In vivo Chemosuppressive effects of Combinations of Three Nigerian Ethnomedicinal Antimalarial Plants

Aims: Appropriate ratios for combining some African ethnomedicinal plants with proven anti-plasmodial activity were determined with the aim of obtaining herbal remedies with higher efficacies. Place and Duration of the Study: Study was conducted in the Department of Pharmacognosy, Obafemi Awolowo University, Ile-Ife Nigeria. Study Design: Infusions of dried powders of three Nigerian ethnomedicinal plants, Eugenia uniflora leaf, Gongronema latifolium root and stem and Artocarpus altilis stem bark, were separately evaluated and in varied combination ratios for their anti-plasmodial activities Methodology: The infusions were separately prepared, concentrated in vacuo, freeze-dried and evaluated at 400mg/kg against Plasmodium berghei berghei parasites, using the Peter’s four-day chemosuppressive mice model. Normal saline and chloroquine (10mg/kg) were negative and positive controls, respectively. 2- and 3-combinations of the infusions were similarly tested. Results: Of the 2-plant combination ratios, 1:1, 1:3, 2:3 of EG and GA elicited percentage chemo suppressions which were comparable (P=.28; P=.07) to those of the single drugs. Only the EG ratios gave activities that were comparable (P=.28) to the positive control in addition to double survival times and high survivor values by EG 2:3 and GA 1:3. However, those of the EA group, gave relatively low values, barely above 20% with only the ratios 2:3 and 3:2 giving values which were significantly (P=.00) higher than negative control with double survival times. The 3-plant combination ratios, EGA 2:1:2 and 3:3:2 gave suppressions that were significantly (P=.00) higher than the negative control with others but comparable (P=.33) activities to those of the individual drugs. The other ratios with low suppression values were relatively inactive. But three ratios, EGA 3:1:2, 2:1:1, 1:1:1 elicited survival times doubled (204, 242 and 202 %) that of the negative control without commensurate high antiplasmodial activities. Conclusion: Ethnomedicinal antimalarial plants should not be combined without a data of previous scientific evaluations.

In vitro antimalarial activity of extracts of some plants from a biological reserve in Costa Rica

Treatment with the usual antimalarial drugs, have induced parasite resistance, reinforcing the need to finding natural antimalarial components that would be found on plants from the forest. Therefore, we decided to look for these components in Costa Rican plants from a protected forest area. Fresh and dry extracts of roots, bark, leaves, flowers and fruits of 25 plants from a biological reserve in Costa Rica, Reserva Biológica Alberto Manuel Brenes (REBAMB), were studied in vitro for the presence of substances with antimalarial activity. By studying the inhibition of P. berghei schizogony, we assessed the antimalarial activity of several plant extracts: Aphelandra aurantiaca, A. tridentata (Acanthaceae); Xanthosoma undipes (Araceae); Iriartea deltoidea (Arecaceae); Neurolaena lobata (Asteraceae); Senna papillosa, Pterocarpus hayessi, Lonchocarpus pentaphyllus (Fabaceae); Nectandra membranacea, Persea povedae, Cinamomum chavarrianum (Lauraceae); Hampea appendiculata (Malvaceae); Ruagea glabra, Guarea glabra (Meliaceae); Psidium guajava (Myrtaceae); Bocconia frutescens (Papaveraceae); Piper friedrichsthalii (Piperaceae); Clematis dioica (Ranunculaceae); Prunus annularis (Rosaceae); Siparuna thecaphora (Siparunaceae); Solanum arboreum, Witheringia solanácea (Solanaceae); Ticodendrum incognitum (Ticodendraceae); Heliocarpus appendiculatus (Tiliaceae) and Myriocarpa longipes (Urticaceae). We used different parts of the plants as well as fresh and dried extracts for testing IC50. The solid content of the extracts ranged from 1-71.9μg/mL. The fresh extracts showed stronger activity than the dry ones. Since the plants showing the strongest antimalarial activity are very common in Central America, and some similar genera of these plants have shown positives results in South America, we considered important to present these findings for discussion. On the other hand, this is the first systematic study of this kind ever realized in a circumscribed and protected area of Costa Rica. Rev. Biol. Trop. 60 (2): 881-891. Epub 2012 June 01.

El tratamiento con las drogas antimaláricas de uso común han inducido resistencia por parte del parásito, lo que obliga a buscar en las plantas de los bosques, componentes naturales con actividad en contra de esta enfermedad. Por lo tanto, decidimos buscar dichos componentes en plantas de una Reserva Forestal de Costa Rica. Extractos tanto frescos como secos de raíz, corteza, hojas, flores y frutos, de 25 plantas de la Reserva Biológica Alberto Manuel Brenes (REBAMB), fueron estudiados in vitro en busca de sustancias con actividad antimalárica. Las plantas estudiadas fueron: Aphelandra aurantiaca, A. tridentata (Acanthaceae); Xanthosoma undipes (Araceae); Iriartea deltoidea (Arecaceae); Neurolaena lobata (Asteraceae); Senna papillosa, Pterocarpus hayessi, Lonchocarpus pentaphyllus (Fabaceae); Nectandra membranacea, Persea povedae, Cinamomum chavarrianum (Lauraceae); Hampea appendiculata (Malvaceae); Ruagea glabra, Guarea glabra (Meliaceae); Psidium guajava (Myrtaceae); Bocconia frutescens (Papaveraceae); Piper friedrichsthalii (Piperaceae); Clematis dioica (Ranunculaceae); Prunus annularis (Rosaceae); Siparuna thecaphora (Siparunaceae); Solanum arboreum, Witheringia solanacea (Solanaceae); Ticodendrum incognitum (Ticodendraceae); Heliocarpus appendiculatus (Tiliaceae) y Myriocarpa longipes (Urticaceae). Los extractos frescos y secos de las diferentes partes de las plantas fueron estudiadas y se determinó la IC50, el cual osciló entre 1-71.9mg/mL; los extractos frescos mostraron mayor actividad antimalárica. Las plantas que presentaron mayor actividad son muy comunes en Centroamérica y algunos géneros similares, aunque no las mismas especies, han sido encontrados positivos en América del Sur; por esta razón consideramos importante estos resultados como información y materia de discusión en este tema. Además este es el primer estudio sistemático de esta naturaleza realizado en un área boscosa circunscrita y protegida de Costa Rica.

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

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.