Processo de obtenção e avaliação do potencial analgésico, antiinflamatório, toxicidade pré-clínica de zerumbona obtido dos rizomas de Zingiber zerumbet (L.) Smith (Zingiberaceae)

Abstract

Zerumbone is the main sesquiterpene extracyed from the essential oils of the rhizomes of Zingiber zerumbet (L) Smith, which is being studied for decades on account of its antiinflammatory, antisparmodic and cytotoxic analgesic activity against liver, colon and skin cancer tumor cells. The plant is rich in terpenes and glycosylated flavonoides that present pharmacological activities, highlighting its potent activity against cancer neoplastic and Herpes and HIV EBV vírus antiviral cells. The present thesis relates to the improvement of the obtaining process and the preclinical study of the zerumbone compound (ZER). Thin layer chromatography (TLC) on silica gel using iodine, serum sulfate and UV 254nm and 365nm as developers.Essencial oils extracted by hydrodistillation, steam drag, dicloromethane (DCM) and metanol (MeOH) extracts were assessed and the DCM extract showed to bear the highest, but less pure yield. The obtained extracts were characterized with respect to the sesquiterpene compound yield and content by UV-Visible Absorption Spectrophotometry, High Performance Liquid Chromatography (HPLC), gas chromatography and identified by 1 H and 13 C NMR.. The extracts’ phytochemical tests were performed by Mattos (1997) methodology. Mice and rats were used for the preclinical study. For the use of pharmacological animals in vivo and in vitro, the present project was submitted to the Animal Use Ethics Committee- CEUA/INPA. The acute toxicity tests being evaluated during 14 and 30 days and cytotoxicity testing were performed using the Artemia salina test according to Meyer (1982). The acetic acid-induced abdominal contortion test, hot plate and hyperalgesic test were utilized for the study of antinociceptive activity through the chrotonic and capsaicin oil models.The anti-inflammatory and antinociceptive activity were evaluated by the methods of ear and paw edema induced by capsaicin, croton oil, acetic acid, hot plate test.The results obtained with the essential oils extracted by steam distillation provided the lowest, yet very pure, yield percentage (99.95%) purer than that of the previous method (97%), postulated in the patent number PI0505343 -9/28/11/2007.DCM, MEOH and ZER extracts phytochemical screening findings revealed the presence of the following compounds: terpenoids, xanthones, flavonoids, phenols, tannins and alkaloids. EM and DCM TLC indicated a stain revealed in iodine and ceric sulfate with the retention factor of approximately 0.7 cm similar to that of Zerumbona (0.8) and MEOH showing stains in iodine and UV 254 nm. In specific pharmacological and preclinical acute and subchronic toxicity tests in mice and rats, one may state extracts and ZER at doses greater than 5 g / kg did not cause mortality of the animals and did not present toxic effects p.o. Tests of the assessment of the analgesic activity of zerumbone (ZER) in the doses from 250 to 1000mg/kg, showed a potent analgesic effect on pain thermal and chemical models in mice (Mus músculo). ZER administered orally and intraperitoneally produced significant and dose-dependent analgesic activity against the pain, acetic acid, formalin, and capsaicin models. In addition, ZER significantly increased the dormancy of the animals in the hotplate test pain model (49-540C).The results of the effects of the anti-inflammatory activity of zerumbone in a model of the edematogenic inflammatory process (carrageenan, chrotonic oil and arachidonic acid) produced significant dose-dependent antiinflammatory effects in inhibiting the carrageenan inflammatory response in the rat’s paw edema. The effects of the zerumbone substance on barbiturate sleep, using sodium pentobarbital (Nembutal), showed that ZER altered the induction time (I.T) of barbiturate sleep at recovery time (RT) in + 600 minutes. In the in vitro cytotoxicity assays Zerumbone produced the mortality for Artemia saline of - 45 μg / mL, showing a positive correlation between antitumor, anti - inflammatory activities. Findings show ZER to present potent analgesic, antiinflammatory effects, but no toxicit in the laboratory animals orally, to introduce a differentiated biotechnological product into the market and, to make a vakuable contribution to the scientific studies on this rich medicinal plant.