The increasing rise of resistance of malaria parasites to established antimalarial drugs have necessitated the continued search for new drug entities especially those with fresh modes of action. Caesalpinia pulcherrima is a plant with many pharmacological and medicinal properties. The leaf extract and fractions were studied for their antimalarial, ferric reducing antioxidant power and elemental composition.Various fractions of the leaf extracts were obtained using vacuum liquid chromatography (VLC). The in vivo antimalarial activity was evaluated against plasmodium berghei parasites. The required dose was given according to the weight of the animal two hours after inoculation of parasites on D1, then once daily for three more days (D2-D4). The antioxidant activity was carried out using UV-Visible spectrometer at 593 nm. The elemental analysis was done using Atomic Absorption Spectrophotometer. There was a dose dependent increase in percentage chemo-suppression of the parasites by the different groups with maximum effect at 800 mg/kg (61.57-34.86 % from day five (5)to day eight (8) respectively). The highest FRAP activity was observed in 100% ethyl acetate with 314.90 ± 3.94 mmol, while the lowest antioxidant power was observed in 50% ethyl acetate:50% n-hexane fraction with 48.50 ± 1.10. 90%methanol:10% distilled water fraction did not indicate any FRAP activity. The results obtained revealed that the phytochemicals with very potent antioxidant power are more present in the ethyl acetate fraction. Elemental compositions (ppm) in the powdered leaf of C. pulcherrima were, sodium (Na); 20.27 ± 0.12, iron (Fe); 13.50 ± 0.08, calcium (Ca); 9.0 ± 0.14, and copper (Cu); 0.30 ± 0.08. Lead (Pb) was not detected. This study has shown that Lead concentration was below detectable limit, while the concentrations of Fe and Cu were within established permissible limits. Appreciable amount of Na and Ca were also indicated. C. pulcherrima leaf extract and fractions contain biologically active principles that are relevant antimalarial and antioxidant agents with acceptable mineral compositions.

Polyalthia longifolia (masquerade tree) is a plant which is believed to possess varied pharmacological and therapeutic values among different populations. The present report investigated the phytochemical composition, proximate, acute toxicity and antioxidant potential of P. longfolia root. All analyses were carried out using established methods; the antioxidant activity of the crude methanol extract and its fractions (n-hexane and ethyl acetate) were examined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay while the total phenolic and flavonoid contents were assessed using the Folin-Ciocalteu and the aluminum chloride calibration methods respectively. The phytochemical analysis revealed the presence of alkaloids, carbohydrate, reducing sugars, tannins, saponins, flavonoids, phenolic compounds and protein in aqueous extract. The proximate analysis showed moisture content, total ash, alcohol extractive value, water extractive value, acid insoluble ash and water soluble ash at 8.80, 9.35, 3.28, 3.29, 2.27 and 7.29% respectively. The ethyl acetate fraction showed the highest antioxidant property compared to the n-hexane fraction and crude methanol extract in all assays conducted. Also, the methanol fraction was found to have the highest flavonoids and phenolic content among the extract and fractions. Oral administration of crude methanol extract of P. longifolia to Swiss mice was relatively non-toxic at a maximum dose of 5000 mg/kg. The root extract and fractions of P. longifolia indicated moderately high level of some phytochemicals with outstanding radical scavenging activity, and therefore substantiate its use as a conventional and comparatively non-toxic plant antioxidant.

Malaria is responsible for about a million deaths yearly. The fight against malaria is faced with the occurrence of widespread resistance of the malaria parasite, Plasmodium spp. The search for plant derived anti-malarial drugs has become greatly imperative. This study was aimed to isolate and investigate the In vivo anti-malarial activity of pulcherrimin A isolated from the stem bark of Caesalpinia pulcherrima. Ethyl acetate fraction of the stem bark extract was subjected to fractionation over silica gel column to obtain pure compound which was characterized as 3,5,6,7tetrahydroxy-19-vouacanoic acid;(3β,5α,6β,7β)-form,6,7-dibenzoyl (pulcherrimin A) a known compound using various spectroscopic techniques. Pulcherrimin A was evaluated for In vivo anti-malarial activity against P. berghe infected mice using the 4-day suppressive test. Different doses (50, 200 and 400 mg/kg/day) of pulcherrimin A were administered to the mice after parasite inoculation. A maximum parasitaemia suppression of 68.18% was observed for the middle dose (200 mg/kg/day) in contrast with 40.91% for the highest dose (400 mg/kg/day). The study therefore revealed that pulcherrimin A isolated from the stem bark of C. pulcherrima exhibited moderate-dose significant (p<0.05) inhibition of P. berghei parasite, thus authenticating the local usage of different parts of the plants in the treatment of malaria and other pyrexia-related infections.

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