Tracking deposition of a ¹⁴C-radiolabeled kudzu hairy root-derived isoflavone-rich fraction into bone

Abstract

Hairy roots were induced in four genotypes from three kudzu species (Pueraria montana var. lobata, P. lobata and P. phaseoloides) in vitro using Agrobacterium rhizogenes to stimulate rapid secondary metabolite synthesis. Hairy roots from P. montana var. lobata (United States Department of Agriculture no. PI 434246) yielded the highest puerarin and total isoflavone content and the greatest new biomass per growth cycle among the genotypes evaluated. Hairy roots from this genotype were selected for radiolabeling using (14)C-sucrose as a carbon source. Isoflavones from radiolabeled kudzu hairy root cultures were extracted with 80% methanol, partitioned by solvent extraction, and then subfractionated by Sephadex LH-20 gel filtration. Radiolabeled isoflavones were isolated in a highly enriched fraction, which contained predominantly puerarin, daidzin and malonyl-daidzin and had an average radioactivity of 8.614 MBq/g (232.8 μCi/g) dry fraction. The (14)C-radiolabeled, isoflavone-rich fraction was orally administered at a dose of 60 mg/kg body weight to male Sprague-Dawley rats implanted with a jugular catheter, a subcutaneous ultrafiltrate probe and a brain microdialysate probe. Serum, interstitial fluid, brain microdialysate, urine and feces were collected using a Culex(®) Automated Blood Collection System for 24 h. At the end of this period, rats were sacrificed and major tissues were collected. Analysis by a scintillation counter confirmed that a bolus dose of (14)C-radiolabeled, isoflavone-rich kudzu fraction reached bone tissues, which accumulated 0.011%, 0.09% and 0.003% of the administered dose in femur, tibia and vertebrae, respectively. Femurs extracted with 80% methanol were analyzed by high-performance liquid chromatography with electrospray ionization-mass spectrometry and were found to contain trace quantities of puerarin, daidzein and puerarin glucuronide. This study demonstrates that kudzu isoflavones and metabolites are capable of reaching bone tissues, where they may contribute to the prevention of osteoporosis and the promotion of bone health.

Puerarin inhibits caspase-3 expression in osteoblasts of diabetic rats

“…Modern pharmacology has demonstrated that puerarin activates blood and eliminates stasis, improves micro-circulation and decreases blood glucose (25,26). Furthermore, it has been shown to have clinical applications in the treatment and management of diabetes, cardiovascular diseases and osteoporosis of post-menopausal women (27)(28)(29). In the present study, STZ-treated rats showed a decrease in femoral BMD compared to normal control rats.…”

Neutral Loss Ion Mapping Experiment Combined with Precursor Mass List and Dynamic Exclusion for Screening Unstable Malonyl Glucoside Conjugates

“…Some minor malonyl glycosides, such as malonyl daidzin and malonyl genistin, were also reported from Gegen in the past decades [19][20][21]. To our knowledge, there were no C-glycoside malonyl conjugates reported till now.…”

Vitamin D Interactions with Soy Isoflavones on Bone after Menopause: A Review

“…Furthermore, increasing levels of soy isoflavones had no effect on Ca absorption in postmenopausal women [44,45]. On the other hand, it has been shown that isoflavones reach the bone tissue [46]. Low-dose daidzein induced nucleus ERβ, while 17β-estrogen increased ERα in young piglet bone cells [47].…”