Search Results (454)

Paradoxical hypertrichosis is an adverse effect of photo-epilation, involving the induction of hair growth within treated or adjacent non-treated areas. Given the significant psychosocial burden associated with facial hair growth in women, effective adjunctive strategies to mitigate this phenomenon are required. Chymotrypsin and papain are bioactive proteolytic enzymes whose activity has been associated with structural alterations in hair follicle components. This study investigated the effect of combining Alexandrite laser with enzyme-assisted hair removal compared with laser alone on the occurrence of paradoxical hypertrichosis. The outcome was assessed by recording the number of laser pulses performed per treatment session. Fifty-nine adult Greek women with facial hirsutism were allocated into two groups: Group I (Laser + Enzymes, n = 30), treated with Alexandrite laser (755 nm) combined with iontophoretic delivery of aqueous chymotrypsin and papain solutions, and Group II (Laser, n = 29), treated with laser alone. After 10 sessions, the combined intervention resulted in a significantly greater change in laser pulse counts compared with laser alone (−18.53 ± 16.31 vs. +1.68 ± 9.61, p < 0.005). This finding suggests that adjunctive iontophoresis of bioactive proteolytic enzymes is associated with reduced laser pulse requirements, which may be considered in the clinical management of paradoxical hypertrichosis in women with facial hirsutism. Larger studies with extended follow-up are warranted. Full article

This study compared the effectiveness of alkaline protease, neutral protease, trypsin, and papain in hydrolyzing oyster proteins and evaluated the antioxidant activities of the resulting hydrolysates. Alkaline protease achieved the highest degree of hydrolysis (30.96%) and the highest proportion of peptides ≤1 kDa (64.23%). Papain showed the lowest hydrolysis degree (18.29%). After separation by Sephadex G-15 gel filtration chromatography, the resulting low-molecular-weight peptide fractions (≤1 kDa) from each hydrolysate exhibited higher in vitro antioxidant activity than the higher-molecular-weight fractions (>1 kDa). Notably, trypsin and papain-derived low-molecular-weight fractions (OPP-T2 and OPP-P2) demonstrated stronger DPPH radical scavenging and inhibition of linoleic acid autoxidation than those from alkaline and neutral proteases. Cell experiments revealed that all low-molecular-weight fractions effectively alleviated H₂O₂-induced oxidative damage in LO2 cells. OPP-T2 and OPP-P2 exhibited significantly stronger protection of cell membrane integrity and enhancement of superoxide dismutase (SOD) activity than OPP-A2 and OPP-N2 (p < 0.05). OPP-T2 also showed the most pronounced increase in glutathione peroxidase (GSH-Px) activity (p < 0.05). These findings demonstrate that protease selection critically influences hydrolysis efficiency and antioxidant activity, with molecular weight being a key determinant of peptide antioxidant capacity. This work provides a reference for the development and application of oyster peptides. Full article

The SARS-CoV-2 papain-like protease (PL^pro) is an essential viral enzyme that promotes viral polyprotein processing while simultaneously suppressing the host innate immune response, which makes it a primary target for developing antiviral drugs. The present study employs a comprehensive approach integrating untargeted metabolomic profiling, in silico molecular docking and dynamics simulations, Molecular Mechanics Generalized Born Surface Area (MM-GBSA) energetic assessments, and biochemical enzyme assays. This integrated method aims to discover natural PL^pro inhibitors from two ethnomedicinal plants, Lippia javanica and Acorus calamus, which have long been utilized in African traditional medicine to treat respiratory diseases. Comprehensive metabolite profiling using untargeted Ultra-Performance Liquid Chromatography–Tandem Mass Spectrometry (UPLC-MS/MS) and Global Natural Products Social (GNPS) molecular networking revealed flavonoid glucuronides and phenylpropanoid derivatives as the major constituents in both plant species. In situ histochemical staining further offered spatial validation of phenolic- and lignin-associated tissues, supporting the phenolic-dominated molecular families detected by GNPS molecular networking. In silico evaluation of six selected compounds demonstrated spontaneous and thermodynamically favorable binding to PL^pro, with ΔG_bind values ranging from −5.63 to −6.43 kcal/mol. Catechin-7-glucoside emerged as the lead compound, establishing multiple hydrogen bond networks with Asp164, Gln269, Tyr264, and Asn267, supplemented by hydrophobic engagement with Pro247 and Pro248, and π-π stacking with the blocking loop 2 (BL2 loop). Molecular dynamics simulations confirmed the stability of the protein–ligand complexes. Biochemical enzyme assays confirmed concentration-dependent inhibition of PL^pro proteolytic and deubiquitinating activity by both crude plant extracts and isolated bioactive compounds. However, S-adenosyl-methionine showed comparatively high PL^pro proteolytic activity (IC₅₀ 5.872 µM) compared to catechin-7-glucoside, with an IC₅₀ of 7.493 µM, exhibiting efficacy similar to the reference inhibitor GRL0617. Both the extracts of L. javanica and A. calamus have shown significant inhibitory activity while maintaining cell viability in Human embryonic kidney 293T cell (HEK293T) culture models, indicating a favorable safety profile of the tested concentrations. Based on these results, catechin-based polyphenols and phenylpropanoid derivatives appear as promising lead compounds for the development of PL^pro inhibitors. To progress toward therapeutic use, further work is necessary in pharmacokinetics, structural optimization, and antiviral validation in cell models. Full article

Haliotis discus hannai meat has a firm texture that makes it difficult to chew and swallow, so tenderizing is necessary. Ultrasonic treatment and papain enzyme processing are used to reduce the hardness of abalone meat. This study tests physicochemical indicators and protein changes to assess meat quality and protein alterations. The maximum reduction in hardness of raw meat reached 60.58%, while heat-treated abalone meat achieved 61.13%, with free water and bound water converting to immobile water. The L* value of the meat decreased, while the a* and b* values increased. In raw meat, the content of TCA-soluble peptides increased with increasing treatment intensity. However, in heat-treated meat, this peptide content decreased with rising temperature. Muscle fiber filament breaks and pore numbers increased. The BPB binding content showed a negative correlation with the percentage of α-helix. Total sulfhydryl and free amino groups in raw meat decrease with increasing treatment intensity; both parameters in cooked meat decrease with rising temperature. Changes in tertiary protein structure cause alterations in fluorescence intensity, with secondary structure shifting from α-helix to β-sheet conformation. The results suggested that ultrasonic and papain treatments can induce structural alterations in proteins. This leads to protein cleavage and depolymerization, collectively resulting in softening of abalone meat texture and redistribution of internal moisture. These processes result in softening of abalone meat and redistribution of internal moisture. This study provides a theoretical basis for developing abalone tenderizers. Full article

Hypertension is a globally prevalent chronic cardiovascular disease, with angiotensin-converting enzyme (ACE) serving as a key target for therapeutic intervention. Synthetic ACE inhibitors have side effects, making natural food-derived ACE-inhibitory peptides a research hotspot owing to safety advantages. Softshell turtle (Pelodiscus sinensis) bone collagen (STBC) has potential bioactivity, but its ACE-inhibitory peptides have not been systematically investigated. This study used computer-aided screening: STBC α1(I) (K7FHL1) and α2(I) (K7G8R1) sequences from UniProt were processed via SignalP 5.0. BIOPEP-UWM analysis showed ACE-inhibitory peptide frequencies of 0.8947 and 0.9261 in the two chains, confirming STBC as a high-quality precursor. Papain-ficin was selected as the optimal enzymatic system via simulation; 105 potential novel peptides were obtained after toxicity/allergenicity prediction. Twenty-seven highly active peptide fragments were screened out via pLM4ACE, and four peptide fragments with relatively high binding energy (QICVCDS, DVWK, IIEY, APMDVG) were identified through molecular docking. These peptides (molecular weight: 536.6–766.9 Da) possessed excellent physicochemical properties and pharmacokinetic characteristics, while bioinformatics analysis revealed that they could target and regulate SRC/HSP90AA1 to modulate the renin-angiotensin system (RAS). This study provides an efficient strategy for the high-value utilization of softshell turtle resources and the development of food-derived ACE-inhibitory peptides. Full article

New aminonitrocyclitols were directly synthesized through stereoselective, one-pot, multistep cascade reactions. The aminonitrocyclitol moiety was constructed by the sequential action of two enzymes followed by a spontaneous intramolecular Henry reaction. To construct the carbocycle, two C–C bonds were stereoselectively cleaved, one by aldolase and the other by the intramolecular nitroaldol reaction. The aldolase acceptor substrates were generated by adding an amino group to 4-nitrobutanal. As expected, only the (R,R)- or d-erythroaldol configuration was obtained with l-fuculose-1-phosphate aldolase (F1PA). In the case of l-rhamnulose-1-phosphate aldolase (R1PA), both the aldol (R,S)- or l-threo and erythroaldol (R,R)- or d-erythroaldol configurations were obtained in very close ratios. The presence of a ketone and a terminal nitro group in the aldol formed led to a stereoselective intramolecular Henry reaction. The various aminonitrocyclitols were obtained in amide form with an average overall yield of 60%. Deprotection of the amine function was achieved by hydrolysis of the amide group by the action of papain without epimerization at the ring carbon stereochemistries defined in the previous steps. All these reactions led to the preparation of new aminonitrocyclitols with high stereoselectivity. Full article

Papain-like protease (PLpro), a crucial functional domain of the SARS-CoV-2 non-structural protein 3 (nsp3), plays a dual role in both hydrolyzing viral polyprotein precursors and modulating host immune responses. These critical functions position PLpro as a key target in the ongoing development of antiviral therapies for SARS-CoV-2. This review analyzes more than 100 PLpro-ligand co-crystal structures and summarizes the major binding modes between these ligands and PLpro. Most of these ligands bind to sites analogous to those targeted by the classical non-covalent inhibitor GRL0617, primarily involving the P3 and P4 subsites and the BL2 loop. Based on these structural insights, optimized inhibitors have expanded targeting beyond the canonical binding site to auxiliary regions such as the BL2 groove and the Val70 site, and in some cases toward the catalytic Cys111 buried within a narrow pocket. Certain ligands identified through various screening approaches bind to non-canonical or allosteric regions, such as the S1 and S2 sites or the zinc-finger domain, engaging PLpro through distinct interaction modes and thereby offering additional opportunities for PLpro inhibitor design. The review also discusses potential strategies for future PLpro inhibitor development informed by recent structural advances. Taken together, these structural and functional insights support ongoing efforts in the structure-guided design and optimization of PLpro inhibitors. Full article

This study examined the impact of enzymatic tenderization on Cornu aspersum aspersum snail meat using mechanical texture analysis, SDS-PAGE (sodium dodecyl sulfate–polyacrylamide gel electrophoresis) protein profiling, and sensory evaluation. Samples were treated with papain (0.05–0.1%), bromelain (0.05–0.1%), or 10–25% ginger extract containing zingibain and subsequently hydrothermally processed. All enzymatic treatments significantly reduced shear force compared with the control (p < 0.05). The lowest connective tissue resistance (S1) was observed for 0.1% bromelain (14.1 N) and 10% ginger extract (19.0 N), versus >21 N in untreated samples. SDS-PAGE revealed that bromelain caused extensive degradation of high-molecular-weight proteins (>90 kDa), whereas papain induced moderate myofibrillar proteolysis. Higher concentrations of bromelain (0.1%) and ginger extract (25%) resulted in excessive softening and structural disintegration, leading to sensory disqualification. Sensory evaluation showed that moderate enzyme concentrations significantly improved overall acceptability (p < 0.05). Samples treated with 10% ginger extract achieved the highest overall sensory score (4.6/5), exceeding the control (3.9) and papain- or bromelain-treated samples (4.1–4.2). In conclusion, although bromelain exhibited the strongest proteolytic activity, a 10% ginger extract was identified as the optimal treatment, providing effective tenderization while preserving structural integrity and sensory quality. Full article

Despite growing interest in South African medicinal plants, advanced metabolomic workflows that integrate positive (ESI+) and negative (ESI−) ionization modes in UPLC-MS/MS remain sparsely applied to South African flora, and especially to Acorus calamus and Lippia javanica species. Herein, application of a dual-polarity (positive (ESI+) and negative (ESI−) ionization modes) using an untargeted UPLC–MS/MS workflow, integrated with HEK293T cytotoxicity screening, to map their metabolomes, and rank potential signature metabolites for targeted antiviral follow-up. SwissADME supported in silico drug-likeness. Neither plant extract was cytotoxic across the concentration range, with absorbance-based cell viability of 73.82% for L. javanica and 77.23% for A. calamus at 250 µg/mL, and fluorescence-based cell viability ≥59.87% and ≥55.89%, respectively. Dual-polarity expanded coverage with ESI− yielded 312 features, compared with 225 with ESI+, consistent with the predominance of acidic phenolics in plant species. Unsupervised and supervised models segregated the plant species (PCA PC1/PC2 variance: ESI+ 89.4%/3.0%; ESI− 93.5%/1.8%; R²X(cum) = 0.799). Differential analysis identified 118 significant features in ESI+ with 80 up-regulated, 38 down-regulated, and 139 in ESI− with 96 up-regulated, 43 down-regulated. The ESI− showed the wider dynamic range. Chemotypes enriched among significant metabolites include flavonols of 3-O-methylkaempferol, apigenin, and conjugates of Pollenin A, iridoid glycosides of oleoside, forsythoside B, and jasmonate-pathway oxylipins of 7-epi-12-hydroxyjasmonic acid and its glucoside. These also include caryoptosidic acid and catechin-7-glucoside, which are ionized in both modes, pinning the increase in biomarker robustness. In conclusion, a dual-mode UPLC–MS/MS approach, integrated with cytotoxicity exploration, delivers a complementary metabolome coverage and a safety awareness for shortlisting of potential signature metabolites from L. javanica and A. calamus. Moreover, in vitro inhibition of SARS-CoV-2 papain-like protease (PL^pro) by these plants links chemical signatures to antiviral relevance. Shortlisted significant metabolites that demonstrated favorable drug-likeness include flavonol scaffolds of 3-O-methylkaempferol, Pollenin A, and jasmonate-pathway derivatives of 7-epi-12-hydroxyjasmonic acid. Moreover, the dual ionization mode may eliminate ionization bias, broaden metabolome coverage, and yield a mechanism-ready shortlist of metabolites from South African medicinal plants for downstream antiviral investigation. Full article

The use of proteolytic enzymes in association with entomopathogenic fungi offers a promising alternative for improving the biological control of insect pests. This study evaluated the compatibility between Beauveria bassiana and papain and the effectiveness of their combined application in controlling Tenebrio molitor. Conidial viability in the presence of papain was monitored for 48 h and showed a reduction in germination from 100% to approximately 70%, without detrimental effects on fungal performance. Papain activity remained stable up to 12 h, declining afterward, indicating biochemical compatibility. Bioassays revealed significant differences among treatments (p < 0.01). In larvae, mortality ranged from 5.18 ± 0.19% in the control to 49.62 ± 2.00% with papain, 62.24 ± 0.58% with conidia, and 89.71 ± 1.06% in the combined treatment; papain and conidia alone did not differ statistically. In pupae, mortality reached 2.20 ± 0.00% in the control, 47.38 ± 0.69% with papain, 63.69 ± 0.69% with conidia, and 85.91 ± 0.84% with the combination, with all treatments differing significantly. Fungal reisolation confirmed typical B. bassiana development. Overall, the results show that papain does not compromise fungal viability and that its combination with B. bassiana enhances entomopathogenic activity, supporting its potential for integrated pest management. Full article

Pseudomonas extremorientalis PEY1, isolated from the intestinal contents of marine fish, was evaluated for the production and properties of antibacterial proteins active against Edwardsiella tarda, a major pathogen in aquaculture. Antibacterial production was maximized in a minimal medium supplemented with 1% yeast extract and 1% galactose under stationary cultivation at 25 °C and pH 7.0. Growth and bioactivity assays were conducted under varying carbon and nitrogen sources, temperatures, and pH levels. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed a distinct ~37 kDa protein band corresponding to antibacterial activity, exhibiting an inhibition zone of 2.4 ± 0.1 cm against E. tarda. The activity was completely abolished by papain digestion but remained detectable after exposure to 55 °C and pH 8, indicating that the active compound is a moderately heat-stable, proteinaceous antibacterial molecule. LC–MS/MS analysis identified the protein as a putative disulfide reductase with ~40% sequence coverage. The antibacterial factor exhibited strong physicochemical stability, retaining activity in the presence of surfactants and metal ions. Collectively, these findings demonstrate that P. extremorientalis PEY1 produces a thermostable, papain-sensitive antibacterial protein with selective activity against E. tarda, highlighting its potential as a promising natural biocontrol or postbiotic candidate for sustainable aquaculture. Full article

The liquid egg processing industry generates a significant amount of solid byproduct known as chalaza (CHA), which is rich in sialic acid and exhibits notable biological activity. In this study, the preparation process, N-glycan profile, and skin-whitening activity of CHA-derived glycopeptides (CHAH) were investigated. By comparing the hydrolysis efficiency of trypsin, alcalase, and papain, a dual-enzyme hydrolysis strategy was developed: initial hydrolysis with 1.5% trypsin for 3 h, followed by treatment with 1% papain for 2 h. The resulting CHAH exhibited both a high hydrolysis yield and strong antioxidant activity. The sialic acid content in CHAH reached 1.96% (w/w), and 14 distinct N-glycan chain structures were identified. The whitening effect of CHAH was assessed using a combined approach involving an in vitro B16 cell model and an in vivo zebrafish model. CHAH was found to inhibit tyrosinase activity and reduce melanin production in a concentration-dependent manner. Mechanistic studies revealed that CHAH acts by significantly downregulating the expression of key genes involved in melanin synthesis, including MITF, TYR, TYRP1, and TYRP2. This study establishes an efficient preparation method for CHAH, elucidates its skin-whitening efficacy and underlying mechanism, and provides experimental support for the potential industrial application of CHAH as an active ingredient in skincare products. Full article

To enhance the antibacterial properties of chitosan, this study employed papain as a biocatalyst to graft nisin onto chitosan, yielding two grafted products with grafting ratios of 8.56% (Ni1-Cs) and 14.35% (Ni2-Cs). Structure analyses confirmed the formation of amide bonds. Grafting significantly improved the solubility (92.4%), water absorption (53.4%), and film-forming properties of chitosan, with Ni1-Cs films achieving a tensile strength of 25.2 MPa. Antibacterial assays demonstrated that nisin retained favorable activity post-grafting and exhibited synergistic effects with chitosan. The minimum inhibitory concentrations (MIC) of Ni2-Cs against Escherichia coli and Staphylococcus aureus were 132.4 and 97.4 μg/mL, respectively, significantly superior to individual components. The ultra-low-temperature enzymatic method likely preserved nisin’s structural integrity. Mechanistic studies revealed that the cationic nature of chitosan and the pore-forming mechanism of nisin synergistically disrupted bacterial cell membranes. Sea bass preservation trials confirmed that Ni2-Cs coatings effectively retarded quality deterioration, inhibited microbial growth and lipid oxidation, and maintained freshness for 15 days. This study demonstrates that the ultra-low-temperature enzymatic strategy successfully prepared nisin-grafted chitosan materials with synergistic antibacterial effects, showing promising applications for food preservation. Full article

Oxidative stress is related to cellular damages and aging. Bioactive peptides have the potential to be a useful functional ingredient, although Bangia fuscopurpurea (red alga), a dense protein source, has not yet been exploited as a source of antioxidant peptide. The aim of the study was to prepare, isolate, and characterize antioxidant peptide of B. fuscopurpurea and assess their protection against oxidative stress in vitro, in HepG2 cells, and in Caenorhabditis elegans. Protein of B. fuscopurpurea was subjected to hydrolysis with papain and purification of the hydrolysate was performed through multi-step chromatography and ultrafiltration. The LC-MS/MS identified peptides, which were synthesized and screened. Two new peptides, YPCW and GYPYK, were discovered and both of them had strong antioxidant properties in vitro, with the ABTS radical scavenging IC₅₀ of 2.52 ± 0.37 µg/mL and ORAC of 5187 ± 78 µmol TE/g. Both peptides in H₂O₂-induced HepG2 cells significantly decreased the intracellular ROS and MDA and inhibited the activity of antioxidant enzymes (SOD, CAT, and GSH-Px). Moreover, YPCW and GYPYK increased the survival of C. elegans during oxidative stress and the similar response, altering antioxidant enzyme activities in vivo and MDA levels. These findings indicate that peptides obtained through B. fuscopurpurea can be useful as antioxidant agents, and they can be considered as a possible new active ingredient of functional foods or pharmaceuticals to counteract oxidative stress. Full article

Minimally invasive treatment is increasingly successful in managing carious lesions in primary teeth, owing to the regenerative capacity of the dental pulp and the possibility to influence the pulp–dentin complex. Chemo-mechanical caries excavation (CME) with Brix 3000, a papain-based enzymatic agent, allows selective removal of infected dentin while preserving affected dentin for potential remineralization. Fluorescence-aided caries excavation (FACE) enables visualization of porphyrins produced by cariogenic microorganisms, guiding selective dentin removal. In this study, 42 children aged 4–7 years with ICDAS II code 05–06 lesions in primary molars were treated, and the correlation between fluorescence intensity and cariogenic microbial load was evaluated. CME was performed using Brix 3000, and residual dentin was categorized by fluorescence as red, red with pale-pink areas, pale-pink, or non-fluorescent. Microbiological samples were collected pre- and post-excavation, cultured under standardized laboratory conditions, and quantitatively analyzed. Results showed that higher fluorescence intensity corresponded to increased presence of S. mutans (ρ = 0.945, p < 0.001), while other species were present in lower quantities. CME with Brix 3000 significantly reduced microbial load, and fluorescence reliably indicated areas requiring removal. These findings demonstrate that combining FACE with Brix 3000 allows precise, minimally invasive caries removal in primary teeth, providing an objective method to guide tissue-preserving excavation while effectively controlling cariogenic microorganisms. Full article