Antioxidant activity, anti-tyrosinase activity, molecular docking studies, and molecular dynamic simulation of active compounds found in nipa palm vinegar.

Tyrosinase is a key enzyme in melanogenesis and its inhibitors have become increasingly because of their potential activity as hypopigmenting agents which have less side effects. Nipa palm vinegar is an aqueous product that is normally used as a food supplement. The aim of this study was to study the determination of antioxidant activity and tyrosinase inhibitory activities of aqueous extract of original nipa palm vinegar (AE O-NPV), nipa palm vinegar powder (NPV-P) and aqueous extract of nipa palm vinegar powder (AE NPV-P) were examined. Nipa palm vinegars were evaluated the phenolic and flavonoid content, and the active compounds which were submitted to molecular docking and molecular dynamic simulation, chemoinformatics, rule of five, skin absorption and toxicity. The highest phenolic and flavonoid contents in the AE O-NPV were 2.36 ± 0.23 mg gallic acid equivalents/g extract and 5.11 ± 0.59 mg quercetin equivalents/g, and the highest ABTS radical cation scavenging activity was also found. The AE O-NPV, NPV-P and AE NPV-P showed anti-mushroom tyrosinase activity. The HPLC analysis showed that there were vanillic acid and three flavonoids (catechin, rutin and quercetin). The molecular docking study revealed that the binding of the vanillic acid and three flavonoids occurred in the active site residues (histidine and other amino acids). Moreover, the number of hydrogen bond acceptors/donors, solubility, polar surface area and bioavailability score of the vanillic acid and three flavonoids were acceptable compared to Lipinski's Rule of Five. The molecular dynamic simulation showed that vanillic acid interacts with HIS284 through π-π stacking hydrophobic interactions and forms a metal-acceptor interaction with the copper molecule at the tyrosinase active site. All compounds revealed good skin permeability and nontoxicity. Nipa palm vinegar could be a promising source of a new ingredient for tyrosinase inhibition for cosmetics or pharmaceutical products.

Melanogenesis Inhibitory Activity, Chemical Components and Molecular Docking Studies of Prunus cerasoides Buch.-Ham. D. Don. Flowers.

Safe depigmenting agents are currently increasing in the cosmetic or pharmaceutical industry because various compounds have been found to have undesirable side effects. Therefore, the present study aimed to investigate the melanogenesis inhibitory effects of Prunus cerasoides Buch. -Ham. D. Don. flower extracts and their molecular mechanism in B16F10 mouse melanoma cells. Moreover, we also examined phenolic and flavonoid contents, antioxidant activity, chemical constituents of potential extracts, and molecular docking. The highest phenolic and flavonoid contents with the greatest scavenging activity were found in the butanol extract of the P. cerasoides flower compared to other extracts. From all extracts, only crude, diethyl ether, and butanol extracts showed an inhibition of mushroom tyrosinase activity, cellular tyrosinase activity, and melanin content as well as the downregulation of the gene expression of the microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 (TRP-1), and tyrosinase-related protein-2 (TRP-2) in α-MSH-stimulated B16F10 cells. Based on the molecular docking study, n-hexadecanoic acid, heptadecanoic acid, octadecanoic acid, 9,12-octadecadienoic acid, 9,12,15-octadecanoic acid, and eicosanoic acid might show an inhibitory effect against tyrosinase and MITF. In conclusion, this finding demonstrates that both the diethyl ether and butanol extracts of the P. cerasoides flower can effectively reduce tyrosinase activity and melanin synthesis through the downregulation of the melanogenic gene expression in B16F10 cells and through the molecular docking study. Taken together, the diethyl ether and butanol extracts of the P. cerasoides flower could be an anti-melanogenic ingredient for hyperpigmentary or melasma treatment.

Artemisia lactiflora Extracts Prevent Inflammatory Responses of Human Macrophages Stimulated with Charcoal Pyrolysis Smoke.

Artemisia lactiflora, a Chinese-origin plant, has been reported to have unique phytochemicals responsible for its medicinal properties. The growth of the agricultural industry emits air pollution, which has adverse effects on health. There are limited scientific reports on the biological activities of A. lactiflora. Studies on its activities and mechanisms may provide insight into its use in medicinal purposes to treat those health problems and conditions. In this study, leaves of A. lactiflora were extracted and fractioned with solvents of different polarities. Total phenolics, total flavonoids DPPH• scavenging, ABTS•+ scavenging, and cytotoxicity of A. lactiflora were assessed. Anti-inflammatory activities were evaluated by pre-treating macrophages with extract or fractions then induced inflammatory response by coconut shell pyrolysis smoke. Inflammatory responses were assessed by measuring pro-inflammatory genes expression and pro-inflammatory cytokines secretion. Among all extract and fractions of A. lactiflora, butanol fraction has the highest phenolic, flavonoid, and DPPH• scavenging activity. All extract and fractions significantly down-regulated pro-inflammatory genes expression (RelA, TNF, IL6) and decreased pro-inflammatory cytokines secretion (TNF-α, IL-6), p < 0.0001, compared with pyrolysis smoke-induced macrophages. The ethyl acetate fraction showed the highest anti-inflammatory activity in decreasing pro-inflammatory cytokines secretion. These results may prove the anti-inflammatory activities of A. lactiflora through the inhibition of the NF-κB-dependent pathway. Taken together, this study first reported the anti-inflammatory activities of A. lactiflora. Thus, the plant can be used to prevent and treat inflammatory responses caused by highly oxidative pyrolysis smoke released from the re-utilization of agro-industrial leftovers.

Phenolic Profile of Nipa Palm Vinegar and Evaluation of Its Antilipidemic Activities.

Obesity and overweight are strongly associated with dyslipidemia which can promote the development of cardiovascular diseases. Recently, natural products have been suggested as alternative compounds for antioxidant and antilipidemic activity. The objective of this study was to determine the phenolic compounds and assess the inhibitory activities on pancreatic lipase, cholesterol esterase, and cholesterol micellization of nipa palm vinegar (NPV). Total phenolic content was assessed and phenolic compounds were determined using the Folin-Ciocalteu assay and liquid chromatography-mass spectrometry (LC-MS), respectively. Pancreatic lipase and cholesterol esterase inhibitory activities of the NPV were measured using enzymatic colorimetric assays. The formation of cholesterol micelles was assessed using a cholesterol assay kit. The phenolic content of NPV was 167.10 ± 10.15 µg GAE/mL, and LC-MS analyses indicated the presence of gallic acid, isoquercetin, quercetin, catechin, and rutin as bioactive compounds. Additionally, the NPV inhibited pancreatic lipase and cholesterol esterase activities in a concentration-dependent manner. Moreover, the NPV also suppressed the formation of cholesterol micellization. These results suggest that phenolic compounds, especially gallic acid, isoquercetin, quercetin, catechin, and rutin, from NPV may be the main active compounds with possible cholesterol-lowering effects through inhibition of pancreatic lipase and cholesterol esterase activities as well as the inhibition of solubility of cholesterol micelles. Therefore, NPV may delay postprandial dyslipidemia, and it could be used as a natural source of bioactive compounds with antilipidemic activity. However, NPV should be extensively evaluated by animal and clinical human studies.

Anti melanogenic effect of Croton roxburghii and Croton sublyratus leaves in α-MSH stimulated B16F10 cells.

Croton roxburghii and Croton sublyratus have been used as skin treatments in traditional medicine. The objective of the present study was to investigate the antimelanogenic effect of ethanol extracts of Croton roxburghii (CRE) and Croton sublyratus (CSE) leaves on cellular melanin content and cellular tyrosinase activity as mediated by the action of microthalmia transcription factor (MITF) and melanogenic enzymes. Croton roxburghii and Croton sublyratus leaves were extracted by petroleum ether, dichloromethane and absolute ethanol, sequentially. The ethanolic crude extracts were examined for antimelanogenic activity by their ability to decrease melanin content and cellular tyrosinase activity in alpha-melanocyte-stimulating hormone-stimulated B16F10 melanoma cells. In addition, the extracts were evaluated to determine a plausible mechanism of melanogenesis suppression through determining the activation of MITF transcription factor and melanogenic proteins (tyrosinase, tyrosinase-related protein 1 or TRP-1 and tyrosinase-related protein 2 or TRP-2) at the transcriptional and translation levels in α-MSH-induced B16F10 cells. Upon treatment with CRE and CSE, the cells showed significant decreases in melanin content and cellular tyrosinase activity. CRE and CSE also suppressed MITF, tyrosinase, TRP-1 and TRP-2 at the transcription and translation levels in α-MSH-stimulated melanin biosynthesis in B16F10 cells. Our finding shows that CRE and CSE inhibit melanin content and cellular tyrosinase activity through suppressing MITF and melanogenic enzymes. CRE and CSE may be useful to combine with skin whitening agents for cosmetic uses.

In situ paper-based 3D cell culture for rapid screening of the anti-melanogenic activity.

Recently, paper has gained traction in the biotechnology research field due to its ability to be a substrate for 3D cell culture. In this work, we demonstrate the application of paper-based 3D cell culture for rapid and easy screening of the effect of natural compounds on melanin production. Whatman No. 1 filter paper was used as the substrate for B16F10 melanoma cell culture. The use of paper is beneficial for supporting the 3D structure of cells, which makes the result more reliable due to the similarity to in vivo conditions. Furthermore, paper is beneficial for melanin observation due to melanin's black color, which is easily in situ visualized after it is cultured on white paper. Matrigel was used to encapsulate cells before being pipetted onto the paper to prevent the passing of cells through paper pores. The intensity of melanin can then be observed with the naked eye and analyzed by scanning the paper. The analysis process took only 20 minutes, which is faster than that of the conventional absorbance spectroscopy, owing to the elimination of centrifugation, melanin solubilization, and the absorbance measurement step. The color intensity on the paper showed a direct proportion with increased α-MSH concentrations, confirming that the color on the paper was melanin. The 3D structure of cells was confirmed by using a scanning electron microscope. To demonstrate the application of the paper-based scaffold, paper-based 3D cell culture was used for screening the effects of Kojic acid and Arbutin on melanin production, which showed increased anti-melanogenesis effects with increased concentrations of natural compounds. High cell viability was observed over 120 hours. In conclusion, the developed paper-based scaffold can be used for screening the effect of natural compounds on melanin production, as a rapid and simple method with low cost.

Thai plants with high antioxidant levels, free radical scavenging activity, anti-tyrosinase and anti-collagenase activity.

BACKGROUND: Ultraviolet radiation from sunlight induces overproduction of reactive oxygen species (ROS) resulting in skin photoaging and hyperpigmentation disorders. Novel whitening and anti-wrinkle compounds from natural products have recently become of increasing interest. The purpose of this study was to find products that reduce ROS in 14 Thai plant extracts. METHODS: To determine total phenolic and flavonoid content, antioxidant activity, anti-tyrosinase activity and anti-collagenase activity, we compared extracts of 14 Thai plants prepared using different solvents (petroleum ether, dichloromethane and ethanol). Antioxidant activities were determined by DPPH and ABTS assays. RESULTS: Total phenolic content of the 14 Thai plants extracts was found at the highest levels in ethanol followed by dichloromethane and petroleum ether extracts, respectively, while flavonoid content was normally found in the dichloromethane fraction. Scavenging activity ranged from 7 to 99% scavenging as assessed by DPPH and ABTS assays. The ethanol leaf extract of Ardisia elliptica Thunb. had the highest phenolic content, antioxidant activity and collagenase inhibition, while Cassia alata (L.) Roxb. extract had the richest flavonoid content. Interestingly, three plants extracts, which were the ethanolic fractions of Annona squamosa L., Ardisia elliptica Thunb. and Senna alata (L.) Roxb., had high antioxidant content and activity, and significantly inhibited both tyrosinase and collagenase. CONCLUSION: Our finding show that the ethanol fractions of Annona squamosa L., Ardisia elliptica Thunb. and Senna alata (L.) Roxb. show promise as potential ingredients for cosmetic products such as anti-wrinkle agents and skin whitening products.