Search Results (506)

The tea tree (Melaleuca alternifolia) essential oil (TTEO) exhibited in vitro antioxidant activities with an inhibition concentration (IC50) of 29.02 ± 0.57 µg/mL. This is due to its content of bioactive compounds; practically α-pinene (1.52%), eucalyptol (9.05%), 2-bornanone (57.94%), 1-dotriacontanol (1.82%), 1-decanol, 2-hexyl- (1.99%), and 1-heptatriacotanol (4.90%). Therefore, this research aimed to determine changes in growth, antioxidant capacity, immune functions, and disease resistance in Nile tilapia (Oreochromis niloticus) when fed on a low-fishmeal (FM) diet enriched with TTEO. Nile tilapia juveniles (14.6–15.9 g) were fed on a low-FM diet containing 0.0 (the control), 0.1, 0.15, 0.2, and 0.25 g TTEO/kg feed up to apparent satiety three times a day for 70 days. Following the feeding trial, fish were intraperitoneally injected with Aeromonas hydrophila, and fish mortality was recorded for an additional 10 days. It is noted that feeding the fish on 0.2 g TTEO/kg feed increased the feed intake as well as the growth indices. Marked declines in FCR values were seen in fish fed on 0.15–0.25 g TTEO/kg feed. However, fish fed on a diet with 0.2 g TTEO/kg feed exhibited highest enhancements in intestinal villi width/length and absorption area compared with other TTEO levels. No statistical (p > 0.05) differences were observed in glucose and cortisol levels among TTEO-fed groups, indicating no stress effects on fish. Conversely, ALT and AST activities in Nile tilapia declined significantly (p < 0.05), especially at 0.20 and 0.25 g TTEO/kg feed, with no difference (p > 0.05) between the two treatments. It is noted that high TTEO levels (0.2–0.25 g/kg feed) increased hepatic superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities as well as the mRNA expression of hepatic SOD, CAT, and GPx genes. Compared with other TTEO groups, feeding the fish with 0.2 g TTEO/kg feed showed higher alkaline phosphatase, lysozyme, complement C3, and ACH50 levels, along with marked increases in IL-8 and IL-10 genes expression and declines in the expression TNF-α, IL-1ß, HSP70, Caspase-3, and Caspase-9 genes. After A. hydrophila infection, fish fed on the control diet exhibited the highest mortality (76.7%), whereas fish fed on 0.2 and 0.25 g TTEO/kg feed were more resistant to bacterial infection, with mortality rates of 23.3% and 26.7%, respectively, with no difference (p > 0.05) between them. The results confirmed that dietary TTEO enhanced growth, antioxidant capacity, immunological biomarkers, and disease resistance in Nile tilapia when added to low-FM diets, with an optimum dose of 0.2 g TTEO/kg feed. Full article

Green tea quality is largely determined by the metabolite profile of fresh leaves. However, the time-of-day-dependent dynamics of these metabolites remain largely unknown in Xinyang Maojian (XYMJ), a premium Chinese green tea. In this study, we performed the first integrative transcriptomic and metabolomic analysis of Camellia sinensis cv. Xinyang 10 shoots (one bud and one leaf) sampled at 7:00, 13:00, and 18:00 under field conditions with light intensities of 19.2, 113, and 5.4 klx, respectively. We identified 525 differentially accumulated metabolites and 19,767 differentially expressed genes exhibiting distinct time-of-day-dependent patterns. Physiological measurements confirmed significant fluctuations in starch, soluble sugars, chlorophyll, relative water content, and polyphenols throughout the daytime. A key finding was a daytime carbon allocation trade-off: primary metabolism (starch biosynthesis, glycolysis, TCA cycle) peaked at 13:00, whereas secondary metabolism (flavonoids, theaflavins, phenolic acids, anthocyanins) dominated at 18:00, supported by strong negative correlations between primary and secondary metabolic modules. Chlorophyll and oligomeric catechins peaked at 7:00; theaflavins at 13:00; and starch, soluble sugars, theanine, and organic acids at 18:00. Light-responsive transcription factors (bZIP, NF-Y, HD-Zip, SPL, ARF, MADS) and other regulators (MYB, AP2/ERF, WRKY, NAC, GRAS, bHLH) exhibited time-specific expression, sequentially modulating flavonoid, caffeine, and theanine biosynthesis, along with specific gene modules including SS3/SS4 (starch synthesis), BAM3 (starch degradation), FBA1 (carbon fixation), CYP72A219 (terpenoid metabolism), and L7A (theaflavin biosynthesis). Evening-harvested leaves accumulated higher levels of theanine (umami) and soluble sugars (sweetness), whereas morning leaves were enriched in astringent catechins and flavonols. This multi-omics dissection of time-of-day-dependent metabolism in XYMJ tea provides a scientific basis for time-of-day harvesting strategies and graded processing of tea products. Full article

Particle-containing gels were functionalized with clove, peppermint, tea tree, sage, coconut, lemon, and eucalyptus oils to obtain a novel material for dental applications with improved cell interactions and antibacterial applications. Dried samples, SEM imaging, and elemental mapping revealed a homogeneous distribution of inorganic and organic components throughout the gel matrix. EDX and XPS investigations revealed changes in elemental composition and surface chemistry following the addition of essential oil. Also, FTIR spectroscopy revealed characteristic interactions between the silica-rich network and bioactive oil constituents through slight modifications. In contrast, UV–Vis and PL investigations showed differences in the optical behavior of the formulations. TG-DTA measurements with decomposition analysis revealed a noticeable increase in essential oils, which broadly influenced the chemical composition. Biological evaluation using L929 fibroblasts demonstrated >73% cell viability after 72 h in essential oil-containing structures, confirming proper cytocompatibility. The compatibility between the silica-based formulation and essential oils resulted in better cellular effects without compromising compatibility. Therefore, the promising potential of these multifunctional formulations for advanced oral care applications has been experimentally demonstrated and reported. Full article

Aeromonas species are among the most important Gram-negative pathogens in aquaculture and represent a One Health concern, as antibiotic-resistant strains circulate at the interface between ornamental fish, the aquatic environment and humans. This study evaluated the in vitro antibacterial activity of four commercial essential oils from tea tree (Melaleuca alternifolia), peppermint (Mentha piperita), rosemary (Rosmarinus officinalis) and lavandin (Lavandula hybrida) against sixteen oxytetracycline-resistant Aeromonas hydrophila and A. veronii isolated from moribund ornamental fish. All tested bacteria were resistant to oxytetracycline (MIC 8–16 µg/mL). Minimum inhibitory (MIC) and minimum bactericidal (MBC) concentrations were determined by broth microdilution. All EOs inhibited every isolate, but their bactericidal capacity differed markedly. Rosemary oil showed the lowest MIC and MBC ranks and the most consistent values, followed by tea tree and lavandin; all three were bactericidal. Peppermint oil, despite a low MIC, showed a high MBC and was bacteriostatic. These findings indicate that the EOs of rosemary, tea tree and lavandin are promising in vitro candidates for use against oxytetracycline-resistant Aeromonas in aquaculture, in line with the One Health approach, and warrant further evaluation. Full article

Airborne fungi and bacteria pose a severe challenge for conservators, as they can settle on artistic surfaces, leading to chemical, physical and aesthetic degradation of artworks. A new air-cleaning system has been developed to reduce indoor airborne microorganisms by leveraging the antimicrobial potential of Tea Tree (Melaleuca alternifolia) Essential Oil (TTEO) encapsulated within the pores of MCM-41 mesoporous silica microparticles (MCM-TTEO), thereby extending its antimicrobial activity and enhancing its efficacy. Experimental data showed a progressive release of TTEO from the MCM-TTEO system during the 5 weeks monitoring. The release rate was quite linear in the first week, reaching about 16.2%, before plateauing at approximately 30% in the next weeks. A comparison of the performances of the MCM-TTEO system with those of the non-encapsulated (‘free’) TTEO was performed using a comprehensive air quality monitoring approach, which tracked temperature, relative humidity, microbial loads and particulate matter. Results demonstrate that the MCM-TTEO system maintained higher biocidal activity over the 5-week study period than the free EO. Furthermore, the biocidal efficacy increased when the MCM-TTEO system was used in direct contact with microorganisms. These promising findings highlight the potential for exploring different combinations of the two components in both passive and active configurations, including the development of air filtration systems. Full article

Wuyi rock tea quality in different rock zones differs significantly, and it is of great significance for the development of the rock tea industry to deeply reveal the mineral nutritional basis of its quality formation. In this study, the rhizosphere soils, root systems and leaves of tea trees from 180 tea plantations in different rock zones were collected, to explore the migration pattern of elements in the “soil and root system-leaf” of tea trees in different rock zones. The results showed that the contents of tea polyphenols, theanine, and caffeine were significantly higher in the authentic zone than in the semi-rock zone and the continent zone, with all three quality indices exhibiting a consistent decreasing trend from ZY to BY to ZC, and their mean values in ZY were approximately 1.2-fold and 1.4-fold higher than those in BY and ZC, respectively. The ability of the root system of tea trees in different rock zones to enrich Mn, P and S, their translocation from roots to leaves, and their accumulation in leaves directly affected tea quality. Using four machine learning approaches based on enrichment coefficients of key elements, the classification accuracy for the three rock zones reached 100%. The above conclusions were further verified by hydroponic experiments with Mn, P or S treatments, which confirmed that P exerted the strongest influence on tea quality, followed by S, with Mn showing the smallest effect. This study reveals the mineral nutrient basis for the formation of rock tea quality and lays an important theoretical foundation for the elemental directed regulation of Wuyi rock tea quality. Full article

High-altitude environments provide a favorable basis for tea quality formation, but suitable processing parameters for high-altitude Oolong Tea (HAOT, Camellia sinensis (L.) O. Kuntze) remain unclear. This study optimized key processing parameters for HAOT using a three-factor, three-level orthogonal design involving withering method, shaking intensity and standing time. Sensory evaluation, quantitative descriptive analysis (QDA), macro-compositions determination, headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS), multivariate statistics and correlation analysis were used to clarify quality differences and their chemical basis. Leaf anatomical observation showed that high-altitude fresh leaves had a thicker cuticle and more compact mesophyll structure, suggesting the need for targeted processing regulation. Range analysis indicated that shaking intensity had the largest R value for sensory scores, followed by withering method, whereas standing time showed a comparatively small R value. The favorable combination was combined withering, heavy shaking (6 rounds) and 60 min standing, hereafter referred to as FHM. FHM showed the highest floral and fruity aroma scores and produced a mellow, full-bodied taste with a sweet aftertaste. It also contained significantly higher flavonoid and soluble sugar levels than the other processing combinations. A total of 65 volatile organic compounds were detected, with terpenoids and esters as the dominant classes. ROAV analysis identified geraniol, linalool, β-ionone, (E)-nerolidol and benzaldehyde as representative major aroma-active compounds, while geraniol and linalool were especially prominent in FHM. Correlation analysis further linked flavonoids and soluble sugars with positive taste attributes, and linalool and geraniol with floral–fruity aroma. These results provide a practical basis for optimizing HAOT processing and improving product quality. Full article

Tea tree essential oil (TTO), extracted from Melaleuca alternifolia, is a terpene-rich botanical antimicrobial with demonstrated broad-spectrum activity against foodborne pathogens and spoilage microorganisms. Its bioactivity is principally attributed to oxygenated monoterpenes, most notably including terpinen-4-ol, γ-terpinene, and α-terpinene, whose structure–activity relationships govern interactions with microbial membranes and intracellular targets. This review provides a comprehensive, mechanistically grounded analysis of TTO as a sustainable antimicrobial platform for food preservation applications. The physicochemical determinants of TTO performance are critically assessed, encompassing chemotype-dependent compositional variability, hydrophobicity, limited aqueous solubility, and oxidative instability, with emphasis on how these properties constrain efficacy in complex food matrices. Antimicrobial mechanisms are systematically examined, including membrane permeabilization, disruption of cellular homeostasis, oxidative stress induction, and quorum-sensing interference. Focus is placed on nanostructured delivery systems, including nanoemulsions, biopolymer-based encapsulants, and hybrid nanocomposites, that improve physicochemical stability, modulate release kinetics, and potentiate antimicrobial activity. The integration of these engineered formulations into edible coatings, active packaging, and sanitation protocols across fresh produce, meat, and dairy systems is evaluated in the context of practical food safety applications. Translational limitations are addressed, including volatility, sensory incompatibility, regulatory constraints, and concentration-dependent cytotoxicity considerations. Collectively, this review positions TTO-based nanoformulations as a scientifically promising and technologically scalable approach to next-generation food preservation, while identifying critical gaps that must be resolved to support regulatory acceptance and commercial implementation. Full article

The terrain of tea gardens in Yunnan is complex, and the branches and leaves of tea trees are densely interlaced. Traditional manual picking methods are labor-intensive and inefficient, and can no longer meet the needs of modern tea industry development. To achieve automatic recognition of tea buds and leaves and accurate two-dimensional localization of picking points in complex natural environments, this study constructs a lightweight and high-precision tea bud and leaf detection and keypoint localization model, YOLOv11-pose-BEH, based on the YOLOv11-pose model. Based on the original network, this model introduces the BiFPN feature fusion module to achieve efficient bidirectional transmission of multi-scale information. The EMA (Efficient Multi-scale Attention) mechanism is integrated to form the C2PSA_EMA module, improving the effect of multi-scale feature extraction. HetConv is introduced to form the C3K2_HetConv module, enhancing the extraction of local texture and edge features. Compared with the baseline network, the improved YOLOv11-pose-BEH achieved significant improvements in both tea bud object detection and picking point localization. For the tea bud object detection task, the precision, recall, mAP0.5, and F1-score increased by 7.41, 6.39, 5.28, and 6.88 percentage points, respectively. For the picking point localization task, the precision, recall, mAP0.5, and F1-score increased by 5.86, 5.83, 4.83, and 5.85 percentage points, respectively. These results indicate that the proposed model can achieve more accurate and stable tea bud and leaf detection and two-dimensional picking point localization under complex backgrounds, providing efficient and reliable technical support for the visual perception of intelligent tea-picking robots in tea gardens. Full article

Polyvinyl alcohol (PVA)/chitosan (CS)-based films incorporated with Antrodia cinnamomea polysaccharide (ACP) and tea tree essential oil (TTEO) were developed using a solution casting method. The physicochemical, bioactive, and structural attributes, as well as the effects of these films on post-harvest ‘Yuluxiang’ pears, were assessed. The results demonstrated strong interactions among all functional components. The integration of ACP reinforced the mechanical properties of PVA/CS-based films, whereas the combined incorporation of ACP/TTEO enhanced water resistance, ultraviolet-light shielding ability, and barrier performance against oxygen and water vapor. Contact angle measurements showed that the PVA/CS/ACP/TTEO composite film exhibited superior wettability and adhesion to pear surfaces. Furthermore, the PVA/CS/ACP/TTEO composite film exhibited potent antibacterial activity, recording 99.99% inhibition against Staphylococcus aureus and 99.91% against Escherichia coli. TGA and DTG analyses suggested that ACP improved the thermal stability and restricted the film’s degradation rate. Antioxidant assays revealed that the incorporation of ACP and TTEO markedly elevated the antioxidant ability of the PVA/CS-based film. After 21 days of storage, the PVA/CS/ACP/TTEO composite film effectively maintained firmness, titratable acidity, vitamin C levels, and the activities of superoxide dismutase and catalase in post-harvest pears. Moreover, the composite film delayed fruit yellowing and oiliness, lowered the accumulation of hydrogen peroxide and malondialdehyde, and significantly reduced microbial counts (p < 0.05). This study demonstrates that the fabricated PVA/CS/ACP/TTEO composite film possesses the ability to extend the shelf life of perishable fruits under ambient storage conditions. Full article

Seasonal variation in aroma quality is critical for commercial grading of Xinyang Maojian (XYMJ) green tea, and how seasonal changes shape its volatile composition and aroma profile remains unclear. This study investigated the volatile profiles of XYMJ harvested in spring, summer, and autumn using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and odor activity value (OAV) analysis. A total of 93 volatile compounds were identified, with alkenes, alcohols, and esters being the most numerous chemical classes. Total volatile content decreased significantly seasonally (p < 0.05), being highest in spring (1716.68 μg/kg), followed by summer (1566.72 μg/kg) and autumn (1378.21 μg/kg). PCA and PLS-DA clearly distinguished seasons. Using a dual-filtering strategy (variable importance in the projection > 1.0 and p < 0.01), 14 differential volatile metabolites were identified as core seasonal markers. Geraniol, cis-jasmone, and indole were identified as key drivers of the premium floral fragrance in spring XYMJ, while cis-3-hexenyl hexanoate and linalool peaked in the summer harvest. OAV results and cross-modal sensory interaction principles suggest that the superior flavor of spring XYMJ arises from both higher aromatic intensity and an optimized aroma-taste balance. These findings provide useful insights into the seasonal variations in the metabolic and chemical profiles of XYMJ, enhancing our understanding of the biochemical markers associated with its production timeline. Full article

Essential oils (EOs) are widely investigated as multifunctional agents for cosmetic applications due to antimicrobial and antioxidant properties; however, their efficacy and safety depend on chemical composition and microbiological selectivity. This study characterized ten commercially available EOs (basil, lavender, melissa, mint, oregano, rosemary, sage, thyme, clove, tea tree) and evaluated their antistaphylococcal and antioxidant activities. Chemical composition was analyzed using GC-MS and ATR-FTIR spectroscopy, while antistaphylococcal activity was assessed against Staphylococcus spp. isolated from skin microbiota using the microbroth dilution method. Antioxidant capacity was determined by the DPPH assay. Multivariate statistical analyses were applied to explore chemical composition–activity relationships. The EOs showed distinct chemical profiles dominated by phenolic compounds (eugenol, carvacrol, thymol), oxygenated monoterpenes (linalool, menthol, 1,8-cineole), and terpenoids. Clove, oregano, and thyme EOs exhibited the strongest antistaphylococcal activity (MIC 0.5–2 mg/mL) and highest antioxidant capacity (>80%), whereas lavender, mint, and sage EOs showed weak effects. All EOs demonstrated bactericidal activity with consistent susceptibility patterns among Staphylococcus spp. PCA and FTIR confirmed an association between phenolic content and bioactivity. In conclusion, antimicrobial efficacy is primarily driven by phenolic composition, supporting targeted cosmetic use while acknowledging possible effects on skin Staphylococcus spp. populations. Full article

Acne vulgaris is a prevalent inflammatory disorder of the pilosebaceous unit involving follicular hyperkeratinization, altered sebum production, Cutibacterium acnes proliferation, microbiome imbalance, and immune activation. Although antibiotics, retinoids, benzoyl peroxide, and keratolytic agents remain central to clinical management, their long-term use may be limited by irritation, recurrence, adherence issues, and increasing antimicrobial resistance. This narrative review critically evaluates the dermatological relevance of Melaleuca alternifolia tea tree essential oil (TTEO), Mentha piperita peppermint essential oil (PPEO), and polyhydroxy acids (PHAs), as well as their incorporation into biopolymeric delivery systems for acne-oriented topical applications. Following SANRA principles, evidence from clinical, preclinical, ex vivo, and in vitro studies was synthesized, with emphasis on antimicrobial activity, inflammatory modulation, keratolytic and barrier-supportive effects, formulation stability, and release behavior. TTEO shows the strongest clinical support among the reviewed natural bioactives, including reductions in lesion counts and acne severity when applied as conventional or nanoemulsion-based formulations. PPEO is mainly supported by experimental evidence, particularly antimicrobial activity against acne-associated microorganisms, anti-inflammatory potential, and menthol-related neurocutaneous effects, whereas acne-specific clinical validation remains limited. PHAs, particularly gluconolactone, are better supported for barrier improvement, hydration, tolerability, and seboregulation than for direct acne lesion reduction. Hydrogels, electrospun nanofibers, polymeric films, nanoencapsulation systems, and controlled-release platforms may improve local retention, protect volatile or irritation-prone compounds, and modulate active release at the skin surface. However, most biopolymeric platforms still rely on early-stage or indirect dermatological evidence. Overall, biopolymeric delivery systems offer a rational formulation strategy to improve the stability, tolerability, and localized action of selected acne-relevant bioactives, but their clinical translation requires standardized composition, reproducible fabrication, skin-relevant release assays, safety assessment, and controlled human studies. Full article

The fall armyworm (Spodoptera frugiperda), a highly destructive invasive Lepidopteran pest, poses a serious threat to global agriculture, particularly maize production. Plant essential oils (EOs) represent a promising class of botanical pesticides owing to their diverse bioactivities and low environmental persistence. In this study, we evaluated the insecticidal and antifeedant activities of 40 commercially available EOs against third-instar S. frugiperda larvae. After an initial screening at 4 μL/mL, 10 EOs that caused ≥70% mortality at 72 h were selected for bioassays to estimate LC₅₀ value and chemical analysis by GC-MS. Contact toxicity assays showed that geranium EO had the highest activity (LC₅₀ = 2.105 μL/mL at 72 h), followed by cypress (2.123 μL/mL) and niaouli (2.391 μL/mL), whereas tea tree EO exhibited the lowest activity (3.592 μL/mL). Antifeedant tests revealed that clove EO caused the strongest feeding deterrence at both 24 h (antifeedant indices AFI = 72.8%) and 48 h (AFI = 63.4%), while most other EOs lost their deterrent effect within 48 h. GC-MS analysis of the 10 active EOs identified a complex mixture of monoterpenes, sesquiterpenes, and oxygenated derivatives; major constituents included D-limonene, 4-terpineol, carvacrol, caryophyllene, and longifolene. These results provide laboratory evidence that several plant EOs, particularly geranium, cypress, niaouli, and clove, possess strong insecticidal and antifeedant activities against S. frugiperda larvae, supporting their potential as eco-friendly botanical insecticides. Full article

Background: Bacterial skin infections in companion animals, particularly those involving multidrug-resistant Pseudomonas aeruginosa and methicillin-resistant Staphylococcus, pose significant therapeutic challenges due to rising resistance and biofilm formation. While Piper betle is well-recognized in human medicine, data on its efficacy against veterinary isolates—and the comparative phytochemistry and potency of its extracts versus essential oils—remains scarce. Objective: This study evaluated the antimicrobial and antibiofilm efficacy of an ethanolic P. betle leaf extract compared to a panel of representative essential oils—including P. betle leaf oil, clove, tea tree, and plai—against 73 feline and canine clinical isolates. Methods: Minimum inhibitory (MIC) and bactericidal (MBC) concentrations were determined via broth microdilution. Biofilm inhibition was assessed using crystal violet staining to determine the minimum biofilm inhibitory concentration (MBIC). Phytochemical profiles were characterized using gas chromatography–mass spectrometry (GC–MS) and liquid chromatography–quadrupole time-of-flight mass spectrometry (LC–MS/MS-QTOF). Results: P. betle leaf extract exhibited superior anti-pseudomonad activity (mean MIC: 1.5 mg/mL; MBC: 1.9 mg/mL), demonstrating significantly greater potency than the tested essential oils. Among the essential oils, clove oil was the most effective against Staphylococcus strains (mean MIC: 0.8 mg/mL; MBC: 1.2 mg/mL). Despite 74.4% of P. aeruginosa and 90.0% of Staphylococcus spp. being strong biofilm producers, the P. betle extract demonstrated the highest inhibitory potency against P. aeruginosa (MBIC: 0.7 mg/mL) and, alongside clove oil, showed superior efficacy against Staphylococcus spp. (MBICs: 0.3 and 0.7 mg/mL, respectively). GC–MS analysis identified chavibetol (confirmed via standard spiking) and hydroxychavicol as the primary extract constituents. LC–MS/MS-QTOF profiling further revealed a prominent phenolic profile, including 2,3-dihydroxybenzoic acid and 3,4-dihydroxybenzaldehyde. Comparative analysis suggests that while clove oil efficacy is primarily driven by high eugenol content, the broad-spectrum potency of the P. betle extract arises from a complex phenolic richness, specifically the synergistic presence of hydroxychavicol and chavibetol. Conclusions: These findings confirm the robust potential of P. betle extract as a promising plant-based antiseptic for managing biofilm-associated infections and mitigating antimicrobial resistance in veterinary medicine. Full article