Isolation, Purification and Tyrosinase Inhibitory Activity of Anthocyanins and Their Novel Degradation Compounds from Solanum tuberosum L.

To explore the composition of anthocyanins and expand their biological activities, anthocyanins were systematically isolated and purified from tubers of Solanum tuberosum L., and their tyrosinase inhibitory activity was investigated. In this study, two new anthocyanin degradation compounds, norpetanin (9) and 4-O-(p-coumaryl) rhamnose (10), along with 17 known anthocyanins and their derivatives, were isolated and purified from an acid-ethanolic extract of fresh purple potato tubers. Their structures were elucidated via 1D and 2D NMR and HR-ESI-MS and compared with those reported in the literature. The extracts were evaluated for anthocyanins and their derivatives using a tyrosinase inhibitor screening kit and molecular docking technology, and the results showed that petanin, norpetanin, 4-O-(p-coumaryl) rhamnose, and lyciruthephenylpropanoid D/E possessed tyrosinase inhibitory activity, with 50% inhibiting concentration (IC50) values of 122.37 ± 8.03, 115.53 ± 7.51, 335.03 ± 12.99, and 156.27 ± 11.22 µM (Mean ± SEM, n = 3), respectively. Furthermore, petanin was validated against melanogenesis in zebrafish; it was found that it could significantly inhibit melanin pigmentation (p < 0.001), and the inhibition rate of melanin was 17% compared with the normal group. This finding may provide potential treatments for diseases with abnormal melanin production, and high-quality raw materials for whitening cosmetics.

Probiotics from kefir: Evaluating their immunostimulant and antioxidant potential in the carpet shell clam (Ruditapesdecussatus).

This study aimed to investigate the impact of incorporating kefir into the diet on biometric parameters, as well as the immune and antioxidant responses of the carpet shell clam (Ruditapes decussatus) after an experimental infection by Vibrio alginolyticus. Clams were divided into a control group and a treated group. The control group was fed on spirulina (Arthrospira platensis) alone. While, the treated group was fed on spirulina supplemented with 10% dried kefir. After 21 days, clams were immersed in a suspension of V. alginolyticus 5 × 105 CFU mL -1 for 30 min. Seven days after experimental infection, survival was 100% in both groups. The obtained results showed a slight increase in weight and condition index in clams fed with kefir-supplemented diet for 21 days compared to control clams. Regarding antioxidant responses, the treated group showed higher superoxide dismutase activity compared to the control group. However, the malondialdehyde level was lower in the treated clams than in the control. In terms of immune parameters, the treated group showed slightly elevated activities of phenoloxidase, lysozyme and alkaline phosphatase, whereas a decreased lectin activity was observed compared to the control group. The obtained results suggest that kefir enhanced both the antioxidant and immune response of infected clams.

Molecular mechanisms underlying Tao-Hong-Si-Wu decoction treating hyperpigmentation based on network pharmacology, Mendelian randomization analysis, and experimental verification.

CONTEXT: Hyperpigmentation, a common skin condition marked by excessive melanin production, currently has limited effective treatment options. OBJECTIVE: This study explores the effects of Tao-Hong-Si-Wu decoction (THSWD) on hyperpigmentation and to elucidate the underlying mechanisms. MATERIALS AND METHODS: We employed network pharmacology, Mendelian randomization, and molecular docking to identify THSWD's hub targets and mechanisms against hyperpigmentation. The Cell Counting Kit-8 (CCK-8) assay determined suitable THSWD treatment concentrations for PIG1 cells. These cells were exposed to graded concentrations of THSWD-containing serum (2.5%, 5%, 10%, 15%, 20%, 30%, 40%, and 50%) and treated with α-MSH (100 nM) to induce an in vitro hyperpigmentation model. Assessments included melanin content, tyrosinase activity, and Western blotting. RESULTS: ALB, IL6, and MAPK3 emerged as primary targets, while quercetin, apigenin, and luteolin were the core active ingredients. The CCK-8 assay indicated that concentrations between 2.5% and 20% were suitable for PIG1 cells, with a 50% cytotoxicity concentration (CC50) of 32.14%. THSWD treatment significantly reduced melanin content and tyrosinase activity in α-MSH-induced PIG1 cells, along with downregulating MC1R and MITF expression. THSWD increased ALB and p-MAPK3/MAPK3 levels and decreased IL6 expression in the model cells. DISCUSSION AND CONCLUSION: THSWD mitigates hyperpigmentation by targeting ALB, IL6, and MAPK3. This study paves the way for clinical applications of THSWD as a novel treatment for hyperpigmentation and offers new targeted therapeutic strategies.

In vitro Evaluation of Skin Related Enzyme Inhibitory Effect and Emulgel Formulation Development Studies of Onobrychis Argyrea subsp. Argyrea with Phytochemical Analysis.

Species of Onobrychis have been used to treat skin disorders such as wounds and cuts in folk medicine and Onobrychis argyrea subsp. argyrea (OA) commonly known as 'silvery sainfoin', is a member of this genus. In this study, it was aimed to investigate the skin-related biological activities and phytochemical characterization of OA. Moreover, an emulgel formulation was developed from the main methanolic extract of the plant (OAM). Initially, to identifiy of the active fractions, aerial parts of the plant material was extracted with methanol and fractionated by n-hexane, chloroform, ethyl acetate and n-butanol, respectively. Antioxidant activity was determined by CUPRAC, TOAC, FRAP and DPPH assays. Thereafter, the inhibition potential of OAM, novel formulation and all fractions was measured against elastase, collagenase, tyrosinase and hyaluronidase enzymes. OAM was analyzed and characterized by LC/MS-MS. The major bioactive flavonoids which are rutin and isoquercetin were measured and compared as qualitative and quantitative via high performance thin layer chromatography (HPTLC) analysis in OAM and fractions. The results showed that extracts of OA can be a potential cosmeceutical agent for skin related problems.

Melanin Inhibitory Effect of Tuber himalayense Isolated in Incheon, Korea.

There has been a growing interest in skin beauty and antimelanogenic products. Melanogenesis is the process of melanin synthesis whereby melanocytes are activated by UV light or hormone stimulation to produce melanin. Melanogenesis is mediated by several enzymes, such as tyrosinase (TYR), microphthalmia-associated transcription factor (MITF), tyrosinase-related protein-1 (TRP-1), and TRP-2. In this study, we investigated the effect of Tuber himalayense extract on melanin synthesis in α-melanocyte-stimulating hormone (α-MSH)-treated B16F10 melanoma cells. We confirmed that T. himalayense extract was not toxic to α-MSH-treated B16F10 melanoma cells and exhibited a significant inhibitory effect on melanin synthesis at concentrations of 25, 50, and 100 µg/ml. Additionally, the T. himalayense extract inhibited melanin, TRP-1, TRP-2, tyrosinase, and MITF, which are enzymes involved in melanin synthesis, in a concentration-dependent manner. Furthermore, T. himalayense extract inhibited the mitogen-activated protein kinase (MAPK) pathways, such as extracellular signal-regulated kinase-1/2 (ERK), c-Jun N-terminal kinase (JNK), and p38. Therefore, we hypothesized that various components of T. himalayense extract affect multiple factors involved in melanogenesis in B16F10 cells. Our results indicate that T. himalayense extract could potentially be used as a new material for preparing whitening cosmetics.

The biotic effects of lignite on humic acid components conversion during chicken manure composting.

Targeted regulation of composting to convert organic matter into humic acid (HA) holds significant importance in compost quality. Owing to its low carbon content, chicken manure compost often requires carbon supplements to promote the humification progress. The addition of lignite can increase HA content through biotic pathways, however, its structure was not explored. The Parallel factor analysis revealed that lignite can significantly increase the complexity of highly humified components. The lignite addition improved phenol oxidase activity, particularly laccase, during the thermophilic and cooling phases. The abundance and transformation functions of core bacteria also indicated that lignite addition can influence the activity of microbial transformation of HA components. The structural equation model further confirmed that lignite addition had a direct and indirect impact on enhancing the complexity of HA components through core bacteria and phenol oxidase. Therefore, lignite addition can improve HA structure complexity during composting through biotic pathways.

Pulp or Peel? Comparative Analysis of the Phytochemical Content and Selected Cosmetic-Related Properties of Annona cherimola L., Diospyros kaki Thumb., Cydonia oblonga Mill. and Fortunella margarita Swingle Pulp and Peel Extracts.

Fruit peels might be a valuable source of active ingredients for cosmetics, leading to more sustainable usage of plant by-products. The aim of the study was to evaluate the phytochemical content and selected biological properties of hydroglycolic extracts from peels and pulps of Annona cherimola, Diospyros kaki, Cydonia oblonga, and Fortunella margarita as potential cosmetic ingredients. Peel and pulp extracts were compared for their antiradical activity (using DPPH and ABTS radical scavenging assays), skin-lightening potential (tyrosinase inhibitory assay), sun protection factor (SPF), and cytotoxicity toward human fibroblast, keratinocyte, and melanoma cell lines. The total content of polyphenols and/or flavonoids was significantly higher in peel than in pulp extracts, and the composition of particular active compounds was also markedly different. The HPLC-MS fingerprinting revealed the presence of catechin, epicatechin and rutoside in the peel of D. kaki, whereas kaempferol glucoside and procyanidin A were present only in the pulp. In A. cherimola, catechin, epicatechin and rutoside were identified only in the peel of the fruit, whereas procyanidins were traced only in the pulp extracts. Quercetin and luteolinidin were found to be characteristic compounds of F. margarita peel extract. Naringenin and hesperidin were found only in the pulp of F. margarita. The most significant compositional variety between the peel and pulp extracts was observed for C. oblonga: Peel extracts contained a higher number of active components (e.g., vicenin-2, kaempferol rutinoside, or kaempferol galactoside) than pulp extract. The radical scavenging potential of peel extracts was higher than of the pulp extracts. D. kaki and F. margarita peel and pulp extracts inhibited mushroom and murine tyrosinases at comparable levels. The C. oblonga pulp extract was a more potent mushroom tyrosinase inhibitor than the peel extract. Peel extract of A. cherimola inhibited mushroom tyrosinase but activated the murine enzyme. F. margarita pulp and peel extracts showed the highest in vitro SPF. A. cherimola, D. kaki, and F. margarita extracts were not cytotoxic for fibroblasts and keratinocytes up to a concentration of 2% (v/v) and the peel extracts were cytotoxic for A375 melanoma cells. To summarize, peel extracts from all analyzed fruit showed comparable or better cosmetic-related properties than pulp extracts and might be considered multifunctional active ingredients of skin lightening, anti-aging, and protective cosmetics.

Humoral immune response of Galleria mellonella after mono- and co-injection with Hypericum perforatum extract and Candida albicans.

Galleria mellonella is used as a model organism to study the innate immune response of insects. In this study, the humoral immune response was assessed by examining phenoloxidase activity, fungal burden, and the expression of phenoloxidase and antimicrobial peptide genes at different time point following separate and combined injections of Hypericum perforatum extract and a nonlethal dose of Candida albicans. The administration of a plant extract at low doses increased phenoloxidase activity, while higher doses had no effect. Similarly, co-injection of a low dose of the extract with the pathogen allowed half of the yeast cells to survive after 24 h. Co-injection of plant extract with the pathogen decreased the phenoloxidase activity at the end of 4 h compared to C. albicans mono-injection. The phenoloxidase gene expressions was reduced in all experimental conditions with respect to the control. When plant extracts and the pathogen were administered together, gallerimycin and hemolin gene expressions were considerably higher compared to mono-injections of plant extracts and the pathogen. The results of this study reveal that gene activation and regulatory mechanisms may change for each immune gene, and that recognition and signaling pathways may differ depending on the involved immunoregulator.

Antioxidant, Cytotoxic, Anti-Glycation, and Anti-Tyrosinase Compounds from the Leaves of Uvaria Siamensis.

A new oxidized heptene, 7-benzoyloxy-4-hydroxy-1-ethoxy-2E,4Z-heptadiene-1,6-dione, namely siamheptene A (1), together with eight known compounds (2-9), were isolated from the leaves of Uvaria siamensis. Their structures were elucidated by detailed analysis of spectroscopic (IR, 1D and 2D NMR) and mass spectrometric data. Compound 9 is reported for the first time from Uvaria genus. Siamheptene A was evaluated for cytotoxicity against HeLa (cervical cancer cells), A549 (lung cancer cells), and Vero cells using the MTT assay and screened for antibacterial activities. In addition, the isolated compounds (1-7, and 9) were investigated for their antioxidant (DPPH, FRAP and ABTS+ assays), anti-glycation, and anti-tyrosinase properties. Based on our results, compound 1 had mild cytotoxicity against Hela and A549 cancer cell lines, with IC50 ranging from 31.09 to 31.67 µg/mL. Compound 1 also showed antioxidant activities in all tasted assays. However, it showed no detectable activity (>128 µg/mL) against various bacterial strains, and it has no inhibitory effects on tyrosinase enzymes. Among of all tested compounds, chrysin (5), showcased highest anti-glycation and anti-tyrosinase activities. This comprehensive analysis provides highlighting the potential of 1 as a lead compound for further structural modification and development of cytotoxic or antioxidant agents.

Preparation, Characterization, and Antioxidant Activities of Extracts from Amygdalus persica L. Flowers.

A novel water-soluble Amygdalus persica L. flowers polysaccharide (APL) was successfully isolated and purified from Amygdalus persica L. flowers by hot water extraction. Its chemical components and structure were analyzed by IR, GC-MS, and HPLC. APL consisted of rhamnose, arabinose, mannose and glucose in a molar ratio of 0.17:0.034:1.0:0.17 with an average molecular weight of approximately 208.53 kDa and 15.19 kDa. The antioxidant activity of APL was evaluated through radical scavenging assays using 1,1-diphenyl-2-picrylhydrazyl (DPPH), 3-ethylbenzthiazoline-6-sulfonic acid (ABTS), Hydroxyl radical scavenging, Superoxide radical scavenging, and the reducing power activity was also determined in vitro. Besides, in vivo antioxidant experiment, zebrafish (Danio rerio) embryos were treated with different concentrations of APL and then exposed to LPS to induce oxidative stress. Treatment with APL at 50 or 100 µg/mL significantly reduced LPS-induced oxidative stress in the zebrafish, demonstrating the strong antioxidant activity of APL. Moreover, the effect of APL on zebrafish depigmentation was tested by analyzing the tyrosinase activity and melanin content of zebrafish embryos. APL showed a potential reduction in the total melanin content and tyrosinase activity after treatment. This work provided important information for developing a potential natural antioxidant in the field of cosmetics and food.

African Under-Utilized Medicinal Leafy Vegetables Studied by Microtiter Plate Assays and High-Performance Thin-Layer Chromatography-Planar Assays.

Biological activities of six under-utilized medicinal leafy vegetable plants indigenous to Africa, i.e., Basella alba, Crassocephalum rubens, Gnetum africanum, Launaea taraxacifolia, Solanecio biafrae, and Solanum macrocarpon, were investigated via two independent techniques. The total phenolic content (TPC) was determined, and six microtiter plate assays were applied after extraction and fractionation. Three were antioxidant in vitro assays, i.e., ferric reducing antioxidant power (FRAP), cupric reduction antioxidant capacity (CUPRAC), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging, and the others were enzyme (acetylcholinesterase, butyrylcholinesterase, and tyrosinase) inhibition assays. The highest TPC and antioxidant activity from all the methods were obtained from polar and medium polar fractions of C. rubens, S. biafrae, and S. macrocarpon. The highest acetyl- and butyrylcholinesterase inhibition was exhibited by polar fractions of S. biafrae, C. rubens, and L. taraxacifolia, the latter comparable to galantamine. The highest tyrosinase inhibition was observed in the n-butanol fraction of C. rubens and ethyl acetate fraction of S. biafrae. In vitro assay results of the different extracts and fractions were mostly in agreement with the bioactivity profiling via high-performance thin-layer chromatography-multi-imaging-effect-directed analysis, exploiting nine different planar assays. Several separated compounds of the plant extracts showed antioxidant, α-glucosidase, α-amylase, acetyl- and butyrylcholinesterase-inhibiting, Gram-positive/-negative antimicrobial, cytotoxic, and genotoxic activities. A prominent apolar bioactive compound zone was tentatively assigned to fatty acids, in particular linolenic acid, via electrospray ionization high-resolution mass spectrometry. The detected antioxidant, antimicrobial, antidiabetic, anticholinesterase, cytotoxic, and genotoxic potentials of these vegetable plants, in particular C. rubens, S. biafrae, and S. macrocarpon, may validate some of their ethnomedicinal uses.

[Comparison on biological activities of Lycium barbarum polysaccharides extracted with five methods].

Studying the physicochemical properties and biological activities of Lycium barbarum polysaccharides(LBPs) is of great significance. The previous study had extracted LBPs(LBP-1, LBP-2, LBP-3, LBP-4, and LBP-5) by five different methods(cold water extraction, boiling water reflux extraction of the residue after cold water extraction, ultrasonic extraction with 50% ethanol, ultrasonic extraction with 25% ethanol of the residue after 50% ethanol extraction, and hot water extraction). In this study, the structures of the obtained five LBPs were characterized by UV spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Furthermore, the antioxidant, blood lipid-lowering, nitrosation-inhibting, acetylcholinesterase-inhibiting, and tyrosinase-inhibiting activities of the five LBPs were measured in vitro. The results showed that high-temperature extraction destroyed the polysaccharide structure, while ultrasound-assisted extraction ensured the structural integrity. The thermal stability and degradation behaviors differed among the five LBPs. However, the UV spectroscopic results of the five LBPs did not show significant differences, and all of the five LBPs showed the characteristic absorption peaks of proteins. LBP-3 and LBP-4 exhibited strong antioxidant activity, while LBP-3 had the strongest blood lipid-lowering activity. In addition, LBP-3 outperformed other LBPs in inhibiting nitrosation and acetylcholineste-rase, and LBP-2 showed the strongest inhibitory effect on tyrosinase. This study explored the effects of different extraction methods on the physicochemical properties and biological activities of LBPs, with a view to providing a basis for the selection of suitable extraction methods to obtain LBPs with ideal biological activities.

Identification of tyrosinase inhibitors in defatted seeds of evening primrose (Oenothera biennis L.) by affinity-labeled molecular networking.

The defatted seeds of evening primrose (DE), a by-product of evening primrose oil extraction, are currently underutilized. This study aimed to valorize DE by examining its effects on melanogenesis and tyrosinase activity in zebrafish embryos and in vitro, and an innovative affinity-labeled molecular networking workflow was proposed for the rapid identification of tyrosinase inhibitors in DE. Our results indicated DE significantly reduced melanin content (53.3 % at 100 µg/mL) and tyrosinse activity (80.05 % for monophenolase and 70.40 % for diphenolase at 100 µg/mL). Furthermore, through the affinity-labeled molecular networking approach, 20 compounds were identified as potential tyrosinase inhibitors within DE, predominantly flavonoids and tannins characterized by catechin and galloyl substructures. Seven of these compounds were isolated and their inhibitory effects on tyrosinase were validated using functional assays. This study not only underscores the potential of DE as a rich source of natural tyrosinase inhibitors but also establishes the effectiveness of affinity-labeled molecular networking in pinpointing bioactive compounds in complex biological matrices.

The whitening effect of cuscutin responsible for traditional use of Bergenia purpurascens.

ETHNOPHARMACOLOGICAL RELEVANCE: The roots and rhizomes of Bergenia purpurascens (Hook. f. et Thomson) Engl., was used as a sunscreen to protect against ultraviolet rays in Tibet of China historically, but its skin whitening constituents and pharmacological effects of this plant remained unknown. AIM OF THE STUDY: To investigate the anti-melanogenesis effect of B. purpurascens in vitro and in vivo, and then explore the preliminary mechanism. MATERIALS AND METHODS: An ultraviolet B (UVB)-induced skin injury model of mice was used to verify the ameliorative effect of B. purpurascens extract (BPE) on ultraviolet damage. Then, alpha-melanocyte stimulating hormone (α-MSH)-induced murine melanoma cell line (B16F10) melanin generation model was further adopted to approval the effects of BPE and its bioactive compound, cuscutin, in vitro. Moreover, α-MSH stimulated melanogenesis model in zebrafish was employed to confirm the anti-pigmentation effect of cuscutin. Then, proteins expressions associated with melanin production were observed using western blotting assay to explore preliminary mechanism. RESULTS: BPE inhibited UVB-induced mice injury and restored skin barrier function observably in vivo. BPE and cuscutin suppressed the overproduction of melanin in α-MSH induced B16F10 significantly, in which cuscutin exhibited better effect than well-known whitening agent α-arbutin at same 10 µg/mL concentration. Moreover, the pigmentation of zebrafish embryo was decreased by cuscutin. Finally, cuscutin showed significant downregulation of expressions of tyrosinase (TYR) and tyrosinase related protein-1 (TRP-1), TRP-2 and microphthalmia-associated transcription factor (MITF) in the melanogenic signaling pathway. CONCLUSION: B. purpurascens extract and its major bioactive constituent, cuscutin, showed potent anti-melanogenesis and skin-whitening effect by targeting TYR and TRP-2 proteins for the first time, which supported its traditional use.

Inhibition of α-melanocyte-stimulating hormone-induced melanogenesis and molecular mechanisms by polyphenol-enriched fraction of Tagetes erecta L. flower.

BACKGROUND: The pursuit for safe and efficacious skin-whitening agents has prompted a dedicated exploration of plant-derived compounds. Notably, Tagetes erecta L. flowers have been used as a medicinal extract and possessed in vitro mushroom tyrosinase activity. However, whether polyphenol-enriched fraction extracted from T. erecta L. flowers (TE) regulates melanogenesis within cellular and animal models has not yet been investigated. PURPOSE: This study aimed to investigate the effect of TE as a prospective inhibitor of melanogenesis. METHODS: Through advanced UPLC-QTof/MS analysis, the components of TE were analyzed. Anti-melanogenic effects of TE were evaluated in α-melanocyte-stimulating hormone (α-MSH)-stimulated B16F10 melanoma cells by measuring cell viability assay, extracellular and intracellular melanin biosynthesis, cyclic adenosine monophosphate (cAMP) production, and melanogenesis-related gene and protein expression. Zebrafish larvae were employed for in vivo studies, assessing both heart rate and melanogenesis. Furthermore, molecular docking analyses were employed to predict the interaction between TE components and the melanocortin 1 receptor (MC1R). Direct binding activity of TE components to MC1R was compared with [Nle4, d-Phe7]-MSH (NDP-MSH). RESULTS: TE was found to contain significant phenolic compounds such as patulitrin, quercetagetin, kaempferol, patuletin, and isorhamnetin. This study revealed that TE effectively inhibits melanin biosynthesis in both in vitro and in vivo models. This inhibition was attributed to interference of TE with the cAMP-cAMP response element-binding protein (CREB)-microphthalmia-associated transcription factor (MITF)-tyrosinase pathway, which plays a pivotal role in regulating melanogenesis. Importantly, TE exhibited the remarkable ability to curtail α-MSH-induced melanogenesis in zebrafish larvae without impacting heart rates. Molecular docking analyses predicted that the components of TE possibly interact with the melanocortin 1 receptor, suggesting their role as potential inhibitors of melanin biosynthesis. However, through the direct binding activity compared with NDP-MSH, any TE components did not directly bind to MC1R, suggesting that TE inhibits α-MSH-induced melanogenesis by inhibiting the cAMP-mediated intracellular signaling pathway. The assessment of anti-melanogenic activity, conducted both in vitro and in vivo, revealed that patulitrin and patuletin exhibited significant inhibitory effects on melanin formation, highlighting their potency as major contributors. DISCUSSION: This investigation demonstrated the considerable potential of TE as a natural remedy endowed with remarkable anti-melanogenic properties. The demonstrated capacity of TE to attenuate melanin production by modulating the cAMP-CREB-MITF-tyrosinase pathway underscores its central role in management of disorders associated with excessive pigmentation. Importantly, the implications of these findings extend to the cosmetics industry, where TE emerges as a prospective and valuable ingredient for the formulation of skin-whitening products. The elucidated interactions between TE components and MC1R not only provide insight into a potential mechanism of action but also elevate the significance of this study. In summary, this study not only contributes to our comprehension of pigmentation-related conditions but also firmly establishes TE as a secure and natural strategy for the regulation of melanin production. The innovative aspects of TE propel it into the forefront of potential interventions, marking a noteworthy advancement in the pursuit of effective and safe solutions for pigmentation disorders.

Effects of Enterococcus faecium (R8a) on nonspecific immune gene expression, immunity and intestinal flora of giant tiger shrimp (Penaeus monodon).

In this study, Penaeus monodon were gave basic feed supplemented with three levels of Enterococcus faecium. Then, the expression of non-specific immunity-related genes, and the activities of total antioxidant capacity (T-AOC), superoxide dismutase (SOD), malondialdehyde (MDA), acid phosphatase (ACP), alkaline phosphatase (AKP), phenol oxidase (PO) were evaluated. Meanwhile, the disease resistance test and intestinal flora determination were conducted. The results showed that the MDA levels of 2% and 5% E. faecium groups were significantly lower than that of the control group (P < 0.05). While the SOD and T-AOC and ACP and AKP of experimental groups were significantly higher (P < 0.05), the PO of experimental groups were significantly lower than that of the control group (P < 0.05). In addition, the expressions of immunity-related genes (tlr22, dorsal, lysozyme, crustin, imd, and relish) in the 2% and 5% E. faecalis groups were significantly greater than those in the control group (P < 0.05). After P. monodon was challenged with Vibrio parahaemolyticus for 7 days, the average cumulative mortality of P. monodon in the 2% and 5% groups were significantly lower than that in the 0% group (P < 0.05). With the increase of feeding time, the number of effective OTUs in each group showed a downward trend. At the 14th d, Proteobacteria, Bacteroidetes and Firmicutes, the dominant flora in the intestinal tract of P. monodon. In summary, supplied with E. faecium could increase the expression of non-specific immunity-related genes, enhance the immune capacity of P. monodon.

Study on the preparation and enzyme inhibitory activity of polyphenols from Sargassum pallidum.

This study aimed to obtain a high yield and purity of Sargassum pallidum polyphenol extracts (SPPE) and study its enzyme activity. Fresh Sargassum pallidum seaweed was selected for optimization of ultrasound-assisted extraction (UAE) conditions and purification conditions using macroporous resin and Sephadex LH20 to obtain SPPE. The SPPE was characterized using UPLC-QTOF-MS/MS and α-amylase, α-glucosidase, tyrosinase, and AchE inhibitory activity were determined. The maximum extraction rate of SPPE was 7.56 mg GAE/g and the polyphenol purity reached 70.5% after macroporous resin and Sephadex LH-20 purification. A total of 50 compounds were identified by UPLC-QTOF-MS/MS. The IC50 values of SPPE were 334.9 µg/mL, 6.290 µg /mL, 0.834 mg /mL and 0.6538 mg /mL for α-amylase, α-glucosidase, tyrosinase and AchE, respectively. Molecular docking technology further revealed the effects of SPPE on the above enzymes. This study provided information on the potential hypoglycemic, whitening and anti-Alzheimer's disease biological activities of SPPE, which had guiding significance for the purification and development of other seaweed polyphenols.

6'-O-Caffeoylarbutin from Quezui Tea: A Highly Effective and Safe Tyrosinase Inhibitor.

Tyrosinase is vital in fruit and vegetable browning and melanin synthesis, crucial for food preservation and pharmaceuticals. We investigated 6'-O-caffeoylarbutin's inhibition, safety, and preservation on tyrosinase. Using HPLC, we analyzed its effect on mushroom tyrosinase and confirmed reversible competitive inhibition. UV_vis and fluorescence spectroscopy revealed a stable complex formation with specific binding, causing enzyme conformational changes. Molecular docking and simulations highlighted strong binding, enabled by hydrogen bonds and hydrophobic interactions. Cellular tests showed growth reduction of A375 cells with mild HaCaT cell toxicity, indicating favorable safety. Animal experiments demonstrated slight toxicity within safe doses. Preservation trials on apple juice showcased 6'-O-caffeoylarbutin's potential in reducing browning. In essence, this study reveals intricate mechanisms and applications of 6'-O-caffeoylarbutin as an effective tyrosinase inhibitor, emphasizing its importance in food preservation and pharmaceuticals. Our research enhances understanding in this field, laying a solid foundation for future exploration.

Identification and molecular docking of tyrosinase inhibitory peptides from allophycocyanin in Spirulina platensis.

BACKGROUND: Tyrosinase, a copper-containing metalloenzyme with catalytic activity, is widely found in mammals. It is the key rate-limiting enzyme that catalyzes melanin synthesis. For humans, tyrosinase is beneficial to the darkening of eyes and hair. However, excessive deposition of melanin in the skin can lead to dull skin color and lead to pigmentation. Therefore, many skin-whitening compounds have been developed to decrease tyrosinase activity. This study aimed to identify a new tyrosinase inhibitory peptide through enzymatic hydrolysis, in vitro activity verification, molecular docking, and molecular dynamics (MD) simulation. RESULTS: A tripeptide Asp-Glu-Arg (DER) was identified, with a '-CDOCKER_Energy' value of 121.26 Kcal mol-1 . DER has effective tyrosinase inhibitory activity. Research shows that its half maximal inhibitory concentration value is 1.04 ± 0.01 mmol L-1 . In addition, DER binds to tyrosinase residues His85, His244, His259, and Asn260, which are key residues that drive the interaction between the peptide and tyrosinase. Finally, through MD simulation, the conformational changes and structural stability of the complexes were further explored to verify and supplement the results of molecular docking. CONCLUSION: This experiment shows that DER can effectively inhibit tyrosinase activity. His244, His259, His260, and Asn260 are the critical residues that drive the interaction between the peptide and tyrosinase, and hydrogen bonding is an important force. DER from Spirulina has the potential to develop functional products with tyrosinase inhibition. © 2024 Society of Chemical Industry.

Phytochemical analyses by LC-HRMS, FTIR spectral analysis, antioxidant, antidiabetic and antityrosinase activity of Crataegus orientalis Pall. ex M. Bieb fruit extracted with various solvents.

BACKGROUND: Crataegus orientalis Pall. ex M. Bieb fruit (COPMB) is extensively used as a source of various products in the medicinal-aromatic field and holds the potential for erosion control, ornamental purposes, food source, and economic benefits for forest villagers from its fruits. This study aims to determine the chemical components and biological activities of extracts prepared from COPMB using different solvents. RESULTS: The present work was designed to define the antioxidant activity [phosphomolybdenum (total antioxidant capacity), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), cupric ion-reducing antioxidant capacity (CUPRAC) and metal chelating activity (MCA)], phytochemical screening analysis, enzyme inhibitor (α-amylase, α-glucosidase and tyrosinase) potential, and liquid chromatography-high resolution mass spectrometry (LC-HRMS) secondary metabolite profiling in different extracts of COPMB. The results of LC-HRMS revealed that fumaric acid was the main phenolic compound in all extracts. Among the extracts, ethyl acetate extract has the highest phytochemical and antioxidant properties [total phenolic content (TPC): 32.5 mg GAE/g, total flavonoid content (TFC): 12.2 mg QE/g, ABTS: 213.0 mg TE/g; CUPRAC: 126.0 mg TE/g, MCA: 145.0 mg EDTA/g; FRAP: 122.8 mg TE/g; TAC: 2.8 mmol TE/g]. Ethyl acetate and methanol extracts are more effective in α-amylase (0.27 ± 0.01 mg/mL; 0.12 ± 0.00 mg/mL), α-glucosidase (0.63 ± 0.02 mg/mL; 0.77 ± 0.02 mg/mL) and tyrosinase (0.03 ± 0.00 mg/mL; 0.03 ± 0.00 mg/mL) enzyme inhibition potentials compared to standard acarbose (0.75 ± 0.02 mg/mL for α-amylase; 1.11 ± 0.03 mg/mL for α-glucosidase) and kojic acid (0.04 ± 0.00 mg/mL). CONCLUSION: The findings from this study suggest that COPMB could serve as a valuable source of natural agents for the food and pharmaceutical industry. © 2024 Society of Chemical Industry.