Cardiovascular toxicity of Citrus aurantium in exercised rats.

When safety concerns forced the removal of ephedra from the market, other botanicals, including Citrus aurantium or bitter orange (BO) were used as replacements. A major component of the BO extract is synephrine, a chemical that is structurally similar to ephedrine. Because ephedrine has cardiovascular effects that may be exacerbated during physical exercise, the purpose of this study was to determine whether extracts containing synephrine produced adverse effects on the cardiovascular system in exercising rats. Sprague-Dawley rats were dosed daily by gavage for 28 days with 10 or 50 mg of synephrine/kg body weight from one of two different extracts; caffeine was added to some doses. The rats ran on a treadmill for 30 min/day, 3 days/week. Heart rate, blood pressure, body temperature, and QT interval were monitored. Both doses of both extracts significantly increased systolic and diastolic blood pressure for up to 8 h after dosing. Effects on heart rate and body temperature appeared to be due primarily to the effects of caffeine. These data suggest that the combination of synephrine, caffeine, and exercise can have significant effects on blood pressure and do not appear to be effective in decreasing food consumption or body weight.

Physiological effects following administration of Citrus aurantium for 28 days in rats.

BACKGROUND: Since ephedra-containing dietary supplements were banned from the US market, manufacturers changed their formulations by eliminating ephedra and replacing with other botanicals, including Citrus aurantium, or bitter orange. Bitter orange contains, among other compounds, synephrine, a chemical that is chemically similar to ephedrine. Since ephedrine may have cardiovascular effects, the goal of this study was to investigate the cardiovascular effects of various doses of bitter orange extract and pure synephrine in rats. METHOD: Female Sprague-Dawley rats were dosed daily by gavage for 28 days with synephrine from two different extracts. One extract contained 6% synephrine, and the other extract contained 95% synephrine. Doses were 10 or 50mg synephrine/kg body weight from each extract. Additionally, caffeine was added to these doses, since many dietary supplements also contain caffeine. Telemetry was utilized to monitor heart rate, blood pressure, body temperature and QT interval in all rats. RESULTS AND CONCLUSION: Synephrine, either as the bitter orange extract or as pure synephrine, increased heart rate and blood pressure. Animals treated with 95% synephrine showed minimal effects on heart rate and blood pressure; more significant effects were observed with the bitter orange extract suggesting that other components in the botanical can alter these physiological parameters. The increases in heart rate and blood pressure were more pronounced when caffeine was added. None of the treatments affected uncorrected QT interval in the absence of caffeine.

Developmental toxicity of Citrus aurantium in rats.

BACKGROUND: Ephedra was commonly used in herbal products marketed for weight loss until safety concerns forced its removal from products. Even before the ban, manufacturers had begun to replace ephedra with other compounds, including Citrus aurantium, or bitter orange. The major component in the bitter orange extract is synephrine which is chemically similar to ephedrine. The purpose of this study was to determine if relatively pure synephrine or synephrine present as a constituent of a bitter orange extract produced developmental toxicity in rats. METHOD: Sprague-Dawley rats were dosed daily by gavage with one of several different doses of synephrine from one of two different extracts. Caffeine was added to some doses. Animals were sacrificed on GD 21, and fetuses were examined for the presence of various developmental toxic endpoints. RESULTS AND CONCLUSION: At doses up to 100 mg synephrine/kg body weight, there were no adverse effects on embryolethality, fetal weight, or incidences of gross, visceral, or skeletal abnormalities. There was a decrease in maternal weight at 50 mg synephrine/kg body weight when given as the 6% synephrine extract with 25 mg caffeine/kg body weight; there was also a decrease in maternal weight in the caffeine only group. This decrease in body weight may have been due to decreased food consumption which was also observed in these two groups. Overall, doses of up to 100 mg synephrine/kg body weight did not produce developmental toxicity in Sprague-Dawley rats.

The state of dietary supplement adverse event reporting in the United States.

PURPOSE: The Dietary Supplements Information Expert Committee (DSI-EC; the Committee) of the United States Pharmacopeial Convention (USP) reviews safety profiles of dietary supplements before development of USP-National Formulary (USP-NF) quality monographs. Because the veracity of dietary supplement adverse event reports (DS AERs) directly affects DSI-EC safety reviews, the Committee reviewed the current status of DS AER reporting in the US. METHODS: DSI-EC reviewed PubMed searches, information from the US Food and Drug Administration's (FDA) MedWatch program, the Toxic Exposure Surveillance System (TESS) of the American Association of Poison Control Centers (AAPCC), and reports from US and other agencies. DSI-EC analyzed this information to identify key factors that affect the quality of DS AERs. RESULTS: The overall incidence of DS AERs appears generally to be low. However, the primary reporting portal (FDA MedWatch) receives fewer AERs than do poison control centers (PCCs), and limited coordination exists among national and international surveillance programs for evaluating signals that may indicate potential public health risks. Both inadequate and poor-quality reporting of DS AERs are major limitations of DS safety monitoring in the US. CONCLUSIONS: Based on its assessments, the Committee advances recommendations to improve the quality of reporting, monitoring, and assessing DS AERs. These include (1) enhanced data collection approaches, (2) improved coordination of AER surveillance programs, (3) strengthening of educational programs for public and health care sectors, and (4) conduct of research concerning the safety of DS. If taken, these approaches are expected to improve the health and well-being of DS users.

Safety of green tea extracts : a systematic review by the US Pharmacopeia.

Green tea [Camellia sinensis (L.) Kuntze] is the fourth most commonly used dietary supplement in the US. Recently, regulatory agencies in France and Spain suspended market authorization of a weight-loss product containing green tea extract because of hepatotoxicity concerns. This was followed by publication of adverse event case reports involving green tea products. In response, the US Pharmacopeia (USP) Dietary Supplement Information Expert Committee (DSI EC) systematically reviewed the safety information for green tea products in order to re-evaluate the current safety class to which these products are assigned. DSI EC searched PubMed (January 1966-June 2007) and EMBASE (January 1988-June 2007) for clinical case reports and animal pharmacological or toxicological information. Reports were also obtained from a diverse range of other sources, including published reviews, the US FDA MedWatch programme, USP's MEDMARX adverse event reporting system, the Australian Therapeutic Goods Administration, the UK Medicines and Healthcare products Regulatory Agency, and Health Canada's Canadian Adverse Drug Reaction Monitoring Program. Case reports pertaining to liver damage were evaluated according to the Naranjo causality algorithm scale. In addition, the Committee analysed information concerning historical use, regulatory status, and current extent of use of green tea products. A total of 216 case reports on green tea products were analysed, including 34 reports concerning liver damage. Twenty-seven reports pertaining to liver damage were categorized as possible causality and seven as probable causality. Clinical pharmacokinetic and animal toxicological information indicated that consumption of green tea concentrated extracts on an empty stomach is more likely to lead to adverse effects than consumption in the fed state. Based on this safety review, the DSI EC determined that when dietary supplement products containing green tea extracts are used and formulated appropriately the Committee is unaware of significant safety issues that would prohibit monograph development, provided a caution statement is included in the labelling section. Following this decision, USP's DSI ECs may develop monographs for green tea extracts, and USP may offer its verification programmes related to that dietary ingredient.

United States Pharmacopeia review of the black cohosh case reports of hepatotoxicity.

OBJECTIVE: Black cohosh [Actaea racemosa L., formerly Cimicifuga racemosa (L.) Nutt.] is a botanical used mainly for the management of menopausal symptoms. Recently, regulatory agencies in Australia, Canada, and the European Union have released statements regarding the "potential association" between black cohosh and hepatotoxicity. In response, the Dietary Supplement Information Expert Committee of the US Pharmacopeia's Council of Experts reviewed safety information for black cohosh products. DESIGN: The Expert Committee analyzed information from human clinical case reports, adverse event reports, animal pharmacological and toxicological data, historical use, regulatory status, and contemporaneous extent of use. Reports were obtained from diverse sources, including the European Medicines Agency, Health Canada, the Australian Therapeutic Goods Administration, and the US Food and Drug Administration. Case reports pertaining to liver damage were evaluated according to the Naranjo causality algorithm scale. RESULTS: Thirty nonduplicate reports on use of black cohosh products concerning liver damage were analyzed. All the reports of liver damage were assigned possible causality, and none were probable or certain causality. The clinical pharmacokinetic and animal toxicological information did not reveal unfavorable information about black cohosh. CONCLUSIONS: Based on this safety review, the Dietary Supplement Information Expert Committee determined that black cohosh products should be labeled to include a cautionary statement. This is a change from the Expert Committee's decision of 2002, which required no such statement. With this decision, the US Pharmacopeia's Botanical Expert Committee may develop monographs for black cohosh, and the US Pharmacopeia may offer its verification programs to dietary supplement ingredient and product manufacturers.