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, ß-1 and ß-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.

Review of Published Bitter Orange Extract and p-Synephrine Adverse Event Clinical Study Case Reports.

p-Synephrine is the primary active ingredient in bitter orange (Citrus aurantium) extract and is present in other citrus species. This review summarizes all known case reports that have been published regarding adverse events associated with multi-ingredient dietary supplements containing bitter orange extract. A common characteristic of all the case studies was the assumption that if bitter orange extract is listed on the label of the product it is the most likely cause of any adverse effect, although in no case was the presence of p-synephrine determined or a direct link demonstrated. No case study reviewed the existing published literature, and all failed to note that numerous clinical studies have not demonstrated adverse effects at commonly used doses. Most studies did not indicate the composition of the product involved, and no study analyzed the product in question. In no case was a direct correlation between the event and p-synephrine made. Although p-synephrine and ephedrine have some structural similarity, the structural differences result in markedly different pharmacokinetic, physiological, and pharmacological effects, and thus the effects produced by ephedrine cannot be extrapolated to p-synephrine.

The fallacy of enzymatic hydrolysis for the determination of bioactive curcumin in plasma samples as an indication of bioavailability: a comparative study.

BACKGROUND: Numerous health benefits have been demonstrated for curcumin which is extracted from turmeric (Curcuma longa L). However, due to its poor absorption in the free form in the gastrointestinal tract and rapid biotransformation, various formulations have been developed to enhance its bioavailability. Previous studies indicate that the free form of curcumin is more bioactive than its conjugated counterparts in target tissues. Most curcumin pharmacokinetics studies in humans designed to assess its absorption and bioavailability have measured and reported total (free plus conjugated) curcumin, but not free, bioactive curcumin in the plasma because enzymatic hydrolysis was employed prior to its extraction and analysis. Therefore, the bioavailability of free curcumin cannot be determined. METHODS: Eight human subjects (4 male, 4 female) consumed a single dose of 400 mg curcumin in an enhanced absorption formulation, and blood samples were collected over 6 h. Plasma was treated either with or without glucuronidase/sulfatase prior to extraction. Curcumin and its major metabolites were analyzed using HPLC-tandem mass spectrometry. In addition, the literature was searched for pharmacokinetic studies involving curcumin using PubMed and Google Scholar, and the reported bioavailability data were compared based on whether hydrolysis of plasma samples was used prior to sample analysis. RESULTS: Hydrolysis of blood plasma samples prior to extraction and reporting the results as "curcumin" obscures the amount of free, bioactive curcumin and total curcuminoids as compared to non-hydrolyzed samples. As a consequence, the data and biological effects reported by most pharmacokinetic studies are not a clear indication of enhanced plasma levels of free bioactive curcumin due to product formulations, leading to a misrepresentation of the results of the studies and the products when enzymatic hydrolysis is employed. CONCLUSIONS: When enzymatic hydrolysis is employed as is the case with most studies involving curcumin products, the amount of free bioactive curcumin is unknown and cannot be determined. Therefore, extreme caution is warranted in interpreting published analytical results from biological samples involving ingestion of curcumin-containing products. TRIAL REGISTRATION: ClinicalTrails.gov, trial identifying number NCT04103788 , September 24, 2019. Retrospectively registered.

Curcumin, Hesperidin, and Rutin Selectively Interfere with Apoptosis Signaling and Attenuate Streptozotocin-Induced Oxidative Stress-Mediated Hyperglycemia.

Type I Diabetes is characterized by the presence of hyperglycemia due to insulin deficiency and consequent impaired hepatic glucose metabolism. During diabetes, the liver becomes the most important tissue for the regulation of serum glucose. However, elevated glucose causes continuous oxidative damage to the liver, reducing its capacity to ameliorate hyperglycemia, which contributes to macrovascular complications [1]. Numerous epidemiological studies have demonstrated that excess human consumption of diets rich in specific bioflavonoid phytochemicals attenuates the effects of diabetes. Thus, this study was designed to investigate whether a bioflavonoid mixture could : i) attenuate streptozotocin (STZ)-induced hyperglycemia, ii) potentiate antioxidant signaling in the liver, and iii) ameliorate the apoptotic signaling cascade in the liver of STZ-induced hyperglycemic mice. In order to examine our hypothesis, three well-investigated antioxidant phytochemicals, curcumin, hesperidin and rutin, were combined into a mixture (CHR) for this study. Diabetes was induced in 6-month-old female ICR mice by STZ (100 mg/kg, i.p.) administration, and CHR or vehicle control was orally administered (200 mg/kg per body weight of each ingredient) to the hyperglycemic mice (blood glucose levels > 250 mg/dl) for a period of 14 days. Administration of CHR to the hyperglycemic mice significantly reduced blood glucose levels, attenuated STZ-induced lipid peroxidation and total nitrate/nitrite levels, and significantly augmented the expression of superoxide dismutase and glutathione in the liver. STZ-induced hyperglycemia resulted in downregulation of antiapoptotic proteins Bcl-2 by 66% and Bcl-XL by 51%, and upregulation of the pro-apoptotic Bad (69%) with an increase in the ratio of cytosolic/mitochondrial cytochrome c by 81% in hepatic tissue. Administration of CHR significantly ameliorated apoptotic signaling in STZ-induced diabetic mice, significantly increasing Bad/Bcl-2 and Bad/Bcl-XL ratios to 410% and 244% respectively in the hyperglycemic group. This study demonstrated that a bioflavonoid mixture of curcumin, hesperidin and rutin (CHR) ameliorates hepatic oxidative stress caused by STZ-induced hyperglycemia, resulting in improved hepatic function and glucose regulation.

A review and evaluation of the efficacy and safety of Cissus quadrangularis extracts.

Extracts and powders of Cissus quadrangularis have been used for many years to promote bone and tissues healing, as an analgesic, to treat infections, as an anabolic, and to promote weight loss and weight management. This review summarizes the studies in animals, humans and in vitro systems that have been conducted to determine the efficacy and safety of various Cissus preparations. Animal and in vitro studies provide support for the use of Cissus in promoting bone fracture healing and as an anti-osteoporotic. Several human studies support the use of Cissus extracts in weight management. No studies have been conducted demonstrating that Cissus exhibits anabolic and body building activities. Based on studies to date, Cissus extracts appear to be exceedingly safe and free of adverse effects at the doses commonly used. A wide variety of chemical constituents have been isolated and identified from Cissus extracts, including steroids, flavonoids, stilbenes, iridoids, triterpenes and gallic acid derivatives. However, in few cases have specific physiological effects been related to identifiable constituents. Better standardization of extracts and more well-controlled human studies are required.

A novel dietary supplement containing multiple phytochemicals and vitamins elevates hepatorenal and cardiac antioxidant enzymes in the absence of significant serum chemistry and genomic changes.

A novel dietary supplement composed of three well-known phytochemicals, namely, Salvia officinalis (sage) extract, Camellia sinensis (oolong tea) extract, and Paullinia cupana (guarana) extract, and two prominent vitamins (thiamine and niacin) was designed to provide nutritional support by enhancing metabolism and maintaining healthy weight and energy. The present study evaluated the safety of this dietary supplement (STG; S=sage; T=tea; G=guarana) and assessed changes in target organ antioxidant enzymes (liver, kidneys and heart), serum chemistry profiles and organ histopathology in Fisher 344 rats. Adult male and female Fisher 344 rats were fed control (no STG) or STG containing (1X and 7X, 1X=daily human dose) diets and sacrificed after 2 and 4 months. Serum chemistry analysis and histopathological examination of three vital target organs disclosed no adverse influence on protein, lipid and carbohydrate profiles, genomic integrity of the liver and/or the tissue architecture. However, analysis of the most important antioxidant components in the liver, kidney and heart homogenates revealed a dramatic increase in total glutathione concentrations, glutathione peroxidase and superoxide dismutase enzyme activities. Concomitantly, oxidative stress levels (malondialdehyde accumulation) in these three organs were less than control. Organ specific serum markers (ALT/AST for the liver; CPK/AST for the heart; BUN/creatinine for kidneys) and the genomic integrity disclosed no STG-induced alteration. Some of the serum components (lipid and protein) showed insignificant changes. Overall, STG-exposed rats were more active, and the results suggest that STG exposure produces normal serum chemistry coupled with elevated antioxidant capacity in rats fed up to seven times the normal human dose and does not adversely influence any of the vital target organs. Additionally, this study reiterates the potential benefits of exposure to a pharmacologically relevant combination of phytochemicals compared to a single phytochemical entity.

Long term exposure effect of a unique metabolic nutrition system containing a diverse group of phytochemicals on serum chemistry and genomic and non-genomic changes in the liver of female B6C3F1 mice.

The nutritional value and therapeutic benefits coupled with presumed safety have heightened interest in the use of custom designed dietary supplements. Their use has increased substantially since the passage of the 1994 Dietary Supplement Health Education Act. However, few well-controlled studies have been conducted to assess the safety and potential adverse effects of dietary supplements. MNSO (MNS Orange-AdvoCare) is a unique combination of vitamins, minerals, omega-3 fatty acids and herbal extracts designed to provide a strong foundation of nutritional support, enhance thermogenesis, heighten energy levels and improve immune status. This investigation was designed to explore the safety and toxic effects, if any, of 12 months of continuous exposure to the ephedra and caffeine containing MNSO on serum chemistry and histopathology of seven vital target organs in female B6C3F1 mice. MNSO is enriched with extracts of citrus, Ephedra, Ginkgo, green tea and Ocimum. In this study, mice were fed control (-MNSO) or MNSO (1x-10x, 1x = daily human dose) diets. Blood was collected from all groups including the control every 4 months for serum chemistry analysis (enzyme, lipid, carbohydrate, electrolyte profiles), and liver tissue was collected for tissue biochemistry and histopathology. Multiple biochemical parameters included: (i) determination of oxidative stress via lipid peroxidation and (ii) assessment of genomic integrity via DNA fragmentation. In addition, food consumption and body weight changes were also monitored biweekly. The data showed that 12 months ingestion of 10x-MNSO did not significantly influence organ histopathology, alter the normal serum chemistry profile or any of the crucial tissue biochemistry. MNSO-exposed animals were more active, consumed more food and were relatively leaner compared with the controls. This study indicates that a caffeine and ephedra containing metabolic nutrition system is non-toxic and non-hepatotoxic in mice at up to 10x the human consumption dose of ephedra.

Pre-exposure to a novel nutritional mixture containing a series of phytochemicals prevents acetaminophen-induced programmed and unprogrammed cell deaths by enhancing BCL-XL expression and minimizing oxidative stress in the liver.

From a disease-prevention perspective, recent progress in phytochemical and nutraceutical research clearly suggests (benefits outweigh the risk pattern). Although powerful antioxidant properties have been the most acclaimed mechanism of action for these entities, the individual antioxidants studied in clinical trials do not appear to have consistent preventative effects. The actions of the antioxidant nutrients alone do not explain the observed health benefits of diets rich in fruits and vegetables for chronic diseases. Therefore, we proposed that the additive and synergistic effects of phytochemicals in fruits and vegetables are responsible for these potent antioxidant and anticancer activities, and that the benefit of a diet rich in fruits and vegetables is attributed to the complex mixture of phytochemicals present in plants [1]. Surprisingly, however, no studies have attempted to evaluate the combined antitoxic potential of a phytochemical-nutraceutical mixture (PNM) in in vivo models. Therefore, this study, for the first time, was designed to investigate whether pre-exposure to a unique PNM has the ability to impede mechanistic events involved in acetaminophen (APAP)-induced hepatotoxicity. Besides several vitamins and minerals in balanced proportions (approximately US RDA), the PNM used in this investigation contained several well-known phytochemicals such as citrus flavonoids, red wine polyphenols, Garcinia, Gymnema, Ginkgo, Ephedra sinica, Camellia sinensis, Silybum, Guarana, Eluthero, Allium sativum and Ocimum basilicum extracts. To evaluate PNM's antitoxic potential, groups of animals ICR mice, 3 months old) received either a control diet or PNM containing diets (1X and 10X) for 4 weeks. On day-28, animals were divided into two subgroups. Half the animals were administered normal saline and the other half received 400mg/kg ip injections of APAP. All the animals were sacrificed 24h after APAP exposure. Serum and tissue (liver and kidneys) samples were analyzed. APAP alone caused massive liver injury (nearly 495-fold increase in ALT) and oxidative stress (Lipid peroxidation: 268% increase in MDA) coupled with genomic DNA fragmentation (288% increase). Exposure to 1X-PNM for 28 days significantly reduced animal mortality and all the APAP-induced biochemical events (In 1X-PNM + AP: ALT leakage decreased to 54 fold; MDA accumulation decreased to 125%, and DNA fragmentation decreased to 122%), whereas 10X-PNM + APAP slightly escalated both oxidative stress and genomic DNA fragmentation preceding liver injury. Liver homogenates subjected to western blot analysis disclosed the ability of 1X-PNM to counteract APAP-induced decrease in Bcl-xL expression. Histopathological evaluation of stained liver tissue sections indicated anti-apoptogenic and anti-necrogenic reponses coupled with near complete prevention of glycogen depletion by 1X-PNM. Collectively, our investigation suggests that a mixture containing an assortment of phytochemicals/nutraceuticals may serve as a much more powerful blend in preventing drug or chemical-induced organ injuries than a single phytochemical or nutraceutical entity. In addition, ephedra and caffeine containing PNM-exposure in a controlled manner may potentially shield vital target organs from toxicities caused by intentional, unintentional or accidental exposures to structurally and functionally diverse drug and chemical entities.

Proanthocyanidin exposure to B6C3F1 mice significantly attenuates dimethylnitrosamine-induced liver tumor induction and mortality by differentially modulating programmed and unprogrammed cell deaths.

Proanthocyanidins are of current interest as chemopreventive agents. The potential of the pre-, post- and co-exposure of proanthocyanidin-rich grape seed extract (GSPE) in preventing, reducing and/or delaying dimethylnitrosamine (N-nitrosodimethylamine, DMN)-induced liver tumorigenesis, carcinogenesis and mortality in male B6C3F1 mice was determined. Animals were divided into six groups: I-control, II-GSPE alone, III-DMN alone, IV-GSPE+DMN, V-DMN exposure (3 months) followed by GSPE diet (9 months) and VI-GSPE diet (3 months)+DMN (3 months)+control diet (6 months). DMN exposure (0-8 weeks: 5mg/kg; 8-12 weeks: 10mg/kg, i.p.) was limited to a total period of 3 months. GSPE was incorporated in laboratory chow (ADI: 100mg/kg b.w.). Animals were sacrificed at 3 month intervals, and serum chemistry, liver histopathology, integrity of hepatic genomic DNA, antioxidant status, and rates of apoptotic and necrotic cell deaths were determined. DMN-induced liver tumor formation (85%) and animal lethality (38%) were powerfully antagonized by co-administration of GSPE+DMN (tumor positive: 45%; death: 11%). More than 75% of the DMN-treated animals had numerous tumors (five or more), which were significantly reduced in the GSPE+DMN group (35%). GSPE also negatively influenced other protocols specifically designed to test initiation and progression phases. Thus, GSPE was instrumental in modulating metabolic cascades and regulated orchestration of cell death processes involved during the multistage tumorigenic process. These results unraveled that long-term exposure to proanthocyanidin-rich grape seed extract may serve as a potent barrier to all three stages of DMN-induced liver carcinogenesis and tumorigenesis by selectively altering oxidative stress, genomic integrity and cell death patterns in vivo.

Molecular mechanisms of cardioprotection by a novel grape seed proanthocyanidin extract.

Free radicals and oxidative stress play a crucial role in the pathophysiology of a broad spectrum of cardiovascular diseases including congestive heart failure, valvular heart disease, cardiomyopathy, hypertrophy, atherosclerosis and ischemic heart disease. We have demonstrated that IH636 grape seed proanthocyanidin extract (GSPE) provides superior antioxidant efficacy as compared to Vitamins C, E and beta-carotene. A series of studies were conducted using GSPE to demonstrate its cardioprotective ability in animals and humans. GSPE supplementation improved cardiac functional assessment including post-ischemic left ventricular function, reduced myocardial infarct size, reduced ventricular fibrillation (VF) and tachycardia, decreased the amount of reactive oxygen species (ROS) as detected by ESR spectroscopy and reduced malondialdehyde (MDA) formation in the heart perfusate. Cardiomyocyte apoptosis detected by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) staining. In concert, the proapoptotic signals mediated by JNK-l and c-fos proteins were also reduced suggesting that the novel cardioprotective properties of GSPE may be at least partially attributed to its ability to block anti-death signaling mediated through the proapoptotic transcription factors and genes such as JNK-1 and c-JUN. In a separate study, GSPE pretreatment significantly inhibited doxorubicin-induced cardiotoxicity as demonstrated by reduced serum creatine kinase (CK) activity, DNA damage and histopathological changes in the cardiac tissue of mice. Concentration-dependent efficacy of GSPE was also assessed in a hamster atherosclerosis model. Approximately 49 and 63% reduction in foam cells, a biomarker of early stage atherosclerosis, were observed following supplementation of 50 and 100 mg GSPE/kg body weight, respectively. A human clinical trial was conducted on hypercholesterolemic subjects. GSPE supplementation significantly reduced oxidized LDL, a biomarker of cardiovascular diseases. Finally, a cDNA microarray study demonstrated significant inhibition of inducible endothelial CD36 expression, a novel cardioregulatory gene, by GSPE. These results demonstrate that GSPE may serve as a potential therapeutic tool in promoting cardiovascular health via a number of novel mechanisms.

Mechanistic pathways of antioxidant cytoprotection by a novel IH636 grape seed proanthocyanidin extract.

To understand the bioavailability and mechanistic pathways of cytoprotection by IH636 grape seed proanthocyanidin extract (GSPE, commercially known as ActiVin) a series of in vitro and in vivo studies were conducted. Comparative protective abilities of GSPE, and vitamins C and E, singly and in combination, were assessed against smokeless tobacco extract (STE)-induced oxidative stress, DNA fragmentation and apoptotic cell death in a primary culture of normal human oral keratinocytes. GSPE protected against STE-induced oxidative stress, DNA damage and apoptotic cell death, and provided better protection as compared to vitamins C and E, singly and in combination. The bioavailability and protective ability of GSPE were examined against acetaminophen (AP)-induced hepato- and nephrotoxicity, amiodarone (AM)-induced lung toxicity, doxorubicin (DX)-induced cardiotoxicity and dimethylnitrosamine (DM)-induced spleenotoxicity in mice. GSPE-fed animals were compared with GSPE-untreated mice to evaluate the protective ability of GSPE against these structurally diverse drugs/chemicals. Serum chemistry changes, histopathology and DNA damage were evaluated. Results indicate that GSPE preexposure prior to the drugs/chemicals such as AP, AM, DX or DM treatment, provided near complete protection in terms of serum chemistry changes and inhibition of both forms of cell death, e.g., apoptosis and necrosis. DNA damage in various tissues triggered by these agents was significantly reduced in GSPE-fed animals. Histopathological examination of multiple target organs provided similar data. The results suggest that GSPE exposure is bioavailable and provides significant multiorgan protection against structurally diverse drug- and chemical-induced toxic assaults. Further, these studies exhibited a series of mechanistic information including free radical scavenging ability, anti-endonucleolytic activity, cytochrome P450 2E1 inhibitory activity, anti-necrotic, anti-apoptotic and anti-carcinogenic activities, modulatory effects on antioxidative and apoptotic regulatory genes such as Bcl2, c-myc and p53, which may be responsible for the novel chemoprotective properties exhibited by GSPE.