Detection of Isoflavones in Mouse Tibia After Feeding Daidzein

Wendy E. Ward, M.Sc,Debbie Fonseca 한국식품영양과학회 2006 Journal of medicinal food Vol.9 No.3

Many studies suggest that diets rich in isoflavones protect against bone loss or slow the loss of bone mass thatoccurs because of estrogen withdrawal. Although in vitrostudies have reported effects of isoflavones on bone cells, the pres-ence of daidzein and/or equol in bone tissue in vivo has not been reported. The objective of this study was to determine ifdaidzein and equol were present in bone tissue (tibias) after feeding mice a diet containing purified daidzein. Sham mice (n .9) received control diet, and ovariectomized mice were randomized to control diet (Ovx) (n . 9) or control diet containing200 mg of daidzein/kg of diet (n . 8) for 12 weeks. At necropsy, tibias and serum were collected. Mice in the Daidzein grouphad significantly higher (P. .05) levels of both daidzein and equol in tibias than Sham and Ovx mice. Tibia levels of daidzeinand equol were approximately five and four times higher, respectively, than the Sham and Ovx groups. Similarly, mice feddaidzein also had significantly higher (P. .05) serum daidzein and equol than the Sham and Ovx mice. In conclusion, feed-ing a level of daidzein that is attainable by dietary intervention alone results in a high level of both daidzein and equol in tib-ias. These findings suggest that daidzein and its metabolite, equol, have the potential to act directly on bone cells in vivo.

Black Tea Exhibits a Dose-Dependent Response in Saos-2 Cell Mineralization

Riley E. Cleverdon,Michael D. McAlpine,Wendy E. Ward 한국식품영양과학회 2020 Journal of medicinal food Vol.23 No.9

Higher bone mineral density (BMD) is often associated with greater consumption of black tea (BT). However, the dose–response of BT on mineralization in an osteoblast cell model has not yet been studied. The study objective was to determine the dose-dependent response of BT in Saos-2 cells and investigate changes to several proteins involved in the mineralization process. Mineralization was induced in the presence of BT at concentrations that represent levels likely achieved through daily consumption (0.1, 0.5, 0.75, 1 μg gallic acid equivalents [GAE]/mL) or through supplementation (2, 5, or 10 μg GAE/mL). BT exerted a positive dose–response on bone mineralization, peaking at 1 μg GAE/mL of BT (P < .05). Cellular activity was significantly greater than control with exposure to 2–10 μg GAE/mL of BT (at 24 h) (P < .05) and 1–10 μg GAE/mL (at 48 h) (P < .05), with a peak at 5 μg GAE/mL at 24 and 48 h (P < .05). Protein expression of alkaline phosphatase and ectonucleotide pyrophosphatase/phosphodiesterase-1 were unchanged, whereas a moderate dose of BT (0.75 μg GAE/mL) resulted in greater expression of osteopontin compared with the highest dose (10 μg GAE/mL) (P < .05). Doses of BT from 0.5 to 10 μg GAE/mL resulted in higher antioxidant capacity compared with control (P < .05). In summary, the higher antioxidant capacity, enhanced cell viability, and upregulated mineralization suggest that consumption of BT may have a positive effect on BMD at levels obtained through consumption of tea.

Black and Green Tea as Well as Specialty Teas Increase Osteoblast Mineralization with Varying Effectiveness

Michael D. McAlpine,William Gittings,Adam J. MacNeil,Wendy E. Ward 한국식품영양과학회 2021 Journal of medicinal food Vol.24 No.8

Many human studies suggest a benefit of tea consumption on bone health. The study objective was to compare the ability of different tea types to promote mineralization. Saos-2 cells underwent mineralization (5 days) in the presence of tea (white: WT, green: GT, black: BT, green rooibos: GR, or red rooibos: RR; 1 μg/mL of polyphenols) or control. Total polyphenol content (TPC, Folin-Ciocalteu's reagent), antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl [DPPH] scavenging), mineralization (Alizarin Red staining), gene expression quantitative reverse transcription PCR (RT-qPCR), and cell activity (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay) were determined. TPC was highest in GT and BT. The ability of each tea to inhibit DPPH also differed (WT, GT > RR) after normalizing for polyphenol quantity. Each tea increased mineralization and differences were observed among types (GT/BT/GR/RR > WT, GT = BT = GR, RR > BT/GT). mRNA expression of alkaline phosphatase (ALP) and ectonucleotide pyrophosphatase/phosphodiesterase (NPP1) remained unchanged, whereas osteopontin (OPN) and sclerostin (SOST) were reduced in cells treated with tea, regardless of type. At 24- and 48-h postexposure to tea, cell activity was greater in cells receiving any of the teas compared with vehicle control. Supplementation increased mineralization regardless of tea type with both rooibos teas and black tea stimulating greater mineralization than WT, whereas green tea is similar to the others. While future study is needed to confirm in vivo effects, the results suggest that consuming any of the teas studied may benefit bone health.

Accessibility of ³H-Secoisolariciresinol Diglycoside Lignan Metabolites in Skeletal Tissue of Ovariectomized Rats

Sandra M. Sacco,Lilian U. Thompson,Bernhard Ganss,Wendy E. Ward, M. 한국식품영양과학회 2011 Journal of medicinal food Vol.14 No.10

Flaxseed, rich in the phytoestrogen lignan secoisolariciresinol diglycoside (SDG), provides protection against bone loss at the lumbar vertebrae primarily when combined with low-dose estrogen therapy in the ovariectomized rat model of postmenopausal osteoporosis. Whether SDG metabolites are accessible to skeletal tissue, and thus have the potential to interact with low-dose estrogen therapy to exert direct local action on bone metabolism, is unknown. The objective of this study was to determine whether metabolites of SDG are accessible to the skeleton of ovariectomized rats and to compare the distribution of SDG metabolites in skeletal tissue with that in other tissues. Rats were fed a 10% flaxseed diet and gavaged daily with tritium-labeled SDG (7.4 kBq/g of body weight) in deionized water (500 μL) (n=3) or deionized water alone (n=3) for 7 days, after which tissues were collected for liquid scintillation counting. Radioactivity was detected in similar concentrations in the lumbar vertebrae, femurs, and tibias. Compared with non-skeletal tissues, total radioactivity in the skeleton was significantly lower than in the liver, heart, kidney, thymus, and brain (P<.001). There were no significant differences in levels of radioactivity between skeletal tissue versus the spleen, lung, bladder, uterus, vagina, and mammary gland. In conclusion, SDG metabolites are accessible to skeletal tissue of ovariectomized rats. Thus, it is biologically plausible that SDG metabolites may play a direct role in the protective effects of flaxseed combined with low-dose estrogen therapy against the loss of bone mass and bone strength in the ovariectomized rat model of postmenopausal osteoporosis.

Flaxseed Does Not Enhance the Estrogenic Effect of Low-Dose Estrogen Therapy on Markers of Uterine Health in Ovariectomized Rats

Sandra M. Sacco,Jessica M.Y. Jiang,Lilian U. Thompson,Wendy E. Ward, M.Sc 한국식품영양과학회 2012 Journal of medicinal food Vol.15 No.9

Flaxseed (FS) is an oilseed rich in phytoestrogens and n-3 polyunsaturated fatty acids, compounds that may attenuate bone loss during aging. We previously demonstrated using the ovariectomized (OVX) rat model of postmenopausal osteoporosis that 10% dietary FS combined with low-dose estrogen therapy (LD) preserves vertebral bone mass and strength more so than either treatment alone. However, it was prudent to also consider the effect of this intervention on uterine tissue as LD, and possibly FS, may have estrogenic, and thus negative, effects on uterine tissue. The present study investigated if FS enhances the estrogenic effect of LD on markers of uterine health in OVX rats. Three-month-old rats were randomized to groups: (1) SHAM, (2) OVX, (3) OVX+FS, (4) OVX+LD, or (5) OVX+FS+LD. Ground FS was added to the AIN-93M diet (100 g/kg of diet), and LD was delivered by subcutaneous implant (0.42 μg of 17β-estradiol/kg of body weight/day) to mimic LD in postmenopausal women. After 12 weeks, histological analyses of uterine tissue demonstrated flattened or cuboidal luminal epithelia organized in a single layer in the OVX group, while FS, LD, and FS+LD induced a single layer of elongated luminal epithelia, columnar in shape. The SHAM group had the greatest epithelial mass. Cell proliferation was similar among all OVX groups. Therefore FS and FS+LD similarly induce estrogen-like effects on the morphology of luminal epithelia that are weaker than in the SHAM group without inducing cell proliferation in OVX rats. Thus, FS does not enhance the estrogenic effect of LD on markers of uterine health in OVX rats.