Medicarpin

Medicarpin inhibits osteoclastogenesis and has nonestrogenic bone conserving effect in ovariectomized mice.[Pubmed:20570709]

Mol Cell Endocrinol. 2010 Aug 30;325(1-2):101-9.

Medicarpin, a pterocarpan class of naturally occurring benzopyran furanobenzene compound was synthesized in gram scale to investigate its effects on murine bone cells and in ovariectomized (OVx) mice. Medicarpin, at as low as 10(-10)M suppressed osteoclastogenesis in bone marrow cells (BMCs). Medicarpin-induced apoptosis of mature osteoclasts isolated from long bones. Effects of Medicarpin in osteoclasts appear to be independent of estrogen receptor (ER) activation as ICI 180,782 failed to abrogate its effects on osteoclasts. In calvarial osteoblasts, Medicarpin (10(-10)M) blocked nuclear factor kappaB (NF-kappaB) signaling assessed by tumor necrosis factor alpha (TNFalpha)-stimulated nuclear translocation of p65 subunit of NF-kappaB. Medicarpin also inhibited the expression of TNFalpha in mouse calvarial osteoblasts. This effect was ER dependent as ICI 180,782 reversed the suppressive effect of Medicarpin on TNFalpha mRNA levels in osteoblasts. In addition, like 17beta-estradiol, presence of Medicarpin inhibited TNFalpha-induced upregulation of interleukin-1, and -6 mRNA levels in osteoblasts. In co-cultures consisting of calvarial osteoblasts and BMCs, presence of Medicarpin increased osteoprotegerin (OPG)/receptor activator of NF-kappaB ligand (RANKL) ratio and reduced mRNA levels of osteoclast markers including tartrate-resistant acid phosphatase and RANK. OVx mice administered Medicarpin (10.0mgkg(-1)day(-1)) orally for 30days had reduced formation of osteoclasts but increased formation of osteoprogenitor cells in BMCs compared with OVx+vehicle group. Medicarpin treatment to OVx mice maintained parameters of trabecular microarchitecure. Medicarpin exhibited no uterine estrogenicity. Our findings point towards direct and indirect inhibitory effects of Medicarpin on osteoclastogenesis in vitro that contribute to its bone sparing effect in OVx mice.

Specificity of medicarpin and related isoflavonoids in inhibition of rat hepatic mixed function oxidase activity.[Pubmed:3877941]

Pharmacology. 1985;31(5):289-93.

The cytochromes P-450 of the mixed function oxidase system metabolize a wide variety of endogenous compounds to either nontoxic products or toxic metabolites. A number of natural products, such as flavonoids, influence this metabolism. Exposure to these compounds may therefore be a factor in animal and human responsiveness to cytochrome P-450 substrates. We have examined the effect of the pterocarpan Medicarpin on the cytochrome P-450-dependent aryl hydrocarbon hydroxylase (AHH) and ethoxycoumarin deethylase (ECD) activities of rat liver microsomes. Medicarpin and maackiain and two of their biosynthetic precursors inhibit the constitutive and phenobarbital (PB)-induced types of AHH, but have little effect on the 3-methylcholanthrene (MC)-induced type of AHH. This is in contrast to the effect of the commonly used cytochrome P-450 inhibitor 7,8-benzoflavone, which inhibits the hepatic AHH of MC-treated rats and has no effects on the AHH of control or PB-treated rats. However, Medicarpin inhibited the constitutive as well as the PB- and MC-induced ECD. The specific modulatory effect as well as its relative availability suggests the utility of Medicarpin as a probe for different forms of cytochrome P-450 in animal tissues.

Medicarpin, a legume phytoalexin, stimulates osteoblast differentiation and promotes peak bone mass achievement in rats: evidence for estrogen receptor beta-mediated osteogenic action of medicarpin.[Pubmed:21333515]

J Nutr Biochem. 2012 Jan;23(1):27-38.

Dietary isoflavones including genistein and daidzein have been shown to have favorable bone conserving effects during estrogen deficiency in experimental animals and humans. We have evaluated osteogenic effect of Medicarpin (Med); a phytoalexin that is structurally related to isoflavones and is found in dietary legumes. Med stimulated osteoblast differentiation and mineralization at as low as 10(-)(1)(0) M. Studies with signal transduction inhibitors demonstrated involvement of a p38 mitogen activated protein kinase-ER-bone morphogenic protein-2 pathway in mediating Med action in osteoblasts. Co-activator interaction studies demonstrated that Med acted as an estrogen receptor (ER) agonist; however, in contrast to 17beta-estradiol, Med had no uterine estrogenicity and blocked proliferation of MCF-7 cells. Med increased protein levels of ERbeta in osteoblasts. Selective knockdown of ERalpha and ERbeta in osteoblasts established that osteogenic action of Med is ERbeta-dependent. Female Sprague-Dawley (weaning) rats were administered Med at 1.0- and 10.0 mg.kg(-)(1) doses by gavage for 30 days along with vehicle control. Med treatment resulted in increased formation of osteoporgenitor cells in the bone marrow and osteoid formation (mineralization surface, mineral apposition/bone formation rates) compared with vehicle group. In addition, Med increased cortical thickness and bone biomechanical strength. In pharmacokinetic studies, Med exhibited oral bioavailability of 22.34% and did not produce equol. Together, our results demonstrate Med stimulates osteoblast differentiation likely via ERbeta, promotes achievement of peak bone mass, and is devoid of uterine estrogenicity. In addition, given its excellent oral bioavailability, Med can be potential osteogenic agent.

Medicarpin, a legume phytoalexin sensitizes myeloid leukemia cells to TRAIL-induced apoptosis through the induction of DR5 and activation of the ROS-JNK-CHOP pathway.[Pubmed:25321472]

Cell Death Dis. 2014 Oct 16;5:e1465.

Tumor necrosis factor alpha-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent with cancer cell-selective cell death inducing effect. However, the major limitation in the usage of TRAIL as a chemotherapeutic agent is the development of TRAIL resistance in many cancer types including myeloid leukemia. In this study, we report for the first time that Medicarpin (Med), a naturally occurring phytoalexin sensitizes myeloid leukemia cells to TRAIL-induced apoptosis. Combination of Med and TRAIL induced significantly higher apoptosis compared with that of the individual treatments of either agent alone through activation of both the extrinsic and the intrinsic cell death pathways characterized by the activation of caspases 8, 9, 3, and 7. Med treatment downregulated antiapoptotic proteins (Survivin, Bcl2, Bcl-xL, XIAP, and c-FLIP), upregulated pro-apoptotic proteins (Bax, Cytochrome C, Smac/Diablo, Bid, truncated Bid (tBid), p-eIF2alpha, Bip, and CHOP (CCAAT-enhancer binding protein homologous protein)), induced G2/M cell-cycle arrest, and increased the expression of the functional TRAIL receptor DR5 through activation of the ROS-JNK-CHOP pathway. Gain and loss of function studies clearly indicated that DR5 expression was critical for Med-induced TRAIL sensitization. The Med-induced TRAIL sensitization did not involve the NFkB signaling pathway or redistribution of DR5 in lipid rafts. The concomitant treatment with Med and TRAIL showed robust apoptotic effects in primary myeloid leukemia cells but had no toxic effects in primary human peripheral blood mononuclear cells (PBMCs). In conclusion, our results suggest that Med sensitizes myeloid leukemia cells to TRAIL-induced apoptosis through the upregulation of DR5 through activation of the ROS-JNK-CHOP pathway.

Effect of lead treatment on medicarpin accumulation and on the gene expression of key enzymes involved in medicarpin biosynthesis in Medicago sativa L.[Pubmed:25053287]

Environ Sci Pollut Res Int. 2014 Dec;21(24):14091-8.

Lead (Pb) is the most common heavy metal contaminant in the environment. The present study was undertaken to determine the effect of Pb treatment on Medicarpin production and accumulation in Medicago sativa L. To this aim, 7- and 30-day-old plants were treated with 0, 120, 240, 500, and 1,000 muM Pb during 10 days. The content of Medicarpin was determined by HPLC, and the extent of Medicarpin production was deduced from the result of semiquantitative RT-PCR performed on PAL, CHS, and VR genes. HPLC results indicated that Medicarpin concentration has been reduced in the roots, while its exudation to the culture medium has been increased. RT-PCR results indicated that the transcript levels of PAL, CHS, and VR genes have not been affected following Pb stress in seedlings. At the vegetative stage, transcript levels of PAL and CHS genes have been reduced in the roots. However, the transcript level of VR gene increased at 120 and 240 muM Pb, while it decreased at higher concentrations. In the shoot, the transcript levels of PAL, CHS, and VR genes were increased following increased concentration of lead in the medium. Overall, q-PCR results suggest that Medicarpin biosynthesis has been induced in the shoots and reduced in the roots of the plants treated with a toxic concentration of Pb.