Isolation and Identification of Strawberry Phenolics with Antioxidant and Human Cancer Cell Antiproliferative Properties

Center for Human Nutrition, David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA.
Journal of Agricultural and Food Chemistry (Impact Factor: 2.91). 03/2008; 56(3):670-5. DOI: 10.1021/jf071989c
Source: PubMed


Studies suggest that consumption of berry fruits, including strawberries ( Fragaria x ananassa Duch.), may have beneficial effects against oxidative stress mediated diseases such as cancer. Berries contain multiple phenolic compounds, which are thought to contribute to their biological properties. Comprehensive profiling of phenolics from strawberries was previously reported using high-performance liquid chromatography with mass spectrometry (HPLC-MS) detection. The current study reports the isolation and structural characterization of 10 phenolic compounds from strawberry extracts using a combination of Amberlite XAD16-resin and C18 columns, HPLC-UV, and nuclear magnetic resonance (NMR) spectroscopy methods. The phenolics were cyanidin-3-glucoside ( 1), pelargonidin (2), pelargonidin-3-glucoside (3), pelargonidin-3-rutinoside (4), kaempferol (5), quercetin (6), kaempferol-3-(6'-coumaroyl)glucoside) (7), 3,4,5-trihydroxyphenyl-acrylic acid (8), glucose ester of ( E)- p-coumaric acid (9), and ellagic acid . Strawberry crude extracts and purified compounds 1- 10 were evaluated for antioxidant and human cancer cell antiproliferative activities by the Trolox equivalent antioxidant capacity (TEAC) and luminescent ATP cell viability assays, respectively. Among the pure compounds, the anthocyanins 1 (7156 microM Trolox/mg), 2 (4922 microM Trolox/mg), and 4 (5514 microM Trolox/mg) were the most potent antioxidants. Crude extracts (250 microg/mL) and pure compounds (100 microg/mL) inhibited the growth of human oral (CAL-27, KB), colon (HT29, HCT-116), and prostate (LNCaP, DU145) cancer cells with different sensitivities observed between cell lines. This study adds to the growing body of data supporting the bioactivities of berry fruit phenolics and their potential impact on human health.

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Available from: David Heber, Dec 18, 2014
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    • "These metabolites showed the highest and statistically significant differences (p<0.05) between UGT71W2 silenced and pBI-intron control fruit. By comparison of their MS and retention times with those of authentic references, compound 6 was identified as kaempferol-3-(6'-coumaroyl) glucoside (a product of kaempferol 3-glucoside) as a decreased metabolite in UGT71W2-RNAi line (Zhang et al. 2008). These data confirmed that UGT71W2 could contribute to the glucosylation of kaempferol in vivo. "
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    ABSTRACT: Glycosylation determines the complexity and diversity of plant natural products. To characterize fruit ripening-related UDP-dependent glycosyltransferases (UGTs) functionally in strawberry, we mined the publicly available Fragaria vesca genome sequence and found 199 putative UGT genes. Candidate UGTs whose expression levels were strongly up-regulated during fruit ripening were cloned from F.×ananassa and six were successfully expressed in Escherichia coli and biochemically characterized. UGT75T1 showed very strict substrate specificity and glucosylated only galangin out of 33 compounds. The other recombinant enzymes exhibited broad substrate tolerance, accepting numerous flavonoids, hydroxycoumarins, naphthols and the plant hormone, (+)-S-abscisic acid (ABA). UGT71W2 showed the highest activity towards 1-naphthol, while UGT71A33, UGT71A34a/b and UGT71A35 preferred 3-hydroxycoumarin and formed 3- and 7-O-glucosides as well as a diglucoside from flavonols. Screening of a strawberry physiological aglycone library identified kaempferol, quercetin, ABA and three unknown natural compounds as putative in planta substrates of UGT71A33, UGT71A34a and UGT71W2. Metabolite analyses of RNA interference (RNAi)-mediated silenced fruits demonstrated that UGT71W2 contributes to the glycosylation of flavonols, xenobiotics and, to a minor extent, of ABA, in planta. The study showed that both specialist and generalist UGTs were expressed during strawberry fruit ripening and the latter were probably not restricted to only one function in plants.
    Full-text · Article · Oct 2015 · Plant and Cell Physiology
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    • "The fruit quality of strawberries is primarily determined by chemical qualities such as soluble sugars, organic acids, and antioxidants. The functional ingredients of strawberry fruits are represented by many secondary metabolites, such as anthocyanins, flavonoids, and phenolic compounds, which are presumed to be used defensively to prevent harmful damage caused by reactive oxygen species (Gil et al., 1997; Zhang et al., 2008; Zheng et al., 2007). Environmental factors such as light, water, CO 2 , temperature, and nutrients are important elements in the production of highquality strawberries (Cantliffe et al., 2007; Sun et al., 2012). "
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    ABSTRACT: This study was aimed at investigating the production of phytochemicals that determine fruit quality, and evaluating growth characteristics of mature strawberry plants during cultivation under three different wavelengths (blue, red and blue plus red) of LED light. Cultivation was conducted in two separate locations, namely, a growth chamber (GC) illuminated with LED lights as the sole light source and a plastic greenhouse (PG) which was given supplemental LED light in addition to ambient light. It was noted that leaves of plants cultivated in the GC under LED lights displayed elevated levels of chlorophyll compared with those cultivated in the PG. In contrast, plants cultivated in the PG with supplementary LED lights yielded much higher production of fruits than those cultivated in the GC. Moreover, fruits harvested in the PG were demonstrated to contain higher levels of organic acids than those harvested in the GC. When the effects of different LED lights were examined, a remarkably higher production of fruits was achieved in the PG when ambient light was supplemented with either blue LED light or combined blue and red LED light. Furthermore, it was also noted that greater accumulation of organic acids and phytochemicals such as phenolic compounds were observed in the fruits that had been cultivated in the PG when ambient light was supplemented with either red LED light or combined blue and red LED lights.
    Full-text · Article · Jun 2015 · Scientia Horticulturae
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    • "Finally, the health's benefits promoted by the consumption of fruits and vegetables are not explained by the action of a single compound or molecule. The phytochemical mixture contained in plants could work simultaneously to exert health benefits in a collaborative way (Seeram et al., 2004; Zhang et al., 2008). In the next section we will discuss research advances in the health-benefits effects of food anthocyanins in diabetes, obesity, cardio-vascular disease and cancer prevention, neuronal and visual improvement. "
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    ABSTRACT: Anthocyanins are one of the most abundant flavonoid compounds. These pigments, naturally present in fruits and vegetables, provide color and promote health benefits to consumers due to their antioxidant capacity. To date, more than 600 anthocyanins have been identified in nature, all coming from six anthocyanidin aglycones derived from flavylium backbone with different glycosylations and acylations. The different anthocyanin conjugates absorb light at about 500 nm and are responsible for the red, blue and purple color of fruits and vegetables. Many studies in cell lines, animal models and human clinical trials suggest that anthocyanins have anti- carcinogenic and anti- inflammatory activities, provides cardiovascular disease prevention, promote obesity and diabetes control benefits, and also improve visual and brain functions. Those health benefits are mainly associated with their antioxidant effects, which clearly are influenced by the molecular mechanism related to the expression and modulation of key genes. The bioavailability of anthocyanins in functional foods is one of the questions to solve regarding their putative health-promoting effects... Is there any correlation between food sources with more anthocyanins content and their higher health benefits? What is the best source of anthocyanins to obtain the highest health-promoting properties? These are questions covered in the present article.
    Full-text · Chapter · Dec 2014
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