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Saturday 12 January 2019

Re: Herbal Products Reviewed for Their Cardiovascular Effects, Labeling, and Safety Concerns

Date: 07-13-2018 HC# 121733-596

Nunes MA, Rodrigues F, Alves RC, Oliveira MBPP. Herbal products containing Hibiscus sabdariffa L., Crataegus spp., and Panax spp.: Labeling and safety concerns. Food Res Int. October 2017;100(Pt 1):529-540. doi: 10.1016/j.foodres.2017.07.031.
Hibiscus (Hibiscus sabdariffa, Malvaceae), hawthorn (Crataegus spp., Rosaceae), and ginseng (Panax spp., Araliaceae) have been studied for their beneficial effects on cardiovascular health. They are the main ingredients in various herbal products, some of which claim to improve cardiovascular disease (CVD) risk factors such as hypertension and dyslipidemia. Concomitant use of medicines and herbal products may bear some risks. The authors reviewed herbal and herbal/fruit products available in Portugal containing hibiscus, hawthorn (C. monogyna), and Asian ginseng (P. ginseng); critically analyzed the product labels; assessed the cardiovascular effect of the products; and analyzed the current market for these products.
Products were randomly selected from six supermarkets and three herbalist shops in Porto, Portugal, during April and May 2016. Fifty-two products for infusion preparation, from 22 commercial brands, were found to contain herbs individually or in mixtures. Thirty included hibiscus, 16 contained hawthorn, and six contained Asian ginseng. For each product, the authors recorded label information about ingredients, plant part(s), form, and preparation recommendations. They evaluated statements or claims referring to health conditions and warnings for specific health or well-being disorders. Not all products specified the plant's scientific name. For 33 products, only the common name was used. For five products, although the product name referred to one plant, several plants were named as ingredients. Ten products did not list the main ingredient on the front label.
Of the total ingredients, proportions ranged from 1% in a mixture of ginseng, honey, lemon (Citrus × limon, Rutaceae), and green tea (Camellia sinensis, Theaceae), to 100% in three hibiscus products. Four products contained hibiscus extracts while none contained hawthorn or ginseng extracts. Nineteen products did not describe the amount of plant or plant part used.
A meaningful assessment of representative chemical constituents and plant effects is confounded by the variety of bioactive compounds found in these plants due to cultivation and climate conditions, plant genetics, metabolic pathways, harvesting practices, and method of analysis. Comparing studies of the plants is also impeded by varying sample preparation, solvents and sample/solvent ratios, method of extraction, and analytical methods used.
Hibiscus is used worldwide to treat hypertension and dyslipidemia. Hibiscus beverages are usually prepared by decoction or infusion of its calyxes and leaves. Its flowers contain phenolic acids, flavonoids, and anthocyanins. The calyxes have a lower content of flavonoids and glycosides. Various studies have evaluated the effects of hibiscus compounds on the cardiovascular system, with some investigators attributing its protective cardiovascular properties to its anthocyanins. Among the potential mechanisms for its antihypertensive, antioxidant, and hypolipidemic properties are direct effects on vascular muscles, calcium channels, and cholinergic and histaminic activity. Of the 30 products with hibiscus as the major ingredient, six products did not name the plant on the front label. The flower was the most common part listed, with only one product containing leaves. One product claimed tonic properties and improved circulation. Recommended dosages and preparation instructions were indicated on the labels.
Hawthorn is used in infusions, tinctures, standardized extracts, dietary supplements, authorized prescription drugs, and herbal medicinal products for its cardioprotective effects. Among the many bioactive compounds identified in the species are oligomeric procyanidins, flavonoids, catechins, and sugars, which are found in the berries, leaves, and flowers. The species' beneficial cardiovascular effects are attributed to their antioxidant, anti-inflammatory, antiplatelet aggregation, vasodilating, antiarrhythmic, lipid-lowering, and endothelial protective properties; positive inotropic action; reduced smooth muscle cell migration and proliferation; protection against ischemia/reperfusion injury; and a decrease of arterial blood pressure. The 16 samples in this study contained flowers, leaves, and fruits, up to a proportion of 35%. Five products included statements related to cardiovascular conditions, such as "supports the normal function of the arteries," "important for […] arrhythmias," and "supports cardiac function, increases the oxygen flow and improves peripheral circulation." The authors found some of these claims misleading.
Ginseng contains ginsenosides, a group of triterpene glycosides, which are present in the root, leaf, and berry. The various ginsenoside structures are associated with different mechanisms and pharmacological effects, probably due to their antioxidant, anti-inflammatory, immunostimulatory, and antihyperglycemic activities. Inconsistent study outcomes may be attributed to the structural heterogeneity of the ginsenosides, their multiple mechanisms, and the various experimental methodologies used to evaluate their activities. Fourteen products containing ginseng presented cautionary statements such as, "It is advisable to consult a doctor or a dietitian whenever you have questions about the consumption of this product" and "This tea should not be taken by individuals with low blood pressure."
European regulations stipulate that nutrition and health claims must be scientifically valid or proven, useful, reliable, and comprehensible to consumers. The European Medicines Agency’s monographs cover therapeutic uses and safe conditions of well-established and traditional applications for herbal preparations. Some statements and claims on products included in this study corresponded to EU herbal monographs.
The herbs described in this study "seem to have potential benefits for CVD and can draw the consumers' attention," write the authors. Of concern are consumers with a cardiovascular disorder, who are being treated with conventional medications, and who take herbs regularly, but do not know the herbs present in the products they take. A lack of information may lead to adverse effects from herb-drug interactions and other potential side effects. Although some adverse effects and herb-drug interactions have been reported, findings suggest only nonsignificant evidence of interactions between drugs and hibiscus. Hawthorn is well-tolerated and free from significant adverse effects. However, some adverse effects reported include headache, rash, palpitations, and gastrointestinal upset. It may also interact with antihypertensives, antilipemic drugs, beta-blockers, digoxin, vasodilators, anticoagulant, and antiplatelet drugs. Patients who consume ginseng products along with anticoagulants, antidepressants, antidiabetics, antilipemic drugs, calcium channel blockers, digoxin, or diuretics should be monitored. "[…] consumers with some sort of cardiovascular dysfunction and/or under medication treatments should be aware to carefully analyze the labels and consult additional information related to these herbal products," state the authors. Manufacturers should provide awareness statements, and health professionals should caution their patients about possible herb-drug interactions, according to the authors. Additional studies and clinical trials are needed to better understand the effects of herbs and to provide science-based guidance to assess their safety.

Shari Henson