This study presents the first evidence of the ability of two synthetic peptides, SA-10 (SSYYPFKGFA) and VI-10 (VKGPGLYSDI), derived from longan seed hydrolysates to inhibit intestinal glucose absorption via SGLT1 and GLUT2 transporters. Molecular docking revealed strong binding affinities: SA-10 to SGLT1 (-9.1 kcal/mol) and VI-10 to GLUT2 (-8.7 kcal/mol), involving hydrogen bonds and hydrophobic interactions at key glucose-binding sites, suggesting competitive inhibition. Molecular dynamics simulations over 100 ns supported these findings, demonstrating structural stability and compactness of the peptide-transporter complexes, as indicated by sustained RMSD and Rg values throughout the simulation trajectory. In vitro assays using Caco-2 cells showed that both peptides significantly reduced glucose uptake in a dose-and time-dependent manner, achieving approximately 50% reduction at 1.00 mM after 3 h. Western blot analysis confirmed SA-10 downregulated SGLT1 expression, while VI-10 reduced both SGLT1 and GLUT2 levels. These findings suggest that longan seed-derived peptides can modulate both glucose uptake and transporter expression in intestinal cells. Importantly, SA-10 and VI-10 represent novel glucose transporter inhibitors and hold promise for development as functional food ingredients or nutraceuticals to manage postprandial hyperglycemia and support glycemic control in diabetes management.

[This corrects the article DOI: 10.1371/journal.pone.0304701.].

Geranylgeranyl pyrophosphate (GGPP) is a key precursor for carotenoids, chlorophyll derivatives, and numerous high-value isoprenoids used in food, nutraceutical, and pharmaceutical industries. Microbial and photosynthetic production approaches offer promising alternatives to conventional plant extraction and chemical synthesis; however, further optimization and comprehensive sustainability assessments are required for industrial implementation. In this study, a photosynthetic production platform was developed by redirecting carbon flux in Synechocystis sp. PCC 6803 to enhance GGPP production via activation of the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway. Two engineered mutants, ΔP (deficient in poly(3-hydroxybutyrate) synthesis) and ΔGP (deficient in both glycogen and poly(3-hydroxybutyrate) synthesis), were evaluated alongside the wild-type (WT) strain under multiple physiological conditions, including carbon supplementation and UV radiation. Redirecting cellular carbon metabolism significantly enhanced pigment accumulation and overall isoprenoid biosynthesis, with ΔGP strain showing the greatest improvement. Elevated intracellular GGPP levels were observed under all tested conditions, with the highest concentrations obtained under glucose supplementation and UV treatment. The best-performing strain exhibited approximately twelvefold increase in GGPP content relative to the control. These findings demonstrate that rational metabolic engineering of cyanobacteria can markedly improve precursor supply for isoprenoid synthesis, establishing an efficient photosynthetic platform for producing natural pigments, flavor compounds, and other value-added bioproducts.

This study investigates the potential of bee pollen protein hydrolysate (BPPH) as a natural source of bioactive peptides capable of inhibiting dipeptidyl peptidase IV (DPP-IV) for the management of type 2 diabetes mellitus (T2DM), a metabolic disorder characterized by insulin resistance and hyperglycemia. BPPH was generated through pepsin–pancreatin digestion, followed by ultrafiltration and RP-HPLC purification. LC-Q-TOF-MS/MS analysis identified Ala-Thr-His-Ala-Leu-Leu-Ala (ATHALLA, AA-7) as a predominant peptide associated with DPP-IV inhibitory activity. AA-7 exhibited strong DPP-IV inhibitory activity (IC50 = 52.63 ± 2.32 µM) relative to the reference inhibitor diprotin A (IC50 = 22.4 ± 1.29 µM). Molecular docking predicted stable binding of AA-7 within the DPP-IV catalytic pocket, mediated by hydrogen bonding and hydrophobic interactions with key residues. AA-7 also modulated glucose uptake in Caco-2 cells, influencing SGLT1 and GLUT2 gene expression in a dose-dependent manner. Docking analysis suggested potential interactions with selected SGLT1 and GLUT2 residues, providing structural support for the observed cellular responses rather than definitive mechanistic evidence. In silico ADMET analysis indicated poor passive membrane permeability and limited predicted intestinal absorption, along with minimal CYP450 interactions and low predicted toxicity, highlighting potential pharmacokinetic limitations while supporting a favorable safety profile. These findings highlight AA-7 as a dual-action peptide with demonstrated DPP-IV inhibitory activity and the ability to modulate glucose transport in vitro, supporting the potential of bee-pollen-derived peptides for glycemic regulation and functional food or nutraceutical applications.

Pestalotiopsis sensu lato species have gained attention as emerging primary pathogens on economically important crops, shifting from their previous roles as weak pathogens, saprobes, or endophytes. Coniferous trees in Taiwan have recently shown fungal infection symptoms, prompting further investigation. Field surveys revealed leaf spots and blight on six cultivated conifer species: Calocedrus formosana, Chamaecyparis formosensis, Chamaecyparis obtusa var. formosana (Cupressaceae), and Podocarpus costalis, Podocarpus macrophyllus, and Podocarpus nakaii (Podocarpaceae). This study aimed to identify the causal fungal taxa and assess their fungicide sensitivity. A total of 66 Pestalotiopsis sensu lato isolates were recovered from diseased tissues. Phylogenetic analyses using ITS, tef1-α, and tub2 sequences, combined with morphological characteristics, revealed 10 taxa including six species and four tentative clades from the genera Pestalotiopsis, Pseudopestalotiopsis, and Neopestalotiopsis. Six species (P. neolitseae, P. parva, P. subshorea, P. trachycarpicola, Pseudopestalotiopsis elaeidis, and Ps. ixorae) represent first reports on these conifer hosts. Neopestalotiopsis and Pestalotiopsis were most frequently isolated, while Pseudopestalotiopsis was less common. Fungicide assays revealed that fluazinam exhibited the strongest and broadest antifungal activity, while other fungicides showed species-specific efficacy. These results highlight the importance of accurate species identification for effective disease management and fungicide selection. This study highlights Pestalotiopsis sensu lato emergence as conifer pathogens in Taiwan and underscores the need for integrated management strategies with field-based fungicide evaluations.

This study investigates the immunomodulatory and antioxidative potential of SGP31, a sulfated polysaccharide derived from the seaweed Caulerpa lentillifera. Transcriptomic profiling of RAW 264.7 macrophages treated with SGP31 indicated dose-dependent modulation of genes associated with immune responses and oxidative stress regulation. Key genes, including Tnf, Il6, Hmox1, and Txnrd1 were differentially expressed, suggesting activation of inflammatory and antioxidant pathways. Pathway enrichment analysis highlighted signaling networks, including cytokine–cytokine receptor interaction and AGE–RAGE signaling, which may contribute to the observed cellular responses. To validate these transcriptomic findings, qRT-PCR analysis was conducted on selected genes. SGP31 significantly increased the expression of Tnf and Il6 relative to the untreated control, although expression levels remained considerably lower than those induced by LPS, suggesting a moderate immunostimulatory effect. The antioxidant-related gene Hmox1 was markedly upregulated at higher SGP31 concentrations, whereas Nqo1 expression decreased in a concentration-dependent manner. Functional assays revealed no cytotoxicity across the tested concentrations, with cell viability remaining above 88%. SGP31 also increased nitric oxide (NO) production in a dose-dependent manner, consistent with its immunostimulatory potential. Collectively, these findings suggest that SGP31 can influence both inflammatory cytokines and antioxidant genes in macrophages, supporting its promise as a natural bioactive compound for immune and antioxidant modulation.

The research focuses on the peptide AILQSYSAGKTK (AK-12), synthesized from the marine microalga Synechococcus, to determine its antioxidant and apoptotic properties. Antioxidant activity is attributed to residues like tyrosine and glutamic acid, which chelate metal ions and neutralize free radicals. In silico analysis indicates that AK-12 is non-toxic, non-allergenic, and suitable for oral consumption, despite poor intestinal permeability. According to circular dichroism (CD) analysis, AK-12 predominantly adopts a random coil structure. AK-12 reduced Caco-2 cell viability in a dose-dependent manner and lowered intracellular ROS, confirming notable antioxidant activity. Molecular docking analysis indicated that AK-12 exhibits a strong binding affinity for Bcl-2, suggesting its potential to inhibit the protein’s anti-apoptotic functions. Flow cytometry confirmed that AK-12 induced apoptosis in Caco-2 cells dose-dependently. Flow cytometry indicated dose-dependent apoptosis, supported by RT-qPCR results showing upregulation of caspase-8 and caspase-9 mRNA, and a moderate increase in caspase-3. Western blot analysis further substantiated these findings by showing increased expression of Bax, and caspase-9, coupled with reduced Bcl-2 levels, confirming the mitochondrial pathway’s central role in apoptosis induction. These findings suggest that AK-12 has potential as a functional food ingredient for colon cancer treatment due to its dual antioxidant and pro-apoptotic activities.

In this study, the peptide WV-9, obtained from Hericium erinaceus (Lion's mane mushroom), was shown to modulate the Keap1–Nrf2 antioxidant pathway through direct molecular interaction. Molecular docking and molecular dynamics simulations demonstrated that WV-9 binds stably and specifically to the Keap1 Kelch domain by mimicking the ETGE motif of Nrf2. This interaction suggests a competitive mechanism that may disrupt Keap1-mediated degradation of Nrf2, promoting its nuclear translocation and transcriptional activation. In vitro analysis using RAW264.7 macrophage cells revealed that WV-9 enhanced the expression of key antioxidant genes, including superoxide dismutase 2 (Sod-1), NAD(P)H quinone dehydrogenase 1 (Nqo-1), and heme oxygenase 1 (HO-1). Importantly, protein-level validation by Western blot analysis demonstrated a significant upregulation of HO-1 expression in WV-9-treated cells, whereas other antioxidant enzymes, such as SOD-1 and CAT, showed increasing trends that did not reach statistical significance, indicating a selective activation of the Nrf2 antioxidant response. In silico ADMET analysis predicted a favorable safety profile, with low cytochrome P450 interaction and minimal toxicity. Unlike conventional Nrf2 activators such as sulforaphane, which act via redox-based mechanisms, WV-9 operates through direct interference with the Keap1–Nrf2 interface. These findings support the potential application of WV-9 as a natural therapeutic candidate or a bioactive ingredient in functional foods aimed at combating oxidative stress and immune dysregulation.

Marine microalgae including Synechococcus sp. VDW offer the potential to serve as a source of bioactive peptides offering valuable antioxidant and antimelanogenic qualities for use in the pharmaceutical and cosmetics industries. At present, however, the use of such peptides is challenging due to their poor physicochemical stability. This research therefore sought to achieve the production and characterization of a stable nanoemulsion system based upon the use of synthetic Synechococcus-derived peptides through the process of high-pressure homogenization (HPH). Preparation of the nanoemulsions involved the use of Tween-80 and caprylic/capric triglyceride at a pressure of 7,500 psi to perform homogenization for varying durations of 15, 30 and 45 min. Using the optimized formulation with 0.1% w/w peptide for a time of 45 min resulted in 122.16 nm droplets while the zeta potential was −80.09 mV and the PDI (polydispersity index) value was 0.13. Colloidal stability could be considered high, while physical stability under thermal cycling, centrifugation and freeze-thaw cycles was very good, with no phase separation. For all testing intervals, the viscosity and refractive index were stable. It can thus be argues that the HPH approach is suitable to produce peptide-loaded nanoemulsions offering good stability and useful physicochemical characteristics. The developed nanoemulsion system has been optimized to offer potential for applications involving the transdermal delivery of marine peptides in the cosmeceutical sector and for a range of dermal therapies. HIGHLIGHTS Developed a stable peptide-loaded nanoemulsion using high-pressure homogenization (HPH) at 7,500 psi for 45 min. Achieved small, uniform droplet size (122.16 nm), high zeta potential (−80.09 mV) and low PDI (0.13), indicating strong colloidal stability. Nanoemulsion exhibited excellent physical stability under centrifugation, freeze–thaw and heating–cooling cycles. Increased peptide concentration led to decreased pH and viscosity, optimizing flow and emulsification properties. Potential application in transdermal delivery systems for cosmeceuticals and dermatological formulations. GRAPHICAL ABSTRACT

Excess melanin production leads to hyperpigmentation with psychological and cosmetic effects. Tyrosinase, key in melanin synthesis, is a target for treatment. This study explores tyrosinase inhibition by peptides from Curcuma wanenlueanga rhizomes. Papain was used to hydrolyze the crude proteins from rhizomes to obtain hydrolysates which underwent fractionation to acquire fractions of differing molecular weight. The most effective inhibitory action to counter tyrosinase was observed for the < 1 kDa fraction, for which the IC50 value was 16.75 +/- 1.71 g/mL. Reverse-phase high-performance liquid chromatography (RP-HPLC) was performed to isolate the bioactive peptides VY-8 (VAPVSLSY) and FF-6 (FDNSYF). Both exhibited the competitive inhibition of tyrosinase, recording values for Ki of 1.44 +/- 0.07 mM and 1.85 +/- 0.09 mM respectively, while the molecular docking findings were indicative of strong binding affinities. There were strong interactions between the peptides and key tyrosinase residues in the form of hydrogen bonds and hydrophobic interactions, from which the possibility of powerful enzyme inhibition can be inferred. Melanin synthesis could be decreased by 40 % and 30 % in vitro by VY-8 and FF-6 respectively, when tested in alpha-MSH-stimulated B16F10 melanoma cells at concentrations considered non-cytotoxic. Other genes and proteins related to melanogenesis were also notably downregulated by both peptides according to both quantitative PCR analysis and Western blot results. An in vivo zebrafish toxicity assay showed VY-8 had no significant effect on cell death, while 50 mu M reduced melanin content. These peptides have potential for safe and sustainable hyperpigmentation treatment in cosmetics and pharmaceuticals.

This research sought to examine the diabetic inhibitory potential of bioactive peptides derived from longan seed protein hydrolysates (LSH). These hydrolysates were produced using pepsin and pancreatin to simulate gastrointestinal digestion, and upon testing were revealed to inhibit alpha-amylase (IC50 = 196.91 mu g/mL), alpha-glucosidase (IC50 = 25.29 mu g/mL), and dipeptidyl peptidase-IV (DPP-IV) enzymes (IC50 = 116.10 mu g/mL). Results from ultrafiltration revealed the strongest inhibition was achieved by the smallest peptide fraction. Nine active fractions were classified via RP-HPLC purification, and the most effective inhibitors were found to be the fractions F1, F4, and F8. LC-Q-TOF MS/MS was carried out to identify a total of seven peptide sequences, with SSYYPFKGFA (SA-10) and VKGPGLYSDI (VI-10) providing the strongest inhibitory properties according to the molecular docking analysis. Both peptides exhibited antidiabetic effects, as demonstrated by in vitro and enzymatic kinetic assays. SA-10 showed competitive, uncompetitive, and mixed-type inhibition against alpha-amylase, alpha-glucosidase, and DPP-IV, respectively. Conversely, VI-10 exhibited uncompetitive inhibition of alpha-amylase and mixed-type inhibition of both alpha-glucosidase and DPP-IV. Preliminary ADMET predictions of pharmacokinetic properties suggest that LSH peptides may exhibit adequate solubility and minimal toxicity. However, further in vivo studies and clinical trials are essential to gain comprehensive insight and clarify their actual efficacy, safety, and pharmacokinetic profile in diabetes treatment. Overall, the multi-targeted approach of longan seed peptides suggested a potential avenue in the control of diabetes and postprandial hyperglycemia, since SA-10 and V-I10 demonstrated useful abilities in boosting insulin secretion and slowing the digestion of carbohydrates.

This study investigates the bioactive potential of the peptide DGIFVLNY (DY-8), derived from the rhizomes of Zingiber cassumunar, a medically important plant with extensive traditional medicinal functions and bioactivities, for its potential application in bio-based cosmetic and personal care products. The findings based on molecular docking reveal the ability of this peptide to bind to the active tyrosinase site, with inhibitory effects. To investigate this inhibitory process further, the peptides were synthesized for testing. The findings presented the inhibition of tyrosinase with an IC50 value of 0.18 +/- 0.01 mu g/mL for the mono-phenolase activity, rising to 0.81 +/- 0.06 mu g/mL for the di-phenolase activity. Construction of a Lineweaver-Burk plot revealed competitive type inhibition. The peptide was employed at various concentrations in the range of 0-100 mu M in order to treat B16F10 cells. The outcome revealed the absence of significant cytotoxicity. The peptide was shown to significantly inhibit tyrosinase activity and by extension reduce the production of melanin. Further examination of the inhibition of melanin synthesis was carried out via qRT-PCR (quantitative reverse transcription polymerase chain reaction) involving MITF (microphthalmia-associated transcription factor), TYR (tyrosinase), TRP-1 (tyrosinaserelated protein-1), and TRP-2 (tyrosinase-related protein-2). The in vivo efficacy of DY-8 was further validated in zebrafish embryos, where a significant reduction in pigmentation was observed. These findings highlight DY-8 as a promising, sustainable, and natural bio-based ingredient for the cosmetic and personal care industries, emphasizing the industrial potential of Zingiber cassumunar in developing functional skincare products.

Serpentine soils are predominantly distributed along the Circum-Pacific margin and the Mediterranean, including eastern Taiwan. These soils are characterized by high levels of heavy metals, including nickel and chromium, and a low calcium-to-magnesium ratio, creating a unique environment that fosters microorganisms with specialized traits. In this study, culture-dependent isolation methods were used to elucidate the composition of culturable fungal communities in serpentine-characterized paddy fields in eastern Taiwan. A total of 154 fungal isolates were isolated from serpentine paddy fields in eastern Taiwan. These isolates were grouped into 79 strains based on colony morphology and were subsequently evaluated through morphological and multi-locus phylogenetic analyses. The results revealed that 60% of the strains belong to the class Dothideomycetes, followed by 21% in Sordariomycetes and 19% in Eurotiomycetes. At the genus level, Westerdykella was the dominant genus, presenting 35% of the total of isolated strains, followed by Pyrenochaetopsis (20%), Talaromyces (19%), and Pseudorhypophila (8%). The study reports 11 novel species: Cylindrotrichumformosanum sp. nov., Dimorphisetaformosana sp. nov., D.serpentinicola sp. nov., Parasarocladiumformosum sp. nov., Phialoparvumformosanum sp. nov., Poaceascomaserpentinum sp. nov., Pseudorhypophilaformosana sp. nov., Sarocladiumformosanum sp. nov., S.serpentinicola sp. nov., Talaromycestaiwanensis sp. nov., and Westerdykellaformosana sp. nov. Additionally, 11 known species are reported for the first time in Taiwan: Pseudothielaviaterricola, Pseudoxylomycesaquaticus, Pyrenochaetopsisoryzicola, Py.paucisetosa, Setophaeosphaeriamicrospora, Talaromycesadpressus, T.thailandensis, Westerdykellaaquatica, W.capitulum, W.dispersa, and W.globosa. In addition, this study presents the first documented asexual morph within the genus Poaceascoma, represented by P.serpentinum. These discoveries will be valuable for future evaluations of the potential uses and functions of these species as bioremediation agents.

The use of agricultural waste for the production of value-added ingredients was investigated. Defective green coffee beans were utilized as alternative feedstocks for the production of peptides. The crude peptides were produced by enzymatic hydrolysis, followed by membrane filtration and centrifugation. Subsequently, hydrolysate peptides were encapsulated via spray drying with maltodextrin as the carrier, facilitating their use as a functional ingredient in food supplements. This study aimed to produce hydrolysate peptides from defatted defective green coffee beans by supercritical carbon dioxide with ethanol as a cosolvent. Additionally, their environmental impacts (gate to gate) were evaluated and analyzed using the life cycle assessment approach. Data obtained from pilot-scale production of 10 L of oil extract and 50 L of peptide extract were used to examine the environmental consequences of the various treatments. Two scenarios of downstream processing were examined for equivalent antioxidant activity: spray-drying without maltodextrin (Scenario 1) and spray-drying with maltodextrin encapsulation (Scenario 2). Scenario 2 consumed less electricity than Scenario 1 due to its shorter operating time and lower environmental impact compared to Scenario 1. Additionally, its encapsulated form is suitable for antioxidant retention and the storage of functional ingredients. The greatest environmental impact arose from supercritical carbon dioxide with ethanol extraction, which affected 8 out of 15 midpoint categories, followed by spray dry encapsulation, which affected 7 out of 15 midpoint categories. Solutions for improvement, such as carbon dioxide and/or ethanol recycling, and alternative heat and electricity sources are also discussed.

AbstractOne important functional food ingredient today, valued for its health properties and ability to prevent disease, is bee pollen, which comprises a combination of nectar, pollen from plants, and the secretions of bees. In this research, the tyrosinase (TYR) inhibiting abilities of the peptides derived from bee pollen protein hydrolysates are investigated. Various proteases were utilized to generate these peptides, followed by testing at different concentrations. Tyrosinase inhibition activity was detected in all cases, while the hydrolysate drawn from 5.0% w/v neutrase exhibited the best IC50 value and was thus investigated further via ultrafiltration to separate the active fractions. The highest potential for tyrosinase inhibition was recorded for the fractions below 0.65 kDa. Subsequent purification steps via SEC and RP-HPLC led to the identification of the VDGYPAAGY (named VY-9) peptide via LC-Q-TOF-MS/MS in fraction F1–2, known for its non-toxic and hydrophobic characteristics albeit poor water solubility. The synthesized VY-9 peptide demonstrated competitive inhibition, with IC50 values of 0.55 ± 0.03 µM for mono-phenolase and 2.54 ± 0.06 µM for di-phenolase activities, as confirmed by molecular docking analysis revealing dominant hydrogen bond interactions with TYR. Effective concentrations of 0.2–1.6 µM of VY-9 showed negligible cytotoxicity in B16F10 cells. Melanin synthesis suppression was examined via qRT-PCR, and western blot in MITF, TYR, TRP-1, and TRP-2. Cell death in zebrafish embryos was evaluated in vivo using a toxicity assay which revealed no significant influence from VY-9, while anti-melanogenic effects were observed when the concentration was 4 µM, suggesting bee pollen-derived peptides’ potential in cosmetic and pharmaceutical depigmentation applications.

The polysaccharides found in Caulerpa lentillifera (sea grape algae) are potentially an important bioactive resource. This study makes use of RSM (response surface methodology) to determine the optimal conditions for the extraction of valuable SGP (sea grape polysaccharides). The findings indicated that a water/raw material ratio of 10:1 mL/g, temperature of 90 °C, and extraction time of 45 min would maximize the yield, with experimentation achieving a yield of 21.576 %. After undergoing purification through DEAE-52 cellulose and Sephacryl S-100 column chromatography, three distinct fractions were obtained, namely SGP11, SGP21, and SGP31, each possessing average molecular weights of 38.24 kDa, 30.13 kDa, and 30.65 kDa, respectively. Following characterization, the fractions were shown to comprise glucose, galacturonic acid, xylose, and mannose, while the sulfate content was in the range of 12.2–21.8 %. Using Fourier transform infrared spectroscopy (FT-IR) it was possible to confirm with absolute certainty the sulfate polysaccharide attributes of SGP11, SGP21, and SGP31. NMR (nuclear magnetic resonance) findings made it clear that SGP11 exhibited α-glycosidic configurations, while the configurations of SGP21 and SGP31 were instead β-glycosidic. The in vitro antioxidant assays which were conducted revealed that each of the fractions was able to demonstrate detectable scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cations. All fractions were also found to exhibit the capacity to scavenge NO radicals in a dose-dependent manner. SGP11, SGP21, and SGP31 were also able to display cellular antioxidant activity (CAA) against the human adenocarcinoma colon (Caco-2) cell line when oxidative damage was induced. The concentration levels were found to govern the extent of such activity. Moreover, purified SGP were found to exert strong inhibitory effects upon glycation, with the responses dependent upon dosage, thus confirming the potential for SGP to find a role as a natural resource for the production of polysaccharide-based antioxidant drugs, or products to promote improved health.

In this study, the AILQSYSAGKTK (named AK-12) peptide, also known as AK-12, from the Synechococcus marine microalgae cell extract is examined to determine the mechanism by which tyrosinase inhibition takes place. According to the docking simulation, it is expected that the peptides bind and interact at the tyrosinase active site, with the potential to support the inhibition of tyrosinase. For testing, the required peptides were first synthesized, before the results revealed tyrosinase inhibitory activity for which the respective IC50 values for mono- and di-phenolase activities were 489.71 +/- 0.01 mu M, and 765.57 +/- 0.01 mu M. The characteristics of the different competitive types were shown in a Lineweaver-Burk plot. For the treatment of B16F10 cells, peptide concentrations of 50-400 mu M were selected, confirming the absence of cytotoxicity. When the peptide was introduced, both tyrosinase activity and the production of melanin were significantly inhibited. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was then used to assess the suppression of melanin synthesis in MITF (microphthalmia-associated transcription factor, TYR (tyrosinase), TRP-1 (tyrosinase-related protein-1) and TRP-2 (tyrosinase-related protein-2). An in vivo toxicity assay was also carried out to evaluate zebrafish embryo cell death, revealing that AK-12 did not significantly affect cell death, while strong antimelanogenic activity was observed for the concentration of 50 mu M. From these findings it could be concluded that the peptide in question may offer potential in future hyperpigmentation treatments.

Hyperpigmentation often arises from an imbalance in melanogenesis, primarily due to the over- expression of tyrosinase (TYR). While the inhibition of TYR presents a common approach to skin whitening, it can lead to undesirable side effects. Thus, there is growing interest in safe and natural alternatives for TYR inhibition. Bioactive compounds and peptides sourced from split gill mushrooms hold promise in this regard. This study aims to optimize the conditions for papainmediated hydrolysis of split gill mushroom protein to inhibit TYR activity, utilizing response surface methodology (RSM) and central composite design (CCD). Optimal conditions were determined at a temperature of 46.70 degrees C, a hydrolysis time of 217.09 min, and an enzyme-to-substrate ratio (E/S) of 1.1%. Under these conditions, the resulting hydrolysates exhibited significant TYR inhibition, with an IC50 value of 117.86 mu g/mL and a degree of hydrolysis (DH) of 87.97%. Further purification via ultrafiltration and RP-HPLC yielded a peptide, Tyr-Ala-Ser-Ile-Leu-Leu (YASILL or YL-6), identified through LC-Q-TOF-MS/MS, which competitively inhibited TYR. YL-6 demonstrated an IC50 value of 3.97 mM for mono-phenolase activity and 6.75 mM for diphenolase activity. Molecular docking analysis revealed hydrogen bonds and hydrophobic interactions between TYR and YL-6. Treatment of B16F10 cells with YL-6 across concentrations ranging from 10-3000 mu M showed no cytotoxic effects.The inhibition of melanin synthesis was investigated via qRT-PCR along with Western blot in MITF, TYR, TRP-1, and TRP-2. The results obtained in this research may prove significant in guiding the development of commercially viable cosmetic products to whiten the skin.

This paper presents the initial exploration of the free radical scavenging capabilities of peptides derived from protein hydrolysates (PPH) obtained from Zingiber cassumunar rhizomes (Phlai). To replicate the conditions of gastrointestinal digestion, a combination of pepsin and pancreatin proteolysis was employed to generate these hydrolysates. Subsequently, the hydrolysate underwent fractionation using molecular weight cut-off membranes at 10, 5, 3, and 0.65 kDa. The fraction with a molecular weight less than 0.65 kDa exhibited the highest levels ABTS, DPPH, FRAP, and NO radical scavenging activity. Following this, RP-HPLC was used to further separate the fraction with a molecular weight less than 0.65 kDa into three sub-fractions. Among these, the F5 sub-fraction displayed the most prominent radical-scavenging properties. De novo peptide sequencing via quadrupole-time-of-flight-electron spin induction-mass spectrometry identified a pair of novel peptides: Asp-Gly-Ile-Phe-Val-Leu-Asn-Tyr (DGIFVLNY or DY-8) and Ile-Pro-Thr-Asp-Glu-Lys (IPTDEK or IK-6). Database analysis confirmed various properties, including biological activity, toxicity, hydrophilicity, solubility, and potential allergy concerns. Furthermore, when tested on the human adenocarcinoma colon (Caco-2) cell line, two synthetic peptides demonstrated cellular antioxidant activity in a concentration-dependent manner. These peptides were also assessed using the FITC Annexin V apoptosis detection kit with PI, confirming the induction of apoptosis. Notably, the DY-8 peptide induced apoptosis, upregulated mRNA levels of caspase-3, -8, and -9, and downregulated Bcl-2, as confirmed by real-time quantitative polymerase chain reaction (RT-qPCR). Western blot analysis indicated increased pro-apoptotic Bax expression and decreased anti-apoptotic Bcl-2 expression in Caco-2 cells exposed to the DY-8 peptide. Molecular docking analysis revealed that the DY-8 peptide exhibited binding affinity with Bcl-2, Bcl-xL, and Mcl-1, suggesting potential utility in combating colon cancer as functional food ingredients.