Persistence of anticancer activity in berry extracts after simulated gastrointestinal digestion and colonic fermentation

Fruit and vegetable consumption is associated at the population level with a protective effect against colorectal cancer. Phenolic compounds, especially abundant in berries, are of interest due to their putative anticancer activity. After consumption, however, phenolic compounds are subject to digestive conditions within the gastrointestinal tract that alter their structures and potentially their function. However, the majority of phenolic compounds are not efficiently absorbed in the small intestine and a substantial portion pass into the colon. We characterized berry extracts (raspberries, strawberries, blackcurrants) produced by in vitro-simulated upper intestinal tract digestion and subsequent fecal fermentation. These extracts and selected individual colonic metabolites were then evaluated for their putative anticancer activities using in vitro models of colorectal cancer, representing the key stages of initiation, promotion and invasion. Over a physiologically-relevant dose range (0–50 µg/ml gallic acid equivalents), the digested and fermented extracts demonstrated significant anti-genotoxic, anti-mutagenic and anti-invasive activity on colonocytes. This work indicates that phenolic compounds from berries undergo considerable structural modifications during their passage through the gastrointestinal tract but their breakdown products and metabolites retain biological activity and can modulate cellular processes associated with colon cancer

Flavonoids in tropical citrus species

HPLC with PDA and MS2 detection was used to identify and quantify flavonoids in the tropical citrus species Citrus microcarpa, Citrus hystrix, Citrus medica var. 1 and 2, and Citrus suhuiensis. Most of these species contained high amounts of flavones, flavanones, and dihydrochalcone C- and/or O-glycosides, which were identified on the basis of HPLC retention times, cochromatography with available authentic standards, absorbance spectra, and mass spectral fragmentation patterns. Among the major compounds detected were apigenin-6,8-di-C-glucoside, apigenin-8-C-glucosyl-2″-O-rhamnoside, phloretin-3′,5′-di-C-glucoside, diosmetin-7-O-rutinoside, hesperetin-7-O-neohesperidoside, and hesperetin-7-O-rutinoside. Most of the dihydrochalcone and flavone C-glycosides have not previously been detected in tropical citrus. C. microcarpa contained a high amount of phloretin-3′,5′-di-C-glucoside. Most of the tropical citrus flavanones were neohesperidoside conjugates, which are responsible for imparting a bitter taste to the fruit. Only C. suhuiensis fruit contains rutinoside, a nonbitte

Green tea flavan-3-ols: colonic degradation and urinary excretion of catabolites by humans

Following the ingestion of green tea, substantial quantities of flavan-3-ols pass from the small to the large intestine (Stalmach et al. Mol. Nutr. Food Res. 2009, 53, S44−S53; Mol. Nutr. Food Res. 2009, doi: 10.1002/mnfr.200900194). To investigate the fate of the flavan-3-ols entering the large intestine, where they are subjected to the action of the colonic microflora, (−)-epicatechin, (−)-epigallocatechin, and (−)-epigallocatechin-3-O-gallate were incubated in vitro with fecal slurries and the production of phenolic acid catabolites was determined by GC-MS. In addition, urinary excretion of phenolic catabolites was investigated over a 24 h period after ingestion of either green tea or water by healthy volunteers with a functioning colon. The green tea was also fed to ileostomists, and 0−24 h urinary excretion of phenolic acid catabolites was monitored. Pathways are proposed for the degradation of green tea flavan-3-ols in the colon and further catabolism of phenolic compounds passing into the circulatory system from the large intestine, prior to urinary excretion in quantities corresponding to ca. 40% of intake compared with ca. 8% absorption of flavan-3-ol methyl, glucuronide, and sulfate metabolites in the small intestine. The data obtained point to the importance of the colonic microflora in the overall bioavailability and potential bioactivity of dietary flavonoids

A novel approach for rapid micropropagation of maspine pineapple (Ananas comosus L.) shoots using liquid shake culture system

Maspine (Ananas comosus L.) is currently the most preferred pineapple variety in Malaysia due to its pleasant aroma and applicability in caning. Large quantities of plant materials are needed to fulfill the market demand which could not be obtained from the conventional breeding method. Hence, in vitro procedure was developed as an alternative method to improve the multiplication rate of this special variety. Sterilized explants were cultured on solidified Murashige and Skoog (MS) medium supplemented with various combinations of 6-benzylaminopurine (BAP) (1 to 5 mg/l) and ∝-naphthaleneacetic acid (NAA) (1 to 5 mg/l) hormones. Pineapple plant cultures required 5 mg/l BAP to significantly increase the shoot development during the in vitro stage. In addition, explants were subsequently sub-cultured on medium with 1 mg/l BAP which produced highest number of proliferated in vitro plantlets. The optimization of the conditions for shoot propagation was carried out in both liquid and solid medium by supplementing with 1 or 5 mg/l of BAP. MS liquid medium supplemented with 1 mg/l BAP produced the highest number of shoots (31) after 4 weeks. The number of shoots formed was increased to 204 after third sub-culture in liquid medium. Shoot proliferation was increased up to nine-fold in liquid medium when compared to the cultures maintained on solid medium. This improved method of Maspine in vitro multiplication will serve as an alternative source of planting materials of this cultivar for subsistence and large-scale pineapple farmers.Key words: Pineapple, in vitro, 6-benzylaminopurine, ∝-naphthaleneacetic acid, liquid medium

Bioavailability of <i>c</i>-linked dihydrochalcone and flavanone glucosides in humans following ingestion of unfermented and fermented rooibos teas

High-performance liquid chromatography-mass spectrometry (HPLC-MS&lt;sp&gt;n&lt;/sp&gt;) detected aspalathin and nothofagin, &lt;i&gt;C&lt;/i&gt;-glycosides of apigenin and luteolin, and four eriodictyol-&lt;i&gt;C&lt;/i&gt;-glycoside isomers in unfermented and fermented rooibos teas. The fermented drink contained 10-fold higher levels of aspalathin and nothofagin and a 4-fold lower eriodictyol-&lt;i&gt;C&lt;/i&gt;-glycoside content than the fermented tea. The total flavonoid contents in 500 mL servings of the teas were 84 (fermented) and 159 &#181;mol (unfermented). Following the ingestion of 500 mL of the teas by 10 volunteers, 0-24 h urine and plasma samples were collected for analysis. HPLC-MS&lt;sp&gt;n&lt;/sp&gt; identified eight metabolites in urine. These were &lt;i&gt;O&lt;/i&gt;-linked methyl, sulfate, and glucuronide metabolites of aspalathin and an eriodictyol-&lt;i&gt;O&lt;/i&gt;-sulfate. The main compound excreted was an O-methyl-aspalathin-O-glucuronide (229 &#181;mol) following ingestion of the unfermented drink and eriodictyol-&lt;i&gt;O&lt;/i&gt;-sulfate (68 &#181;mol) after ingestion of the fermented beverage. The overall metabolite levels excreted were 82 and 352 &#181;mol, accounting for 0.09 and 0.22% of the flavonoids in the fermented and unfermented drinks, respectively. Most of the aspalathin metabolites were excreted within 5 h of tea consumption, suggesting absorption in the small intestine. Urinary excretion of the eriodictyol-&lt;i&gt;O&lt;/i&gt;-sulfate occurred mainly during the 5-12 h collection period, indicative of absorption in the large intestine. Despite exhaustive searches, no flavonoid metabolites were detected in plasm

Synthesis, analytical features, and biological relevance of 5-(3′,4′-Dihydroxyphenyl)-γ-valerolactone, a microbial metabolite derived from the catabolism of dietary flavan-3-ols

The physiological significance of 5-(3′,4′-dihydroxyphenyl)- γ-valerolactone, an important metabolite derived from the catabolism of flavan-3-ols by gut microbiota, has been often overlooked due to the lack of the commercial standard. In the present work, this metabolite has been chemically synthesized, and its analytical parameters and antioxidant capacity have been determined in comparison to other chemical analogues [isomer 3-(3′,4′-dihydroxyphenyl)-δ-valerolactone and γ-valerolactone] and other structurally related compounds [(+)-catechin, (-)-epicatechin, and 3-(3,4-dihydroxyphenyl)-propionic acid]. The synthesized compound was also used to perform a targeted analysis in samples collected during the in vitro fermentation of a grape seed flavan-3-ol extract with human fecal microbiota from three healthy volunteers. The time-course formation of 5-(3′,4′-dihydroxyphenyl)-γ-valerolactone revealed large interindividual differences among volunteers, with concentrations ranging from 3.31 to 77.54 μM at 10 h of fermentation. These results are further discussed in view of the scarce reports quantifying 5-(3′,4′-dihydroxyphenyl) -γ-valerolactone in in vitro fermentation studies, and pharmacokinetic and intervention studies. © 2011 American Chemical Society.Peer Reviewe