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Starch isolated from white yam (Dioscorea rotundata) was subjected to hydroxypropylation under different conditions. Corresponding increases were observed between the molar substitution (MS) and the volume of propylene oxide added to the reaction mixture. After hydroxypropylation, a slight reduction in the intensity of the peak at 2y = 19.67 was observed and the doublet peak at 23.87, which was present in native starch, was no longer seen. Hydroxypropylation enhanced the free swelling capacity (FSC) and solubility. Setback and retrogradation of native starch declined after hydroxypropylation. Turbidity of native starch paste and syneresis were higher with storage time. The results also indicate that enzymatic digestibility improved as the MS increased, while the reverse was observed for starch paste turbidity, syneresis, setback and retrogradation. This study presents relevant information that could strategically position D. rotundata starch and its hydroxypropylated derivatives for industrial applications.

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Antimalarial principles of Spathodeu cumpunulafu stem bark extract were isolated and characterized. The antimalarial principles in the stem bark were 3P-hydroxyurs-12-en-28-oic acid (ursolic acid) and two of its derivatives; 3~hydroxyurs-12,19-dien-28-oic acid (tomentosolic acid) and 3~,2O~-dihydroxyurs-12-en-28 oic acid. This is the first report of the isolation of ursolic acid and its derivatives as antimalarial compounds.

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Hexane, chloroform and methanol extracts of the rootwood and rootbarks of Jatropha podagrica were studied for their antimicrobial activity against 18 organisms. All the extracts exhibited some broad spectrum antibacterial activity, at a concentration of 20 mg/mL. The hexane extracts were generally more active than the chloroform and methanol extracts. The hexane extract of the yellow rootbark was the most active of all the extracts and its activity was comparable to that of gentamycin but better with regard to the control of S. aureus and B. cereus. Three of the extracts, hexane extract of the yellow rootbark and hexane and methanol extracts of the rootwood showed moderate antifungal activity against the yeast fungus, Candida albicans. Copyright © 2000 John Wiley & Sons, Ltd.

The action of extracts of the stem bark of Spathodea campanulata on Pla.smodium berghei berghei in mice has been studied. The blood schizontocidal activity of the extracts was studied in early and established infections using chloroquine as the reference drug. The prophylactic action of the extracts was also investigated with pyrimethamine as the standard drug. The hexane and chloroform extracts of the stem bark showed blood schizontocidal action in both the 4-Day test and Rane test. The chloroform extract demonstrated some prophylactic properties while the aqueous extract did not show any significant antimalarial property. tion of the leaves, the action of the stem bark extracts of the plant was therefore investigated.