Plant species used in giardiasis treatment: ethnopharmacology and in vitro evaluation of anti-Giardia activity

The aim of this study was to compile the traditional knowledge about plants used for the treatment of giardiasis, and also to carry out experimental research to evaluate the anti-Giardia activity of five species.To reach this objective, 398 interviews were performed using a previously prepared questionnaire, followed by an in vitro evaluation of giardicidal potential of hydroalcoholic leaf extracts of Anacardium occidentale L., Chenopodium ambrosioides L., Passiflora edulis Sims, Psidium guajava L., and Stachytarpheta cayennensis (Rich.) Vahl. Among the interviewed people, 55.53% reported the use of plants to treat diarrhea, the most severe symptom of giardiasis. The results indicated 36 species used by this population for these problems. The use of leaves (72.50%) of a single plant (64.25%) collected from backyards and gardens (44.34%) and prepared by decoction were predominant. The majority of the interviewees (85.52%) attributed their cure to the use of plants. In the experimental tests, all extracts inhibited the growth of Giardia lamblia trophozoites in different intensities: A. occidentale and P. guajava extracts elicited a moderate activity (250 ≤ IC50 ≤ 500 μg/ml), C. ambrosioides and S. cayennensis extracts evoked a high activity (100 ≤ IC50 ≤ 250 μg/ml), and P. edulis extract showed very high activity (IC50 ≤ 100 μg/ml). This study shows that an ethnopharmacological approach is useful in the selection of plant materials with potential giardicidal activity.

Avaliação da atividade leishmanicida in vitro de plantas medicinais / Evaluation of the in vitro leishmanicidal activity of medicinal plants

Na busca de novos agentes leishmanicidas, avaliamos em culturas de promastigotas de Leishmania amazonensis o efeito dos extratos hidroalcoólicos das folhas de Tephrosia cinerea (L.) Pers. (Fabaceae), Dichorisandra sp (Commelinaceae), Syzygium jambolanum DC. (Myrtaceae), Julocroton triqueter (Lam.) Didr. var. triqueter (Euphorbiaceae), Passiflora edulis Sims(Passifloraceae), Cecropia sp (Cecropiaceae), Chenopodium ambrosioides L.(Chenopodiaceae), Pedilanhus tithymaloides (L.) Poit (Euphorbiaceae), Peristrophe angustifolia Nees(Acanthaceae) e o extrato aquoso do mesocarpo de Orbignya phalerata Mart. (Arecaceae). As promastigotas de Leishmania amazonensis foram cultivadas em presença de 31,3; 63,5; 125,0; 250,0 e 500,0 µg/mL dos extratos por 24 horas. Ao final desse período foi calculada a concentração inibitória do crescimento (CI50) em relação às culturas não tratadas com os extratos. Os extratos das espécies J. triqueter, Dichorisandra sp e T. cinerea apresentaram maior eficácia em induzir a morte das promastigotas, com CI50 de 29,5; 32,9 e 43,6 µg/mL, respectivamente. P. edulis, C. ambrosioides e S. jambolanum apresentaram eficácia moderada com CI50 de 150,1; 151,9 e 166,6 µg/mL, respectivamente. P. tithymaloides e O. phalerata apresentaram baixo efeito leishmanicida com CI50 >500 µg/mL, enquanto Peristrophe angustifolia e Cecropia spnão apresentaram efeito. Dessa forma, dos dez extratos testados, três apresentaram uma expressiva atividade leishmanicida in vitro.

Searching for new leishmanicidal agents, promastigotes forms of L. amazonensis were cultured with the hydroalcoholic extracts obtained from the Tephrosia cinerea (L.) Pers. (Fabaceae), Dichorisandra sp (Commelinaceae), Syzygium jambolanum DC. (Myrtaceae), Julocroton triqueter (Lam.) Didr. var. triqueter (Euphorbiaceae), Passiflora edulis Sims(Passifloraceae), Cecropia sp (Cecropiaceae), Chenopodium ambrosioides L.(Chenopodiaceae), Pedilanhus tithymaloides (L.) Poit (Euphorbiaceae), Peristrophe angustifolia Nees(Acanthaceae) leaves and the aqueous extract obtained from the Orbignya phalerata Mart. (Arecaceae) mesocarp flour. The in vitro assay was performed with promastigotes incubated during 24 hours with 31.3, 62.5, 125.0, 250.0 and 500.0 µg/mL of each extract. Then the inhibitory concentration of the parasite growth (IC50) was determined. The effectiveness of J. triqueter, Dichorisandra sp and T. cinerea hydroalcoholic extracts to induce promastigotes death was intense since the IC50 were 29.5; 32.9 and 43.6 µg/mL, respectively. P. edulis, C. ambrosioides and S. jambolanum extracts had moderated effectiveness since the IC50 were 150.1; 151.9 and 166.6 µg/mL, respectively. P. tithymaloides and O. phalerata extracts showed a low efficacy in comparison with IC50 >500 µg/mL. Peristrophe angustifolia and Cecropia sp extracts had no leishmanicidal effect. Thus, three of the ten extracts that were tested showed a significant in vitro leishmanicidal activity.

Plants and chemical constituents with giardicidal activity / Plantas e constituintes químicos com atividade giardicida

Intestinal infection caused by Giardia lamblia represents a serious public health problem, with increased rates of prevalence in numerous countries. Increased resistance of the parasite and the side-effects of the reference drugs employed in the treatment of giardiasis make necessary to seek new therapeutic agents. Natural products, especially of plant origin, represent excellent starting point for research. The objective of this study is to review the literature on plant extracts, fractions and chemical constituents whose giardicidal activity has been investigated in vitro. The review describes 153 (one hundred and fifty-three) plant species from 69 (sixty-nine) families that were evaluated for their giardicidal activity. The geographical distribution of the plant species, the part used, preparation, strain of Giardia lamblia tested and the results obtained by the authors are also given. One hundred and one compounds isolated from plant species, classified by chemical class, are presented. Recent aspects of research on natural products of plant origin employed in the treatment of giardiasis are also discussed.

Infecção intestinal causada por Giardia lamblia representa grave problema de saúde pública, com elevadas taxas de prevalência em diversos países. O aumento de resistência do parasita e os efeitos colaterais dos fármacos de referência empregados no tratamento da giardíase, tornam necessário a busca de novos agentes terapêuticos. Produtos naturais, especialmente de origem vegetal, representam excelentes fontes de pesquisas. Este trabalho tem como objetivo revisar a literatura de extratos de plantas, frações e compostos químicos com estudos in vitro de avaliação da atividade giardicida. A revisão refere 153 (cento e cinqüenta e três) espécies vegetais de 69 (sessenta e nove) famílias que foram submetidas à avaliação da atividade giardicida. Descreve a distribuição geográfica das espécies vegetais, parte usada, preparação, cepa de Giardia lamblia testada e resultados por autores. Apresenta 101 (cento e um) compostos isolados de espécies vegetais classificados por classes químicas. Discute aspectos recentes da pesquisa de produtos naturais de origem vegetal empregados no tratamento da giardíase.