Avaliação preliminar in vivo do efeito hipocolesterolêmico do polvilho da fruta-de-lobo (Solanum lycocarpum A. St.-Hil. ) / Preliminary evaluation of in vivo hypocholesterolemic effect of the flour of fruit-of-wolf (Solanum lycocarpum A. St.-Hil. )

O polvilho da fruta-de-lobo é um produto extraído da polpa da fruta-de-lobo verde (Solanum lycocarpum A. St.-Hil.), popularmente utilizado. Pouco se conhece a respeito desse polvilho, mas são atribuídos a ele vários efeitos terapêuticos, dentre eles a redução do colesterol. Este trabalho teve o objetivo de verificar a ação da administração do polvilho da fruta-de-lobo sobre animais hipercolesterolêmico. Utilizou-se 24 ratos Wistar fêmeas distribuídas em delineamento ao acaso, em três grupos contendo 8 animais em cada grupo. Estes grupos foram definidos como: controle normal (CN), controle hipocolesterolêmico (CH) e hipocolesterolêmico tratado (HT). O grupo CN recebeu dieta comercial, os grupo CH e HT receberam a dieta comercial enriquecida de colesterol e ácido cólico e o grupo HT recebeu também, 100 mg de polvilho da fruta-lobo, diariamente, por sonda orogástrica. O experimento teve uma duração de 6 semanas onde se avaliou o colesterol total sérico semanalmente, peso dos animais semanalmente e o consumo diário de ração. Ao término do experimento, foram avaliados os seguintes parâmetros: frações séricas de colesterol HDL, LDL+VLDL, peso do fígado, colesterol total hepático, lipídeos totais hepático e lâminas de microscopia foram feitas para avaliação dos hepatócitos. Não houve diferença significativa em relação ao peso corporal dos animais, ao consumo da dieta e nas análises de colesterol total sérico entre os grupos estudados. Avaliando-se a relação VLDL +LDL/HDL, os níveis encontrados no grupo HT foram significativamente menores que o grupo CH. Já em relação ao colesterol hepático, o grupo HT mostrou níveis menores de colesterol que o CH. Observou-se nos lipídeos hepáticos que não houve diferença significativa entre os grupo CH e HT, e no peso do fígado houve diferença significativa entre os grupos avaliados. Em relação à microscopia, os grupos hipercolesterolêmicos apresentaram discreta vacuolização no citoplasma dos hepatócitos. Concluiu-se, que o polvilho da fruta-de-lobo não influenciou o colesterol sérico dos animais, entretanto, reduziu os níveis de colesterol hepático.

The fruit-of-wolf flour is a product extracted from the pulp of green fruit-of-wolf (Solanum lycocarpum A. St .- Hil.) and is commonly used. Little is known about this flour, but several therapeutic effects, including cholesterol reduction, are attributed to it. This study aimed to verify the action of the administration of fruit-of-wolf flour to hypercholesterolemic animals. We used 24 female Wistar rats allocated in randomized design to three groups containing 8 animals each. These groups were defined as normal control (CN), hypocholesterolemic control (CH) and hypocholesterolemic treated rats (HT). The CN group received a commercial diet, while the CH and the HT group received the commercial diet enriched with cholesterol and cholic acid; the HT group also received 100 mg of fruit-of-wolf flour, daily, by orogastric tube. The experiment lasted for six weeks and the following characteristics were evaluated: weekly total serum cholesterol, weekly weight of animals and daily food intake. At the end of the experiment, we assessed the following parameters: serum cholesterol fractions HDL, LDL + VLDL, liver weight, liver total cholesterol, liver total lipids and microscopic slides were prepared for the evaluation of hepatocytes. There was no significant difference in body weight of animals, diet consumption and analysis of serum total cholesterol among the studied groups. Assessing the relationship VLDL + LDL / HDL, the levels found for the HT group were significantly lower than those for the CH group. As regards liver cholesterol, the HT group showed lower cholesterol levels than the CH group. For liver lipids there was no significant difference between the CH and the HT group, and for liver weight there was no significant difference among the studied groups. As to microscopy, the hypercholesterolemic groups showed slight vacuolization in the cytoplasm of hepatocytes. It was concluded that fruit-of-wolf flour did not influence the serum cholesterol of animals but reduced the levels of liver cholesterol.

Activity of liver microsomal enzymes during the chronic phase of murine schistosomiasis

The effects of schistosomiasis on microsomal enzymes were studied on post-infection day 90 when accumulated damage and fibrosis are most intense but granulomatous reaction around the eggs harbored in the liver is smaller than during the earlier phases. Swiss Webster (SW) and DBA/2 mice of either sex (N = 12 per sex per group) were infected with 100 Schistosoma mansoni cercariae on postnatal day 10 and killed on post-infection day 90. Cytochrome P-450 (CYP) concentration and alkoxyresorufin-O-dealkylases (EROD, MROD, BROD, and PROD), p-nitrophenol-hydroxylase (PNPH), coumarin-7-hydroxylase (COH), and UDP-glucuronosyltransferase (UGT) activities were measured in hepatic microsomes. Age-matched mice of the same sex and strain were used as controls. In S. mansoni-infected mice, CYP1A- and 2B-mediated activities (control = 100 percent) were reduced in SW (EROD: male (M) 36 percent, female (F) 38 percent; MROD: M 38 percent, F 39 percent; BROD: M 46 percent, F 19 percent; PROD: M 50 percent, F 28 percent) and DBA/2 mice (EROD: M 64 percent, F 58 percent; MROD: M 60 percent; BROD: F 49 percent; PROD: M 73 percent) while PNPH (CYP2E1) was decreased in SW (M 31 percent, F 38 percent) but not in DBA/2 mice. COH did not differ between infected and control DBA/2 and UGT, a phase-2 enzyme, was not altered by infection. In conclusion, chronic S. mansoni infection reduced total CYP content and all CYP-mediated activities evaluated in SW mice, including those catalyzed by CYP2E1 (PNPH), CYP1A (EROD, MROD) and 2B (BROD, PROD). In DBA/2 mice, however, CYP2A5- and 2E1-mediated activities remained unchanged while total CYP content and activities mediated by other CYP isoforms were depressed during chronic schistosomiasis.

Induction of liver monooxygenases by annatto and bixin in female rats

Annatto or urucum is an orange-yellow dye obtained from Bixa orellana seeds. It has been used as a natural dye in a variety of food products, drugs and cosmetics, and also in Brazilian cuisine as a condiment ('colorau'). Bixin, a carotenoid devoid of provitamin A activity, is the main pigment found in annatto. Some carotenoids (canthaxanthin, astaxanthin and á-Apo-8'-carotenal) are known to be potent inducers of CYP1A1, a property not shared by others (á-carotene, lycopene and lutein). Little is known, however, about the CYP1A1-inducing properties of bixin and annatto. The present study was performed to determine the effects of an annatto extract (28 percent bixin) and bixin (95 percent pure) on rat liver monooxygenases. Adult female Wistar rats were treated by gavage with daily doses of annatto (250 mg/kg body weight, which contains approximately 70 mg bixin/kg body weight), bixin (250 mg/kg body weight) or the vehicle only (corn oil, 3.75 g/kg body weight) for 5 consecutive days, or were not treated (untreated control). The activities of aniline-4-hydroxylase (A4H), ethoxycoumarin-O-deethylase (ECOD), ethoxy- (EROD), methoxy- (MROD), pentoxy- (PROD) and benzyloxy- (BROD) resorufin-O-dealkylases were measured in liver microsomes. Annatto (250 mg/kg containing 70 mg bixin/kg) induced EROD (3.8x), MROD (4.2x), BROD (3.3x) and PROD (2.4x). Bixin (250 mg/kg) was a weaker inducer of EROD (2.7x), MROD (2.3x) and BROD (1.9x) and did not alter PROD, A4H or ECOD activities. These results suggest that constituents of the extract other than bixin play an important role in the induction of CYP1A and CYP2B observed with annatto food colorings