Further studies on the mechanism of the mineralocorticoid action of licorice in humans

A low dose of daily licorice intake affects renin, aldosterone, and home blood pressure in a randomized crossover trial

BACKGROUND

Licorice, through the effects of glycyrrhizic acid (GA), raises blood pressure (BP). The World Health Organization has suggested that 100 mg GA/d would be unlikely to cause adverse effects, but of 13 previously published studies none have been randomized and controlled and independently quantified the GA content.

OBJECTIVE

Our aim was to analyze the effects on home BP of a daily licorice intake containing 100 mg GA.

METHODS

Healthy volunteers were randomly assigned to start with either licorice or a control product in a nonblinded, 2 × 2 crossover study. Home BP was measured daily, and blood samples were collected at the end of each 2-wk period.

RESULTS

There were 28 participants and no dropouts. The median age was 24.0 y (interquartile range 22.8-27.0 y). During the licorice compared with control intake period, the systolic home BP increased [mean difference: 3.1 mm Hg (95% confidence interval [CI]: 0.8, 5.4 mm Hg) compared with -0.3 mm Hg (95% CI: -1.8, 1.3 mm Hg); P = 0.018] and renin and aldosterone were suppressed [mean change: -30.0% (95% CI: -56.7%, -3.3%) compared with 15.8% (95% CI: -12.8%, 44.4%); P = 0.003; and -45.1% (95% CI: -61.5%, -28.7%) compared with 8.2% (95% CI: -14.7%, 31.1%); P <0.001, respectively]. In the quartile of participants with the most pronounced suppression of renin and aldosterone, N-terminal prohormone of brain natriuretic peptide concentration increased during the licorice compared with control period [mean change: 204.1% (95% CI: -11.6%, 419.7%) compared with 72.4% (95% CI: -52.2%, 197.1%); P = 0.016].

CONCLUSIONS

We found licorice to be more potent than previously known, with significant increases in BP, after a daily intake of only 100 mg GA. Thus, the safe limit of intake of this substance might need to be reconsidered. This trial was registered at clinicaltrials.gov as NCT05661721 (https://clinicaltrials.gov/study/NCT05661721).

Licorice metabolite 18β-glycyrrhetinic acid activates G protein-gated inwardly rectifying K+ channels

BACKGROUND AND PURPOSE

Licorice (liquorice) is a common food additive and is used in Chinese medicine. Excess licorice intake can induce atrial fibrillation. Patients with atrial fibrillation possess constitutively activated G protein-gated inwardly rectifying K+ (GIRK) channels. Whether licorice affects GIRK channel activity is unknown. We aimed to clarify the effects of licorice ingredients on GIRK current and the mechanism of action.

EXPERIMENTAL APPROACH

A major component of licorice, glycyrrhizic acid (GA), and its metabolite, 18β-glycyrrhetinic acid (18β-GA), were tested. We performed electrophysiological recordings in Xenopus oocytes to examine the effects of GA and 18β-GA on various GIRK subunits (Kir 3.1-Kir 3.4), mutagenesis analyses to identify the crucial residues for drug action and motion analysis in cultured rat atrial myocytes to clarify effects of 18β-GA on atrial functions.

KEY RESULTS

GA inhibited Kir 3.1-containing channels, while 18β-GA activated all Kir 3.x subunits. A pore helix residue Phe137 in Kir 3.1 was critical for GA-mediated inhibition, and the corresponding Ser148 in Kir 3.2 was critical for 18β-GA-mediated activation. 18β-GA activated GIRK channel in a Gβγ -independent manner, whereas phosphatidylinositol 4,5-bisphosphate (PIP2 ) was essential for activation. Glu236 located at the cytoplasmic pore of Kir 3.2 appeared to be important to interactions with 18β-GA. In rat atrial myocytes, 18β-GA suppressed spontaneous beating via activation of GIRK channels.

CONCLUSION AND IMPLICATIONS

GA acts as a novel GIRK inhibitor, and 18β-GA acts as a novel GIRK activator. 18β-GA alters atrial function via activation of GIRK channels. This study elucidates the pharmacological activity of licorice ingredients and provides information for drug design.

Revisiting Licorice as a functional food in the management of neurological disorders: Bench to trend

Traditional and scientific evidence attribute numerous bioactivities of Licorice (Glycyrrhiza glabra Linn.) in aging-related disorders. In this state-of-art review, an extensive search in several databases was conducted to collect all relevant literature and comprehensively analyze Licorice's pharmacological attributes, neuroprotective properties, safety, and its mechanistic role in treating various neurological conditions. Network pharmacology was employed for the first time exploring the mechanistic role of Licorice in neurological disorders. Its neuroprotective role is attributed to phytoconstituents, including liquiritin, glycyrrhizic acid, liquiritigenin, glabridin, 18ß-glycyrrhetinic acid, quercetin, isoliquiritigenin, paratocarpin B, glycyglabrone, and hispaglabridin B, as evident from in vitro and in vivo studies. Network pharmacology analysis reveals that these compounds protect against long-term depression, aging-associated diseases, Alzheimer's disease, and other addictions through interactions with cholinergic, dopaminergic, and serotonergic proteins, validated in animal studies only. Future clinical trials are warranted as Licorice administration has a limiting factor of mild hypertension and hypokalemia. Hopefully, scientific updates on Licorice will propagate a paradigm shift in medicine, research propagation, and development of the central nervous system phytopharmaceuticals.

A viewpoint on aldosterone and BMI related brain morphology in relation to treatment outcome in patients with major depression

An abundance of knowledge has been collected describing the involvement of neuroendocrine parameters in major depression. The hypothalamic-pituitary-adrenocortical (HPA) axis regulating cortisol release has been extensively studied; however, attempts to target the HPA axis pharmacologically to treat major depression have failed. This review focuses on the importance of the adrenocortical stress hormone aldosterone, which is released by adrenocorticotropic hormone and angiotensin, and the mineralocorticoid receptor (MR) in depression. Depressed patients, in particular those with atypical depression, have signs of central hyperactivation of the aldosterone sensitive MR, potentially as a consequence of a reactive aldosterone release induced by low blood pressure and as a result of low sensitivity of peripheral MR. This is reflected in reduced heart rate variability, increased salt appetite and sleep changes in this group of patients. In addition, enlarged brain ventricles, compressed corpus callosum and changes of the choroid plexus are associated with increased aldosterone (in relation to cortisol). Furthermore, subjects with these features often show obesity. These characteristics are related to a worse antidepressant treatment outcome. Alterations in choroid plexus function as a consequence of increased aldosterone levels, autonomic dysregulation, metabolic changes and/or inflammation may be involved. The characterization of this regulatory system is in its early days but may identify new targets for therapeutic interventions.

Glycyrrhetinic acid: a promising scaffold for the discovery of anticancer agents

INTRODUCTION

Oleanane-type pentacyclic triterpenes named glycyrrhetinic acids (GAs) featuring a C-30 carboxylic acid group, are extracted from the licorice (Glycyrrhiza uralensis). Numerous biological properties of GA have been reported and have attracted researchers from all over the world in recent years due to the peculiar GA scaffold-based semisynthetic cytotoxic effects.

AREAS COVERED

This review represents the applications of semisynthetic derivatives of GA for the development of future cancer treatments. Included in the review are important structural features of the semisynthetic GAs crucial for cytotoxic effects.

EXPERT OPINION

Numerous semisynthetic GA derivatives illustrated excellent cytotoxic effects toward various cancer cells. Notably the C-₃(OH) at ring A along with C_30-CO₂H at ring E as vital structural features, make GA very appealing as a lead scaffold for medicinal chemistry, since these two groups permit the creation of further chemical diversity geared toward improved cytotoxic effects. Furthermore, numerous GA derivatives have been synthesized and indicate that compounds featuring cyanoenone moieties in ring A, or compounds having the amino group or nitrogen comprising heterocycles and hybrids thereof, illustrate more potent cytotoxicity. Furthermore, GA has a great capability to be conjugated with other anticancer molecules to synergistically enhance their combined cytotoxicity.

Food Enrichment with Glycyrrhiza glabra Extract Suppresses ACE2 mRNA and Protein Expression in Rats-Possible Implications for COVID-19

Angiotensin converting enzyme 2 (ACE2) is a key entry point of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus known to induce Coronavirus disease 2019 (COVID-19). We have recently outlined a concept to reduce ACE2 expression by the administration of glycyrrhizin, a component of Glycyrrhiza glabra extract, via its inhibitory activity on 11beta hydroxysteroid dehydrogenase type 2 (11betaHSD2) and resulting activation of mineralocorticoid receptor (MR). We hypothesized that in organs such as the ileum, which co-express 11betaHSD2, MR and ACE2, the expression of ACE2 would be suppressed. We studied organ tissues from an experiment originally designed to address the effects of Glycyrrhiza glabra extract on stress response. Male Sprague Dawley rats were left undisturbed or exposed to chronic mild stress for five weeks. For the last two weeks, animals continued with a placebo diet or received a diet containing extract of Glycyrrhiza glabra root at a dose of 150 mg/kg of body weight/day. Quantitative PCR measurements showed a significant decrease in gene expression of ACE2 in the small intestine of rats fed with diet containing Glycyrrhiza glabra extract. This effect was independent of the stress condition and failed to be observed in non-target tissues, namely the heart and the brain cortex. In the small intestine we also confirmed the reduction of ACE2 at the protein level. Present findings provide evidence to support the hypothesis that Glycyrrhiza glabra extract may reduce an entry point of SARS-CoV-2. Whether this phenomenon, when confirmed in additional studies, is linked to the susceptibility of cells to the virus requires further studies.

Preclinical Evidence for the Pharmacological Actions of Glycyrrhizic Acid: A Comprehensive Review

Glycyrrhiza glabra L. (Family: Fabaceae) is one of the important traditional medicinal plant used extensively in folk medicine. It is known for its ethnopharmacological value in curing a wide variety of ailments. Glycyrrhizin, an active compound of G. glabra, possesses anti-inflammatory activity due to which it is mostly used in traditional herbal medicine for the treatment and management of chronic diseases. The present review is focused extensively on the pharmacology, pharmacokinetics, toxicology, and potential effects of Glycyrrhizic Acid (GA). A thorough literature survey was conducted to identify various studies that reported on the GA on PubMed, Science Direct and Google Scholar.

Adjunct Therapy With Glycyrrhiza Glabra Rapidly Improves Outcome in Depression-A Pilot Study to Support 11-Beta-Hydroxysteroid Dehydrogenase Type 2 Inhibition as a New Target

Mineralocorticoid-receptor (MR) dysfunction as expressed by low systolic blood pressure and a high salivary aldosterone/cortisol ratio predicts less favorable antidepressant treatment outcome. Inhibition of peripheral 11-beta-hydroxysteroid-dehydrogenase type 2 (11betaHSD2) reverses these markers. We therefore tested the hypothesis that the 11betaHSD2 inhibitor glycyrrhizin affects treatment outcome via this mechanism. We administered Glycyrrhiza glabra (GG) extract containing 7-8 % of glycyrrhizin at a dose of 2 × 700 mg daily adjunct to standard antidepressants in hospitalized patients with major depression. These subjects were compared in an open-label fashion with patients, who did not receive GG (treatment as usual, TAU). Assessments were done at baseline and approximately 2 weeks after. Twelve subjects were treated with GG and compared to 55 subjects with TAU. At week 2, the Hamilton Depression Rating Scale (HAMD-21) change from baseline as well as the CGI-S change showed a significant time × treatment interaction (p < 0.03), indicating a possible therapeutic benefit of GG. Clinical benefit seems to be more pronounced in subjects with lower systolic blood pressure and significantly correlated with reduced sleep duration in the GG group. Our preliminary data show that treatment with the 11betaHSD2 inhibitor glycyrrhizin may possess a beneficial effect on antidepressant response, which may be specific to a defined depression subtype.

Bioactive Candy: Effects of Licorice on the Cardiovascular System

Licorice, today chiefly utilized as a flavoring additive in tea, tobacco and candy, is one of the oldest used herbs for medicinal purposes and consists of up to 300 active compounds. The main active constituent of licorice is the prodrug glycyrrhizin, which is successively converted to 3β-monoglucuronyl-18β-glycyrrhetinic acid (3MGA) and 18β-glycyrrhetinic acid (GA) in the intestines. Despite many reported health benefits, 3MGA and GA inhibit the 11-β-hydrogenase type II enzyme (11β-HSD2) oxidizing cortisol to cortisone. Through activation of mineralocorticoid receptors, high cortisol levels induce a mild form of apparent mineralocorticoid excess in the kidney and increase systemic vascular resistance. Continuous inhibition of 11β-HSD2 related to excess licorice consumption will create a state of hypernatremia, hypokalemia and increased fluid volume, which can cause serious life-threatening complications especially in patients already suffering from cardiovascular diseases. Two recent meta-analyses of 18 and 26 studies investigating the correlation between licorice intake and blood pressure revealed statistically significant increases both in systolic (5.45 mmHg) and in diastolic blood pressure (3.19/1.74 mmHg). This review summarizes and evaluates current literature about the acute and chronic effects of licorice ingestion on the cardiovascular system with special focus on blood pressure. Starting from the molecular actions of licorice (metabolites) inside the cells, it describes how licorice intake is affecting the human body and shows the boundaries between the health benefits of licorice and possible harmful effects.

Aldosterone in Gynecology and Its Involvement on the Risk of Hypertension in Pregnancy

Aldosterone is the main mineralocorticoid hormone, responsible of the regulation of fluid and electrolyte balance and blood pressure. It acts also as a pro-inflammatory factor responsible of an increased cardiovascular risk, independent from blood pressure values. After the discovery of mineralocorticoid receptor (MR) in mononuclear leukocytes, further studies supported its role in inflammatory and even autoimmune mechanisms underlying several diseases. In particular, recent studies reported a possible involvement of aldosterone in some gynecological conditions and diseases, characterized by inflammation, hypertension and increased cardio-metabolic risk, such as use of hormonal contraceptives, preeclampsia, polycystic ovary syndrome, uterine fibroids, and endometriosis. The aim of this mini-review is to report the possible involvement of aldosterone in all these gynecological conditions, suggesting different pathogenetic mechanisms and new target treatments of MR blockers for these diseases.

Licorice: From Pseudohyperaldosteronism to Therapeutic Uses

Licorice has been used as a medicinal plant from 2.500 years. It shows a wide range of biological and pharmacological activities, including anti-inflammatory and immune regulatory actions. One of its most known effects is the induction of hypertension, and it can induce what appears to be pseudohyperaldosteronism, due to glycyrrhetinic acid, the main active component of the root. Glycyrrhetinic acid and metabolites block the 11 beta-hydroxysteroid dehydrogenase type 2 and also bind mineralocorticoid receptors directly, acting as agonists. However, other interesting therapeutic uses of licorice are linked to its anti-androgen and estrogen-like activity, especially in the treatment of polycystic ovary syndrome (PCOS) in conjunction with spironolactone therapy. In this brief review, we report the main features and possible therapeutic uses of this ancient plant.

Saponins as modulators of nuclear receptors

As plant-derived natural products, saponins have been widely applied for the dietary modification of metabolic syndrome. However, the underlying mechanisms of their preventive and therapeutic effects are still largely unclear. Nuclear receptors have been identified as potential pharmaceutical targets for treating various types of metabolic disorders. With similar structure to endogenous hormones, several saponins may serve as selective ligands for nuclear receptors. Recently, a series of saponins are proved to exert their physiological activities through binding to nuclear receptors. This review summarizes the biological and pharmacological activities of typical saponins mediated by some of the most well described nuclear receptors, including the classical steroid hormone receptors (ER, GR, MR, and AR) and the adopted orphan receptors (PPAR, LXR, FXR, and PXR).

The association between consistent licorice ingestion, hypertension and hypokalaemia: a systematic review and meta-analysis

There have been numerous case reports of severe adverse events including deaths following chronic licorice ingestion. The aim of the present study was to evaluate the effect of chronic ingestion of licorice on blood pressure, plasma potassium, plasma renin activity and plasma aldosterone. A search of MEDLINE, PubMed, EMBASE, CENTRAL, DARE, CINAHL and Current Contents Connect was performed from inception through to 26 April 2017. Trials that included a treatment group ingesting a product containing at least 100 mg of glycyrrhizic acid daily were selected. Pooled mean changes from baseline with 95% confidence intervals were calculated for diastolic blood pressure, systolic blood pressure, plasma potassium, plasma renin activity and plasma aldosterone using a random effects model. An assessment of dose-response was also undertaken. A total of 18 studies (n=337) were included in the meta-analysis. There was a statistically significant increase in mean systolic blood pressure (5.45 mm Hg, 95% CI 3.51-7.39) and diastolic blood pressure (3.19 mm Hg, 95% CI 0.10-6.29) after chronic ingestion of a product containing glycyrrhizic acid. Plasma potassium (-0.33 mmol l-1, 95% CI -0.42 to 0.23), plasma renin activity (-0.82 ngml-1 per hour, 95% CI -1.27 to -0.37) and plasma aldosterone (-173.24 pmol l-1, 95% CI -231.65 to -114.83) were all significantly decreased. A significant correlation was noted between daily dose of glycyrrhizic acid and systolic blood pressure (r2=0.55) and diastolic blood pressure (r2=0.65), but not for the other outcome measures. Hence, chronic licorice ingestion is associated with an increase in blood pressure and a drop in plasma potassium, even at modest doses. This is of particular relevance for individuals with existing cardiovascular disease.

Syndromes that Mimic an Excess of Mineralocorticoids

Pseudohyperaldosteronism is characterized by a clinical picture of hyperaldosteronism with suppression of renin and aldosterone. It can be due to endogenous or exogenous substances that mimic the effector mechanisms of aldosterone, leading not only to alterations of electrolytes and hypertension, but also to an increased inflammatory reaction in several tissues. Enzymatic defects of adrenal steroidogenesis (deficiency of 17α-hydroxylase and 11β-hydroxylase), mutations of mineralocorticoid receptor (MR) and alterations of expression or saturation of 11-hydroxysteroid dehydrogenase type 2 (apparent mineralocorticoid excess syndrome, Cushing's syndrome, excessive intake of licorice, grapefruits or carbenoxolone) are the main causes of pseudohyperaldosteronism. In these cases treatment with dexamethasone and/or MR-blockers is useful not only to normalize blood pressure and electrolytes, but also to prevent the deleterious effects of prolonged over-activation of MR in epithelial and non-epithelial tissues. Genetic alterations of the sodium channel (Liddle's syndrome) or of the sodium-chloride co-transporter (Gordon's syndrome) cause abnormal sodium and water reabsorption in the distal renal tubules and hypertension. Treatment with amiloride and thiazide diuretics can respectively reverse the clinical picture and the renin aldosterone system. Finally, many other more common situations can lead to an acquired pseudohyperaldosteronism, like the expansion of volume due to exaggerated water and/or sodium intake, and the use of drugs, as contraceptives, corticosteroids, β-adrenergic agonists and FANS. In conclusion, syndromes or situations that mimic aldosterone excess are not rare and an accurate personal and pharmacological history is mandatory for a correct diagnosis and avoiding unnecessary tests and mistreatments.

Glycyrrhiza glabra

Liquorice foliage

Adverse effects of plant food supplements and botanical preparations: a systematic review with critical evaluation of causality

AIMS

The objective of this review was to collect available data on the following: (i) adverse effects observed in humans from the intake of plant food supplements or botanical preparations; (ii) the misidentification of poisonous plants; and (iii) interactions between plant food supplements/botanicals and conventional drugs or nutrients.

METHODS

PubMed/MEDLINE and Embase were searched from database inception to June 2014, using the terms 'adverse effect/s', 'poisoning/s', 'plant food supplement/s', 'misidentification/s' and 'interaction/s' in combination with the relevant plant name. All papers were critically evaluated according to the World Health Organization Guidelines for causality assessment.

RESULTS

Data were obtained for 66 plants that are common ingredients of plant food supplements; of the 492 papers selected, 402 (81.7%) dealt with adverse effects directly associated with the botanical and 89 (18.1%) concerned interactions with conventional drugs. Only one case was associated with misidentification. Adverse effects were reported for 39 of the 66 botanical substances searched. Of the total references, 86.6% were associated with 14 plants, including Glycine max/soybean (19.3%), Glycyrrhiza glabra/liquorice (12.2%), Camellia sinensis/green tea ( 8.7%) and Ginkgo biloba/gingko (8.5%).

CONCLUSIONS

Considering the length of time examined and the number of plants included in the review, it is remarkable that: (i) the adverse effects due to botanical ingredients were relatively infrequent, if assessed for causality; and (ii) the number of severe clinical reactions was very limited, but some fatal cases have been described. Data presented in this review were assessed for quality in order to make the results maximally useful for clinicians in identifying or excluding deleterious effects of botanicals.

Glycyrrhizic acid can attenuate metabolic deviations caused by a high-sucrose diet without causing water retention in male Sprague-Dawley rats

Glycyrrhizic acid (GA) ameliorates many components of the metabolic syndrome, but its potential therapeutic use is marred by edema caused by inhibition of renal 11β-hydroxysteroid dehydrogenase 2 (11β-HSD2). We assessed whether 100 mg/kg per day GA administered orally could promote metabolic benefits without causing edema in rats fed on a high-sucrose diet. Groups of eight male rats were fed on one of three diets for 28 days: normal diet, a high-sucrose diet, or a high-sucrose diet supplemented with GA. Rats were then culled and renal 11β-HSD2 activity, as well as serum sodium, potassium, angiotensin II and leptin levels were determined. Histological analyses were performed to assess changes in adipocyte size in visceral and subcutaneous depots, as well as hepatic and renal tissue morphology. This dosing paradigm of GA attenuated the increases in serum leptin levels and visceral, but not subcutaneous adipocyte size caused by the high-sucrose diet. Although GA decreased renal 11β-HSD2 activity, it did not affect serum electrolyte or angiotensin II levels, indicating no onset of edema. Furthermore, there were no apparent morphological changes in the liver or kidney, indicating no toxicity. In conclusion, it is possible to reap metabolic benefits of GA without edema using the current dosage and treatment time.

Lethal liquorice lollies (liquorice abuse causing pseudohyperaldosteronism)

A 47-year-old woman was admitted to the emergency department with a history of asthenia, periorbital and lower limbs oedema, associated with hypokalaemia and increased blood pressure levels. Metabolic and renal causes were initially investigated as thyroid disease, Cushing syndrome and tubulopathies were excluded during the first week of admission. However, further questioning of the patient, revealed that she had been consuming several sachets of raw liquorice lollies (ignored amount) obtained from a herbalist a month ago. Based on the history and clinical findings, liquorice poisoning was highly suspected; an apparent mineralocorticoid excess secondary to ingestion of liquorice. Afterwards, levels of aldosterone and plasma renin activity were measured and found low 3 weeks later; therefore, our clinical suspicion was established. During the patient's stay at the hospital, liquorice was stopped and potassium supplements were started. Subsequently, a week after, the patient fully recovered without any significant sequelae.

Licorice abuse: time to send a warning message

Licorice extract has always been recognized as a sweetener and a thirst quencher. Its nutritive value is overrated by many who consume significant amounts and are prone to complications. Glycyrrhetic acid, the active metabolite in licorice, inhibits the enzyme 11-ß-hydroxysteroid dehydrogenase enzyme type 2 with a resultant cortisol-induced mineralocorticoid effect and the tendency towards the elevation of sodium and reduction of potassium levels. This aldosterone-like action is the fundamental basis for understanding its health benefits and the wide spectrum of adverse effects. Herein, we present a comprehensive review of licorice along with the reported complications related to excess intake. Despite its apparent use in a few clinical scenarios, the daily consumption of licorice is never justified because its benefits are minor compared to the adverse outcomes of chronic consumption. The review highlights the importance of investigating the dietary habits and herbal remedies which are being used worldwide on cultural and habitual bases rather than reliable scientific evidence. Licorice is a US Food and Drug Administration (FDA) approved food supplement used in many products without precise regulations to prevent toxicity. Increased awareness among the public is required through TV commercials, newspapers, internet sites, magazines and product labels regarding the upper limit of ingestion and health hazards associated with excess intake. We hope that this review will serve as a warning message that should be transmitted from physicians to patients to avoid excessive licorice intake as well as a message to the FDA to start regulating the use of this substance.

Grapefruit juice and licorice increase cortisol availability in patients with Addison's disease

OBJECTIVE

Failure to mirror the diurnal cortisol profile could contribute to the impaired subjective health status in Addison's disease (AD). Some patients report benefit from the use of various nutritional compounds. The objective of this study was to investigate the impact of licorice and grapefruit juice (GFJ) on the absorption and metabolism of cortisone acetate (CA).

DESIGN

Patients (n=17) with AD on stable CA replacement therapy were recruited from the outpatient clinic at Haukeland University Hospital, Norway. They were assessed on their ordinary CA medication and following two 3-day periods of co-administration of licorice or GFJ.

METHODS

Time series of glucocorticoids (GCs) in serum and saliva were obtained, and GCs in 24 h urine samples were determined. The main outcome measure was the area under the curve (AUC) for serum cortisol in the first 2.6 h after orally administered CA.

RESULTS

Compared with the ordinary treatment, the median AUC for serum cortisol increased with licorice (53 783 vs 50 882, P<0.05) and GFJ (60 661 vs 50 882, P<0.05). Median cortisol levels in serum were also elevated 2.6 h after tablet ingestion (licorice 223 vs 186 nmol/l, P<0.05; GFJ 337 vs 186 nmol/l, P<0.01). Licorice increased the median urinary cortisol/cortisone ratio (0.43 vs 0.21, P<0.00001), whereas GFJ increased the (allo-tetrahydrocortisol+tetrahydrocortisol)/tetrahydrocortisone ratio (0.55 vs 0.43, P<0.05).

CONCLUSION

Licorice and in particular GFJ increased cortisol available to tissues in the hours following oral CA administration. Both patients and physicians should be aware of these interactions.

Glycyrrhetinic acid attenuates vascular smooth muscle vasodilatory function in healthy humans

Abnormal glucocorticoid metabolism contributes to vascular dysfunction and cardiovascular disease. Cortisol activation of vascular mineralocorticoid and glucocorticoid receptors is regulated by two types of 11β-HSD (11-β hydroxysteroid dehydrogenase), namely 11β-HSD2 and 11β-HSD1 (type 2 and type 1 11β-HSD respectively). We hypothesized that inhibition of 11β-HSD would attenuate vascular function in healthy humans. A total of 15 healthy subjects were treated with the selective 11β-HSD inhibitor GA (glycyrrhetinic acid) or matching placebo in a randomized double-blinded cross-over trial. 11β-HSD activity was assessed by the urinary cortisol/cortisone ratio, and vascular function was measured using strain-gauge plethysmography. Endothelial function was measured through incremental brachial artery administration of methacholine (0.3–10 μg/min) and vascular smooth muscle function with incremental verapamil (10–300 μg/min). GA increased the 24-h urinary cortisol/cortisone ratio compared with placebo (P=0.008). GA tended to reduce the FBF (forearm blood flow) response to methacholine (P=0.09) and significantly reduced the FBF response to verapamil compared with placebo (P=0.04). MAP (mean arterial pressure) did not differ between the study conditions. 11β-HSD inhibition attenuated vascular smooth muscle vasodilatory function in healthy humans. Disturbances in cortisol activity resulting from 11β-HSD inactivation is therefore a second plausible mechanism for mineralocorticoid-mediated hypertension in humans.

In vitro effects of glycyrrhetinic acid on the growth of clinical isolates of Candida albicans

Compounds derived from Glycyrrhiza glabra L. root have been used widely for centuries for their numerous therapeutic properties. The present study aimed to test the in vitro activity against Candida albicans strains of the compound 18-beta glycyrrhetinic acid (18-beta GA), derived from the root of Glycyrrhiza species. This antimicrobial activity was assessed using the National Committee for Clinical Laboratory Standards (NCCLS) method on C. albicans strains that were isolated from patients with recurrent vulvovaginal candidiasis (RVVC). The in vitro growth of the C. albicans strains was markedly reduced, in a pH-dependent manner, by relatively low doses (6.2 microg/mL) of 18-beta GA. The results demonstrate that 18-beta GA is a promising biological alternative for the topical treatment of recurrent vulvovaginal candidiasis (RVVC).

Licorice extract does not impair the male reproductive function of rats

The effect of water extract of licorice (Glycyrrhiza uralensis), one of the most widely used medicinal plants in Oriental nations and in Europe, on male reproductive function was investigated in rats. Licorice extract was prepared as in Oriental clinics and orally administered at doses of 500, 1,000 or 2,000 mg/kg, the upper-limit dose (2,000 mg/kg) recommended in the Toxicity Test guideline of the Korea Food and Drug Administration, to 6-week-old male rats for 9 weeks. Licorice extract neither induced clinical signs, nor affected the daily feed consumption and body weight gain. There were no significant changes in testicular weights, gross and microscopic findings, and daily sperm production between vehicle- and licorice-treated animals, in spite of slight decreases in prostate weight and daily sperm production at the high dose (2,000 mg/kg). In addition, licorice did not affect the motility and morphology of sperm, although the serum testosterone level tended to decrease without significant difference, showing a 28.6% reduction in the high-dose (2,000 mg/kg) group. The results suggest that the no observed adverse-effect level of licorice extract is higher than 2,000 mg/kg, the upper-limit dose, and that long-term exposure to licorice might not cause profound adverse effects.

Treatment of polycystic ovary syndrome with spironolactone plus licorice

OBJECTIVE

The aim of the study was to compare the effect of spironolactone (antagonist of mineralocorticoid and androgen receptors) versus spironolactone plus licorice (agonist of mineralocorticoid receptors and mild inhibitor of androgen synthesis) on plasma renin activity, aldosterone and androgen levels in women with polycystic ovary syndrome (PCOS).

STUDY DESIGN

Thirty-two women with PCOS were divided into two groups: 16 received 100 mg spironolactone and 16 spironolactone plus 3.5 g of licorice a day. Blood pressure, body mass index, serum electrolytes, plasma renin activity, plasma aldosterone and cortisol, serum testosterone, and urinary tetrahydrocortisol/tetrahydrocortisone ratio were measured before and during treatment.

RESULTS

Mean blood pressure was significantly reduced during spironolactone treatment, while it was unchanged in women receiving spironolactone plus licorice. Twenty percent of women treated with spironolactone and none treated with the addition of licorice complained of symptoms related to volume depletion. Consistently, the activation of the renin-aldosterone system was significantly lower during spironolactone plus licorice than with spironolactone alone. The prevalence of metrorrhagia was lower in the combined therapy.

CONCLUSIONS

In patients with PCOS the mineralocorticoid properties of licorice can reduce the prevalence of side effects related to the diuretic activity of spironolactone.

Effect of licorice on PTH levels in healthy women

Licorice has been considered a medicinal plant for thousands of years. Its most common side effect is hypokalemic hypertension, which is secondary to a block of 11beta-hydroxysteroid dehydrogenase type 2 at the level of the kidney, leading to an enhanced mineralocorticoid effect of cortisol. This effect is due to glycyrrhetinic acid, which is the main constituent of the root, but other components are also present, including isoflavans, which have estrogen-like activity, and are thus involved in the modulation of bone metabolism. We investigated nine healthy women 22-26 years old, in the luteal phase of the cycle. They were given 3.5 g of a commercial preparation of licorice (containing 7.6%, w/w of glycyrrhizic acid) daily for 2 months. Plasma renin activity (PRA), aldosterone, cortisol, serum parathyroid hormone (PTH), 1,25-dihydroxy Vitamin D (1,25OHD), 25-hydroxycholecalciferol (25OHD), estradiol, FHS, LH, alkaline phosphatase (ALP), calcium, phosphate and creatinine, urinary calcium and phosphate and mineralometry were measured. PTH, 25OHD and urinary calcium increased significantly from baseline values after 2 months of therapy, while 1,25OHD and ALP did not change during treatment. All these parameters returned to pretreatment levels 1 month after discontinuation of licorice. PRA and aldosterone were depressed during therapy, while blood pressure and plasma cortisol remained unchanged.

CONCLUSIONS

licorice can increase serum PTH and urinary calcium levels from baseline value in healthy women after only 2 months of treatment. The effect of licorice on calcium metabolism is probably influenced by several components of the root, which show aldosterone-like, estrogen-like and antiandrogen activity.

Licorice reduces serum testosterone in healthy women

Licorice has been considered a medicinal plant for thousands of years. The most common side effect is hypokalemic hypertension, which is secondary to a block of 11beta-hydroxysteroid dehydrogenase type 2 at the level of the kidney, leading to an enhanced mineralocorticoid effect of cortisol. We have investigated the effect of licorice on androgen metabolism in nine healthy women 22-26 years old, in the luteal phase of the cycle. They were given 3.5 g of a commercial preparation of licorice (containing 7.6% W.W. of glycyrrhizic acid) daily for two cycles. They were not on any other treatment. Plasma renin activity, serum adrenal and gonadal androgens, aldosterone, and cortisol were measured by radioimmunoassay. Total serum testosterone decreased from 27.8+/-8.2 to 19.0+/-9.4 in the first month and to 17.5+/-6.4 ng/dL in the second month of therapy (p<0.05). It returned to pre-treatment levels after discontinuation. Androstenedione, 17OH-progesterone, and LH levels did not change significantly during treatment. Plasma renin activity and aldosterone were depressed during therapy, while blood pressure and cortisol remained unchanged.

CONCLUSIONS

Licorice can reduce serum testosterone probably due to the block of 17-hydroxysteroid dehydrogenase and 17-20 lyase. Licorice could be considered an adjuvant therapy of hirsutism and polycystic ovary syndrome.

Effect of licorice on the reduction of body fat mass in healthy subjects

The history of licorice, as a medicinal plant, is very old and has been used in many societies throughout the millennia. The active principle, glycyrrhetinic acid, is responsible for sodium retention and hypertension, which is the most common side-effect. We show an effect of licorice in reducing body fat mass. We studied 15 normal-weight subjects (7 males, age 22-26 yr, and 8 females, age 21-26 yr), who consumed for 2 months 3.5 g a day of a commercial preparation of licorice. Body fat mass (BFM, expressed as percentage of total body weight, by skinfold thickness and by bioelectrical impedance analysis, BIA) and extracellular water (ECW, percentage of total body water, by BIA) were measured. Body mass index (BMI) did not change. ECW increased (males: 41.8+/-2.0 before vs 47.0+/-2.3 after, p<0.001; females: 48.2+/-1.4 before vs 49.4+/-2.1 after, p<0.05). BFM was reduced by licorice: (male: before 12.0+/-2.1 vs after 10.8+/-2.9%, p<0.02; female: before 24.9+/-5.1 vs after 22.1+/-5.4, p<0.02); plasma renin activity (PRA) and aldosterone were suppressed. Licorice was able to reduce body fat mass and to suppress aldosterone, without any change in BMI. Since the subjects were consuming the same amount of calories during the study, we suggest that licorice can reduce fat by inhibiting 11beta-hydroxysteroid dehydrogenase Type 1 at the level of fat cells.

Pseudohyperaldosteronism: pathogenetic mechanisms

Pseudohyperaldosteronism is characterized by a clinical picture of hyperaldosteronism with suppression of plasma renin activity and aldosterone. Pseudohyperaldosteronism can be due to a direct mineralocorticoid effect, as with desoxycorticosterone, fluorohydrocortisone, fluoroprednisolone, estrogens, and the ingestion of high amounts of glycyrrhetinic acid. A block of 11-hydroxysteroid-dehydrogenase type 2 (11HSD2), the enzyme that converts cortisol into cortisone, at the level of epithelial target tissues of aldosterone, is involved in other cases. This mechanism is related either to a mutation of the gene, which encodes 11HSD2 (apparent mineralocorticoid excess syndrome and some cases of low renin hypertension) or to an acquired reduction of the activity of the enzyme due to glycyrrhetinic acid, carbenoxolone, and grapefruit juice. In other cases saturation of 11HSD2 may be involved as in severe Cushing's syndrome and chronic therapy with some corticosteroids. Recently, an activating mutation of the mineralocorticoid receptor gene has been described. Another genetic cause of pseudohyperaldosteronism is the syndrome of Liddle, which is due to a mutation of the gene encoding for beta and gamma subunits of the sodium channels.

Complementary/alternative therapies for reducing hot flashes in prostate cancer patients: reevaluating the existing indirect data from studies of breast cancer and postmenopausal women

Vasomotor hot flashes are a common problem in women who are postmenopausal or receiving antiestrogen treatment for breast cancer. Hot flashes are also a common problem after orchiectomy/luteinizing hormone-releasing hormone therapy, occurring generally in 50% to 66% of these men. Prescribed treatments for hot flashes for men on hormonal ablation treatment for prostate cancer are well documented. These conventional agents have shown good results, but their long-term efficacy, safety, and cost are still questioned. Therefore, the search for other viable agents, including nontraditional treatments, continues. Complementary/alternative treatments to alleviate hot flashes in women have generated an enormous amount of interest. However, these options have received little attention in men with hot flashes. Research with vitamin E, soy, black cohosh, red clover, and numerous other alternative treatments in women may provide some indirect but valuable insight on their potential effectiveness in men. Many of these alternatives have been a disappointment in recent randomized trials of women, and it is likely that there will be similar results with men. However, numerous supplements have yet to be tested in a clinical trial against a placebo, and clinicians should become aware of this ever-increasing list. Patients should be made aware of the primary importance of lifestyle interventions that could partially affect hot flashes and immediately affect overall health, especially during the period of androgen suppression, when it is not uncommon to observe accelerated weight changes and insulin insensitivity. Otherwise, recent research with older and newer conventional agents, such as antidepressants or estrogen/progesterone, should be emphasized at this time for moderate-to-severe hot flashes that profoundly affect daily activities and/or sleep. Antidepressant supplements (St. John's wort) or acupuncture could also be an attractive option in future investigations. Low-dose estrogen seems particularly attractive, because it is inexpensive and may simultaneously reduce hot flashes and the risk of osteoporosis in men receiving long-term androgen suppression therapy; however, the potential for cardiovascular complications must be further investigated. Ultimately, adequate research (vs placebo) should determine the fate of the alternative supplements proposed for hot flash reduction.

Lifestyle/dietary supplement partial androgen suppression and/or estrogen manipulation. A novel PSA reducer and preventive/treatment option for prostate cancer?

There is a large interest in prostate cancer prevention and/or slowing the progression of this disease via dietary/lifestyle/supplement interventions. Numerous mechanisms have been suggested as to how these interventions may lower PSA levels. However, it is possible that the primary mechanism of action is partial androgen suppression and/or estrogen manipulation.

A population physiologically based pharmacokinetic/pharmacodynamic model for the inhibition of 11-beta-hydroxysteroid dehydrogenase activity by glycyrrhetic acid

Glycyrrhizic acid is widely applied as a sweetener in food products and chewing tobacco. Habitual consumption of this compound may lead to hypertension and electrolyte disturbances due to inhibition of 11-beta-hydroxysteroid dehydrogenase by the metabolite glycyrrhetic acid. The effect of 130 mg glycyrrhetic acid/day for 5 days on 11-beta-hydroxysteroid dehydrogenase activity was studied by measuring the cortisol-cortisone ratio in 24-h urine. A twofold increase in this ratio was observed. It took 4 days for the elevated urinary cortisol-cortisone ratio to return to the baseline ratio after cessation of the treatment. The pharmacokinetics of glycyrrhetic acid were studied after the first and last dose. Using data from a previously performed single-dose study and present multiple-dose treatment, a physiologically based pharmacokinetic model for glycyrrhetic acid was developed. The variability of the pharmacokinetics of glycyrrhetic acid in the population studied could be explained for a considerable part by interindividual differences in gastrointestinal transit of glycyrrhetic acid metabolites. The relationship between glycyrrhetic acid exposure and changes in urinary cortisol-cortisone ratio was described by a pharmacodynamic model, using nonlinear mixed-effect modeling. Literature data on the inhibitory effect of glycyrrhetic acid on 11-beta-hydroxysteroid dehydrogenase activity under various exposure scenarios could be adequately described by the model. Due to the relationship between the pharmacokinetics of glycyrrhetic acid and its inhibitory effect on 11-beta-hydroxysteroid dehydrogenase activity, reflected by a change in the urinary cortisol-cortisone ratio, this ratio might serve as a noninvasive marker to identify individuals at risk for glycyrrhizic acid over-consumption.