Kalidas Shetty

Inhibition of Helicobacter pylori and associated urease by oregano and cranberry phytochemical synergies.

ABSTRACT Ulcer-associated dyspepsia is caused by infection with Helicobacter pylori. H. pylori is linked to a 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 for using phenolic phytochemical extracts to inhibit H. pylori in a laboratory medium. Our approach involved the development of a specific phenolic profile with optimization of different ratios of extract mixtures from oregano and cranberry. Subsequently, antimicrobial activity and antimicrobial-linked urease inhibition ability were evaluated. The results indicated that the antimicrobial activity was greater in extract mixtures than in individual extracts of each species. The results also indicate that the synergistic contribution of oregano and cranberry phenolics may be more important for inhibition than any species-specific phenolic concentration. Further, based on plate assay, the likely mode of action may be through urease inhibition and disruption of energy production by inhibition of proline dehydrogenase at the plasma membrane.

Solid state production of polygalacturonase by Lentinus edodes using fruit processing wastes

Fruit-processing wastes including apple pomace, cranberry pomace and strawberry pomace were used as substrates for polygalacturonase (PG) production by Lentinus edodes through solid-state fermentation. Strawberry pomace was the best substrate for highest PG yield, followed by apple pomace, while cranberry pomace was not a suitable substrate for PG production in this study. The highest PG activity was obtained after 40 days of culture and the yields from strawberry pomace, apple pomace and cranberry pomace were 29.4 U, 20.1 U and 14.0 U per gram of pomace, respectively. PG activity was increased by the addition of polygalacturonic acid in the apple pomace and cranberry pomace media, but was not affected in strawberry pomace medium. The PG produced by L. edodes from strawberry pomace exhibited a maximal activity at 50°C and at pH 5. The enzyme was fairly stable up to 50°C and between pH 3.0 and 6.5. The acid tolerant property of the enzyme made it suitable for applications in most fruit and vegetable processing industries. This value-added bioconversion strategy may be applicable for the utilization of other food processing wastes.

Enhancement of pea (Pisum sativum) seedling vigour and associated phenolic content by extracts of apple pomace fermented with Trichoderma spp.

Abstract We previously reported that three apple pomace-based Trichoderma inoculants enhanced seedling vigour in pea ( Pisum sativum ) germinated in potting soil. The objective of this study was to further investigate the effect of isolated extracts from these bioinoculants on phenolic content and seedling vigour in peas. When pea seeds were pre-treated with Trichoderma viride , Trichoderma harzianum and Trichoderma pseudokoningii inoculant extracts, the germination rate in potting soil increased by, 15, 15 and 20%, respectively, compared with water treatment control. After 5 days of growth, the average plant height increased by 27, 39 and 31%, respectively; the average fresh weight increased by 33, 46 and 36%, respectively. The average phenolic content, another key indicator of vigour identified in our studies, increased by 13, 18 and 17%, respectively. The root elongation during germination of pre-treated pea seeds was more rapid than control. Pea seeds treated for 24 h with the dilution of 10 −2 of Trichoderma inoculant extracts resulted in the most rapid plant growth and highest phenolic content of pea seedlings. The chemical composition of the inoculant extracts was partially characterized.

Anti-diabetes functionality of Kefir culture-mediated fermented soymilk supplemented with Rhodiola extracts

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 correlated to high salidroside and low tyrosol contents. Angiotensin converting enzyme inhibitory activity seemed to change independent of tyrosol and salidroside contents with fermentation time. These results indicate that Kefir culture-mediated fermentation of soymilk supplemented with Rhodiola extracts resulted in mobilization of total phenolics, which could be effectively designed as complimentary therapies for postprandial hyperglycemia linked to Type II diabetes management. Due to the significantly reduced α-amylase inhibitory activity at the end of fermentation, this approach would have minimal side effects such as abdominal distention, flatulence, meteorism and possibly diarrhea, which are caused by the excessive inhibition of pancreatic α-amylase by current drug therapies.

Inhibition of Listeria monocytogenes by elite clonal extracts of oregano (origanum vulgare)

Food safety continues to be a major concern for the food industry in recent years. One of the industrys 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 action against Listeria monocytogenes in both broth and meat systems. Thymol and carvacrol, two of the main phenolic constituents of oregano extracts, were also tested in both systems to evaluate their activity against that of the whole oregano extract. Results indicate that thymol, carvacrol, and the clonal oregano line were all effective in inhibiting the growth of L. monocytogenes in both systems. Approximately 150–200 ppm of pure carvacrol or thymol was needed in order to significantly inhibit the growth of L. monocytogenes in broth, while at least 1200 ppm (corresponding to 27.8 μg phenolics/ml) of the elite clonal oregano extract was needed to do the same. Inconclusive results were obtained when the clonal line was compared to store-brand samples of oregano. In meat systems, 800 ppm of the oregano extract was able to significantly inhibit the growth of the pathogen more so than 800 ppm of carvacrol. A possible explanation for this is that the oregano extract was able to work more effectively at the interface of the lipid and water-soluble portions of the meat than the carvacrol. These results are promising for the food industry since we have now developed an approach for a highly consistent and reliable natural source of antimicrobial activity for future studies.

Enrichment of Phenolic Antioxidants and Anti-Helicobacter pylori Properties of Cranberry Pomace by Solid-State Bioprocessing

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 dietary management of H. pylori infections.

Sprouting and Solid-State Bioprocessing by Rhizopus oligosporus Increase the In Vitro Antibacterial Activity of Aqueous Soybean Extracts Against Helicobacter pylori

Abstract 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 2u2009d sprouting or 2u2009d R. oligosporus bioprocessing. Anti-H. pylori activity was not associated with antioxidant activity, but was linked to extracts when activity of the phenolic-polymerizing enzymes guaiacol peroxidase (in sprouted soybean extracts) and laccase (in R. oligosporus-bioprocessed soybean extracts) were the highest. This suggests the potential involvement of polymeric phenolics in the anti-H. pylori activity of soybean extracts and possible mechanisms for such action are discussed.