On the effects of a plant extract of Orthosiphon stamineus on sebum‐related skin imperfections

Overproduction of sebum is very common and results in an undesirable oily, shiny complexion with enlarged pores. Sebum secretion is basically under the control of 5‐α reductase, and more particularly under that of type 1 isozyme. But it is also highly sensitive to environmental factors such as temperature, humidity and food. Moreover, in Asia, the edicts of a flawless facial skin turn oily skin into a major concern for Asian women. We identified Orthosiphon stamineus leaf extract as an interesting ingredient for reducing the oily appearance of skin thanks to its ability to reduce 5‐α reductase type 1 expression in normal human epidermal keratinocytes in vitro. This was confirmed ex vivo, where Orthosiphon stamineus leaf extract was shown to reduce 5‐α reductase activity as well as the production of squalene, one of the main components of sebum that was used as a tracer of sebum. To evaluate the efficacy of Orthosiphon stamineus leaf extract at reducing sebum‐related skin imperfections in vivo, we performed two different clinical studies, one in France on a panel of Caucasian volunteers and the other one in Thailand on a panel of Asian volunteers. Using instrumental techniques as well as clinical evaluation and self‐evaluation, we could highlight that an O/W cosmetic formula containing 2% of Orthosiphon stamineus leaf extract could visibly reduce the oily appearance of skin as well as the size of pores, thus leading to a significant improvement of complexion evenness and radiance. Overall, the results obtained were better than those observed with the same formula containing 1% of zinc gluconate, an ingredient frequently used in oily skin care products.     

Antibiofilm formation and anti‐adhesive (to HEp‐2 cells) effects of rosemary water extract against some food‐related pathogens

The present work aimed to determine the bioactive compounds in two rosemary water extracts (RWE1 and RWE2) and to assess their antimicrobial, anti‐adhesive and antibiofilm potentials against the food‐related Bacillus and Pseudomonas species at concentrations; 4, 8, 12, 16 and 20 mg mL^?1. Phenolic compounds and isoflavones in the RWEs were determined using HPLC. The concentrations of most bioactive compounds of RWE1 (benzoic, ellagic, gallic and rosmarinic acids, daidzein and genistein) were higher than that of RWE2. The MIC₉₀ of RWE1 and RWE2 against all tested bacteria was 12 and 16 mg mL^?1, respectively. The anti‐adhesive and antibiofilm doses were higher than MIC₉₀. RWE1 and RWE2 showed potential reduction in the bacterial cell adhesion to HEp‐2 cells – 17.5–64.7 and 12.2–52.9%, respectively. In conclusion, this study emphasises the effective use of RWE as a natural anti‐adhesive and antibiofilm agent against Bacillus and Pseudomonas, without difficult extraction procedure.     

Effects of cocoa extract containing polyphenols and methylxanthines on biochemical parameters of obese‐diabetic rats

BACKGROUND: Previous studies have indicated that cocoa extract possesses hypoglycaemic and hypocholesterolaemic properties in streptozotocin‐induced diabetic rats. However, there has been limited research on the effects of cocoa extract on obese‐diabetic (Ob‐db) rats that mimic human diabetes syndrome. Hence this study was initiated to determine the effect of cocoa extract containing polyphenols and methylxanthines on several biochemical parameters, namely glucose level, insulin sensitivity and lipid profiles of Ob‐db rats. RESULTS: Intake of cocoa extract supplemented with polyphenols (2.17 mg epicatechin, 1.52 mg catechin, 0.25 mg dimer and 0.13 mg trimer g^?1 cocoa extract) and methylxanthines (3.55 mg caffeine and 2.22 mg theobromine g^?1 cocoa extract) for 4 weeks significantly (P < 0.05) reduced the plasma total cholesterol, triglycerides and low‐density lipoprotein cholesterol of obese‐diabetic rats (Ob‐db + cocoa) compared with non‐supplemented animals (Ob‐db). Short‐term (acute) supplementation of cocoa extract significantly (P < 0.05) reduced the plasma glucose level at 60 and 90 min compared with untreated rats as assessed by the oral glucose tolerance test. However, no significant differences were observed in plasma glucose level, insulin level and insulin sensitivity after chronic (4 weeks) cocoa extract supplementation. CONCLUSION: The results of this study suggest that cocoa extract possesses hypocholesterolaemic properties and can exert a transient glucose‐lowering effect but not long‐term glucose control. Copyright © 2008 Society of Chemical Industry     

Different response to acetic acid stress in Saccharomyces cerevisiae wild‐type and l‐ascorbic acid‐producing strains

Biotechnological processes are of increasing significance for industrial production of fine and bulk chemicals, including biofuels. Unfortunately, under operative conditions microorganisms meet multiple stresses, such as non‐optimal pH, temperature, oxygenation and osmotic stress. Moreover, they have to face inhibitory compounds released during the pretreatment of lignocellulosic biomasses, which constitute the preferential substrate for second‐generation processes. Inhibitors include furan derivatives, phenolic compounds and weak organic acids, among which acetic acid is one of the most abundant and detrimental for cells. They impair cellular metabolism and growth, reducing the productivity of the process: therefore, the development of robust cell factories with improved production rates and resistance is of crucial importance. Here we show that a yeast strain engineered to endogenously produce vitamin C exhibits an increased tolerance compared to the parental strain when exposed to acetic acid at moderately toxic concentrations, measured as viability on plates. Starting from this evidence, we investigated more deeply: (a) the nature and levels of reactive oxygen species (ROS); (b) the activation of enzymes that act directly as detoxifiers of reactive oxygen species, such as superoxide dismutase (SOD) and catalase, in parental and engineered strains during acetic acid stress. The data indicate that the engineered strain can better recover from stress by limiting ROS accumulation, independently from SOD activation. The engineered yeast can be proposed as a model for further investigating direct and indirect mechanism(s) by which an antioxidant can rescue cells from organic acid damage; moreover, these studies will possibly provide additional targets for further strain improvements. Copyright © 2013 John Wiley & Sons, Ltd.     

Off‐flavour development in soybeans: comparative role of some antioxidants and related enzymes

Off‐flavour development is the major impediment in the effective use of soybeans as food ingredients. In the present study, the levels of vitamin E and vitamin C along with those of antioxidant enzymes, like superoxide dismutase, peroxidase and catalase, were estimated in sixteen soybean varieties to explore their effectiveness against off‐flavour generation. Thiobarbituric acid (TBA) number, an indicator of lipid peroxidation, was used to measure the quality with respect to off‐flavour. Data on activities of various antioxidant enzymes indicated that the off‐flavour is mainly generated enzymatically by the action of lipoxygenase on polyunsaturated fatty acids. Furthermore, varieties PK 416 and JS 7105 had the highest level of vitamin E while their TBA number was the lowest indicating the inverse relationship between the two parameters. It was further observed that the peroxidative effect of higher vitamin C concentrations is controlled by vitamin E. Among the varieties analyzed, PK 416 and JS 7105 appeared to have greater potential as most acceptable food ingredients. Copyright © 2004 Society of Chemical Industry     

Modulation of lipid metabolism by polyphenol‐rich grape skin extract improves liver steatosis and adiposity in high fat fed mice

This study investigated the influence of polyphenol‐rich grape skin extract (GSE) on adiposity and hepatic steatosis in mice fed a high fat diet (HFD) and its underlying mechanisms based on adipose and hepatic lipid metabolism. C57BL/6J mice were fed a normal diet or a HFD (20% fat, w/w) with or without GSE (0.15%, w/w) for 10 weeks. The supplementation of GSE significantly lowered body weight, fat weight, plasma free fatty acid level, and hepatic lipid accumulation compared to the HFD group. Plasma leptin level was significantly lower, while the plasma adiponectin level was higher in the GSE group than in the HFD group. GSE supplementation significantly suppressed the activities of lipogenic enzymes in both adipose and liver tissues, which was concomitant with β‐oxidation activation. Furthermore, GSE reversed the HFD‐induced changes of the expression of genes involved in lipogenesis and β‐oxidation in the liver. These findings suggest that GSE may protect against diet‐induced adiposity and hepatic steatosis by regulating mRNA expression and/or activities of enzymes that regulate lipogenesis and fatty acid oxidation in the adipose tissue and liver.     

Cranberry extract and quercetin modulate the expression of cyclooxygenase‐2 (COX‐2) and IκBα in human colon cancer cells

BACKGROUND: Cranberry (Vaccinium marcocarpon) fruit and quercetin, a major flavonoid found in cranberries, are likely contributors to chemoprevention, and their anti‐inflammatory activities may play a potential role in colon cancer prevention. The aim of this study was to examine the effect of cranberry extract and quercetin on basal expression of cyclooxygenase‐2 (COX‐2) and IκBα as well as the effect on phorbol 12‐myristate 13‐acetate (PMA)‐induced COX‐2 expression in colon cancer cells. RESULTS: HT‐29 human colon adenocarcinoma cells were treated with various concentrations of cranberry extract or quercetin and/or PMA, and the protein expression of COX‐2 and IκBα was determined. The results indicated that cranberry extract and quercetin decreased COX‐2 expression and suppressed degradation of IκBα in unstimulated cells. In PMA‐stimulated cells, cranberry extract was also able to decrease COX‐2 expression and suppress degradation of IκBα. CONCLUSION: The results suggest that a possible mechanism involved in the anti‐cancer activity of cranberry and quercetin is partly mediated through its anti‐inflammatory action. These findings indicate that cranberry and quercetin may reduce the risk of colon cancer possibly by suppressing inflammatory responses. Copyright © 2008 Society of Chemical Industry     

Antibacterial Effect of Grapefruit Seed Extract (GSE) on Makgeolli‐Brewing Microorganisms and Its Application in the Preservation of Fresh Makgeolli

To develop a new preservation method, the antimicrobial activity of grapefruit seed extract (GSE) against Makgeolli‐brewing microorganisms and food‐borne pathogens was assessed, and a general analysis and sensory evaluation of fresh Makgeolli with added GSE was made. The minimum inhibitory concentration (MIC) values of GSE against 10 strains of Makgeolli‐brewing microorganism were 0.0122 to 1.5625 μL/mL. The MIC values against 6 strains of food‐borne pathogens were 0.0061 to 0.7813 μL/mL. On addition of 0.1% (v/v) and 0.2% GSE in bottled fresh Makgeolli, no significant difference in the pH, or the contents of total acids, ethanol, or methanol in the Makgeolli, were observed compared with control Makgeolli (with no GSE), during the preservation period (8 weeks) at 10 °C. In the Makgeolli with 0.1% and 0.2% GSE, the total bacterial counts decreased significantly by 4.9% (P < 0.01) and 11.2% (P < 0.001), respectively, versus the control. The decreases in yeast count were significantly lessened by 15.33% and 15.24% (both P < 0.001), respectively, after 8 weeks of storage, compared with the control. In the sensory evaluation of Makgeolli with 0.1% and 0.2% GSE, the refreshment and overall acceptability received significantly better scores than the control (P < 0.01), with no change in sweetness, bitterness, sourness, turbidity, color, or odor. These results suggest that GSE controls the growth of Makgeolli‐brewing microorganisms and extends the shelf life (ca. 2 wk), without decreasing overall acceptance.     

Nitrogen starvation induces expression of Lg‐FLO1 and flocculation in bottom‐fermenting yeast

When exponentially growing cells of bottom‐fermenting yeast were starved for nitrogen or were grown on proline (a non‐preferred nitrogen source), flocculation was induced. This flocculation was not induced by starvation for either carbon or amino acids. Expression of Lg‐FLO1, which is required for flocculation of bottom‐fermenting yeast, was also found to be induced by starvation for nitrogen. This suggests that the flocculation of bottom‐fermenting yeast is under the control of a nitrogen catabolite repression (NCR)‐like mechanism. Copyright © 2012 John Wiley & Sons, Ltd.