Total Phenolic Contents and Lipid Peroxidation Potentials of Some Tropical Antimalarial Plants

Abstract

In this investigation extracts of leaves and barks from five tropical antimalarial plants namely; Magnifera indica, Anacardium occidentale, Azachiractha indica, Carica papaya Linn and Cymbopogm citrates were studied in vitro for their total phenolics, total flavonoids and inhibition of lipid peroxidation abilities. Crude extracts from each plant material were obtained by maceration in ethanol and water respectively. The FolinCiocalteu procedure was used to assess the total phenolic concentrations of the extracts and results expressed as gallic acid equivalents (GAE). Total flavonoid contents in extracts were determined by the aluminium chloride colorimetric assay and expressed as quercetin equivalents (QAE). The percentage inhibition of lipid peroxidation was assayed by estimating the thiobarbituric acid-reactive substances (TBARS). The phenolic contents in water extracts of Anacardium occidentale leaves was 452.57 ± 8.08mg/gGAE and that of bark was recorded as 267.15 ± 6.06mg/gGAE. The ethanolic and water extracts of Azachiractha indica bark were found to be 310.71 ± 7.07mg/gGAE and 390.64 ± 6.97mg/gGAE respectively. The extracts of Magnifera indica leaves had the highest flavonoid content of 139.08 ± 0.77mg/100gQAE in ethanol and 69.55 ± 0.39 mg/100gQAE in water. The least values observed were 21.19 ± 0.64 mg/100gQAE for water extract of Anacardium occidentale leaves and 30.73 ± 0.26 mg/100gQAE for ethanolic extract of Anacardium occidentale bark. Inhibition of lipid peroxidation in liver and kidney were observed as 15.92 ± 3.01% and 17.10 ± 3.48% in ethanolic extracts of Anacardium occidentale bark and leaves respectively while it was 30.67 ± 0.47% for Carica papaya Linn. The water extract of Azachiractha indica bark inhibited liver lipid peroxidation by 8.70 ± 0.32% while that of Anacardium occidentale bark inhibited kidney lipid peroxidation by 11.78 ± 1.08%. These results suggest a need for further examination of the water extract of Anacardium occidentale bark as this part of the plant appears to be critical in the phytotherapy of malaria infection.