Hydroethanolic extract from Echinodorus scaber Rataj leaves inhibits inflammation in ovalbumin-induced allergic asthma.
BACKGROUND
Echinodorus scaber, Alismataceae, is popularly known in Brazil as "chapéu-de-couro". The plant leaves are used by the population as decoction, infusion, or maceration in bottled spirits, to treat inflammatory respiratory diseases.


OBJECTIVE
To investigate the anti-inflammatory mechanism of the hydroethanolic extract of leaves of Echinodorus scaber (HEEs) in allergic asthma. A phytochemical analysis of the extract was performed as well.


METHODS
The leaves of Echinodorus scaber were prepared by maceration in 75% ethanol. Preliminary phytochemical analysis was carried out using basic classical methods, and the secondary metabolites detected in HEEs were analyzed and confirmed by high-performance liquid chromatography (HPLC). The in vivo anti-inflammatory activity of HEEs was evaluated in Swiss male albino mice sensitized and challenged by OVA. The HEEs (1, 5 and 30mg/kg, p.o.) was administered to mice twice a day, 1h before the challenge, from days 19 through 24. The mechanism of action of HEEs was studied by evaluating the levels of TH2 cytokines (IL-4, IL-5 and IL-13) in bronchoalveolar lavage fluid (BALF) and IgE production in blood plasma. Histopathological changes triggered by OVA-sensitization/challenge in the lung tissue were also investigated.


RESULTS
HEEs reduced total leukocyte, eosinophil, neutrophil, and mononuclear cell counts at all doses tested, with maximum effect at 30mg/kg (73.9%, 75.9%, 75.5%, and 65.2% reduction, p<0.001, respectively). Increases in TH2 cytokine secretion (IL-4, IL-5 and IL-13) and in IgE levels were also attenuated by HEEs. Preliminary phytochemical screening seems to indicated the presence of phenolic compounds, flavonoids and alkaloids. HPLC analyses evidenced the presence of phenolic compounds, such as gallic acid, rutin and vitexin.


CONCLUSIONS
Our findings provided pharmacological preclinical evidence for the popular use of the leaves of Echinodorus scaber in allergic inflammation. Its anti-inflammatory effect was dependent on the decrease in migratory inflammatory cells, and both TH2 cytokines and IgE levels. It is suggested that vitexin, gallic acid and rutin, known anti-inflammatory compounds, may participate in the anti-asthamtic effect of the HEEs, by acting jointly along with other components present in the extract.
Pharmacology Area, Department of Basic Sciences in Health, Faculty of Medicine, Federal University of Mato Grosso, UFMT, 78060-900 Cuiabá, MT, Brazil.
Suellen Iara Guirra
SIG
Rosa
Physiology Area, Department of Basic Sciences in Health, Faculty of Medicine, Federal University of Mato Grosso, UFMT, 78060-900 Cuiabá, MT, Brazil.
Fabrício
F
Rios-Santos
Pharmacology Area, Department of Basic Sciences in Health, Faculty of Medicine, Federal University of Mato Grosso, UFMT, 78060-900 Cuiabá, MT, Brazil; Pharmacy Graduation Curse, Faculty of the Northwest of Mato Grosso, Juína Association of Higher Education, AJES, 78320-000 Juína, MT, Brazil.
Sikiru Olaitan
SO
Balogun
Pharmacology Area, Department of Basic Sciences in Health, Faculty of Medicine, Federal University of Mato Grosso, UFMT, 78060-900 Cuiabá, MT, Brazil.
Danielle Ayr Tavares
DAT
de Almeida
Histology and Cell Biology Area, Department of Basic Sciences in Health, Faculty of Medicine, Federal University of Mato Grosso, UFMT, 78060-900 Cuiabá, MT, Brazil.
Amilcar Sabino
AS
Damazo
Pharmacology Area, Department of Basic Sciences in Health, Faculty of Medicine, Federal University of Mato Grosso, UFMT, 78060-900 Cuiabá, MT, Brazil.
Thais Campos Dias
TCD
da Cruz
Pharmacology Area, Department of Basic Sciences in Health, Faculty of Medicine, Federal University of Mato Grosso, UFMT, 78060-900 Cuiabá, MT, Brazil.
Eduarda
E
Pavan
Laboratory of Natural Research Products, Faculty of Medicine, Federal University of Tocantins, UFT, 77020-210 Palmas, TO, Brazil.
Robson Dos Santos
RDS
Barbosa
Post-Graduate Studies in Agroenergy, Federal University of Tocantins, UFT, 77020-210 Palmas, TO, Brazil.
Tarso da Costa
TDC
Alvim
Laboratory of Natural Research Products, Faculty of Medicine, Federal University of Tocantins, UFT, 77020-210 Palmas, TO, Brazil.
Ilsamar Mendes
IM
Soares
Laboratory of Natural Research Products, Faculty of Medicine, Federal University of Tocantins, UFT, 77020-210 Palmas, TO, Brazil.
Sérgio Donizeti
SD
Ascêncio
Physiology Area, Department of Basic Sciences in Health, Faculty of Medicine, Federal University of Mato Grosso, UFMT, 78060-900 Cuiabá, MT, Brazil.
Antonio
A
Macho
Pharmacology Area, Department of Basic Sciences in Health, Faculty of Medicine, Federal University of Mato Grosso, UFMT, 78060-900 Cuiabá, MT, Brazil. Electronic address: taba@terra.com.br.
Domingos Tabajara de Oliveira
DTO
Martins
D034901:Alismataceae / Q000737:chemistry*; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D001249:Asthma / Q000188:drug therapy* / Q000276:immunology; D001938:Brazil; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D002851:Chromatography, High Pressure Liquid; D016207:Cytokines / Q000378:metabolism; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D007249:Inflammation / Q000188:drug therapy / Q000276:immunology; D008297:Male; D051379:Mice; D010047:Ovalbumin / Q000276:immunology; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D018515:Plant Leaves
D000893:Anti-Inflammatory Agents; D016207:Cytokines; D010936:Plant Extracts; D010047:Ovalbumin