Significant Tyrosinase Inhibitory Activity Research Articles

Inhibitory mechanism on tyrosinase activity of flavonoids from flower buds of Sophora japonica L

The flower buds of Sophora japonica L. (FBSJ) have long been applied as Traditional Chinese Medicine (TCM) and functional food in East Asia. In this study, extracts of FBSJ from 11 different locations were analyzed using the HPLC method to establish their HPLC fingerprints. By determining the IC50 on tyrosinase activity, it was discovered that the extract from Kunming, Yunnan Province exhibited the strongest inhibitory activity. Further analysis, including partial least squares regression coefficient analysis and grey correlation analysis, regarded kaempferol, isorhamnetin, and quercetin as the compounds with significant tyrosinase inhibitory activities. To understand the inhibition mechanism of tyrosinase activity, various analytical techniques such as enzymatic kinetic analysis, fluorescence quenching, circular dichroism (CD), molecular docking, and molecular dynamics simulation were employed. The results revealed that quercetin, isorhamnetin, and kaempferol exhibited higher inhibitory activity and binding energy compared with kojic acid, indicating their potential value as natural tyrosinase inhibitors. This research provides a solid theoretical foundation for studying the application and mechanism of flavonoids against tyrosinase in FBSJ.

Discovery of superior bioactive peptides of two edible Lentinus mushrooms protein hydrolysate in biological activities: tyrosinase inhibitory and antioxidant activity.

This study investigated protein hydrolysates obtained from Lentinus squarrosulus and Lentinus edodes fruiting bodies via gastric protease hydrolysis and ultrafiltration, yielding peptides with a molecular weight below 6.5kDa. These hydrolysates displayed significant tyrosinase inhibitory activity similar to positive controls, peptide from Chinese quince seed (RHAKF) and kojic acid. L. squarrosulus-derived hydrolysates exhibited superior antioxidant properties compared to L. edodes in DPPH (47% vs. 23%) and ABTS (77% vs. 23%) assays. Identified bioactive peptides, particularly LILGGSSS from L. squarrosulus, interacted with tyrosinase through hydrogen bonds at specific residues. Notably, these protein hydrolysates showcased potent tyrosinase inhibition without cytotoxic effects, presenting promising prospects for addressing hyperpigmentation caused by excessive tyrosinase activity from stress or UV exposure.

Enzyme-Assisted Extraction of Fucosylated Chondroitin Sulfate from Sea Cucumber Holothuria scabra and Bohadschia argus and their Potential in Pharmaceutical Applications

Due to the health benefit of fucosylated chondroitin sulfate (FuCS), the efficient method for extraction of FuCS from raw materials is a crucial issue in reducing the production cost. In this study, enzymatic extraction of FuCS from two species of sea cucumber, Holothuria scabra and Bohadschia argus was undertaken using two protease enzymes, alcalase and papain. Response surface methodology (RSM) was employed in determining the optimal extraction conditions with the highest yield of FuCS concentration. The predicted optimal papain-assisted extraction conditions of Holothuria scabra and Bohadschia argus obtained a predicted FuCS yield of 1609.73 mg/100 g and 444.51 mg/100 g, respectively. To compare extraction efficiencies of two protease enzymes, employment of the RSM optimal conditions to Holothuria scabra resulted in 1538.76 ± 20.26 mg/ 100 g and 1295.50 ± 14.28 mg/100 g of purified FuCS for papain and alcalase, respectively. Whereas Bohadschia argus produced 412.39 ± 10.12 mg/100 g and 461.11 ± 8.45 mg/100 g purified FuCS for papain and alcalase, respectively. The acquired FTIR and NMR spectrums of extracted FuCS showed typical bands of sulfation patterns and were compared to commercial FuCS. The extracted FuCS showed enzyme type dependent antioxidant activity, and significant tyrosinase inhibitory activity than commercial FuCS. It also exhibited similar anti-glucosidase activity as commercial FuCS. Thus, this study reveals potential applications of enzyme-assisted FuCS from sea cucumber in food and pharmaceutical industries.

A Perusal of Phenolics Within Polar Peel Fractions of Malus domestica var Maharaji via Hyphenated Techniques Cum Anti-microbial with REMA and Tyrosinase Inhibitory Potential thereof

This study aims to scrutinize the phenolic secondary metabolites in the polar peel decocture of Malus domestica var Maharaji via hyphenated techniques along with the study of the antibacterial, anti-candida, and tyrosinase inhibitory potential of bioactive compound-rich fractions. Preliminary phenolics go over was performed together with thin layer chromatography before the polar decocture was subjected to hyphenated techniques. FTIR investigation revealed the C-O bonds as in phenols, O-H bond stretch, and vibrations of alcohols and carboxylic acids as well as portrayed the C-H and >C=O stretches among other functional groups all of which are representative of phenolic and polyphenolic compounds. GC-MS perusal demonstrated the presence of bioactive compounds like Quercetin (13.04%), Ascorbic acid (6.48%), p-Coumaric acid (6.17%), Caffeic acid (5.69 %), Mallic acid (5.44%), Apigenin (5.28%), Citric acid (5.15%), Gallic acid (4.38%), Cyanidin (3.52%), and Ferulic acid (3.51%). Kirby-Bauer method followed by the resazurin microtiter assay technique (REMA) for MIC/MBC against six MTCC bacterial strains and one yeast, all producing stubborn opportunistic infection in humans, was used to assess the antibacterial property of all the bioactive rich fractions. Some fractions comparatively revealed a good activity index (AI) against tested microbes. MIC concentrations for bacteria ranged from 15-24 mg/ml while a lower MBC value recorded was 18 mg/ml. Methanol fraction revealed significant tyrosinase inhibitory activity by revealing IC50 of 980.98 µg/ml when L-Tyrosine was substrate and IC50 of 830.68 µg/ml when L-DOPA was substrate when juxtaposed to standard kojic acid that revealed IC50 of 128.822 µg/ml when L-Tyrosine was substrate and IC50 of 149.43 µg/ml when L-DOPA was substrate. The bioactive compounds possessed by the fractions, may be synergistically, turned out to be more effective in the diphenolase reaction and kojic acid acts more effectively in the monophenolase one. It was inferred that peel phenolics of this malus variety have a lot of therapeutic potential in the context of bacterial infections and pigmentation disorders.

Relative Free Radical Scavenging, Tyrosinase Inhibitory, and Anti-Inflammatory Potential of the Polar Peel decoctures of distinct Malus Species indigenous to Kashmir

Apple, (Malus domestica, Brokh), is a vital source of phenolic and polyphenolic compounds whose accumulation in the different parts of the fruit depends upon various intrinsic and extrinsic factors. This study aimed to perform a comparative evaluation of phenolics of peels of three red-skinned (“Delicious”, “Maharaji”, “Royal delicious”), and one yellow-skinned (“Golden Delicious”) apple varieties incorporating preliminary secondary metabolite perusal followed by estimation of Total phenol and total flavonoid contents. Secondary phytocompounds being usually polar in nature were extracted from peels via the Soxhlet and hot maceration processes using different menstruum systems of varied polarity. Comparative assessment of Free radical scavenging, anti-pigmentation, and anti-inflammatory properties of all the decoctures was analyzed thereafter.Free radical scavenging capacity was analyzed via 2, 2-diphenyl-1-picrylhydrazyl assay.Tyrosinase inhibitory activity was assessed by studying the in vitro impact of decoctures on the monophenolase and diphenolase reactions of the enzyme tyrosinase. The anti-inflammatory potential of the samples was assessed by inhibition of hypotonicity-induced HRBC membrane lysis. TPC/TFC estimation was analyzed via spectrophotometry. Methanol crude peel extracts of all apple species revealed rich phytochemical content as per TPC/TFC analysis. In a dose-dependent manner, all the crude peel extracts demonstrated considerable free radical scavenging capacity with DPPH assay. Maharaji methanolic decocture revealed potent free radical scavenging activity by showing the lowest IC50 value while Royal delicious acetone extract showed the highest IC50 value when collated with the potent reference antioxidant ascorbic acid with an IC50value of 114.62µg/ml. Polarextract of Malus domestica var Maharaji revealed significant tyrosinase inhibitory activity by revealing IC50 of 8460.65µg/mlon L-Tyrosine substrate and IC50 of 7830.46 µg/ml on L-DOPA substrate. Malus peel compounds turn out to be more effective in diphenolase reaction and kojic acid acts more effectively in the monophenolase one.At various concentrations, the percentage of membrane stabilization for methanolic extracts and the reference NSAID diclofenac sodium was determined.The highest level of membrane stabilization wasshown by methanolic Maharaji and delicious apple peel extracts (83.76 % and 72.32% at a dose of 200 mg/ml respectively) when juxtaposed with standard NSAID showing 98.58 % inhibition at a concentration of 25 mg/ml. Methanol extracts of Malus domestica var Maharaji out performed the other Malus peel extracts in terms of all the parameters analyzed, according to the current study. So, this study is giving the highest pharmaceutical priority to the Malus domestica var Maharaji when it comes to human-health benign bioactive compounds, oxidative stress-related diseases, pigmentation disorders, and inflammatory diseases.

Tyrosinase Inhibitory Peptides from Enzyme Hydrolyzed Royal Jelly: Production, Separation, Identification and Docking Analysis.

Tyrosinase is inextricably related to the development of Alzheimer's disease. The effects of natural tyrosinase inhibitors on human health have attracted widespread attention. This study aimed to isolate and analyze the tyrosinase (TYR) inhibitory peptides in the enzymatic digestion products of royal jelly. We first analyzed optimal process conditions for the enzymatic digestion of royal jelly by single-factor and orthogonal experiments and then used gel filtration chromatography to obtain five fractions (D1~D5) with molecular weights ranging from 600 to 1100 Da. LC-MS/MS was applied to identify the fractions with the highest activity, and the obtained peptides were screened and molecularly docked using AutoDock Vina. The results showed that the optimal enzymatic conditions for tyrosinase inhibition rate were acid protease, enzyme addition 10,000 U/g, initial pH 4, feed-to-liquid ratio 1:4, enzymatic temperature 55 °C, and enzymatic time 4 h. The D4 fraction had the most significant TYR inhibitory activity. The IC50 values of the three new peptides with the strongest TYR inhibitory activity, TIPPPT, IIPFIF, and ILFTLL, were obtained as 7.59 mg/mL, 6.16 mg/mL, and 9.25 mg/mL, respectively. The molecular docking results showed that aromatic and hydrophobic amino acids were more favorable to occupy the catalytic center of TYR. In conclusion, the new peptide extracted from royal jelly has the potential to be used as a natural TYR inhibitory peptide in food products with health-promoting properties.

Subcritical Water Extraction of Phenolic Compounds from Vaccinium Dunalianum Wight Leaves and Their Antioxidant and Tyrosinase Inhibitory Activities in Vitro

Subcritical water extraction was used to extract bioactive phenolic compounds from Vaccinium dunalianum Wight leaves. The optimal extraction conditions were determined as an extraction temperature of 150 °C, an extraction time of 40 min, and a liquid-solid ratio of 35 : 1 mL/g. The total phenolic content reached 21.35 mg gallic acid /g, which was 16 % higher than that by hot water extraction. The subcritical water extraction extract exhibited strong scavenging activity of DPPH free radical and ABTS+ free radical, as well as significant tyrosinase inhibitory activity. The study suggests that subcritical water extraction can alter the composition of the extracts, leading to the production of various phenolic compounds, effective antioxidants, and tyrosinase inhibitors from Vaccinium dulciana Wight leaves. These findings confirm the potential of Vaccinium dunalianum Wight as a natural antioxidant molecule source for the medicine and food industries, and for the therapy of skin pigmentation disorders.

Synthesis, Molecular Docking and Tyrosinase Inhibitory Activity of the Decorated Methoxy Sulfonamide Chalcones: in vitro Inhibitory Effects and the Possible Binding Mode

In this study, a series of sulfonamide chalcones derivatives was synthesized and its chemical structures were confirmed by spectral characteristics. The synthesized compounds were evaluated for their tyrosinase inhibitory activities along with molecular docking study. The tyrosinase inhibitory results indicated that compounds 5b, 5c, 5f, 5g and 5h displayed the significant tyrosinase inhibitory activity and comparable to the standard drug (kojic acid). Compound 5c exhibits the most potent tyrosinase inhibition among the synthesized compounds with IC50 = 0.43±0.07 mM, L-DOPA as the substrate, and better than that of the standard kojic acid (IC50 = 0.60±0.20 mM). Molecular docking studies showed that the binding mode of some compounds is in the tyrosinase binding pocket surrounding the copper in the active site. The correlation between the docking results with IC50 values showed that the binding mode prediction of the test compounds would also be convincing. This comprehensive study allows for a possible mechanism for the antityrosinase activity of the sulfonamide chalcones. These sulfonamide chalcones bind to copper atoms of tyrosinase which responsible for the catalytic activity of tyrosinase. These compounds may be used as a lead for rational drug designing for the multi-functional tyrosinase inhibitor.

Insight into the phytochemical composition, biological activities and docking studies of Moringa oleifera Lam. to authenticate its use in biopharmaceutical industries

Moringa oleifera Lam. is a fast-growing deciduous tree native to the subcontinent with a wide array of uses. It is used as food plant by human and animals. Since it contains beneficial higher calcium, vitamin A, vitamin C, protein, potassium and iron contents, it is also used to treat malnutrition in children. The present study is conducted for comprehensive phytochemical profiling via total bioactive contents and ultra-high performance liquid chromatography (UHPLC-MS) analyses, and biological profiling by determining the antioxidant potential via DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid), FRAP (ferric reducing antioxidant power), CUPRAC (cupric reducing antioxidant power), phosphomolybdenum and metal chelation assays. In addition, α-amylase, α-glucosidase, acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and tyrosinase inhibition assays were also performed. Multivariate statistical analysis was used to investigate the relationship between biological activities and total bioactive content of the extracts. Chemical profiling showed that total phenolic contents are present in highest concentrations in ethyl acetate extracts of the aerial parts and seed. Further total bioactive contents were correlated with their optimum anti-oxidant capacities for ABTS, FRAP and CUPRAC. Altogether 67 phytochemicals were identified from aerial parts of the plant and its seed with major classes as phenolics, flavonoids, sesquiterpenoids and alkaloids. The ethyl acetate extract of seed showed good inhibition of AChE (2.77 mg GALAE/g extract) and BChE (8.05 mg GALAE/g extract) followed by the inhibition potential of water extract as 8.34 mg GALAE/g extract. The ethyl acetate extract also showed most significant (61.93 mg-KAE/g) tyrosinase inhibitory activity. The hexane extract of seed showed good inhibition of α-glucosidase (6.32 mmol ACAE/g extract) and α-amylase (0.47 mmol ACAE/g extract). In silico docking studies were performed, where two herbimycin and prekinamycin showed good binding affinity with all the enzymes. It can be concluded that the presence of complex phytochemicals with multi-functional potential distinguishes Moringa oleifera Lam. as a promising source of health-promoting component and recommended its use in biopharmaceutical industries.

Bioactive Compounds Isolated from Defatted Microalgal Biomasses of Botryococcus Braunii and Dunaliella Tertiolecta showing a Tyrosinase Inhibitory Activity

Aims: This study aims to elucidate the structural difference and biochemical properties of bioactive compounds of microalgal biomasses. Background : The structural difference and biochemical properties of bioactive compounds termed as water-soluble macromolecules (WSMs) are interested in evaluating their biological activities. Methods: This study was performed to elucidate the structural difference and biochemical properties of bioactive compounds termed as water-soluble macromolecules (WSMs) isolated from defatted microalgal biomasses of Botryococcus braunii and Dunaliella tertiolecta. Results: The compositional analysis of both WSMs revealed that WSM-Bb is a hetero-macromolecule consisting of various monosaccharides, whereas WSM-Dt was characterized as a homo-macromolecule that mainly consists of glucose. Interestingly, WSM-Bb showed the significant tyrosinase inhibitory activity with the increase of both the concentration and reaction time. Whereas, there was no significant inhibitory activity observed by WSM-Dt. Conclusion: Inhibitory action of WSM-Bb toward both tyrosinase and tyrosine in the either simultaneous or separate reaction may be mainly due to the physical affinity of WSM-Bb. These results emphasize the identification of the primary components of these WSMs and their relevance with the antioxidant function.

Isolation of Three New Diterpenes from Dodonaea viscosa.

An investigation into the methanol extracts obtained from the stems of Dodonaea viscosa led to the isolation of one nor-clerodane diterpene (1) and two labdane diterpenes (2, 3), as well as 17 known compounds (4-20). The structures of these compounds were elucidated based on chemical and spectral evidence. The stereochemical structure of the nor-clerodane diterpene was confirmed via its circular dichroism spectrum and calculated electronic circular dichroism spectrum. Isolated compounds were evaluated for their inhibitory effects on collagenase and tyrosinase. Since 5,7,4'-trihydroxy-3'-(4-hydroxy-3-methylbutyl)-5'-(3-methylbut-2-enyl)-3,6-dimethoxyflavone (9) showed collagenase inhibitory activity and scopoletin (12) had significant tyrosinase inhibitory activity, they were considered to be good candidates for cosmetic agents.

Ferulic Acid, A Component of Angelica Tenuissima Root Extract Induces Anti‐Melanogenic and Anti‐Oxidative Effects

Angelica tenuissima Nakai (Umbelliferae) has been used as a traditional medicine in Asia. The present study investigated the anti‐oxidative and anti‐melanogenic effects of ferulic acid (FA) derived from A. tenuissima root extract (ATE). Anti‐melanogenic activity was determined by intracellular melanin content and tyrosinase activity in α‐MSH (melanin stimulating hormone)‐stimulated B16F10 cells. The anti‐oxidative property of FA was measured using the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) scavenging free radical activity assays. FA significantly suppressed the production of melanin and the tyrosinase activity in α‐MSH‐induced cells. FA also showed the significant tyrosinase inhibitory activity and the DPPH/ABTS radical scavenging activities under cell‐free conditions. These results suggest that FA is responsible for the whitening effect of ATE and could be used as an ingredient in cosmeceutical skincare products.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

From mycelium to spores: A whole circle of biological potency of mosaic puffball

Methanol extracts of mosaic puffball (Handkea utriformis, Bovistella utriformis, Lycoperdon utriforme, Calvatia utriformis – current name is a subject of debate), from three different stages – mycelium (HUMIC), immature (HUI) and mature fruiting bodies (HUM) were characterized and tested for antioxidant, antimicrobial and inhibitory activity on tyrosinase, acetyholinesterase (AChE), butyrylcholinesterase (BuChE) and 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMG-CoA-R). Immature, edible, fruiting bodies were shown to be a good source of antioxidants (11.5 mg/g of extract) and cholesterol-lowering agent, lovastatin (234 μg/g of extract), and exhibited significant antimicrobial activity. In addition, HUI showed good and selective AChE (4.48 mg/mL) and non-lovastatin related HMG-CoA-R inhibition (1.16 mg/mL), which all together suggests that regular consumption of it may have health benefits. Mature fruiting bodies, inedible due to powdery consistence, have been used in traditional medicine for wound treatment; their extract was relatively rich in free ergosterol (31.65 mg/g of extract), N-acetylglucosamine (24 mg/g of extract), α-tocopherol (4 mg/g of extract) and had best overall antioxidant activity, which was in correlation with its highest phenolic content (19.4 mg GAE/mL). It also exhibited significant tyrosinase inhibitory activity (0.22 mg/mL) and thus could be used in medicinal and cosmetic products for wound healing and bleaching. Mycelium, which can be easily grown in laboratory conditions did not have the same properties as, neither immature or mature fruiting bodies, although it showed prominent antimicrobial activity, notably against Pseudomonas aeruginosa (MIC = 0.0625 mg/mL) and could be a source of antimicrobial compounds.

STUDY OF TYROSINASE INHIBITORY ACTIVITY AND PHYTOCHEMICAL SCREENING OF CASSIA FISTULA L. LEAVES

Objective: This study was carried out to evaluate the phytochemical constituents and tyrosinase inhibitory activity of Cassia fistula leaves.Methods: A tyrosinase inhibitory activity assay was performed by measuring the decrease in the intensity of color suggestive of the inhibition ofdopachrome formation resulting from the L-DOPA-tyrosinase reaction.Results: The test results showed that the tyrosinase inhibitory activity of the water fraction of C. fistula leaf extract had the highest IC50 value(152.031 μg/mL) among other fractions (n-hexane, ethyl acetate, and n-butanol). An enzyme kinetic assay showed that the water fraction of C. fistulaleaf extract inhibited tyrosinase with mixed-type inhibition. Phytochemical screening showed that the water fraction of C. fistula leaf extract containedalkaloids, flavonoids, glycosides, phenols, and tannins.Conclusion: The current study indicated that C. fistula leaves possess significant tyrosinase inhibitory activity.

Novel 1,3-oxazine-tetrazole hybrids as mushroom tyrosinase inhibitors and free radical scavengers: Synthesis, kinetic mechanism, and molecular docking studies.

A variety of 5-(2H-tetrazol-5-yl)-4-thioxo-2-(substituted phenyl)-4,5-dihydro-1,3-oxazin-6-ones (3a-k) have been synthesized from 1,3-oxazine-5-carbonitriles (2a-k). The protocol represents an efficient, facile, and novel route from easily available precursors to unprecedented structures that share 1,3-oxazine and tetrazole motifs of utmost value. All the synthesized compounds (3a-k) were evaluated for their inhibitory potential against mushroom tyrosinase. Results revealed that all examined 1,3-oxazine-tetrazole hybrids exhibited significant tyrosinase inhibitory activity while compound 3d having 2-bromophenyl moiety was the most potent among the series with IC50 value 0.0371±0.0018μM as compared to the reference kojic acid (IC50 =16.832±0.73μM). Inhibitory kinetics showed that compound 3d behaves as a competitive inhibitor. The molecular docking analysis was performed against target protein to investigate the binding mode. Moreover, compounds 3j and 3k displayed superior DPPH radical scavenging activity than other analogues.

Artopithecins A-D, Prenylated 2-Arylbenzofurans from the Twigs of Artocarpus pithecogallus and Their Tyrosinase Inhibitory Activities.

Four new prenylated 2-arylbenzofurans, namely artopithecins A-D (1-4), together with five known compounds (5-9) were isolated from the twigs of Artocarpus pithecogallus for the first time. Their structures were elucidated based on extensive spectroscopic analysis and in comparison with literature data. All isolates were evaluated for their inhibitory activities against mushroom tyrosinase. Compounds 3 and 4 displayed significant tyrosinase inhibitory activities with IC50 values of 37.09±0.33 and 38.14±0.21 µM, respectively.

Biochemical and phylogenetic analysis of Eugenia and Syzygium species from Mauritius

The Myrtaceae represents a plant family with several species having important medicinal virtues. In view of these properties four Syzygium species namely S. latifolium, S. commersonii, S. coriaceum, S. petrinense and two Eugenia species namely E. pollicina and E. pyxidata were studied. Phytochemical analysis showed that the methanol extracts had higher content of total phenolics and total flavonoids than the hexane extracts. The in vitro antioxidant activity evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Ferric reducing antioxidant potential (FRAP) assays was significant. The antibacterial activity of the extracts against Staphylococcus epidermidis, Staphylococcus aureus, Propionibacterium acnes and Escherichia coli was also promising. Species studied displayed significant tyrosinase inhibitory activity with S. petrinense having the highest activity. Interestingly, when the expression analysis of the tyrosinase cDNA in mouse melanocyte cells was studied it was observed that the methanolic Syzygium extracts inhibited melanogenesis by upregulating or downregulating the tyrosinase gene. Phylogenetic analysis of the ribosomal DNA sequences showed the genetic uniqueness of each plant species reflecting in their unique biological activity. Bioprospecting of endemic Mauritian Eugenia and Syzygium could be envisaged against acne vulgaris, skin hyperpigmentation and possible exploitation as phytotherapeutics.

Isolation, Identification, and Quantification of Tyrosinase and α-Glucosidase Inhibitors from UVC-Irradiated Mulberry (Morus alba L.) Leaves.

Methanol extracts from ultraviolet (UV) C-irradiated mulberry leaves (UVC-IML) exhibit stronger tyrosinase and α-glucosidase inhibitory activities than those from unirradiated mulberry leaves. Through a bioassay-guided fractionation and purification process, two oxyresveratrol derivatives, oxyresveratrol (ORT) and 4′-prenyloxyresveratrol (PORT), and six 2-arylbenzofuran derivatives [moracin B (MCB), moracin C (MCC), moracin M (MCM), moracin N (MCN), 6,5′-dimethoxymoracin M (DMMCM), and chalcomoracin (CMC)] were isolated from the methanol extract from UVC-IML. Their chemical structures were determined by UV, mass, and nuclear magnetic resonance spectrometry. ORT and PORT showed potent tyrosinase inhibitory activities with the half maximal inhibitory concentration (IC50) values of 0.57 and 0.90 μM, respectively, and CMC exhibited significant tyrosinase and α-glucosidase inhibitory activity with IC50 values of 5.61 and 6.00 μM, respectively. Levels of these eight compounds were increased significantly following irradiation compared with untreated mulberry leaves; ORTs increased approximately 4 fold and moracins increased 2~16 fold. These data suggest that UVC-IML may represent a promising source of nutraceuticals and cosmeceuticals for prevention of diabetes and skin aging.

Antibacterial, antioxidant and cytotoxic activities of triterpenes and flavonoids from the aerial parts of Salvia barrelieri Etl.

From the aerial parts of Salvia barrelieri Etl. (Lamiaceae), 12 compounds including a new triterpene, 3β-acetoxy-olean-18-ene-2α-ol, were isolated. Their structures were established by the combination analyses of spectroscopy including 1D-, 2D-NMR and HRESIMS and in comparison with the reported data in the literature. The antibacterial activity of these compounds was evaluated by bioautography on Staphylococcus aureus followed by the determination of MIC values by serial dilution technique against five bacteria. Three compounds were active against Enterococcus faecalis, S. aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa (MIC 15.1 to 125 μg/mL). Two compounds showed moderate DPPH radical scavenging activity (IC50 79.1 and 21.2 μg/mL). These compounds did not show significant tyrosinase inhibitory activities (IC50> 1.5 mg/mL). Their cytotoxic activity was evaluated against promyelocytic leukaemia (HL60), human erythromyeloblastoid leukaemia (K562) and fibrosarcoma (HT1080) cell lines and four compounds exhibited a moderate cytotoxic activity (IC50 28.75 to 85.0 μM).

Chemical constituents of Piper aduncum and their inhibitory effects on soluble epoxide hydrolase and tyrosinase

A new compound, 2(S)-isobutanol 2-O-β-d-arabinopyranosyl(1→6)-O-β-d-glucopyranoside (1), along with ten known compounds (2–11) were isolated from Piper aduncum L. leaves. The effects of these compounds on soluble epoxide hydrolase and tyrosinase inhibition were evaluated. Among them, compounds 3, 8, and 9 exhibited significant tyrosinase inhibitory activity with IC50 values of 39.3 ± 1.8, 41.3 ± 2.2, and 37.5 ± 2.7 µM, respectively. However, the effects of isolated compounds on soluble epoxide hydrolase inhibition were weak or absent, and compounds 4 and 11 showed the highest inhibitory activity with values of 61.2 ± 4.3 and 60.6 ± 3.7 % at a concentration of 100 μM.