Unveiling the tyrosinase inhibitory potential of phenolics from Centaurium spicatum: Bridging in silico and in vitro perspectives.

Phenolics, abundant in plants, constitute a significant portion of phytoconstituents consumed in the human diet. The phytochemical screening of the aerial parts of Centaurium spicatum led to the isolation of five phenolics. The anti-tyrosinase activities of the isolated compounds were assessed through a combination of in vitro experiments and multiple in silico approaches. Docking and molecular dynamics (MD) simulation techniques were utilized to figure out the binding interactions of the isolated phytochemicals with tyrosinase. The findings from molecular docking analysis revealed that the isolated phenolics were able to bind effectively to tyrosinase and potentially inhibit substrate binding, consequently diminishing the catalytic activity of tyrosinase. Among isolated compounds, cichoric acid displayed the lowest binding energy and the highest extent of polar interactions with the target enzyme. Analysis of MD simulation trajectories indicated that equilibrium was reached within 30 ns for all complexes of tyrosinase with the isolated phenolics. Among the five ligands studied, cichoric acid exhibited the lowest interaction energies, rendering its complex with tyrosinase the most stable. Considering these collective findings, cichoric acid emerges as a promising candidate for the design and development of a potential tyrosinase inhibitor. Furthermore, the in vitro anti-tyrosinase activity assay unveiled significant variations among the isolated compounds. Notably, cichoric acid exhibited the most potent inhibitory effect, as evidenced by the lowest IC50 value (7.92 ± 1.32 µg/ml), followed by isorhamnetin and gentiopicrin. In contrast, sinapic acid demonstrated the least inhibitory activity against tyrosinase, with the highest IC50 value. Moreover, cichoric acid exhibited a mixed inhibition mode against the hydrolysis of l-DOPA catalyzed by tyrosinase, with Ki value of 1.64. Remarkably, these experimental findings align well with the outcomes of docking and MD simulations, underscoring the consistency and reliability of our computational predictions with the actual inhibitory potential observed in vitro.

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.

Chemical Profiling and Enzyme Inhibitory Activities of Essential Oil Isolated from Pistacia khinjuk Leaves: Insights On GC-MS Analysis and Skin Aging-Relevant Enzymes.

Pistacia khinjuk is a species of flowering plants belonging to family Anacardiaceae, with promising pharmacological activities like antioxidants, anti-inflammatory, antiviral, and antimicrobial. This study aimed to investigate the GC-MS chemical composition of essential oil isolated from Pistacia khinjuk leaves and its inhibitory properties against aging-relevant enzymes such a collagenase and elastase. The isolated oil showed predominance of ß-cadinene (15.34 %), γ-amorphene (8.50 %), α-cadinol (8.14 %), τ-cadinol (7.57 %), (E)-ß-caryophyllene (5.77 %), α-pinene (4.70 %), phytol (4.57 %), α-muurolene (3.30 %), (+)-epi-bicyclosesquiphellandrene (3.21 %), and cubenene (3.16 %). Further, it showed remarkable inhibitory activities against collagenase and elastase with IC50 values of 15.61±0.69 and 41.12±2.09 µg/mL, respectively compared to epigallocatechin gallate (IC50=29.52±1.3 µg/mL and 26.86±1.37 µg/mL). as a conclusion, the leaf oil is recommended for topical cosmetic preparations to retard skin aging symptoms such as wrinkles. However, the bioavailability assessment and toxicological profile should be considered in the future studies.

Screening of natural inhibitors against peptidyl arginine deiminase 4 from herbal extracts by a high-performance liquid chromatography ultraviolet-visible based method.

Peptidyl arginine deiminase 4 (PAD4) is an important biocatalytic enzymes involved in the conversion of protein arginine to citrulline, its dysregulation has a great impact on many physiological processes. Recently, PAD4 has emerged as a potential therapeutic target for the treatment of various diseases including rheumatoid arthritis (RA). Traditional Chinese Medicines (TCMs), also known as herbal plants, have gained great attention by the scientific community due to their good therapeutic performance and far fewer side effects observed in the clinical treatment. However, limited researches have been reported to screen natural PAD4 inhibitors from herbal plants. The color developing reagent (COLDER) or fluorescence based methods have been widely used in PAD4 activity assay and inhibitor screening. However, both methods measure the overall absorbance or fluorescence in the reaction solution, which are easy to be affected by the background interference due to colorful extracts from herbal plants. In this study, a simple, and robust high-performance liquid chromatography ultraviolet-visible (HPLC-UV) based method was developed to determine PAD4 activity. The proposed strategy was established based on COLDER principle, while used hydrophilic l-arginine instead of hydrophobic N-benzoyl-l-arginine ethyl ester (BAEE) as a new substrate to determine PAD4 inhibition activity of herbal extracts. The herbal extracts and PAD4 generated hydrophobic l-citrulline were successfully separated by the HPLC, and the developed method was optimized and validated with a known PAD4 inhibitor (GSK484) in comparison with COLDER assay. The IC50 value of GSK484 measured by HPLC-UV method was 153 nM, and the detection limit of the citrulline was 0.5 nmol, respectively, with a linear range of 0.5 nmol to 20 nmol. The IC50 value of the HPLC-UV method was improved by nearly three times compared with COLDER assay (527 nM), and the results indicated the reliability of PAD4 inhibition via HPLC-UV method. The inhibitory effect against PAD4 were fast and accurately screened for the twenty-four extracts from eight herbs. Among them, Ephedra Herba extracts showed significant inhibitory activity against the PAD4 with the IC50 values of three extracts (ethanol, ethyl acetate and water) ranging from 29.11 µg/mL to 41.36 µg/mL, which may help researchers to discover novel natural compounds holding high PAD4 inhibition activity.

In Vitro Determination of Nitric Oxide Synthase Inhibition, Antioxidant Capacity and Phenolic Content of Various Natural Products (Bee and Herbal Products).

It is obvious that the oxidation process is an undeniable fact and when it comes to aging, one of the first solutions that come to mind is natural products. When it comes to natural products, both plants and bee products play an important, almost combative role against oxidation. For this purpose, natural products of both plant and animal origin were considered together in our study: Linden, green tea, aronia, wild grapes, myrtle, blueberries and basil, honey, pollen and propolis. Total phenolic content values of the extracts ranged between 49.28 and 3859.06 mg gallic acid equivalent/100 g, and propolis, green tea, chestnut flower and aronia samples were found to have the highest values. When looking at the NOS inhibition potential, it was determined that propolis, pollen and aronia samples had the highest percentage inhibition values of 98.11, 92.29, 83.44, respectively. Antioxidant activities of methanolic extracts were investigated using iron(III) reducing/antioxidant capacity (FRAP), 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity test and NOS inhibition tests. The phenolic composition of methanolic extracts was tested using the RP-HPLC-UV (high-performance liquid chromatographic method with ultraviolet) method with 19 phenolic standards.

Identification of novel plant cysteine oxidase inhibitors from a yeast chemical genetic screen.

Hypoxic responses in plants involve Plant Cysteine Oxidases (PCOs). They catalyze the N-terminal cysteine oxidation of Ethylene Response Factors VII (ERF-VII) in an oxygen-dependent manner, leading to their degradation via the cysteine N-degron pathway (Cys-NDP) in normoxia. In hypoxia, PCO activity drops, leading to the stabilization of ERF-VIIs and subsequent hypoxic gene upregulation. Thus far, no chemicals have been described to specifically inhibit PCO enzymes. In this work, we devised an in vivo pipeline to discover Cys-NDP effector molecules. Budding yeast expressing AtPCO4 and plant-based ERF-VII reporters was deployed to screen a library of natural-like chemical scaffolds and was further combined with an Arabidopsis Cys-NDP reporter line. This strategy allowed us to identify three PCO inhibitors, two of which were shown to affect PCO activity in vitro. Application of these molecules to Arabidopsis seedlings led to an increase in ERF-VII stability, induction of anaerobic gene expression, and improvement of tolerance to anoxia. By combining a high-throughput heterologous platform and the plant model Arabidopsis, our synthetic pipeline provides a versatile system to study how the Cys-NDP is modulated. Its first application here led to the discovery of at least two hypoxia-mimicking molecules with the potential to impact plant tolerance to low oxygen stress.

New natural pro-inflammatory cytokines (TNF-α, IL-6 and IL-1ß) and iNOS inhibitors identified from Penicillium polonicum through in vitro and in vivo studies.

Overexpression of pro-inflammatory cytokines and iNOS have been found to be concomitant with several chronic inflammatory diseases and hence targeting their inhibition would be a useful therapy for inflammation. In view of this, study on discovery of natural pro-inflammatory cytokines inhibitory lead molecules from Penicillium polonicum, an endophytic fungus isolated from the fresh fruits of Piper nigrum was performed. When the culture broth extract of P. polonicum (EEPP) was subjected to LPS-induced cytokines expression (ELISA in RAW 264.7 cells), it exhibited inhibition of TNF-α, IL-6 and IL-1ß and this encouraged us to do chemical investigation on EEPP to explore the bioactive components. Four compounds isolated and characterised as 3,5-di-tert-butyl-4-hydroxy-phenyl propionic acid (1), 2,4-di-tert-butyl phenol (2), indole 3-carboxylic acid (3) and tyrosol (4) were tested for their effect on the production of TNF-α, IL-1ß and IL-6 in RAW 264.7 cells (ELISA). All the compounds exhibited a highly significant (P < 0.0001) inhibition effect, particularly against IL-1ß (IC50: 4-0.91 µM, 1-2.81 µM, 3-4.38 µM, and 2-5.54 µM). Tyrosol (4) was most active with IC50 values of 0.91, 2.67 and 4.60 µM against IL-1ß, IL-6 and TNF-α, respectively. On observing the potential activity of the compounds, two compositions C1 and C2 were prepared by mixing equimolar concentrations of compounds 1, 2, 3 & 4 (C1) and compounds 1, 2, 3, 4 & piperine (C2) in equal ratio. A synergistic effect was observed with C1 exhibiting potential suppression of IL-6 secretion (IC50 1.91 µM) and C2 against IL-1ß (IC50 5.98 µM). Also, the individual compounds and C1 were effective in controlling iNOS expressions in RAW 264.7 cells (RTPCR). Further, the in vivo performance of the compounds and compositions were studied under two in vivo inflammatory models (LPS-induced endotoxaemia and carrageenan-induced paw oedema). Compounds 1, 2, 3, 4, C1 and C2 at 50 mg/kg oral dose showed a significant control over the LPS-stimulated TNF-α, IL-1ß and IL-6 levels in plasma. C1, C2 and 1 exhibited > 50% pan-cytokine inhibition effect. Under the carrageenan-induced anti-inflammatory model, a significant reduction in the paw oedema measured in terms of the difference in the paw thickness was observed. Further, attenuation of pro-inflammatory cytokines levels following ELISA and RT-PCR experiments in the paw tissue homogenate was in agreement with paw thickness results. All compounds and C1 decreased the iNOS gene expression levels, and also the MPO activity and NO production in the paw tissue homogenate with tyrosol (4) as the most active molecule. Further, the mechanism of action was explored by testing the effect of the compounds on the expression of inflammatory markers using western blot analysis (in vitro). They were found to regulate the expression of pro-form and matured-form of IL-1ß by inhibiting NFκB. Also, the compounds reduced the translocation of the NF-κB subunit p65 to the nucleus. Thus, compounds 3,5-di-tert-butyl-4-hydroxy-phenyl propionic acid (1), 2,4-di-tert-butyl phenol (2), indole 3-carboxylic acid (3) and tyrosol (4) are reported as new natural multiple pro-inflammatory cytokines inhibitory leads. The interesting results of C1 might lay a footing for the development of a new anti-inflammatory composition.

Pharmacophore-driven identification of human glutaminyl cyclase inhibitors from foods, plants and herbs unveils the bioactive property and potential of Azaleatin in the treatment of Alzheimer's disease.

Alzheimer's disease (AD) is the leading cause of disabilities in old age and a rapidly growing condition in the elderly population. AD brings significant burden and has a devastating impact on public health, society and the global economy. Thus, developing new therapeutics to combat AD is imperative. Human glutaminyl cyclase (hQC), which catalyzes the formation of neurotoxic pyroglutamate (pE)-modified ß-amyloid (Aß) peptides, is linked to the amyloidogenic process that leads to the initiation of AD. Hence, hQC is an essential target for developing anti-AD therapeutics. Here, we systematically screened and identified hQC inhibitors from natural products by pharmacophore-driven inhibitor screening coupled with biochemical and biophysical examinations. We employed receptor-ligand pharmacophore generation to build pharmacophore models and Phar-MERGE and Phar-SEN for inhibitor screening through ligand-pharmacophore mapping. About 11 and 24 hits identified from the Natural Product and Traditional Chinese Medicine databases, respectively, showed diverse hQC inhibitory abilities. Importantly, the inhibitors TCM1 (Azaleatin; IC50 = 1.1 µM) and TCM2 (Quercetin; IC50 = 4.3 µM) found in foods and plants exhibited strong inhibitory potency against hQC. Furthermore, the binding affinity and molecular interactions were analyzed by surface plasmon resonance (SPR) and molecular modeling/simulations to explore the possible modes of action of Azaleatin and Quercetin. Our study successfully screened and characterized the foundational biochemical and biophysical properties of Azaleatin and Quercetin toward targeting hQC, unveiling their bioactive potential in the treatment of AD.

Rapid Screening of Lipase Inhibitors from Ophiopogonis Radix Using High-Performance Thin Layer Chromatography by Two Step Gradient Elution Combined with Bioautographic Method.

In this study, a high-performance thin layer chromatography (HPTLC) method by two step gradient elution with two mobile phases was developed for the simultaneous analysis of seven constituents in Ophiopogonis Radix. The chromatography was performed on silica gel 60 F254 plate with dichloromethane-methanol-ethyl acetate-water (70:25:12:3, v/v/v/v) and dichloromethane-methanol (300:1, v/v) as the mobile phase for two step gradient elution. Then, the HPTLC profiles were observed after derivatization with 10% sulfuric acid in ethanol solution. The obtained HPTLC images were further analyzed by chemometric approaches and the samples could be clustered based on regions and/or growth years, which were two important factors affecting the constituents in Ophiopogonis Radix. Furthermore, five compounds including ophiopogonin D, ophiopojaponin C, ophiopogonin D', ophiopogonin C' and methylophiopogonanone B were screened as potential lipase inhibitors from Ophiopogonis Radix by the HPTLC-bioautographic method. The binding modes and interactions between the five compounds and lipase were further explored by molecular docking analysis. The developed HPTLC method could be used for quality control of Ophiopogonis Radix and screening of the potential lipase inhibitors.

Development of Ultrasound-Assisted Extraction to Produce Skin-Whitening and Anti-Wrinkle Substances from Safflower Seed.

In this study, ultrasound-assisted extraction (UAE) was applied to extract bioactive substances with skin-whitening, anti-wrinkle, and antioxidant effects from safflower seeds, and the extraction conditions were optimized by a central composite design. The independent variables, including extraction time (5.0~55.0 min), extraction temperature (26.0~94.0 °C), and ethanol concentration (0.0~100%), were optimized to increase tyrosinase activity inhibitory (TAI), collagenase activity inhibitory (CAI), and radical scavenging activity (RSA), which are indicators of skin-whitening, anti-wrinkle, and antioxidant effects. An extraction time of 26.4 min, extraction temperature of 52.1 °C, and ethanol concentration of 50.7% were found to be optimum conditions of UAE, under which TAI, CAI, and RSA were 53.3%, 91.5%, and 27.7%, respectively. The extract produced by UAE was analyzed by LC-MS/MS, and maleic acid and levulinic acid were identified as the main substances. Therefore, UAE is evaluated as an effective process to extract skin-whitening, anti-wrinkle, and antioxidant substances from safflower seeds at lower temperatures and shorter extraction times compared to the conventional extraction methods. Overall, safflower seeds extract can be used as a material for value-added cosmetics, including maleic acid and levulinic acid, which have bioactive functions.

Comoclathrin, a novel potent skin-whitening agent produced by endophytic Comoclathris strains associated with Andalusia desert plants.

As part of our screening program for the discovery of molecules of microbial origin with skin-whitening activity, 142 diverse fungal endophytes from a wide variety of Andalusia arid plants were screened, applying the OSMAC approach. The fungal strains CF-090361 and CF-090766, isolated from xerophytic plants, were selected as the most promising, while phylogenetic analysis revealed that both strains could represent a new species within the genus Comoclathris. The effect of different fermentation conditions on the production of tyrosinase inhibitory activity was examined, in order to identify the optimum cultivation conditions. LCMS based metabolomics was applied to determine significant differences between the strains and fermentation conditions, and to identify potential bioactive secondary metabolites. Bioassay-guided purification of the main active components led to the isolation of three new compounds (1-3), along with the known compounds graphostrin B (4) and brevianamide M (5). Compound 1 (Comoclathrin) demonstrated the strongest anti-tyrosinase activity (IC50 0.16 µΜ), which was 90-times higher than kojic acid (IC50 14.07 µΜ) used as positive control. Additionally, comoclathrin showed no significant cytotoxicity against a panel of cancer cell lines (HepG2, A2058, A549, MCF-7 and MIA PaCa-2) and normal BJ fibroblasts. These properties render comoclathrin an excellent development candidate as whitening agent.

Lapcin, a potent dual topoisomerase I/II inhibitor discovered by soil metagenome guided total chemical synthesis.

In natural product discovery programs, the power of synthetic chemistry is often leveraged for the total synthesis and diversification of characterized metabolites. The synthesis of structures that are bioinformatically predicted to arise from uncharacterized biosynthetic gene clusters (BGCs) provides a means for synthetic chemistry to enter this process at an early stage. The recent identification of non-ribosomal peptides (NRPs) containing multiple ρ-aminobenzoic acids (PABAs) led us to search soil metagenomes for BGCs that polymerize PABA. Here, we use PABA-specific adenylation-domain sequences to guide the cloning of the lap BGC directly from soil. This BGC was predicted to encode a unique N-acylated PABA and thiazole containing structure. Chemical synthesis of this structure gave lapcin, a dual topoisomerase I/II inhibitor with nM to pM IC50s against diverse cancer cell lines. The discovery of lapcin highlights the power of coupling metagenomics, bioinformatics and total chemical synthesis to unlock the biosynthetic potential contained in even complex uncharacterized BGCs.

Comparison of chemical profiles, antioxidation, inhibition of skin extracellular matrix degradation, and anti-tyrosinase activity between mycelium and fruiting body of Cordyceps militaris and Isaria tenuipes.

CONTEXT: Cordyceps militaris and Isaria tenuipes (Cordycipitaceae) are high-value fungi that are used for health-promoting food supplements. Since laboratory cultivation has begun for these fungi, increased output has been achieved. OBJECTIVE: This study compared the chemical profiles, antioxidant, anti-tyrosinase, and skin extracellular matrix degradation inhibition between mycelium and fruiting body of C. militaris and I. tenuipes. MATERIALS AND METHODS: The antioxidative potential of 10% v/v aqueous infused extract from each fungus was separately investigated using 2,2-azinobis(3-ethylbenzo-thiazoline-6-sulphonic acid) (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant ability, and ferric thiocyanate methods. The inhibition against MMP-1, elastase, and hyaluronidase were determined to reveal their anti-wrinkle potential. Anti-tyrosinase activities were determined. RESULTS: C. militaris and I. tenuipes extracts were found to contain a wide range of bioactive compounds, including phenolics, flavonoids, and adenosine. A correlation was discovered between the chemical compositions and their biological activities. The extract from I. tenuipes fruiting body (IF) was highlighted as an extraordinary elastase inhibitor (IC50 = 0.006 ± 0.004 mg/mL), hyaluronidase inhibitor (IC50: 30.3 ± 3.2 mg/mL), and antioxidant via radical scavenging (ABTS IC50: 0.22 ± 0.02 mg/mL; DPPH IC50: 0.05 ± 0.02 mg/mL), thereby reducing ability (EC1: 95.3 ± 4.8 mM FeSO4/g extract) and lipid peroxidation prevention (IC50: 0.40 ± 0.11 mg/mL). IF had a three-times higher EC1 value than ascorbic acid and significantly higher elastase inhibition than epigallocatechin gallate. DISCUSSION AND CONCLUSIONS: IF is proposed as a powerful natural extract with antioxidant and anti-wrinkle properties; therefore, it is suggested for further use in pharmaceutical, cosmeceutical, and nutraceutical industries.

Anti-Proliferative and Anti-Telomerase Effects of Blackberry Juice and Berry- Derived Polyphenols on HepG2 Liver Cancer Cells and Normal Human Blood Mononuclear Cells.

BACKGROUND: Previous studies have provided strong evidence for the anticancer activity of berry fruits. OBJECTIVE: In this study, we investigated the effects of blackberry juice and three berry- polyphenolic compounds on cell proliferation and telomerase activity in human hepatoma HepG2 and normal peripheral blood mononuclear cells (PBMCs). METHODS: The cell viability and telomerase activity were measured by MTT and TRAP assay, respectively. Berry effects on the expression of genes were determined by quantitative RT-PCR assay. RESULTS: Blackberry, gallic acid, and resveratrol inhibited proliferation of both HepG2 and PBMC cells in a dosedependent manner. Resveratrol was more effective than gallic acid for reducing the viability of HepG2 cells, but both showed the same level of growth inhibition in PBMC cells. Berry, resveratrol, and gallic acid significantly inhibited telomerase activity in HepG2 cells. The antiproliferative effect of berry was associated with apoptotic DNA fragmentation. Gallic acid was more effective for reducing telomerase activity than resveratrol, but anthocyanin moderately increased telomerase activity in cancer cells. Telomerase activity was induced by all three polyphenols in PBMCs. Overall, Krumanin chloride was more effective to induce telomerase than gallic acid and resveratrol in PBMC cells. There was no significant difference in hTERT, hTR, and Dnmts expressions between berry treated and the control untreated HepG2 cells. But, a significant downregulation of HDAC1 and HDAC2 and upregulation of SIRT1 were observed in berry-treated cells. CONCLUSION: These data indicate that the berry anticancer effect is associated with antitelomerase activity and changes in HDACs expression. The data also suggest that berry antitelomerase activity is mainly related to its gallic acid and resveratrol, but not anthocyanin content.

Highly Potent Inhibition of Tyrosinase by Mulberrosides and the Inhibitory Mechanism in Vitro.

Many stilbene glycosides can alleviate skin hyperpigmentation due to their inhibitory effect on tyrosinase. Mulberrosides in Morus alba L. are stilbene glycosides. In the present study, the inhibition of tyrosinase by five mulberrosides (S1-5), isolated from Morus alba L. was investigated and compared, and the inhibitory mechanism was explored. These five mulberrosides exhibited obvious inhibitory effects on tyrosinase only in a concentration-dependent manner, without time-dependence, indicating that they are reversible inhibitors of tyrosinase. S2, S1 and S5 inhibited tyrosinase activity with IC50 values of 28.93, 75.94 and 151.72 µM, respectively, and were more active than kojic acid (IC50 =169.13 µM). Kinetic studies revealed that S1, S2 and S4 were competitive inhibitors, while S3 and S5 were mixed inhibitors. Analysis of the fluorescent spectra showed that mulberrosides S1, S2 and S4 quenched the intrinsic fluorescence intensity of tyrosinase. A molecular docking study indicated that the interaction of tyrosinase with mulberrosides was reflected by compound scores as follows: S2>S5>S1>S3/S4>kojic acid, and hydroxy groups in the side chain of mulberrosides may play a crucial role in the binding of the enzyme. Our results suggest that mulberrosides in Morus alba L. could be further developed as whitening agents for enhanced performance against hyperpigmentation.

Extracts from European Propolises as Potent Tyrosinase Inhibitors.

Tyrosinase is a key enzyme in the melanogenesis pathway. Melanin, the product of this process, is the main pigment of the human skin and a major protection factor against harmful ultraviolet radiation (UVR). Increased melanin synthesis due to tyrosinase hyperactivity can cause hyperpigmentation disorders, which in consequence causes freckles, age spots, melasma, or postinflammatory hyperpigmentation. Tyrosinase overproduction and hyperactivity are triggered by the ageing processes and skin inflammation as a result of oxidative stress. Therefore, the control of tyrosinase activity is the main goal of the prevention and treatment of pigmentation disorders. Natural products, especially propolis, according to their phytochemical profile abundant in polyphenols, is a very rich resource of new potential tyrosinase inhibitors. Therefore, this study focused on the assessment of the tyrosinase inhibitory potential of six extracts obtained from the European propolis samples of various origins. The results showed the potent inhibitory activity of all tested propolis extracts towards commercially available mushroom tyrosinase. The four most active propolis extracts showed inhibitory activity in the range of 86.66-93.25%. Apart from the evaluation of the tyrosinase inhibition, the performed research included UHPLC-DAD-MS/MS (ultra high performance liquid chromatography coupled with diode array detection and tandem mass spectrometry) phytochemical profiling as well as antioxidant activity assessment using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the 2,2"-azino-bis(3-ethylbenzothiazoline-6-sulfuric acid (ABTS) radical scavenging tests. Moreover, statistical analysis was used to correlate the tyrosinase inhibitory and antioxidant activities of propolis extracts with their phytochemical composition. To summarise, the results of our research showed that tested propolis extracts could be used for skin cosmeceutical and medical applications.

Chemical and Skincare Property Characterization of the Main Cocoa Byproducts: Extraction Optimization by RSM Approach for Development of Sustainable Ingredients.

Methylxanthines and polyphenols from cocoa byproducts should be considered for their application in the development of functional ingredients for food, cosmetic and pharmaceutical formulations. Different cocoa byproducts were analyzed for their chemical contents, and skincare properties were measured by antioxidant assays and anti-skin aging activity. Musty cocoa beans (MC) and second-quality cocoa beans (SQ) extracts showed the highest polyphenol contents and antioxidant capacities. In the collagenase and elastase inhibition study, the highest effect was observed for the SQ extract with 86 inhibition and 36% inhibition, respectively. Among cocoa byproducts, the contents of catechin and epicatechin were higher in the SQ extract, with 18.15 mg/100 g of sample and 229.8 mg/100 g of sample, respectively. Cocoa bean shells (BS) constitute the main byproduct due to their methylxanthine content (1085 mg of theobromine and 267 mg of caffeine/100 g of sample). Using BS, various influencing factors in the extraction process were investigated by response surface methodology (RSM), before scaling up separations. The extraction process developed under optimized conditions allows us to obtain almost 2 g/min and 0.2 g/min of total methylxanthines and epicatechin, respectively. In this way, this work contributes to the sustainability and valorization of the cocoa production chain.

StackHCV: a web-based integrative machine-learning framework for large-scale identification of hepatitis C virus NS5B inhibitors.

Fast and accurate identification of inhibitors with potency against HCV NS5B polymerase is currently a challenging task. As conventional experimental methods is the gold standard method for the design and development of new HCV inhibitors, they often require costly investment of time and resources. In this study, we develop a novel machine learning-based meta-predictor (termed StackHCV) for accurate and large-scale identification of HCV inhibitors. Unlike the existing method, which is based on single-feature-based approach, we first constructed a pool of various baseline models by employing a wide range of heterogeneous molecular fingerprints with five popular machine learning algorithms (k-nearest neighbor, multi-layer perceptron, partial least squares, random forest and support vectors machine). Secondly, we integrated these baseline models in order to develop the final meta-based model by means of the stacking strategy. Extensive benchmarking experiments showed that StackHCV achieved a more accurate and stable performance as compared to its constituent baseline models on the training dataset and also outperformed the existing predictor on the independent test dataset. To facilitate the high-throughput identification of HCV inhibitors, we built a web server that can be freely accessed at http://camt.pythonanywhere.com/StackHCV . It is expected that StackHCV could be a useful tool for fast and precise identification of potential drugs against HCV NS5B particularly for liver cancer therapy and other clinical applications.

Cardamonin Presents in Vivo Activity against Schistosoma mansoni and Inhibits Potato Apyrase.

Schistosomiasis, a neglected tropical disease caused by Schistosoma species, harms over 250 million people in several countries. The treatment is achieved with only one drug, praziquantel. Cardamonin, a natural chalcone with in vitro schistosomicidal activity, has not been in vivo evaluated against Schistosoma. In this work, we evaluated the in vivo schistosomicidal activities of cardamonin against Schistosoma mansoni worms and conducted enzymatic apyrase inhibition assay, as well as molecular docking analysis of cardamonin against potato apyrase, S. mansoni NTPDase 1 and S. mansoni NTPDase 2. In a mouse model of schistosomiasis, the oral treatment with cardamonin (400 mg/kg) showed efficacy against S. mansoni, decreasing the total worm load in 46.8 % and reducing in 54.5 % the number of eggs in mice. Cardamonin achieved a significant inhibition of the apyrase activity and the three-dimensional structure of the potato apyrase, obtained by homology modeling, showed that cardamonin may interact mainly through hydrogen bonds. Molecular docking studies corroborate with the action of cardamonin in binding and inhibiting both potato apyrase and S. mansoni NTPDases.

ß-Cyclodextrin Derivative Grafted on Silica Gel Represents a New Polymeric Sorbent for Extracting Nitisinone from Model Physiological Fluids.

Nitisinone (NTBC) is used in the treatment of disorders affecting the tyrosine pathway, including hereditary tyrosinemia type I, alkaptonuria, and neuroblastoma. An inappropriate dosage of this therapeutic drug causes side effects; therefore, it is necessary to develop a rapid and sensitive method to monitor the content of NTBC in patients' blood. This study aimed to develop anew polymeric sorbent containing ß-cyclodextrin (ß-CD) derivatives grafted on silica gel to effectively extract NTBC from model physiological fluids. The inclusion complex formed between ß-CD and NTBC was examined by proton nuclear magnetic resonance spectroscopy. The novel sorbents with derivatives of ß-CD were prepared on modified silica gel using styrene as a comonomer, ethylene glycol dimethacrylate as a crosslinking agent, and 2,2'-azo-bis-isobutyronitrile as a polymerization initiator. The obtained products were characterized via Fourier transform infrared spectroscopy and then used as sorbents as part of a solid phase extraction technique. High NTBC recovery (70%indicated that the developed polymeric sorbent may be suitable for extracting this compound from patients' blood samples.