Diabetes mellitus (DM) is a metabolic disease caused by insulin resistance or insufficiency. If poorly managed, DM can lead to a range of complications, such as nephropathy, cardiovascular disease and diabetic retinopathy. The traditional Chinese medicine Radix Puerariae (PTIF), the dried root of Pueraria lobata, improves insulin responsiveness in diabetic rats when used as an adjuvant for metabolic disease. However, its therapeutic mechanism is unclear. Zhang et al. (2016) used a metabolomics approach to investigate the effects of total isoflavones extracted from PTIF in diabetic rats.
The investigators used two groups of healthy adult male mice: a control group and a group with a high-fat diet. They fed the rats their respective diets for six weeks. At this point, the group with the high-fat diet received an intraperitoneal injection of a single dose of streptozotocin (STZ), and the control group received a solution of citric acid–sodium citrate buffer only. Zhang et al. then fed the STZ rats a normal diet. Those with blood glucose levels greater than or equal to 16.7 mmol/l 72 hours after the administration of STZ were considered to be diabetic. They then split the diabetic group in half, and from 26 weeks they administered PTIF to one group. After 10 weeks, they extracted plasma and serum samples from each rat.
Compared with the control group, STZ treatment resulted in a significant decrease in body weight and induced a sustained high blood glucose level. Rats in the diabetic + PTIF group showed a significant increase in body weight at weeks 34 and 36 but no significant difference in blood glucose with PTIF treatment. PTIF also had no significant effect on inflammatory cytokines. The investigators analyzed plasma samples using ultra-performance liquid chromatography and a Q Exactive mass spectrometer (Thermo Scientific). They found changes to the plasma metabolic fingerprint in STZ-treated rats, and that administering PTIF gradually restored the biochemical changes in model rats to normal. They suggest this indicates that PTIF is effective for improving metabolism disorders in STZ-induced diabetic rats.
Using the raw mass spectrometry data, Zhang et al. identified 11 potential metabolite biomarkers and analyzed their functional pathways. They found that PTIF partially ameliorates coagulopathy and thus has a therapeutic influence on DM. Furthermore, 5′-methylthioadenosine, Lys-Lys-Ser, Leu-Ser-Lys-Lys and Gly-His-Arg-Gly were significantly increased in model rats, suggesting that PTIF was beneficial to regulating the amino acid metabolism disorders.
Ultimately, Zhang et al. demonstrated an effective metabolomics method confirming that PTIF has a protective effect with great therapeutic potential for treating DM by inhibiting oxidative damage.
1. Zhang, Y., et al. (2016) “Metabolic analysis of biochemical changes in the plasma of high-fat diet and streptozotocin-induced diabetic rats after treatment with isoflavones extract of Radix Puerariae,” Evidence-Based Complementary and Alternative Medicine, doi: 10.1155/2016/4701890.
Post Author: Miriam Pollak. Miriam a Nutritionist specialising in women’s health and works from her Bondi Beach clinic. She is also currently completing her Masters by research in nutrition. Prior to this, Miriam majored in neuroscience as an undergraduate before completing a post graduate degree in science communication. She spent over a decade working in science communication and medical research, collaborating with some of the best oncologists and researchers in Australia and the U.S.
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