Relationships between degree of polymerization and activities: A study on condensed tannins from the bark of Ficus altissima.

Condensed tannins were isolated from the bark of Ficus altissima and fractionated into four subcomponents on a Sephadex LH-20 column with 60 %, 80 %, 100 % methanol, and 70 % acetone, separately. Their structures were characterized by MALDI-TOF MS coupled with HPLC-ESI-MS and confirmed to be polymers of B-type procyanidin glucosides, procyanidins, and prodelphinidin glucosides. The degree of polymerization (DP) of these polymers was as high as 21, and the mDPs of the four subcomponents were calculated as 2.4, 6.6, 10.5 and 13.4, respectively. They competitively or noncompetitively suppressed the activities of tyrosinase and α-glucosidase through hydrogen bonding and hydrophobic interaction. And they also showed a powerful antioxidative activity. Correlation analyses verified that the anti-tyrosinase capacity exhibited a significant positive correlation (R2monophenolase = 0.9167 and R2diphenolase = 0.9302) with mDP within the methanol-water system, and the anti-α-glucosidase activity also showed a significant positive correlation with the mDP (R2 = 0.9187). In contrast, the antioxidant capability showed a significant negative correlation with the mDP (R2DPPH = 0.9258, R2ABTS = 0.9372). This study confirmed that condensed tannins from the bark of F. altissima were desirable anti-tyrosinase, anti-α-glucosidase, and antioxidant agents, and elucidated the relationships of their mDP (molecular weight) and activities, which provided a scientific basis for the comprehensive utilization of these polymers in the food, cosmetics, medicine and other fields.

Shoot Cultures of Vitis vinifera (Vine Grape) Different Cultivars as a Promising Innovative Cosmetic Raw Material-Phytochemical Profiling, Antioxidant Potential, and Whitening Activity.

The primary purpose of this work was the initiation and optimization of shoot cultures of different Vitis vinifera L. cultivars: cv. Chardonnay, cv. Hibernal, cv. Riesling, cv. Johanniter, cv. Solaris, cv. Cabernet Cortis, and cv. Regent. Cultures were maintained on 30-day growth cycles using two media, Murashige and Skoog (MS) and Schenk and Hildebrandt (SH), with various concentrations of plant growth regulators. Tested media ('W1'-'W4') contained varying concentrations of 6-benzylaminopurine (BA) in addition to indole-3-butyric acid (IBA) and 1-naphthaleneacetic acid (NAA). High performance liquid chromatography coupled with mass spectrometry (UPLC-MS) was used for metabolomic profiling. In all tested extracts, 45 compounds were identified (6 amino acids, 4 phenolic acids, 13 flavan-3-ols, 3 flavonols, and 19 stilbenoids). Principal component analysis (PCA) was performed to assess the influence of the genotype and medium on metabolic content. PCA showed that metabolic content was mainly influenced by genotype and to a lesser extent by medium composition. MS media variants induced the amino acid, procyanidin, and flavan-3-ol production. In addition, the antioxidant potential and anti-tyrosinase activity was measured spectrophotometrically. The studies on antioxidant activity clearly reveal very high efficiency in reducing free radicals in the tested extracts. The strongest tyrosinase inhibition capacity was proved for shoots cv. Hibernal cultured in SH medium and supplemented with NAA, with an inhibition of 17.50%. These studies show that in vitro cultures of V. vinifera cvs. can be proposed as an alternative source of plant material that can be potentially used in cosmetic industry.

Variation in Yield, Chemical Composition and Biological Activities of Essential Oil of Three Curcuma Species: A Comparative Evaluation of Hydrodistillation and Solvent-Free Microwave Extraction Methods.

The essential oils of three medicinally important Curcuma species (Curcuma alismatifolia, Curcuma aromatica and Curcuma xanthorrhiza) were extracted using conventional hydro-distillation (HD) and solvent free microwave extraction (SFME) methods. The volatile compounds from the rhizome essential oils were subsequently analysed by GC-MS. The isolation of essential oils of each species was carried out following the six principles of green extraction and comparison was made between their chemical composition, antioxidant, anti-tyrosinase and anticancer activities. SFME was found to be more efficient than HD in terms of energy savings, extraction time, oil yield, water consumption and waste production. Though the major compounds of essential oils of both the species were qualitatively similar, there was a significant difference in terms of quantity. The essential oils extracted through HD and SFME methods were dominated by hydrocarbon and oxygenated compounds, respectively. The essential oils of all Curcuma species exhibited strong antioxidant activity, where SFME was significantly better than HD with lower IC50 values. The anti-tyrosinase and anticancer properties of SFME-extracted oils were relatively better than that of HD. Further, among the three Curcuma species, C. alismatifolia essential oil showed the highest rates of inhibition in DPPH and ABTS assay, significantly reduced the tyrosinase activity and exhibited significant selective cytotoxicity against MCF7 and PC3 cells. The current results suggested that the SFME method, being advanced, green and fast, could be a better alternative for production of essential oils with better antioxidant, anti-tyrosinase and anticancer activities for application in food, health and cosmetic industries.

Preparation, antioxidant and tyrosinase inhibitory activities of chitosan oligosaccharide-hydroxypyridinone conjugates.

Two novel chitosan oligosaccharide (COS)-hydroxypyridone (HPO) conjugates were prepared by reacting chitosan oligosaccharide with 2-chloromethyl-5-hydroxypyridone (HPO), which was synthesized by a series of reactions starting from kojic acid. The degree of substitution of COS-HPO2 reached 1.2, with a yield of 74.9%. The structure of the two conjugates (COS-HPO1 and COS-HPO2) was identified by NMR and FT-IR analysis. The two conjugates showed significantly higher free radical (DPPH•, ABTS+• and •OH) scavenging activity and reducing power than those of COS and HPO (p < 0.05). Both COS-HPO1 and COS-HPO2 possessed significantly stronger tyrosinase inhibitory activity than those of COS, with IC50 values of 0.67 and 0.28 mg/mL for monophenolase, 0.73 and 0.30 mg/mL for diphenolase, respectively. In addition, the conjugates were found to be non-toxic to RAW264.7 macrophages and MRC-5 human lung cells. This work proposes a facile method to enhance the oxidative and tyrosinase inhibitory properties of COS.

Phytochemical compositions and biological activities of the branches and leaves of Ormosia hosiei Hemsl. et Wils.

Ormosia hosiei Hemsl. et Wils. is an economical and medicinal plant, increasingly cultivated in China; however, its branches and leaves are often pruned as waste. This is the first study focused on the phytochemical profiles and antioxidant, anti-α-glucosidase, anti-tyrosinase, and anti-neuroinflammatory activities of the branches and leaves of O. hosiei. Herein, thirty-seven characteristic compounds were identified by UPLC-MS/MS and twelve were detected for the first time in O. hosiei. Twenty-seven phenolics were further quantified and significant differences in phenolic compositions between the branches and leaves of O. hosiei were observed. The ethanol extracts exhibited promising antioxidant, anti-α-glucosidase, anti-tyrosinase, and anti-neuroinflammatory effects, and the bioactivities significantly correlated with total phenolic content and twelve individual phenolics. Naringin, genistein, vitexin, vitexin-2-O-rhamnoside, syringaresinol and syringaresinol-4-O-ß-D-glucopyranoside can be considered potential quality markers of O. hosiei. Our results provided solid evidence that the branches and leaves of O. hosiei deserve more attention and exploitation, considering the potential to be developed as functional foods or herbal medicines.

Mushroom ß-Glucan Recovered from Antler-Type Fruiting Body of Ganoderma lucidum by Enzymatic Process and Its Potential Biological Activities for Cosmeceutical Applications.

Mushrooms are incredibly valuable macro fungi that are an important and integral part of the ecosystem. In addition to being used as cuisine, mushrooms have been used for medicinal purposes for many centuries. This research applied a process for recovering ß-glucan (BG) from the antler-type fruiting body of Ganoderma lucidum as well as tested the biological activities related to cosmeceutical applications. The characterization of complex structure was performed by fourier-transform infrared (FTIR) and nuclear magnetic resonance (MNR) spectroscopies. The obtained extract contained 40.57% BG and 7.47% protein, with the detectable bioactivities of anti-tyrosinase and antioxidation. Consequently, it showed the activity that can be used to whiten the skin by reducing or inhibiting the process of skin pigmentation. The BG also showed moderate activities of anti-collagenase, anti-elastase, and anti-hyaluronidase. The test by the HET-CAM confirmed no skin irritation of the complex extract. Based on human peripheral blood mononuclear cell (PBMC) test, the BG had no significant inhibiting effect on cell viability. In addition, the obtained BG had functional properties higher than commercially available BG, especially oil-binding capacity. These findings provided new insights into the potential application of G. lucidum BG as a polymeric material in the cosmeceutical industries.

Looking for peptides from rice starch processing by-product: Bioreactor production, anti-tyrosinase and anti-inflammatory activity, and in silico putative taste assessment.

One of the major challenges for the modern society, is the development of a sustainable economy also aiming at the valorization of agro-industrial by-products in conjunction with at a significant reduction of generated residues from farm to retail. In this context, the present study demonstrates a biotechnological approach to yield bioactive peptides from a protein fraction obtained as a by-product of the rice starch production. Enzymatic hydrolysis, with the commercial proteases Alcalase and Protamex, were optimized in bioreactor up to 2 L of volume. The two best digestates, selected with respect to peptide release and extract antioxidant capacity, were further fractionated (cut-offs of 10, 5, and 1 kDa) via cross-flow filtration. Amino acid composition indicated that most of the fractions showed positive nutritional characteristics, but a putative bitter taste. A fraction obtained with Alcalase enzyme (retentate 8 kDa) exerted anti-inflammatory potential, while the smaller molecular weight fractions (retentate 1-5 kDa and permeate < 1 kDa) were more active in tyrosinase inhibition. The latter were further sub-fractionated by size-exclusion chromatography. From the 15 most anti-tyrosinase sub-fractions, 365 peptide sequences were identified via liquid chromatography coupled with high resolution mass spectrometry. The present data support the possible exploitation of bioactive peptide from rice starch by-product as ingredients into food, nutraceutical, pharmaceutical, and cosmetic formulations.

Undescribed alkyne-geranylcyclohexenetriols from the endophyte Diaporthe caulivora 09F0132 and their anti-melanogenic activity.

To explore valuable endophytic fungus from Formosan Lauraceous plants as natural medicinal products, the fungus, Diaporthe caulivora isolated from leaves of Neolitsea daibuensis, was investigated. Through a thorough investigation of the ethanolic extract of the solid fermentation of D. caulivora 09F0132, six undescribed alkyne-geranylcyclohexenetriols, caulivotrioloxins A-F, one undescribed trichopyrone, diapopyrone, two undescribed sesquiterpenes, caulibysins A-B, one compound firstly isolated from the natural source, 3-O-desmethyl phomentrioloxin, and eight known compounds have been successfully identified. The absolute configuration of caulibysin A was confirmed by single-crystal X-ray diffraction, and those of (3R,8S)-5,7-dihydroxy-3-(1-hydroxyethyl)phthalide and (3S,8S)-5,7-dihydroxy-3-(1-hydroxyethyl)phthalide were determined by circular dichroism (CD) spectra. Among the isolated compounds, caulivotrioloxin A concentration-dependently decreased the cellular melanin contents and tyrosinase activities in mouse melanoma B16-F10 cells, suggesting the anti-melanogenic potentials. The anti-melanogenic effects of caulivotrioloxin A involved the decrease in the protein expressions of melanogenic enzymes, including tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2. Taken together, these results suggested that the isolates from D. caulivora could be served as natural melanogenesis inhibitors for cosmeceutical applications.

Inhibitory activity of soybean (Glycine max L. Merr.) Cell Culture Extract on tyrosinase activity and melanin formation in alpha-melanocyte stimulating Hormone-Induced B16-F10 melanoma cells.

BACKGROUND: Hyperpigmentation, which causes excessive melanin synthesis and accumulation, is an important issue in the cosmetic industry. Since compounds developed against hyperpigmentation often come with side effects such as skin irritation and contact dermatitis, new studies focus on the use of natural agents that have no side effects. METHODS AND RESULTS: In this study, it was found that the effects of soybean cell culture extract (SCE) on alpha-melanocyte-stimulating hormone (α-MSH) induced melanogenesis in B16-F10 murine melanoma cells. The cells were incubated with SCE for 48 h after treatment with α­MSH for 24 h to analysis the melanin content, cellular tyrosinase activity, and gene and protein expression. SCE at 1 mg/mL decreased melanin content and tyrosinase activity by 34% and 24%, respectively, compared to the α-MSH-treated group, which did not decrease cell viability. In addition, SCE (1 mg/mL) downregulated the expression of tyrosinase (TYR), tyrosinase-related protein (TRP)-1, tyrosinase-related protein (TRP)-2, and microphthalmia-associated transcription factor (MITF) genes 1.5-, 1.5-, 2-, and 2-fold, respectively. Furthermore, SCE inhibited the expression of TYR, TRP1, and TRP2 by decreasing the expression of MITF, as shown in a western blot assay. CONCLUSIONS: This study suggests that SCE reveals dose-dependent inhibition of melanin synthesis through the suppression of tyrosinase activity as well as molecular levels of TYR, TRP1, TRP2, and MITF in B16-F10 murine melanoma cells. Therefore, SCE has the potential to be an effective and natural skin-whitening agent for application in the cosmetic industry.

Phytochemicals and anti-tyrosinase activities of Paeonia ostii leaves and roots.

Tree peony (sect. Moutan) is a kind of Traditional Chinese Medicine and ornamental plant, which has been widely cultivated and utilized for thousands of years. To further study the active components of Paeonia ostii (Moutan, Fengdan), six fractions (soluble free (F), soluble esterification, soluble glycosylation, insoluble bound, insoluble esterification and insoluble glycosylation) were extracted from the leaves and roots by alkaline and acid treatment for the first time. Twenty-one typical compounds were identified and quantified by HPLC-MS. The results showed that total phenolic content (TPC) in peony roots (PR) and peony leaves (PL) were as high as 125.48 and 280.38 mg GAE·g-1 dw, which maximizes the extraction efficiency of phenolic compounds, especially leaves, compared with the conventional method. PR-F and PL-F had the highest TPC, antioxidant and anti-tyrosinase activities. Paeoniflorin was the main compounds in PL and PR. It and pentagalloylglucose (PGG) almost reached the anti-tyrosinase level of kojic acid, but they showed different inhibitory mechanisms by molecular docking. On the whole, PR-F, PL-F, PGG and paeoniflorin might be potential for skin whitening products.

Comparison of Various Solvent Extracts and Major Bioactive Components from Portulaca oleracea for Antioxidant, Anti-Tyrosinase, and Anti-α-Glucosidase Activities.

Portulaca oleracea is a well-known species for traditional medicine and food homology in Taiwan. In traditional medicine, P. oleracea is also used to treat gastrointestinal disorders, liver inflammation, fever, severe inflammation, and headaches. We investigated antioxidant, anti-tyrosinase, and anti-α-glucosidase activities of various solvent extracts and major bioactive components from P. oleracea. Ethanol and acetone extracts showed potent DPPH, ABTS, and hydroxyl radical scavenging activities. Chloroform and n-hexane extracts displayed significant superoxide radical scavenging activity. Furthermore, ethyl acetate and acetone extracts of P. oleracea showed potent anti-tyrosinase and anti-α-glucosidase activities. Examined and compared to the various solvent extracts for their chemical compositions using HPLC analysis, we isolated seven major compounds and analyzed their antioxidant, anti-tyrosinase, and anti-α-glucosidase activities. Seven active compounds of P. oleracea, especially quercetin, rosmarinic acid, and kaempferol, exhibited obvious antioxidant, anti-tyrosinase, and anti-α-glucosidase activities. The molecular docking model and the hydrophilic interactive mode of tyrosinase and α-glucosidase revealed that active compounds might have a higher antagonistic effect than commonly inhibitors. Our result shows that the active solvent extracts and their components of P. oleracea have the potential as natural antioxidants, tyrosinase and α-glucosidase inhibitors. Our results suggest that the active solvent extracts of P. oleracea and their components have potential as natural antioxidants, tyrosinase and α-glucosidase inhibitors.

Tyrosinase Inhibitory and Antioxidant Activity of Enzymatic Protein Hydrolysate from Jellyfish (Lobonema smithii).

The optimization of antioxidant and anti-tyrosinase activity during jellyfish hydrolysate preparation was studied using a response surface methodology (RSM) with a face-centered composite design. The influence of the hydrolysis duration and the enzyme concentration on the IC50 of the DPPH and ABTS radical scavenging activity, ferric-reducing antioxidant power (FRAP), the degree of hydrolysis (DH), yield, and the IC50 value of tyrosinase inhibitory activity were determined. The optimum conditions for the production of jellyfish hydrolysate using alcalase (JFAH), flavourzyme (JFFH), or papain (JFPH) were achieved at hydrolysis times of 360, 345, or 360 min, respectively, and at an enzyme concentration of 5.0%. JFFH had the highest antioxidant and tyrosinase inhibitory activity. JFAH, JFFH, and JFPH concentrations of 2.5 mg/mL resulted in HaCaT cells (IC80) having a survival rate of 80%. The amino acid profile of JFFH contained about 43% hydrophobic and 57% hydrophilic amino acids, comprising Gly, Cys, Glx, Asx, which were dominant. The isolation of a peptide fraction from JFFH was carried out using ultrafiltration membranes (10, 3, and 1 kDa) and gel filtration chromatography. Fraction-III (1-3 kDa) showed the highest antioxidative and tyrosinase inhibitory activity.

New bioactive α-pyrone from wild mushroom Paxillus involutus.

Chemical investigation of Paxillus involutus (Batsch) Fr. led to the isolation of a pair of new enantiomers (E)-5-(4-methoxy-2-oxo-2H-pyran-6-yl)pent-4-en-1-yl 2-hydroxypropanoate (1a/1b) along with 14 known compounds (2-15) for the first time from this mushroom. The structures of new compounds were elucidated based on extensive spectroscopic data analysis of MS, 1D and 2D NMR, and their absolute configurations were confirmed by comparison of the experimental and calculated ECD data. Compounds 1a and 1b exhibited radical scavenging activities with IC50 values ranging from 10.39 ± 2.26 to 20.43 ± 3.74 µg/mL. Compounds 1a and 1b also showed moderate anti-tyrosinase activity with IC50 value of 25.66 ± 2.84 and 26.82 ± 3.19 µg/mL.

The Major Stilbene Compound Accumulated in the Roots of a Resistant Variety of Phoenix dactylifera L. Activates Proteasome for a Path in Anti-Aging Strategy.

The main objective of the present study is to estimate, through differential analysis, various biological activities of total phenolics content in alcoholic extracts of three date palm varieties sensitive or resistant to Fusarium oxysporum. sp Albidinis. Here, stilbene products with antioxidant and bioactive capacities were evidenced in resistant variety Taabdount (TAAR). Furthermore, the methanolic fraction of the TAAR-resistant date palm variety contains a significant product, determined by LC-MS/MS and 1H, 13C NMR, belonging to the family of hydroxystilbenes, which exhibits antioxidant capacities, inhibits the mushroom tyrosinase activity, and activates and exerts a protective effect on hypochlorite-induced damage in 20S proteasome of human dermal fibroblast aged cells. Altogether, the present results indicate that hydroxystilbene present in resistant Phoenix dactylifera L. should be studied to understand the way that the stilbene could exert anti-aging ability.

Benzylidene-6-hydroxy-3,4-dihydronaphthalenone chalconoids as potent tyrosinase inhibitors.

BACKGROUND AND PURPOSE: Tyrosinase enzyme has a key role in melanin biosynthesis by converting tyrosine into dopaquinone. It also participates in the enzymatic browning of vegetables by polyphenol oxidation. Therefore, tyrosinase inhibitors are useful in the fields of medicine, cosmetics, and agriculture. Many tyrosinase inhibitors having drawbacks have been reported to date; so, finding new inhibitors is a great need. EXPERIMENTAL APPROACH: A variety of 6-hydroxy-3,4-dihydronaphthalenone chalcone-like analogs (C1-C10) have been synthesized by aldol condensation of 6-hydroxy tetralone and differently substituted benzaldehydes. The compounds were evaluated for their inhibitory effect on mushroom tyrosinase by a spectrophotometric method. Moreover, the inhibition manner of the most active compound was determined by Lineweaver-Burk plots. Docking study was done using AutoDock 4.2. The drug-likeness scores and ADME features of the active derivatives were also predicted. RESULTS/FINDINGS: Most of the compounds showed remarkable inhibitory activity against the tyrosinase enzyme. 6-Hydroxy-2-(3,4,5-trimethoxybenzylidene)-3,4-dihydronaphthalen-1(2H)-one (C2) was the most potent derivative amongst the series with an IC50 value of 8.8 µM which was slightly more favorable to that of the reference kojic acid (IC50 = 9.7 µM). Inhibitory kinetic studies revealed that C2 behaves as a competitive inhibitor. According to the docking results, compound C2 formed the most stable enzyme-inhibitor complex, mainly via establishing interactions with the two copper ions in the active site. In silico drug-likeness and pharmacokinetics predictions for the proposed tyrosinase inhibitors revealed that most of the compounds including C2 have proper drug-likeness scores and pharmacokinetic properties. CONCLUSION AND IMPLICATIONS: Therefore, C2 could be suggested as a promising tyrosinase inhibitor that might be a good lead compound in medicine, cosmetics, and the food industry, and further drug development of this compound might be of great interest.

Snail mucus from the mantle and foot of two land snails, Lissachatina fulica and Hemiplecta distincta, exhibits different protein profile and biological activity.

OBJECTIVE: Snails secrete different types of mucus that serve several functions, and are increasingly being exploited for medical and cosmetic applications. In this study, we explored the protein pattern and compared the biological properties of the mucus secreted from the mantle collar and foot of two snail species, Lissachatina fulica and Hemiplecta distincta. RESULT: Protein profile showed a different pattern between the two species and between the two secretory parts. The mantle-specific protein bands were further characterized and among them was an antibacterial protein, achacin. Accordingly, the mucus from the mantle exhibited the higher antibacterial activity than that from the foot in both snail species. The mucus from H. distincta, first reported here, also showed antibacterial properties, but with a lower activity compared to that for L. fulica. Snail mucus also exhibited anti-tyrosinase activity and antioxidant activity but with no significant difference between the foot and mantle mucus. These results indicate some different protein compositions and biological activities of snail slime from the mantle and foot, which might be associated with their specific functions in the animal and are useful for medical applications.

Dopamine-Mediated Vanillin Multicomponent Derivative Synthesis via Grindstone Method: Application of Antioxidant, Anti-Tyrosinase, and Cytotoxic Activities.

PURPOSE: This study aimed to determine the extent of contribution of dopamine to antioxidant and anti-tyrosinase activities, by dopamine addition to vanillin. This study achieved the synthesis of dopamine-associated vanillin Mannich base derivatives prepared via a one-step reaction involving a green chemistry approach, and investigation of antioxidant and anti-tyrosinase activities. METHODS: Novel one-pot synthesis of Mannich base dopamine-connected vanillin (1a-l) derivatives can be achieved via green chemistry without using a catalyst. Newly-prepared compounds were characterised with FTIR and NMR (1H and 13C) spectra, mass spectra, and elemental analyses. In total, 12 compounds (1a-l) were synthesised and their antioxidant and anti-tyrosinase activities evaluated. Antioxidant activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO), hydrogen peroxide (H2O2), and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and diammonium assays, ABTS•+ radical scavenging, and linoleic acid peroxidation were used to screen all synthesised compounds (1a-l) for anti-tyrosinase activities and cytotoxicity against MCF-7 and Vero cell lines;. RESULTS: The compound 1k inhibited (IC50:11.02µg/mL) the DPPH-scavenging activity to a greater extent than the standard BHT (IC50:25.17µg/mL), and showed high activity in H2O2 and NO scavenging assays. Compound 1e was more potent (96.21%) against ABTS and compound 1k was more potent (95.28%) against 2,2'-azobis(2-amidinopropane)dihydrochloride antioxidant than the standard trolox. All synthesised compounds were screened for anti-tyrosinase inhibitory activity. Compound 1e had higher activity against tyrosinase (IC50=10.63 µg/mL), than kojic acid (IC50=21.52µg/mL), and was more cytotoxic (GI50 0.01µM) against MCF-7 cell line than the doxorubicin standard and other tested compounds. CONCLUSION: In this study, all compounds were found to possess significant antioxidant and anti-tyrosinase activities. Compounds 1e and 1k performed well, compared with other compounds, in all assays. In addition, this study successfully identified several promising molecules that exhibited antioxidant and anti-tyrosinase activities.

Isolation and structure elucidation of anti-tyrosinase compounds from the seeds of Crotalaria pallida.

Three new compounds, crotalariapallins A-C (1-3), were isolated from the 95% EtOH extract of the seeds of Crotalaria pallida. Their structures were established based on extensive spectroscopic methods, including HRESIMS, UV, 1D and 2D NMR. All compounds were evaluated for their inhibitory activities to tyrosinase. These compounds showed different degrees of inhibitory activities, among them, compound 3 exhibited the strongest inhibition activity (IC50 = 0.42 mM).

NMR metabolic profiling of Greek propolis samples: Comparative evaluation of their phytochemical compositions and investigation of their anti-ageing and antioxidant properties.

The present study aimed to investigate the metabolic profile, as well as the antioxidant and anti-ageing activities of twenty propolis samples from different regions of Greece. Chemical profiling of methanolic extracts was investigated using HPTLC and 1H-NMR techniques. Their antioxidant activity was evaluated by free radical scavenging methods (DPPH and ABTS), whereas anti-ageing properties were assessed as anti-collagenase activity. Extracts were also investigated in vitro for their ability to inhibit tyrosinase, which is responsible for the oxidation of L-DOPA to dopachrome and the production of melanin. The HPTLC and NMR analysis revealed high variability in the phytochemical profile of the methanolic extracts, with three major groups to be observed: a) Group I, consisting of samples rich in terpenoids, which present low antioxidant but high anti-tyrosinase activity, b) Group II, consisting of samples rich in flavonoids, which form a broad cluster with major similarities at the aromatic region and showed the highest anti-oxidant and anti-collagenase activities and c) Group III, consisting of samples with lower flavonoid content than the samples of Group II, which exhibited moderate antioxidant, anti-collagenase and anti-tyrosinase activities. In conclusion, this study has shown high differentiation on the chromatographic and spectroscopic metabolic profile of Greek propolis samples of different geographical origin, which is also reflected in their biological properties. Their important effects as antioxidant, anti-tyrosinase and anti-collagenase agents make propolis an important potent ingredient in the industry of food supplements and cosmeceuticals. Moreover, a correlation of a particular chemical propolis type to a specific type of biological activity will allow to prepare standardized extracts and develop food supplements and cosmeceuticals possessing the desired pharmacological properties.

Identification of a Proanthocyanidin from Litchi Chinensis Sonn. Root with Anti-Tyrosinase and Antioxidant Activity.

This work follows an ethnobotanical study that took place in the island of Mayotte (France), which pointed out the potential properties of Litchi chinensis Sonn. roots when used to enhance skin health and appearance. Through in vitro testing of a crude methanolic extract, high anti-tyrosinase (skin whitening effect) and antioxidant activities (skin soothing effect) could be measured. HPLC successive bio-guided fractionation steps allowed the purification of one of the compounds responsible for the biological activities. The isolated compound was characterized by UV, IR, MS and 2D-NMR, revealing, for the first time in Litchi chinensis Sonn. roots, an A-type proanthocyanidin and thus revealing a consensus among the traditional use shown by the ethnobotanical study, in vitro biological activities and chemical characterization.