Antimicrobial effect of rosemary extracts

A rosemary extract commercially exploited (Oxy'less) as an antioxidant of lipids in foods was dissolved in ethanol (100 mg/ml), and the solution was tested against foodborne microorganisms. For gram-positive bacteria, the MIC of the ethanolic solution was 1% for Leuconostoc mesenteroides, 0.5% for Listeria monocytogenes, 0.5% for Staphylococcus aureus, 0.13% for Streptococcus mutans, and 0.06% for Bacillus cereus. It slowed the growth of Penicillium roquefortii and Botrytis cinerea. Up to 1% of the ethanolic solution had no activity on the gram-negative bacteria Escherichia coli, Salmonella Enteritidis, and Erwinia carotovora and on the yeasts Rhodotorula glutinis and Cryptococcus laurentii. Antibacterial activity of the rosemary extract was strongly influenced by the composition of the media. The MIC was reduced by low pH, high NaCl contents, and low temperatures. Low pH and high NaCl concentration had a synergistic effect on the MIC of the rosemary extract for S. aureus. Lipids, surface-active agents, and some proteins decreased its antibacterial activity, whereas pectin had no effect. The inhibitory effect was little modified by heat treatment (100 degrees C). The natural microflora of pasteurized zucchini broth was inhibited by 0.5% of the rosemary extract. The antibacterial activity was linked to the compounds extracted with hexane, which are presumably phenolic diterpenoids.     

Spray-dried rosemary extracts: Physicochemical and antioxidant properties

In this work, spray-dried rosemary extracts were obtained. A 3³ Box-Behnken design was followed to evaluate the influence of drying conditions on the contents of chemical markers and “in vitro” antioxidant activity of the powder. Although the dry products lost some of their polyphenols, they still had antioxidant activities (IC₅₀) ranging from 17.6 to 24.8 μg · mL⁻¹. Analysis of variance proved that studied factors and some of their interactions significantly affected most of the quality indicators. The best combination of conditions to use for obtaining dry rosemary extracts with adequate physicochemical and functional properties involves an extract feed rate of 6 mL · min⁻¹, a drying air inlet temperature of 140 °C and a spray nozzle air flow rate of 50 L · min⁻¹.     

Capillary electrophoresis separation of rosemary antioxidants from subcritical water extracts

In this work, the possibilities of the combined use of subcritical water extraction (SWE) and capillary electrophoresis (CE) are established through the separation of antioxidants from rosemary (Rosmarinus officinalis L.). A new CE method is developed that allows the separation of different antioxidants found in the SWE fractions. The CE method is reproducible, efficient and fast, allowing the analysis of complex rosemary extracts in less than 16 min. The CE method is compared with a published reversed-phase high-performance liquid chromatography (RP-HPLC) procedure, both using diode-array detection. The main advantages of CE compared with HPLC are its higher resolving power and its different selectivity, which is demonstrated to be useful for the detection of some very polar compounds that cannot be analyzed by RP-HPLC. Moreover, the possibilities of the CE approach for following the degradation of antioxidants is also demonstrated. To our knowledge, this is the first work showing the high potential of the combined use of SWE and CE.     

A safety study of oral xanthohumol administration and its influence on fertility in Sprague Dawley rats

Xanthohumol (XN) is a prenylated chalcone, which has been shown to possess a broad range of potential cancer preventive and additional biological activities. In the present study, we have determined the subchronic 4-wk toxicity of XN and monitored its influence on fertility and development of offspring in two fertility studies. Four-week-old female Sprague Dawley (SD) rats were treated with 0.5% XN in the diet or with 1,000 mg XN/kg body weight (b.w.) per day by gavage for 28 days. No remarkable treatment-related changes in general appearance and b.w. occurred during the study. After autopsy, liver, kidney, lung, heart, stomach, and spleen were examined macroscopically and histopathologically. Relative liver weights of animals in both treatment groups were significantly reduced by 30--40% in comparison with the control group, indicating weak hepatotoxicity. Also, mammary glands of treated rats appeared less developed compared to the controls. Consequently, we investigated the influence of XN on rat reproduction. In two fertility studies, XN (100 mg/kg b.w. per day), given either for 4 wk prior to or during mating, gestation, and nursing, did not cause any adverse effects on female reproduction and the development of offspring. Noteworthy, treatment of male rats prior to mating significantly (p=0.027) increased the sex ratio of male to female offspring. Overall, lifelong treatment at a daily dose of 100 mg/kg b.w. in a two-generation study did not affect the development of SD rats.     

Effect of addition of commercial rosemary extracts on potent odorants in cooked beef

Solid-phase microextraction-gas chromatography-olfactometry (SPME-GCO) and aroma extract dilution analysis (AEDA) were applied to measure the effects of the addition of two commercial rosemary extracts (RE) on the potent odorants in cooked beef extracts (BE). On the basis of the results of SPME-GCO and AEDA, the addition of RE imparted sweet and floral notes to BE as a result of the addition of esters and terpenes of RE. In addition, RE suppressed the formation of odorants derived via lipid oxidation and Maillard reactions. The most potent lipid oxidation volatiles consisted of 1-octen-3-one (mushroom-like), (E)-2,4-epoxy-(E)-2-decenal (metallic), and eight different aldehydes (fatty). The Maillard reaction volatiles, necessary for typical cooked beef flavor, included compounds with meaty [2-methyl-3-furanthiol, 2-methyl-3-(methylthio)furan, 2-methyl-3-(methyldithio)furan], roasty (2-furanmethanethiol), caramel-like [4-hydroxy-2,5-dimethyl-3(2H)-furanone], baked potato-like [3-(methylthio)propanal], and spicy [3-hydroxy-4,5-dimethyl-2(5H)-furanone] attributes. The suppressive effects of RE may be caused by the action of antioxidative substances in RE alone or in combination with the pH increase in BE induced by the matrix components of RE.     

Antioxidant effects of rosemary extracts on sunflower oil compared with synthetic antioxidants

The antioxidant activities of ethanol extracts of rosemary (Rosmarinus officinalis L.) (RE) were tested in natural sunflower oil stored at 60 °C by measuring their peroxide values (POV), thiobarbituric acid‐reactive substances (TBARS), free fatty acid (FFA) content and p‐anisidine value (AnV) after regular intervals compared with synthetic antioxidants. After 3 weeks of storage at 60 °C, sunflower oil containing 200 mg kg^?1 rosemary extracts showed lower POVs (75.7 ± 0.47  meq kg^?1), thiobarbituric acid‐reactive substances (TBARS)(0.161 ± 0.002 μg mL^?1), FFA contents (0.45 ± 0.04 mg g^?1) and AnV (12.4 ± 0.02) than the control sample. Sunflower oil containing 200 ppm butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert‐butylhydroquinone (TBHQ) showed POVs (204 ± 0.68, 159 ± 0.55, 20 ± 0.49 meq kg^?1), thiobarbituric acid‐reactive substances (TBARS) (0.171 ± 0.002, 0.184 ± 0.002, 0.069 ± 0.001 μg mL^?1), FFA contents (0.34 ± 0.03, 0.46 ± 0.03, 0.2 ± 0.01 mg g^?1) and AnV (14.7 ± 0.03, 16.5 ± 0.04, 6.77 ± 0.01), respectively, after 3 weeks of storage at 60 °C. These results illustrate that rosemary extracts exhibited very strong antioxidant activity, almost equal to that of synthetic antioxidants (BHA and BHT).     

迷迭香提取物与微胶囊化对鸡油抗氧化作用的研究

以鸡油为原料,主要研究了迷迭香提取物,没食子酸以及微胶囊化对鸡油的抗氧化作用.研究结果表明,天然香辛料迷迭香提取物对鸡油具有抗氧化作用,最适添加量为0.018％;迷迭香提取物与没食子酸联合使用时,对鸡油具有协同抗氧化作用,且没食子酸适宜添加量为0.1％;微胶囊化对鸡油有一定的抗氧化作用,与迷迭香提取物联合使用时对鸡油有协同抗氧化作用;通过微胶囊评价分析实验,发现鸡油微胶囊化的最佳壁材为辛烯基琥珀酸淀粉,最佳包埋量为50％.     

迷迭香提取物对水酶法提取的植物油抗氧化性的影响

研究两种不同溶剂(甲醇和乙醇)提取的迷迭香提取物,对五种水酶法制得植物油抗氧化性的影响。通过脂肪酸组成、氧化诱导时间、DPPH自由基清除能力、ABTS+自由基清除能力等指标,对油样抗氧化性进行评价。结果表明,两种溶剂提取的迷迭香提取物均可以有效提高水酶法制得植物油的抗氧化能力,其中甲醇作为溶剂的迷迭香提取物抗氧化能力较强。     

迷迭香提取物对水酶法提取的植物油抗氧化性的影响

研究两种不同溶剂（甲醇和乙醇）提取的迷迭香提取物,对五种水酶法制得植物油抗氧化性的影响。通过脂肪酸组成、氧化诱导时间、DPPH自由基清除能力、ABTS+自由基清除能力等指标,对油样抗氧化性进行评价。结果表明,两种溶剂提取的迷迭香提取物均可以有效提高水酶法制得植物油的抗氧化能力,其中甲醇作为溶剂的迷迭香提取物抗氧化能力较强。      

Oregano and rosemary extracts inhibit oxidation of long-chain n-3 fatty acids in menhaden oil

ABSTRACT:  Capabilities of methanol extracts from oregano and rosemary in retarding oxidation of long-chain polyunsaturated fatty acids, docosahexaenoic acid C22:6 (DHA) and eicosapentaenoic acid C20:5 (EPA), in menhaden oil were investigated. The fish oils after mixing with the extracts at different concentrations were oxidized in an accelerated study by heating at 150 °C for 30 min or incubating at 60 °C for 5 d. After heating at 150 °C, only 15.9% of DHA and 18.5% of EPA remained in the fish oil without extract, while 38.8% to 65.9% of DHA and 44.7% to 69.0% of EPA were retained in the fish oil mixed with 1% to 5% of oregano extract. The highest retained DHA (56.9%) and EPA (58.0%) in the fish oils mixed with rosemary extract were observed at 2.5% addition. Increasing rosemary extract to 5% lowered its capability of inhibiting DHA and EPA oxidation. After incubation at 60 °C for 5 d, the highest inhibition capability was also found at 2.5% of added rosemary extract, and the oil retained 88.2% DHA and 88.3% EPA. However, only 18.8% DHA and 23.6% EPA were retained in the fish oil mixed with 5% of oregano extract and no DHA and EPA were detected in the fish oil without extract after 5-d incubation at 60 °C. Thus, antioxidant activity of the rosemary extract was greater than that of oregano extract, but was sensitive to heat. The rosemary extract also demonstrated higher DPPH (2,2'-diphenyl-1-picrylhydrazyl) free radical scavenging capability, which was approximately 3 times higher than oregano extract, although there was no significant difference in the total phenolic contents between both extracts.     

Subacute oral toxicity study of benzyl isothiocyanate in rats

The subacute toxicity of benzyl isothiocyanate (BITC) was investigated in male rats given oral doses of 0, 50, 100 and 200 mg/kg body weight/day for 4 weeks. Body weight gain and food consumption were decreased with increasing doses of BITC. Haematological changes of toxicological relevance were observed in the highest dose group. BITC administration resulted in increased serum cholesterol level in all treatment groups and decreased serum triglycerides level at 200 mg/kg. Renal dysfunction was indicated by reduced urine volume, proteinuria and enhanced urinary lactate dehydrogenase activity. BITC exposure also affected the weights of various organs and caused histological changes in the ductus choledochus, liver, ileum and mesenteric lymph nodes.     

Radiation-induced enhancement of antioxidant activity in extracts of rosemary (Rosmarinus officinalis L.)

Dry rosemary leaf powder was subjected to 30 kGy of gamma ray irradiation, followed by solvent extraction with methanol, ethanol or water. The antioxidant activity of the extracts was assessed using the DPPH radical-scavenging method and the reducing power test. EC₅₀ values, using the radical-scavenging method, indicate a 22% increase in the antioxidant activity of ethanol and water extracts as a result of irradiation treatment. EC₅₀ values in the reducing power test show an increase of 45% and 28% for the ethanol and water extracts, respectively. The antioxidant activity of methanol extracts of irradiated rosemary remained the same as in the controls in both types of test. A high correlation was found between the EC₅₀ values obtained in the DPPH radical test and those from the reducing power test. Total phenolic content (Folin–Denis test) increased by 35% in the water extracts as a result of irradiation but remained the same in the methanol and ethanol extracts. The methanol extract showed the highest antioxidant activity and the highest amount of total phenolic compounds. Radiation reduced the good correlation between antioxidant activity and total phenolic content.     

Subacute oral toxicity study of benzyl isothiocyanate in rats.

The subacute toxicity of benzyl isothiocyanate (BITC) was investigated in male rats given oral doses of 0, 50, 100 and 200 mg/kg body weight/day for 4 weeks. Body weight gain and food consumption were decreased with increasing doses of BITC. Haematological changes of toxicological relevance were observed in the highest dose group. BITC administration resulted in increased serum cholesterol level in all treatment groups and decreased serum triglycerides level at 200 mg/kg. Renal dysfunction was indicated by reduced urine volume, proteinuria and enhanced urinary lactate dehydrogenase activity. BITC exposure also affected the weights of various organs and caused histological changes in the ductus choledochus, liver, ileum and mesenteric lymph nodes.     

In vitro antioxidant analysis of supercritical fluid extracts from rosemary (Rosmarinus officinalis L.)

Different supercritical fluid extraction conditions were tested on rosemary leaves using a pilot-plant-scale extractor. Each of them provided two separated fractions which were characterized chemically by liquid chromatography–diode-array detection–mass spectrometry using electrospray in the positive mode. Twelve compounds were identified, including phenolic diterpenes and flavonoids. Owing to the lack of available standards, only carnosic acid could be quantified. The antioxidant activity of the extracts was determined by the 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) test and the -carotene bleaching test was used to study the differences in behavior of antioxidants in an emulsified medium for some of the extracts obtained. The results of the correlation studies to examine the relationship between the antioxidant activity (EC₅₀), obtained by using the DPPH test, and the concentration of all the compounds detected in the extracts showed that carnosic acid was the more correlated compound, with a coefficient of correlation of –0.87. Using forward stepwise multiple linear regression, carnosic acid, methyl carnosate and carnosol were the compounds selected to predict the mentioned activity, with a value of 0.95 for the coefficient of determination.Área de Tecnología de Alimentos, Facultad de Ciencias, Universidad Autónoma de Madrid is an associated unit of IFI-CSIC.     

Effects of blackcurrant seeds and rosemary extracts on oxidative stability of bulk and emulsified lipid substrates

The effects of blackcurrant seeds extract and commercially available rosemary extracts on rapeseed oil and rapeseed oil triacylglycerol oxidative stability were evaluated. The antioxidant activity of plant extracts was investigated, both in bulk and emulsified lipid substrates, and compared with those of α-tocopherol and BHT. The investigation showed that blackcurrant seeds and rosemary extracts are the source of active antioxidants and are appropriate for food lipid stabilization. The extracts performed better in stripped substrates as they may interfere with native tocopherols present in rapeseed oil and show different activity according to the presence of water. α-Tocopherol, a 200 ppm, was inactive in bulk and emulsified rapeseed oil but was an effective antioxidant in triacylglycerols. BHT showed the best performance of all used additives in emulsified substrates.     

迷迭香提取物对大黄鱼货架期的影响

研究了迷迭香提取物作为生物保鲜剂对大黄鱼4℃贮藏过程中其品质变化和货架期的影响。实验将碎冰处死的整条大黄鱼分别置于4℃的迷迭香溶液（0、0.1%、0.2%、0.3%）中浸泡60min,沥干后所有样品采用蒸煮袋包装于4℃的冰箱中贮藏。通过测定鱼体贮藏过程中的菌落总数、pH、TVB-N、TBA、K值、感官评分等鲜度指标的变化规律,探讨了迷迭香提取物对大黄鱼低温贮藏过程中货架期的影响。结果表明,经过迷迭香提取物处理的大黄鱼细菌总数、TVB-N、TBA、K值在储藏期20d内显著低于对照组（p<0.05）,且具有较好的感官评分;其中迷迭香浓度为0.2%时,保鲜效果最佳,能够抑制大黄鱼低温贮藏过程中的微生物繁殖,有效减缓蛋白质的降解及脂肪的氧化,有效延长大黄鱼的货架期。      

Antioxidant properties of tuna-skin and bovine-hide gelatin films induced by the addition of oregano and rosemary extracts

We have investigated the antioxidant properties (FRAP ferric-reducing ability and ABTS radical-scavenging capacity) as well as the light barrier properties of gelatin-based edible films containing oregano or rosemary aqueous extracts. For comparative purposes both bovine-hide and tuna-skin gelatins were studied. The oregano and rosemary extracts were first characterised by both their total phenolic content and antioxidant activity, with the oregano extract showing the higher values. HPLC and confocal laser scanning microscopy revealed qualitative differences between extracts although rosmarinic acid was the most abundant phenolic compound in both. After determining the total quantities of phenolics on films, the polyphenol–protein interaction was found to be more extensive when tuna-skin gelatin was employed. However, this did not clearly affect the antioxidant properties of the films, although it could affect the phenol diffusion from film to food. The light barrier properties were improved by the addition of oregano or rosemary extracts, irrespective of the type of gelatin employed.