Flora das cangas da Serra dos Carajás, Pará, Brasil: Urticaceae

Ethnopharmacological investigations of the leaves of Cecropia pachystachya Trécul (Urticaceae): A native Brazilian tree species

ETHNOPHARMACOLOGICAL RELEVANCE

Cecropia pachystachya Trécul (Urticaceae) is a medicinal plant popularly known as 'embaúba'. In Brazil, the leaves of this species are used for the treatment of various kidney and cardiovascular diseases. However, there are no detailed studies on the renal and cardiovascular activities of this species. No studies on the anatomy or the quality control of this herbal drug is available thus far.

AIM

This study was aimed to investigate the ethnopharmacological properties of the leaves of C. pachystachya.

MATERIAL AND METHODS

The leaves of C. pachystachya were analyzed by light and scanning electron microscopy for pharmacobotanical and anatomical characterization. The ethanol-soluble fraction of C. pachystachya leaf extract (ESCP) was characterized by high-performance liquid chromatograph equipped with diode array detector and mass spectrometry (HPLC-DAD-MS). The acute oral toxicity of ESCP on female Wistar rats was assessed. The acute and prolonged diuresis and antioxidant effects of ESCP (30, 100, and 300 mg/kg) were evaluated in male Wistar rats. In addition, the hypotensive effects of the ESCP as well as the vasodilatory activity in isolated and perfused mesenteric vascular beds were investigated.

RESULTS

The anatomical markers obtained in this study can help in the identification of C. pachystachya, as well as to distinguish it from the other 'embaúbas'. The metabolites found in the ESCP were phenolic compounds, mainly C- and O-glycosylated flavonoids. The ESCP did not exhibit any toxic effects at a dose of 2000 mg/kg. Significant diuretic activities were observed at the doses of 30, 100, and 300 mg/kg. In addition, a significant modulating activity of the tissue redox state was observed after prolonged treatment. On the other hand, no hypotensive or vasodilator activity was observed.

CONCLUSION

The key findings of the present study can contribute to the taxonomy, species identification and quality control of C. pachystachya. Chemical studies have shown the presence of glycosylated flavonoids, phenylpropanoid derivative and proanthocyanidins. The pharmacological studies showed significant diuretic and antioxidant effects of C. pachystachya leaf extract, indicating a possible validation of its popular medicinal use.

Cangas da Amazônia: a vegetação única de Carajás evidenciada pela lista de fanerógamas

Resumo Nas cangas da Floresta Nacional (FLONA) de Carajás e no Parque Nacional dos Campos Ferruginosos (PNCF) foram registradas 856 espécies, distribuídas em 116 famílias de fanerógamas. As famílias mais ricas foram Poaceae (86), Fabaceae (65) e Rubiaceae (46). O hábito herbáceo foi o melhor representado. Dois gêneros, 24 espécies e uma subespécie são apontadas como endêmicas das cangas da área de estudos. Na FLONA de Carajás, a Serra Norte, com maior amostragem, possui 659 espécies de fanerógamas e na Serra Sul foram registradas 545 espécies. Aproximadamente 60% das espécies documentadas na área de estudos, incluindo espécies endêmicas, não possuem registro para o PNCF. Através da lista taxonômica aqui apresentada, foi possível demonstrar considerável distinção entre as cangas da Serra dos Carajás e as do Quadrilátero Ferrífero, em Minas Gerais, apontando também pouca correspondência dessas duas listas com a canga de Corumbá, no Mato Grosso do Sul. A riqueza e singularidade da flora da região, que inclui diversas espécies endêmicas, associada à ameaça a que estão submetidos estes ambientes por atividades de mineração, apontam para a necessidade de um planejamento para conservação das espécies da flora das cangas de Carajás.