Researches of Pueraria Mirifica

Estradiol Replacement in Ovariectomized Rats Is Antihyperalgesic in the Formalin Test

Abstract: A subcutaneous implant of 17β-estradiol or progesterone provides steady-state serum hormone levels from 7 to 24 days after implantation and allows the evaluation of the effects of the replacement with these hormones on phase 1 and phase 2 formalin-induced behaviors in ovariectomized (OVX) rats. Graded doses of 17β-estradiol (5% to 40%) reduce formalin-induced behavior by 35% to 49% during phase 2 but not during phase 1, as measured with an automated formalin apparatus. The maximal response is seen with 20% 17β-estradiol. The antihyperalgesic effect of 20% 17β-estradiol is significant at 8 days after implantation and persists at 21 days. In contrast, graded doses of progesterone have no effect on either phase of formalin. The estrogen receptor antagonist tamoxifen completely prevents the antihyperalgesic effect of the 20% 17β-estradiol implant. Formalin- induced behaviors during phase 2 are significantly less in proestrus females and OVX rats given 20% 17β-estradiol compared with OVX control rats. Also, the formalin-induced increase in serum corticosterone is attenuated in OVX control rats compared with proestrus females and OVX rats given 20% 17β-estradiol. These results indicate that estrogen replacement in OVX rats restores the maximal corticosterone response to tonic pain and, by an estrogen receptor–mediated process, inhibits tonic pain. Perspective: Hormone replacement (HR) therapy remains a widely used modality. We used a pharmacokinetically based rat HR model that results in continuous physiological levels of 17β-estradiol to demonstrate the analgesic (antihyperalgesic) effects of estrogen replacement in an inflammatory pain model (formalin). These results suggest a potentially important consequence of HR therapy.

Pretreatment with phytoestrogen-rich plant decreases breast tumor incidence and exhibits lower profile of mammary ERα and ERβ

Objective: Phytoestrogens have been reported to exhibit antiproliferation to human breast cancer cells in vitro. We tested the phytoestrogen-rich, Pueraria mirifica against rat breast cancer induction in vivo.

Methods: The weanling female Spargue-Dawley rats were pretreated with P. mirifica tuberous powder at a dosage of 0, 10, 100 and 1000 mg/kg BW/day for four consecutive weeks. Mammary tumor development was then induced with a single dose of 7,12-DMBA, 80 mg/kg BW, followed by a weekly examination for size and multiplicity of mammary tumors for 20 weeks and finally a necropsy. Mammary tissues were investigated for the virulence of tumor and also monoclonal antibody stained against ERa and ERß.

Results: Pretreatment of 1000 mg/(kgBWday) of P. mirifica tuberous powder resulted in decreasing of the virulence of rat tumor development. The mammary tumor tissues exhibited lower profile of ERa and ERß as well a sERa and ERß

Conclusion: P. mirifica exhibited prevention of 7,12-DMBA-induced rat mammary tumors, with a proposed mechanism of strong competitive binding of its phytoestrogens to ERa and/or synthesis suppressor of ERa.

Pueraria Mirifica initiative promotes the cellular mechanism of neuronal survival in neuron human neuroblastoma cells.

Pueraria Mirifica (PM) or White Kwao Krue (Thai Herb) has been used as a rejuvenator for long time in aging. It contains a variety of phytoestrogens that possess the highest estrogenic activity. In molecular research and epidemiological data show that estrogen replacement therapy (ERT) can decrease the risk of developing Alzheimer's disease. Interestingly, whether the estrogenic effect of PM can prevent neurotrophic from neurotoxic agents e.g. glutamate, H2O2, and beta-amyloid 25-35 in AD model. What a mechanism of PM that prevents neuronal cell death is.

Objectives: The current study investigated the neurotrophic and neuroprotective action of the complex formulation of phytoestrogen from a standardized PM extract compare with 17b-estradiol in AD model in vitro.

Methods: Crude PM was extracted by ethanol and standardized by HPLC. Action of standarize PM was pretreated in human neuroblastoma cell line (LA-N5) in complete media of estrogen deprivation condition with neurotoxic agents; 0.2mM glutamate, 20µM H2O2, and 8 µg/ml beta-amyloid 25-35 by inhibit cell death. By using inverted microscope, morphologic and biochemical analysis were conducted in neuroblastoma cultures to determine the neurotrophic and neuroprotective properties of standardize PM and 17b-estradiol. Using ICI anti-estrogenic activity and estrogen dependent breast cancer cell for demonstrate the inhibition of PM in estrogen receptor pathway in AD model.

Results: the results demonstrated that PM significantly decreased neuronal cell death in a time and dose dependent fashion. Results of neuroprotection studies demonstrated that PM and 10-8 M 17b-estradiol induced highly significant neuroprotection against beta-amyloid, hydrogen peroxide, glutamate-induced toxicity. Inhibi action of PM and 17b-estradiol by estrogen antagonist (ICI164,384) after induce with neurotoxic agents that show significantly increase cell death.

Conclusions: PM shows estrogenic activity similar 17b-estradiol and prevents neurotoxic agents for neuronal dead significantly by may pass estrogen pathway. For clinical application of PM possible to use for intervention in Alzheimer's disease and other neurodegenerative disease in aging in the near future.

The Estrogenic Effect of Pueraria mirifica on Gonadotrophin Levels in Aged Monkeys

We investigated the effect of Pueraria mirifica (PM) on gonadotrophin and estradiol levels in aged animals; nine menopausal cynomolgus monkeys were divided into three groups. Each group (n = 3) was fed with 10, 100, and 1000 mg/d of PM for 90 d. PM-10 induced the decrease of follicle stimulating hormone (FSH) levels on d 15–90 in one out of three monkeys. PM-100 and PM-1000 decreased FSH levels of all monkeys throughout the treatment period. After the treatment period, FSH levels continued to decrease for 5 and 10– 20 d in PM-100 and PM-1000, respectively, and the levels rebounded in all groups thereafter. PM-10 decreased luteinizing hormone (LH) levels throughout the treatment period in one out of three monkeys and returned to the pretreatment levels immediately after stopping treatment. PM-100 and PM-1000 prominently decreased LH levels between d 10 and 90 during treatment and persisted until d 15–25 and d 20–30 for PM- 100 and PM-1000, respectively, during the post-treatment period. Serum LH levels rebounded after returning to pre-treatment levels in a dose-dependent manner. Estradiol levels tended to decrease during the treatment period in all groups. The daily feeding of PM suppressed gonadotrophin levels in aged menopausal monkeys based on dose. Moreover, they can be recovered, and there is a direct correlation between dosage and recovery time. PM may be effective as an alternative medicine in menopausal women because the effects are not permanent.