Search Results (83)

Tianshanhong (TSH), black tea products originating from the Ningde Tianshan Mountain, has gained significant recognition in the market. However, the chemical characteristics contributing to the flavor of TSH have not yet been reported. To systematically investigate the non-volatile and volatile compounds in TSH, four grades of TSH were evaluated using national standard sensory methods, revealing that overall quality improved with higher grades. Based on the detection of ultra-performance liquid chromatography–mass spectrometry (UPLC-MS), the content of ester-type catechins was relatively high and decreased with lower grades. A total of 19 amino acids (AAs) were clustered, among them, three amino acids, L-Theanine (L-Thea), Arg, and GABA, showed highly significant correlations with the refreshing taste of TSH. Notably, the content of Arg had the highest correlation with TSH grade, with a coefficient of 0.976 (p < 0.01). According to gas chromatography mass spectrometry (GC-MS) analysis, a total of 861 kinds of volatile compounds were detected, with 282 identified and aroma-active compounds across grades selected using the PLS model. Methyl salicylate and geraniol were particularly notable, showing strong correlations with TSH grades at 0.975 and 0.987 (p < 0.01), respectively. Our findings show that non-volatile and volatile compounds can rationally grade TSH and help understand its flavor quality. Full article

Sleep is crucial to overall health and plays a significant role in skin function. While the circadian rhythm has been extensively researched for its impact on the body’s optimal functioning, the skin also possesses an independent circadian system that serves many important functions. Sleep disruptions or deprivation can significantly affect skin conditions, by compromising the skin barrier and impairing processes such as collagen production, cellular repair, and wound healing. Given the commonality of sleep disturbances, it is crucial to understand the connection between sleep, circadian regulation, and skin health. This is particularly important in understudied populations, such as those with occupational sleep disruption and individuals with hormone-related conditions like PCOS and menopause. Bidirectional relationships have been established between sleep and several inflammatory skin conditions, including atopic dermatitis, psoriasis, rosacea, and hidradenitis suppurativa. While acne is influenced by sleep, the reverse relationship, how acne affects sleep quality, has not been well established. Chronic sleep disruption can increase cortisol levels and oxidative stress, both of which contribute to skin aging and the progression of autoimmune skin conditions, including systemic lupus erythematosus. As sleep is a modifiable risk factor, it is crucial to consider therapeutic options and interventions to prevent or alleviate skin conditions. This review discusses various therapeutic approaches, including melatonin, L-Theanine, Magnesium-L-threonate, Inositol, Cinnamomi cortex, nervous system regulation, and proper sleep hygiene. These therapeutic options have been studied for their impact on sleep, and importantly, several have been evaluated for their utility as adjuncts for treating skin conditions. Overall, the relationship between sleep and skin health is clear, and incorporating sleep-focused therapeutic interventions offers potential to improve both sleep quality and skin health in individuals with a variety of skin conditions. Full article

Stress is a major factor that threatens the body’s homeostasis or well-being. Excessive stress causes psychological anxiety and tension, which disrupts the balance of the autonomic nervous system that maintains the body’s balance, resulting in hormonal imbalance and brain changes. In this study, we investigated the effects of Withania somnifera (Ashwagandha) extract on depression, neurobehavior, and hippocampal changes in model mice exposed to stress. Using an excessive restraint stress-induced depression model, we measured the behavioral changes and the levels of brain-derived neurotrophic factor (BDNF) and antioxidant genes in five groups: control, stress, low-dose W. somniferous extract (20 mg/kg/day), high-dose W. somniferous extract (40 mg/kg/day), and L-theanine (50 mg/kg/day, positive control). Stressed mice showed poorer performance in the open field and elevated plus maze tests compared with the control group. The impaired performance was restored following W. somniferous extract administration. In addition, W. somniferous extract restored the decreased expression of BDNF in the hippocampus caused by restraint stress, improved the balance of stress hormones (i.e., cortisol, dopamine, and norepinephrine), and also regulated BDNF, inflammatory genes, and antioxidant genes in brain tissue. Therefore, W. somniferous extract can induce antidepressant and anti-stress effects by maintaining brain BDNF expression and preventing hippocampal tissue alterations caused by restraint stress. Full article

Soil salinization poses a significant threat to tea plant (Camellia sinensis) production by compromising its bioactive compounds, such as polyphenols, L-theanine, and caffeine, which are key contributors to the plant’s health benefits and economic value. This study investigates the Salt Overly Sensitive 1 (SOS1) gene family, a critical salt-tolerance regulator in tea plants, to elucidate its role in maintaining quality under environmental stress. Genome-wide analysis identified 51 CsSOS1 genes, with phylogenetic and synteny analyses revealing strong evolutionary conservation with Populus trichocarpa and Arabidopsis thaliana. Promoter analysis detected stress- and hormone-responsive cis-elements, indicating adaptive functions in abiotic stress. Expression profiling demonstrated tissue-specific patterns, highlighting significant upregulation of CsSOS1-15 and CsSOS1-41 under salt and drought stress. Co-expression network analysis further linked CsSOS1 genes to carbohydrate metabolism, implicating their roles in stress resilience and secondary metabolite synthesis. Our findings provide molecular insights into CsSOS1-mediated salt tolerance, proposing potential targets for preserving bioactive compounds. This work facilitates developing salt-resistant tea plant cultivars to ensure sustainable production and quality stability amid environmental challenges. Full article

Background/Objectives: Mood disorders include symptoms of depression, anxiety, and or stress, and have increased in prevalence. Green tea and its bioactive components (epigallocatechin gallate [EGCG] and L-theanine) have been investigated for their health benefits and neuroprotective properties. As adults seek integrative and alternative treatment modalities, it is relevant to determine the effects of natural and non-pharmacological treatments on humans. This study aimed to assess current evidence from published randomized controlled trials testing the effects of green tea, green tea extracts, or its bioactive compounds on mood disorder symptomology and brain-derived neurotrophic factor (BDNF). Methods: We searched PubMed, Cochrane Library, PsycINFO, Embase, Google Scholar, and ClinicalTrials.gov, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist and utilizing predetermined inclusion and exclusion criteria. Results: A total of 445 studies were identified, 395 screened, and thirteen met inclusion criteria. Seven used one of the bioactive compounds found in green tea for intervention, while six used green tea extract, matcha, or traditional green tea. Mood disturbance was assessed with several tools, with studies reporting improvements in depressive (n = 4), anxiety (n = 6), stress (n = 5), and sleep (n = 1) symptoms. No studies found a statistically significant effect of green tea or its bioactive compounds on BDNF. Conclusions: Our findings suggest green tea, GTE, L-theanine, and EGCG may improve mood disorder symptomology, particularly symptoms of depression; no evidence to date reports effects on BDNF. Full article

This study aimed to determine the caffeine and L-theanine contents in tea infusions prepared under varying fermentation degrees, brewing conditions (temperature and time), and serving methods (tea bag/loose-leaf). Infusions of six tea types (green, white, yellow, oolong, black, and Pu-erh) and various serving forms of green, white, and black tea were brewed at 80 °C and 100 °C for 2, 5, and 10 min. Contents were analyzed using reversed-phase high-performance liquid chromatography. Caffeine levels were highest in black and yellow tea (14 ± 1.0 mg/200 mL and 13.8 ± 0.2 mg/200 mL, respectively), both of which were significantly higher than the levels in green, white, and oolong tea (11 ± 2.1 mg/200 mL; 5.8 ± 0.7 mg/200 mL; and 4 ± 1.6 mg/200 mL, respectively; p < 0.001), whereas Pu-erh tea (13 ± 2.9 mg/200 mL) had caffeine levels comparable to that of black tea (p > 0.05). L-Theanine levels were highest in black and green tea (12.3 ± 2.8 mg/200 mL and 12.5 ± 2.5 mg/200 mL, respectively), and these levels were significantly higher than those in the other tea types (p < 0.001). Brewing temperature only affected caffeine levels n, whereas L-oolong tea (4.4 → 13.5 mg/200 mL, p < 0.05); theanine remained stable (p > 0.05). Longer brewing times significantly raised both components (e.g., yellow tea caffeine levels rose to 53 ± 16.9 mg/200 mL at 10 min; p < 0.05). In black tea, cup-sized bags yielded higher caffeine levels (39 ± 9.9 mg/200 mL) than loose-leaf (24 ± 7.2 mg/200 mL) and teapot bags (p < 0.001). Serving method had no effect on green and white teas (p > 0.05). In conclusion, fermentation rate, brewing conditions, and serving method were found to influence the caffeine and L-theanine levels of tea infusions. Full article

Tea plant [Camellia sinensis (L.) O. Kuntze] is an economically important evergreen crop cultivated worldwide. While most tea plants have green leaves, albino cultivars with yellow or white young leaves have attracted growing interest due to their elevated levels of L-theanine, a key compound that enhances the umami flavor and overall quality of green tea. In this study, we characterized the morphological and biochemical traits of a novel albino tea cultivar, ‘Geumda’, developed in Korea. ‘Geumda’ exhibited yellow young shoots during the first flush and smaller leaves compared to the green-leaf standard cultivar, ‘Sangmok’. Although the catechin content of ‘Geumda’ was lower than that of ‘Sangmok’, it exhibited significantly higher levels of total amino acids, L-theanine, and arginine by 2.1-, 2.0-, and 9.8-fold, respectively. Transmission electron microscopy and gene expression analysis revealed that the elevated amino acid content in ‘Geumda’ was associated with impaired chloroplast development, leading to reduced chlorophyll content and diminished photosynthetic capacity. These findings suggest that ‘Geumda’, with its high concentrations of theanine and arginine and its impaired chloroplast development, represents a valuable genetic resource for the production of functional green teas enriched in umami flavor and beneficial health properties. Full article

Background: Chronic alcohol intake impairs intestinal function, while L-theanine (LTA) may support intestinal health. However, the protective effects of LTA to chronic alcoholic intestinal injuries remain unclear. Methods: SD rats were administered LTA for 8 weeks and then co-administered Lieber–DeCarli liquid alcohol feed and LTA for 4 weeks to establish a chronic alcoholic intestinal injury model and investigate the mitigating influence of LTA on chronic alcoholic intestinal injury. Results: LTA alleviated duodenal pathology and intestinal permeability injury and reduced intestinal oxidative stress and inflammatory response, thereby mitigating chronic alcoholic intestinal injury. Additionally, LTA ameliorated disturbances in the gut microbiota induced by chronic alcohol intake by increasing the beneficial bacteria abundance (Ruminococcus and Odoribacter) and decreasing the harmful bacteria abundance (Enterococcus). Moreover, LTA altered the metabolic profiles associated with ethanol and linoleic (LA) and arachidonic acid (AA) metabolism. ADH6, ALDH2, and ACSS1 mRNA and protein levels were upregulated by LTA, whereas those for CYP2E1, FADS2, ALOX-5, and COX-1 were downregulated. Concurrently, LTA increased the levels of metabolites, such as acetyl-CoA, and decreased the levels of ethanol, acetaldehyde, acetic acid, LA, AA, PGE2, 13-HPODE, and LTB4. Conclusions: L-theanine mitigates chronic alcoholic intestinal injury by regulating intestinal alcohol and LA-AA metabolism. Our findings support the functional potential of the dietary supplement LTA and highlight its potential for addressing chronic intestinal injury caused by chronic alcohol intake. Full article

Mineral nutrition is of vital importance in plant growth and secondary metabolites accumulation, and thereby in the nutritional value of plants. In Lonicera japonica, a preference to nitrate (NO₃⁻−N) in comparison to ammonium (NH₄⁺−N) was found in our previous study, which can be revealed from the rapid growth rate of L. japonica under NO₃⁻−N. This study assessed whether a preference for nitrogen sources could invoke metabolic reprogramming and interrelationships between factors. NO₃⁻−fed plants exhibited substantial enhancement of carbon stimulation, which was strongly and positively correlated with mesophyll conductance. As a result, the elevated carbon flux by NO₃⁻ supplement was shuttled to phenolic metabolites synthesis, including flavones and caffeoylquinic acids compounds. Notably, the stimulation was triggered by changes in the NO₃⁻ and C/N ratio and was mediated by the induction of several enzymes in the phenylpropanoid pathway. On the contrary, NH₄⁺ plants showed an increment in the content of nitrogen, carbohydrates, and amino acids (mainly a strong increase in citrulline and theanine). Within secondary metabolism, NH₄⁺ may involve active lignin metabolism, showing a dramatic increment in hydroxy−ferulic acid and lignin content. This work provides significant insights regarding the mechanisms of L. japonica in response to diverse nitrogen regimes and effective strategies of nitrogen fertilizer input for L. japonica. Full article

The jasmonic acid (JA) signaling pathway has been demonstrated to play a crucial role in plant defense against herbivorous insects. However, the relationship between Ectropis obliqua-induced defensive metabolites and the JA signaling pathway in tea plants remains poorly understood. In this study, we investigated seven key special metabolites, including p-coumaroylputrescine, feruloylputrescine, prunin, naringenin, and three monolignols, to address this knowledge gap. Epicatechin was selected as a positive control based on its well-documented regulation through the JA signaling pathway. Notably, the content of all selected compounds was significantly increased by E. obliqua infestation. Furthermore, exogenous application of high-dose methyl jasmonate (MeJA) induced the accumulation of six of the eight compounds, excluding p-coumaryl alcohol and sinapyl alcohol, whereas low-dose MeJA failed to elicit their accumulation. To confirm the results, we screened two bioactive molecules, D-allose and L-theanine, which significantly increased the endogenous JA levels at low concentrations. Interestingly, neither D-allose nor L-theanine triggered the biosynthesis of these defensive compounds. Additionally, D-allose-treated tea leaves had no significant effect on the performance of E. obliqua larvae. These findings demonstrate that the metabolic accumulation induced by E. obliqua is mediated through a high-threshold JA signaling cascade. This study provides novel insights into the relationship between plant resistance and JA signaling pathway, advancing our understanding of special metabolites mediated plant-insect interactions. Full article

Objective: This review aims to assess the efficacy and safety of different supplements, such as L-theanine, caffeine, Ginkgo biloba L., and Bacopa monnieri for improving ADHD symptoms, to determine the most effective supplement and provide insight for medical practice. Methods: International databases (PubMed/MEDLINE and Scopus) were searched for English-language RCTs, open-label studies, and cross-sectional studies. Results: Studies on L-theanine, caffeine, Ginkgo biloba L., and Bacopa monnieri have shown various effects on ADHD symptoms. L-theanine improved sleep efficiency but not other sleep parameters. Caffeine showed no significant benefits, although its combination with L-theanine may enhance attention. Bacopa monnieri consistently improved inattention, hyperactivity, and memory, whereas Ginkgo biloba L. reduced ADHD symptoms, particularly inattention, but was less effective than methylphenidate. Conclusions: The evidence revealed the potential use of supplements as complementary ADHD treatments under clinical guidance. The limited effect of supplements cannot replace the well-documented efficacy of stimulants for ADHD treatment. Additional studies are needed to ascertain the most effective dosages and the safety of these supplements as adjunctive treatments for ADHD. Full article

L-Theanine, a natural amino acid found in green tea (Camellia sinensis) leaves, is known for its diverse psychotropic effects. This study aimed to evaluate the inhibitory effect of L-theanine on melanin production and uncover its regulatory mechanism. We evaluated the anti-melanogenic activities of L-theanine in vitro and in vivo. In B16F10 murine melanoma cells induced by α-melanocyte-stimulating hormone, melanin content and intracellular tyrosinase activity were determined, and melanogenesis-related protein expression and signaling pathways were analyzed by Western blotting. Melanin reduction was further assessed using the zebrafish (Danio rerio) test. L-Theanine reduced the intracellular tyrosinase activity and melanin content of B16F10 cells. It also attenuated the expression of melanogenesis-related proteins, such as microphthalmia- associated transcription factor, tyrosinase (TYR), TYR-related protein-1, and dopachrome tautomerase. L-Theanine modulated the protein kinase A (PKA), cAMP responder element binding protein (CREB), phosphorylation of/protein kinase B (Akt), glycogen synthase kinase-3β (GSK-3β), and β-catenin. The antimelanogenic activity of L-theanine (<2 mg/mL) was further confirmed using zebrafish larvae. L-Theanine inhibited melanogenesis by downregulating the PKA/CREB and Akt/GSK-3β/β-catenin signaling pathways. In summary, L-theanine shows potential as a skin-whitening compound, warranting further investigation for its possible applications in cosmetic and pharmaceutical products. Full article

Background/Objectives: Acute alcohol consumption can cause intestinal dysfunction, whereas L-theanine (LTA) has shown the potential to support intestinal health. We explored L-theanine’s ability to protect against acute alcohol-induced injury. Methods: Male C57BL/6 mice were administered LTA for 28 d and then underwent acute alcohol intestinal injury modeling for 8 days. Results: The results revealed that LTA ameliorated alcohol-induced pathological damage in the duodenum and gut permeability, improved secretory immunoglobulin A (SIgA) content, and reduced oxidative stress, inflammatory markers, and serum lipopolysaccharide (LPS) content in mice. Furthermore, LTA restored the composition of the intestinal flora, increasing the abundance of Alloprevotella, Candidatus_Saccharimonas, Muribaculum, and Prevotellaceae_UCG-001. Additionally, LTA increased beneficial metabolites, such as oxyglutaric acid and L-ascorbic acid, in the HIF-1 pathway within the enrichment pathway. Further investigation into the HIF-1 signaling pathway identified up-regulation of claudin-1, HIF-1α, occludin, and ZO-1, and down-regulation of TLR4, PHD2, p65 NF-κB, TNF-α, and IFN-γ mRNA and protein levels. Conclusions: These results suggest that LTA may enhance the intestinal barrier by activating the HIF-1 signaling pathway to regulate the TLR4/NF-κB/HIF-1α axis, thereby reducing acute alcoholic intestinal injury. Full article

Wilson’s disease (WD) is an inherited disorder characterized by abnormal copper metabolism with complex pathological features. Currently, the mechanism of copper overload-induced hepatic injury is unclear. Green tea is a natural chelator, and its main ingredients, green tea polyphenol (GTP) and L-theanine (L-TA) are good at binding to heavy metals like iron and copper. There have been no reports on green tea extracts (GTE) for the treatment of Wilson’s disease. This study investigated the hepatoprotective effect of GTE on WD model mice. Initially, we examined the impact of green tea extract on copper metabolism, excretion, and hepatoprotective effects in WD model toxic milk mice. Then, Ultra performance liquid chromatography (UPLC-DAD) was established to analyze GTP and L-TA in green tea extract. Further screening of eight active components and copper complex active components in green tea extract was carried out by ion analyzer. Finally, we verified the pharmacodynamic effects of these active ingredients at the animal level. The results showed that GTE improves liver function and attenuates liver injury in TX mice by promoting tissue copper excretion and inhibiting oxidative stress, which provides a theoretical basis for green tea’s potential to improve the clinical symptoms of WD. Full article

L-theanine, a unique non-protein amino acid predominantly found in tea plants (Camellia sinensis), plays a pivotal role in plant responses to abiotic stress and significantly influences tea quality. In this review, the metabolism and transport mechanisms of L-theanine are comprehensively discussed, highlighting its spatial distribution in tea plants, where it is most abundant in young leaves and less so in roots, stems, and older leaves. The biosynthesis of L-theanine occurs through the enzymatic conversion of glutamate and ethylamine, catalyzed by theanine synthase, primarily in the roots, from where it is transported to aerial parts of the plant for further catabolism. Environmental factors such as temperature, light, drought, elevated CO₂, nutrient unavailability, and heavy metals significantly affect theanine biosynthesis and hydrolysis, with plant hormones and transcription factors playing crucial regulatory roles. Furthermore, it has been demonstrated that applying L-theanine exogenously improves other crops’ resistance to a range of abiotic stresses, suggesting its potential utility in improving crop resilience amid climate change. This review aims to elucidate the physiological mechanisms and biological functions of L-theanine metabolism under stress conditions, providing a theoretical foundation for enhancing tea quality and stress resistance in tea cultivation. Full article