Tissue Distribution of Orally Administered Prenylated Isoflavones, Glyceollins, in Sprague-Dawley Rats

Natural glyceollin soybean extracts elicited with Aspergillus sojae reduce estrogen-dependent breast cancer growth in orally fed mice

Previous studies have demonstrated antiestrogenic and antiproliferative effects of these molecules in breast cancer cells. Notably, we have reported that pure synthetic glyceollins I and II act through various pathways, including ERα, FOXM1, AhR, and HIF pathways to inhibit cell proliferation and migration. In this study, the potential antitumor activity of glyceollins enriched in crude soybean extracts, obtained by solid fermentation with Aspergillus sojae, was investigated in vivo on MCF-7 breast cancer cells implanted in the chorioallantoic membrane of the chick egg and on ovariectomized nude mice. The first trial showed a substantial reduction in the migration of MCF-7 cells treated with the natural extracts. However, the natural extracts significantly reduced the estrogen-dependent growth of transplanted tumors in orally fed nude mice. Our results showed that natural soybean extracts slightly but significantly reduced estrogen-dependent growth of the transplanted tumors in orally fed nude mice. These results were confirmed by immunohistochemistry of Ki-67 and histone H3S10 phosphorylation (H3S10P), revealing lower expression of these proliferation markers in the transplanted tumors from mice fed with the fermented extracts. Additionally, compared to the control animals, we observed a lower expression of angiogenesis markers such as CD31 and CD34. Surprisingly, transcriptomic analysis of RNA from transplanted MCF-7 cells revealed no differential gene expression. These results may suggest that orally consumed natural glyceollins exert biological effects throughout the body, acting indirectly to reduce tumor angiogenesis and consequently tumor volume. Overall, our results indicate that glyceollins, elicited components of the soy origin, hold potential therapeutic applications for the prevention and treatment of breast cancer.

Tissue distribution and pharmacokinetics of isoxanthohumol from hops in rodents

Vegetables and fruits contain prenylflavonoids with biological functions that might improve human health. The prenylflavonoid isoxanthohumol (IXA) and its derivative, 8-prenylnaringenin (8-PN), have beneficial activities, including anti-cancer effects and suppression of insulin resistance. However, their pharmacokinetic profile is unclear. Previous studies suggested flavonoids have low systemic availability and are excreted via the feces. Therefore, this study investigated the tissue distribution dynamics of high-purity IXA (>90%) from hops administered orally, either singly (50 mg/kg body weight [BW]) or daily for 14 days (30 mg/kg BW), to mice. High-pressure liquid chromatography demonstrated that IXA was absorbed rapidly after a single administration and reached plasma maximum concentration (C max) (3.95 ± 0.81 μmol/L) by 0.5 h. IXA was present at high levels in the liver compared with the kidney, pancreas, lung, skeletal muscle, spleen, thymus, and heart. The highest IXA level after 14 days of IXA ingestion was observed in the liver, followed by the kidney, thymus, spleen, lung, and brain. There was no significant difference in IXA accumulation in tissues between the single and multiple dose groups. Analyses of the livers of rats treated with different concentrations of IXA (112.5-1500 mg/kg BW) once a day for 28 days demonstrated that IXA accumulated dose-dependently with a correlation coefficient of .813. The accumulation of 8-PN was dependent on the intake period but not the intake amount of IXA (correlation coefficient -.255). In summary, IXA and 8-PN were detected in tissues and organs up to 24 h after ingestion, suggesting that orally ingested IXA might have health benefits as a nutraceutical.

In Vitro and in Silico Analyses of the Adiponectin Receptor Agonistic Action of Soybean Tripeptides

The Tyr-Pro (YP) dipeptide can serve as an adiponectin receptor 1 (AdipoR1) agonist. We thus investigated the AdipoR1-agonistic potential of YP-related tripeptides in the soybean protein sequence. Among the 17 soybean candidate tripeptides, those elongated at the C-terminus of YP (0.1 μM YPG, 140 ± 16%; 0.1 μM YPE, 141 ± 22%; 0.1 μM YPP, 145 ± 19%; 0.1 μM YPQ, 143 ± 20%; p < 0.05) significantly promoted glucose uptake by L6 muscle myotubes, comparable to the effect of 0.1 μM AdipoRon (163 ± 52%, p < 0.05). The knockdown of AdipoR1 expression in L6 cells abrogated this effect of YPG and YPP, indicating that the two tripeptides had an AdipoR1 agonistic effect. CHARMM-GUI-aided molecular dynamics simulation in a virtual phospholipid membrane revealed that YPG and YPP were stably positioned at the binding pockets of AdipoR1 (binding free energy < -10 kcal/mol). These findings demonstrate that the tripeptides YPG and YPP, with AdipoR1 agonistic YP sequences, have alternative adiponectin-like potential via their preferential binding to AdipoR1.