Composição química, atividade anti-inflamatória e toxicidade aguda e subaguda de Verbena litoralis kunth

Abstract

Verbena litoralis Kunth belongs to the Verbenaceae family, which is native to South America and can be found in tropical and subtropical regions, especially in the temperate regions of the Southern Hemisphere. It is popularly known as gervãozinho-do-campo or erva-de-pai-caetano and used in traditional medicine as antidiarrheal, febrifuge, gastrointestinal disorders, inflammation of the uterus and ovary. Although widely used for therapeutic purposes, the anti-inflammatory properties, toxic characteristics as well as the phytochemical composition of the crude extract of the plant are not yet fully understood. Thus, the objective of this work was to identify the phytochemical constituents in the crude extract of the aerial parts of Verbena litoralis, to evaluate the anti-inflammatory activity and to determine the toxicity. Chlorogenic acid, vanillic acid, caffeic acid, p-coumaric acid, ferulic acid, luteolin, apigenin, trans-cinnamic acid, quercetin, griselinoside, hispidulin 7-O-glucuronide, acetylacteoside and nodifloretin were identified by CLUE/EM. The crude extract and the ethyl acetate fraction showed significant inhibitory activity in the formation of the granulomatous tissue, indicating a potential anti-inflammatory action of Verbena litoralis. In the acute toxicity analysis a single dose of 2000 mg/kg of V. litoralis was administered orally to rats of both sexes. After administration the plant can be considered safe (category 5) according to the OECD guide. In the subacute toxicity study the plant extract was administered orally to male and female rats at doses of 100, 200 and 400 mg/kg for 28 days. Hematological, biochemical and histological parameters were analyzed. Male rats treated with 400 mg/kg extract showed a significant increase in erythrocyte count and in the enzyme aspartate amino transferase. Histological examination of the male and female liver showed some alterations such as sinusoidal dilatation and vascular dilation, respectively, but the hepatocytes remained intact. When analyzing the renal histology, some modifications were observed in the groups treated with 400 mg/kg of plant extract in both sexes, such as dilatation and congestion of the vessels and increase of the tubular lumen, but it was believed that they were not enough to alter the function of this tissue, since creatinine levels remained unchanged and the proximal and distal convoluted tubules remained intact. Therefore, this result brings some caution when making use of the plant for successive days.