Selaginellaceae: traditional use, phytochemistry and pharmacology / Selaginellaceae: uso tradicional, fitoquímica y farmacología

Selaginella is the only genus from Selaginellaceae, and it is considered a key factor in studying evolution. The family managed to survive the many biotic and abiotic pressures during the last 400 million years. The purpose of this review is to provide an up-to-date overview of Selaginella in order to recognize their potential and evaluate future research opportunities. Carbohydrates, pigments, steroids, phenolic derivatives, mainly flavonoids, and alkaloids are the main natural products in Selaginella. A wide spectrum of in vitro and in vivo pharmacological activities, some of them pointed out by folk medicine, has been reported. Future studies should afford valuable new data on better explore the biological potential of the flavonoid amentoflavone and their derivatives as chemical bioactive entities; develop studies about toxicity and, finally, concentrate efforts on elucidate mechanisms of action for biological properties already reported.

Selaginella es el único género de Selaginellaceae, y se considera un factor clave en el estudio de la evolución. La familia logró sobrevivir a las muchas presiones bióticas y abióticas durante los últimos 400 millones de años. El propósito de esta revisión es proporcionar un resumen actualizado de Selaginella para reconocer su potencial y evaluar futuras oportunidades de investigación. Los hidratos de carbono, pigmentos, esteroides, derivados fenólicos, principalmente flavonoides, y alcaloides son los principales productos naturales en Selaginella. Se ha informado un amplio espectro de actividades farmacológicas in vitro e in vivo, algunas de ellas señaladas por la medicina popular. Los estudios futuros deberían proporcionar datos nuevos y valiosos para explorar mejor el potencial biológico de la amentoflavona flavonoide y sus derivados como entidades bioactivas químicas; desarrollar estudios sobre la toxicidad y, finalmente, concentrar los esfuerzos en dilucidar los mecanismos de acción para las propiedades biológicas ya informadas.

In vivo antileishmanial activity and chemical profile of polar extract from Selaginella sellowii

The polar hydroethanolic extract from Selaginella sellowii(SSPHE) has been previously proven active on intracellular amastigotes (in vitro test) and now was tested on hamsters infected with Leishmania (Leishmania) amazonensis (in vivo test). SSPHE suppressed a 100% of the parasite load in the infection site and draining lymph nodes at an intralesional dose of 50 mg/kg/day × 5, which was similar to the results observed in hamsters treated with N-methylglucamine antimonate (Sb) (28 mg/Kg/day × 5). When orally administered, SSPHE (50 mg/kg/day × 20) suppressed 99.2% of the parasite load in infected footpads, while Sb suppressed 98.5%. SSPHE also enhanced the release of nitric oxide through the intralesional route in comparison to Sb. The chemical fingerprint of SSPHE by high-performance liquid chromatography with diode-array detection and tandem mass spectrometry showed the presence of biflavonoids and high molecular weight phenylpropanoid glycosides. These compounds may have a synergistic action in vivo. Histopathological study revealed that the intralesional treatment with SSPHE induced an intense inflammatory infiltrate, composed mainly of mononuclear cells. The present findings reinforce the potential of this natural product as a source of future drug candidates for American cutaneous leishmaniasis.

In vitro activity of the hydroethanolic extract and biflavonoids isolated from Selaginella sellowii on Leishmania (Leishmania) amazonensis

This study is the first phytochemical investigation of Selaginella sellowii and demonstrates the antileishmanial activity of the hydroethanolic extract from this plant (SSHE), as well as of the biflavonoids amentoflavone and robustaflavone, isolated from this species. The effects of these substances were evaluated on intracellular amastigotes of Leishmania (Leishmania) amazonensis, an aetiological agent of American cutaneous leishmaniasis. SSHE was highly active against intracellular amastigotes [the half maximum inhibitory concentration (IC50) = 20.2 µg/mL]. Fractionation of the extract led to the isolation of the two bioflavonoids with the highest activity: amentoflavone, which was about 200 times more active (IC50 = 0.1 μg/mL) and less cytotoxic than SSHE (IC50 = 2.2 and 3 μg/mL, respectively on NIH/3T3 and J774.A1 cells), with a high selectivity index (SI) (22 and 30), robustaflavone, which was also active against L. amazonensis (IC50 = 2.8 µg/mL), but more cytotoxic, with IC50 = 25.5 µg/mL (SI = 9.1) on NIH/3T3 cells and IC50 = 3.1 µg/mL (SI = 1.1) on J774.A1 cells. The production of nitric oxide (NO) was lower in cells treated with amentoflavone (suggesting that NO does not contribute to the leishmanicidal mechanism in this case), while NO release was higher after treatment with robustaflavone. S. sellowii may be a potential source of biflavonoids that could provide promising compounds for the treatment of cutaneous leishmaniasis.

Diuretic effect of alkaloids fraction extracted from Selaginella lepidophylla (Hook. et Grev.) Spring / Efecto diurético de la fracción con contenido de alcaloides extraída deSelaginella lepidophylla (Hook. et Grev.) Spring

The aerial parts of Selaginella lepidophylla (Hook. et Grev.) Spring, are used in Mexican folk medicine to treat renal diseases. The aim of this study was to measure the diuretic response of an aqueous extract (200 mg/kg) and alkaloids fraction at different doses (10, 40 y 100 mg/kg) of this plant and compare it with that induced by furosemide (4 mg/kg). Extract, alkaloids fraction, furosemide and vehicle were administered orally to adult rats and the effects in sodium, potassium and water balance were measured. The extract, the alkaloids fraction and the furosemide produced important and significant increments in urinary excretion of sodium, potassium and water with respect to control group. This increment was dose dependent of the alkaloids fraction, the highest dose produced a major effect. Potassium excretion increased but it was less than the one induced by furosemide. These results suggest that the aqueous extract and rich fraction in alkaloids from S. lepidophylla induce diuretic response.

Las partes aéreas de Selaginella lepidophylla (Hook. et Grev.) Spring, son usadas en la medicina tradicional mexicana para tratar enfermedades renales. El objetivo del estudio fue medir la respuesta diurética de un extracto acuoso (200 mg/kg) y de diferentes dosis de la fracción de alcaloides (10, 40 y 100 mg/kg) de esta planta y compararla con la inducida por furosemida (4 mg/kg). El extracto, la fracción de alcaloides, la furosemida y el vehículo fueron administrados por vía oral a ratas adultas y se midieron los efectos en el balance de sodio, potasio e hídrico. El extracto, la fracción de alcaloides y la furosemida produjeron importantes y significativos incrementos en la excreción urinaria de sodio, potasio y agua con respecto al grupo testigo. Este incremento fue dependiente de la dosis de la fracción de alcaloides, la dosis más alta produjo el mayor efecto. El incremento en la excreción de potasio fue menor al de furosemida. Los resultados sugieren que el extracto acuoso y la fracción rica en alcaloides de S. lepidophylla inducen una respuesta diurética.