Search

Cherry juice from one cultivar was fermented for 0, 24, 48, and 72 h using Lactobacillus acidophilus, and its effects related to management of hyperglycemia, hypertension, inhibition of Helicobacter pylori, and proliferation of probiotic Bifidobacterium longum were evaluated using in vitro models. Cherry extract was fermented by initially adjusting the pH to 6.0 and at the natural acidic pH. Analysis was carried out by adjusting the pH and at fermented acidic pH at each time point from each of the two samples. Total soluble phenolics decreased over a period of 72 h for initial pH adjusted samples whereas it increased or remained constant for natural acidic pH samples. DPPH linked antioxidant activity and α-glucosidase inhibitory activity decreased for samples where final pH was adjusted whereas it increased for natural acidic pH samples. Fermentation led to a decrease in hypertension-relevant ACE inhibitory activity for all samples. Natural acidic pH samples had Helicobacter pylori inhibitory activity at ...

Ulcer-associated dyspepsia is caused by infection with Helicobacter pylori which is linked to the majority of peptic ulcers. Antibiotic treatment does not always inhibit or kill H. pylori with potential for antibiotic resistance. The objective of this study was to determine the potential of lactic acid bacterial fermented milk and soymilk products to inhibit H. pylori. All fermented product extracts had inhibitory potential, except for Lactobacillus bulgaricus fermented soymilk sample. Further, the addition of cranberry–chitosan oligosaccharide mixture to the fermented substrates did not inhibit the growth of Lactobacillus plantarum (LP2) but further enhanced H. pylori inhibition. The observed H. pylori inhibition was correlated to the increased total phenolic content in the fermented extracts due to cranberry phenolics. These results confirm the potential of lactic acid bacterial fermented milk and soymilk products to inhibit H. pylori. When combined with cranberry phenolics and prebiotic chitosan oligos...

The health-relevant functional benefits of Lactobacillus bulgaricus and Lactobacillus acidophilus fermented milk and soymilk were investigated and targeted for management of hyperglycemia and related complication of hypertension using in vitro models. Free radical scavenging-linked antioxidant activity and enzyme inhibitory activities linked to hyperglycemia (α – amylase and α−glucosidase) and hypertension (angiotensin – I converting enzyme, ACE) of fermented substrates were evaluated using in vitro assays. These activities were correlated to phenolic and lactic acid contents. In spite of total phenolic content decreasing over 24 h, the free radical scavenging-linked antioxidant activity increased. α−Glucosidase inhibitory activity increased with fermentation, with higher activity in soymilk substrate. α–Amylase inhibitory activity was high in milk substrate throughout the fermentation and in soymilk it increased from a lower initial activity. Initial ACE inhibitory activity was high in soymilk and was ma...

Staphylococcus aureus, a Gram-positive organism, is responsible for numerous infections ranging in severity from skin and soft tissue infections to endocarditis and septic arthritis. Further, Staphylococcal food poisoning (SFP) caused by enterotoxigenic staphylococci is one of the main food-borne diseases. In this study, several single-seed origin clonal lines of herbs from Lamiaceae family were screened for antimicrobial applications against S. aureus. These clonal lines have consistent total phenolic content, phenolic profile and antioxidant activity as opposed to heterogenous phenolic profiles of typical herbal extracts. The clonal extracts of specific herb species were evaluated for anti- S. aureus activity. Water extracts of clonal lemon balm had the highest anti- S. aureus activity followed by clonal extracts of rosemary RoLA, sage, oregano, rosemary Ro-6, rosemary RoK-2 and chocolate mint. The anti- S. aureus activity of the water extracts correlated with gallic acid and caffeic acid content, which...

Natural α-amylase and α-glucosidase inhibitors from food-grade plants offer an attractive strategy to manage of postprandial hyperglycemia for Type II diabetes. Inhibition of Angiotensin I-Converting Enzyme (ACE) is also considered useful as a therapeutic approach in the treatment of high blood pressure, one of the long-term complications of diabetes. In the current study, we evaluated the inhibitory activity of phenolic extracts produced during Kefir culture-mediated fermentation of soymilk supplemented with Rhodiola extracts against α-amylase, α-glucosidase and angiotensin converting enzyme (ACE). We also investigated phenolic-linked antioxidant activity and content of salidroside and tyrosol with fermentation time. α-Glucosidase inhibitory activity increased moderately with fermentation after 24 h and correlated to increased tyrosol and reduced salidroside contents. α-Amylase inhibitory activity decreased to zero with fermentation time, and the initial high activity prior to fermentation strongly corre...

Listeria monocytogenes is one of the most severe food-borne bacterial infections causing Listeriosis. As L. monocytogenes can survive harsh adverse conditions – such as low pH, high NaCl, and refrigeration temperatures – as well as resist current antimicrobial measures such as the use of disinfectants and antibiotics, there is a need for alternative anti-Listeria strategies. In the search for new antimicrobial agents, much recent research has focused on the potential of dietary phenolic compounds. In this study, soybean extracts enriched for phenolic content via dark-germination sprouting or solid-state bioprocessing by the dietary fungus Rhizopus oligosporus or Lentinus edodes were investigated for in vitro antibacterial activity against L. monocytogenes. L. monocytogenes growth was inhibited most effectively by R. oligosporus bioprocessed soybean extracts, which showed anti-Listeria activity at total phenolic concentrations as low as 10 µg 100 µL−1. In both sprouted soybean extract and L. edodes-bioproc...

Cranberry pomace modified by solid-state bioprocessing with the food-grade fungi Rhizopus oligosporus and Lentinus edodes was investigated for antimicrobial effects against Helicobacter pylori. The results indicated that solid-state bioprocessing enriched the cranberry pomace with phenolic antioxidants and important phenolic phytochemicals such as ellagic acid. The antimicrobial activity of the extracts against H. pyloriwas also enriched by solid-state bioprocessing. Further, the results also indicated that the antimicrobial activity correlated strongly with total soluble phenolic content and ellagic acid, suggesting different modes of antimicrobial function. A dose-dependent analysis of antimicrobial activity suggested that there could be a possible synergistic mode of interaction between the phenolic phytochemicals. Solid-state bioprocessing of cranberry pomace using the food-grade fungi R. oligosporus and L. edodes could therefore be an innovative approach to develop antimicrobial ingredients for dieta...

Soybean isoflavonoids and related phenolic antioxidants from other dietary plant species have long been associated with numerous biological activities linked to the chemoprevention of cancers and oxidation-linked diseases. But until now, no mechanisms or models have been put forth to explain how all of these activities of dietary phenolics could work together to promote health and protect from disease. Here, we present a hypothetical model based on the soybean isoflavonoid genistein for the beneficial action of dietary phenolic antioxidants that incorporates not only the known molecular activities, but also the known metabolic effects that dietary phenolics have on cellular systems such as energy metabolism and the antioxidant enzyme response to reactive oxygen species. Our model presents in a clear manner how a cancerous cell, although mutated and dysfunctional on both biochemical and genetic levels, cannot escape its beginnings as a normal cell and the underlying response mechanisms that are re...

Helicobacter pylori infection has been implicated as a major cause of gastric inflammation, peptic ulcer disease, and gastric cancer. While antibiotics have been the mainstay of current therapies for gastrointestinal disease linked to H. pylori infection, negative side-effects and antibiotic resistance issues have strengthened the need for alternative therapeutic strategies. In the search for new antimicrobial agents, much recent research has focused on the potential of dietary phenolic compounds. In this study, soybean extracts enriched for phenolic content via sprouting or solid-state bioprocessing by the dietary fungus Rhizopus oligosporus were investigated for in vitro antibacterial activity against H. pylori. Helicobacter pylori growth inhibition by soybean extracts was increased most effectively by 2 d sprouting or 2 d R. oligosporus bioprocessing. Anti-H. pylori activity was not associated with antioxidant activity, but was linked to extracts when activity of the phenolic-polymerizing enzy...

Food safety continues to be a major concern for the food industry in recent years. One of the industry's top priorities has been to find alternative ways to preserve their newly developed foods while satisfying the increasing consumer demand to produce safe, all-natural products. In order to achieve this “clean label”, much research has been devoted to the use of effective plant-based antimicrobials, such as those from herbs and spices, to replace chemical preservatives. However, due to the cross-pollination character of herbs and spices, there is a lot of genetic heterogeneity among different batches of the same plant species. This poses a problem for the routine use of plants, and their extracts, as a barrier towards microbial growth. In order to combat this, a unique tissue-culture-based selection strategy was used to isolate an elite phenolic phytochemical-producing clonal line of oregano (Origanum vulgare). Ethanol extracts of this elite clonal line of oregano were then used to study its inhibitory a...

We are applying a dynamic systems biology approach to the development of several phenolic phytochemicals in food-grade plants as ingredients for functional food applications. Phenolic antioxidant phytochemicals from food-grade plants will be an important part of a healthy diet in a global population that is projected to reach 9 billion in the next 50 years. Such phytochemicals are being targeted for designing conventional foods with added health benefits (functional foods). Such value-added foods are needed for dietary support to manage major oxidation-linked diseases, such as diabetes, cardiovascular disease, arthritis, cognition diseases and cancer. Plants produce phenolic metabolites as a part of growth, developmental and stress-adaptation response. These stress and developmental-modulated phenolic phytochemicals can be targeted for the design of functional foods. In order to design consistent food-grade phytochemical profiles for safety and clinical relevancy, novel tissue culture and bioprocessing te...

Previous research has suggested a relationship between free phenolic content and β-glucosidase activity in solid-state fermented food substrates and to amylase activity in germinating soybeans. This study was undertaken to examine the role of a number of carbohydrate-cleaving enzymes in phenolic antioxidant mobilization from whole soybean during solid-state fermentation. In addition to total soluble phenolic content, α- and β-glucosidase, α-amylase, and β-glucuronidase activities were measured in extracts of soybean fermented with a food-grade fungus, Rhizopus oligosporus. Antioxidant activity of the extracts was determined as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability. Our results demonstrate that while total soluble phenolic content increased 120–135% in the extracts, increased antioxidant activity (+61%) was limited to the early fermentation period, with activity decreasing with increased culture time. Higher antioxidant activity was linked to increased glucosidase and glucuronidas...

Foods that contain plant phenolic secondary metabolites that are antioxidants are getting more attention due to an increase in experimental data suggesting health-promoting effects when such foods are ingested as part of a low-fat diet. As the synthesis of phenolic compounds in plants is known to increase during the defense response to microorganisms, we investigated specific food-grade microbial polysaccharides as potential elicitors of mungbean phenolic content. Mungbean (Vigna radiata) was pretreated with solutions of both xanthan and gellan gums, as well as commercial yeast extract and purified yeast glucan (as potential fungal elicitors), and dark-germinated for 1–5 days. Tissue samples were assayed for enzymatic (glucose-6-phosphate dehydrogenase and guaiacol peroxidase) and antioxidant activity, and for proline and phenolic content. Microbial polysaccharide treatments were found to stimulate phenolic content and enzyme activity, as well as occasional cotyledon pigmentation. In addition, xa...

Cranberry pomace is a byproduct of the cranberry processing industry that can be targeted for production of value-added phenolic ingredients. Bio-processing of pomace by solid state fermentation (SSF) using food grade fungi provides unique strategies to improve nutraceutical properties and to produce functional phenolic ingredients. Several functional phenolic phytochemicals exist as glycosides or as other conjugated forms with reduced biological activity. We hypothesize that during SSF the fungal glycosidases mobilize some phenolic antioxidants in cranberry pomace and their activity by hydrolysis via β-glucosidase and releasing the aglycone. To develop this strategy we used food grade fungus Rhizopus oligosporus. Our goal was to target the release of simple phenolic aglycones and mobilized diphenyls. SSF of cranberry pomace was done for 16 days with nitrogen sources, ammonium nitrate (NH4NO3) and fish protein hydrolysate (FPH). The two nitrogen treatments increased water extractable phenolics by...

Fava beans are important legumes of the Mediterranean diets that potentially contain higher total phenolics and associated antioxidant activity compared to many other legumes. Further, fava beans with high L-dihydroxy phenylalanine (L-DOPA) are known to have anti-Parkinson's effect. In this study, we investigated the stimulation of L-DOPA, total phenolics and related antioxidant activity in dark germinated seeds by food grade elicitors, gellan gum, a polysaccharide from Pseudomonas elodea and xanthangum from Xanthomonas campestris. The objective of this study was to investigate the role of glucose-6-phosphate dehydrogenase (G6PDH), the first rate-limiting enzyme of the pentose phosphate pathway leading to the synthesis of phenolic acid, L-DOPA and the activity of guaiacol peroxidase (GPX). We also investigated the potential link between proline metabolism and G6PDH activity in dark germinated fava bean over a period of 8 days. Total phenolics, L-DOPA, proline and antioxidant activity were determined. L-DO...

Previous research in our lab investigated the stimulatory effects of phenolic elicitors on plant seed development and the production of phenolics for lignification and nutraceutically relevant antioxidants. Metabolic flux of metabolites through the pentose-phosphate pathway towards eventual lignin formation might be driven by regulated activity of the rate-limiting enzyme glucose-6-phosphate dehydrogenase (G6PDH) in response to phenolic-scavenging peroxidase activity. Through regulated activity of such enzymes, the metabolism for plant recovery and defense may be optimized under stressful conditions. As of yet, no direct correlation between stress-inducing treatments in plant cultures and possible stimulatory effects on purified enzymes involved inlignification and phenolic antioxidant pathways (specifically, peroxidases) has been reported. In order to investigate our hypothesis of an elicitor-induced stimulatory effect on peroxidase activity, we studied partially-purified guaiacol peroxidase (GPX) enzyme...

Acetyl salicylic acid (ASA) and fish protein hydrolysate (FPH) were investigated for stimulating valuable phenolics production in transformed anise root cultures (Pimpinella anisum L.) for food and nutraceutical applications. Anise root cultures were grown in Murashige‐Skoog (MS) hormone free medium. Total phenolics in anise root cultures decreased with ASA and ASA/FPH treatments and may possibly be diverted to lignification as indicated by increase in guaiacol peroxidase (GPX) activity. Epoxy‐pseudoisoeugenol‐(2‐methylbutyrate) (EPB) production in root cultures in response to FPH treatment increased 3 fold compared to control and 6 fold higher compared to ASA treatment on day 60. The optimum concentration of FPH for EPB stimulation was 2 ml/L of standardized mackerel hydrolysates and if the concentration was higher than 2 ml/L, FPH was inhibitory to growth of root cultures. Antioxidant activity in all treatments was high on day 60 compared to day 30. On either day, there was no difference in ant...

Rosmarinic acid (RA) and related phenolics are natural antioxidants found as secondary metabolites in spearmint (Mentha spicata). These phenolic‐secondary metabolites have diverse food processing and nutraceutical applications. Since natural cross‐pollination results in plant to plant variation in the level of phenolic metabolites, tissue culture‐based techniques are essential to isolate elite antioxidant‐producing clonal lines. The objective of this research is to develop tissue culture‐based selection techniques to isolate high rosmarinic acid and phenolic‐producing clonal lines from a heterogenous bulk seed population of spearmint. Multiplied clonal shoots of each line were screened for tolerance to azetidine‐2‐carboxylate (A2C). Individual shoot apex of each line were also screened for Pseudomonas tolerance. Rosmarinic acid and total phenolics were assayed in all treated clonal lines and compared to uninoculated/untreated shoot expiants of corresponding line. The Pseudomonas and A2C treatment...

We have established three clonal lines of oregano (Origanum vulgare) for the purpose of investigating the possible link between de novo synthesis of proline and the phenylpropanoid pathway. We used Pseudomonas as inoculation in the otherwise sterile micropropagated oregano shoots to stimulate a defense response. Oregano clones, like other plants, carry out an elicitor‐mediated defense response by inducing the phenylpropanoid pathway. Free phenolics and rosmarinic acid are produced via this pathway. We measured free proline, rosmarinic acid, and free phenolics in oregano shoots. We found that the induced higher levels of rosmarinic acid in some Pseudomonas inoculated clones and at several stages is often correlated to higher levels of proline in those same clones. We found no conclusive link between free phenolics and free proline levels. From this study clonal line 0–4 appeared to be the best line to investigate the role of proline‐linked pentose phospahte pathway in regulating rosmarinic acid sy...

Elite oregano clonal lines are being targeted by our laboratory for food preservative and nutraceutical applications. Oregano (Origanum vulgare) shoot clones inoculated with Pseudomonas sp. resulted in increased phenolics, reduced hyperhydricity, better tolerance to environmental stress and better adaptability when compared to uninoculated control. In order to confirm the qualitative and biochemical observations related to potential lignification and cellulose build up, we have conducted mechanical load deformation analysis using a TEXTURE ANALYZER (extensometer) instrument after killing the shoots in boiling methanol and thereby removing the internal turgor pressure, instead of directly quantifying the lignin content by chemical methods. Protocol in this study was different in that we have used peak force upon rupture, breaking strain, deformability modulus and toughness parameters as the key criteria for demonstrating whether Pseudomonas ‐ induced unhyperhydrated shoots were stronger than the c...

Rosmarinic acid is a natural antioxidant and is found as a secondary metabolite in rosemary (Rosmarinus officinalis). It is of interest in food preservation due to its antioxidant and antimicrobial activities. Previously maintained shoot‐based clonal line of rosemary designated as R‐l (based on RA content, total phenolics content, tolerance to Pseudomonas sp and RA stimulation) was used in this study to compare RA biosynthesis in shoot vs callus cultures. Callus cultures were generated from shoot cultures of R‐l line following transformation with Agrobacterium rhizogenes‐containing a natural plasmid that alters plant development. The shoot and transformed callus cultures of R‐l were isolated and maintained separately on hormone free Murashige and Skoog medium (MS/HF). The effect of light and dark conditions on callus growth and RA production was investigated. RA biosynthesis in shoot cultures was also compared due to its relevance to greenhouse production and organ culture. We found that callus m...

Melon (Cucumis melo L.) is an important fruit crop cultivated widely in every region of the world. Our laboratory is targeting this species for production of novel proteins important to food industry. Prior to expression of protein of interest in transgenic melon an efficient genetic transformation system has to be developed. In this context we are testing a wide variety of promoters fused to reporter gene for β‐glucuronidase (GUS) for expression specifically in melon fruits. In this study in melon, salicylic acid‐inducible promoter region of pathogenesis‐related protein gene (PR1a) of tobacco fused to β‐glucuronidase (GUS) gene was introduced into melon via Agrobacterium‐mediated gene transfer using a binary vector system. Gene transfer was effective when Agrobacterium virulence factors like acetosyringone (100 μM) and low pH (5.2) were provided during the co‐culture step. Transformed shoots were recovered from benzyladenine‐induced cut cotyledons using kanamycin gene as a selective marker. Rege...

Phenolic metabolites from oregano and related species in the family Lamiaceae are important sources of antimicrobials and antioxidants. The content of phenolic metabolites in oregano and related species are highly variable due to genetic heterogeneity. This genetic heterogeneity is due to the breeding character being influenced by natural cross‐pollination. In order to develop gene pools to improve ingredient quality and quantity genetically uniform shoot‐based clonal lines were isolated using plant tissue culture techniques. Clonal lines were generated from multiple shoots induced by 1 mg/1 benzylaminopurine in standard Murashige and Skoog medium with 3 % sucrose. Under these optimum conditions 7–10 shoots per explant were generated for further clonal propagation or regeneration of plants. Shoot‐inducing hormones like thidiazuron and adenine sulfate did not improve multiple shoot‐forming ability. Individual shoots of several individual clonal lines with each originating from a single heterozygou...