In vitro evaluation of traditionally used Surinamese medicinal plants for their potential anti-leishmanial efficacy.

ETHNOPHARMACOLOGICAL RELEVANCE: Plant-based preparations are extensively used in Surinamese folk medicine for treating leishmaniasis, but often without a scientific rationale. AIM OF THE STUDY: To evaluate 25 Surinamese medicinal plants for their potential efficacy against leishmaniasis. MATERIALS AND METHODS: Concentrated plant extracts were evaluated for their effect on the viability of L. (V.) guyanensis AMC, L. (L.) major NADIM5, and L. (L.) donovani GEDII promastigotes, as well as intracellular amastigotes of L. (L.) donovani BHU814 in infected THP-1 cells. Selectivity was assessed by cytotoxicity against THP-1 cells. RESULTS: The only plant extract that showed potentially meaningful anti-leishmanial activity was that from Solanum lycocarpum that displayed mean IC50 values of about 51, 61, and <16 µg/mL against L. (V) guyanensis, L. (L) major, and L. (L) donovani promastigotes, respectively; about 374 µg/mL against L. (L) donovani amastigotes; and >500 µg/mL against THP-1 cells. The Bryophyllum pinnatum, Inga alba, and Quassia amara extracts displayed moderate to high IC50 values against promastigotes (about 51 to >500 µg/mL) and/or amastigotes (about 224 to >500 µg/mL) but were relatively toxic to THP-1 cells (IC50 values <16 to about 42 µg/mL). The remaining plant extracts exhibited in many cases IC50 values close to, around, or above 500µg/mL against promastigotes, amastigotes, and THP-1 cells. CONCLUSIONS: The S. lycocarpum preparation may be useful against leishmaniasis and may have a good safety index, warranting further investigations into its active constituents and mechanism(s) of action.

Evaluation of Surinamese medicinal plants for their effects on the contractility of hypoxic guinea pig myocardial tissue

OBJECTIVE: Cardiac stunning occurs after a transient hypoxic or ischemic insult. Preparations from Anona muricata L., Bixa orelana L., Cecropia palmata Willd., Erythrina fusca Lour., Hibiscus esculentus L., Psidium guajava L., and Terminalia catappa L. were evaluated for their possible positive-inotropic effects in a laboratory model of cardiac stunning. DESIGN AND METHOD: Thus, isolated guinea pig atria perfused in oxygenated Ringer-Locke buffer, were exposed to 5-min periods of hypoxic stress and then allowed to recover for 2 x 3 min in oxygenated buffer alone or supplemented with norepinephrine (10-5 M) or a plant extract (0.001 – 1 mg/mL). Atrial contraction force (F) was measured with a force transducer and contractility was derived by calculation of dF/dt. Troponin C - a highly specific marker for heart muscle cell death - was measured in the perfusion solution in the absence or presence of the plant extracts. RESULTS: Reoxygenation led to a gradual recovery of the atria, but they remained in a state of depressed contractility for at least 4 min. However, exposure to the A. muricata, B. orellana, C. palmata, and T. catappa extracts increased the contractility by 50 to 250%. Notably, troponin C release was 3- to 6-fold higher in incubations with the two latter preparations. CONCLUSION: Preparations from A. muricata, B. orellana, C. palmata, and T. catappa may possess positive-inotropic properties that may be useful in cardiac stunning. However, those from C. palmata and T. catappa may cause myocardial damage that may limit their usefulness in this condition.

Cytotoxic and genotoxic effects of commonly used surinamese medicinal plants in cultured Chinese hamster ovary cells

OBJECTIVE: Medicinal plants are popularly used in Suriname for treating a wide variety of conditions. However, there are often no records about their possible adverse maternal and perinatal effects. For this reason, we assessed a number of commonly used plant-derived folk medicines for their potential genotoxic effects in a cell culture model. DESIGN AND METHODS: Parts from Aloe vera, Apium graveolens, Azaradichta indica, Carica papaya, Cocos nucifera, Dioscorea villosa, Eryngium foetidum, Gossypium barbadense, Momordica charantia, Musa x paradisiaca, and Senna reticulata were extracted with distilled water, freeze-dried, and stored at -20oC. Next, they were evaluated at serial dilutions for their effects on the proliferation of, and DNA damage formation in cultured Chinese hamster ovary (CHO) cells using a sulforhodamine B and a single cell gel electrophoresis (comet) assay, respectively. The latter studies were validated by assessing the DNA strand-breakage induced by etoposide. RESULTS: The extracts from A. vera, G. barbadense, M. charantia, M. paradisiaca, and S. reticulata inhibited cell growth at IC50 values of 100 to 400 μg/mL, whereas the remaining samples were hardly cytotoxic (IC50 values > 1,000 μg/mL). However, only the extracts from G. barbadense and M. paradisiaca caused appreciable DNA damage, viz. 40 and 30%, respectively. CONCLUSIONS: Preparations from G. barbadense and M. paradisiaca should be used with caution, particularly by pregnant women. These samples are now further evaluated in more comprehensive models of genotoxicity.