Potent antimutagenic activity of white tea in comparison with green tea in the Salmonella assay

l-theanine: From tea leaf to trending supplement - does the science match the hype for brain health and relaxation?

l-Theanine is a unique non-protein amino acid found abundantly in tea leaves. Interest in its potential use as a dietary supplement has surged recently, especially claims related to promoting relaxation and cognitive enhancement. This review surveys the chemistry, metabolism, and purported biological activities of l-theanine. It is well absorbed from the intestine and can cross the blood-brain barrier. Some studies suggest l-theanine may increase alpha waves in the brain associated with relaxation and selective attention, reduce stress and anxiety, and improve sleep quality, though findings are often inconsistent. Potential neuroprotective and anti-seizure effects have also been reported in animal models. When combined with caffeine, l-theanine may improve cognitive performance, alertness and focus. However, the evidence supporting many health claims remains limited, especially the lack of rigorous human clinical trials. While l-theanine exhibits a good safety profile based on toxicology studies, caution is warranted regarding the purported health benefits, until stronger scientific substantiation emerges. Overall, the mechanisms of action and therapeutic potential of l-theanine require further investigation, given the current interest and increasing popularity of this nutraceutical supplement marketed for brain health and relaxation. In the absence of well-designed and carefully controlled human clinical trials, we would urge caution in the use of l-theanine supplements at pharmacologic doses by the wider population, and believe that the science does not yet match the hype behind this trending supplement for brain health and relaxation.

UV-C light-activated gallic acid and non-thermal technologies for inactivating Salmonella Typhimurium inoculated in aqueous solution and whole cow milk

This study aimed to evaluate the effect of UV-C light-activated gallic acid (GA) alone and combined with ultrasound (US) or ultraviolet-C light (UV-C, 254 nm) on the inactivation of Salmonella Typhimurium in aqueous solution for being later applied to whole cow milk. First-order, Weibull, and Beta models were used to describe the inactivation kinetics of S. Typhimurium by GA alone and combined with non-thermal technologies. Results indicated that GA concentration, the UV-C light activation process, and the combination of US and UV-C light significantly affected (p < 0.05) the inactivation of S. Typhimurium in aqueous solution, which was properly described by the first order (R2 > 0.84), Weibull (R2 > 0.96), and Beta (R2 > 0.83) models. The activation process of GA increased its antimicrobial activity in the range of 40.87-101.44 %. Moreover, with the highest concentration of GA and the application of US or UV-C light, >5 log reductions were achieved. Nevertheless, although these combinations were applied to whole cow milk, a low reduction (2.0-log cycles) was obtained, regardless of the GA activation and non-thermal technologies. Therefore, the effect of GA, whether UV-C light activated or not, on S. Typhimurium depends on the food matrix. This highlights that in whole cow milk, this treatment was insufficient to ensure safety, even when combined with non-thermal technologies. INDUSTRIAL RELEVANCE: UV-C light and US are non-thermal technologies used as alternatives to thermal treatments. These technologies can be used on their own or in combination; however, in many cases, the necessary microbial reduction is not attained, thus the use of complementary techniques or processes is required. GA is a phenolic compound with low antimicrobial activity; however, UV-C light may activate its antimicrobial activity. In this sense, this study shows the potential application of GA and non-thermal technologies for inactivating S. Typhimurium in an aqueous solution and the first approach of this methodology in whole cow milk as a liquid food product.

In vitro genotoxicity assessment of biosynthesized zinc oxide nanoparticles

There are various studies on the toxicological potentials of conventionally synthesized zinc oxide (ZnO) nanoparticles, which are useful tools for many medical applications. However, knowledge about the biologically synthesized ones is still limited. In this study, the potential of producing ZnO nanoparticles via a green synthesis method, which enables safer, environmentally, economical and controlled production by using the Symphoricarpos albus L. plant, was investigated. For this purpose, aqueous extract was obtained from the fruits of the plant and reacted with zinc nitrate precursor. Characterization of the synthesized product was carried out by SEM and EDAX analyzes. In addition, the biosafety of the product was also investigated by using the Ames/Salmonella, E. coli WP2, Yeast DEL, seed germination, and RAPD test systems. The results obtained from SEM studies showed that spherical nanoparticles with an average diameter of 30 nm were synthesized as a result of the reaction. EDAX findings confirmed that these nanoparticles were composed of Zn and O elements. On the other hand, according to the findings of the biocompatibility tests, the synthesized nanoparticle did not show any toxic and genotoxic effects up to a concentration of 640 μg/ml in any of the test systems. Accordingly, considering the findings of our study, it was concluded that the aqueous extract of S. albus fruits can be used for the green synthesis of ZnO nanoparticles, the products obtained successfully passed the biocompatibility tests in our study, and additionally, more comprehensive biocompatibility tests should be performed before industrial scale production.

Chemical Composition, Antioxidant and Antimicrobial Effects of Essential Oils Extracted from Two New Ocimum basilicum L. Varieties

Recent agricultural research aims to identify novel applications for plant extracts as efficient defenses against weeds, insects, or phytopathogenic agents. The main goal of the present study was to evaluate two new varieties of basil (Ocimum basilicum L., fam. Lamiaceae), Yellow basil, “Aromat de Buzau” variety and Red-violet basil, “Serafim” variety. The basil varieties were studied under different aspects regarding biochemical characterization using GC-MS, antioxidant activity evaluated under three methods (DPPH, ABTS, FRAP), and antimicrobial properties (for three G-bacteria: Perctobacterium carotovorum, Pseudomonas marginalis, Pseudomonas syringae and three phytopathogenic fungi: Rhizoctonia solani, Fusarium oxysporum, Botrytis cinerea). The results showed that linalool (39.28%; 55.51%), estragole (31.48%; 9.78%), and eugenol (5.42%; 7.63%) are the main compounds identified in the extracts, validating the high antioxidant activity of the studied essential oils and floral waters. When applied in high concentrations, essential oils have shown a potential bactericidal effect on P. carotovorum as well as a potential fungicidal effect on R. solani and B. cinerea.

Essential Oils as Multicomponent Mixtures and Their Potential for Human Health and Well-Being

Essential oils (EOs) and their individual volatile organic constituents have been an inherent part of our civilization for thousands of years. They are widely used as fragrances in perfumes and cosmetics and contribute to a healthy diet, but also act as active ingredients of pharmaceutical products. Their antibacterial, antiviral, and anti-inflammatory properties have qualified EOs early on for both, the causal and symptomatic therapy of a number of diseases, but also for prevention. Obtained from natural, mostly plant materials, EOs constitute a typical example of a multicomponent mixture (more than one constituent substances, MOCS) with up to several hundreds of individual compounds, which in a sophisticated composition make up the property of a particular complete EO. The integrative use of EOs as MOCS will play a major role in human and veterinary medicine now and in the future and is already widely used in some cases, e.g., in aromatherapy for the treatment of psychosomatic complaints, for inhalation in the treatment of respiratory diseases, or topically administered to manage adverse skin diseases. The diversity of molecules with different functionalities exhibits a broad range of multiple physical and chemical properties, which are the base of their multi-target activity as opposed to single isolated compounds. Whether and how such a broad-spectrum effect is reflected in natural mixtures and which kind of pharmacological potential they provide will be considered in the context of ONE Health in more detail in this review.

Comparative study of phenolic profile, antioxidant and antimicrobial activities of aqueous extract of white and green tea

The sole difference between white tea (WT) and green tea (GT) is the former that made only from the buds and young leaves of the Camelia sinensis plant, whilst the latter is made from matured tea leaves. The phytochemical profiles, phenolic compounds, antioxidant, and antimicrobial activity of two varieties of Camellia sinensis teas, white and green, were compared in this study. Total antioxidant capacity, reducing power, DPPH radical scavenging, and Fe+2 chelating activities were used to determine antioxidant activities in water extract of GT and WT. The largest level of phenolic content was discovered in WGTE compared with the lowest amount was found in WWTE (290.67 mg/100 g tea and 185.96 mg/100 g tea, respectively). Phenoilc acids (gallic, benzoic, chlorogenic, ellagic, and ρ-coumaric acids) and flavonoids (rutin and kampherol) were found in the two extracts. The findings of DPPH radical scavenging assays were 84.06 and 82.37% inhibition. In vitro antimicrobial activity was indicated that (WWTE and WGTE) had a high level of activity against Staphylococcus aureus, and gave negative activity against Salmonella typhimurium, and Aspergillus Niger. The WT and GT extracts are a great source of natural antioxidants with biological effects on human health.

Lethal concentrations of Cymbopogon nardus essential oils and their main component citronellal on Varroa destructor and Apis mellifera

Varroosis is a disease caused by the mite Varroa destructor, and it is considered one of the biggest threats to honey bee populations globally. Mite control is centered on the use of synthetic acaricides, such as amitraz and flumethrine. However, high usage of these chemicals is associated with a wide variety of undesirable effects on bee colonies, including the development of resistance and persistence of harmful residues of acaricides in hive products used by humans. Botanical extracts have been identified as a potentially suitable organic alternative to synthetic acaricides. Essential oils, such as clove, eucalyptus, lemongrass, and oregano, have been found to exhibit acaricidal activity against V. destructor. The main goal of this work was to assess the bioactivity of the Cymbopogon nardus essential oil from two different locations (Argentina and India), and the activity of its major component the monoterpene citronellal. According to our results, complete essential oil from India is more effective in controlling parasitosis than the isolated citronellal component. The essential oil of C. nardus from Argentina demonstrated promise for the control of varroosis, as well as exhibiting low toxicity against bees (LC₅₀ = 11.84 μL/mL). In addition, this essential oil may avoid the problems caused by synthetic acaricides, such as the emergence of resistance foci in Varroa and residues in hive products. Future research needs to investigate the delivery of volatile essentials oils to target mite populations.

Identification of the age of white tea using proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) coupled with multivariate analysis

RATIONALE

In recent years, white tea has become increasingly popular. Some merchants confuse the age of white tea and sell poor-quality products for profit. Therefore, it is necessary to provide technical support for product authentication and valorization in white tea of different marked ages.

METHODS

Volatile organic compounds (VOCs) were detected by proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) and identified as volatile fingerprints. PTR-TOF-MS combined with multivariate analysis was found to identify white tea of four different marked ages (1, 3, 5, and 8 years) for authentication. Principal component analysis (PCA) and orthogonal partial least-squares discriminant analysis (OPLS-DA) were used as classification models to identify key volatile metabolites.

RESULTS

The OPLS-DA model achieved the best results (96.67%, 96.67%, 96.67%, and 96.67% in the training set and 96.00%, 96.00%, 100%, and 100% in the prediction set for 1-year, 3-year, 5-year, and 8-year tea samples, respectively), showing that PTR-TOF-MS with the OPLS-DA model could successfully be used in the identification of white tea with different marked ages. Out of the 60 identified VOCs, 26 volatile materials were closely correlated with tea age and were used as markers to discriminate white tea of different ages.

CONCLUSIONS

PTR-TOF-MS coupled with multivariate analysis could be applied for quality evaluation of tea products of different ages and provided a feasible technical support for product authentication and valorization in white tea of different marked ages.

Tea and coffee polyphenols and their biological properties based on the latest in vitro investigations

Tea and coffee contain numerous polyphenolic compounds that exhibit health-promoting properties for humans, including antioxidant and neuroprotective properties, and can also take part in the treatment of covid-19 and improve fertility. This review, presents the activity of polyphenols found in different types of tea and coffee and describes the effects of tea fermentation and coffee roasting on their polyphenol composition and antioxidant properties. Polyphenol oxidase activity is reduced in the fermentation process; therefore black tea contains significantly less polyphenolic compounds compared to green and white tea. Epigallocatechin-3-gallate - a polyphenol from tea - effectively has been shown to inhibit the activity of SARS-CoV-2 as it blocked binding of coronavirus 2 to human angiotensin converting enzyme 2, decreased the expression of inflammatory factors in the blood, including tumor necrosis factor-α and interleukin-6, and significantly increased the overall fertilization efficiency in animals. Coffee roasting process influences both the content of polyphenols and the oxidative activity. The lowest levels of active compounds such as caffeine, chlorogenic acid and coffee acids are identified in roasted coffee beans. On the other hand, light coffee and green coffee show the strongest cytotoxic potential and antioxidant properties, and thus the greatest ability to decrease apoptosis by stopping the cell cycle in the S phase. Proteins, such as components of milk, can strongly bind/interact with phenolic compounds (especially, the CGAs) contain in coffee, which may explain the negative influence of milk on its antioxidant properties. Coffee polyphenols have also antiproliferative and antiesterase activities, which may be important in prevention of cancer and neurodegenerative disorders, respectively. In this review, biological properties of tea and coffee polyphenols, observed mainly in in vitro studies have been described. Based on these findings, future directions of the research works on these compounds have been suggested.

Tea and coffee polyphenols and their biological properties based on the latest in vitro investigations

Tea and coffee contain numerous polyphenolic compounds that exhibit health-promoting properties for humans, including antioxidant and neuroprotective properties, and can also take part in the treatment of covid-19 and improve fertility. This review, presents the activity of polyphenols found in different types of tea and coffee and describes the effects of tea fermentation and coffee roasting on their polyphenol composition and antioxidant properties. Polyphenol oxidase activity is reduced in the fermentation process; therefore black tea contains significantly less polyphenolic compounds compared to green and white tea. Epigallocatechin-3-gallate - a polyphenol from tea - effectively has been shown to inhibit the activity of SARS-CoV-2 as it blocked binding of coronavirus 2 to human angiotensin converting enzyme 2, decreased the expression of inflammatory factors in the blood, including tumor necrosis factor-α and interleukin-6, and significantly increased the overall fertilization efficiency in animals. Coffee roasting process influences both the content of polyphenols and the oxidative activity. The lowest levels of active compounds such as caffeine, chlorogenic acid and coffee acids are identified in roasted coffee beans. On the other hand, light coffee and green coffee show the strongest cytotoxic potential and antioxidant properties, and thus the greatest ability to decrease apoptosis by stopping the cell cycle in the S phase. Proteins, such as components of milk, can strongly bind/interact with phenolic compounds (especially, the CGAs) contain in coffee, which may explain the negative influence of milk on its antioxidant properties. Coffee polyphenols have also antiproliferative and antiesterase activities, which may be important in prevention of cancer and neurodegenerative disorders, respectively. In this review, biological properties of tea and coffee polyphenols, observed mainly in in vitro studies have been described. Based on these findings, future directions of the research works on these compounds have been suggested.

Widely Targeted Metabolomics Analysis Reveals Great Changes in Nonvolatile Metabolites of Oolong Teas during Long-Term Storage

As a semifermented tea, oolong is exceedingly popular worldwide for its elegant, flowery aroma and mellow, rich taste. However, recent marketing trends for old oolong teas and their chemical quality largely remain unexplored. In this study, we applied widely targeted metabolomics using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) combined with multivariate analysis to investigate the chemical change of oolong teas in the aging process. With the increasing of store time, most nongalloylated catechins; tannins, including TFs and proanthocyanidins; flavonols and glycosylated flavonols; amino acids and their derivatives; nucleotides and their derivatives; and lots of alkaloids and phospholipids declined, while most fatty acids and organic acids increased, and galloylated catechins, GA, and caffeine were almost stable. The result also suggested that approximately seven years (but not an infinite extension) was a special period for oolong tea storage, which brings about excellent taste.

Forecast of ameliorating effect of dietary flavonol consumption in white tea with or without aerobic training on type 2 diabetes (T2D) in females

BACKGROUND AND AIMS

Diabetes Mellitus (D.M.) is a chronic metabolic disease characterized by hyperglycemia due to insufficient or inefficient insulin secretory response that has become a widespread epidemic primarily due to the increasing prevalence and incidence of type 2 diabetes. Phytochemicals such as flavonoids and regular physical activity have recently attracted attention to developing new anti-diabetic drugs or alternative therapy to control diabetes. The aim of this study was to compare effects of dietary Flavonol consumption in white tea, with or without aerobic training, among patients with type 2 diabetes mellitus as a randomized trial.

METHODS

49 women with T2D were randomly assigned into groups including control, white tea, aerobic training, and aerobic training + white tea. The interventions were carried out for six months. Weight, Body Mass Index (BMI), body Fat, peak oxygen consumption (VO2_Max), and Blood Pressure were evaluated at both the first and last days of the research period. Blood samples were withdrawn on the same days via venipuncture to test blood glucose, insulin, low-density lipoprotein (LDL), high-density lipoprotein (HDL), cholesterol, and triglycerides (T.G.).

RESULTS

Characteristics analysis showed significant improvements in treated groups. In addition, glucose, insulin, LDL, Cholesterol, and T.G. were significantly reduced while HDL was remarkably increased in treated groups compared to pre-experiment values or the diabetic control group.

CONCLUSION

Collectively, white tea combined with aerobic training favorably affects glycemic parameters, lipid profile, blood pressure, and VO2_Max in six months in women with T2D. Registered under Clinical Trials.gov Identifier no. NCT00123456.

Macro-composition quantification combined with metabolomics analysis uncovered key dynamic chemical changes of aging white tea

It is a common belief in China that aging could improve the quality of white tea. However, the stored-induced compositional changes remain elusive. In this study, ten subsets of white tea samples, which had been stored for 1-, 2-, 3-, 4-, 5-, 6-, 7-, 10-, 11- and 13- years, were selected. Macro-compositions were quantified firstly. As the results showed, it was interesting to find total flavonoids, thearubigins (TRs), and theabrownines (TBs) increasing, accompanied with a gradual decrease of total polyphenols, which suggest a conversion of phenolic component in the aging process. Then, nontargeted metabolomics was further conducted on selected subsets of samples, including 1-, 7- and 13- years stored to profile their conversion. As a result, most different metabolites were related to flavonol glycosides and flavone glycosides, suggesting dynamic phenolic component changes were vital in aging. The partial least-squares-discriminant analysis (PLS-DA) also identified them as markers in distinguishing.

Tea polyphenols and Levofloxacin alleviate the lung injury of hepatopulmonary syndrome in common bile duct ligation rats through Endotoxin -TNF signaling

BACKGROUND & AIMS

Hepatopulmonary syndrome (HPS) is characterized by pulmonary vasodilation and arterial blood oxygen desaturation in patients with chronic liver disease. Generally, common bile duct ligation (CBDL) rats are a suitable experimental model for studying hepatopulmonary syndrome. Our previous study demonstrated that endotoxin surges markedly, followed by bacterial translocation and the loss of liver immune function in all the stages of CBDL, thereby contributing to the pathogenesis of HPS. However, the mechanisms behind the increase of the endotoxin and how to alleviate it have not yet been elucidated. Pulmonary injury induced by increased bilirubin, endotoxin, and inflammatory mediators occurs in the early and later stages of CBDL. This study assessed the effects of Tea polyphenols (TP) and Levofloxacin on endotoxin reduction and suppression of lung injury in HPS rats in the long and short term, respectively.

METHODS

Morphological change of pulmonary injury, HPS relative index, endotoxin concentration, and the activation extent of Malondialdehyde (MDA) and Myeloperoxidase (MPO) were evaluated in CBDL rats with or without TP and Levofloxacin for three weeks or six weeks. The inflammation factors of serum, lung tissue, and BALF were then compared at the same condition for the two time periods. This was followed by adoption of the network pharmacology approach, which was mainly composed of active component gathering, target prediction, HPS gene collection, network analysis, and gene enrichment analysis. Finally, the mRNA and protein levels of the inflammatory factors were studied and relative signaling expression was assessed using RT-PCR and Western blot analysis.

RESULTS

The obtained results indicated that the pulmonary injury manifestation was perceived and endotoxin, MDA, and MPO activation were markedly increased in the early and later stages of CBDL. TP and Levofloxacin treatment alleviated endotoxin infection and inflammation factor expression three weeks and six weeks after CBDL. In addition, Levofloxacin displayed a short time anti-bacterial effect, while TP exerted a long period function. TP and Levofloxacin also reduced TNF-α, TGF-β, IL-1β, PDGF-BB, NO, ICAM-1, and ET-1 expression on the mRNA or protein expression. With regard to the pharmacological mechanism, the network analysis indicated that 12 targets might be the therapeutic targets of TP and Levofloxacin on HPS, namely ET-1, NOs3, VEGFa, CCl2, TNF, Ptgs2, Hmox1, Alb, Ace, Cav1, and Mmp9. The gene enrichment analysis implied that TP and Levofloxacin probably benefited patients with HPS by modulating pathways associated with the AGE-RAGE signaling pathway, the TNF signaling pathway, the HIF-1 signaling pathway, the VEGF signaling pathway, and the IL-17 signaling pathway, Rheumatoid arthritis, Fluid shear stress, and atherosclerosis. Finally, the TNF-α level was mainly diminished on the protein level following CBDL.

CONCLUSIONS

TP and Levofloxacin could alleviate pulmonary injury for short and long period, respectively, while at the same time preventing endotoxin and the development of HPS in CBDL rats. These effects are possibly associated with the regulation of the Endotoxin -TNF-α pathways.

White Tip Silver Needle (Slightly Fermented White Tea) Flavonoids Help Prevent Aging via Antioxidative and Anti-Inflammatory Effects

AIM

White tip silver needle, a slightly fermented white tea, is abundant in flavonoids, and it has great significance in terms of D-galactose/lipopolysaccharide-induced aging in mice.

METHODS

We analyzed the antioxidant capacity of white tip silver needle flavonoids (WTSNF) in vitro, assessed the effects of WTSNF on organ indexes, pathological changes, liver function indexes, biochemical indicators, molecular biological indicators, and genes related to oxidation and inflammation.

RESULTS

Ultra-high performance liquid chromatography-tandem mass spectrometry results showed that WTSNF contained baicalin, kaempferol, kaempferide, quercetin, isorhamnetin, lespenephryl, and rutin. WTSNF showed strong scavenging ability for both 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) free radicals. Pathological analysis results showed that WTSNF reduced liver, kidney, and lung damage in mice with induced aging. In the serum and liver tissue, WTSNF effectively increased the antioxidant-related levels of superoxide dismutase, catalase, glutathione peroxidase, glutathione, and total antioxidant capacity and reduced the levels of aspartate aminotransferase, alanine aminotransferase, malondialdehyde and nitric oxide. WTSNF also reduced the inflammation-related levels of interleukin-6, interleukin-1 beta, tumor necrosis factor alpha (TNFα), and interferon gamma (IFN-γ) and increased the levels of interleukin-10 and interleukin-12. Furthermore, WTSNF upregulated the mRNA expression levels of cupro-zinc superoxide dismutase, manganese superoxide dismutase, catalase, glutathione peroxidase, interleukin-10, neuronal nitric oxide synthase, endothelial nitric oxide synthase, nuclear factor erythroid 2-related factor, heme oxygenase 1, NAD(P)H dehydrogenase [quinone] 1, nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκB-α), and thioredoxin, while it downregulated the mRNA expression levels of interleukin-6, interleukin-18, interleukin-1 beta, TNFα, IFN-γ, inducible nitric oxide synthase, cyclooxygenase-2, and nuclear factor kappa-light chain-enhancer of activated B cells (NF-κB).

CONCLUSION

WTSNF is a high-quality natural product with antioxidative and anti-inflammatory properties that can inhibits D-galactose/lipopolysaccharide-induced aging in mice.

Comparative characteristics of white and black ceylon tea based on morphological features of the leaf

The central question of the research was addressed to comparative characteristics of white and black Ceylon tea based on morphological features of the leaf. The relevance of the study is due significant increasing falsifications of black and white tea on markets in Russia and all around the world. It should be noted that tea is still incomplete and insufficiently studied crop, despite its centuries-old use in human nutrition. Thus, the purpose of this work was to study the microstructure of black and white tea to identify differences in morphological characteristics of the leaf and develop markers for identifying its variety. The objects of study of this work were white and black varieties OP1 teas of Nandana Tea Factory (Sri Lanka). In our research were used research methods includes organoleptic and microscopical methods. According to the results micro- and macroscopic studies of black and white tea samples showed that there are significant morphological differences in the structure of leaves of different varieties, such as the size and density of hairs, the density of stomata, the location of druses and sclereids, and outgrowths of the leaf edge. These signs can serve as reliable markers for identifying the grade of tea.

Essential Oils as Alternative Biocides for the Preservation of Waterlogged Archaeological Wood

Waterlogged archaeological wood is exposed to a high risk of biological degradation during the post-excavation phases of storage and restoration. For this reason, often biocides must be used to preserve wooden remains. In the present work three essential oils (cinnamon, wild thyme, and common thyme) were tested as possible alternative biocides to use in the preservation of waterlogged archaeological wood. The oils were first tested in vitro to establish the minimum inhibitory concentration (MIC) and to evaluate the biocidal activity on selected fungal strains. Then, the established MIC was applied on waterlogged archaeological wood samples and during an actual restoration treatment. The effectiveness of the oils was evaluated through cultural analyses, ATP quantification, and next-generation sequencing. The results showed that the oils caused a significant decrease in the vitality of fungal mycelia grown in vitro and of the microbiota present in treated wood and storage water. Furthermore, an influence on the composition of the bacterial communities of treated wood samples was observed. Although further tests are needed to evaluate interferences with the materials used during restoration procedures, essential oils could be considered as a possible alternative to the currently used biocide.

Intranasal administration of white tea alleviates the olfactory function deficit induced by chronic unpredictable mild stress

CONTEXT

White tea [Camellia sinensis (L) O.Ktze. (Theaceae)] is popular in Asia, but its benefits on olfactory injury are unknown.

OBJECTIVE

The present study explores the effects of white tea on the olfactory injury caused by chronic unpredictable mild stress (CUMS).

MATERIALS AND METHODS

C57BL/6J mice (WT) were exposed to CUMS. CUMS mice (CU) were intranasally treated with white tea extract [low tea (LT), 20 mg/kg; high tea (HT), 40 mg/kg] and fluoxetine (CF, 20 mg/kg) for 7 days. Several behavioural tests were conducted to assess depression and olfactory function. The transmission electron microscope (TEM) and semi-quantitative reverse transcription PCR were performed separately to observe the changes of related structures and genes transcription level.

RESULTS

The depressive behaviours of the LT and HT mice were reversed. The latency time of the buried food pellet test decreased from 280 s (CU) to 130 s (HT), while the olfactory sensitivity and olfactory avoidance test showed that the olfactory behaviours disorder of LT and HT mice were alleviated. The white tea increased the A_490 nm values of the cortisol treated cells from 0.15 to 1.4. Reduced mitochondrial and synaptic damage in the olfactory bulb (OB), enhanced expression of the brain-derived neurotrophic factor (BDNF) and olfactory marker protein (OMP) were observed in the LT and HT mice.

CONCLUSIONS AND DISCUSSION

White tea has the potential in curing the olfactory deficiency related to chronic stress. It lays the foundation for the development of new and reliable drug to improve olfactory.

Essential oils as additives in active food packaging

Food packaging can be considered as a passive barrier that protects food from environmental factors such as ultraviolet light, oxygen, water vapour, pressure and heat. It also prolongs the shelf-life of food by protecting from chemical and microbiological contaminants and enables foods to be transported and stored safely. Active packaging (AP) provides the opportunity for interaction between the external environment and food, resulting in extended shelf-life of food. Chemoactive packaging has an impact on the chemical composition of the food product. The application of natural additive such as essential oils in active packaging can be used in the forms of films and coatings. It has been observed that, AP helps to maintain temperature, moisture level and microbial and quality control of the food. This review article provides an overview of the active packaging incorporated with essential oils, concerns and challenges in industry, and the effect of essential oil on the packaging microstructure, antioxidant and antimicrobial properties.

Hepatoprotective effect of Raspberry ketone and white tea against acrylamide-induced toxicity in rats

The current investigation was accomplished to evaluate the hepatoprotective effect of White tea and Raspberry Ketone against toxicity induced by acrylamide in rats. Sixty adult male rats were divided randomly into group (I) control; group (II) rats received RK with dose (6 mg/kg/day); Group III: rats received 5 ml of WT extract/kg/day; Group IV rats received AA (5 mg/kg/day); Group V: rats administrated with both AA (5 mg/kg/day) and RK (6 mg/kg/day) and Group VI: rats administrated AA (5 mg/kg/day) and 5 ml of WT extract/kg/day. The biochemical assays exhibited a significant increase in serum levels of Adiponectin, AST, ALT, ALP of the group treated with acrylamide if compared to the control group and an improvement in their levels of groups V and VI. The histopathological and immunohistochemical findings confirm the biochemical observations. In conclusion, the present investigation proved that the supplementation of WT and RK enhanced the liver histology, immunohistochemistry and biochemistry against the oxidative stress induced by acrylamide.

White Peony (Fermented Camellia sinensis) Polyphenols Help Prevent Alcoholic Liver Injury via Antioxidation

White peony is a type of white tea (Camellia sinensis) rich in polyphenols. In this study, polyphenols were extracted from white peony. In vitro experiments showed that white peony polyphenols (WPPs) possess strong free radical scavenging capabilities toward 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). Long-term alcohol gavage was used to induce alcoholic liver injury in mice, and relevant indices of liver injury were examined. WPPs effectively reduced the liver indices of mice with liver injury. The serum levels of aspartate aminotransferase (ATS), alanine aminotransferase (ALT), alkaline phosphatase (ALP), triglycerides (TG), total cholesterol (TC), blood urea nitrogen (BUN), nitric oxide (NO), and malondialdehyde (MDA) were downregulated, while those of albumin (ALB), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were upregulated. WPPs also reduced the serum levels of interluekin-6 (IL-6), interluekin-12 (IL-12), tumor necrosis factor-alpha (TNF-α), and interferon-gamma (IFN-γ) in mice with liver injury. Pathology results showed that WPPs reduced alcohol-induced liver cell damage. Quantitative polymerase chain reaction (qPCR) and western blot results revealed that WPPs upregulated the mRNA and protein expressions of neuronal nitric oxide synthase (nNOS), endothelial nitric oxide synthase (eNOS), manganese superoxide dismutase (Mn-SOD), cupro–zinc superoxide dismutase (Cu/Zn-SOD), and CAT and downregulated iNOS expression in the liver of mice with liver injury. WPPs protected against alcoholic liver injury, and this effect was equivalent to that of silymarin. High-performance liquid chromatography revealed that WPPs mainly contained the polyphenols gallic acid, catechinic acid, and hyperoside, which are critical for exerting preventive effects against alcoholic liver injury. Thus, WPPs are high-quality natural products with liver protective effects.

A Comparative Study of Antioxidant Potential and Phenolic Content in White (Silver Needle), Green and Black Tea

Background:

White, green and black are the major tea types obtained from the same tea plant (Camellia sinensis). The differences in processing result in different types of tea, of which green tea (20%) and black tea (78%) are the most consumed worldwide and also white tea is gaining popularity due to its subtle taste and recent evidences about its health benefits. Silver needle is a sub type of white tea, made purely from buds whereas green tea is procured from leaves that are steamed or panfried, and to produce black tea, the tea leaves are withered, fully oxidized and then dried.

Objective:

The present study was undertaken to analyze and compare the antioxidant activity and phenolic composition of white (silver needle), green and black teas of same brand.

Method:

The radical scavenging ability of different tea types was measured using various antioxidant assays. The total phenolic content was also estimated using Folin-Ciocalteu’s method.

Results:

The white tea (silver needle) demonstrated highest radical scavenging activity followed by green and then black tea in various antioxidant assays performed. The total phenolic content of different types of tea exhibited the following order: white tea (133.30mg/g) > green tea (118.37mg/g) > black tea (101.8mg/g). A strong correlation was observed between the total phenolic content and antioxidant activity of different tea types, the correlation coefficient ranged from 0.87-0.97.

Conclusion:

White tea (silver needle) manifested highest antioxidant activity followed by green and least in black tea. The pronounced antioxidant ability of WT (silver needle) may be ascribed to the different parts of the plant (unopened buds) and the least processing it undergoes, followed by obtaining green tea and black tea from different parts of the plant (leaves), and variation in degree of processing.

Effect of storage time on antioxidant activity and inhibition on α-Amylase and α-Glucosidase of white tea

White tea is considered as a special kind of tea not only for its simplest process, but also for its endurable storage. However, little studies have been done about the changes of white tea with increasing aging time, including its composition and health‐imparting effects. In the present work, white tea aged 1 year (WT‐1), 3 years (WT‐3), and 5 years (WT‐5) were collected. Their major chemical compounds, antioxidant activities, and inhibitory effects on α‐Amylase and α‐Glucosidase were evaluated. Results showed that white tea of different storage time showed good antioxidant activity in DPPH, ABTS, and FRAP assay, which decreases with the prolongation of storage time. The inhibitory effects on α‐Amylase and α‐Glucosidase which are key enzymes related to type II diabetes in vitro, are also observed in the similar trend. Meanwhile, prolongation of storage time decreased the content of polyphenols, the main bioactive compounds in tea, which may lead to decrease in the activities investigated.

Identification and comparison of oligopeptides during withering process of White tea by ultra-high pressure liquid chromatography coupled with quadrupole-orbitrap ultra-high resolution mass spectrometry

Peptides could have specific tastes or bioactivities depending on the length and sequence of amino acids. Till date it remains unknown what peptides are formed during the white tea manufacturing process and whether they contribute to the flavor or bio-activities of white tea. As a first step to address these questions, we applied ultra-high pressure liquid chromatography coupled with quadrupole-orbitrap ultra-high resolution mass spectrometry (UPLC-Quadrupole-Orbitrap-UHRMS) to monitor peptides dynamic changes during the withering process. A total of 196 abundant peptides were identified. Most of them were oligopeptides within a molecular weight of 1000 Da. Four of them were randomly selected, synthesized peptides were applied for further confirmation and quantification. Sequence analysis suggested that some of them were potential taste contributors. Proteinase cleave site analysis identified two separate periods of active proteins degradation at 0-12 h and 30-42 h of the withering processes. Further analysis of cleavage sites also suggested that protein degradation during withering steps were random rather than a stepwise reaction.

Non-targeted metabolomics reveals distinct chemical compositions among different grades of Bai Mudan white tea

So far, the chemical quality of different grades of white tea has largely remained unexplored. The objective of this study was to establish a model for quality evaluation of different grades of Bai Mudan white tea. We applied non-targeted ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry in combination with multivariate analysis and analyzed four different grades of Bai Mudan white tea. We found that the metabolite composition from the super-grade and the first-grade shared higher similarity compared to the second-grade or the third-grade white tea, and the Partial Least Square-Discriminant Analysis model showed high capability to explain the sample variation (R2Y = 0.998, Q2 = 0.95 in negative ionization modes). In total, 93 metabolites were structurally identified, wherein 21 low abundant metabolites showed distinct changes in abundance that were closely correlated with tea grade variation. These findings suggested their potential as markers to discriminate different grades of Bai Mudan white tea.

Novel Flavoalkaloids from White Tea with Inhibitory Activity against the Formation of Advanced Glycation End Products

Two novel flavoalkaloids, (-)-6-(5'''- S)- N-ethyl-2-pyrrolidinone-epigallocatechin- O-gallate (ester-type catechin pyrrolidinone A, etc-pyrrolidinone A, 1), (-)-6-(5'''- R)- N-ethyl-2-pyrrolidinone-epigallocatechin- O-gallate (etc-pyrrolidinone B, 2), and new naturally occurring flavoalkaloids, (-)-8- N-ethyl-2-pyrrolidinone-epigallocatechin- O-gallate (etc-pyrrolidinone C, 3a, and etc- pyrrolidinone D, 3b), were isolated from white tea ( Camellia sinensis). Their structures were identified by extensive nuclear magnetic resonance spectra. The absolute configuration of compounds 1 and 2 was decided by comprehensive circular dichroism spectroscopic analyses. The isolated flavoalkaloids together with (-)-epigallocatechin- O-gallate (EGCG) were evaluated for their inhibition against the formation of advanced glycation end products, with IC₅₀ values ranging from 10.3 to 25.3 μM. Ultra performance liquid chromatography coupled with diode array detection and electrospray ionization mass spectrometry detected these flavoalkaloids in both white tea and fresh tea leaves, which demonstrated the existence of a corresponding biosynthetic pathway in tea plants. Therefore, a possible pathway was proposed to involve deamination, decarboxylation, and spontaneously cyclization of l-theanine and then attachment of the product to EGCG to form the flavoalkaloids.

Anticancer Properties of Essential Oils and Other Natural Products

Essential oils are secondary metabolites with a key-role in plants protection, consisting primarily of terpenes with a volatile nature and a diverse array of chemical structures. Essential oils exhibit a wide range of bioactivities, especially antimicrobial activity, and have long been utilized for treating various human ailments and diseases. Cancer cell prevention and cytotoxicity are exhibited through a wide range of mechanisms of action, with more recent research focusing on synergistic and antagonistic activity between specific essential oils major and minor components. Essential oils have been shown to possess cancer cell targeting activity and are able to increase the efficacy of commonly used chemotherapy drugs including paclitaxel and docetaxel, having also shown proimmune functions when administered to the cancer patient. The present review represents a state-of-the-art review of the research behind the application of EOs as anticancer agents both in vitro and in vivo. Cancer cell target specificity and the use of EOs in combination with conventional chemotherapeutic strategies are also explored.

Antioxidant Activity of Different Forms of Green Tea: Loose Leaf, Bagged and Matcha

Green tea is commercially available in three forms: loose leaf, bagged and powdered. The objective of this study was to compare the radical scavenging capacity of different forms of green tea like loose leaf (3), bagged (2) and powdered matcha (2) of various brands. The green tea forms were prepared at 95-100°C for 5 min., to mimic conditions usually used for tea preparations at home. The comparison of combined IC50 values of different green tea forms (loose leaf, bagged and matcha) showed no significant difference in their radical scavenging activity except bagged tea that exhibited slightly more DPPH radical scavenging potential as compared to matcha. Individually, the Bud white loose leaf demonstrated highest antioxidant activity followed by Laplant bag, Lipton bag, Laplant loose, Gourmet matcha, Wow matcha and Lipton loose. These findings revealed that on the basis of form, it may not be possible to generalize which form of tea whether loose leaf, bagged or matcha, is more effective in scavenging free radicals.

Essential oils of Varronia curassavica accessions have different activity against white spot disease in freshwater fish

The aim of this study was to evaluate the antiprotozoal activity of essential oils from Varronia curassavica accessions against different stages of Ichthyophthirius multifiliis. Essential oils from each accession were tested in vitro at the concentrations 0, 10, 25, 50, 75, 100, and 200 mg/L. The VCUR-001, VCUR-202, VCUR-509, and VCUR-601 accessions presented the major compounds α-pinene, germacrene D-4-ol, (E)-caryophyllene and epiglobulol, and sabinene, respectively. These isolated compounds were tested in vitro at a concentration proportional to that found in the essential oil which caused 100% mortality of the parasite. The concentrations of 10 and 50 mg/L of the essential oil of accession VCUR-202 provided 100% mortality of trophonts and tomonts, respectively. For the accession VCUR-509, 100% mortality of trophonts and tomonts was observed at concentrations 75 and 200 mg/L of essential oil, respectively. The same mortality was observed at concentration 200 mg/L in both stages of the parasite for the other accessions. The major compounds α-pinene, sabinene, and the (E)-caryophyllene + epiglobulol mixture caused 100% mortality of trophonts and tomonts. The in vivo assay for white spot disease control was performed in a therapeutic bath of 1 h with the essential oil of accession VCUR-202 at concentrations of 0.5 and 2.0 mg/L. A significant reduction of about 30% of trophonts on infected fish was observed, independent of the oil concentration. The V. curassavica essential oil, especially the VCUR-202 accession, is a potential source of raw material for the formulation and commercialization of bioproducts to control freshwater white spot disease in fish.

Genotoxic evaluation of newly synthesized iminothiazolidinones

The current study was designed to assess the potential toxicological effects of newly synthesized iminothiazolidinones by employing Ames Salmonella, Escherichia coli WP2, Zea mays seed germination, and random amplified polymorphic DNA (RAPD) assay systems. The bacterial tester strains S. typhimurium TA1535, TA1537, TA1538, TA98, TA100, and E. coli WP2 uvrA were chosen to test the direct gene mutation inducing capabilities of the test materials in prokaryotic systems and Z. mays seeds for determination of potential toxicological effects in eukaryotic systems. OPA-3 and OPA-6 primers were used in the RAPD analysis to determine genotoxic activities on the eukaryotic genomes. According to the results, none of the test materials showed significant mutagenic activity on the bacterial tester strains at the chosen concentrations. Additionally, none of the tested compounds showed inhibition of the germination of Z. mays seeds. In contrast, the RAPD analysis results were inconsistent with the bacterial reversion assays and the seed germination assay results. All test materials significantly changed the RAPD profiles for OPA-3; however, only compound 5 showed a significant change for OPA-6 when compared with the control groups. In conclusion, the newly synthesized iminothiazolidinone derivatives (C1-C5) were determined as potentially genotoxic compounds and they should be checked with multiple toxicology test systems before further studies to determine their actual use.

Reduced Stress and Improved Sleep Quality Caused by Green Tea Are Associated with a Reduced Caffeine Content

Caffeine, one of the main components in green tea, can interfere with sleep and block the effect of theanine. Since theanine, the main amino acid in tea leaves, has significant anti-stress effects in animals and humans, we examined the effects of green tea with lowered caffeine content, i.e., low-caffeine green tea (LCGT), on stress and quality of sleep of middle-aged individuals (n = 20, mean age 51.3 ± 6.7 years) in a double-blind crossover design. Standard green tea (SGT) was used as the control. These teas (≥300 mL/day), which were eluted with room temperature water, were consumed over a period of seven days after a single washout term. The level of salivary α-amylase activity (sAA), a stress marker, was significantly lower in participants that consumed LCGT (64.7 U/mL) than in those that consumed SGT (73.9 U/mL). Sleep quality was higher in participants that consumed a larger quantity of LCGT. In addition, a self-diagnostic check for accumulated fatigue was significantly lower in those participants that consumed LCGT than SGT. These results indicate that LCGT intake can reduce stress in middle-aged individuals and improve their quality of sleep. The reduction in caffeine is suggested to be a valid reason for enhancing the anti-stress effect of green tea.

Characterization of white tea metabolome: Comparison against green and black tea by a nontargeted metabolomics approach

White tea is considered the least processed form of tea and is reported to have a series of potent bioactivities, such as antioxidant, anti-inflammatory, anti-mutagenic, and anti-cancer activities. However, the chemical composition of white tea and the dynamic changes of the metabolites during the manufacturing process are far from clear. In this study, we applied a nontargeted metabolomics approach based on ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF/MS) to comprehensively profile the characteristic metabolites of white tea. There were significant differences in the content of amino acids, catechins, dimeric catechins, flavonol and flavone glycosides, and aroma precursors in white tea compared with green and black teas that were manufactured from the same fresh tea leaves. Furthermore, the dynamic changes of the metabolites in the tea samples with various withering durations of 0, 4, 8, 12, 16, 20, 24, 28, and 36 h were also profiled. This study offers a comprehensive characterization of the metabolites and their changes in white tea.

ANTIMICROBIAL ACTIVITY OF BURSERA MORELENSIS RAMÍREZ ESSENTIAL OIL

Background:

Bursera morelensis, known as “Aceitillo”, is an endemic tree of Mexico. Infusions made from the bark of this species have been used for the treatment of skin infections and for their wound healing properties. In this work, we present the results of a phytochemical and antimicrobial investigation of the essential oil of B. morelensis.

Materials and Methods:

The essential oil was obtained by a steam distillation method and analyzed using GC-MS. The antibacterial and antifungal activities were evaluated.

Results:

GC-MS of the essential oil demonstrated the presence of 28 compounds. The principal compound of the essential oil was a-Phellandrene (32.69%). The essential oil had antibacterial activity against Gram positive and negative strains. The most sensitive strains were S. pneumoniae, V. cholerae (cc) and E. coli (MIC 0.125 mg/mL, MBC 0.25 mg/mL). The essential oil was bactericidal for V. cholera (cc). The essential oil inhibited all the filamentous fungi. F. monilifome (IC₅₀ = 2.27 mg/mL) was the most sensitive fungal strain.

Conclusions:

This work provides evidence that confirms the antimicrobial activity of the B. morelensis essential oil and this is a scientific support about of traditional uses of this species.

Healthy properties of green and white teas: an update

Green tea has been consumed for centuries in Japan, China and Morocco.

Long-term intake of white tea prevents oxidative damage caused by adriamycin in kidney of rats

BACKGROUND

White tea infusion (Camelia sinensis) has antioxidants properties. The infusion contains polyphenols that have been proposed to induce antioxidant response element (ARE) response via nuclear factor E2-related factor 2 (NRF2). Adriamycin (ADR) has antitumour properties and oxidative effects. Oxidative stress is related to a variety of kidney diseases. Prevention of the oxidative stress through long-term intake of white tea and the study of the molecular mechanisms involved in protection could be of great interest. Rats were given distilled water, 0.015 or 0.045 g of solid white tea extract kg(-1) body weight for 12 months. Animals received an injection of ADR. In kidney, oxidative stress parameters were measured, the expressions of nuclear factor E2-related factor 2 gene (Nrf2), and detoxifying and antioxidants genes were analysed, and the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione reductase (GR) were measured.

RESULTS

ADR administration increased oxidative parameters and decreased the antioxidant activity; significantly increased the expression of analysed genes and the activity of CAT and SOD and decreased GR activity. The highest white tea dose protected redox status and inhibited ARE response.

CONCLUSION

Long-term intake of white tea protected kidney against the oxidative stress. ADR activated the ARE response but in animals treated with the highest dose of white tea, this response was inhibited, probably for antioxidant protection. © 2015 Society of Chemical Industry.

Kazakh Ziziphora Species as Sources of Bioactive Substances

Ziziphora species represent the prototypical example of the Lamiaceae family. The phytochemicals present in Ziziphora include monoterpenic essential oils, triterpenes and phenolic substances belonging to the flavonoids. In Kazakh traditional medicine, Ziziphora species possess several medicinal uses. In particular, Z. bungeana Lam. and Z. clinopodioides Lam. are used for the treatment of illnesses related to the cardiovascular system or to combat different infections. Unfortunately, the majority of the information about the complex Ziziphora species is only available in Russian and Chinese language, therefore, we decided gather all available information on Kazakhstan Ziziphora, namely its content compounds, medicinal uses and published patents, to draw the attention of scientists to this very interesting plant with high medicinal potential.

Therapeutic Potential of Essential Oils Focusing on Diterpenes

Among all plant derivates, essential oils (EOs) have gained the attention of many scientists. Diterpenes, a family of components present in some EO, are becoming a milestone in the EOs world. The goal of this review is to describe a scenario of diterpenes taking into health-consumption deportment. Previous studies revealed that diterpenes have antioxidant, antimicrobial, antiviral, antiprotozoal, cytotoxic, anticancer, antigenotoxic, antimutagenic, chemopreventive, antiinflammatory, antinociceptive, immunostimulatory, organoprotective, antidiabetic, lipid-lowering, antiallergic, antiplatelet, antithrombotic, and antitoxin activities. In conclusion, diterpenes may be an immense featuring concern in pharmaceutical consumption from a drug discovery point of view. Copyright © 2016 John Wiley & Sons, Ltd.

Antioxidant, mutagenic, and antimutagenic activities of Tragopogon longirostis var. longirostis, an edible wild plant in Turkey

Objectives:

The ethanolic extract of Tragopogon longirostis var. longirostis, a wild edible plant in Anatolia was isolated, and its antioxidant, mutagenic, and antimutagenic properties were investigated.

Materials and Methods:

The antioxidant activity (AA) was determined by the inhibition of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, total AA, and phenolic compounds. The mutagenic and antimutagenic activities were investigated by Ames Salmonella/microsome mutagenicity test.

Results:

The IC₅₀ value for DPPH radicals was 7.84 ± 0.603 mg/mL. The total AA increased with an increase in the concentration of the extracts (1, 5, 10, 20, and 30 mg/mL), containing linoleic acid emulsion. The total phenolic content was 284.71 ± 5.6 mg gallic acid equivalent/g extract. The results showed that the ethanolic extract can be considered safe, because it does not have any mutagenic effect at the tested concentrations. As a result, the ethanolic extract of the leaves exhibited antimutagenic effects at 2.5, 0.25, and 0.025 mg/plate concentrations.

Conclusions:

To our knowledge, this is the first study of the antioxidant, mutagenic, and antimutagenic activities of T. longirostis var. longirostis. These activities are an important topic in the food industry, as well as in the medical field.

Nutraceuticals for body-weight management: The role of green tea catechins

Green tea catechins mixed with caffeine have been proposed as adjuvants for maintaining or enhancing energy expenditure and for increasing fat oxidation, in the context of prevention and treatment of obesity. These catechins-caffeine mixtures seem to counteract the decrease in metabolic rate that occurs during weight loss. Their effects are of particular importance during weight maintenance after weight loss. Other metabolic targets may be fat absorption and the gut microbiota composition, but these effects still need further investigation in combination with weight loss. Limitations for the effects of green tea catechins are moderating factors such as genetic predisposition related to COMT-activity, habitual caffeine intake, and ingestion combined with dietary protein. In conclusion, a mixture of green tea catechins and caffeine has a beneficial effect on body-weight management, especially by sustained energy expenditure, fat oxidation, and preservation of fat free body-mass, after energy restriction induced body-weight loss, when taking the limitations into account.

Naturally occurring bioactive compounds from four repellent essential oils against Bemisia tabaci whiteflies

BACKGROUND

In tropical countries, netting is an effective sustainable tool for protecting horticultural crops against Lepidoptera, although not against small pests such as Bemisia tabaci, while smaller mesh netting can be used in temperate regions. A solution is to combine a net with a repellent. Previously we identified repellent essential oils: lemongrass (Cymbopogon citratus), cinnamon (Cinnamomum zeylanicum), cumin (Cuminum cyminum) and citronella (Cymbopogon winternarius). The present study was designed to identify the active compounds of these essential oils, characterise their biological activity and examine their potential for coating nets. We investigated the efficiency and toxicity of nets dipped in different solutions. We then studied the repellent effect with an olfactometer and the irritant effect by videotracking.

RESULTS

Geraniol and citronellol were the most promising net coatings owing to their repellent effect. The repellency, irritancy or toxicity varied with the product and concentration, and these features were independent, indicating that the repellent and the irritant/toxic mechanisms were not the same. The combined effects of these different compounds account for the bioactivity of the mixture, suggesting interactions between the compounds.

CONCLUSION

This new sustainable strategy for protecting vegetable crops against whiteflies is discussed, in addition to the use of companion plants that could produce such bioactive compounds.