Inhibition of melanogenesis and oxidation by protocatechuic acid from Origanum vulgare (oregano)

Exploring the underlying pharmacological, immunomodulatory, and anti-inflammatory mechanisms of phytochemicals against wounds: a molecular insight

BACKGROUND

Numerous cellular, humoral, and molecular processes are involved in the intricate process of wound healing.

PHARMACOLOGICAL RELEVANCE

Numerous bioactive substances, such as ß-sitosterol, tannic acid, gallic acid, protocatechuic acid, quercetin, ellagic acid, and pyrogallol, along with their pharmacokinetics and bioavailability, have been reviewed. These phytochemicals work together to promote angiogenesis, granulation, collagen synthesis, oxidative balance, extracellular matrix (ECM) formation, cell migration, proliferation, differentiation, and re-epithelialization during wound healing.

FINDINGS AND NOVELTY

To improve wound contraction, this review delves into how the application of each bioactive molecule mediates with the inflammatory, proliferative, and remodeling phases of wound healing to speed up the process. This review also reveals the underlying mechanisms of the phytochemicals against different stages of wound healing along with the differentiation of the in vitro evidence from the in vivo evidence There is growing interest in phytochemicals, or plant-derived compounds, due their potential health benefits. This calls for more scientific analysis and mechanistic research. The various pathways that these phytochemicals control/modulate to improve skin regeneration and wound healing are also briefly reviewed. The current review also elaborates the immunomodulatory modes of action of different phytochemicals during wound repair.

Multifunctional protocatechuic acid-polyacrylic acid hydrogel adhesives for wound dressings

Multifunctional hydrogel adhesives are highly desirable in wound healing applications, yet their preparation often requires complex material system design to achieve. Herein, a straightforward one-pot two-step polymerization method is developed to prepare adhesive hydrogels for wound dressing based on protocatechuic acid (PCA), polyacrylic acid (PAA), and polyamidoamine-epichlorohydrin (PAE), where PCA provides the catechol groups for strong adhesion, PAA serves as the primary polymer matrix, and PAE acts as a bridge connecting PCA and PAA. This design results in a PAA-PAE-PCA hydrogel having a remarkable instant 90-degree peeling interfacial toughness of 431 J m-2 on porcine skin, which is further amplified to 615 J m-2 after 30 minutes. The hydrogel also possesses the desired features for wound dressing, such as self-healing, antioxidant, anti-UV and antibacterial properties, good cytocompatibility, strong adhesion in use and weak adhesion on removal, as well as reversible and wet adhesion. Finally, in vivo data reveal that the PAA-PAE-PCA hydrogels can significantly accelerate wound healing, as evidenced by a noticeable reduction in the wound area and a diminished inflammatory response. Collectively, these results endorse the obtained multifunctional hydrogel as a promising candidate for wound healing and related fields.

Mechanochemical Synthesis and Three-Dimensional Electron Diffraction Structure Solution of a Novel Cu-Based Protocatechuate Metal-Organic Framework

Mechanochemical synthesis is a powerful approach to obtain new materials, limiting costs, and times. However, defected and submicrometrical-sized crystal products make critical their characterization through classical single-crystal X-ray diffraction. A valid alternative is represented by three-dimensional (3D) electron diffraction, in which a transmission electron microscope is used, like a diffractometer. This work matches a green water-based mechanochemical synthesis and 3D electron diffraction to obtain and characterize a Cu-based protocatechuate metal-organic framework (PC-MOF). Its structure has been fully refined through dynamical diffraction theory, and free water molecules could be detected in the channels of the framework. Thermal characterization, focused on the dehydration profile determination, leads to the formation of a novel high-temperature 2D coordination polymer, fully solved with 3D electron diffraction data. At last, the strong activity of the PC-MOF against cationic dyes like methylene blue has been reported.

Investigation on wound healing effect of Mediterranean medicinal plants and some related phenolic compounds: A review

ETHNOPHARMACOLOGICAL RELEVANCE

The human skin constitutes a biological barrier against external stress and wounds can reduce the role of its physiological structure. In medical sciences, wounds are considered a major problem that requires urgent intervention. For centuries, medicinal plants have been used in the Mediterranean countries for many purposes and against wounds.

AIM OF THIS REVIEW

Provides an outlook on the Mediterranean medicinal plants used in wound healing. Furthermore, the wound healing effect of polyphenolic compounds and their chemical structures are also summarized. Moreover, we discussed the wound healing process, the structure of the skin, and the current therapies in wound healing.

MATERIALS AND METHODS

The search was performed in several databases such as ScienceDirect, PubMed, Google Scholar, Scopus, and Web of Science. The following Keywords were used individually and/or in combination: the Mediterranean, wound healing, medicinal plants, phenolic compounds, composition, flavonoid, tannin.

RESULTS

The wound healing process is distinguished by four phases, which are respectively, hemostasis, inflammation, proliferation, and remodeling. The Mediterranean medicinal plants are widely used in the treatment of wounds. The finding showed that eighty-nine species belonging to forty families were evaluated for their wound-healing effect in this area. The Asteraceae family was the most reported family with 12 species followed by Lamiaceae (11 species). Tunisia, Egypt, Morocco, and Algeria were the countries where these plants are frequently used in wound healing. In addition to medicinal plants, results showed that nineteen phenolic compounds from different classes are used in wound treatment. Tyrosol, hydroxytyrosol, curcumin, luteolin, chrysin, rutin, kaempferol, quercetin, icariin, morin, epigallocatechin gallate, taxifolin, silymarin, hesperidin, naringin, isoliquiritin, puerarin, genistein, and daidzein were the main compounds that showed wound-healing effect.

CONCLUSION

In conclusion, medicinal plants and polyphenolic compounds provide therapeutic evidence in wound healing and for the development of new drugs in this field.

Novel assays for quality evaluation of XueBiJing: Quality variability of a Chinese herbal injection for sepsis management

XueBiJing is an intravenous five-herb injection used to treat sepsis in China. The study aimed to develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS)- or liquid chromatography-ultraviolet (LC-UV)-based assay for quality evaluation of XueBiJing. Assay development involved identifying marker constituents to make the assay therapeutically relevant and building a reliable one-point calibrator for monitoring the various analytes in parallel. Nine marker constituents from the five herbs were selected based on XueBiJing's chemical composition, pharmacokinetics, and pharmacodynamics. A selectivity test (for “similarity of response”) was developed to identify and minimize interference by non-target constituents. Then, an intercept test was developed to fulfill “linearity through zero” for each analyte (absolute ratio of intercept to C response, <2%). Using the newly developed assays, we analyzed samples from 33 batches of XueBiJing, manufactured over three years, and found small batch-to-batch variability in contents of the marker constituents (4.1%–14.8%), except for senkyunolide I (26.5%).

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To make assays therapeutically relevant, criteria were proposed for defining herbal medicine efficacy & selecting analytes.

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Two tests were developed to build a one-point assay calibrator for the simultaneous monitoring of various analytes.

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Variability among 3-year batches of XueBiJing was evaluated for the first time using the therapeutically relevant assays.

The potential of Streptococcus thermophiles (TCI633) in the anti-aging

BACKGROUND

Streptococcus thermophilus (TCI633) is a probiotic that has been newly isolated from human breast milk, and it can produce hyaluronic acid (HA) when colonizing the gastrointestinal (GI) tract of rodents and humans. A recent study has the established that TCI633 can alleviate synovial tissue inflammation and has potential to mitigate the progression of osteoarthritis.

OBJECTIVE

TCI633 has not been available for use in skincare and this preliminary clinical study will assess its improvement of the skin.

METHODS

In this study, DNA protection, Hyaluronidase assay, cell viability, and collagen synthesis on human fibroblasts of TCI633 were assessed. Subjects were enrolled in this clinical study and randomly assigned to the TCI633 or placebo group. Each subject was informed to intake two tablets daily for 8 weeks. Each subject was required to undergo skin condition inspection at weeks 0, 4, and 8 and hematology tests to monitor HA, superoxide dismutase (SOD) and catalase levels, and kidney and liver function at weeks 0 and 8.

RESULTS

The effects of TCI633 supplementation, including the promotion of skin cell proliferation, the increase of their collagen content, their protection against DNA damage, and the inhibition of hyaluronidase activities, are investigated. Subjects were recruited for an 8-week long clinical trial to confirm the efficacy of TCI633 in improving the serum biochemical HA, SOD and catalase levels, and anti-skin age markers.

CONCLUSIONS

This work provides an alternative approach to improving health, indicating the potential of TCI633 supplementation to delay the aging of skin and improve its condition.

Targeting HMGB1/TLR4/NF-κB signaling pathway by protocatechuic acid protects against l-arginine induced acute pancreatitis and multiple organs injury in rats

Acute pancreatitis (AP) is a common pancreatic inflammation associated with substantial morbidity and mortality. AP may be mild or severe which can spread systemically causing multiple organs failure (MOF) and even death. In the current study, protocatechuic acid (PCA), a natural phenolic acid, was investigated for its possible protective potential against L-arginine induced AP and multiple organs injury (MOI) in rats. AP was induced by L-arginine (500 mg/100 g, ip). Two dose levels of PCA were tested (50 and 100 mg/kg, oral, 10 days before L-arginine injection). PCA successfully protected against L-arginine induced AP and MOI that was manifested by normalizing pancreatic, hepatic, pulmonary, and renal tissue architecture and restoring the normal values of pancreatic enzymes (amylase and lipase), serum total protein, liver enzymes (alanine transaminase (ALT) and aspartate transaminase (AST)) and kidney function biomarkers (blood urea nitrogen (BUN) and serum creatinine (Cr)) that were significantly elevated upon L-arginine administration. Additionally, PCA restored balanced oxidant/antioxidants status that was disrupted by L-arginine and normalized pancreatic levels of inducible nitric oxide synthase (iNOS) and nitric oxide (NO) content. Moreover, PCA significantly decreased L-arginine induced elevation in pancreatic high motility group box protein 1 (HMGB1), toll like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), nuclear factor kappa B (NF-κB), tumor necrosis factor- α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) expression. PCA significantly ameliorated L-arginine-induced AP and MOI through its anti-inflammatory and antioxidant effects. HMGB1/TLR4/NF-κB was the major pathway involved in the observed protective potential.

Dependence of the Concentration of Bioactive Compounds in Origanum vulgare on Chemical Properties of the Soil

The aim of this study was to determine the dependence of the total phenolic, flavonoid, and extractive content in extracts of Origanum vulgare L. on the soil pH, humus, total nitrogen (N_total), and plant-available/mobile phosphorus (P₂O₅), as well as potassium (K₂O), total calcium (Ca), magnesium (Mg), and sodium (Na) concentrations. Experimental fields were formed in four locations in Lithuania. Soil and perennial O. vulgare samples were taken at three sites of each experimental field. A total of 12 samples of soil and 12 samples of the tested plant were collected and analyzed. The concentrations of bioactive compounds in plants are significantly (p < 0.05–0.01) affected by some chemical properties of the soil: the total phenolic content was reliably correlated with the soil pH, N_total, Ca, Mg, and P₂O₅; the flavonoid content was correlated with the soil P₂O₅, K₂O, Mg, and Na; and the extractive content was correlated with the soil humus, N_total, and Na. The obtained results are useful for the development of the commercial cultivation of O. vulgare.

UHPLC-DAD Characterization of Origanum vulgare L. from Atacama Desert Andean Region and Antioxidant, Antibacterial and Enzyme Inhibition Activities

The Lamiaceae family is an important source of species among medicinal plants highly valued for their biological properties and numerous uses in folk medicine. Origanum is one of the main genera that belong to this family. The purpose of the study was to determine the phenolic composition of the Origanum vulgare extract and evaluate the antimicrobial, antioxidant, and inhibitory activities of this species that grows in the Andean region of the Atacama Desert. High-performance liquid chromatography was performed to determine the main phenols. Rosmarinic acid was identified as the predominant phenolic compound in this species (76.01 mg/100 g DW), followed by protocatechuic acid, which to our knowledge, no previous study reported similar concentrations in O. vulgare. The oregano extract exhibited a content of total phenolic (3948 mg GAE/100 g DW) and total flavonoid (593 mg QE/100 g DW) with a higher DPPH antioxidant activity (IC₅₀ = 40.58 µg/mL), compared to the same species grown under other conditions. Furthermore, it was found to inhibit α-glucosidase activity with an IC₅₀ value (7.11 mg/mL) lower than acarbose (129.32 mg/mL). Pseudomonas syringae and Pantoea agglomerans (both MIC 0.313 mg/mL and MBC 1.25 mg/mL) were the bacteria most susceptible to oregano extract with the lowest concentration necessary to inhibit bacterial growth. These results open the door for the potential use of this plant to manage chronic diseases, and they expand the knowledge of the species cultivated in arid environmental conditions.

The Anti-Melanogenesis Effect of 3,4-Dihydroxybenzalacetone through Downregulation of Melanosome Maturation and Transportation in B16F10 and Human Epidermal Melanocytes

The biosynthesis pathway of melanin is a series of oxidative reactions that are catalyzed by melanin-related proteins, including tyrosinase (TYR), tyrosinase-related protein-1 (TRP-1), and tyrosinase-related protein-2 (TRP-2). Reagents or materials with antioxidative or free radical-scavenging activities may be candidates for anti-melanogenesis. 3,4-Dihydroxybenzalacetone (DBL) is a polyphenol isolated from fungi, such as Phellinus obliguus (Persoon) Pilat and P. linteus. In this study, we investigated the effects and mechanisms of DBL on antioxidation and melanogenesis in murine melanoma cells (B16F10) and human epidermal melanocytes (HEMs). The results indicated that DBL scavenged 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radicals, and exhibited potent reducing power, indicating that it displays strong antioxidative activity. DBL also inhibited the expression of TYR, TRP-1, TRP-2, and microphthalmia-related transcription factor (MITF) in both the cells. In addition, DBL inhibited hyperpigmentation in B16F10 and HEMs by regulating the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA), v-akt murine thymoma viral oncogene homolog (AKT)/glycogen synthase kinase 3 beta (GSK3β), and mitogen-activated protein kinase kinase (MEK)/extracellular regulated protein kinase (ERK) signaling pathways. DBL not only shortened dendritic melanocytes but also inhibited premelanosome protein 17 (PMEL17) expression, slowing down the maturation of melanosome transportation. These results indicated that DBL promotes anti-melanogenesis by inhibiting the transportation of melanosomes. Therefore, DBL is a potent antioxidant and depigmenting agent that may be used in whitening cosmetics.

Boolean model for melanogenesis

Melanogenesis is a highly regulated process through which the pigment melanin is produced in skin cells. Irregularities in the molecular events that govern the process of skin pigmentation can cause disorders like vitiligo. In order to understand the biology of disease progression, it is important to have an in depth understanding of intracellular events. Mathematical models provide an integrated view of intracellular signalling. There are very few models to date that incorporate intracellular processes relevant to melanogenesis and only one to our knowledge that simulates the dynamics of response to varying levels of input. Here, we report the formulation of the largest Boolean model (265 nodes) for melanogenesis to date. The model was built on the basis of a detailed interaction network graph published by Raghunath et al. Through additional manual curation of the reported interactions, we converted the graph into a set of Boolean rules, following the procedure of the first Boolean model (62 nodes) for melanogenesis published by Lee et al. Simulations show that the predicted response to varying UV levels for most of the nodes is similar to the predictions of the existing model. The greater complexity allows investigation of the sensitivity of melanin to additional nodes. We carried out perturbation analysis of the network through node deletion and constitutive activation to identify sensitivity of outcomes, and compared the nodes identified as sensitive to previous reports.

Chemical characterization and in vitro immunomodulatory effects of different extracts of moss Hedwigia ciliata (Hedw.) P. Beauv. from the Vršačke Planine Mts., Serbia

Bioactive compounds from natural sources are of great importance because of their potential pharmacological activity and tremendous structural diversity. In this study, the chemical composition of different moss extracts of Hedwigia ciliata P. Beauv. have been examined, as well as their antioxidant, antineurodegenerative/anti-neuroinflammatory, antidiabetic, and antiproliferative potential. The extracts were prepared by Soxhlet extractor using solvents of different polarity. Chemical characterization of the extracts revealed the presence of phenolics and flavonoid compounds, together with triterpenoids as secondary metabolites of high biological activity. Significant antioxidant properties of all the extracts were exhibited using the β-carotene assay. The highest activities were found for water:ethanol extract (with the highest inhibition rate of 96%), but also significant inhibition was measured for ethanol and ethyl acetate extracts (80% and 70%, respectively). Confirmation of biocompatibility of investigated moss extracts has been performed using normal human fibroblast cell line, MRC-5. The H. ciliata extracts exhibited significant antiproliferative activity (~ 50%) against the MDA-MB-231 (human breast adenocarcinoma cell line), which has not previously been reported elsewhere. The Griess assay confirmed the potential anti-neuroinflammatory activity of the extracts, as significant effects in reducing NO production by LPS-stimulated BV2 (normal murine microglia cell line) was observed. This data is in line with noted antineurodegenerative potential measured by the inhibition of acetylcholinesterase (with the highest inhibition rate of 60% for ethyl acetate extract) and tyrosinase (with the highest inhibition rate of 70% for ethanol extract). Additionally, the H. ciliata extracts exhibited significant antidiabetic effect mediated by α-glucosidase inhibition (with the highest inhibition rate of 80% for ethyl acetate extract). The obtained data suggest the presence of immunomodulatory effects of the moss extracts in vitro, which allows the design of new experiments aimed at detecting and characterizing bioactive compounds of the extracts and additionally elucidate detailed mechanisms of their effects.

Effects of protocatechuic acid on ameliorating lipid profiles and cardio-protection against coronary artery disease in high fat and fructose diet fed in rats

A coronary heart disease leads to increase in obesity and metabolic dysfunction. Protocatechuic acid (PCA), due to its antioxidant, anti-inflammatory, neuro protective activities was found efficient as cardio-protective in coronary heart disease. Our study investigated hypolipidemic and cardioprotective effects of protocatechuic acid in the coronary artery disease induced by high fat and fructose diet (HFD) rat models. A diet rich in fat and fructose was fed to male Wistar rats prior to the start of experimental procedures. Serum lipid levels and hepatic triglycerides (TG) and total cholesterol (TC) levels were examined and analyzed. Both in vitro an in vivo pancreatic lipase activity was determined as well. Histopathological examination was performed and their results were noted. Noteworthy reduction of serum lipid levels and hepatic TG and TC levels was seen in groups treated with simvastatin (SIM; 20 mg/kg) and PCA (50 and 100 mg/kg) in comparison to HFD groups. Pancreatic lipase activity was reduced in the SIM group and the group treated with doses of PCA (50 and 100 mg/kg). A marked increase in gain in body weight per week (P<0.05) was achieved in HFD group. Coronary risk index (CRI) and Atherogenic index of plasma (AIP) showed decreased index values after treatments with SIM and PCA (50 and 100 mg/kg), respectively. Our findings confirmed the efficacious cardio-protective and hypolipidaemic activities of protocatechuic acid in coronary artery disease induced in rats with fat and fructose rich diet.

Protocatechuic Aldehyde Attenuates UVA-Induced Photoaging in Human Dermal Fibroblast Cells by Suppressing MAPKs/AP-1 and NF-κB Signaling Pathways

Ultraviolet radiation (UV) is a major causative factor of DNA damage, inflammatory responses, reactive oxygen species (ROS) generation and a turnover of various cutaneous lesions resulting in skin photoaging. The purpose of this study is to investigate the protective effect of protocatechuic aldehyde (PA), which is a nature-derived compound, against UVA-induced photoaging by using human dermal fibroblast (HDF) cells. In this study, our results indicated that PA significantly reduced the levels of intracellular ROS, nitric oxide (NO), and prostaglandins-E₂ (PGE₂) in UVA-irradiated HDF cells. It also inhibited the levels of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression. Besides, PA significantly suppressed the expression of matrix metalloproteinases-1 (MMP-1) and pro-inflammatory cytokines and promoted collagen synthesis in the UVA-irradiated HDF cells. These events occurred through the regulation of activator protein 1 (AP-1), nuclear factor-κB (NF-κB), and p38 signaling pathways in UVA-irradiated HDF cells. Our findings suggest that PA enhances the protective effect of UVA-irradiated photoaging, which is associated with ROS scavenging, anti-wrinkle, and anti-inflammatory activities. Therefore, PA can be a potential candidate for the provision of a protective effect against UVA-stimulated photoaging in the pharmaceutical and cosmeceutical industries.

The Applications of Origanum Vulgare and Its Derivatives in Human, Ruminant and Fish Nutrition – A Review

Origanum vulgare L. is an aromatic enduring herb that belongs to Lamiaceae family. The bioactive constituents of this herb, such as carvacrol and thymol possess several medicinal properties, such as antioxidant, antidiabetic, anti-inflammatory, antimicrobial, antiviral, antiparasitic, anti-neoplastic, and immune modulatory. Moreover, it is considered a standard natural, less toxic, and residue free feed additive, that is successfully used in livestock and fish. Additionally, in human, Origanum vulgare is extensively used with promising health benefits against respiratory, digestive and urinary disorders. This review casts light on description, chemical composition and structure of Origanum vulgare, as well as its therapeutic applications in human and its biological activities in ruminants and fish, data that will be possibly useful for physiologists, nutritionists and veterinarians.

The effects of aqueous extract of Origanum vulgare on learning and memory in male rats

Introduction: The effectiveness of antioxidants on learning and memory improvement has been shown, previously. Due to the high level of antioxidants, available in Origanum vulgare, the present experiment aimed to examine the effect of aqueous extract of O. vulgare on passive avoidance learning (PAL) in male Wistar rats. Methods: This study was performed on 30 male Wistar rats weighing 250 to 290 g. The rats were randomly assigned into five groups (n=6), as follows: the control, sham (saline), and three groups treated with different doses of O. vulgare extract (150, 250, and 350 mg/kg). The saline or extract was administered via daily oral gavage for 14 days. The groups were then subjected to the passive avoidance task, and their behaviors were recorded. The rats’ locomotor activity was also measured using the open field test. Results: The number of trials to acquisition was significantly lower in the "O. vulgare (350 mg/ kg)" group than the control group. The step-through latency and the time spent in the dark compartment in the retention test, was significantly higher and lower in the "O. vulgare (250 and 350 mg/kg)" groups than the control group, respectively. No significant differences were found in the distances traveled among the experimental groups in the open field test. Conclusion: Aqueous extract of O. vulgare can enhance learning and memory. The high levels of antioxidants in O. vulgare extract may be responsible for its effectiveness in learning and memory.

Biological Efficacy of Essential Oils and Plant Extracts of Cultivated and Wild Ecotypes of Origanum vulgare L

Current study describes discrepancy in biological efficacy of methanolic and ethanolic extracts and essential oil procured from cultivated and wild accessions of Origanum vulgare. Simultaneously, quantification of carvacrol, thymol, caryophyllene, ocimene, and terpinen-4-ol contents was determined via GC-MS and GC in both accessions. The results revealed significantly a higher antioxidant potential by methanolic extracts displaying IC₅₀ of 19.9 μg/ml compared to essential oil with IC₅₀ of 10 μg/ml, and ethanolic extracts were found to be less effective even at the concentration of 3 μg/ml. However, essential oil from wild and cultivated accessions of O. vulgare exhibited significantly high antimicrobial activity against all 39 bacteria, 16 fungi, and 2 yeast species tested due to higher concentrations of carvacrol and thymol as revealed by GC analysis. Inhibition of tyrosinase activity in a C6 cell line displayed 81.0%–87.0% depigmentation potential of the methanolic extracts, while ethanolic extracts revealed a maximum of 88.54–99.02% inhibition of reactive oxygen species (ROS) in H₂O₂-treated cells. Hence, the study determines efficacy of essential oil against microbial pathogenesis, methanolic extracts as potent depigmentation agents, and ethanolic extracts as potent free radical scavenger.

Chemical characterization, antioxidant, enzyme inhibitory and cytotoxic properties of two geophytes: Crocus pallasii and Cyclamen cilicium

The Crocus and Cyclamen genus have been reported to possess diverse biological properties. In the present investigation, two geophytes from these genus, namely Crocus pallasi and Cyclamen cilicium have been studied. The in vitro antioxidant, enzyme inhibitory, and cytotoxic effects of the methanol extracts of Crocus pallasii and Cyclamen cilicium aerial and underground parts were investigated. Antioxidant abilities of the extracts were investigated via different antioxidant assays (metal chelating, radical quenching (ABTS and DPPH), reducing power (CUPRAC and FRAP) and phosphomolybdenum). Cholinesterases, amylase, tyrosinase, and glucosidase were used as target enzymes for detecting enzyme inhibitory abilities of the samples. Regarding the cytotoxic abilities, breast cancer cell lines (MDA-MB 231 and MCF-7) and prostate cancer cell lines (DU-145) were used. The flowers extracts of Crocus pallasii and C. cilicium possessed the highest flavonoid content. The highest phenolic content was recorded from C. cilicium root extract (47.62 mg gallic acid equivalent/g extract). Cyclamen cilicium root extract showed significantly (p < 0.05) high radical scavenging (94.28 and 139.60 mg trolox equivalent [TE]/g extract, against DPPH and ABTS radicals, respectively) and reducing potential (173.30 and 109.53 mg TE/g extract, against CUPRAC and FRAP, respectively). The best acetylcholinesterase, glucosidase and tyrosinase inhibition was observed in C. cilicium root (4.46 mg GALAE/g; 15.75 mmol ACAE/g; 136.99 mg KAE/g, respectively). Methanolic extracts of C. pallasii and C. cilicium showed toxicity against breast cancer cell lines. In light of the above findings, C. cilicium might be considered as an interesting candidate in the development of anti-cancer agent coupled with antioxidant properties.

Reversing UVB-induced photoaging with Hibiscus sabdariffa calyx aqueous extract

BACKGROUND

Hibiscus sabdariffa is commonly used in daily life and its extract is applied widely in food and cosmetics. However, it has not been evaluated for its anti-aging effects.

RESULTS

Hibiscus sabdariffa calyx aqueous extract (HSCAE) has shown potential collagenase activity suppression effects, together with tyrosinase activity inhibition, and anti-oxidation as a free radical scavenger. The current investigation demonstrated that HSCAE was not cytotoxic in skin fibroblasts, and it significantly decreased ultraviolet B (UVB)-induced reactive oxygen species (ROS) on a flow cytometry assay. Moreover, HSCAE reduced matrix metalloproteinase (MMP) expression, increased tissue inhibition of metalloproteinase (TIMP)-1 level, and enhanced collagen content by inhibiting collagenase activity. It also blocked mRNA and protein expressions of melanin production pathway key factors, including the microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 (TRP-1), and dopachrome tautomerase-2 (TRP-2).

CONCLUSION

These results demonstrated, for the first time, the potential of HSCAE as a natural antioxidant with the ability to maintain collagen production and to decrease melanin syntheses under UVB radiation, for anti-aging effects. © 2019 Society of Chemical Industry.

The role and mechanism of Asian medicinal plants in treating skin pigmentary disorders

ETHNOPHARMACOLOGICAL RELEVANCE

Chloasma, senile plaques, vitiligo and other pigmentary disorders seriously affect patients' appearance and life quality. Medicinal plant is the product of long-term medical practice worldwide, with the advantages of outstanding curative properties and less side effects. Recently, research were made to explore the value of medicinal plants in the treatment of pigmentary disorders, and remarkable results were achieved.

AIM OF THE REVIEW

This review outlines the current understanding of the role and potential mechanisms of medicinal plants (including active ingredients, extracts and prescriptions) in pigmentary disorders, especially Chinese medicinal plants, provides the preclinical evidence for the clinical benefits. This study hopes to provide comprehensive information and reliable basis for exploring new therapeutic strategies of plant drugs in the treatment of skin pigmented diseases.

METHODS

The literature information was obtained from the scientific databases (up to Oct, 2017), mainly from the PubMed, Web of Science and CNKI databases, and was to identify the experimental studies on the regulating melanogenesis role of the active agents from herbal medicine and the involved mechanisms. The search keywords for such work included: "pigmentary" or "pigmentation", "melanogenesis", and "traditional Chinese medicine" or "Chinese herbal medicine", "herb", "medicinal plant".

RESULTS

We summarized the function of medicinal plants involved in melanogenesis, especially Chinese medicine. It was reported that the active ingredients, extracts, or prescriptions of medicinal plants can regulate the expression of genes related to melanogenesis by affecting the signaling pathways such as MAPK and PKA, thereby regulating pigment synthesis. Some of them can promote melanogenesis (such as isoliquiritigenin, geniposide; Cornus officinalis Siebold & Zucc., Eclipta prostrata (L.) L.; the Bairesi complex prescription, etc.). While others have the opposite effect (such as biochanin A, Gomisin N; Panax ginseng C.A. Meyer, Nardostachys chinensis Bat.; Sanbaitang, etc.).

CONCLUSION

Asian medicinal plants, especially their active ingredients, have multilevel effects on melanogenesis by regulating melanogenesis-related genes or signaling pathways. They are of great clinical value for the treatment of skin pigmentary disorders. However, the experimental effect, safety, and functional mechanism of the medicinal plants require further determination before studying their clinical efficacy.

Sesamol Inhibited Ultraviolet Radiation-Induced Hyperpigmentation and Damage in C57BL/6 Mouse Skin

Melanin is synthesized through a series of oxidative reactions initiated with tyrosine and catalyzed by melanogenesis-related proteins such as tyrosinase, tyrosinase-related protein-1 (TRP-1), dopachrome tautomerase (TRP-2), and microphthalmia-associated transcription factor (MITF). Our previous study demonstrated that sesamol inhibited melanin synthesis through the inhibition of the melanocortin 1 receptor (MC1R)/MITF/tyrosinase pathway in B16F10 cells. In this study, sesamol was applied to C57BL/6 mouse skin to understand its activity with respect to skin pigmentation. The results indicated that ultraviolet (UV) B-induced hyperpigmentation in the C57BL/6 mouse skin was significantly reduced by topical application of sesamol for 4 weeks. Sesamol reduced the melanin index and melanin content of the skin. In addition, sesamol elevated the brightness (L* value) of the skin. Sesamol also reduced UVB-induced hyperplasia of epidermis and collagen degradation in dermis. In immunohistochemical staining, topical application of sesamol reduced UVB-induced tyrosinase, TRP-1, TRP-2, and MITF expression in the epidermis of the skin. These results demonstrated that sesamol is a potent depigmenting agent in the animal model.

Interconnected PolymerS TeChnology (IPSTiC): An Effective Approach for the Modulation of 5α-Reductase Activity in Hair Loss Conditions

Hair loss represents a condition that adversely affects the social life of patients. The most common cause is androgenetic alopecia (AGA), which is a genetically determined progressive hair-loss condition involving 5α-reductase. In this study, a novel anti-baldness agent based on Interconnected PolymerS TeChnology (IPSTiC), which is an effective strategy for the delivery of bioactive molecules, was developed. This product (IPSTiC patch hair) is based on a polymeric blend consisting of high molecular weight hyaluronic acid and soybean proteins and is able to improve efficacy and stability of bioactive ingredients such as Origanum vulgare leaf extract, Camellia Sinensis leaf extract, and Capsicum Annuum fruit extract. The efficacy of the developed anti-baldness agent was investigated by performing several tests including NO radical and 5α-reductase inhibition assays, stability studies under different conditions, and in vitro diffusion studies using Franz cells. The biocompatibility of IPSTiC patch hair was also evaluated by in vitro analysis of the pro-sensitising potential and EPISKIN model. The obtained results confirmed both the efficacy and safety of IPSTiC patch hair supporting the potential use of this product in the topical treatment of AGA.

Sesamol Inhibited Melanogenesis by Regulating Melanin-Related Signal Transduction in B16F10 Cells

Melanin is synthesized through a series of interactions catalyzed by melanogenic enzymes such as tyrosinase, dopachrome tautomerase (tyrosinase-related protein-2; TRP-2), and tyrosinase-related protein-1 (TRP-1). Tyrosinase plays a key role in catalysing the initial and limiting steps of melanogenesis. The melanin that results from melanogenesis has the protective effect of absorbing ultraviolet radiation. However, overproduction of melanin, in addition to altering the appearance of skin, may lead to skin disorders such as melasma, solar lentigo, and postinflammatory hyperpigmentation. Previous studies have revealed that sesamol is a strong antioxidant and a free radical scavenger. In this study, we investigated the effects of sesamol on the regulation of melanogenesis and related mechanisms in B16F10 cells. The results indicated that sesamol inhibited tyrosinase activity and melanogenesis induced by α-melanocyte-stimulating hormone (α-MSH) in B16F10 melanoma cells. Sesamol decreased the protein level of melanocortin 1 receptor (MC1R), microphthalmia-associated transcription factor (MITF), tyrosinase, and TRP-1 by downregulating cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) pathways that had been activated by α-MSH. Sesamol increased glycogen synthase kinase 3 beta (GSK3β), protein kinase B (AKT), and extracellular signal-related kinase (ERK) phosphorylation, thus inhibiting the transcription of MITF. Sesamol also inhibited melanin synthesis and tyrosinase expression by modulating ERK, phosphoinositide 3-kinase (PI3K)/AKT, p38, and c-Jun amino-terminal kinase (JNK) signalling pathways. These results indicate that sesamol acted as a potent depigmenting agent.

Therapeutic Effects of Medicinal Plants on Cutaneous Wound Healing in Humans: A Systematic Review

The pharmaceutical industry has made great strides in providing drugs that are able to stimulate the healing process, but only 1-3% of all drugs that are listed in Western pharmacopoeias are intended for use on the skin or cutaneous wounds. Of these, at least one-third are obtained from plants. We sought to review the therapeutic effects of medicinal plants on human skin lesions. For this systematic review, we searched the PubMed, Scopus, and Web of Science databases to identify clinical trials that were published from 1997 to 2017. We reviewed studies that described the use of medicinal plants for the treatment of skin lesions in humans. Ten studies were selected, eight of which were published from 2007 to 2016, with a total of 503 patients. Among the plant species that were used for the treatment of human skin lesions, 12 belonged to 11 families and were included in the analysis. All of the plant species that were studied presented high therapeutic potential for the treatment of cutaneous lesions.

Protocatechuic Acid from Pear Inhibits Melanogenesis in Melanoma Cells

Despite the critical role of melanin in the protection of skin against UV radiation, excess production of melanin can lead to hyperpigmentation and skin cancer. Pear fruits are often used in traditional medicine for the treatment of melasma; therefore, we investigated the effects of pear extract (PE) and its component, protocatechuic acid (PCA), on melanogenesis in mouse melanoma cells. We found that PE and PCA significantly suppressed melanin content and cellular tyrosinase activity through a decrease in the expression of melanogenic enzymes and microphthalmia-associated transcription factor (Mitf) in α-melanocyte stimulating hormone-stimulated mouse melanoma cells. Moreover, PCA decreased cyclic adenosine monophosphate (cAMP) levels and cAMP-responsive element-binding protein phosphorylation, which downregulated Mitf promoter activation and subsequently mediated the inhibition of melanogenesis. These results suggested that pear may be an effective skin lightening agent that targets either a tyrosinase activity or a melanogenic pathway.

Ethyl acetate extract from Panax ginseng C.A. Meyer and its main constituents inhibit α-melanocyte-stimulating hormone-induced melanogenesis by suppressing oxidative stress in B16 mouse melanoma cells

ETHNOPHARMACOLOGICAL RELEVANCE

Hyperpigmentation disease involves darkening of the skin color due to melanin overproduction. Panax ginseng C.A. Meyer is a well-known traditional Chinese medicine and has a long history of use as a skin lightener to inhibit melanin formation in China, Korea and some other Asian countries. However, the constituents and the molecular mechanisms by which they affect melanogenesis are not fully clear.

AIM OF THE STUDY

The purpose of this study was to identify the active ingredient in Panax ginseng C.A. Meyer extract that inhibits mushroom tyrosinase activity and to investigate the antioxidative capacity and molecular mechanisms of the effective extract on melanogenesis in B16 mouse melanoma cells.

MATERIALS AND METHODS

Aqueous extracts of Panax ginseng C.A. Meyer were successively fractionated with an equal volume of chloroform, ethyl acetate, and n-butyl alcohol to determine the effects by examining the activity of mushroom tyrosinase. The effective fraction was analyzed using HPLC and LC-MS. The antioxidative capacity and the inhibitory effects on melanin content, cell intracellular tyrosinase activity, and melanogenesis protein levels were determined in α-melanocyte-stimulating hormone (α-MSH)-treated B16 mouse melanoma cells.

RESULTS

The ethyl acetate extract from Panax ginseng C.A. Meyer (PG-2) had the highest inhibiting effect on mushroom tyrosinase, mainly contained phenolic acids, including protocatechuic acid, vanillic acid, p-coumaric acid, salicylic acid, and caffeic acid, and exhibited apparent antioxidant activity in vitro. PG-2 and its main constituents significantly decreased melanin content, suppressed cellular tyrosinase activity, and reduced expression of tyrosinase protein to inhibit B16 cells melanogenesis induced by α-MSH, and no cytotoxic effects were observed. They also inhibited cellular reactive oxygen species (ROS) generation, increased superoxide dismutase (SOD) activity and glutathione (GSH) level in α-MSH-treated B16 cells effectively. And those activities of its main constituents could reach more than 80% of PG-2. The ROS scavengers N-acetyl-L-cysteine (NAC) had a similar inhibitory effect on melanogenesis.

CONCLUSIONS

These results suggest that ethyl acetate extract from Panax ginseng C.A. Meyer has the highest effect on inhibiting melanogenesis, and that its main components are polyphenolic compounds, which may inhibit melanogenesis by suppressing oxidative stress. This work provides new insight into the active constituents and molecular mechanisms underlying skin-lightening effect of Panax ginseng C.A. Meyer.

N-(4-methoxyphenyl) caffeamide-induced melanogenesis inhibition mechanisms

Background

The derivative of caffeamide exhibits antioxidant and antityrosinase activity. The activity and mechanism of N-(4-methoxyphenyl) caffeamide (K36E) on melanogenesis was investigated.

Methods

B16F0 cells were treated with various concentrations of K36E; the melanin contents and related signal transduction were studied. Western blotting assay was applied to determine the protein expression, and spectrophotometry was performed to identify the tyrosinase activity and melanin content.

Results

Our results indicated that K36E reduced α-melanocyte-stimulating hormone (α-MSH)-induced melanin content and tyrosinase activity in B16F0 cells. In addition, K36E inhibited the expression of phospho-cyclic adenosine monophosphate (cAMP)-response element-binding protein, microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase-related protein-1 (TRP-1). K36E activated the phosphorylation of protein kinase B (AKT) and glycogen synthase kinase 3 beta (GSK3β), leading to the inhibition of MITF transcription activity. K36E attenuated α-MSH induced cAMP pathways, contributing to hypopigmentation.

Conclusions

K36E regulated melanin synthesis through reducing the expression of downstream proteins including p-CREB, p-AKT, p-GSK3β, tyrosinase, and TRP-1, and activated the transcription factor, MITF. K36E may have the potential to be developed as a skin whitening agent.

Biological Activities of Triterpenoids and Phenolic Compounds from Myrica cerifera Bark

Seven triterpenoids, 1 - 7, two diarylheptanoids, 8 and 9, four phenolic compounds, 10 - 13, and three other compounds, 14 - 16, were isolated from the hexane and MeOH extracts of the bark of Myrica cerifera L. (Myricaceae). Among these compounds, betulin (1), ursolic acid (3), and myricanol (8) exhibited cytotoxic activities against HL60 (leukemia), A549 (lung), and SK-BR-3 (breast) human cancer cell lines (IC₅₀ 3.1 - 24.2 μm). Compound 8 induced apoptotic cell death in HL60 cells (IC₅₀ 5.3 μm) upon evaluation of the apoptosis-inducing activity by flow cytometric analysis and by Hoechst 33342 staining method. Western blot analysis on HL60 cells revealed that 8 activated caspases-3, -8, and -9 suggesting that 8 induced apoptosis via both mitochondrial and death receptor pathways in HL60. Upon evaluation of the melanogenesis-inhibitory activity in B16 melanoma cells induced with α-melanocyte-stimulating hormone (α-MSH), erythrodiol (7), 4-hydroxy-2-methoxyphenyl β-d-glucopyranoside (13), and butyl quinate (15) exhibited inhibitory effects (65.4 - 86.0% melanin content) with no, or almost no, toxicity to the cells (85.9 - 107.4% cell viability) at 100 μm concentration. In addition, 8, myricanone (9), myricitrin (10), protocatechuic acid (11), and gallic acid (12) revealed potent DPPH radical-scavenging activities (IC₅₀ 6.9 - 20.5 μm).

Inhibition of melanogenesis by Gaillardia aristata flower extract

BACKGROUND

The purpose of the study was to determine the anti-melanogenic and anti-oxidant properties of Gaillardia aristata flower extract (GAE).

METHODS

Melanogenesis inhibition by GAE was investigated in cultivated cells and in a human skin model. In cultivated cells, the melanogenesis regulatory effect of GAE was evaluated using melanin content, intracellular tyrosinase activity and anti-oxidant characteristics. In addition, the expression of melanogenesis-related proteins was determined by western blot assay and real-time PCR.

RESULTS

GAE reduced the amount of melanin in B16F10 and normal human epidermal melanocyte cells and suppressed intracellular tyrosinase activity in a dose-dependent pattern. Also, GAE significantly decreased the expression of melanogenesis-related proteins (microphthalmia associated transcription factor, tyrosinase, tyrosinase-related protein-1, and dopachrome tautomerase). Real-time PCR results revealed a down-regulation of the mRNAs of these proteins. GAE possessed anti-oxidant characteristics as free radical-scavenging capacity and reducing power. In the three-dimensional human skin model, GAE applied to hyperpigmented skin significantly increased the degree of skin lightening within 2 weeks of treatment. The safety of GAE on human skin was confirmed.

CONCLUSIONS

These results indicate the potential of GAE for use in suppressing skin pigmentation. We proposed GAE as a new candidate of anti-melanogenic and antioxidant agents that could be used for cosmetic skin care products.

Pharmacological properties of protocatechuic Acid and its potential roles as complementary medicine

This paper reviews the reported pharmacological properties of protocatechuic acid (PCA, 3,4-dihydroxy benzoic acid), a type of phenolic acid found in many food plants such as olives and white grapes. PCA is a major metabolite of anthocyanin. The pharmacological actions of PCA have been shown to include strong in vitro and in vivo antioxidant activity. In in vivo experiments using rats and mice, PCA has been shown to exert anti-inflammatory as well as antihyperglycemic and antiapoptotic activities. Furthermore, PCA has been shown to inhibit chemical carcinogenesis and exert proapoptotic and antiproliferative effects in different cancerous tissues. Moreover, in vitro studies have shown PCA to have antimicrobial activities and also to exert synergistic interaction with some antibiotics against resistant pathogens. This review aims to comprehensively summarize the pharmacological properties of PCA reported to date with an emphasis on its biological properties and mechanisms of action which could be therapeutically useful in a clinical setting.

Protocatechuic acid exerts a cardioprotective effect in type 1 diabetic rats

Oxidative stress has been shown to play an important role in the pathogenesis of diabetes-induced cardiac dysfunction. Protocatechuic acid (PCA) is a phenolic compound, a main metabolite of anthocyanin, which has been reported to display various pharmacological properties. We proposed the hypothesis that PCA exerts cardioprotection in type 1 diabetic (T1DM) rats. T1DM was induced in male Sprague-Dawley rats by a single i.p. injection of 50 mg/kg streptozotocin (STZ) and groups of these animals received the following treatments for 12 weeks: i) oral administration of vehicle, ii) oral administration of PCA at a dose of 50  mg/kg per day, iii) oral administration of PCA at a dose of 100 mg/kg per day, iv) s.c. injection of insulin at a dose of 4 U/kg per day, and v) a combination of PCA, 100 mg/kg per day and insulin, 4 U/kg per day. Metabolic parameters, results from echocardiography, and heart rate variability were monitored every 4 weeks, and the HbA1c, cardiac malondialdehyde (MDA), cardiac mitochondrial function, and cardiac BAX/BCL2 expression were evaluated at the end of treatment. PCA, insulin, and combined drug treatments significantly improved metabolic parameters and cardiac function as shown by increased percentage fractional shortening and percentage left ventricular ejection fraction and decreased low-frequency:high-frequency ratio in T1DM rats. Moreover, all treatments significantly decreased plasma HbA1c and cardiac MDA levels, improved cardiac mitochondrial function, and increased BCL2 expression. Our results demonstrated for the first time, to our knowledge, the efficacy of PCA in improving cardiac function and cardiac autonomic balance, preventing cardiac mitochondrial dysfunction, and increasing anti-apoptotic protein in STZ-induced T1DM rats. Thus, PCA possesses a potential cardioprotective effect and could restore cardiac function when combined with insulin treatment. These findings indicated that supplementation with PCA might be helpful for the prevention and alleviation of cardiovascular complications in T1DM.

Anti-trichophyton activity of protocatechuates and their synergism with fluconazole

Dermatophytosis and superficial mycosis are a major global public health problem that affects 20–25% of the world's population. The increase in fungal resistance to the commercially available antifungal agents, in conjunction with the limited spectrum of action of such drugs, emphasises the need to develop new antifungal agents. Natural products are attractive prototypes for antifungal agents due to their broad spectrum of biological activities. This study aimed to verify the antifungal activity of protocatechuic acid, 3,4-diacetoxybenzoic, and fourteen alkyl protocatechuates (3,4-dihydroxybenzoates) against Trichophyton rubrum and Trichophyton mentagrophytes and to further assess their activities when combined with fluconazole. Susceptibility and synergism assays were conducted as described in M38-A2 (CLSI), with modifications. Three strains of Trichophyton rubrum and three strains of Trichophyton mentagrophytes were used in this work. The pentyl, hexyl, heptyl, octyl, nonyl, and decyl protocatechuates showed great fungicidal effects, with minimum inhibitory concentration (MIC) values ranging from 0.97 to 7.8 mg/L. Heptyl showed a synergistic activity (FIC index = 0.49), reducing the MIC of fluconazole by fourfold. All substances tested were safe, especially the hexyl, heptyl, octyl, and nonyl compounds, all of which showed a high selectivity index, particularly in combination with fluconazole. These ester associations with fluconazole may represent a promising source of prototypes in the search for anti-Trichophyton therapeutic agents.

Anti-melanogenic effects of δ-tocotrienol are associated with tyrosinase-related proteins and MAPK signaling pathway in B16 melanoma cells

Tocotrienols are known to possess potent antioxidant, anticancer, and cholesterol lowering activities. Being able to rapidly penetrate the skin, these vitamin E isoforms have been explored for potential treatment against melanoma. This study aimed to elucidate the mechanism involved in the anti-melanogenic effects of δ-tocotrienol (δT3) in B16 melanoma cells. Results showed that at 20 μM of δT3 significantly inhibited melanin formation and ROS generation. Treatment with δT3 also effectively suppressed the expression of melanogenesis-related proteins, including MC1R, MITF, TYRP-1, and TYRP-2. More importantly, we observed that the mitogen-activated protein kinase (MAPK) pathway was involved in mediating δT3's inhibitory effect against melanin production. Specifically, δT3 treatment markedly induced the activation of extracellular signal-regulated kinases (ERK). The use of ERK activation inhibitor (PD98059) abrogated the δT3-mediated downregulation expression melanogenesis-related proteins and restored melanin production. Furthermore, siRNA targeting ERK effectively blocked the δT3-induced repression of tyrosinase and TYRP-1 expression. These results suggest that δT3's inhibitory effect against melanogenesis is mediated by the activation of ERK signaling, thereby resulting in downstream repression of melanogenesis-related proteins and the subsequent melanin production. These data provide insight to δT3's effect and the targeting of ERK signaling for treatment against melanogenesis.

Biological activities of phenolic compounds and triterpenoids from the galls of Terminalia chebula

Nine phenolic compounds, including two phenolic carboxylic acids, 1 and 2, seven hydrolyzable tannins, 3-9, eight triterpenoids, including four oleanane-type triterpene acids, 10-13, and four of their glucosides, 14-17, isolated from a MeOH extract of the gall of Terminalia chebula Retz. (myrobalan tree; Combretaceae), were evaluated for their inhibitory activities against melanogenesis in B16 melanoma cells induced by α-melanocyte-stimulating hormone (α-MSH), against the Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol 13-acetate (TPA) in Raji cells, and against TPA-induced inflammation in mice. Their 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activities and cytotoxic activities against four human cancer cell lines were also evaluated. Compounds 6-9 and 12 exhibited potent inhibitory activities against melanogenesis (39.3-66.3% melanin content) with low toxicity to the cells (74.5-105.9% cell viability) at a concentration of 10 μM. Western-blot analysis revealed that isoterchebulin (8) reduced the protein levels of MITF (=microphtalmia-associated transcription factor), tyrosinase, and TRP-1 (=tyrosine-related protein 1), mostly in a concentration-dependent manner. Eight triterpenoids, 10-17, showed potent inhibitory effects on EBV-EA induction with the IC50 values in the range of 269-363 mol ratio/32 pmol TPA, while these compounds exhibited no DPPH scavenging activities (IC50 >100 μM). On the other hand, the nine phenolic compounds, 1-9, exhibited potent radical-scavenging activities (IC50 1.4-10.9 μM) with weak inhibitory effects on EBV-EA induction (IC50 460-518 mol ratio/32 pmol TPA). The tannin 6 and seven triterpenoids, 10-16, have been shown to inhibit TPA-induced inflammation (1 μg/ear) in mice with the ID50 values in the range of 0.06-0.33 μmol/ear. Arjungenin (10) exhibited inhibitory effect on skin-tumor promotion in an in vivo two-stage mouse-skin carcinogenesis test based on 7,12-dimethylbenz[a]anthracene (DMBA) as initiator and with TPA as promoter. Compounds 1, 2, 4, 5, 7-9, 12, and 13, against HL60 cell line, compounds 1 and 4, against AZ521 cell line, and compounds 1, 11, and 12, against SK-BR-3 cell line, showed moderate cytotoxic activities (IC50 13.9-73.2 μM).

Phenolic compounds from Origanum vulgare and their antioxidant and antiviral activities

In the present study, six new phenolic compounds (1-6) along with five known ones were isolated from the ethanol extract of the whole plants of Origanum vulgare. The structures of the new compounds were identified on the basis of extensive spectroscopic analyses (UV, IR, NMR, and HRESIMS) and acid hydrolysis. Twenty-one phenolic compounds isolated from O. vulgare in our previous and present studies were evaluated for their in vitro antioxidant activity using 2,2-diphenyl-1-picryhydrazyl (DPPH) radical-scavenging and ferric-reducing antioxidant power (FRAP) assays; twelve of them including two new compounds exhibited significant antioxidant activity comparable to that of ascorbic acid. In addition, the antiviral effects against respiratory syncytial virus (RSV), Coxsackie virus B3 (CVB3) and herpes simplex virus type 1 (HSV-1) were tested by cytopathic effect (CPE) reduction assay.

Antioxidant, anti-adipocyte differentiation, antitumor activity and anthelmintic activities against Anisakis simplex and Hymenolepis nana of yakuchinone A from Alpinia oxyphylla

Background

Alpinia oxyphylla is a common remedy in traditional Chinese medicine. Yakuchinone A is a major constituent of A. oxyphylla and exhibits anti-inflammatory, antitumor, antibacterial, and gastric protective activities.

Methods

Antioxidant and antitumor characteristics of yakuchinone A in skin cancer cells as well as novel mechanisms for the inhibition of adipocyte differentiation, cestocidal activities against Hymenolepis nana adults, and nematocidal activities against Anisakis simplex larvae are investigated.

Results

Yakuchinone A presents the ability of the removal of DPPH·and ABTS⁺ free radicals and inhibition of lipid peroxidation. Yakuchinone A suppresses intracellular lipid accumulation during adipocyte differentiation in 3 T3-L1 cells and the expressions of leptin and peroxisome proliferator-activated receptor γ (PPARγ). Yakuchinone A induces apoptosis and inhibits cell proliferation in skin cancer cells. The inhibition of cell growth by yakuchinone A is more significant for non-melanoma skin cancer (NMSC) cells than for melanoma (A375 and B16) and noncancerous (HaCaT and BNLCL2) cells. Treatment BCC cells with yakuchinone A shows down-regulation of Bcl-2, up-regulation of Bax, and an increase in cleavage poly (ADP-ribose) polymerase (PARP). This suggests that yakuchinone A induces BCC cells apoptosis through the Bcl-2-mediated signaling pathway. The anthelmintic activities of yakuchinone A for A. simplex are better than for H. nana.

Conclusions

In this work, yakuchinone A exhibits antioxidative properties, anti-adipocyte differentiation, antitumor activity, and anthelmintic activities against A. simplex and H. nana.

Brazilein from Caesalpinia sappan L. Antioxidant Inhibits Adipocyte Differentiation and Induces Apoptosis through Caspase-3 Activity and Anthelmintic Activities against Hymenolepis nana and Anisakis simplex

Brazilein, a natural, biologically active compound from Caesalpinia sappan L., has been shown to exhibit anti-inflammatory and antioxidant properties and to inhibit the growth of several cancer cells. This study verifies the antioxidant and antitumor characteristics of brazilein in skin cancer cells and is the first time to elucidate the inhibition mechanism of adipocyte differentiation, cestocidal activities against Hymenolepis nana, and reduction of spontaneous movement in Anisakis simplex. Brazilein exhibits an antioxidant capacity as well as the ability to scavenge DPPH^• and ABTS^•+ free radicals and to inhibit lipid peroxidation. Brazilein inhibited intracellular lipid accumulation during adipocyte differentiation in 3T3-L1 cells and suppressed the induction of peroxisome proliferator-activated receptor γ (PPARγ), the master regulator of adipogenesis, suggesting that brazilein presents the antiobesity effects. The toxic effects of brazilein were evaluated in terms of cell viability, induction of apoptosis, and the activity of caspase-3 in BCC cells. The inhibition of the growth of skin cancer cells (A431, BCC, and SCC25) by brazilein is greater than that of human skin malignant melanoma (A375) cells, mouse leukemic monocyte macrophage (RAW 264.7 cells), and noncancerous cells (HaCaT and BNLCL2 cells). The anthelmintic activities of brazilein against Hymenolepis nana are better than those of Anisakis simplex.

Natural Melanogenesis Inhibitors Acting Through the Down-Regulation of Tyrosinase Activity

Melanogenesis is a biosynthetic pathway for the formation of the pigment melanin in human skin. A key enzyme, tyrosinase, catalyzes the first and only rate-limiting steps in melanogenesis, and the down-regulation of enzyme activity is the most reported method for the inhibition of melanogenesis. Because of the cosmetically important issue of hyperpigmentation, there is a big demand for melanogenesis inhibitors. This encourages researchers to seek potent melanogenesis inhibitors for cosmetic uses. This article reviews melanogenesis inhibitors that have been recently discovered from natural sources. The reaction mechanisms of the inhibitors on tyrosinase activity are also discussed.