Flavonoids occurring in Vemonia amygdalina leaves have been studied. Three flavones were identified with chemical and spectroscopic techniques. They were identified as luteolin, luteolin 7-0-/3-glucuronoside, and luteolin 7-0-/3-glucoside. The most abundant compound was luteolin 7-0-/3-glucuronoside. The antioxidant activity of the three flavones was determined by measuring the coupled oxidation of /3-carotene and linoleic acid. It was shown that luteolin was a significantly more potent antioxidant than the synthetic antioxidant butylated hydroxytoluene (BHT) at the same concentration (15 mg/L). The two glycosides showed similar activities but significantly lower activities than luteolin or BHT.

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Two new stigmastane-type steroid glycosides, vemoniosides D [l] and E [2], have been isolated from the leaves of Vernonia amygdalina, along with the known vemonioside A3. Vernonioside D [1] was the most abundant glycoside obtained. The chemical structures of 1 and 2 were elucidated using a combination of spectroscopic techniques

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Purpose: To research the antiplasmodial property of aqueous extract, fractions, and residue of Nauclea latifolia roots and to isolate the components responsible for the antiplasmodial activity.Methods: Roots of N. latifolia were macerated with distilled water; the extract was obtained, successively partitioned with ethyl acetate and butanol. The extract, fractions, and the residue obtained were evaluated for their in vivo antiplasmodial activity and compared with amodiaquine and artesunate. The residue (which exhibited the best therapeutic index) was subjected to column and thin layer chromatography to isolate its components. Purification led to the isolation of betulinic acid, which was characterized with the aid of spectroscopic techniques (1H, 13C NMR, and EI-MS).Results: The residue significantly inhibited parasite growth from 42.8 % (D2) to 77.6 % (D5). Therefore, residue exhibited the highest therapeutic index against Plasmodium berghei in the three in vivo antiplasmodial (prophylactic, suppressive, and curative) models and it compared favourably with amodiaquine (80.5 %) and artesunate (85.9 %). The major component of the residue was betulinic acid.Conclusion: The results validate the antiplasmodial claims of the roots of N. latifolia in folkloric medicine, and demonstrated that the isolate has a high therapeutic index in this regard. Further investigations, however, are required to determine the clinical efficacy and safety of the compound/isolate.