparingly present. Anthraquinones and cardenolides were absent in 'Spirale' while 'Sunray' lacked tannins, phlobatannins and phenols. Terpenes were found only in 'Sunray'. Overall, alkaloids were the most abundant with the highest mean value of 1.46% in 'Royal' while flavonoids and anthraquinones were trace, 0.002 and 0.003%, in 'Sunray' and 'Royal-like'. Five pigments, carotene (yellow-orange), phaeophytin (grey), chlorophyll a (blue-green) and b (green), and xanthophyll (yellow) were determined. 'Spirale', 'Royal', 'Broad Spotted Guinea' and 'Punctatum' had diploid chromosme number of 2n = 60 while 'Sunray' and 'Royal-like' possessed 2n = 30 and 24 respectively. 'Spirale' and 'Sunray' appeared to have reasonably diverged from the rest. Genetic mutation and chromosomes variability could account for the wide morphological variation and morphotypes in this plant species.

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