Tumor cell proliferation and cyclooxygenase enzyme inhibitory compounds in Amaranthus tricolor

Amaranthus tricolor is consumed as a vegetable in Asia. Bioassay-directed isolation of leaves and stems of A. tricolor yielded three galactosyl diacylglycerols (1-3) with potent cyclooxygenase and human tumor cell growth inhibitory activities. The purified compounds were characterized by spectroscopic methods. In addition, the fatty acid moieties in diacyl galactosyl glyerols were characterized by GC-MS analyses. The galactosyl diacylglycerols 1-3 inhibited the cyclooxygenase-1 (COX-1) enzyme by 78, 63, and 93% and the cyclooxygenase-2 (COX-2) enzyme by 87, 74, and 95%, respectively. These compounds were tested for antiproliferative activity using human AGS (gastric), CNS (central nervous system; SF-268), HCT-116 (colon), NCI-H460 (lung), and MCF-7 (breast) cancer cell lines. Compound 1 inhibited the growth of AGS, SF-268, HCT-116, NCI-H460, and MCF-7 tumor cell lines with IC50 values of 49.1, 71.8, 42.8, 62.5, and 39.2 mug/mL, respectively. For AGS, HCT-116, and MCF-7 tumor cell lines, the IC50 values of compounds 2 and 3 were 74.3, 71.3, and 58.7 microg/mL and 83.4, 73.1, and 85.4, respectively. This is the first report of the COX enzyme inhibitory activity for galactosyl glycerols and antiproliferative activities against human colon, breast, lung, stomach, and CNS tumor cell lines.     

Impact of alkyl esters of caffeic and ferulic acids on tumor cell proliferation, cyclooxygenase enzyme, and lipid peroxidation

The antioxidant ferulic and caffeic acid phenolics are ubiquitous in plants and abundant in fruits and vegetables. We have synthesized a series of ferulic and caffeic acid esters and tested for tumor cell proliferation, cyclooxygenase enzymes (COX-1 and -2) and lipid peroxidation inhibitory activities in vitro. In the tumor cell proliferation assay, some of these esters showed excellent growth inhibition of colon cancer cells. Among the phenolics esters assayed, compounds 10 (C12-caffeate), 11 (C16-caffeate), 21 (C8-ferulate), and 23 (C12-ferulate) showed strong growth inhibition with IC50 values of 16.55, 13.46, 18.67, and 7.57 microg/mL in a breast cancer cell line; 9.65, 7.45, 17.05, and 4.35 microg/ mL in a lung cancer cell line; 5.78, 3.5, 4.29, and 2.46 microg/mL in a colon cancer cell line; 12.04, 12.21, 14.63, and 8.09 microg/ mL in a central nervous system cancer cell line; and 8.62, 7.76, 11.0, and 5.37 in a gastric cancer cell line. In COX enzyme inhibitory assays, ferulic and caffeic acid esters significantly inhibited both COX-1 and COX-2 enzymes. Caffeates 5-10 (C4-C12), inhibited COX-1 enzyme between 50% and 90% and COX-2 enzyme by about 70%, whereas ferulates 15-21 (C3-C8) inhibited COX-1 and COX-2 enzymes by 85-95% 25 microg/mL. Long-chain caffeates 11-14 (C16-C22) and short-chain ferulates 15-20 (C3-C5) were the most active in lipid peroxidation inhibition and showed 60-70% activity at 5 microg/mL concentration.     

Consumption of lycopene inhibits the growth and progression of colon cancer in a mouse xenograft model

A previous study indicated that lycopene could significantly inhibit the proliferation of human colon cancer cells in vitro. However, the in vivo anticancer effects of lycopene against colon cancer have not been demonstrated yet. Therefore, this study investigated whether consumption of lycopene could prevent the growth and progression of colorectal tumor in a mouse xenograft model. Bioluminescence imaging, histopathological, immunofluorescence (IFC), and immunohistochemical (IHC) staining results indicated that lycopene could effectively suppress the growth and progression of colon cancer in tumor-bearing mice. The results demonstrated that lycopene significantly suppressed the nuclear expression of PCNA and β-catenin proteins in tumor tissues. Consumption of lycopene could also augment the E-cadherin adherent molecule and nuclear levels of cell cycle inhibitor p21(CIP1/WAF1) protein. The chemopreventive effects of lycopene were associated with suppression of COX-2, PGE(2), and phosphorylated ERK1/2 proteins. Furthermore, the inhibitory effects of lycopene were inversely correlated with the plasma levels of matrix metalloproteinase 9 (MMP-9) in tumor-bearing mice. These results suggested that lycopene could act as a chemopreventive agent against the growth and progression of colorectal cancer in a mouse xenograft model.     

Tumor cell proliferation and cyclooxygenase inhibitory constituents in horseradish (Armoracia rusticana) and Wasabi (Wasabia japonica)

Cyclooxygenase and human tumor cell growth inhibitory extracts of horseradish (Armoracia rusticana) and wasabi (Wasabia japonica) rhizomes upon purification yielded active compounds 1-3 from horseradish and 4 and 5 from wasabi rhizomes. Spectroscopic analyses confirmed the identities of these active compounds as plastoquinone-9 (1), 6-O-acyl-beta-d-glucosyl-beta-sitosterol (2), 1,2-dilinolenoyl-3-galactosylglycerol (3), linolenoyloleoyl-3-beta-galactosylglycerol (4), and 1,2-dipalmitoyl-3-beta-galactosylglycerol (5). 3-Acyl-sitosterols, sinigrin, gluconasturtiin, and phosphatidylcholines isolated from horseradish and alpha-tocopherol and ubiquinone-10 from wasabi rhizomes isolated were inactive in our assays. At a concentration of 60 microg/mL, compounds 1 and 2 selectively inhibited COX-1 enzyme by 28 and 32%, respectively. Compounds 3, 4, and 5 gave 75, 42, and 47% inhibition of COX-1 enzyme, respectively, at a concentration of 250 microg/mL. In a dose response study, compound 3 inhibited the proliferation of colon cancer cells (HCT-116) by 21.9, 42.9, 51.2, and 68.4% and lung cancer cells (NCI-H460) by 30, 39, 44, and 71% at concentrations of 7.5, 15, 30, and 60 microg/mL, respectively. At a concentration of 60 microg/mL, compound 4 inhibited the growth of colon, lung, and stomach cancer cells by 28, 17, and 44%, respectively. This is the first report of the COX-1 enzyme and cancer cell growth inhibitory monogalactosyl diacylglycerides from wasabi and horseradish rhizomes.     

Optimizing sampling of tomato fruit for carotenoid content with application to assessing the impact of ripening disorders

Color defines one aspect of quality for tomato and tomato products. Carotenoid pigments are responsible for the red and orange colors of tomato fruit, and thus color is also of dietary interest. The aims of this study were (1) to determine the relative importance of field sampling and analytical replication when measuring lycopene and beta-carotene in tomato fruit and (2) to determine the effect of yellow shoulder disorder (YSD) on the content of lycopene and beta-carotene in tomato juice and tissue. Our results show that increasing biological replications is an efficient strategy for reducing the experimental error associated with measurements of lycopene and beta-carotene. Analytical replications did not contribute significantly to observed variation, and therefore experimental efficiency will be gained by reducing analytical replications while increasing field replication. We found that YSD significantly reduces lycopene in affected tissue and in juice made from affected fruit. In contrast, beta-carotene concentrations were only reduced in affected tissue but were not significantly reduced in juice. With increasing interest in biofortified crops, modulating the carotenoid profile in tomato by minimizing YSD symptoms represents a strategy for improving tomato fruit quality that is currently supported by grower contract structure and processor grades.     

Cultivars of apple fruits that are not marketed with potential for anthocyanin production

The red coloration of apple skin is mainly due to anthocyanins that are reported to possess health benefits. The aim of the present study was to determine the anthocyanin content in three underutilized Malus pumila Mill cultivars, Cranberry, Kerr, and Niedzwetzkyana, and confirm their anti-inflammatory and antioxidant activities. Our analysis revealed that the three cultivars studied contained primarily cyanidin-3-O-glucosyl rutinoside (1) at >99%. The anthocyanin was purified by C-18 medium pressure liquid chromatography and characterized by NMR spectral methods. The quantification of anthocyanins in M. pumila cultivars revealed that Cranberry, Kerr, and Niedzwetzkyana contained 1.12, 0.55, and 0.36 mg/g of fresh weight of 1, respectively. The lipid peroxidation (LPO) and cyclooxygenase enzyme (COX) inhibitory activities of 1 in water were compared with the activities of cyanidin-3-O-rutinoside (2) and cyanidin-3-O-glucoside (3) found in cherries and berries. There is a significant increase in LPO and COX enzyme-inhibitory activities of anthocyanin when tested in water compared to using dimethylsulfoxide as the carrier. The LPO inhibition of anthocyanins 1, 2, and 3 were 53.3, 68.3, and 87.9, respectively, at a 0.25 microM concentration. They inhibited the COX-1 enzyme by 42.7, 45.2, and 50.4 and COX-2 by 52.7, 61.5, and 68.5, respectively, at 5 microM. The LPO inhibitory values for commercial standards, BHA, BHT, and TBHQ, were 85, 89, and 94%, respectively at 1 microM. Similarly, positive controls aspirin, celecoxib, and robecoxib inhibited COX-1 and -2 enzymes by 68.6, 40.7, and 0% and 26.6, 72.2, and 92.4%, respectively, at 60, 26, and 32 nM.     

Cancer chemopreventive effects of lycopene: suppression of MMP-7 expression and cell invasion in human colon cancer cells

Clinical studies indicate that high blood levels of leptin or matrix metalloproteinase-7 (MMP-7; matrilysin) proteins are associated with tumor progression of human colorectal cancer (CRC). Leptin could play an important role in cell migration and invasion of cancer cells. Our previous study indicated that lycopene could inhibit the proliferation of human colon cancer cells in vitro. However, the inhibitory effects of lycopene on the progression of human colon cancer cells have not been demonstrated yet. In this study, we investigated the inhibitory effects of lycopene on tumor progression including cell invasion and MMP-7 expression in leptin-stimulated human colon cancer cells in vitro. Our results demonstrated that lycopene significantly inhibited leptin-mediated cell invasion and MMP-7 expression in human colon cancer HT-29 cells. Lycopene could augment the expression and stability of E-cadherin proteins. Our results showed that MAPK/ERK and PI3K/Akt signaling pathways played important roles in leptin-mediated MMP-7 expression and cell invasion. Lycopene could effectively inhibit the phosphorylation of Akt, glycogen synthase kinase-3β (GSK-3β) and ERK 1/2 proteins. The molecular mechanisms of lycopene were in part through decreases in nuclear levels of AP-1 and β-catenin proteins. These novel findings suggested that lycopene could act as a chemopreventive agent to suppress MMP-7 expression and leptin-mediated cell invasion in human colon cancer HT-29 cells.     

Color properties of four cyanidin-pyruvic acid adducts

Four anthocyanin-pyruvic adducts were synthesized through the reaction of cyanidin 3-O-glucoside, cyanidin 3-O-rutinoside, cyanidin 3-O-sophoroside, and cyanidin 3-O-sambubioside with pyruvic acid, structurally characterized by liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR), and their chromatic properties were studied (pH and SO2 stability assays). Overall, these pigments were shown to have a higher resistance to discoloration toward pH variations and also in the presence of SO2, being that this resistance to discoloration was explained by a higher protection of the chromophore group against the water or bisulfite nucleophilic attack that gives rise to the colorless hemiacetal form. Only slight differences in the protection against the nucleophilic attack of water and bisulfite were found to occur between all of the cyanidin-pyruvic acid adducts studied. Indeed, anthocyanin-pyruvic acid adducts with glucose or sambubiose attached to the 3-O position of the flavylium moiety were shown to have smaller bleaching constants compared with similar pigments that possess a rutinosyl or sophorosyl moiety. The study of the pigments (A-D and cyanidin-3-O-glucoside) color parameters, namely, chroma (C), lightness (L), and the hue angle (h(a,b)), obtained from the CIELAB system, revealed that different patterns of sugars in the anthocyanin-pyruvic acid adduct moiety affected the referred three parameters of color. The loss of saturation (DeltaC < 0) and the increase of lightness (DeltaL > 0) presented by the cyanidin-pyruvic acid adduct solutions at acidic pH values (1.0 and 2.0) showed that they are much less colored than the cyanidin-3-O-glucoside. For higher pH values (5.0 and 7.0), the reverse trend was observed. This means that the cyanidin-pyruvic acid adducts A-D are much more colored than the anthocyanin at these pH values. The higher coloring capacity of these pigments at higher pH values may be an important feature, indicating a putative application of these compounds in food products.     

Blackberry, black raspberry, blueberry, cranberry, red raspberry, and strawberry extracts inhibit growth and stimulate apoptosis of human cancer cells in vitro

Berry fruits are widely consumed in our diet and have attracted much attention due to their potential human health benefits. Berries contain a diverse range of phytochemicals with biological properties such as antioxidant, anticancer, anti-neurodegerative, and anti-inflammatory activities. In the current study, extracts of six popularly consumed berries--blackberry, black raspberry, blueberry, cranberry, red raspberry and strawberry--were evaluated for their phenolic constituents using high performance liquid chromatography with ultraviolet (HPLC-UV) and electrospray ionization mass spectrometry (LC-ESI-MS) detection. The major classes of berry phenolics were anthocyanins, flavonols, flavanols, ellagitannins, gallotannins, proanthocyanidins, and phenolic acids. The berry extracts were evaluated for their ability to inhibit the growth of human oral (KB, CAL-27), breast (MCF-7), colon (HT-29, HCT116), and prostate (LNCaP) tumor cell lines at concentrations ranging from 25 to 200 micro g/mL. With increasing concentration of berry extract, increasing inhibition of cell proliferation in all of the cell lines were observed, with different degrees of potency between cell lines. The berry extracts were also evaluated for their ability to stimulate apoptosis of the COX-2 expressing colon cancer cell line, HT-29. Black raspberry and strawberry extracts showed the most significant pro-apoptotic effects against this cell line. The data provided by the current study and from other laboratories warrants further investigation into the chemopreventive and chemotherapeutic effects of berries using in vivo models.     

1,2,3,4,6-penta-O-galloyl-β-D-glucose, quercetin, curcumin and lycopene induce cell-cycle arrest in MDA-MB-231 and BT474 cells through downregulation of Skp2 protein

The F-box protein S-phase kinase-associated protein 2 (Skp2), which acts as an oncogene through targeting p27 for degradation, is overexpressed in many different human cancers. Skp2 can play an important role in breast cancer progression and may also be a novel molecular target for the treatment of breast cancer, especially estrogen receptor (ER)/human epidermal growth factor 2 (HER2) negative breast cancers. Unfortunately, specific drugs that target Skp2 are unavailable at present. Therefore, it is important to explore whether commonly used chemopreventive agents may downregulate Skp2 expression. In this study, we examined the effects of 1,2,3,4,6-penta-O-galloyl-β-D-glucose (pentagalloylglucose, 5gg), quercetin, curcumin and lycopene on the expression of Skp2 in MDA-MB-231 (ER/HER2-negative) and BT474 (ER-negative/HER2-positive) cells. We found that all four phytochemicals studied induced cell growth inhibition in MDA-MB-231 cells. The mechanism of the initial growth inhibitory events involves blocking the cell cycle progression. Further, we found that quercetin and curcumin induced growth arrest by inhibition of Skp2, and induced p27 expression in MDA-MB-231 cells. However, the decrease in Skp2 levels in cells treated with 5gg or lycopene did not translate to p27 upregulation. Consequently, the downregulation of Skp2 did not always correlate with the upregulation of p27, suggesting that phytochemical-dependent downregulation of Skp2 can influence cell growth in several ways. Several studies have demonstrated that Skp2 directs the ubiquitylation and subsequent degradation of forkhead box protein O1 (FoxO1). Furthermore, our results reveal that FoxO1 protein was increased after 5gg, quercetin, curcumin and lycopene treatment. The therapeutic strategies designed to reduce Skp2 may therefore play an important clinical role in treatment of breast cancer cells, especially ER/HER2-negative breast cancers.     

Characterization of color fade during frozen storage of red grapefruit juice concentrates

Color changes in red grapefruit juice concentrates during storage at -23 degrees C for 12 months were studied. Concentrate (38 degrees Brix) was packed in both plastic (16 oz) and metal (6 oz) cans. Decrease in red intensity (CIE a) in juice color and slight increases in CIE L*, b*, and hue values from analysis of reconstituted juices were the characteristic color changes in concentrate during frozen storage. With respect to fresh concentrate, juice color in stored concentrate shifted toward the direction between negative DeltaC* and positive DeltaL*, indicating the color became slightly paler. A color difference seems to exist between the two containers, especially for the magnitude of DeltaE*; color changes were more pronounced in concentrates packed in plastic. There are significant changes (P < 0.05) in major carotenoid pigments (beta-carotene and lycopene) in the concentrates. More than 20% loss of lycopene and about 7% loss of beta-carotene occurred with plastic containers after a 12-month period. Regression analysis showed that the rate of decline was about 0.291 ppm per month (r = 0.990) for lycopene compared to 0.045 ppm (r = 0.817) for beta-carotene in concentrate stored in plastic. In the metal can, the same trends were observed but pigment losses were slightly smaller than those with plastic. An estimated shelf life for lycopene was 26.1 months in the metal can compared to 18 months in plastic. Shelf life for beta-carotene was more than 39 months, more than twice that of lycopene in plastic container.     

Identification of triterpene hydroxycinnamates with in vitro antitumor activity from whole cranberry fruit (Vaccinium macrocarpon)

Bioactivity-guided fractionation of cranberry fruit was used to determine the identity of triterpenoid esters from Vaccinium macrocarpon, which inhibit tumor cell growth and may play a role in cancer prevention. In our previous study, a fraction from whole fruit exhibited tumor cell growth inhibition in vitro. The major components of this fraction were isolated by chromatographic separation of ethyl acetate extracts, purified by semipreparative HPLC, and identified by NMR as cis- (1) and trans- (2) isomers of 3-O-p-hydroxycinnamoyl ursolic acid. These triterpenoid esters have not been previously reported in Vaccinium fruit. Bioassay of the purified triterpene cinnamates in tumor cell lines in vitro showed slightly greater activity of compound 1 in most cell lines, with GI(50) values of approximately 20 microM in MCF-7 breast, ME180 cervical and PC3 prostate tumor cell lines. Quercetin was slightly less active than 1, while cyanidin-3-galactoside exhibited much lower cytotoxicity, with GI(50) greater than 250 microM in all cell lines. Phenylboronic acid (3) was also isolated from the fruit but showed insignificant antitumor activity.     

Gene isolation, analysis of expression, and in vitro synthesis of glutathione S-transferase from orange fruit [Citrus sinensis L. (Osbeck)

Glutathione S-transferases (GSTs) (EC 2.5.1.18) are ubiquitous enzymes that have a defined role in xenobiotic detoxification, but a deeper knowledge of their function in endogenous metabolism is still lacking. In this work, we isolated the cDNAs as well as the genomic clones of orange GSTs. Having considered gene organization and homology data, we suggest that the isolated GST gene is probably involved in the vacuolar import of anthocyanins. We also found that the blood and blond orange GSTs shared the same nucleotide sequences, but as expected, the GST expression in the nonpigmented orange cultivar [Citrus sinensis L. (Osbeck)] (Navel and Ovale) was strongly reduced as compared to that of the pigmented orange (Tarocco). Interestingly, in the crude extracts of pigmented orange fruits, the GST activity was reproducibly detected by providing either 1-chloro-2,4 dinitrobenzene (CDNB) or cyanidin-3-O-glucoside (C-3-G) as substrates; moreover, we have shown that cyanidin-3-O-glucoside acted as a powerful competitive inhibitor of 1-chloro-2,4 dinitrobenzene conjugation to reduced glutathione (GSH) in the pigmented orange, confirming that this molecule might easily bind to the active site of the enzyme and functions as a putative substrate. In addition, we have reported here the successful in vitro expression of orange GST cDNAs leading to a GST enzyme that is active against cyanidin-3-O-glucoside, thus suggesting the probable involvement of the isolated gene in the tagging of anthocyanins for vacuolar import. This last result will help to study the kinetic and structural properties of orange fruit GST avoiding time-consuming protein purification procedures.     

Composition and thermal stability of anthocyanins from chinese purple corn ( Zea mays L.)

Chinese purple corn extracts ( Zea mays L., Zhuozhou, Hebei, China) (EZPC) were selected among five Chinese purple corn hybrids due to their higher anthocyanin content, and their thermal stability was evaluated. The total anthocyanin content and total phenolic content of EZPC were 304.5 +/- 16.32 mg of cyanidin-3-glucoside equiv/100 g of dry seeds and 489.8 +/- 24.90 mg of gallic acid equiv/100 g of dry seeds, respectively. Moreover, the individual anthocyanins of EZPC were determined by HPLC-DAD/ESI-MS analysis. Seven main compounds were determined, including cyanidin-3-(malonylglucoside), cyanidin-3-O-glucoside-2-malonylglucoside, cyanidin-3-O-glucoside, peonidin-3-O-glucoside, peonidin-3-(malonylglucoside), pelargonidin-3-(6'-malonylglucoside), and peonidin-3-(dimalonylglucoside). The thermal stability of EZPC was studied by differential scanning calorimetry. Thermodynamic analysis showed that the conversion of EZPC followed an Arrhenius relationship, where the delta enthalpy (H) and activation energy (E(a)) were 97.0 J/g and 204 +/- 2.72 kJ/mol, respectively. Furthermore, the relationships between the degree of conversion of EZPC and time or temperature were reported. This study demonstrated that the evaluated Chinese purple corn hybrids are a natural source of anthocyanins and are stable over a wide range of temperatures and times.     

UV-visible spectroscopic investigation of the 8,8-methylmethine catechin-malvidin 3-glucoside pigments in aqueous solution: structural transformations and molecular complexation with chlorogenic acid

The physicochemical properties of 8,8-methylmethine catechin-malvidin 3-O-glucoside isomers, commonly referred to as catechin-ethyl-malvidin 3-O-glucoside, have been studied in aqueous solutions and compared with those of the parent anthocyanin (malvidin 3-O-glucoside). The hydration and acidity constants (pKh and pKa) of the catechin-ethyl-malvidin 3-O-glucoside pigments and malvidin 3-O-glucoside were determined by UV-visible spectroscopic measurements. The ethyl-linked catechin-malvidin 3-O-glucoside pigments present higher stability toward hydration than the parent anthocyanin. The high resistance of these ethyl-linked pigments toward the hydration is related to the self-association that offers optimal protection from the nucleophilic attack of water. Moreover, the ethyl link may confer to the molecule enough flexibility to undergo intramolecular interaction, further protecting it from hydration and bisulfite discoloration. In the wine pH range (3.2-4.0), due to the low pKa and high pKh values, the ethyl-linked pigments are present as colored forms (flavylium cation and quinonoid bases).     

Carotenoid pigments in Rosa mosqueta hips, an alternative carotenoid source for foods

Carotenoid composition has been investigated in Rosa mosqueta hips (Rosa rubiginosa, Rosa eglanteria). Six major carotenoids were identified (beta-carotene, lycopene, rubixanthin, gazaniaxanthin, beta-cryptoxanthin, and zeaxanthin) together with other minor carotenoids (violaxanthin, antheraxanthin, and gamma-carotene). An average composition has been estimated as follows: beta-carotene (497.6 mg/kg of dry wt), lycopene (391.9 mg/kg of dry wt), rubixanthin (703.7 mg/kg of dry wt), gazaniaxanthin (289.2 mg/kg of dry wt), beta-cryptoxanthin (183.5 mg/kg of dry wt), zeaxanthin (266. 6 mg/kg of dry wt), and minor carotenoids (67.1 mg/kg of dry wt). Possible uses in food technology are outlined and discussed including the preparation of highly colored oleoresins as natural colorants of food and beverages and as provitamin A sources.     

Bioaccessibility of beta-carotene, lutein, and lycopene from fruits and vegetables

Epidemiological studies have consistently demonstrated that there is an association between carotenoid-rich food intakes with a low incidence in chronic diseases. Nevertheless, there is not an association between the intake of total dietary carotenoids and chronic health incidence in the European population, probably because of different carotenoid food sources and bioavailability. The objective of this study was to evaluate the small and large intestine bioaccessibilities of major dietary carotenoids from fruits and vegetables in a common diet. A bioaccessibility model that includes enzymatic digestion and in vitro colonic fermentation was employed. Lutein presented greater small intestine bioaccessibility (79%) than beta-carotene (27%) or lycopene (40%). With regard to large intestine bioaccessibility, similar amounts of lycopene and beta-carotene were released from the food matrix (57%), whereas small amounts of lutein (17%) were released. These results suggest that 91% of the beta-carotene, lutein, and lycopene contained in fruits and vegetables is available in the gut during the entire digestion process. Colonic fermentation is shown to be important for carotenoid availability in the gut.     

Assessment of degradation and intestinal cell uptake of carotenoids and chlorophyll derivatives from spinach puree using an in vitro digestion and Caco-2 human cell model

Although numerous studies have demonstrated the health benefits of chlorophyll derivatives, information regarding the digestion, absorption, and metabolism of these phytochemicals is quite limited. To better understand the digestion of these pigments, green vegetables including fresh spinach puree (FSP), heat- and acid-treated spinach puree (HASP), and ZnCl(2)-treated spinach puree (ZnSP) were subjected to an in vitro digestion method which simulates both the gastric and small intestinal phases of the process. Native chlorophylls were converted to Mg-free pheophytin derivatives during digestion. Conversely, Zn-pheophytins were completely stable during the digestive process. Transfer of lipophilic chlorophyll derivatives, as well as the carotenoids lutein and beta-carotene, into the aqueous micellar fraction from the food matrix was quantified. Micellarization of total chlorophyll derivatives differed significantly (p < 0.05) for FSP (37.6%), HASP (17.2%), and ZnSP (8.7%). Micellarization of chlorophyll a derivatives was determined to be significantly more efficient than chlorophyll b derivatives in FSP and HASP (p < 0.01), but not in ZnSP (p > 0.05). Intestinal cell uptake of micellarized pigments was investigated using HTB-37 (parent) and clonal TC7 lines of human Caco-2 cells. Medium containing the pigment-enriched fraction generated during digestion was added to the apical surface of fully differentiated monolayers for 4 h. Pigments were then extracted from cells and analyzed by C18 HPLC with photodiode array detection. Both Caco-2 HTB-37 and TC7 clone cells accumulated 20-40% and 5-10% of micellarized carotenoid and chlorophyll derivatives, respectively. These results are the first to demonstrate uptake of chlorophyll derivatives by human intestinal cells and to support the potential importance of chlorophylls as health-promoting phytochemicals.     

Stability and color changes of thermally treated betanin, phyllocactin, and hylocerenin solutions

Thermal degradation of betanin, phyllocactin (malonyl-betanin), and hylocerenin (3' '-hydroxy-3' '-methyl-glutaryl-betanin) solutions isolated from purple pitaya (Hylocereus polyrhizus [Weber] Britton and Rose) was monitored by spectrophotometric and high-performance liquid chromatography-diode array detection (HPLC-DAD) analyses. For betanin and phyllocactin solutions, the color shift upon thermal treatment was found to be nearly identical, while hylocerenin samples exhibited an intelligibly higher chromatic steadiness. Betanin proved to be the most stable individual pigment structure, while the enhanced tinctorial stability of the integral phyllocactin and especially hylocerenin solutions was due to the formation of red degradation products exhibiting improved color retention as opposed to their respective genuine pigments. Individual structure-related stability characteristics can exclusively be assessed by HPLC-DAD analyses and may not be noticed by mere spectrophotometric assessment of color and tinctorial strength.