History and Origin
Acai is the fruit of Euterpe oleraceae Martuis, a large palm tree indigenous to Central and South America. These tall and slender tree grow mainly in swamps and floodplains. The palm's fruit, which is dark purple in color and grows in berry-like clusters, have formed an important food source in this part of the world. Traditionally, various parts of the plant have been used in folk medicines by native peoples, with the berries used to make a variety of beverages and used medicinally to treat diarrhea. 1,2
Owing to its antioxidant capacity,3 acai berry is now a popular dietary supplement commonly sold in the form of juices, sweetened fruit pulps and smoothies.4 Acai is exported to Asia, Europe and North America.1 It is one of the 20 top selling botanical dietary supplement sourced through natural and healthfood stores in US, where sales of the herbal supplement have shown a sharp increase in recent years.5
Components and Activities
Free radicals and reactive oxygen species which are formed both as a by-product of normal metabolism and through harmful environmental factors such as pollution and sun damage, have the potential to damage various important molecules in the body, including proteins, lipids, and DNA. This process is described as oxidative stress.6
Acai has attracted a great deal of attention because of its potent antioxidant activity, which is thought to arise mainly from its flavonoid, anthocyanin and proanthocyanidin contents. Antioxidants such as these help defend the body against free radicals and oxidative stress, thereby slowing down the associated damaging effects that, left unchecked, can lead to signs of photoaging.6,7
Five anthocyanins have been identified in acai, of which cyanidin 3-glucoside and cyanidin 3-rutinoside are the predominant compounds.2 Interestingly, the total anthocyanin content in freeze-dried acai has been measured at 3.19 mg/g, which is markedly lower than that seen in most other dark-colored berries, such as blackberries, cranberries or blueberries.2
Flavonoids are a group of antioxidant phytochemicals that are widely distributed in fruits and vegetables and are considered particularly beneficial because they inhibit oxidation via multiple biological pathways.6 Twelve flavonoid compounds have been detected in acai, including homoorientin, orientin, taxifolin deoxyhexose, isovitexin, and scoparin.2 In addition proanthocyanidins, a group of polyphenolic compounds, are present in acai. Polyphenolic compounds, as a group, are considered the most potent antioxidants found in nature and are probably the largest group of phytochemicals to have demonstrated preventing effects.6 The proanthocyanidin profile in acai is similar to that seen in blueberries2 a widely publicized "superfood."
Acai also contains lignan compounds with potent hydroxyl radical scavanging activity and, in some cases, cytoprotective effects against hydrogen peroxide.1
In addition to its antioxidant content, acai is rich in essential fatty acids, predominantly in oleic acid (56.2%), palmitic acid (24.1%), linoleic acid (12.5%). Total unsaturated fatty acids forms nearly three quarters of the fatty acid content in acai.2
The table below summarizes results from a number of in vitro studies that examined the neutralizing activity if freeze-dried acai against various free radicals that are found in the body, including hydroxyl and superoxide.8-10 As can be seen, acai displays potent antioxident activity relative to other fruits and vegetables.9
Table. Performance of freeze-dried açai fruit pulp/skin powder in antioxidant assays8-10 [Schauss et al.2006b](Table 1, p.8608) [Wu et al 2004] (table 1, p.4029 and table 2, p.4030)[Ou et al. 2002](Fig 4, p.2775)
|Antioxidant Assay||target Free Radical||Result||Comment|
|Hydrophilic ORACFL||Peroxyl||997 µmol TE/g||Substantially higher than that of most dark-colored berries or any other fruits and vegetables|
|Lipophilic ORACFL||Peroxyl||30 µmol TE/g||Higher than that of other berries|
|HORAC||hydroxyl||52 µmol GAE/g||Similar to that of grapes|
|NORAC||Peroxynitrite||34 µmol TE/g||Average compared with other fruits|
|SOD||Superoxide||1614 units/g||Extremely high compared with other fruits and vegetables|
ORACFL= oxygen radical absorbance capacity with fluorescein as the fluorescent probe:
HORAC= hydroxyl radical averting capacity;NORAC= peroxynitrite radical averting capacity
SOD= Superoxide scavenging assay
Other potential bioactivities of acai include both anti irritant properties and a mild inhibitory effect on cyclooxygenase-1 and cyclooxygenase-2.8
Potential Skincare Application
The skin is exposed to endogenous and environmental oxidative stress, resulting in the generation of free radicals that in turn produce skin damage. Oxidative damage to the skin may menifest as photoaging.7 Free radicals, such as superoxide anion and peroxyl and hydroxyl radicals, cause the most damage because they are short lived and extremely chemically reactive causing cellular damage at the site where they are made.11 The skin is rich in antioxidants to neutralize reactive oxygen species when they form, but the environmental assault (from pollutant sunlight, and smoking) can overwhelm the endogenous antioxidant system, resulting in the accumulation of damage and tissue aging.11 Exogenous antioxidants applied to the skin can help augment the skin's natural defenses and limit this damage.11
To date, scientific data published on the potential benefits of acai have focused on its in vitro radical scavenging activities.8 However, considering its high oxygen radical absorbance capacity, it is likely acai offers great potential as a component in skin care products. The potential anti-irritant effects of acai' may also translate into benefits to individuals with sensitive skin.
Safety & Tolerability
For individuals with pollen allergies or a known hypersensitivity to similar berries, it may be wise to avoid this fruit.
- Chin Y-W, Chai H-B, Keller WJ. Kinghorn AD. Lignans and other constituents of the fruits of
Euterpe oleracea (Acai) with antioxidant and cytoprotective activities. J Agric Food Chem. 2008:56(17):7759-7764.
- Schauss AG, WU X, Prior RL, et al. Phytochemical and nutrient composition of the freez-dried Amazonian palm perry. Euterpe oleraceae Mart. (Acai). J Agric Food Chem. 2006a;54(22):8598-8603.
- Baumann L Woolery-Lloyd H, Friedman A. 'Natural ingredients' in cosmetic dermatology. J Drugs Dermatol 2009; 8(6 Supplement): s5-S9
- Mertens-Taloott SU, Rios J, Jilma-Stchlawetz F, el al. Pharmacokinetics of anthocyanins and antioxidant effects after consumption of anthocyanin-rich ar..a: juice and pulp (Euterpe- oleracea Mart) in human nee/thy valun-,eers. .1 Agric Food Chem. 2008;56(17):7796-7802.
- Cavaliere C, Rea P, Lynch ME, Blumenthal M. Herbal supplement sales experience slight increase in 2008. HerbalGram. 2009;82:58-61 American Botanical Council. Available at http://cms.herbalgram.org/herbalgram/issue82/ article3400.html. Accessed 26 April, 2010.
- Tsao R, Akhtar MH. Nutraceuticals and functional foods: I. Current trend in phytochemical antioxidant research. J Food Agric Environment. 2005;3(1):10-17.
- Berson DS. Natural antioxidants. J Drugs Dermato1. 2008;7(7 supply)s7-s12.
- Schauss AG, Wu X. Fhior RL, et al. Antioxidant capacity and other bioactivities of the freeze-dried Amazonian palm berry, Euterpe oleraceae Mart. (Acai). J Agric Food Chem. 2006b:54(22):8604-8610.
- Wu X. Beecher GR. Holden J, Haytowitz DB, Gebhardt SE, Prior R L. Lipophilic and hydrophilic antioxidant capacities of common foods in the United States. J Agric Food Chem. 2004:52(12):4028-4037.
- Ou B. Hampsch-Woodill M. Flanagan J. Deemer EK, Prior RL. Huang D. Novel fluormetric assay for hydroxyl radical prevention capacity using fluorescein as the probe. J Agric Fooc Chem. 2002;5D(10):2772-2777.
- Pinnel SR. Cutaneous photodamage, oxidative stress, and topical antioxidant protection. J Am Acad Dermatol. 2003;48(1):1-19.