RESUMO
The hymenolepiosis by Hymenolepis nana is a major public health problem in developing countries, and the commercial drugs against this parasitosis are not enough effective. The combination of antiparasitic and antioxidant agents has improved the treatment of some parasitoses. Thus, the development of new cestocidal and antioxidant agents to treat the hymenolepiosis cases is important. In the present study, four hydroxy- and four dihydroxy-chalcones were synthesized using the catalyst boron trifluoride diethyl etherate (BF3â¢OEt2). The antioxidant activity and antiparasitic against H. nana of chalcones were tested, as well as the toxicity by the brine shrimp lethality bioassay and the method of Lorke. The antioxidant activity was measured by three radical scavenging assays: 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP). The hydroxyl substitution pattern (number and position), mainly in ring B, was responsible for the chalcone antiparasitic activity. At least one meta or para hydroxyl group in ring B was essential for activity of the synthetic chalcones against H. nana; The time taken for the parasite to die by the 3b and 3e chalcones (20 mg/mL) treatment was up to six times lower than the control drug Praziquantel. On the other hand, chalcones with catechol structure in ring B (3g and 3h) showed the highest antioxidant values. The toxicity evaluations suggests that synthetic hydroxychalcones with cestocidal (3b and 3e) and antioxidant (3g and 3h) activities are safe compounds and potential in vivo agents to treat this parasitosis
Assuntos
Doenças Parasitárias/tratamento farmacológico , Hymenolepis nana/imunologia , Chalconas/administração & dosagem , Antioxidantes/efeitos adversos , Antiparasitários/efeitos adversosRESUMO
Nanchi (Byrsonima crassifolia), arrayan (Psidium sartorianum) and ayale (Crescentia alata) are wild and under-utilized plants from Mexico; their fruits have been used as food and as Mexican traditional remedies against human bacterial infections (e.g. bacillary dysentery). However, scientific reports which support such uses or promote their consumption are scarce. In this work, the antibacterial activities of fruit extracts (i.e. hexanic, HE; chloroformic, CE; and methanolic, ME) were determined by the micro-dilution assay, establishing the Minimum Inhibitory Concentration (MIC) and Minimum Bactericide Concentration (MBC) against 21 human pathogenic bacteria. The HE of arrayan and ayale showed the highest activity against enterobacteria (E. coli, Salmonella spp. and Shigella spp.) (MIC 0.25-2 mg/mL; MBC 0.5-16 mg/mL). The arrayan ME was the most active against the Gram-positive bacteria, showing Staphylococcus aureus the highest sensitivity (MIC 2 mg/mL; MBC 2-4 mg/mL). The presented results support the traditional uses of these plant materials for treating bacterial infectious diseases.
Nanchi (Byrsonima crassifolia), arrayán (Psidium sartorianum) y ayale (Crescentia alata) son plantas silvestres subutilizadas de México; sus frutos son comestibles y usados como medicamentos tradicionales contra infecciones bacterianas humanas (e.g. disentería bacilar). Sin embargo, los reportes científicos que avalen los usos y promuevan su consumo son escasos. En este trabajo se determinó, ensayo de micro-dilución en caldo, la Concentración Mínima Inhibitoria (CMI) y Concentración Mínima Bactericida (CMB), de los extractos de frutos (hexánico, EH; clorofórmico, EC; y metanólico, EM) contra 21 bacterias patógenas humanas. Los EH de arrayán y ayale mostraron la mayor actividad (CMI 0.25-2 mg/mL; CMB 0.5-16 mg/mL) contra enterobacterias (Escherichia coli, Salmonella spp. y Shigella spp.). El EM de arrayán fue el más activo contra bacterias Gram positivas, presentando Staphylococcus aureus la mayor sensibilidad (CMI 2 mg/mL; CMB 2-4 mg/mL). Estos resultados apoyan el uso tradicional de estos materiales en padecimientos asociados al tratamiento de infecciones bacterianas.