Lavender,tea tree and lemon oils as antimicrobials in washing liquids and soft body balms

The aim of this study was to evaluate the antimicrobial activity of commercial essential oils: lavender, tea tree and lemon, antimicrobials in washing liquid and O/W soft body balm. The inhibition efficacy of essential oils in washing liquid (1% alone or in mixtures), in soft body balm (0.5% alone), as well as combined with the synthetic preservative DMDM hydantoin and 3‐iodo‐2‐propynyl butyl carbamate mixture (0.1 and 0.3%), was tested against S. aureus ATCC 6538, P. aeruginosa ATCC 9027, Candida sp. ?OCK 0008 and A. niger ATCC 16404 in compliance with the European Pharmacopoeia standards. The components of the system preserving soft body balm were supplemented with a solubilizer. Washing liquids containing only essential oils met Criterion A E.P. only for S. aureus, Candida sp. and A. niger. In soft body balm formulations, oils at a concentration of 0.5% did not reveal any preserving activity. The introduction of a solubilizer to a system containing 0.5% tea tree oil led to a substantial increase in the bacteriostatic activity of the formulation, but did not significantly affect its fungistatic properties. A combination of 0.5% tea tree oil, 5% solubilizer and 0.3% synthetic preservative ensured the microbiological stability of soft body balm in accordance with Criterion A E.P.     

Dual inhibitions of lemon balm (<Emphasis Type="Italic">Melissa officinalis</Emphasis>) ethanolic extract on melanogenesis in B16-F1 murine melanocytes: Inhibition of tyrosinase activity and its gene expression

The effects of wild type and UV-irradiated lemon balm (Melissa officinalis) ethanolic extracts (MOE and UMOE) on melanogenesis in vitro were examined. UMOE showed potent antioxidant activity and significantly inhibited the mushroom and melanocyte tyrosinase activity, and lowered cellular melanin content by 49% at 200 μg/mL in B16-F1 melanocytes. The key gene and protein expression of tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2 were reduced (−73% for TRP-1 protein at 200 μg/mL UMOE, p<0.05). MOE showed similar results to a slightly lesser degree. We found that myo-inositol, a major compound in lemon balm extracts, significantly reduced cellular melanin synthesis and its effect was greater than arbutin at 1 mM. These suggest that both MOE and UMOE have anti-melanogenic role by both direct inhibition of tyrosinase and down-regulation of gene expressions in melanogenesis. UV-irradiation slightly improved the anti-melanogenic activities. UMOE may be useful as natural anti-melanogenic biomaterials for functional foods and cosmetics.     

Phenolic profiles of cultivated, in vitro cultured and commercial samples of Melissa officinalis L. infusions

Melissa officinalis L. (lemon balm) is normally consumed as an infusion and presents therapeutic properties, such as sedative, carminative and antispasmodic, also being included in some pharmaceutical preparations. The phenolic profiles of different samples of lemon balm, prepared as infusions, were evaluated by HPLC-DAD-ESI/MS. The profiles were compared in order to understand the differences between cultivated, in vitro cultured and commercial (bags and granulated) samples. All the samples showed a similar phenolic profile, presenting differences only in the quantities found of each compound. Rosmarinic acid was the most abundant compound, being higher in commercial samples, especially in tea bag sample (55.68 mg/g of infusion) and lower in in vitro cultured sample (15.46 mg/g). Moreover, dimers, trimers and tetramers of caffeic acid were identified and quantified for the first time in lemon balm. Only one flavonoid, luteolin-3′-O-glucuronide was found in all the samples, ranging from 8.43 mg/g in commercial granulate sample to 1.22 mg/g in in vitro cultured sample. Overall, cultivated and in vitro cultured samples presented the lowest amounts of phenolic compounds (59.59 and 30.21 mg/g, respectively); otherwise, commercial samples showed the highest contents (109.24 mg/g for tea bag and 101.03 mg/g for granulate sample). The present study shows that infusion of lemon balm can be a source of phenolic compounds, known for their bioactive effects.     

柠檬香蜂草精油的气相色谱-质谱联用分析及抑菌活性研究

该文采用水蒸气蒸馏萃取法(steam distillation,SD)对柠檬香蜂草提取精油,气相色谱-质谱联用(gas chromatograph-mass spectrometry,GC-MS)分析精油成分,制备成不同体积分数稀释液,通过纸片扩散法(kirby-bauer,K-B)测定柠檬香蜂草精油对3种食源性致病菌(金黄色葡萄球菌、大肠杆菌、四联球菌)的药物敏感性,筛选敏感菌株,最后稀释涂布平板法测定半数抑制浓度(50%inhibitory concentration,IC 50)。测得柠檬香蜂草精油中脂肪族占25.91%,芳香族占20.16%,萜类占53.93%。且其对金黄色葡萄球菌抑制作用最弱,对四联球菌抑制作用最强,在实验浓度范围内,抑制强度随精油浓度升高而升高,经计算,柠檬香蜂草精油对四联球菌的IC 50为457μg/mL。最终判断柠檬香蜂草精油对四联球菌有较好抑制作用,且起抑菌作用的物质为β-石竹烯、香茅醇和柠檬醛。     

Kombucha, the fermented tea: microbiology, composition, and claimed health effects

Kombucha is a slightly sweet, slightly acidic tea beverage consumed worldwide, but historically in China, Russia, and Germany. Kombucha is prepared by fermenting sweetened black tea preparations with a symbiotic culture of yeasts and bacteria. Potential health effects have created an increased interest in Kombucha. Yet, only a few research studies have shown that Kombucha has in vitro antimicrobial activity and enhances sleep and pain thresholds in rats. Furthermore, Kombucha consumption has proven to be harmful in several documented instances.     

Multielement analysis of Chinese tea (Camellia sinensis) by total-reflection X-ray fluorescence

 Total-reflection X–ray fluorescence (TXRF) was used for the simultaneous determination of 15 elements in tea samples which were produced either by acid digestion or acidified infusion of tea leaves (Camellia sinensis). The accuracy and precision of the method were checked by its application to a certified reference material (GBW 08505 : tea). A variety of 39 tea samples of different kinds and/or qualities produced in different regions of China were analysed. The range and mean of the concentrations of elements in the tea leaves (0.1–30.000 μg g^–1) and their solubility in infusions (0.5–85%) were determined and the influence of the origin, type and quality of the tea samples was studied. In some tea leaves produced in a Se-rich region, the content of Se was found to be very high (up to 7.5 μg g^–1), in contrast to a concentration of only about 0.1 μg g^–1 Se in most of the tea leaves examined. Received: 27 January 1998     

Antimicrobial activity of plant essential oils using food model media: Efficacy,synergistic potential and interactions with food components

The aim of this study was to optimise the antimicrobial efficacy of plant essential oils (EOs) for control of Listeria spp. and spoilage bacteria using food model media based on lettuce, meat and milk. The EOs evaluated were lemon balm, marjoram, oregano and thyme and their minimum inhibitory concentrations (MIC) were determined against Enterobacter spp., Listeria spp., Lactobacillus spp., and Pseudomonas spp. using the agar dilution method and/or the absorbance based microplate assay. MICs were significantly lower in lettuce and beef media than in TSB. Listeria strains were more sensitive than spoilage bacteria, and oregano and thyme were the most active EOs. EO combinations were investigated using the checkerboard method and Oregano combined with thyme had additive effects against spoilage organisms. Combining lemon balm with thyme yielded additive activity against Listeria strains. The effect of simple sugars and pH on antimicrobial efficacy of oregano and thyme was assessed in a beef extract and tomato serum model media. EOs retained greater efficacy at pH 5 and 2.32% sugar, but sugar concentrations above 5% did not negatively impact EO efficacy. In addition to proven antimicrobial efficacy, careful selection and investigation of EOs appropriate to the sensory profile of foods and composition of the food system is required. This work shows that EOs might be more effective against food-borne pathogens and spoilage bacteria when applied to foods containing a high protein level at acidic pH, as well as moderate levels of simple sugars.     

Evaluation of Least Squares Support Vector Machine Regression and other Multivariate Calibrations in Determination of Internal Attributes of Tea Beverages

This research aimed to explore the relationship between internal attributes (pH and soluble solids content) of tea beverages and diffuse reflectance spectra. Three multivariate calibrations including least squares support vector machine regression (LSSVR), partial least squares (PLS), and radial basis function (RBF) neural network were adopted for development of internal attributes determination models. Ten kinds of tea beverages including green tea and black tea were selected for visible and near infrared reflectance (Vis/NIR) spectroscopy measurement from 325 to 1,075 nm. As regard the kernel function, least squares–support vector machine regression models were built with both linear and RBF kernel functions. Grid research and tenfold cross-validation procedures were adopted for optimization of LSSVR parameters. The generalization ability of LSSVR models were evaluated by adjusting the number of samples in the training set and testing set, and sensitive wavelengths that were closely correlated with the internal attributes were explored by analyzing the regression coefficients from linear LSSVR model. Excellent LSSVR models were built with r = 0.998, standard error of prediction (SEP) = 0.111, for pH and r = 0.997, SEP = 0.256, for soluble solids content, and it can be found that the LSSVR models outperformed the PLS and RBF neural network models with higher accuracy and lower error. Six individual sensitive wavelengths for pH were obtained, and the corresponding pH determination model was developed with r = 0.994, SEP = 0.173, based on these six wavelengths. The soluble solids content determination model was also developed with r = 0.977, SEP = 0.173, based on seven individual sensitive wavelengths. The above results proved that Vis/NIR spectroscopy could be used to measure the pH and soluble solids content in tea beverages nondestructively, and LSSVR was an effective arithmetic for multivariate calibration regression and sensitive wavelengths selection.     

Simultaneous Determination of Sodium, Potassium, Manganese and Bromine in Tea by Standard Addition Neutron Activation Analysis

Standard addition method was applied for neutron activation analysis of tea leaves. Four brands of tea leaves were analyzed for its Na, K, Mn, and Br contents by this method. The Na, K, Mn, and Br concentrations were found to be in the 90–120 μg/g, 1.8–2.1% w/w, 150–500 and 3–7 μg/g ranges, respectively. The extraction efficiency of these elements, during the infusion, was calculated by analysis of tea leaves before and after the infusion process. It was observed that about 90% of the Na, K, and Br elements were extracted to water during the infusion process. The drinking tea is a rich source of Mn (despite of an extraction efficiency of 50% for this element).     

Chemical composition and in vitro antioxidative activity of a lemon balm (Melissa officinalis L.) extract

The leaf material of lemon balm (Melissa officinalis L.) was extracted with 450 ml/l aqueous ethanol by medium pressure liquid-solid extraction. The total phenolic content of the extract was estimated as gallic acid equivalents by Folin-Ciocalteu reagent method and a qualitative-quantitative compositional analysis was carried out using high performance liquid chromatography coupled with photodiode array detection. The lemon balm extract contained hydroxycinnamic acid derivatives and flavonoids with caffeic acid, m-coumaric acid, eriodictyol-7-O-glucoside, naringin, hesperidin, rosmarinic acid, naringenin, hesperetin being identified based on their chromatographic behaviour and spectral characteristics. The extract was also investigated for potential in vitro antioxidant properties in iron(III) reduction, iron(II) chelation, 1,1-diphenyl-2-picrylhydrazyl, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonate), superoxide anion and nitric oxide free-radical scavenging, and inhibition of β-carotene-linoleic acid bleaching assays. The extract demonstrated antioxidant activity in all the assays. However, it was not as potent as the positive controls except in the β-carotene-linoleic acid bleaching assay, where its activity was superior to that of gallic and caffeic acids and statistically indistinguishable from quercetin and BHA. The exceptionally high antioxidant activity and the fact that this assay is of biological relevance warrants further investigation of lemon balm extract in ex vivo and in vivo models of oxidative stress.     

Synergistic antimicrobial activity of galangal (Alpinia galanga), rosemary (Rosmarinus officinalis) and lemon iron bark (Eucalyptus staigerana) extracts

BACKGROUND: In this study the synergistic antimicrobial activities of combinations of extracts from galangal (Alpinia galanga), rosemary (Rosmarinus officinalis) and lemon iron bark (Eucalyptus staigerana) were evaluated against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, Salmonella typhimurium and Clostridium perfringens. Chemical compositions of these extracts were also determined to provide further insight into antimicrobial constituents and their potential mechanisms of action. RESULTS: Combinations of galangal with either rosemary or lemon iron bark showed synergistic antimicrobial activity. Specifically, galangal and rosemary showed synergistic activity against S. aureus and L. monocytogenes only, while galangal and lemon iron bark showed synergistic activity against E. coli and S. typhimurium. Chemical compositions of the extracts were determined by gas chromatographic–mass spectrometric analysis. The major chemical components of the galangal and lemon iron bark extracts were 1′‐acetoxy‐chavicol acetate (1′ACA) (63.4%) and neral (15.6%), respectively, while 1,8‐cineole (26.3%) and camphor (20.3%) were identified as major chemical components of the rosemary extract. CONCLUSION: The results of this study show that galangal, rosemary and lemon iron bark extracts contain components that may have different modes of antimicrobial action and combinations of these extracts may have potential as natural antimicrobials to preserve foods. Copyright © 2010 Society of Chemical Industry     

Antioxidant properties and total phenolics content of green and black tea under different brewing conditions

 The antioxidant activity and the total phenolics content of various tea extracts were analysed. Green and black tea were brewed from 0.5 min up to 10 min under different brewing conditions (stirring the extract, chopping the tea leaves before brewing). For measuring the antioxidant activity, the Trolox equivalent antioxidant capacity (TEAC) test and the low density lipoprotein (LDL) oxidation test were used. In all cases the antioxidant activity as well as the content of the phenolics increased with the brewing time. In black tea (brewed without stirring or chopping), the total phenolics increased from 33.8 mg/100 ml after 0.5 min up to 68.4 mg/100 ml after 10 min brewing time. Stirring during brewing led to higher phenolic yields in the extract. Thus, phenolics in stirred black tea ranged from 44.5 mg/100 ml (0.5 min) to 96.7 mg/100 ml (10 min). Chopping the tea leaves resulted in the highest content of phenolics. Antioxidant activity was well correlated with the corresponding total phenolics content. The results of the LDL oxidation test varied more than those of the TEAC test.     

Antioxidant properties and total phenolics content of green and black tea under different brewing conditions

 The antioxidant activity and the total phenolics content of various tea extracts were analysed. Green and black tea were brewed from 0.5 min up to 10 min under different brewing conditions (stirring the extract, chopping the tea leaves before brewing). For measuring the antioxidant activity, the Trolox equivalent antioxidant capacity (TEAC) test and the low density lipoprotein (LDL) oxidation test were used. In all cases the antioxidant activity as well as the content of the phenolics increased with the brewing time. In black tea (brewed without stirring or chopping), the total phenolics increased from 33.8 mg/100 ml after 0.5 min up to 68.4 mg/100 ml after 10 min brewing time. Stirring during brewing led to higher phenolic yields in the extract. Thus, phenolics in stirred black tea ranged from 44.5 mg/100 ml (0.5 min) to 96.7 mg/100 ml (10 min). Chopping the tea leaves resulted in the highest content of phenolics. Antioxidant activity was well correlated with the corresponding total phenolics content. The results of the LDL oxidation test varied more than those of the TEAC test. Received: 27 May 1998 / Revised version: 15 July 1998     

Efficacy of plant essential oils against foodborne pathogens and spoilage bacteria associated with ready-to-eat vegetables: antimicrobial and sensory screening

The objectives of this study were to evaluate the antimicrobial activity of plant essential oils (EOs) against foodborne pathogens and key spoilage bacteria pertinent to ready-to-eat vegetables and to screen the selected EOs for sensory acceptability. The EOs basil, caraway, fennel, lemon balm, marjoram, nutmeg, oregano, parsley, rosemary, sage, and thyme were evaluated. The bacteria evaluated were Listeria spp., Staphylococcus aureus, Lactobacillus spp., Bacillus cereus, Salmonella, Enterobacter spp., Escherichia coli, and Pseudomonas spp. Quantitative antimicrobial analyses were performed using an absorbance-based microplate assay. Efficacy was compared using MIC, the half maximum inhibitory concentration, and the increase in lag phase. Generally, gram-positive bacteria were more sensitive to EOs than were gram-negative bacteria, and Listeria monocytogenes strains were among the most sensitive. Of the spoilage organisms, Pseudomonas spp. were the most resistant. Oregano and thyme EOs had the highest activity against all the tested bacteria. Marjoram and basil EOs had selectively high activity against B. cereus, Enterobacter aerogenes, E. coli, and Salmonella, and lemon balm and sage EOs had adequate activity against L. monocytogenes and S. aureus. Within bacterial species, EO efficacy was dependent on strain and in some cases the origin of the strain. On a carrot model product, basil, lemon balm, marjoram, oregano, and thyme EOs were deemed organoleptically acceptable, but only oregano and marjoram EOs were deemed acceptable for lettuce. Selected EOs may be useful as natural and safe additives for promoting the safety and quality of ready-to-eat vegetables.     

Tea,Kombucha, and health: a review

Kombucha is a refreshing beverage obtained by the fermentation of sugared tea with a symbiotic culture of acetic bacteria and fungi, consumed for its beneficial effects on human health. Research conducted in Russia at the beginning of the century and testimony indicate that Kombucha can improve resistance against cancer, prevent cardiovascular diseases, promote digestive functions, stimulate the immune system, reduce inflammatory problems, and can have many other benefits. In this paper, we report on studies that shed more light on the properties of some constituents of Kombucha. The intensive research about the effects of tea on health provide a good starting point and are summarized to get a better understanding of the complex mechanisms that could be implicated in the physiological activity of both beverages.     

Characteristics and upregulation of antioxidant enzymes of kitchen mint and oolong tea kombucha beverages

Kombucha is a healthy traditional beverage which is made by fermenting products with a symbiotic culture of acetic acid bacteria and yeasts. In present study, leaves of kitchen mint (Mentha cordifolia Opiz. Ex Fresen) and leaves of oolong tea (Camellia sinensis) were fermented in kombucha formula. After fermentation, titratable acidity contents and ethanol of kitchen mint, oolong tea, and mixtures of oolong tea and kitchen mint kombucha samples gradually increased with a period of fermentation time. At day 14 of fermentation, phenolic compounds and flavonoids were increased in all kombucha samples. The numbers of acetic acid bacteria and yeast in kombucha had gradually raised during 7–14 days of fermentation. DPPH and ABTS scavenging activities of these kombucha increased over a period of fermentation time and shown the highest antioxidant capacity on day 14 of fermentation. In addition, all kombucha samples exhibited the antioxidant effects by attenuating H₂O₂-induced ROS production, increasing mRNA expression of catalase, glutathione reductase (GRe), and Mn-SOD, and inducing GRe enzymatic activity in HEK-293 cells. Kombucha beverage can be used as the healthy beverages for attenuation of oxidative stress in many diseases.     

Cashew apple juice: its use in fortifying the nutritional quality of some tropical fruits

The physico-chemical properties of some tropical fruits (pineapple, orange, grape, mango and lemon) were analyzed and compared with those of cashew apple. Cashew apple juice was found to contain the highest amount of vitamin C (203.5 mg/100 ml) of edible portion. Orange, grape, pineapple, mango and lemon contained average values of 54.7 mg, 45.0 mg, 14.70 mg, 30.9 mg and 33.7 mg vitamin C per 100 ml of juice respectively. Obviously, cashew apple juice contains almost four times the amount of vitamin C in the popular citrus fruits and more than four times as much vitamin C as in other fruits. Hence, when cashew apple was blended with other tropical fruits it boosted their nutritional quality. On the other hand, these fruits improved the acceptability of cashew juice in terms of taste and flavour. The blends, even though significantly different (P <0.05) in taste, colour and mouthfeel, were all acceptable to consumers with no significant difference (P>0.05) in overall acceptability. Received: 16 August 1999 / Revised version: 2 November 1999     

Antioxidant activity of fresh and dry herbs of some Lamiaceae species

The herbs of lemon balm, oregano, and peppermint were analysed immediately after harvest and after drying to determine their antioxidant activity and content of total phenolics, l-ascorbic acid, and carotenoids. The strongest inhibition of linoleic acid (LA) peroxidation was found for fresh and dried oregano. For peppermint and lemon balm it was significantly lower and decreased after drying. The ability to scavenge the free radical DPPH (2,2-diphenyl-1-picrylhydrazyl) was very high in almost all tested samples, exceeding 90%. The three species tested had a very high content of total phenolics and drying of oregano and peppermint resulted in their considerable increase. The highest content of ascorbic acid was determined in fresh peppermint and lemon balm and carotenoid content was at a similar level in all the species tested. Drying caused great losses of these compounds.     

Physico-chemical Properties, Vitamin C Content, and Antimicrobial Properties of Pomegranate Fruit (Punica granatum L.)

Pomegranate (Punica granatum L.) fruit is widely used in the food and process industries due to its excellent nutritional and health value and as a raw material for the manufacture of secondary products such as jellies, dyes, and cosmetics. The objectives of this research were to determine the vitamin C content and antimicrobial properties of fresh and dried fractions of fruit peel and arils of locally grown and imported pomegranate in Oman. A significant variation in vitamin C content was found among the five varieties of pomegranate studied, ranging from 52.8 to 72.0 mg/100 g fresh weight (fw) for arils and 76.8 to 118.4 mg/100 g fw for peels. Irrespective of the variety of pomegranate, vitamin C content in the peel was significantly higher than the aril, with differences ranging from 24.4% to 97.0% depending on variety. Fruit fractions showed antimicrobial effects (inhibition zone) on Staphylococcus aureus and Pseudomonas aeruginosa but not Escherichia coli. Sun drying of fruit peel significantly (p ≤ 0.05) enhanced vitamin C retention and antimicrobial effects in comparison with oven drying presumably due to lower rate of moisture removal associated with low temperature drying over longer duration in comparison with short-time high-temperature oven drying.