Alfreda Wei

Antioxidant/Lipoxygenase Inhibitory Activities and Chemical Compositions of Selected Essential Oils

Twenty-five essential oils were tested for antioxidant activities using a conjugated diene assay, the aldehyde/carboxylic acid assay, the DPPH free radical scavenging assay, and the malonaldehyde/gas chromatography (MA/GC) assay. They were also tested for lipoxygenase inhibitory activities using the lipoxygenase inhibitor-screening assay. Thyme oil exhibited the greatest antioxidant effect in all assays (80-100%) except in the DPPH assay (60%). Clove leaf oil showed activities comparable to those of thyme oil (53-100%). Cinnamon leaf oil showed strong activities in the aldehyde/carboxylic acid assay (100%) and DPPH assay (84%), but only moderate activities in the conjugated diene assay (24%) and MA/GC assay (48%). Basil oil exhibited a strong effect in the DPPH assay (86%) and moderate activities in the MA/GC assay (35%). Bergamot oil exhibited 100% antioxidant activity in the aldehyde/carboxylic acid assay. Eucalyptus and chamomile oils showed appreciable activities only in the conjugated diene assay. Bitter orange oil exhibited moderate antioxidant activity (53%) only in the MA/GC assay. Aloe vera oil exhibited the greatest lipoxygenase inhibitory activity (96%), followed by thyme oil (86%) and bergamot oil (85%) at a concentration of 0.5 microg/mL. Chamomile oil showed slight lipoxygenase inhibitory activity at 0.5 microg/mL but strong lipoxygenase inducing activity at 5 microg/mL (-123%). Thyme and clove leaf oils contained high levels of thymol (23%) and eugenol (77%), respectively, as a principal of the antioxidant activity. The results obtained in the present study suggest that some essential oils possess strong medicinal activities, which can be utilized for treatment of certain diseases.

Complex I-associated hydrogen peroxide production is decreased and electron transport chain enzyme activities are altered in n-3 enriched fat-1 mice.

The polyunsaturated nature of n-3 fatty acids makes them prone to oxidative damage. However, it is not clear if n-3 fatty acids are simply a passive site for oxidative attack or if they also modulate mitochondrial reactive oxygen species (ROS) production. The present study used fat-1 transgenic mice, that are capable of synthesizing n-3 fatty acids, to investigate the influence of increases in n-3 fatty acids and resultant decreases in the n-6∶n-3 ratio on liver mitochondrial H2O2 production and electron transport chain (ETC) activity. There was an increase in n-3 fatty acids and a decrease in the n-6∶n-3 ratio in liver mitochondria from the fat-1 compared to control mice. This change was largely due to alterations in the fatty acid composition of phosphatidylcholine and phosphatidylethanolamine, with only a small percentage of fatty acids in cardiolipin being altered in the fat-1 animals. The lipid changes in the fat-1 mice were associated with a decrease (p<0.05) in the activity of ETC complex I and increases (p<0.05) in the activities of complexes III and IV. Mitochondrial H2O2 production with either succinate or succinate/glutamate/malate substrates was also decreased (p<0.05) in the fat-1 mice. This change in H2O2 production was due to a decrease in ROS production from ETC complex I in the fat-1 animals. These results indicate that the fatty acid changes in fat-1 liver mitochondria may at least partially oppose oxidative stress by limiting ROS production from ETC complex I.

Effect of water content in a canned food on voluntary food intake and body weight in cats

OBJECTIVE To determine whether water content in a canned food diet induces decreases in voluntary energy intake (EI) or body weight (BW) in cats fed ad libitum. ANIMALS 16 sexually intact male domestic shorthair cats. PROCEDURES Maintenance EI was determined for 2 months in 10 weight-stable cats consuming a control diet (typical colony diet). Cats were allocated into 2 groups of equal BW and fed a canned diet (with-water [WW] diet) or a freeze-dried version of the canned diet (low-water [LW] diet) twice daily. Diets were identical in nutrient profile on a dry-matter basis. Each dietary treatment period of the crossover experiment lasted 3 weeks, with a 3-week washout period between diets. Body composition measurements were determined by use of deuterium oxide at the end of each dietary treatment. Daily food intake was measured for determination of dry-matter intake and EI. Six other cats were used in preference tests for the 3 diets. RESULTS EI was significantly decreased for the WW diet (mean ± SD, 1,053.0 ± 274.9 kJ/d), compared with EI for the LW diet (1,413.8 ± 345.8 kJ/d). Cats had a significant decrease in BW during consumption of the WW diet. Body composition was unaltered by diet. In short-term preference tests, cats ate significantly more of the WW than the LW diet. CONCLUSIONS AND CLINICAL RELEVANCE Bulk water in the WW diet stimulated decreases in EI and BW in cats. The impact of water content on energy density and food consumption may help promote weight loss in cats.

Antioxidant activities of essential oil mixtures toward skin lipid squalene oxidized by uv irradiation

Antioxidant activities of essential oil mixtures—thyme or clove leaf with cinnamon leaf, rose, or parsley seed—toward skin lipid, squalene oxidized by UV irradiation were investigated using the malonaldehyde/gas chromatography assay. At all concentrations (50, 100, or 500 μg/mL) tested, thyme oil mixed with 500 μg/mL clove oil showed over 90% inhibitory effect against malonaldehyde formation. The order of potency of all oils mixed together at 500 μg/mL was thyme/clove leaf (93%) > clove leaf/parsley seed = clove leaf /rose (87%) > thyme/parsley seed (83%) > clove leaf/cinnamon leaf (77%) > thyme/parsley seed (71%) > thyme/cinnamon leaf (7%). In comparison, the inhibitory activities of 500 μg/mL of BHT or α-tocopheroltoward malonaldehyde formation were 85% and 76%, respectively. Pro-oxidant effects were observed for some mixtures of thyme with cinnamon leaf or rose oils. The potent antioxidant effects resulting from a mixture of thyme and clove leaf oils may be due to the presence of thymol and eugenol.

Influence of a high-protein diet on energy balance in obese cats allowed ad libitum access to food.

The influence of a high-protein [HP, 47% of metabolizable energy (ME)] diet on energy balance was evaluated in obese cats allowed ad libitum access to food. Energy intake, body weight, body composition, energy expenditure, and concentrations of hormones and metabolites associated with carbohydrate and lipid metabolism (glucose, insulin, free fatty acids, triglycerides and leptin) were measured in cats after consuming either a moderate protein (MP, 27% of ME) or HP diet for 4 months. Indirect respiration calorimetry showed that resting and total energy expenditure (kJ/day) adjusted for either body weight or lean body mass was increased in cats consuming the HP in relation to MP diets. However, voluntary energy intake also was increased in the HP treatment and, thus, there was no difference in body weight between animals consuming the two diets. Body composition measurements using deuterium oxide dilution showed that dietary protein content did not alter amounts of either lean body mass or fat mass. No significant differences (p > 0.05) were observed between the two treatment groups for blood glucose, free fatty acid or leptin concentrations, although there was a trend (p = 0.054) towards an increase of serum insulin concentrations in the cats eating the HP diet. This study showed that short-term ad libitum feeding of an HP diet did not reduce food intake or promote weight loss in obese cats. However, energy expenditure was increased in the HP diet group and it is possible that this effect of HP might help promote weight loss when energy intake is restricted.

Early Effects of Neutering on Energy Expenditure in Adult Male Cats

The initial cause of post-neutering weight gain in male cats is not entirely known. There is evidence that energy intake (EI) increases rapidly post-neutering, but it is not clear if neutering also decreases energy expenditure (EE) prior to weight gain. Thus, the purpose of this study was to determine if a decrease in EE contributes to the initial shift toward positive energy balance in neutered male cats. To determine the influence of neutering on EE independent of changes in EI and body weight (BW), male cats were fed at their pre-neutering maintenance EI and EE was measured at 4 days pre-neutering, 3–4 days post-neutering, and 9 days post- neutering. Ad libitum food access was then provided for 6 months. Body composition was measured and blood samples collected for serum chemistry at pre-neutering and 7 days, 13 days and 6 months post-neutering. Total energy expenditure (TEE) adjusted for lean body mass (LBM) did not change in cats from pre-neutering to 9 days post-neutering. However, TEE adjusted for BW and resting energy expenditure adjusted for either LBM or BW showed a small, but significant (P<0.05) increase from pre-neutering to 9 days post-neutering. When allowed free choice food access, cats showed significant increases of food intake (FI) and BW. Circulating concentrations of ghrelin increased, while adiponectin levels decreased following neutering. The results of this study indicate that initial post-neutering weight gain in male cats results from increased FI and not decreased EE. Long-term control of FI should be initiated after neutering to prevent hyperphagia and weight gain in male cats.

Medicinal Activities of Essential Oils: Role in Disease Prevention

Publisher Summary Essential oils are derived from various parts of the plant, including leaves, flowers, fruits, seeds, rhizomes, roots, and bark. In the plant, these constituents serve several physiological purposes for the plant—protection from pests and microorganisms, attraction of pollinating insects or birds, providing photoprotection to the plant, and allelopathy. The complex mixtures of volatile, aromatic components are secondary plant metabolites and are usually obtained by distillation. Mild techniques such as enfleurage, expression, extraction, or fermentation are also used for the isolation of more sensitive compounds. Essential oils have traditionally been used to impart flavoring or preservative effects in foods or to instill fragrances in cosmetics and aromatherapy. Since ancient times, numerous civilizations have also valued essential oils for their therapeutic qualities in disease prevention and treatment. Current interest in essential oils arises from the various bioactive effects they display, including antioxidant anti-inflammatory, antimicrobial, antiviral, and anticarcinogenic. Demand for plant essential oils has risen as a consequence of consumers searching for cheaper, more “natural” alternatives to disease-fighting medications. In food and cosmetic applications, essential oils are considered to be biodegradable, readily available, and “less toxic” than synthetic preservative agents. This optimism has raised concerns and stimulated studies to evaluate the safety and efficacy of essential oils in various systems in order to better understand their pharmacological properties and roles in health.Publisher Summary Essential oils are derived from various parts of the plant, including leaves, flowers, fruits, seeds, rhizomes, roots, and bark. In the plant, these constituents serve several physiological purposes for the plant—protection from pests and microorganisms, attraction of pollinating insects or birds, providing photoprotection to the plant, and allelopathy. The complex mixtures of volatile, aromatic components are secondary plant metabolites and are usually obtained by distillation. Mild techniques such as enfleurage, expression, extraction, or fermentation are also used for the isolation of more sensitive compounds. Essential oils have traditionally been used to impart flavoring or preservative effects in foods or to instill fragrances in cosmetics and aromatherapy. Since ancient times, numerous civilizations have also valued essential oils for their therapeutic qualities in disease prevention and treatment. Current interest in essential oils arises from the various bioactive effects they display, including antioxidant anti-inflammatory, antimicrobial, antiviral, and anticarcinogenic. Demand for plant essential oils has risen as a consequence of consumers searching for cheaper, more “natural” alternatives to disease-fighting medications. In food and cosmetic applications, essential oils are considered to be biodegradable, readily available, and “less toxic” than synthetic preservative agents. This optimism has raised concerns and stimulated studies to evaluate the safety and efficacy of essential oils in various systems in order to better understand their pharmacological properties and roles in health.

Influence of dietary protein level on body composition and energy expenditure in calorically restricted overweight cats

High-protein (HP) diets help prevent loss of lean mass in calorie-restricted (CR) cats. However, it is not entirely known whether these diets also induce changes of energy expenditure during periods of CR. To investigate this issue, sixteen overweight cats were fed either a high-protein [(HP), 54.2% of metabolizable energy (ME)] or a moderate-protein [(MP), 31.5% of ME] diet at 70% of their maintenance energy intakes for 8 weeks, and energy expenditure, energy intake, body weight and composition, and serum metabolites and hormones were measured. While both groups of cats lost weight at a similar rate, only cats eating the HP diet maintained lean mass during weight loss. Indirect respiration calorimetry measurements revealed that both total and resting energy expenditure (kcal/d) significantly decreased during weight loss for both treatment groups. However, only cats eating the MP diet exhibited significant decreases of total and resting energy expenditures after energy expenditure was normalized for body weight or lean mass. Results from this study suggest that in addition to sparing the loss of lean mass, feeding HP diets to overweight cats in restricted amounts may be beneficial for preventing or minimizing decreases of mass-adjusted energy expenditure during weight loss.

Chapter 4 – Medicinal Activities of Essential Oils: Role in Disease Prevention

Publisher Summary Essential oils are derived from various parts of the plant, including leaves, flowers, fruits, seeds, rhizomes, roots, and bark. In the plant, these constituents serve several physiological purposes for the plant—protection from pests and microorganisms, attraction of pollinating insects or birds, providing photoprotection to the plant, and allelopathy. The complex mixtures of volatile, aromatic components are secondary plant metabolites and are usually obtained by distillation. Mild techniques such as enfleurage, expression, extraction, or fermentation are also used for the isolation of more sensitive compounds. Essential oils have traditionally been used to impart flavoring or preservative effects in foods or to instill fragrances in cosmetics and aromatherapy. Since ancient times, numerous civilizations have also valued essential oils for their therapeutic qualities in disease prevention and treatment. Current interest in essential oils arises from the various bioactive effects they display, including antioxidant anti-inflammatory, antimicrobial, antiviral, and anticarcinogenic. Demand for plant essential oils has risen as a consequence of consumers searching for cheaper, more “natural” alternatives to disease-fighting medications. In food and cosmetic applications, essential oils are considered to be biodegradable, readily available, and “less toxic” than synthetic preservative agents. This optimism has raised concerns and stimulated studies to evaluate the safety and efficacy of essential oils in various systems in order to better understand their pharmacological properties and roles in health.Publisher Summary Essential oils are derived from various parts of the plant, including leaves, flowers, fruits, seeds, rhizomes, roots, and bark. In the plant, these constituents serve several physiological purposes for the plant—protection from pests and microorganisms, attraction of pollinating insects or birds, providing photoprotection to the plant, and allelopathy. The complex mixtures of volatile, aromatic components are secondary plant metabolites and are usually obtained by distillation. Mild techniques such as enfleurage, expression, extraction, or fermentation are also used for the isolation of more sensitive compounds. Essential oils have traditionally been used to impart flavoring or preservative effects in foods or to instill fragrances in cosmetics and aromatherapy. Since ancient times, numerous civilizations have also valued essential oils for their therapeutic qualities in disease prevention and treatment. Current interest in essential oils arises from the various bioactive effects they display, including antioxidant anti-inflammatory, antimicrobial, antiviral, and anticarcinogenic. Demand for plant essential oils has risen as a consequence of consumers searching for cheaper, more “natural” alternatives to disease-fighting medications. In food and cosmetic applications, essential oils are considered to be biodegradable, readily available, and “less toxic” than synthetic preservative agents. This optimism has raised concerns and stimulated studies to evaluate the safety and efficacy of essential oils in various systems in order to better understand their pharmacological properties and roles in health.

Effects of obesity, energy restriction and neutering on the faecal microbiota of cats

Surveys report that 25-57 % of cats are overweight or obese. The most evinced cause is neutering. Weight loss often fails; thus, new strategies are needed. Obesity has been associated with altered gut bacterial populations and increases in microbial dietary energy extraction, body weight and adiposity. This study aimed to determine whether alterations in intestinal bacteria were associated with obesity, energy restriction and neutering by characterising faecal microbiota using 16S rRNA gene sequencing in eight lean intact, eight lean neutered and eight obese neutered cats before and after 6 weeks of energy restriction. Lean neutered cats had a bacterial profile similar to obese rodents and humans, with a greater abundance (P<0·05) of Firmicutes and lower abundance (P<0·05) of Bacteroidetes compared with the other groups. The greater abundance of Firmicutes in lean neutered cats was due to a bloom in Peptostreptococcaceae. Obese cats had an 18 % reduction in fat mass after energy restriction (P<0·05). Energy reduction was concurrent with significant shifts in two low-abundance bacterial genera and trends in four additional genera. The greatest change was a reduction in the Firmicutes genus, Sarcina, from 4·54 to 0·65 % abundance after energy restriction. The short duration of energy restriction may explain why few bacterial changes were observed in the obese cats. Additional work is needed to understand how neutering, obesity and weight loss are related to changes in feline microbiota and how these microbial shifts affect host physiology.