Impact of Pueraria candollei var. mirifica and its potent phytoestrogen miroestrol on expression of bone-specific genes in ovariectomized mice Latiporn Udomsuk a, b , Waranya Chatuphonprasert a, c , Orawan Monthakantirat d , Yaowared Churikhit d , Kanokwan Jarukamjorn a, d, ⁎ a Research Group for Pharmaceutical Activities of Natural Products using Pharmaceutical Biotechnology (PANPB), National Research University-Khon Kaen University, Khon Kaen 40002, Thailand b College of Medicine and Public Health, Ubon Ratchatani Universty, Ubon Ratchatani 34190, Thailand c Faculty of Medicines, Mahasarakham University, Mahasarakham 44000, Thailand d Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand article info abstract Article history: Received 22 July 2012 Accepted in revised form 21 September 2012 Available online 4 October 2012 Miroestrol (MR) is a highly active phytoestrogen isolated from tuberous root of Pueraria candollei var. mirifica (PM). Modulatory effects of PM and MR on osteoprotegerin (OPG) and receptor activator of nuclear factor kappa B ligand (RANKL) mRNAs which are bone-specific genes were investigated in ovariectomized female ICR mice. After ovariectomy, expression of OPG mRNA was suppressed but that of RANKL was induced. Estradiol benzoate (E2) recovered OPG expression to the level comparable to the sham while that of RANKL was suppressed in ovariectomized mice. PM crude extract (PME) significantly down-regulated the expression of RANKL mRNA with no change in the OPG level whereas MR elevated the expression of OPG mRNA with lowering level of RANKL mRNA, resulting in the increased OPG/RANKL ratio, and consequently lead to lowering progression of osteoporosis at molecular level. These findings revealed potential of PME and MR on bone loss prevention via increasing the ratio of OPG to RANKL (osteoformation/osteoresorption) in liver of ovariectomized mice. Therefore, using PME and MR as alternative hormone replacement therapy of E2 might be beneficial recommended due to advantageous on regulation of osteoporosis related genes. © 2012 Elsevier B.V. All rights reserved. Keywords: Estradiol Miroestrol OPG Osteoporosis Pueraria candollei var. mirifica RANKL 1. Introduction Osteoporosis is a worldwide public health problem and most prevalent in women over the age of 50 as the hormonal influence of estrogen on bone health dissipates with the onset of menopause [1]. The progressive changes in bone structure, quality, and density lead to pathological fractures and increase in morbidity and mortality among menopausal women [2]. Asian population showed the lower incidence of osteoporosis-related fractures than European [3]. Recently, due to the report about risk of some cancers such as breast, endometrial, and ovarian associated with the use of synthetic estrogen replacement therapy, phytoestrogens become popular [4]. Many women have turned to interest phytotherapy and considered it as an alternative to estrogen replacement therapy for prevention and treatment of osteoporosis [5]. Phytoestrogen is a popular natural compound used in many countries [6]. Pueraria candollei var. mirifica (PM) or Kwao Kruea Khao is well known in Thai traditional medicine due to its rejuvenation properties [7]. There are several reports noted on the potential of PM on bone loss. For example, PM has been shown to prevent osteoporosis dose- dependently in ovariectomized rats by increasing bone mineral density and bone mineral content [8,9]. In addition, a very recent study demonstrated that PME and its isoflavone, puerarin, possibly enhanced bone formation by promoting osteoblast differentiation via up-regulation of ALP mRNA expression and Fitoterapia 83 (2012) 1687–1692 ⁎ Corresponding author at: Research Group for Pharmaceutical Activities of Natural Products using Pharmaceutical Biotechnology (PANPB), Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand. Tel.: +66 43 202378x1510, 3622; fax: +66 43 202305. E-mail address: kanok_ja@kku.ac.th (K. Jarukamjorn). 0367-326X/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.fitote.2012.09.024 Contents lists available at SciVerse ScienceDirect Fitoterapia journal homepage: www.elsevier.com/locate/fitote