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Guayusa- The Safety, Pharmacokinetics, and Nervous System Effects of Two Natural Sources of Caffeine in Healthy Adult Males



DR Krieger, 1 DS Kalman, 1 S Feldman, 1 L Arnillas, 1 D Goldberg, 1 O Gisbert, 1 and S Nader 1


This double‐blind crossover clinical trial randomized 12 adult males to receive 200 mg of caffeine from a green coffee extract, a guayusa leaf extract, and a synthetic control to compare their safety, absorption, and effect on neurotransmitters. The results showed no statistically significant changes in blood pressure or heart rate from baseline to 120 min postdose of each natural source compared with changes from baseline in the control (0.094 < = P < = 0.910). The ratios of Cmax, AUC0‐4, and AUC0‐∞ of each natural source to the control were bioequivalent by US Food and Drug Administration standards (90% CI within 80–125%). The guayusa leaf extract stimulated a significantly lower increase in epinephrine compared with the control (+0.5 vs. +2.78 μg/gCr, P = 0.04), while the green coffee extract provoked an increase in epinephrine similar to the control (+3.21 vs. +2.78 μg/gCr, P = 0.569). Implications for future clinical research are discussed.

Study Highlights


✓ The current research on this topic shows that natural sources of caffeine may have influences on the body similar to those of synthetic caffeine when absorbed in comparable doses.


✓ This study addressed the question of whether two natural sources of caffeine, green coffee extract and guayusa leaf extract, are safe to consume and what impact their consumption has on the body’s neurotransmitter system and vital signs compared with synthetic caffeine.


✓ This study has several implications for future clinical research on the safety and neurological impact of natural caffeine sources. The findings suggest that the natural caffeine extracts behave like synthetic caffeine with respect to their effect on the cardiovascular system and their pharmacokinetic absorption profiles. However, the guayusa leaf extract may be less stimulating to the release of epinephrine compared with the green coffee extract and synthetic caffeine, which has implications for its therapeutic applications and safety.


✓ This study generates a hypothesis for the future study of clinical applications for natural caffeine sources—that tea‐leaf sourced caffeine may have differential impacts on excitatory neurotransmitters, particularly the adrenaline response, from the previously studied effects of synthetic caffeine. In addition, this study adds to the FDA’s investigation of caffeine metabolism in conjunction with food substances, since it shows that natural sources of caffeine plus carbohydrates are absorbed similarly to synthetic caffeine.

Caffeine is one of the most common stimulants consumed worldwide and can originate from both plant‐based and synthetic sources.12 The average daily caffeine intake in the United States ranges between 210 and 238 mg per day, which can be consumed through a variety of dietary supplements, beverages, and food products.3 Although caffeine has historically not been regulated as a drug by government agencies, its diverse interactions with neurotransmitters in the brain have been shown to have both therapeutic and harmful effects. From a therapeutic perspective, caffeine’s role as an adenosine A2A antagonist has been linked to a lower risk of Parkinson’s disease and other neurodegenerative disorders such as Alzheimer’s disease.345 At the same time, caffeine’s stimulation of the body’s adrenaline response has been associated with acute increases in blood pressure and heart rate, although caffeine consumers seem to develop tolerance to these effects after prolonged regular consumption.67

As caffeine continues to be added to a growing number of food products, it has become increasingly important for regulatory bodies to understand the clinical implications of caffeine’s effect on the brain and the body. In recognition of this, the US Food and Drug Administration (FDA) announced in May 2013 that it would begin a coordinated effort to investigate the safety of caffeine.8 This includes an investigation into plant‐based caffeine sources, which have identical chemical structures to synthetic caffeine, but also contain other ingredients that may differentiate some effects of plant‐based caffeine from those of synthetic caffeine.9 Substances other than caffeine in natural sources such as coffee and green tea have been proposed as a mechanism linking caffeine consumption to a variety of health outcomes, from reduced rate of metabolic syndrome through lowered serum triglyceride levels, to increased performance on memory and attention tasks.1011

In response to the need for more research on the safety and neurological mechanisms of natural caffeine sources, the current study investigated the safety, pharmacokinetics, and nervous system effects of two natural sources of caffeine compared with a synthetic control: a green coffee extract (JAVA.g) that was derived from 100% green C. arabica and/or C. robusta coffee, and a guayusa (Illex guayusa) tea‐leaf extract (AMATEA). These extracts are intended as replacements for synthetic caffeine in general circulation. Consumption of each extract in quantities comparable to synthetic caffeine has been generally recognized as safe (GRAS) by a panel of independent experts based on data available and the intended use of the product,912 but there is no human clinical evidence to date examining the safety, pharmacokinetics, and nervous system effects of either caffeine source. This randomized, double‐blind, crossover clinical trial provides human clinical evidence of the safety, pharmacokinetics, and nervous system effects of a green coffee extract and a guayusa leaf extract in healthy adult males.



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Alternative Health

Ivermectin – Niacin Research



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Alternative Health

A review on phytochemistry and medicinal properties of the genus Achillea



  • Received 30 Apr 2011; Revised 2 July 2011; Accepted 2 July 2011

1Saeidnia S., *1Gohari AR., 1Mokhber-Dezfuli N, 2 Kiuchi F.
1 Medicinal Plants Research Center, Faculty of Pharmacy, Tehran University of Medical
Sciences, Tehran, Iran. 2 Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku,
Tokyo 105-8512, Japan.


Achillea L. (Compositae or Asteraceae) is a widely distributed medicinal plant throughout the world and has been used since ancient time. Popular indications of the several species of this genus include treatment of wounds, bleedings, headache, inflammation, pains, spasmodic diseases, flatulence and dyspepsia. Phytochemical investigations of Achillea species have revealed that many components from this genus are highly bioactive. There are many reports on the mentioned folk and traditional effects. Although, the medicinal properties of Achillea plants are recognized worldwide, there are only one review article mainly about the structures of the phytochemical constituents of Achillea. The present paper reviews the medicinal properties of various species of Achillea, which have been examined on the basis of the scientific in vitro, in vivo or clinical evaluations. Various effects of these plants may be due to the presence of a broad range of secondary active metabolites such as flavonoids, phenolic acids, coumarins, terpenoids (monoterpenes, sesquiterpenes, diterpenes, triterpenes) and sterols which have been frequently reported from Achillea species.

Keywords: Achillea, Asteraceae, Bioactive compounds.

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The genus Achillea L. belongs to Asteraceae (Compositae), the largest family of vascular plants. Asteraceaeous plants are distributed throughout the world and most common in the arid and semi-arid regions of subtropical and lower temperate latitudes. Achillea contains around 130 flowering and perennial species and occurs in Europe and temperate areas of Asia and a few grow in North America. These plants typically have hairy and aromatic leaves and flat clusters of small flowers on the top of the stem. Since these flowers have various colors, a number of species are popular garden plants (14). The basic chromosome number of this genus is X=9 and most of the species are diploid with great ecological ranges from desert to water-logged habitats (5).

The name of Achillea is referred to the Achilles in the literary Trojan War of the Iliad who used yarrow to treat the soldiers’ wounds (6). The majority of the Achillea species are as the medicinal plants which have therapeutic applications (4). There are few review papers on the different aspects of Achillea as a noteworthy and medicinal genus. Recently, Si and co-authors (7) published a review article mainly about the structures of phytochemical constituents and a brief section of biological properties of Achillea (7). Literature reviews show that there are many reports on pharmacological, immunological, biological and other therapeutic activities of these valuable herbs which are reviewed in this article.

Traditional usages 

Since Achillea genus is widespread all over the world, its species have been used by local people as folk or traditional herbal medicines. Bumadaran is a popular name for several species of Achillea in Persian language. They are reported as tonic, anti-inflammatory, anti-spasmodic, diaphoretic, diuretic and emmenagogic agents and have been used for treatment of hemorrhage, pneumonia, rheumatic pain and wounds healing in Persian traditional literature (89).

In Spanish-speaking New Mexico and southern Colorado, A. millefolium L. is called plumajillo, or “little feather”, because of the shape of the leaves. Native Americans and early settlers used yarrow for its astringent qualities that made it effective in wound healing and anti-bleeding (10).

Achillea species are the most important indigenous economic plants of Anatolia. Herbal teas prepared from some Achillea species are traditionally used for abdominal pain and flatulence in Turkey (11). Dioscorides also used Achillea for dysentery, whether associated with cholera or other causes, which killed as many soldiers as did steel and lead. In terms of Chinese medicine, Achillea can be said to have three main actions: clear Exterior Wind (diaphoretic), Tonify Deficiency (tonic) and clear Heart Phlegm (anti-hypertention) (12).

Many of these therapeutic usages have been confirmed by new experimental and clinical studies. The consumption of herbal teas from different species of Achillea, especially for treatment of the gastrointestinal tract, is common in folk medicine (13). However, there are still several unknown aspects of Achillea plants that need more attention.

Phytochemical constituents 

Phytochemical investigations of Achillea species have revealed that many components from this genus are highly bioactive. The first anti-spasmodic flavonoids, cynaroside I and cosmosiin II (Scheme 1) were isolated from A. millefolium L. (14), and the first natural proazulene, achillicin III (Scheme 2) was identified from the genus Achillea (15). Literature search shows that the, flavonoids, terpenoids, lignans, amino acid derivatives, fatty acids and alkamides such as p-hydroxyphenethylamide IV (Scheme 2) have been identified in Achillea species. The main constituents of the most species have been previously reviewed (7). Therefore, in this article some other minor or rare compounds and especially their medicinal or industrial usages which have been less described are reviewed. Among them,alkamides, the lipophilic and nitrogen containing compounds, are responsible for insecticide, anti-inflammation and some immunological activities of Achillea and Echinacea plants (16). The genus Achillea comprises flavored species which produce intense essential oils. The volatile oils of Achillea contain monoterpenes as the most representative metabolites. However, there are reports on high levels of sesquiterpenes compared with monoterpenes (1718). There are several pharmacological actions which have been mostly attributed to the presence of azulenogenous sesquiterpene lactones in the essential oil of Achillea. Results of studies have indicated that tetraploid species are accumulating proazulenes such as achillicin III (Scheme 2) (19).Except for the essential oil constituents, yarrow (A. tenuifolia Lam.) seeds consist of the high oil content which is rich in linoleic acid, an essential polyunsaturated fatty acid. This makes yarrow seed as a potential source of edible oil for human consumption (20). Recently, A. millefolium has been introduced as a new source of natural dye for wool dyeing due to the presence of the flavonoids, luteolin V and apigenin VI (Scheme 1). A. millefolium was found to have good agronomic potential as a natural dye in Iran (21). In the plant kingdom, hydroxycinnamoyl conjugates of quinic acid represent common end metabolites of the shikimate-phenylpropanoid pathway, and feruloylcaffeoylquinic acid derivates VII have been isolated only from two species of genus Achillea so far (22). From the aerial parts of Achillea species, proline VIII, stachydrine IX, betonicine X, betaine XI and choline XII have been isolated as the major nitrogen containing compounds (Scheme 2) (2324). Betaines, containing the permanent positive charge on the quaternary ammonium moiety, belong to an important class of naturally occurring compounds that function as compatible solutes or osmoprotectants (25). These compounds have shown immunosuppressive activity in the experimental animals (2627).



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Yerba Mate (Ilex paraguariensis) Beverage: Nutraceutical Ingredient or Conveyor for the Intake of Medicinal Plants? Evidence from Paraguayan Folk Medicine



Monika Kujawska


The use of medicinal plants mixed with yerba mate (Ilex paraguariensis) has been poorly studied in the ethnopharmacological literature so far. The Paraguayan Mestizo people have the longest tradition of using the yerba mate beverage, apart from the indigenous Guarani people. This study analyses the role of yerba mate and medicinal plants in the treatment of illnesses within Paraguayan folk medicine. The research was conducted among 100 Paraguayan migrants living in Misiones, Argentina, in 2014 and 2015. Yerba mate is not considered to be a medicinal plant by its own virtues but is culturally a very important type of medicinal plant intake. Ninety-seven species are employed in hot and cold versions of the yerba mate beverage. The most important species are as follows: Allophylus edulis (highest number of citations), Aristolochia triangularis (highest relative importance value), and Achyrocline flaccida and Achyrocline tomentosa (highest score by Index of Agreement on Species). The plants are used in the treatment of 18 medicinal categories, which include illnesses traditionally treated with plants: digestive system, humoral medicine, and relatively new health conditions such as diabetes, hypertension, and high levels of cholesterol. Newly incorporated medicinal plants, such as Moringa oleifera, are ingested predominantly or exclusively with the mate beverage.

1. Introduction

Yerba mate (Ilex paraguariensis A.St.-Hil., Aquifoliaceae) is a native tree growing in the subtropics of South America, present in Southern Brazil, Northeastern Argentina, Eastern Paraguay, and Uruguay [1]. The yerba mate beverage has been consumed traditionally by Guarani indigenous people since before the conquest of South America by the Spaniards [2]. The commercial potential of this plant was discovered by the Jesuits, who brought wild growing yerba mate into cultivation. Pedro de Montenegro, a Jesuit monk, in his Materia Medica Misionera described the use of the most important species for the Guarani people, in which yerba mate appeared on the top of the list [3]. The Guarani name for yerba mate is ka’a which means “a plant” or “a herb”; hence yerba mate has been considered by this group as the plant par excellence [3]. Yerba mate was also known as Jesuit tea or Paraguayan tea and shipped as such to Europe [2]. With the expulsion of the Jesuits in 1768, the plantations went wild. By this time, the yerba mate beverage was already popular among Mestizo people (of Spanish and Guarani origin). Since the end of the 19th century, it also became a daily beverage for the European migrants who partly colonized Southern Brazil, Northeastern Argentina, and, to a lesser extent, Eastern Paraguay [4]. Nowadays yerba mate is consumed at the rate of more than one litre per day by millions of people in the above-mentioned countries [45]. It plays a very special social role and constitutes a very important form of caffeine intake [245]. Its popularity is also increasing outside South America due to its pharmacological properties, proven to be beneficial to health [467]. It is also a very important drink in Syria and Lebanon due to Syro-Lebanese migration to Argentina in the second half of the 19th century. Many migrants who returned to the Levant in the 1920s took the habit of drinking mate with them [89].

Over the last 20 years there has been an increase in studies of the pharmacologic properties of Ilex paraguariensis, which have been reviewed [46710]. Numerous active compounds have been identified in yerba mate. Phenolic compounds predominate caffeoyl derivatives (caffeic acid, chlorogenic acid) [1112], xanthines (caffeine and theobromine), which are a class of purine alkaloids found in many other plants such as tea and coffee, flavonoids (quercetin, kaempferol, and rutin), and tannins [7]. Numerous triterpenoid saponins have also been identified, including those derived from ursolic acids known as metasaponins [47]. Saponins are responsible for the distinct flavour of yerba mate extracts [7]. Yerba mate also contains minerals (P, Fe, and Ca) and vitamins (C, B1, and B2) [13].

Research on extracts and isolated compounds from yerba mate has provided a number of pharmacological applications. Studies have demonstrated that yerba mate leaves have antioxidant [11], antiobesity [1415], antidiabetic, digestive improvement and cardiovascular properties [1617], and chemopreventative ones (preventing cellular damage that may cause chronic diseases) [18]. The consumption of yerba mate infusion reduces LDL-cholesterol in parallel with an increase in HDL-cholesterol, as observed in studies on humans [19]. Yerba mate extract also reduces acute lung inflammation, as observed in the animal model [4]. Antimicrobial activity of Ilex paraguariensis has been recently studied as well [20].

Some ethnobotanical studies from the south cone of South America report medicinal uses of yerba mate beverage [2122]. Few ethnobotanical and ethnopharmacological studies mention that various medicinal plants are consumed together with the yerba mate beverage by Mestizo and European migrants living in Argentina and Paraguay [2326]. However, very little is known about how medicinal plants are combined with yerba mate beverage by local people. Additionally, medicinal plant use by Paraguayan Mestizo people is poorly documented in the English-language scientific literature, with very few exceptions [232630]. The documentation of medicinal plants and analysis of traditional knowledge related to the yerba mate beverage by Paraguayan Mestizo people is of paramount importance for two reasons: (1) apart from indigenous Guarani peoples, they have the longest tradition of using yerba mate and mixing it with medicinal plants; (2) The Paraguayan people are described in the literature as knowledgeable about medicinal plants [3031]. Nearly 80% of the population of Paraguay consume medicinal plants on a daily basis [30]. However, the relationship between traditional uses and pharmaceutical properties is poorly studied.

The objectives of this contribution were to (1) document and analyse the role of yerba mate in prophylaxis and treatment by Paraguayan Mestizo people; (2) evaluate the role of medicinal plants in yerba mate beverages, and (3) describe the scope of illnesses treated with yerba mate beverage and medicinal plants. Additionally, two questions guided my research and analysis: (1) Does any pattern exist showing that particular illnesses are treated with a hot version of yerba mate beverage and others with a cold one? (2) How receptive is this traditional mode of plant administration to new health challenges and new medicinal plants, previously unknown to the Paraguayan people?



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