Guarana (Paullinia cupana)
What is Guarana?
Guarana is a shrub found growing in the amazon rainforest of South America. It's a member of the Sapindaceae family of plants which includes such members as the maple tree, horse chestnut, and lychee.
The seeds of the guarana tree contain the highest known source of caffeine, which is the source of much of its actions medicinally.
Local indigenous populations in the region used guarana as a stimulant on long hunting trips, or in social settings. In the modern world, guarana is used as a tonic for the cardiovascular system, and as a stimulating adaptogen.
Guarana supplementation is popular among athletes and students for its ability to increase the threshold for mental and physical exhaustion.
What is Guarana Used For?
Guarana contains a high amount of caffeine and is therefore used in a similar way to coffee. It is a CNS stimulant useful for improving energy, increasing mental work capacity, and can be used in the treatment of altitude sickness.
Guarana is also an adaptogen, stimulating as it may be. It’s useful for mood and concentration, increasing the ability to resist stressful stimuli, treating cardiovascular conditions like atherosclerosis and hypertension, improves digestive tone, and is a popular weight loss supplement.
Traditional Uses of Guarana
+ Traditional Amazonian Medicine
In the Amazon, various indigenous cultures have used this herb as a stimulant, astringent, analgesic, febrifuge, general tonic. It’s used for diarrhea, hypertension, migraines, neuralgia, dysentery, and more modernly to prevent cardiovascular disease [1].
The Satere-Mawe Indians used a mortar and pestle to grind the seeds, then mixed with water to form a paste, which was then shaped into cylinders and sun-dried. This formed a sort of “stick” which was usually then smoked and could last upwards of a year and preserved the characteristics of the plant quite well.
A study conducted on the effects on health associated with long term consumption of guarana noticed a significantly higher prevalence of males ingesting guarana long term over females. These researchers suggested this may be due to the indications for guarana in this region (Maue Brazil) being as an aphrodisiac, and to decrease fatigue, combined with the labor-intensive work of fishing, and agricultural work most often conducted by males.
The Satere-Mawe are most often associated with this botanical historically and referred to the beverage as Çapó. This was drunk by women during their period, while pregnant, and after giving birth. The males consumed this beverage during festivals, in mourning, before hunting trips, and after their wives gave birth.
+ Jesuits
The Jesuit’s expedition into South America revealed the first reports of guarana to the outside world in 1669 when the missionary João Felipe Bettendorf recorded the use of the herb by the Satere-Mawe Indians [5].
Herb Details: Guarana
Botanical Information
Guarana is a member of the Sapindaceae family of plants, which contains roughly 138 genera and 1858 species. Some other notable members of this family include maple, horse chestnut, lychee, longan, soapberry, and ackee.
Paullinia cupana is a creeping shrub indigenous to South America. There are a few varieties of guarana found throughout the Amazon rainforest, Paullinia cupana var. Typica — also referred to as Venezuelan guarana), P. cupana var. Sorbillis (a Brazilian variety). The Brazilian variety is the most commonly exported and is the variety that is most studied [5].
The word guarana, uarana, and varana mean “vine” in various indigenous dialects. The name refers to the growth habit of the plant — which has tendrils that can grow up to 10m in length and uses other rainforest trees to support itself on.
The leaves are alternate and odd-pinnate. The leaflets are oval and serrated, and glossy on top with a venous bottom.
Guarana is a monoecious plant, the racemes can contain up to 95 flowers, and are around 30cm in total length, containing small zygomorphic flowers. The calyx of each flower contains five sepals, with a white corolla consisting of 4 petals. Each flower is pseudo-hermaphrodite, and most (4.5:1) are male flowers, though this varies plant to plant [5].
The fruit is in the form of a capsule, starting dark green, and as it ripens becomes more yellow-orange, or yellow-red in color and sometimes can be found bright red. The seeds are dark brown, with a strikingly white aril. This gives the seed the appearance of an eye, which has been the subject of a few local legends and provides a robust identifying feature of the plant.
The guarana seed has roughly 4-5 times the amount of caffeine as Coffea arabica (2.5-8%) [5].
Guarana is very commonly used in soft drinks, energy drinks, cosmetic applications, pharmaceuticals, and as elixirs or capsules marketed for such purposes as weight loss, and energy supplements, such as for athletic enhancement purposes [5].
Habitat, Ecology, Distribution:
P. cupana is indigenous to tropical and subtropical South America and grows abundantly throughout the Amazon rainforest.
It is cultivated in various areas throughout the region. However, most production comes from Brazil, specifically in the states of Amazonas and Bahia (which combined produces 95% of production in Brazil) [5]. The rough cost of this herb from these farmers is R$ 7.45/kg (Amazonia), and R$5.90 (Bahia). Schimpl et al., (2013) reports that although the need for guarana is growing as the herb becomes more well known, production land has not grown much in the last ten years, but suggests that before this happens, there is room to increase the productivity of these current farms. Much of the reason behind the low productivity in this region is due to low technical qualifications by farmers, who mainly consist of small scale farms, with unskilled laborers.
The method of seed dispersal is generally by way of birds.
The high caffeine (and other purine alkaloids) content is generally thought to be a chemical defense mechanism against herbivores. The lack of alkaloids in the aril of the seeds, and habit by which birds eat the seed without breaking, or fully digesting the seeds, prevents the alkaloids from exiting the seed and causing toxicity to the birds, while also providing sugar to the birds via the alkaloid-free, sugary aril. Later, the seed is deposited intact where it may then attempt to germinate [5].
Harvesting, Collection, and Preparation:
Guarana fruit, ripens at different times along the same inflorescence, which makes harvesting fairly labor intensive, as it needs to be hand-picked often to gather only the ripe berries. This can take up to 3 months to complete. The plants can start being harvested yearly after about year 3, and produces large amounts of seed from about year 6 and on [5].
Guarana — like coffee (Coffea spp.), tea (Camellia sinensis), yerba maté (Ilex paraguariensis), and cacao (Theobroma cacao), which all contain similar xanthine alkaloids, are usually heated (roasted) and ground into a powder before use.
Guarana seeds are also sometimes fermented for a few days before retrieving the seeds from the fruit (very similar process to Theobroma cacao).
Mechanical processing usually skips this fermentation step and strips the seeds while fresh. The seeds are then dried once more in large pots, slowly over the course of a few hours, to avoid burning. This similarity in processing for botanicals containing the same xanthine alkaloids from various cultures around the world suggests the need for further investigation on what differences these plants contain without this heating process, in accordance with how they are traditionally used as stimulants.
In a patent outlined by Coca-Cola, the seeds are ground to a powder and extracted using 40-60% alcohol solution, and then concentrated through various processes. Separately, there exist methods by which the tannins are largely broken down, resulting in a concentrate with high caffeine, and low tannin. This process is used in the manufacture of energy drinks to avoid the brown color associated with its use, which is, in fact, a visual indication of the oxidation that has already occurred due to a complex hydrophobic interaction of tannin and caffeine [5].
Pharmacology & Medical Research
+ Adaptogen
Two long term studies of P. cupana on rodents using low dose administration of the extract (9 months at 3 mg/kg) was able to improve swimming time of the mice and reversed performance deficits in rats. This was suggested to be a benefit of more than just the caffeine content because it was found in low concentrations in this dose and produced stronger results than the larger (30 mg/kg) dose. Both extracts, however, reversed scopolamine-induced cognitive deficits. The suggested constituents responsible for this action is the tannin, and saponin contents [1]. Saponins, in particular, are strongly associated with adaptogenic and various other effects. Saponins are be defined as "high molecular weight glycosides combining a sugar element and a steroid aglycone or triterpene molecule" [4].
The caffeine contained in P. cupana is reported to be between 4% and 8% in the seeds. Caffeine has been the subject of many studies on cognitive function, and other effects. With a half-life of only 6 hours, these acute effects may need to be continually consumed to achieve any adaptogenic effects [6].
Guarana has also been reported that xanthine alkaloids do not build up in the body. This is on track with other xanthine alkaloid containing "adaptogens" such as yerba mate. Where both traditionally, and modernly, this beverage is consumed throughout the day, often over long periods.
The frequent use of Paullinia cupana was associated with lower rates of hypertension, obesity, and metabolic syndrome in seniors compared with those that did not take the botanical [5].
Though suggested to produce cognitive improvement and adaptogenic effects during long term use, there exists conflicting evidence in this area.
Particularly noted with the effects of long term use of this botanical on cognitive function. One study reportedly showed no significant cognitive improvement in elderly volunteers taking guarana long term, though how long is unknown by the author [6]. An improvement in cognitive function was noted after five days at a dose of 1080 mg/day taken just after breakfast [6].
More research is needed to understand further why these contradictory results have been obtained. Perhaps it could be in the amount of processing, such as roasting, and fermenting, and how much the plant has oxidized, that account for this difference in findings.
+ Atherosclerosis
An aqueous extract of P. cupana inhibited platelet aggregation, which is suggested to be due to the procyanidin, and catechin content in the extract [5]. Catechins are also contained in high amounts in Camellia sinensis and are well studied as having antiatherosclerotic effects from that plant.
+ Antibacterial
The ethanol extract of Paullinia cupana seeds showed antibacterial effects against both gram-negative, and gram-positive bacteria. Most notably Pseudomonas aeruginosa, Proteus mirabilis, Proteus vulgaris, and Escherichia coli [1].
+ Antioxidant
P. cupana has been shown in multiple studies to produce strong antioxidant effects. These effects were suggested to be due to the polyphenol content in the seeds, most notably catechol, as well as other catechins and epicatechins (flavonoids) [1].
+ Memory
Guarana was shown to partially reverse scopolamine-induced amnesia in mice [1]. This is most likely due to the antioxidant profile of guarana.
+ Depression
The antidepressant effects of guarana are thought to be due to its xanthine alkaloid content, which has been shown many times to improve symptoms involved with depression, though it should be noted that very few studies have looked thoroughly at the effects of caffeine and other xanthine alkaloids on mood specifically. [6].
+ Hypertension
The antihypertensive effects of guarana were noticed in a study done on the effects of long term consumption of guarana by Brazilian seniors. This study [2] noted that the alkaloid caffeine has been shown to increase blood pressure, but also noted the low incidence of test subjects in the chronic guarana consumption group over the group that did not consume guarana. These researchers suggested that this contradiction could be due to the development of tolerance to caffeine, which once achieved, allows caffeine consumption to take place without any increase in blood pressure.
+ Cardioprotective
Has been shown to inhibit platelet aggregation, as well as promote weight loss, which in turn lowers the chances of developing cardiovascular diseases [2]. Other factors are likely due to the antioxidant effects, and vasodilatory effects of guarana.
C. da Costa Krewer et al., (2011) reports of a study that investigated the relationship between caffeine consumption and cardiovascular events. The results of this study reported that there is a significant reduction in cardiovascular events (heart valve disease, cardiovascular mortality) associated with caffeine consumption in patients without moderate or severe hypertension. This same study also refers to a study that found that the reduction of sugar in such beverages as coffee, also resulted in a decrease in blood pressure, but noted no relationship between caffeine consumption and blood pressure. This is important to note because much of the guarana "health drinks" being sold around the world contain large amounts of sugar.
The tannins and related gallotannins contained in green tea, which are also contained within guarana, have been shown to inhibit Ca2+ activated Cl- channels (CACC). These potent CACC inhibitory effects are suggested to provide strong cardioprotective, as well as antisecretory effects [2].
+ Cancer
Researchers investigated the chemoprotective effects of P. cupana and reported that the botanical was able to provide chemoprotective effects, controlling the growth of melanomas in vivo. These effects were noted to be through a reduction in cancer cell proliferation and increased apoptosis. [7].
+ Gastric Tonic
Guarana has been shown to produce protective effects against gastric lesions, which is suggested to be due to its polyphenol content (caffeic acid, gallic acid, tannic acid) [1].
+ Psychoactive Effects
The xanthine alkaloids contained in guarana have all been shown to produce psychoactive effects (SOURCES). These alkaloids can freely pass the blood-brain barrier to exert their effects (SOURCE). In guarana, caffeine is by far in the highest concentration of these alkaloids. One study, however, showed that this was not the only psychoactive constituent of guarana, by evaluating the effects of low dose guarana, and pure caffeine (containing 16 times the amount of caffeine than the guarana dose), which resulted in the same effects on fatigue and memory tasks [4].
+ CNS Stimulant
Guarana contains xanthine alkaloids (especially caffeine) which are well-known stimulants. It has been shown to acutely improve cognitive performance, enhance secondary memory performance, increase alertness, and attenuates mental fatigue associated with extended task performance. It was also shown to combat the fatigue associated with chemotherapy; however, did not affect radiation-induced fatigue. Caffeine has a half-life of about 5-6 hours in the body, and therefore the stimulating effects produced by these chemicals may expire in this time [6].
+ Weight Loss
Guarana has been shown to produce positive effects on both lipid metabolism, and increase basal energy expenditure [2]. Both of which play a role in weight loss. Obesity is also associated with increased activity of the renin-angiotensin-aldosterone pathway (a hormonal system regulating blood pressure and fluid balance) [2]. Therefore the same activity guarana produces on preventing, and possibly reducing hypertension, may also play a role in its effects on obesity. Obesity is also associated with various processes of the sympathetic nervous system, as well as with mineralocorticoid activity, and insulin resistance, and reduced kidney function [2]. This suggests that the diuretic activity of guarana may also provide beneficial actions in the mechanism of weight loss, and preventing or treating obesity.
Guarana, mixed with Ilex paraguariensis, and Turnera diffusa, were used in powdered, capsule form (95 mg guarana, 112 mg yerba mate, 35 mg damiana), and shown to produce a 53% increase in gastric emptying times, and created a noticeable body weight reduction after 45 days in vivo compared to placebo control group [5].
Another study showed that guarana mixed with Ephedra sinica (40 mg P. cupana, 12 mg Ephedra sinica), at six tablets/day showed a significant reduction in serum triglyceride levels, hip circumference, and weight loss, over the eight-week duration of the study, as compared to the placebo group [5].
Another study combining 200 mg caffeine from guarana, and 90 mg EGCG from Camellia sinensis found an increase in energy expenditure, however also produced a slight increase in blood pressure, and lack of a reduction in lipid oxidation [5]. These results suggest the caffeine, and EGCG is not the only active ingredients in guarana combined with camellia sinensis.
Phytochemistry
Guarana contains xanthic acids, including caffeine, theobromine, and theophylline. The seeds only contain caffeine, whereas all three are found in the bark, leaves, and flowers. In the seed, the aril was noted to be almost alkaloid-free, whereas the seed kernel and seed coat contained a high concentration of alkaloids (namely caffeine) [1].
The seeds of guarana also contain large amounts of polyphenols, such as tannins. These tannins are primarily in the form of condensed tannins, or proanthocyanidins, with a high incidence of catechins, and epicatechins, which are mainly held responsible for the antioxidant activity of the seeds [5].
Saponins are also contained within guarana, though in small amounts [5].
The constituents of guarana include starch (60 g/100g), tannin (8.5-9.5 g/100g), protein (7.5-8.5 g/100g), soluble sugars (8g/100g), reducing sugars (2.3-4.9g/100g), caffeine (3.2-3.8g/100g), fiber (2.4-3.2g/100g), pentosan (0.2-0.6 g/100g), ash (1.4-2.1 g/100g), humidity (8.75-10.5 g/100g). In the oil of guarana seed contains methyl benzenes, cyclic monoterpenes, sesquiterpenes, oleic acid, paullinic acid and methoxyphenyl propene [5].
Clinical Applications Of Guarana:
Guarana is useful as a stimulating adaptogen to improve conditions like chronic fatigue, hypothyroidism, and debilitating conditions that have not reached convalescence. It is useful as a source of caffeine for mental cognitive enhancement, in nootropic applications, and as a replacement for coffee.
Guarana is also useful for cardiovascular conditions if used long term. The initial spike in blood pressure and anxious side effects need to be overcome through adenosine receptor tolerance before these effects can be delivered. Therefore, guarana can be used as a cardioprotective against hypertension, angina, and atherosclerosis, but only in people that have not reached a high level of cardiovascular degeneration. Guarana is not recommended in those with significantly high blood pressure or who are suffering from severe CHF, COPD, or Angina.
+ Contraindications
- Hypertension
- Over-stimulation
- Anxiety
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References:
Basile, A., Ferrara, L., Del Pezzo, M., Mele, G., Sorbo, S., Bassi, P., & Montesano, D. (2005). Antibacterial and antioxidant activities of ethanol extract from Paullinia cupana Mart. Journal of ethnopharmacology, 102(1), 32-36.
Costa Krewer, C., Ribeiro, E. E., Ribeiro, E. A. M., Moresco, R. N., Ugalde Marques da Rocha, M. I., Montagner, S., ... & Cruz, I. B. M. (2011). Habitual intake of guaraná and metabolic morbidities: an epidemiological study of an elderly Amazonian population. Phytotherapy research, 25(9), 1367-1374.
BROKEN SOURCE.
Kennedy, D. O., Haskell, C. F., Wesnes, K. A., & Scholey, A. B. (2004). Improved cognitive performance in human volunteers following administration of guarana (Paullinia cupana) extract: comparison and interaction with Panax ginseng. Pharmacology Biochemistry and Behavior, 79(3), 401-411.
Schimpl, F. C., da Silva, J. F., de Carvalho Gonçalves, J. F., & Mazzafera, P. (2013). Guarana: revisiting a highly caffeinated plant from the Amazon. Journal of ethnopharmacology, 150(1), 14-31.
Silvestrini, G. I., Marino, F., & Cosentino, M. (2013). Effects of a commercial product containing guaraná on psychological well-being, anxiety and mood: a single-blind, placebo-controlled study in healthy subjects. Journal of negative results in biomedicine, 12(1), 9.
H. Fukumasu, J.L. Avanzo, M.K. Nagamine, J.A. Barbuto, K.V. Rao, and M.L.Z. Dagli. (2008). Paullinia cupana Mart var. sorbilis, guaraná, reduces cell proliferation and increases apoptosis of B16/F10 melanoma lung metastases in mice. Brazilian Journal of Medical and Biological Research. Vol. 41: 305-310