A biochanin-enriched isoflavone from red clover lowers LDL cholesterol in men

Abstract

Objective: To determine whether the two major isoflavones in red clover differ in their effect on low-density lipoprotein cholesterol (LDL-C). Design: A randomised, placebo-controlled, double-blind trial; two parallel groups taking one of the two isoflavones within which treatment and placebo were administered in a crossover design. Setting: Free-living volunteers. Subjects: A total of 46 middle-aged men and 34 postmenopausal women. Intervention: Two mixtures of red clover isoflavones enriched in either biochanin (n ¼ 40) or formononetin (n ¼ 40) were compared. Placebo and active treatment (40 mg/day) were administered for 6 weeks each in a crossover design within the two parallel groups. Main outcome measures: Plasma lipids were measured twice at the end of each period. Results: Baseline LDL-C concentrations did not differ significantly between men (n ¼ 46) and women (n ¼ 34), nor between those randomised to biochanin or formononetin. Interaction between time and treatments, biochanin, formononetin and corresponding placebos (two-way ANOVA) on LDL-C showed a significant effect of biochanin treatment alone. The biochanin effect was confined to men; median LDL-C was 3.61 (3.05-4.14) mmol/l with biochanin and 3.99 (3.16-4.29) mmol/l with the corresponding placebo (RM ANOVA with Dunnett's adjustment Po0.05). The difference between placebo and biochanin effects on LDL-C was 9.5%. No other lipid was affected and women failed to respond significantly to treatment. Conclusion: Isolated isoflavones from red clover enriched in biochanin (genistein precursor) but not in formononetin (daidzein precursor), lowered LDL-C in men. This may partly explain the previous failure to demonstrate cholesterol-lowering effects with mixed isoflavones studied predominantly in women.

Biochanin A Protects against Acute Carbon Tetrachloride-Induced Hepatotoxicity in Rats

“…In addition, they showed near-normal levels of lipid components (TC, TG) in the serum as compared to the hepatotoxicity model group, especially at the two higher doses, which indicates preservation of cellular integrity and also suggests an antilipidemic effect, which has already been reported for men. 21) On the other hand, CCl 4 caused severe hypoglycemia and depletion of serum total proteins, as compared to the control group, whereas BCA slowly normalized the TP level. It significantly reversed CCl 4 -induced hypoglycemia, which suggests that BCA plays a modulatory role in glucose homeostasis.…”

Red clover (Trifolium pratense L.) isoflavones: determination of concentrations by plant stage, flower colour, plant part and cultivar

“…However, although there are differences in isoflavone composition, the absorption in humans is quite similar from soy and red clover. 6 Owing to their phytoestrogenic nature, isoflavonoids have been considered to offer beneficial effects in the prevention of hormone-related cancers, 7,8 cardiovascular diseases 9 and osteoporosis 10 and to relieve menopausal symptoms. 3,11 As early as 50 years ago, Virtanen et al 12 demonstrated antifungal activity of compounds isolated from red clover.…”

Pharmacokinetics and bioavailability of the isoflavone biochanin A in rats

“…17 Isofl avone extracts from red clover with BCA as the major component have been shown to reduce the loss of lumbar spine bone mineral content and bone mineral density in women 18 and to lower the LDL cholesterol level in men. 19 These red clover isofl avone extracts, such as Promensil (Novogen Inc, Stamford, CT), are now also commercially available as dietary supplements for relieving postmenopausal symptoms such as hot fl ashes and bone loss and for maintaining men ' s prostate health. More recently, BCA and other fl avonoids have been shown by in vitro studies to be potent inhibitors of the effl ux transporters P-glycoprotein and breast cancer resistance protein, 20 , 21 which are important molecular mechanisms for both multidrug resistance and drug disposition, indicating the potential of this compound for drug interactions.…”