RESUMO
BACKGROUND: Musa seminifera Lour is a tree-like perennial herb that has been used in folk medicine in Bangladesh to heal a number of ailments. OBJECTIVE: To evaluate the antioxidant, analgesic, antidiarrheal, anthelmintic activities, and general toxicity of the ethanol extract of the roots. MATERIALS AND METHODS: The extract was assessed for free-radical-scavenging activity by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, total phenolic content (TPC) by the Folin Ciocalteu reagent, antioxidant activity by the ferric reducing power assay, analgesic activity by the acetic acid-induced writhing and hot-plate tests, antidiarrheal activity by the castor oil-induced diarrhea model in mice, anthelmintic activity on Paramphistomum cervi and Haemonchus contortus, and general toxicity by the brine shrimp lethality assay. RESULTS: The extract showed free-radical-scavenging activity with an IC50 value of 44.86 µg/mL. TPC was 537.89 mg gallic acid equivalent/100 g of dried plant material. It showed concentration-dependent reducing power, and displayed 42.11 and 69.32% writhing inhibition at doses of 250 and 500 mg/kg body weight, respectively. The extract also significantly raised the pain threshold at the above-mentioned dose levels. In vivo antidiarrheal property was substantiated by significant prolongation of latent period and decrease in total number of stools compared with the control. The LC50 against brine shrimp nauplii was 36.21 µg/mL. The extract exhibited dose-dependent decrease in paralysis and death time of the helminths. CONCLUSION: The above results demonstrated that the plant possesses notable bioactivities and somewhat supports its use in folk medicine.
RESUMO
Arsenic removal by passive treatment, in which naturally present Fe(II) is oxidized by aeration and the forming iron(III) (hydr)oxides precipitate with adsorbed arsenic, is the simplest conceivable water treatment option. However, competing anions and low iron concentrations often require additional iron. Application of Fe(II) instead of the usually applied Fe(III) is shown to be advantageous, as oxidation of Fe(II) by dissolved oxygen causes partial oxidation of As(III) and iron(III) (hydr)oxides formed from Fe(II) have higher sorption capacities. In simulated groundwater (8.2 mM HCO3(-), 2.5 mM Ca2+, 1.6 mM Mg2+, 30 mg/L Si, 3 mg/L P, 500 ppb As(III), or As(V), pH 7.0 +/- 0.1), addition of Fe(II) clearly leads to better As removal than Fe(III). Multiple additions of Fe(II) further improved the removal of As(II). A competitive coprecipitation model that considers As(III) oxidation explains the observed results and allows the estimation of arsenic removal under different conditions. Lowering 500 microg/L As(III) to below 50 microg/L As(tot) in filtered water required > 80 mg/L Fe(III), 50-55 mg/L Fe(II) in one single addition, and 20-25 mg/L in multiple additions. With As(V), 10-12 mg/L Fe(II) and 15-18 mg/L Fe(III) was required. In the absence of Si and P, removal efficiencies for Fe(II) and Fe(III) were similar: 30-40 mg/L was required for As(II), and 2.0-2.5 mg/L was required for As(V). In a field study with 22 tubewells in Bangladesh, passive treatment efficiently removed phosphate, but iron contents were generally too low for efficient arsenic removal.
