An in vitro study on the dental caries preventing effect of oligomeric procyanidins in sorghum episperm

Xu, Liman; Liu, Rui; Li, Duandan; Tu, Shi Ming; Chen, Jing

doi:10.1016/j.foodchem.2010.11.075

Cited by 16 publications

(8 citation statements)

References 25 publications

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“…Identification of the phenolic compounds was based on comparing their mass spectral data with data from literature (Lazarus, Adamson, Hammerstone & Schmitz, 1999;Hammerstone, Lazarus, Mitchell, Rucker & Schmitz, 1999;Xu, Liu, Li, Tu & Chen, 2011) and the polyphenol database Phenol Explorer (Rothwell et al, 2013). Quantification of the compounds could not be carried out due to lack of higher oligomeric and polymeric standards.…”

Section: Normal Phase Hplc and Lc/ms Of Polyphenols From Naoh Treatedmentioning

confidence: 99%

Inactivation of tannins in milled sorghum grain through steeping in dilute NaOH solution

2015

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.Running title: Tannin inactivation in milled sorghum grain with dilute NaOH 1 Highlights  Steeping milled Type III tannin sorghum in NaOH solution reduces tannin content  NaOH treatment substantially reduces α-amylase inhibition by the tannins  Tannin polymerization was found to be the mechanism of inactivation  NaOH treatment could enable use of Type III tannin sorghum in bioethanol production 2 ABSTRACTSteeping milled sorghum in up to 0.4% NaOH was investigated as a method of tannin inactivation. NaOH steeping substantially reduced assayable total phenols and tannins in both Type III and Type II sorghums and with Type III sorghum caused a 60-80% reduction in α-amylase inhibition compared to a 20% reduction by water steeping. NaOH treatment also reduced starch liquefaction time and increased free amino nitrogen. Type II tannin sorghum did not inhibit α-amylase and consequently the NaOH treatment had no effect. HPLC and LC-MS of the tannin extracts indicated a general trend of increasing proanthocyanin/procyanidin size with increasing NaOH concentration and steeping time, coupled with a reduction in total area of peaks resolved. These show that the NaOH treatment forms highly polymerised tannin compounds, too large to assay and to interact with the α-amylase. NaOH pre-treatment of Type III sorghums could enable their utilization in bioethanol production.

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Section: Normal Phase Hplc and Lc/ms Of Polyphenols From Naoh Treatedmentioning

confidence: 99%

Inactivation of tannins in milled sorghum grain through steeping in dilute NaOH solution

2015

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“…Polyphenols occurring in fruits, nuts, vegetables, and flowers have antioxidant activity. − The phenolic hydroxyl group in their structures acts as a hydrogen donor, and they can effectively scavenge free radicals. , The beneficial antioxidative activity of polyphenols has been well studied and applied to health promotion. − Besides the antioxidative activity, some polyphenols are also antimicrobial and antiviral. − In our previous study, it was demonstrated that the antimicrobial activity of polyphenols, such as gallic acid and proanthocyanidin, was considerably enhanced by blue light irradiation at a wavelength of around 400 nm. , When Staphylococcus aureus suspended in an aqueous solution of the polyphenols was exposed to blue light, they were killed with a >5 log reduction of viable counts within 15–30 min.…”

Section: Introductionmentioning

confidence: 99%

Bactericidal Activity and Mechanism of Photoirradiated Polyphenols against Gram-Positive and -Negative Bacteria

Nakamura

Ishiyama

Sheng

et al. 2015

J. Agric. Food Chem.

113

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The bactericidal effect of various types of photoirradiated polyphenols against Gram-positive and -negative bacteria was evaluated in relation to the mode of action. Gram-positive bacteria (Enterococcus faecalis, Staphylococcus aureus, and Streptococcus mutans) and Gram-negative bacteria (Aggregatibacter actinomycetemcomitans, Escherichia coli, and Pseudomonas aeruginosa) suspended in a 1 mg/mL polyphenol aqueous solution (caffeic acid, gallic acid, chlorogenic acid, epigallocatechin, epigallocatechin gallate, and proanthocyanidin) were exposed to LED light (wavelength, 400 nm; irradiance, 260 mW/cm(2)) for 5 or 10 min. Caffeic acid and chlorogenic acid exerted the highest bactericidal activity followed by gallic acid and proanthocyanidin against both Gram-positive and -negative bacteria. It was also demonstrated that the disinfection treatment induced oxidative damage of bacterial DNA, which suggests that polyphenols are incorporated into bacterial cells. The present study suggests that blue light irradiation of polyphenols could be a novel disinfection treatment.

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“…By contrast, proanthocyanidin treatment without laser irradiation did not exert bactericidal effect. Although the antimicrobial activity of proanthocyanidin alone was reported in previous studies [9], [10], [20], it is known that the activity is moderate and it takes long time, at least several hours, to kill S. aureus with a >5-log reduction [8]. Although the laser irradiation performed in the present study could kill the bacteria, the bactericidal effect (<2-log reduction of the CFU/mL in 30 min) was weaker than that of photo-irradiated proanthocyanidin.…”

Section: Discussionmentioning

confidence: 85%

Photo-Irradiation of Proanthocyanidin as a New Disinfection Technique via Reactive Oxygen Species Formation

et al. 2013

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In the present study, the bactericidal effect of photo-irradiated proanthocyanidin was evaluated in relation to reactive oxygen species formation. Staphylococcus aureus suspended in proanthocyanidin aqueous solution was irradiated with light from a laser at 405 nm. The bactericidal effect of photo-irradiated proanthocyanidin depended on the concentration of proanthocyanidin, the laser irradiation time, and the laser output power. When proanthocyanidin was used at the concentration of 1 mg/mL, the laser irradiation of the bacterial suspension could kill the bacteria with a >5-log reduction of viable cell counts. By contrast, bactericidal effect was not observed when proanthocyanidin was not irradiated. In electron spin resonance analysis, reactive oxygen species, such as hydroxyl radicals, superoxide anion radicals, and hydrogen peroxide, were detected in the photo-irradiated proanthocyanidin aqueous solution. The yields of the reactive oxygen species also depended on the concentration of proanthocyanidin, the laser irradiation time, and the laser output power as is the case with the bactericidal assay. Thus, it is indicated that the bactericidal effect of photo-irradiated proanthocyanidin is exerted via the reactive oxygen species formation. The bactericidal effect as well as the yield of the oxygen radicals increased with the concentration of proanthocyanidin up to 4 mg/mL, and then decreased with the concentration. These findings suggest that the antioxidative activity of proanthocyanidin might prevail against the radical generation potency of photo-irradiated proanthocyanidin resulting in the decreased bactericidal effect when the concentration is over 4 mg/mL. The present study suggests that photo-irradiated proanthocyanidin whenever used in an optimal concentration range can be a new disinfection technique.

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An in vitro study on the dental caries preventing effect of oligomeric procyanidins in sorghum episperm

Cited by 16 publications

References 25 publications

Inactivation of tannins in milled sorghum grain through steeping in dilute NaOH solution

Inactivation of tannins in milled sorghum grain through steeping in dilute NaOH solution

Bactericidal Activity and Mechanism of Photoirradiated Polyphenols against Gram-Positive and -Negative Bacteria

Photo-Irradiation of Proanthocyanidin as a New Disinfection Technique via Reactive Oxygen Species Formation

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