Kudzu root: an ancient Chinese source of modern antidipsotropic agents

Separation and purification of puerarin using β-cyclodextrin-coupled agarose gel media

The isoflavonoid puerarin, a well-known traditional Chinese drug, has been purified in one step from an extract of Radix puerariae (root of the plant Pueralria lobata) by adsorption chromatography on an epichlorohydrin polymerized beta-cyclodextrin ligand coupled to brominated allyl-group substituted Sepharose HP. Acetic acid (10%) was used as the mobile phase and the optimum loading capacity was around 1.2 mg crude extract/ml packed gel. The purity of the collected puerarin was about 98% with a recovery of about 62%.

Synthesis of daidzin analogues as potential agents for alcohol abuse

Daidzin, the active principle of an herbal remedy for 'alcohol addiction', has been shown to reduce alcohol consumption in all laboratory animals tested to date. Correlation studies using structural analogues of daidzin suggests that it acts by raising the monoamine oxidase (MAO)/mitochondrial aldehyde dehydrogenase (ALDH-2) activity ratio (J. Med. Chem. 2000, 43, 4169). Structure-activity relationship (SAR) studies on the 7-O-substituted analogues of daidzin have revealed structural features important for ALDH-2 and MAO inhibition (J. Med. Chem. 2001, 44, 3320). We here evaluated effects of substitutions at 2, 5, 6, 8, 3' and 4' positions of daidzin on its potencies for ALDH-2 and MAO inhibition. Results show that analogues with 4'-substituents that are small, polar and with hydrogen bonding capacities are most potent ALDH-2 inhibitors, whereas those that are non-polar and with electron withdrawing capacities are potent MAO inhibitors. Analogues with a 5-OH group are less potent ALDH-2 inhibitors but are more potent MAO inhibitors. All the 2-, 6-, 8- and 3'-substituted analogues tested so far do not inhibit ALDH-2 and/or have decreased potencies for MAO inhibition. This, together with the results obtained from previous studies, suggests that a potent antidipsotropic analogue would be a 4',7-disubstituted isoflavone. The 4'-substituent should be small, polar, and with hydrogen bonding capacities such as, -OH and -NH(2); whereas the 7-substituent should be a straight-chain alkyl with a terminal polar function such as -(CH(2))(n)-OH with 2< or =n < or =6, -(CH(2))(n)-COOH with 5< or =n < or =10, or -(CH(2))(n)-NH(2) with n > or =4.

Profiling and quantification of isoflavonoids in kudzu dietary supplements by high-performance liquid chromatography and electrospray ionization tandem mass spectrometry

The kudzu vine (Pueraria sp.) is a rich source of isoflavones. Dietary supplements based on kudzu have become commercially available. In the present study, liquid chromatography coupled with negative and positive electrospray ionization tandem mass spectrometry (MS/MS) and diode array detection (DAD) has been used for the detection and characterization of isoflavonoids in kudzu dietary supplements (KDS). The MS/MS spectrum of the protonated ion of puerarin showed characteristic product ions of the C-glycoside unit itself, whereas daidzin generated an abundant Y(0)(+) aglycon ion in its product ion spectrum. A base peak due to the loss of 120 Da [M + H - 120](+) is the diagnostic ion for C-glycosides. Neutral loss scans allowed for the detection of other C- and O-glycosides in the methanolic extract of KDS, and their structures have been proposed. The concentration of isoflavonoids in the methanolic extract of commercially available KDS was quantified by using DAD-HPLC. Puerarin, rather than daidzin, was the most abundant component (8.44-30.60 mg/capsule) in commercially available KDS.

The effect of Puerariae radix on lipoprotein metabolism in liver and intestinal cells

BACKGROUND

Animal studies investigating the beneficial effects of Puerariae radix on cardiovascular disease have suggested this plant possesses anti-diabetic and lipid lowering properties. However, the exact mechanism by which Puerariae radix affects lipid metabolism is currently unknown. The aim of this study was to investigate the effect of the water extract of Puerariae radix on the secretion of VLDL and chylomicrons from HepG2 liver cells and CaCo2 cells, respectively, in humans.

METHODS

The amount of apoB100 (a protein marker for VLDL) and apoB48 (a protein marker for chylomicrons) in cells and media were quantified by Western Blotting and enhanced chemiluminescence (ECL). Total, free and esterified cholesterol concentrations were measured by gas liquid chromatography.

RESULTS

Treatment of cells with water extract of Puerariae radix significantly decreased apoB100 production and secretion from HepG2 cells up to 66% in a dose dependent manner. The intracellular total cholesterol and free cholesterol concentration in HepG2 cells also decreased with increasing concentration of the Puerariae radix. In contrast, water extract of Puerariae radix attenuated apoB48 concentrations in cells, but not apoB48 secretion from CaCo2 enterocytes.

CONCLUSIONS

Collectively, our findings suggest that the water extract of Puerariae radix attenuates the hepatic lipoprotein production and secretion. Our present cell culture findings may explain why circulating VLDL and LDL levels were attenuated in animals supplemented with Puerariae radix. Since decreasing the production and secretion of atherogenic lipoproteins decreases the risk of development of cardiovascular disease, diets supplemented with radix may provide a safe and effective beneficial cardioprotective effects in humans.

Toxicity study of an antidipsotropic Chinese herbal mixture in rats: NPI-028

OBJECTIVES

To determine the potential toxicity and safety of the Chinese herbal medicine NPI-028 in rats following subchronic (3-month) exposure via daily oral consumption.

DESIGN

Subchronic toxicity was evaluated in four groups of rats (n = 10 per group) receiving NPI-028 orally at a dose of either 0.0 (normal diet control), 0.5, 1.0, or 2.0 g/kg, ingested as part of their daily diet for 3 months. NPI-028 was incorporated into powdered rat chow diet as a specific percent of the total diet provided each day. The primary active isoflavone content of NPI-028 (puerarin) used in the rat diet was also determined.

OUTCOME MEASURES

Subchronic toxicity was assessed over a 3-month period by biweekly measurement of water and food intake, weight gain, and visual inspection for maintenance of grooming and normal behavior. At the end of the study period rats were euthanized and blood was obtained for hematologic and chemical analysis. Organs were removed for histopathologic examination.

RESULTS

Rats in all three NPI-028 dose groups were similar to the control group in weight gain, food intake, and water intake over the study period. Hematology, blood chemistries, and organ histology in rats at all three NPI-028 doses did not significantly differ from control rats. Minor exceptions were elevated urea nitrogen values at all NPI-028 doses, and increased triglyceride and thyroid-stimulating hormone values in the lowest NPI-028 dose-treated group. Puerarin (used as a dietary isoflavone marker) content of NPI-028 was 26 mg/g dry weight.

CONCLUSIONS

NPI-028 ingested orally at doses up to 2.0 g/kg per day in the rat diet for up to 3 months resulted in normal growth with no changes in hematologic or hepatic parameters, and only minor alterations in renal and blood chemistry parameters. There was no evidence of abnormal histology. These data suggest the long-term daily oral consumption of NPI-028 as a part of the daily diet for 3 months, at the doses studied, is safe in rats. Thus, NPI-028 may potentially be safe for clinical use as an antidipsotropic agent.

Protective effects of puerariaeflos against ethanol-induced apoptosis on human neuroblastoma cell line SK-N-MC

Puerariaeflos (PF) is an oriental medical herb for alcohol abuse. To investigate whether PF possesses protective effects against ethanol (EtOH)-induced cytotoxicity in the central nervous system, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometric analysis, DNA fragmentation assay, and reverse transcription-polymerase chain reaction were performed on SK-N-MC human neuroblastoma cells. Cells treated with EtOH exhibited several apoptotic features, while those pre-treated with PF prior to EtOH exposure showed a decreased occurrence of apoptotic features. In addition, PF pre-treatment inhibited the EtOH-induced increase in caspase-3 mRNA expression. These results suggest that PF may exert protective effects against EtOH-induced apoptosis in human neuroblastoma cells.

Bioavailability of pure isoflavones in healthy humans and analysis of commercial soy isoflavone supplements

The pharmacokinetic behavior of naturally occurring isoflavones has been determined for the first time in healthy adults. We compared plasma kinetics of pure daidzein, genistein and their beta-glycosides administered as a single-bolus dose to 19 healthy women. This study demonstrates differences in the pharmacokinetics of isoflavone glycosides compared with their respective beta-glycosides. Although all isoflavones are efficiently absorbed from the intestinal tract, there are striking differences in the fate of aglycones and beta-glycosides. Mean time to attain peak plasma concentrations (t(max)) for the aglycones genistein and daidzein was 5.2 and 6.6 h, respectively, whereas for the corresponding beta-glycosides, the t(max) was delayed to 9.3 and 9.0 h, respectively, consistent with the residence time needed for hydrolytic cleavage of the glycoside moiety for bioavailability. The apparent volume of distribution of isoflavones confirms extensive tissue distribution after absorption. Plasma genistein concentrations are consistently higher than daidzein when equal amounts of the two isoflavones are administered, and this is accounted for by the more extensive distribution of daidzein (236 L) compared with genistein (161 L). The systemic bioavailability of genistein [mean AUC = 4.54 microg/(mL x h)] is much greater than that of daidzein [mean AUC = 2.94 microg/(mL x h)], and bioavailability of these isoflavones is greater when ingested as beta-glycosides rather than aglycones as measured from the area under the curve of the plasma appearance and disappearance concentrations. The pharmacokinetics of methoxylated isoflavones show distinct differences depending on the position of the methoxyl group in the molecule. Glycitin, found in two phytoestrogen supplements, underwent hydrolysis of the beta-glycoside moiety and little further biotransformation, leading to high plasma glycitein concentrations. Biochanin A and formononetin, two isoflavones found in one phytoestrogen supplement, were rapidly and efficiently demethylated, resulting in high plasma genistein and daidzein concentrations typically observed after the ingestion of soy-containing foods. These differences in pharmacokinetics and metabolism have implications for clinical studies because it cannot be assumed that all isoflavones are comparable in their pharmacokinetics and bioavailability. An analysis of 33 phytoestrogen supplements and extracts revealed considerable differences in the isoflavone content from that claimed by the manufacturers. Plasma concentrations of isoflavones show marked qualitative and quantitative differences depending on the type of supplement ingested. These studies indicate a need for improvement in quality assurance and standardization of such products.

Volitional ethanol consumption affects overall serotonin metabolism in Syrian golden hamsters (Mesocricetus auratus)

Methods were established for the determination of serotonin (5-HT)(1) metabolites 5-hydroxyindole-3-acetic acid (5-HIAA) and 5-hydroxytryptophol (5-HTOL) in the urine of Syrian golden hamsters (Mesocricetus auratus) and used to study the effect of volitional ethanol consumption on overall 5-HT metabolism in this ethanol-preferring rodent. The basal levels of 5-HIAA and 5-HTOL in 24-h urine of ethanol-naive hamsters were 300 +/- 101 and 4.96 +/- 1. 06 nmol (n = 8), respectively. Given free choice between water and a 15% ethanol solution, these hamsters chose to consume increasing amounts of ethanol. The increase was accompanied by a concomitant decrease in urine 5-HIAA and increase in urine 5-HTOL, indicating that volitional ethanol intake diverted part of the 5-HT metabolic flux from an oxidative into a reductive pathway. In a separate experiment, the amounts of ethanol consumed by and blood ethanol concentrations attained in ethanol-drinking golden hamsters were determined at 5 different time intervals between 6 PM and 7 AM when most feeding activities occurred. Except in the first hour after lights were turned off, ethanol was consumed at a relatively even pace throughout the night (2-3 g/kg/3 h) and blood ethanol levels were maintained at the low mM range which rarely exceeded 2 mM. These results suggest that the biochemical pathway that catalyzes 5-HT metabolism is extremely sensitive to ethanol and can play an important role in mediating the reported clinically beneficial action of a low concentration of ethanol during alcohol detoxification.

A pilot study exploring the effect of kudzu root on the drinking habits of patients with chronic alcoholism

PURPOSE

The objective of this study was to assess if kudzu root extract influences the drinking habits of veterans who entered a substance abuse treatment program.

DESIGN

Prospective, randomized double-blind controlled clinical trial.

SETTING

A nonacademic Veteran Affairs Medical Center.

METHODS

Patients with the diagnosis of alcoholism were randomly assigned to receive either kudzu root extract 1.2 g twice daily or a matching placebo. Patients completed questionnaires that focused on craving for alcohol and sobriety status on a monthly basis.

OUTCOME MEASURES

Sobriety level and craving for ethanol were assessed on a visual analogue scale from 0 to 10.

RESULTS

Thirty-eight patients completed 1 month of the study; 21 randomly assigned kudzu, 17 to placebo. No statistically significance difference in craving and sobriety scores were noted after 1 month between kudzu and placebo, or at later stages with smaller numbers (15-19) of patients.

CONCLUSION

In this small patient population, kudzu root appeared to be no better than placebo in reducing the craving for alcohol or promoting sobriety.

Rational treatment of addiction

Treatment of alcohol and drug addictions, which has been neglected medically for a long time, is currently sparked with optimism. Craving for alcohol can be treated with two newly registered drugs: naltrexone and acamprosate. New approaches to symptom relief during detoxification or during maintenance therapies are rationally based on experimental and clinical work. It is now clear that addictive drugs are surrogates of natural substances involved in the 'reward system'.