The action of p-synephrine on hepatic carbohydrate metabolism and respiration occurs via both Ca(2+)-mobilization and cAMP production

Effects of resveratrol on rheumatic symptoms and hepatic metabolism of arthritic rats

OBJECTIVES

Resveratrol has been studied as a potential agent for treating rheumatic conditions; however, this compound suppresses glucose synthesis and glycogen catabolism when infused in perfused livers of both arthritic and healthy rats. This study investigated the effects of oral administration of resveratrol on inflammation and liver metabolism in rats with arthritis induced by Freund's adjuvant, which serves as rheumatoid arthritis model.

METHODS

Holtzman rats, both healthy and exhibiting arthritic symptoms, were orally treated with resveratrol at doses varying from 25 to 500 mg/kg for a 5-day period preceding arthritis induction, followed by an additional 20-day period thereafter. Paw edema, arthritic score and hepatic myeloperoxidase activity were assessed to evaluate inflammation. Glycogen catabolism and gluconeogenesis from lactate were respectively evaluated in perfused livers from fed and fasted rats.

RESULTS

Resveratrol decreased the liver myeloperoxidase activity at doses above 100 mg/kg, and decreased the paw edema and delayed the arthritic score at doses above 250 mg/kg. The hepatic gluconeogenesis was decreased in arthritic rats and resveratrol did not improve it. However, resveratrol did not negatively modify the gluconeogenesis in livers of healthy and arthritic rats. Glycogen catabolism was in part and slightly modified by resveratrol in the liver of arthritic and healthy rats.

CONCLUSIONS

It is improbable that resveratrol negatively affects the liver metabolism, especially considering that gluconeogenesis is highly fragile to changes in cellular architecture. The findings suggest that resveratrol could serve as alternative for treating rheumatoid arthritis. Nevertheless, prudence is advised regarding its transient effects on liver metabolism.

Ultra-high-performance liquid chromatography-quadrupole-time of flight-mass spectrometry combined with network pharmacology for analysis of potential quality markers of three processed products of Qingpi

Qingpi, a well-known traditional Chinese medicine for qi-regulating and commonly processed into three types of pieces, has been widely used in the clinical application of liver disease for thousands of years. In this study, an ultra-high-performance liquid chromatography-quadrupole-time of flight-mass spectrometry approach along with multivariate statistical analysis was developed to assess and characterize the differentiations of three processed products and confirm the potential quality markers of Qingpi. In addition, a systematic analysis combined with network pharmacology and molecular docking was performed to clarify the potential mechanism of Qingpi for the treatment of liver disease. As a result, 18 components were identified and an integrated network of Qingpi-Components-Target-Pathway-Liver Disease was constructed. Eight compounds were finally screened out as the potential quality markers acting on ten main targets and pathways of liver disease. Molecular docking analysis results indicated that the quality markers had a good binding activity with the targets. Overall, this work preliminarily identified the potential quality markers of three processed products of Qingpi, and predicted its targets in the prevention and treatment of liver disease, which can provide supporting information for further study of the pharmacodynamic substances and mechanisms of Qingpi.

p-Synephrine ameliorates alloxan-induced diabetes mellitus through inhibiting oxidative stress and inflammation via suppressing the NF-kappa B and MAPK pathways

Oxidative stress and inflammation play important roles in the development of diabetes mellitus. p-Synephrine, the primary pharmacologically active protoalkaloid in Citrus species, has been popularly consumed as a dietary supplement for weight loss management. However, the effects of p-synephrine on diabetes mellitus and the action mechanisms have not been clearly elucidated. In this study, the in vitro antioxidant effects of p-synephrine were evaluated. The data showed that p-synephrine treatment exhibited significant scavenging effects against DPPH, ABTS and OH radicals and showed high reducing power. Diabetic mice were developed by alloxan injection, followed by p-synephrine administration to investigate its hypoglycemic effects in vivo. The results showed that p-synephrine intervention significantly prevented alloxan-induced alteration in body weight, organ indexes, serum uric acid content and serum creatinine content. Meanwhile, p-synephrine application significantly improved the lipid profiles, superoxide dismutase (SOD) and catalase (CAT) activities and glutathione (GSH) contents in the serum and kidneys of diabetic mice and reduced the malondialdehyde (MDA) content in the serum of diabetic mice. Further assays suggested that p-synephrine treatment improved alloxan-induced decreases of glucose tolerance and insulin sensitivity. Also, p-synephrine supplementation altered histopathological changes in the kidneys and interscapular brown adipose tissues in diabetic mice. In addition, p-synephrine administration inhibited renal inflammation through suppressing tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) gene expression levels, as well as CD45 expression levels. The anti-inflammatory effects were probably involved in the regulation of nuclear factor-κB (NF-κB) activation and mitogen-activated protein kinase (MAPK) phosphorylation. In conclusion, p-synephrine application significantly ameliorated alloxan-induced diabetes mellitus by inhibiting oxidative stress via suppressing the NF-κB and MAPK pathways.

Resveratrol biotransformation and actions on the liver metabolism of healthy and arthritic rats

AIMS

To investigate the effects of resveratrol on glycogen catabolism and gluconeogenesis in perfused livers of healthy and arthritic rats. The actions of resveratrol-3-O-glucuronide (R3G) and the biotransformation of resveratrol into R3G was further evaluated in the livers.

MAIN METHODS

arthritis was induced with Freund's adjuvant. Resveratrol at concentrations of 10, 25, 50, 100 and 200 μM and 200 μM R3G were introduced in perfused livers. Resveratrol and metabolites were measured in the outflowing perfusate. Respiration of isolated mitochondria and activity of gluconeogenic enzymes were also evaluated in the livers.

KEY FINDINGS

resveratrol inhibited glycogen catabolism when infused at concentrations above 50 μM and gluconeogenesis even at 10 μM in both healthy and arthritic rat livers, but more sensitive in these latter. Resveratrol above 100 μM inhibited ADP-stimulated respiration and the activities of NADH- and succinate-oxidases in mitochondria, which were partially responsible for gluconeogenesis inhibition. Pyruvate carboxylase activity was inhibited by 25 μM resveratrol and should inhibit gluconeogenesis already at low concentrations. Resveratrol was significantly metabolized to R3G in healthy rat livers, however, R3G formation was lower in arthritic rat livers. The latter must be in part a consequence of a lower glucose disposal for glucuronidation. When compared to resveratrol, R3G inhibited gluconeogenesis in a lower extension and glycogen catabolism in a higher extension.

SIGNIFICANCE

the effects of resveratrol and R3G tended to be transitory and existed only when the resveratrol is present in the organ, however, they should be considered because significant serum concentrations of both are found after oral ingestion of resveratrol.

p-Synephrine and its various pharmacological effects

There is a number of diseases for which, scientists are constantly looking for a promising new treatments. Isolation of novel substances with biological activity from plants gives hope for its use in treatment. In this review, we focused on the biological activity of p-synephrine (4-(2-aminoethyl)phenol) which was previously confirmed during both in vitro and in vivo tests. The main part of the review is dedicated to the anti-obesity activity of p-synephrine, as obesity is a disease of contemporary civilization. However, synephrine also possesses anti-diabetic, anti-inflammatory and antidepressant activity and it is confirmed to be a hypotensive agent in portal hypertension. The review also emphasize that, based on current knowledge, the use of p-synephrine appears to be exceedingly safe with only limited range of side effects. Therefore, it seems that this substance may be of great importance in the pharmacotherapy of many disease states and further research is necessary.

p-Synephrine, ephedrine, p-octopamine and m-synephrine: Comparative mechanistic, physiological and pharmacological properties

Confusion and misunderstanding exist regarding the lack of cardiovascular and other adverse health effects of p-synephrine and p-octopamine relative to ephedrine and m-synephrine (phenylephrine) which are known for their effects on the cardiovascular system. These four molecules have some structural similarities. However, the structural and stereochemical differences of p-synephrine and p-octopamine as related to ephedrine and m-synephrine result in markedly different adrenergic receptor binding characteristics as well as other mechanistic differences which are reviewed. p-Synephrine and p-octopamine exhibit little binding to α-1, α-2, β-1 and β-2 adrenergic receptors, nor are they known to exhibit indirect actions leading to an increase in available levels of endogenous norepinephrine and epinephrine at commonly used doses. The relative absence of these mechanistic actions provides an explanation for their lack of production of cardiovascular effects at commonly used oral doses as compared to ephedrine and m-synephrine. As a consequence, the effects of ephedrine and m-synephrine cannot be directly extrapolated to p-synephrine and p-octopamine which exhibit significantly different pharmacokinetic, and physiological/pharmacological properties. These conclusions are supported by human, animal and in vitro studies that are discussed.

p-Synephrine exhibits anti-adipogenic activity by activating the Akt/GSK3β signaling pathway in 3T3-L1 adipocytes

This work aimed to investigate the effects of p-synephrine on the differentiation of adipocyte and explore the underlying mechanism. We found that p-synephrine suppressed the 3T3-L1 cell adipogenesis by reducing the expression level of CCAAT/enhancer-binding protein α (C/EBPα) and peroxisome proliferator-activated receptor γ (PPARγ), which subsequently led to a reduction in the fatty acid-binding protein 4 (aP2) expression. p-Synephrine treatment markedly activated the protein kinase B (PKB/Akt) pathway and sequentially inhibited glycogen synthase kinase 3β (GSK3β) activity. Inhibition of GSK3β activity by LiCl was found to partially ameliorate the above-mentioned effects. All these data suggested that p-synephrine exhibited the anti-adipogenic effects via the regulation of Akt signaling pathway and the suppression of adipogenesis-related proteins. PRACTICAL APPLICATIONS: Citrus aurantium often uses as herbal or dietary supplement in various countries around the world, including in Seville, Spain and South Africa. In traditional Chinese herbs, it is referred to as "Fructus aurantii immaturus," "Zhi shi," or "Zhi ke," and has been used for hundreds of years for various digestive problems. Its primary protoalkaloid, p-synephrine, exhibited lipolytic effects and energy expenditure, which has rapidly replaced ephedrine as an "ephedra-free" alternative dietary supplement. The current study firstly demonstrated the anti-adipogenic effects of p-synephrine in 3T3-L1 preadipocytes, which was due to the regulation of Akt signaling pathway and the subsequent suppression of adipogenesis-related proteins. The present study may offer invaluable opinions into the mechanisms of body weight/fat-losing activities of p-synephrine in theory, and scientific experimental evidence on dietary supplement in practice. p-Synephrine could be utilized for the preventive and therapeutic uses against metabolic syndrome.

Nutritional and non-nutritional agents that stimulate white adipose tissue browning

Obesity is a public health problem present in both developed and developing countries. The white adipose tissue (WAT) is the main deposit of lipids when there is an excess of energy. Its pathological growth is directly linked to the development of obesity and to a wide number of comorbidities, such as insulin-resistance, cardiovascular disease, among others. In this scenario, it becomes imperative to develop new approaches to the treatment and prevention of obesity and its comorbidities. It has been documented that the browning of WAT could be a suitable strategy to tackle the obesity epidemic that is developing worldwide. Currently there is an intense search for bioactive compounds with anti-obesity properties, which present the particular ability to generate thermogenesis in the brown adipose tissue (BAT) or beige. The present study provide recent information of the bioactive nutritional compounds capable of inducing thermogenesis and therefore capable of generate positive effects on health.

Actions of p-synephrine on hepatic enzyme activities linked to carbohydrate metabolism and ATP levels in vivo and in the perfused rat liver

p-Synephrine is one of the main active components of the fruit of Citrus aurantium (bitter orange). Extracts of the bitter orange and other preparations containing p-synephrine have been used worldwide to promote weight loss and for sports performance. The purpose of the study was to measure the action of p-synephrine on hepatic enzyme activities linked to carbohydrate and energy metabolism and the levels of adenine mononucleotides. Enzymes and adenine mononucleotides were measured in the isolated perfused rat liver and in vivo after oral administration of the drug (50 and 300 mg/kg) by using standard techniques. p-Synephrine increased the activity of glycogen phosphorylase in vivo and in the perfused liver. It decreased, however, the activities of pyruvate kinase and pyruvate dehydrogenase also in vivo and in the perfused liver. p-Synephrine increased the hepatic pools of adenosine diphosphate and adenosine triphosphate. Stimulation of glycogen phosphorylase is consistent with the reported increased glycogenolysis in the perfused liver and increased glycemia in rats. The decrease in the pyruvate dehydrogenase activity indicates that p-synephrine is potentially capable of inhibiting the transformation of carbohydrates into lipids. The capability of increasing the adenosine triphosphate-adenosine diphosphate pool indicates a beneficial effect of p-synephrine on the cellular energetics.

Safety evaluation of p-synephrine following 15 days of oral administration to healthy subjects: A clinical study

Extracts of bitter orange (BOE, Citrus aurantium L.) and its primary protoalkaloid p-synephrine are extensively consumed as dietary supplements. p-Synephrine is also present in foods and juices prepared from various Citrus species. The safety of p-synephrine has been questioned as a result of structural similarities with ephedrine. This study assessed the cardiovascular (stimulant) and hemodynamic effects of BOE (49 mg p-synephrine) daily given to 16 healthy subjects for 15 days in a placebo-controlled, cross-over, double-blinded study. A physical evaluation by a cardiologist, as well as heart rates, blood pressures, and electrocardiograms were determined, and blood samples were drawn at baseline, and Days 5, 10, and 15. Serum levels for caffeine and p-synephrine were measured at 1 and 2 weeks. Subjects completed a 10-item health and metabolic questionnaire at baseline and on Day 15. No significant changes occurred in heart rate, electrocardiograms, systolic blood or diastolic pressures, blood cell counts, or blood chemistries in either the control or p-synephrine treated groups at any time point. No adverse effects were reported in response to the bitter orange (p-synephrine). Caffeine consumed by the participants varied markedly. Under these experimental conditions, BOE and p-synephrine were without stimulant (cardiovascular) and adverse effects.

Safety, Efficacy, and Mechanistic Studies Regarding Citrus aurantium (Bitter Orange) Extract and p-Synephrine

Citrus aurantium L. (bitter orange) extracts that contain p-synephrine as the primary protoalkaloid are widely used for weight loss/weight management, sports performance, appetite control, energy, and mental focus and cognition. Questions have been raised about the safety of p-synephrine because it has some structural similarity to ephedrine. This review focuses on current human, animal, in vitro, and mechanistic studies that address the safety, efficacy, and mechanisms of action of bitter orange extracts and p-synephrine. Numerous studies have been conducted with respect to p-synephrine and bitter orange extract because ephedra and ephedrine were banned from use in dietary supplements in 2004. Approximately 30 human studies indicate that p-synephrine and bitter orange extracts do not result in cardiovascular effects and do not act as stimulants at commonly used doses. Mechanistic studies suggest that p-synephrine exerts its effects through multiple actions, which are discussed. Because p-synephrine exhibits greater adrenergic receptor binding in rodents than humans, data from animals cannot be directly extrapolated to humans. This review, as well as several other assessments published in recent years, has concluded that bitter orange extract and p-synephrine are safe for use in dietary supplements and foods at the commonly used doses. Copyright © 2017 The Authors Phytotherapy Research Published by John Wiley & Sons Ltd.

Liver toxicity mechanisms of herbs commonly used in Latin America

Mexico owns approximately 4500 medicinal plants species, a great diversity that position it at the second place after China. According to the Mexican health department, 90% of common population consumes them to treat various diseases. Additionally, herbal remedies in Latin America (LA) are considered a common practice, but the frequency of use and the liver damage related to its consumption is still unknown. Despite the high prevalence and indiscriminate herbal consumption, the exact mechanism of hepatotoxicity and adverse effects is not fully clarified and is still questioned. Some herb products associated with herb induced liver injury (HILI) are characterized by presenting a different chemical composition that may vary from batch to batch, also the biological activity of many medicinal plants and other natural products are directly related to their most active component and its concentration. There are two main biological components that are associated with liver damage, alkaloids, and flavonoids, which are frequent constituents of commonly used herbs. The interaction with the different cytochrome P-450 isoforms, inflammatory, and oxidative activities seem to be the main damage pathway involved in the liver. It is important to know the herbal adverse effects and mechanisms involved; therefore, this article is focused on the beneficial and deleterious effects as well as the possible toxicity mechanisms and interactions of the herbs that are frequently used in LA, since the herb-host interaction may not always be the expected or desired depending on the clinical context in which it is administered.

Factors involved in white-to-brown adipose tissue conversion and in thermogenesis: a review

Obesity is the result of energy intake chronically exceeding energy expenditure. Classical treatments against obesity do not provide a satisfactory long-term outcome for the majority of patients. After the demonstration of functional brown adipose tissue in human adults, great effort is being devoted to develop therapies based on the adipose tissue itself, through the conversion of fat-accumulating white adipose tissue into energy-dissipating brown adipose tissue. Anti-obesity treatments that exploit endogenous, pharmacological and nutritional factors to drive such conversion are especially in demand. In the present review, we summarize the current knowledge about the various molecules that can be applied in promoting white-to-brown adipose tissue conversion and energy expenditure and the cellular mechanisms involved.

A Review of Natural Stimulant and Non-stimulant Thermogenic Agents

Obesity and overweight are major health issues. Exercise and calorie intake control are recognized as the primary mechanisms for addressing excess body weight. Naturally occurring thermogenic plant constituents offer adjunct means for assisting in weight management. The controlling mechanisms for thermogenesis offer many intervention points. Thermogenic agents can act through stimulation of the central nervous system with associated adverse cardiovascular effects and through metabolic mechanisms that are non-stimulatory or a combination thereof. Examples of stimulatory thermogenic agents that will be discussed include ephedrine and caffeine. Examples of non-stimulatory thermogenic agents include p-synephrine (bitter orange extract), capsaicin, forskolin (Coleus root extract), and chlorogenic acid (green coffee bean extract). Green tea is an example of a thermogenic with the potential to produce mild but clinically insignificant undesirable stimulatory effects. The use of the aforementioned thermogenic agents in combination with other extracts such as those derived from Salacia reticulata, Sesamum indicum, Lagerstroemia speciosa, Cissus quadrangularis, and Moringa olifera, as well as the use of the carotenoids as lutein and fucoxanthin, and flavonoids as naringin and hesperidin can further facilitate energy metabolism and weight management as well as sports performance without adverse side effects. © 2016 The Authors Phytotherapy Research published by John Wiley & Sons Ltd.

Fast hepatic biotransformation of p-synephrine and p-octopamine and implications for their oral intake

Orally ingested p-synephrine, due to its fast transformation, may be acting primarily in the periportal region of the liver and only marginally in other tissues.