Research on the Acai Berry

Summary

Human studies on the Acai berry or Acai extracts have been limited, so no firm statements can be made regarding the clinical benefits of this plant. Acai has, however, been eaten for thousands of years and its health benefits are legendary. There are many thousands of positive testimonials, albeit anecdotal. Research studies have been carried out in animals and cell culture systems.

Related article: The Amazing Acai Berry

Clinical study on antioxidant properties of Acai juice

This study assessed the in vitro and in vivo antioxidant properties of a juice blend (JB), MonaVie Active, containing a mixture of fruits and berries with known antioxidant activity, including Acai, a palm fruit, as the predominant ingredient. The phytochemical antioxidants in the JB are primarily in the form of anthocyanins, predominantly cyanidin 3-rutoside, cyanidin 3-diglycoside, and cyanidin 3-glucoside. The ‘cell-based antioxidant protection of erythrocytes (CAP-e)’ assay demonstrated that antioxidants in the JB penetrated and protected cells from oxidative damage ( p < 0.001). A randomized, double-blinded, placebo-controlled, crossover trial with 12 healthy subjects examined the JB’s antioxidant activity in vivo. Blood samples at baseline, 1 h, and 2 h following consumption of the JB or placebo were tested for antioxidant capacity using several antioxidant assays and the TBARS assay, a measure of lipid peroxidation. Subject taking JB showed an increase in serum antioxidants at 1 h ( p < 0.03) and 2 h ( p < 0.015), as well as inhibition of lipid peroxidation at 2 h ( p < 0.01) postconsumption [Jensen GS, Wu X, Patterson KM, Barnes J, Carter SG, Scherwitz L, Beaman R, Endres JR, Schauss AG. In vitro and in vivo antioxidant and anti-inflammatory capacities of an antioxidant-rich fruit and berry juice blend. Results of a pilot and randomized, double-blinded, placebo-controlled, crossover study. J Agric Food Chem. 2008 Sep 24;56(18):8326-33. Epub 2008 Aug 22].

Human pharmacokinetics of Acai pulp and juice

This study was carried out as an acute four-way crossover clinical trial with acai pulp and clarified acai juice compared to applesauce and a non-antioxidant beverage as controls. Healthy volunteers (12) were dosed at 7 mL/kg of body weight after a washout phase and overnight fast, and plasma was repeatedly sampled over 12 h and urine over 24 h after consumption. Pharmacokinetic analysis of total anthocyanins quantified as cyanidin-3-O-glucoside showed Cmax values of 2321 and 1138 ng/L at t max times of 2.2 and 2.0 h, and AUC last values of 8568 and 3314 ng h L(-1) for pulp and juice, respectively. Plasma antioxidant capacity was significantly increased by the acai pulp and applesauce. Individual increases in plasma antioxidant capacity of up to 2.3- and 3-fold for Acai juice and pulp, respectively were observed. The antioxidant capacity in urine, generation of reactive oxygen species, and uric acid concentrations in plasma were not significantly altered by the treatments. Results demonstrate the absorption and antioxidant effects of anthocyanins in Acai in plasma in an acute human consumption trial [Mertens-Talcott SU, Rios J, Jilma-Stohlawetz P, Pacheco-Palencia LA, Meibohm B, Talcott ST, Derendorf H. Pharmacokinetics of anthocyanins and antioxidant effects after the consumption of anthocyanin-rich acai juice and pulp (Euterpe oleracea Mart.) in human healthy volunteers. J Agric Food Chem. 2008 Sep 10;56(17):7796-802. Epub 2008 Aug 12].

Antioxidant properties of the Acai berry

The antioxidant properties of 11 commercial and non-commercial samples of Euterpe oleracea Mart. (Acai) fruit pulp were evaluated using the ‘total oxidant scavenging capacity assay’ against three reactive oxygen species [Lichtenthaler R, Rodrigues RB, Maia JG, Papagiannopoulos M, Fabricius H, Marx F. Total oxidant scavenging capacities of Euterpe oleracea Mart. (Acai) fruits. Int J Food Sci Nutr. 2005 Feb; 56(1): 53-64].

The antioxidant potential of all purple Acai samples was found to be excellent against peroxyl radicals, good against peroxynitrite, but poor against hydroxyl radicals relative to common European fruit and vegetable juices.

The phenolic compounds in purple Acai fruit pulp were identified by high-performance liquid chromatography-mass spectrometry. The two major anthocyanins, cyanidin-3-glucoside and cyanidin-3-rutinoside, were assayed using high-performance liquid chromatography-visible spectrometry. The contributions of the anthocyanins to the overall antioxidant capacities of the fruit were estimated to be only around 10%. Compounds not yet identified are responsible for the major part of the antioxidant capacities of Acai fruit pulp.

ORAC value of the Acai berry

The Acai berry has a high oxygen radical absorbance capacity (ORAC). Measurements of ORAC on freeze-dried Acai pulp and skin powder samples have been undertaken for 4 reactive oxygen species (ROS); superoxide, peroxynitrite, hydroxyl radicals and peroxyl radicals for both hydrophilic- and lipid-soluble species. The assay for superoxide gave a value of 161,400 units per 100 g, the highest yet found for any plant evaluated to date. The total ORAC value against peroxyl radicals, determined from both hydrophilic and lipophilic sources, was 102,700 units per 100 g, again the highest value found to date [Schauss AG, Wu X, Prior RL, Ou B, Huang D, Owens J, Agarwal A, Jensen GS, Hart AN, Shanbrom E. Antioxidant capacity and other bioactivities of the freeze-dried amazonian palm berry, Euterpe oleraceae mart. (Acai berry ). J Agric Food Chem. 2006 Nov 1;54(22):8604-10].

Phytochemical and nutrient composition of the Acai berry

In this study, a standardized freeze-dried Acai fruit pulp/skin powder was used for all analyses and tests. Anthocyanins (ACNs), proanthocyanidins (PACs), and other flavonoids were found to be the major phytochemicals. Two ACNs, cyandin 3-glucoside and cyanidin 3-rutinoside were the predominant ACNs; there were 3 other minor ACNs. The total content of ACNs was measured as 3.1919 mg/g dry weight (DW). Polymers were found to be the major PACs. The concentration of total PACs was calculated as 12.89 mg/g DW. Other flavonoids, namely, homoorientin, orientin, isovitexin, scoparin, and taxifolin deoxyhexose, along with several unknown flavonoids, were also assayed. Resveratrol was detected at a very low concentration. In addition, components including fatty acids, amino acids, sterols, minerals, and other nutrients were present. Total polyunsaturated fatty acid, total monounsaturated fatty acid, and total saturated fatty acids contributed to 11.1%, 60.2%, and 28.7% of total fatty acid, respectively. Oleic acid (53.9%) and palmitic acid (26.7%) were found to be the two dominant fatty acids. Nineteen amino acids were detected; the total amino acid content was measured at 7.59% of total weight. Sterols accounted for 0.048% by weight of the Acai powder. The three sterols B-sitosterol, campesterol, and sigmasterol were detected. A complete nutrient analysis is also presented [Schauss AG, Wu X, Prior RL, Ou B, Patel D, Huang D, Kababick JP. Phytochemical and nutrient composition of the freeze-dried amazonian palm berry, Euterpe oleraceae mart. (acai). J Agric Food Chem. 2006 Nov 1;54(22):8598-603].

Vasodilator properties of the Acai berry

The Acai berry is rich in polyphenols. Animal studies have been carried out to determine whether a hydro-alcoholic extract obtained from the berry can stimulate a vasodilator effect. The study (in the rat mesenteric vascular bed), carried out at the Department of Pharmacology and Psychobiology in Rio de Janeiro, Brazil, demonstrated that the vasodilator effect of the Acai extract was dependent on activation of the nitric oxide -cGMP pathway. It may also involve endothelium-derived hyperpolarizing factor release.

This vasodilator property of Acai berry extract suggests that the plant could have potential in the treatment of cardiovascular diseases [Rocha AP, Carvalho LC, Sousa MA, Madeira SV, Sousa PJ, Tano T, Schini-Kerth VB, Resende AC, Soares de Moura R. Endothelium-dependent vasodilator effect of Euterpe oleracea Mart. (Acai) extracts in mesenteric vascular bed of the rat. Vascul Pharmacol. 2006 Sep 1].

Anticancer effects of the Acai berry

Published in the Journal of Agricultural and Food Chemistry, a study demonstrated that extracts from the Acai berry triggered a self-destruct response in up to 86 percent of leukemia cells evaluated [Del Pozo-Insfran D, Percival SS, Talcott ST. 2006. Acai (Euterpe oleracea Mart.) polyphenolics in their glycoside and aglycone forms induce apoptosis of HL-60 leukemia cells. J Agric Food Chem. 2006 Feb 22; 54(4): 1222-9].

This was only a petri dish cell-culture model study and not a clinical trial. The findings are, however, encouraging. Other fruits, including grapes, guavas and mangoes, contain antioxidants shown to kill cancer cells in similar studies. Researchers are uncertain as to how effective antioxidants are against cancer cells in the human body, because factors such as nutrient absorption, metabolism and the influence of other biochemical processes may affect the antioxidants’ anticancer activity.

In the study, six different chemical extracts were made from acai fruit pulp, and each extract was prepared in seven concentrations. Four of the extracts were demonstrated to kill significant numbers of leukemia cells when applied for 24 hours. Depending on the extract and concentration, 35 percent to 86 percent of the cells died.

Increased consumption of fruits and vegetables is associated with decreased risk for many diseases, including heart disease and cancer. Consuming at least five servings a day of these nutrients is a good approach for helping promote optimal health.