Efeitos estrogênicos da suplementação com extratos de linhaça (Linum usatissimum) e/ou amoreira (Morus nigra) em ratas ovariectomizadas

Abstract

Estrogens are steroid hormones produced mainly by the ovaries and have the action in the growth and development of reproductive organs, among others. From the fifth decade of life of women, there is a decrease in ovarian function and consequently the plasma concentration of estrogen, leading to menopause. Uses of synthetic hormones are the first choice for reducing the signs and symptoms of menopause, however, there are many restrictions. With this, the use of natural substances, such as herbal medicines, has become quite common. Phytotherapy has several types of components, among them so-called phytoestrogens. These constitute a group of non-steroidal compounds found in various plants and are known to mimic or modulate estrogenic action. Among these foods, flaxseed and mulberry tea have been shown to be effective in treating some menopausal disorders. The objective of the present study was to verify the estrogenic effects of supplementation with flaxseed and/or mulberry extracts on the reproductive, metabolic, bone and behavioral systems of ovariectomized animals. Thirty-two adult female Wistar rats, weighing 210g ±10 on average, ovariectomized were divided into five groups: a) treated with saline (saline); b) treated with estrogen (estrogen); c) treated with flaxseed extract (flaxseed); d) treated with mulberry extract (mulberry); e) treated with flaxseed and mulberry extracts (compound). All groups were orally treated for 60 days by gavage with approximately 500 μl/animal, and each week the animals were weighed. After treatment, the rats were submitted to the Elevated Plus Maze (EPM) test, then euthanized in the morning and performed vaginal smear. Blood samples from the animals were collected by cardiac puncture for analysis of plasma concentrations of total cholesterol and fractions, triacylglycerols (TAG), lipase, uric acid, glutamic-oxalacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT). The following were collected: pituitary, liver, uterus, and femur. The pituitary gland was weighed. The liver and uterus were sectioned and fixed in 10% formalin solution. The femur was removed from all soft tissue and decalcified and then sectioned. Histomorphometric analyzes were performed on the uterine wall and femur, and histopathological analysis was performed for the liver samples. The solutions of the flaxseed and mulberry extracts were submitted to the quantification of total phenolic content and antioxidant analysis. The data were submitted to analysis of variance by the F test and the means of the treatments were grouped by the Scott-Knott test at 5% probability. The analyses were generated by the R program and the graphs in the Prisma program. As results, it was verified that the percentage of inhibition of flaxseed extract in sequestering the DPPH radical was 74.55% and the mulberry extract was 73.44%. Only the mulberry extract presented antioxidant activity by the beta-carotene/linoleic acid system in the value of 44.77%, since the flaxseed extract, it was not possible to quantify. The mulberry extract presented total phenolic content (1482.6 ± 37 mg EAG / 100g extract) and flaxseed extract (1395.4 ± 11 mg EAG/100g extract). The groups treated with estrogen and extracts of flaxseed, mulberry, and compound had lower weight gain during treatment and higher pituitary weight compared to saline-treated animals. In the EPM, the animals submitted to the different treatments did not differ among themselves, regarding the length of stay and frequency of entry into the open arms. The animals treated with estrogen and extracts presented vaginal mucosal epithelial cells in the vaginal smear, while the saline-treated animals showed large amounts of leukocytes. Animals receiving estrogen and flaxseed, mulberry and compound extracts exhibited a reduction in plasma concentrations of cholesterol, LDL and lipase, and only the estrogen and compound treated groups showed reduced VLDL and TAG values in relation to saline-treated animals. Plasma concentrations of HDL, uric acid, GOT and GPT did not show differences between treatments. Animals that were treated with estrogen, and extracts of flaxseed, mulberry, and compound showed the greater endometrial thickness and a high percentage of intact trabecular compared to the saline group. Through the histopathological analysis of the liver, it was observed that the animals treated with saline had a greater number of liver changes in relation to the other treatments. Based on these data, it is suggested that supplementation with flaxseed and/or mulberry extracts promoted beneficial effects to the organism without estrogenic action. Thus, an alternative and/or effective complement may be provided to control the effects caused by the decrease in estrogenic action.