INTRODUCTION

Camu-camu, is a fruit-bearing shrub or small tree in the myrtle family (Myrtaceae) that grows around semi- to fully-flooded areas from Brazil to Peru, particularly around ox-bow lakes where there is not much current.^1-3 In Brazil, its geographical distribution ranges from the Atlantic coast in the state of Pará through the states of Roraima, Amazonas, Rondônia, and to the border with Peru.⁴ It grows approximately 6-9 feet (2-3 meters) tall and has small white flowers. The plant produces green fruit 1 inch (2-3 cm) in diameter that turns reddish-purple as it ripens during flooding or high-water seasons.¹ The simple leaves are elongated with pointed tips and are from 1.5 to 4 inches (4-10 cm) long and 1 to 1.5 inches (2-4 cm) wide.² However, the variability in both leaf and fruit size can be much greater. For example, trees along the Putumayo River, an Amazon tributary which forms part of Colombia’s border with Ecuador, were found to have leaves more than 2.75 inches (7 cm) wide and 5.5 inches (14 cm) long and fruits over 2 inches (4 cm) in diameter.⁵

In Peru, 2 different species are referred to as camu-camu. “Camu-camu arbustivo” (Myrciaria dubia) is widely distributed in the state of Loreto in the river basins of the Nanay, Napo, Ucayali, Marañon, Tiger, Tapíche, Yarapa, Tahuayo, Pintuyacu, Itaya, Ampiyacu, Maniti, Oroza, Putumayo, Yavari, and Curaray. “Camu-camu arbóreo” (M. floribunda) occurs throughout the southern part of the Peruvian Amazon in the state of Ucayali.^3,6 For the purposes of this article, only M. dubia will be discussed.

HISTORY AND CULTURAL SIGNIFICANCE

Myrciaria dubia (syn: M. paraensis, Psidium dubium) has numerous common names in addition to camu-camu, including camo camo (Peru); araza de agua (Spanish); camu-camu negro (Peru); guapuro blanco (Bolivia); rumberry (English); cacari, azedinha, miraúba, or muraúba (Brazil); algracia, guayabillo blanco, guayabito, and limoncillo (Venezuela).^5,7

The fruit was first sold in Iquitos, Peru as one of a multitude of non-timber forest products (NTFPs) extracted from the wild, but until its promotion as an edible fruit in the 1970s, there was no significant international market for it as an NTFP.⁵ There is very little published folklore on camu-camu as an edible fruit.⁵ Rarely was the sour, acidic fruit eaten by the people of the rainforest and it has not been documented as a traditional herbal remedy for any condition in the Amazon region.¹ In Iquitos, the fruit recently has become popular in juice drinks, liqueurs, and ice cream.^1,3,8 Currently, in Peru, the juice is drunk straight or with water for flu, and stomach and intestinal conditions. Peruvians also make the bark into a poultice for wounds and take a bark decoction with fruit juice and rum for rheumatism.⁸ Some Peruvians used it as fish bait and as a source of high-quality firewood.⁴

When its high vitamin C content was discovered, researchers and product developers in countries around the world became interested in the plant.¹ The vitamin C concentration of fresh camu-camu fruit averages 2.4 to 3.0 grams of ascorbic acid per 100 g of fresh pulp, which is roughly 30 times that of an orange.^1,3,5,8,9 Additionally, it provides 10 times more iron, 3 times more niacin, twice as much riboflavin, and 50% more phosphorus than oranges.¹ The fruits also provide 711 mg/kg of potassium, or 18 mEq (milliequivalents) of potassium per kg; the daily recommended amount is about 2,000 mg per day, or 51 mEq.^1,10 Beta-carotene, calcium, and thiamin are also found in the fruit, as is the anthocyanin, cyanidin 3-glucoside, and delphinidin 3-glucoside.^11,12

Based on the vitamin C content, author and retired economic botanist, James A. Duke, PhD, suggests that the fruit may be used for aging, arthritis, asthma, cardioprotection, the common cold, Crohn’s disease, eczema, flu, glaucoma, high blood pressure, high cholesterol, obesity, osteoporosis, pain, and Parkinson’s, although research for most of these theoretical applications has not been conducted.⁸

CURRENT AUTHORIZED USES IN COSMETICS, FOODS, AND MEDICINES

In a February 2012 draft revision of the Codex Alimentarius Commission classification of foods and animal feeds, it is proposed that “Rumberry” (Myrciaria dubia (Kunth) McVaugh) be listed within commodity sub-group 005A “Assorted tropical and sub-tropical fruits – edible peel – small”.¹³ In the European Union (EU), camu-camu fruit and pulp are presently classified as “novel” foods with status “FS,” meaning “According to information available to Member States competent authorities this product was used only as or in food supplements (FS) before 15 May 1997. Any other food uses of this product have to be authorised pursuant to the Novel Food Regulation.”¹⁴ As such, the oral use of camu-camu in the EU presently is authorized only as a component of food supplement products,¹⁵ for example as a source of vitamin C.¹⁶ Through the World Trade Organization (WTO) process, the government of Peru is proposing that “traditional products” such as camu-camu that have a history of safe consumption in the country of origin and other parts of the world, barring the EU, be excluded from the scope of Regulation 258/97 of the European Parliament and of the Council concerning novel foods and novel food ingredients.¹⁷

Concerning the use of camu-camu in cosmetic products in the EU, the European Commission Health and Consumers Directorate lists both “Myrciaria Dubia Fruit Extract” and “Myrciaria Dubia Seed Extract” for use as a skin-conditioning (maintains the skin in good condition) ingredient. “Myrciaria Dubia Fruit Juice” (the juice expressed from the fruit) is listed for both antioxidant (inhibits reactions promoted by oxygen, thus avoiding oxidation and rancidity) and emollient (softens and smoothes the skin) functions.¹⁸

In North America, camu-camu is regulated as a component of notified dietary supplement products (source of vitamin C) in the United States.¹⁹ In Canada, camu-camu is regulated as a component of licensed Natural Health Products (NHPs), for example as a medicinal ingredient of complex mixtures. These mixtures include ones in combination with acerola fruit (Malpighia glabra, Malpighiaceae) concentrate, bromelain (from pineapple, Ananas comosus or A. bracteatus, Bromeliaceae), citrus bioflavonoids, rose hips (Rosa canina, Rosaceae), rutin, and vitamin C for approved use a “a factor in the normal development and maintenance of bones, cartilage, teeth and gums,”²⁰ or, for example, in combination with Spanish black radish root (Raphanus sativus var. niger; Brassicaceae), and acerola fruit for an approved use as “an antioxidant for the maintenance of good health. Helps the body to metabolize fats and proteins.”²¹ As a non-medicinal ingredient (NMI), “Myrciaria dubia fruit flavour” is approved for use as a flavor enhancer component of NHPs.²²

For the development of standards in Peru, a technical sub-committee for the standardization of camu-camu has been established within the membership of the Instituto Peruano de Productos Naturales (IPPN; Peruvian Institute of Natural Products).²³ In Brazil, a camu-camu research group was established in 1994 within the Instituto Nacional de Pesquisas da Amazônia (INPA; Brazilian National Institute of Amazonian Research). The research group, headed by Dr. Kaoru Yuyama, had over 20 scientific papers on camu-camu published in 2011 alone.²⁴

MODERN RESEARCH

While there is research looking at the ecology, cultivation, pests (insects and fungi), and more on M. dubia, particularly led by the Instituto de Investigaciones de la Amazona Peruana (IIAP), there is very little clinical research on the plant. In a 2008 study evaluating the anti-oxidative and anti-inflammatory effects of camu-camu for the prevention of atherosclerosis in humans, 20 male smoking volunteers without other risk factors were randomly assigned to take 70 mL of 100% camu-camu juice (1050 mg of vitamin C) or 1050 mg of vitamin C tablets for 7 days.¹² There was an overall significant decrease in oxidative stress markers (urinary 8-hydroxy-deoxyguanosine, p<0.01; and total reactive oxygen species, p<0.05) and inflammatory markers (high sensitivity C reactive protein, p<0.05; interleukin-6, p<0.05; and interleukin-8, p<0.01) in the group taking camu-camu juice but no change in the vitamin C group. The source of this marked decrease in overall inflammation is thought to be due to not only the high concentration of vitamin C in camu-camu fruit, but also other antioxidant/anti-inflammatory components and/or substances that help increase the rate of absorption of vitamin C.

In a 2002 study evaluating the effects of camu-camu fruit extract with açaí (Euterpe oleracea, Arecaceae) fruit juice as sources of vitamin C and iron in preschoolers with mild anemia, 85 children (2 to 6 years old of both sexes) were randomly divided into 5 groups to take (once daily with lunch) 150 mL açaí juice (standardized to 2 mg iron), or 150 mL açaí juice (2 mg iron) with camu-camu extract (40 mg vitamin C), or iron amino acid chelate 1 mg, or iron amino acid chelate 2 mg, or deionized water for 120 days.²⁵ Regardless of the source of iron, no significant differences in hemoglobin concentrations were observed, although there was a better recovery of anemic children in the 2 mg iron amino acid chelate group. Significant weight gain was observed in both the açaí and açaí plus camu-camu groups.

The remainder of the literature on camu-camu is based on animal and pharmacological studies and the potential human uses of the fruit are extrapolated from this research. While these investigations are useful, it is clear that further clinical research is needed to evaluate any proposed medicinal uses.

A 2010 in vitro study compared the presence of bioactive compounds and the antioxidant/antidiabetic potential of 16 native Brazilian fruits and found that camu-camu had the highest antioxidant capacity, including the highest total phenolic and ellagic acid content, but did not inhibit alpha-amylase or alpha-glucosidase as efficiently as some of the other fruits.²⁶ Thus, it may not be as beneficial for the control of postprandial hyperglycemia as some of the other fruits studied.

A 2010 chemical study evaluated the changes in antioxidant capacity and total phenolic contents of camu-camu fruit at different stages of maturity.²⁷ In addition to the vitamin C content, camu-camu possesses 30 phenolic compounds including flavan-3-ols (catechin and its derivatives), ellagic acid derivatives, anthocyanins (delphinidin 3-glucoside and cyanidin 3-glucoside), flavonols (rutin and its derivatives), and flavanones (naringenin and eriodictyol derivatives), of which flavan-3-ols and ellagic acid were the most common at all stages of maturity. The presence of hydrolyzed tannins (gallo- and ellagitannins) was also shown.

In 2005, a chemical analysis also found that the major anthocyanins in camu-camu were cyanidin-3-glucoside (89.5%) and delphinidin-3-glucoside (4.2-5.1%).²⁸ This study examined the fruit from 2 different regions in Brazil and found that the region with higher rainfall and lower temperatures produced fruit with higher overall anthocyanin contents.

A chemical study in 2000 aimed to characterize the volatile compounds in a number of Brazilian fruits, in order to pave the way for finding ways to retain high-quality aroma and flavor in product production.²⁹ In this study, 21 different volatile compounds were found in camu-camu fruit, the majority of which were terpenes (98%), specifically alpha-pinene (66%) and d-limonene (24%).

Another 2000 study investigated the vitamin C stability in stored camu-camu and found an overall 23% decrease in vitamin C content after 28 days of storage, which remained relatively stable, increasing to only a 26% loss at 335 days of storage.⁹ This represents a decrease in vitamin C from 2.4-3.0 g/100g of pulp to 1.57-1.21 g/100g of pulp.

FUTURE OUTLOOK

The principle forms of camu-camu exported from Peru are powder (73.40%), extract (10.44%), pulp (7.97%), dehydrated (4.72%), marmalade (1.72%), in capsules (1.13%), flour (0.01%), and other forms (0.61%). The reported customs value of camu-camu exports from Peru has declined significantly since 2007 with the 2011 export value (USD $922,103.56) at about one-fifth that of 2007 (USD $5,024,563.05). During the 13-year period of 1999 through 2011, calendar years 2006, 2007, and 2008 showed the highest export values for camu-camu.³⁰ The principle export markets for Peruvian camu-camu ingredients and products in 2008 were Japan (52.38%), the Netherlands (27.22%), United States (15.32%), Canada (2.96%), and other countries (2.12%).³¹

The camu-camu tree is an important component of riparian vegetation in Peru and Brazil, and is especially abundant in Peruvian black water systems, i.e., those rivers that have deep, slow-moving channels that flow through forested wetlands and swamps.⁵ Although wild populations of the tree are highly productive, with some studies estimating fruit production at 9,000 to 12,000 kg per hectare in wild populations, interest in maximizing economic returns has led to cultivation of the tree as a way to increase rural incomes and raise standards of living. In 1996, the Peruvian government promoted and funded “reforestation” projects of camu-camu on the floodplains of the Peruvian Amazon as a flood-resistant and potentially highly productive tree crop. By 2006, only 10% of fields planted for these projects were planted on sites on which mature forests had been removed, but it is possible that more extensive clearing of mature forests could occur as camu-camu becomes more widely cultivated.⁵ This planting program has had mixed success. There has been a lack of technical support on how to care for the plant and many have not survived. Also, some of these new orchard systems are on higher ground and no longer as flooded, leading to an increase in pest problems (M. Martin, personal communication March 20, 2012). In Peru, about 10,000 families are involved in camu-camu cultivation with Ucayali State as the focal production area and secondarily Loreto State, a conservation area due to the presence of natural tree stands and small-scale plantations. Started in 1997, the Agro-exportation Program project for camu-camu cultivation was projected to include 5,000 hectares of camu-camu by 2010, with 2,500 distributed in the Ucayali region and 2,500 in Loreto, including natural groves.³²

One study comparing the differences between the wild and cultivated trees found variability in morphology and phenology.⁵ The wild trees usually fruit once per year, but cultivated camu-camu appears to be less seasonal, and flowers and fruits at all stages of development can be found on a single tree, with trees frequently experiencing 2 fruiting cycles within a 6-month period. However, farmers cultivating the trees were concerned that the yields from the planted stock were not as high as from wild trees. Based on the variations in phenology (season and climactic effects on plants) and morphology of cultivated trees, there is also concern that the vitamin C content from the fruit of these trees may not be as substantial as from those in the wild, although there are no published reports of analysis of vitamin C levels to substantiate this concern.⁵

Now that widespread commercialization is taking place, a better understanding of the genetic variation is necessary to improve the productivity and vitamin C content of the cultivated tree. In addition, national and international market development will help local populations capitalize on farming of the fruit and its products.¹⁰ In addition to more work on the cultivation of the fruit, there continues to be high potential for sustainable management of the wild stands. These wild areas still have huge amounts of production, and in fact are showing even higher densities of camu-camu plants per area. Thus, the fruit as an important NTFP should not be overlooked. In fact, much of the fruit continues to come from wild stands, although a shift to the more reliable cultivated plants is beginning to emerge (M. Martin, personal communication March 20, 2012).

—Gayle Engels and Josef Brinckmann

REFERENCES

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