Soyasaponin Ag inhibits α‑MSH‑induced melanogenesis in B16F10 melanoma cells via the downregulation of TRP‑2

Anti-Melanogenic Effects of Lilium lancifolium Root Extract via Downregulation of PKA/CREB and MAPK/CREB Signaling Pathways in B16F10 Cells

Hyperpigmentation disorders causing emotional distress require the topical use of depigmenting agents of natural origin. In this study, the anti-melanogenic effects of the Lilium lancifolium root extract (LRE) were investigated in B16F10 cells. Consequently, a non-cytotoxic concentration of the extract reduced intracellular melanin content and tyrosinase activity in a dose-dependent manner, correlating with the diminished expression of core melanogenic enzymes within cells. LRE treatment also inhibited cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB)/microphthalmia-associated transcription factor signaling, which regulates the expression of tyrosinase-related genes. Upon examining these findings from a molecular mechanism perspective, LRE treatment suppressed the phosphorylation of protein kinase A (PKA), p38, and extracellular signal-related kinase (ERK), which are upstream regulators of CREB. In addition, L-phenylalanine and regaloside A, specifically identified within the LRE using liquid chromatography-mass spectrometry, exhibited inhibitory effects on melanin production. Collectively, these results imply that LRE potentially suppresses cAMP-mediated melanogenesis by downregulating PKA/CREB and mitogen-activated protein kinase (MAPK)/CREB signaling pathways. Therefore, it can be employed as a novel therapeutic ingredient of natural origin to ameliorate hyperpigmentation disorders.

Discovery of amphotericin B, an antifungal drug as tyrosinase inhibitor with potent anti-melanogenic activity

Tyrosinase, a rate-limiting enzyme for melanin production, has been the most efficient target for the development of depigmenting agents. Although hydroquinone, kojic acid, and arbutin are the most well-known tyrosinase inhibitors, their adverse effects are inevitable. In the present study, an in silico drug repositioning combined with experimental validation was performed to search for novel potent tyrosinase inhibitors. Docking-based virtual screening results revealed that, among the 3210 FDA-approved drugs available in the ZINC database, amphotericin B, an antifungal drug exhibited the highest binding efficiency against human tyrosinase. Results from tyrosinase inhibition assay demonstrated that amphotericin B could inhibit the activity of mushroom and cellular tyrosinases, especially from MNT-1 human melanoma cells. Molecular modeling results revealed that amphotericin B/human tyrosinase complex exhibited high stability in an aqueous environment. Melanin assay results demonstrated that amphotericin B significantly suppressed melanin production in α-MSH-induced B16F10 murine melanoma and MNT-1 human melanoma cell lines better than the known inhibitor, kojic acid. Mechanistically, amphotericin B treatment significantly activated ERK and Akt signaling pathways, resulting in the decreased expression of MITF and tyrosinase. The obtained results may pursue pre-clinical and clinical studies to examine the possibility of using amphotericin B as an alternative treatment for hyperpigmentation disorders.

Clinical evaluation of a topical Unani pharmacopoeial formulation Tila-e-Kalf in the management of melasma (Kalf): A randomized controlled clinical trial

Objective

Melasma is a chronic, acquired, symmetrical hyper melanosis of skin, characterized by irregular light to dark brown patches on sun-exposed areas, with a significant effect on psychological health; melasma is termed as Kalf in Unani medicine. Conventional treatments have transitory results and often carry adverse effects like skin irritation, scarring, etc. This study was planned to evaluate the safety and efficacy of a Unani pharmacopoeial formulation Tila-e-Kalf, comprising of lentil (Lens culinaris), bitter almond (Prunus amygdalus), and fig (Ficus carica), and to compare its efficacy with standard drug hydroquinone in patients of melasma.

Materials and Methods

This was an 8-week open-label, standard controlled, randomized clinical study conducted on patients of epidermal melasma. The test group received Tila-e-Kalf while the control group received hydroquinone 4% cream for local application once daily. Efficacy was assessed by MASI (Melasma Area Severity Index), DLQI (Dermatology Life Quality Index), and PGA (Physician Global Assessment) and colored photographs.

Results

Mean MASI score decreased from10.65±0.85 to 7.07±0.74 in the test group (p<0.0001) and from 11.28±1.24 to 7.76±0.9 (p<0.0001) the in control group. Similar improvement was noticed in other parameters also. A large number of patients in the control group reported mild burning, itching, dryness, and skin rashes, while only one patient in the test group reported mild itching.

Conclusion

Tila-e-Kalf as a topical depigmenting agent was found equally effective with better tolerability and safety as compared to hydroquinone.

Targeting Tyrosinase in Hyperpigmentation: Current Status, Limitations and Future Promises

Hyperpigmentation is a common and distressing dermatologic condition. Since tyrosinase (TYR) plays an essential role in melanogenesis, its inhibition is considered a logical approach along with other therapeutic methods to prevent the accumulation of melanin in the skin. Thus, TYR inhibitors are a tempting target as the medicinal and cosmetic active agents of hyperpigmentation disorder. Among TYR inhibitors, hydroquinone is a traditional lightening agent that is commonly used in clinical practice. However, despite good efficacy, prolonged use of hydroquinone is associated with side effects. To overcome these shortcomings, new approaches in targeting TYR and treating hyperpigmentation are desperately requiredessentialneeded. In line with this purpose, several non-hydroquinone lightening agents have been developed and suggested as hydroquinone alternatives. In addition to traditional approaches, nanomedicine and nanotheranostic platforms have been recently proposed in the treatment of hyperpigmentation. In this review, we discuss the available strategies for the management of hyperpigmentation with a focus on TYR inhibition. In addition, alternative treatment options to hydroquinone are discussed. Finally, we present nano-based strategies to improve the therapeutic effect of drugs prescribed to patients with skin disorders.

Daphne odora Exerts Depigmenting Effects via Inhibiting CREB/MITF and Activating AKT/ERK-Signaling Pathways

Daphne odora, a blooming shrub, has been traditionally used for various medicinal purposes. However, information on its anti-melanogenic activity and dermal application is limited. In this study, the Daphne odora extract (DOE), with constituents including daphnetin, was used to investigate depigmenting activity and the underlying mechanism of Daphne odora. DOE inhibited in vitro and cellular tyrosinase activity in a dose-dependent manner, and reduced the α-MSH-induced melanin biosynthesis to a control level. The protein expressions of melanin synthesis-related enzymes were also significantly reduced by DOE. Moreover, DOE decreased the phosphorylation of cAMP-response element binding proteins (CREBs) induced by α-MSH in B16F10 cells, while it activated phosphorylated extra-cellular signal-regulated kinases (ERKs) and protein kinase B (AKT) expression. These results suggest that DOE might inhibit the melanogenesis signaling pathways by activating ERK- and AKT-signaling pathways to regulate the expression of CREB and MITF and its downstream pathways. Therefore, DOE could potentially be developed as a depigmenting agent.

Bridging the Gaps between Plant and Human Health: A Systematic Review of Soyasaponins

Saponins, prominent secondary plant metabolites, are recognized for their roles in plant defense and medicinal benefits. Soyasaponins, commonly derived from legumes, are a class of triterpenoid saponins that demonstrate significant potential for plant and human health applications. Previous research and reviews largely emphasize human health effects of soyasaponins. However, the biological effects of soyasaponins and their implications for plants in the context of human health have not been well-discussed. This review provides comprehensive discussions on the biological roles of soyasaponins in plant defense and rhizosphere microbial interactions; biosynthetic regulation and compound production; immunological effects and potential for therapeutics; and soyasaponin acquisition attributed to processing effects, bioavailability, and biotransformation processes based on recent soyasaponin research. Given the multifaceted biological effects elicited by soyasaponins, further research warrants an integrated approach to understand molecular mechanisms of regulations in their production as well as their applications in plant and human health.

Antioxidant Compounds, Kirenol and Methyl ent-16α, 17-dihydroxy-kauran-19-oate Bioactivity-Guided Isolated from Siegesbeckia glabrescens Attenuates MITF-Mediated Melanogenesis via Inhibition of Intracellular ROS Production

Siegesbeckia glabrescens (Compositae), an annual herb indigenous to Korean mountainous regions and has been eaten as a food in Korea. This study investigated ABTS, DPPH and nitric oxide (NO) radical-scavenging activities, and melanin production and TYR inhibitory effects-guided fractionation to identify therapeutic phytochemicals from S. glabrescens that can attenuate oxidation and melanogenesis in murine melanoma B16F10 cells. Nine compounds with inhibitory effects on melanin production, and TYR activity, and ABTS, DPPH, and NO radical scavenging activity were isolated from the 100% ethanol fraction from S. glabrescens. Among the nine compounds, kirenol (K), methyl ent-16α, 17-dihydroxy-kauran-19-oate (MDK) had strong inhibitory effects on melanin production and TYR activity with antioxidant effects. Western blot analysis revealed that K and MDK suppressed tyrosinase-related protein (TYRP)-1, TYRP-2 and microphthalmia-associated transcription factor (MITF) expression. Moreover, these two compounds inhibited intracellular reactive oxygen species (ROS) level in tert-butyl hydroperoxide (t-BHP)-treated B16F10 cells. Our results suggest that S. glabrescens containing active compounds such as K and MDK, which has antioxidant and antimelanogenesis effects, is the potent therapeutic and functional material for the prevention of oxidation-induced hyperpigmentation.

α-Mangostin suppressed melanogenesis in B16F10 murine melanoma cells through GSK3β and ERK signaling pathway

Mangosteen (Garcinia mangostana L) fruit contains many xanthones in its pericarp, such as α-mangostin. Here, we aimed to elucidate the physiological effect of α-mangostin and the mechanism on melanogenesis in mouse B16F10 cells. The melanin production in B16F10 cells was decreased by α-mangostin treatment. α-Mangostin also suppressed the enzymatic activity of tyrosinase, the critical enzyme for melanin synthesis. Furthermore, Western blot analysis revealed that α-mangostin down-regulated the protein quantity of tyrosinase, tyrosinase relative protein (TRP)-2, and microphthalmia-associated transcription factor (MITF). We also used inhibitors of the extracellular signal-regulated kinase (ERK), and glycogen synthase kinase 3 (GSK-3β) to identify the upstream signaling cascade of MITF. Results showed us GSK3β plays a more important role in α-mangostin regulated melanogenesis. Further, the de-pigmentation effect on normal human epidermal melanocytes (NHEMs) of α-mangostin was also confirmed. These results suggested that α-mangostin is a reagent for depigmentation and it has the potential to be applied as a component of cosmetics or pharmaceuticals for the therapy of spots, chloasma, or melanosis.

α-Mangostin suppressed the melanin production in B16F10 cells.

α-Mangostin suppressed the activity of tyrosinase.

α-Mangostin suppressed the protein expression of tyrosinase, TRP-2 and MITF.

GSK3β is involved in α-mangostin-regulated melanogenesis.

α-Mangostin suppressed the melanin production in normal human melanocytes.

Natural skin-whitening compounds for the treatment of melanogenesis (Review)

Melanogenesis is the process for the production of melanin, which is the primary cause of human skin pigmentation. Skin-whitening agents are commercially available for those who wish to have a lighter skin complexions. To date, although numerous natural compounds have been proposed to alleviate hyperpigmentation, insufficient attention has been focused on potential natural skin-whitening agents and their mechanism of action from the perspective of compound classification. In the present article, the synthetic process of melanogenesis and associated core signaling pathways are summarized. An overview of the list of natural skin-lightening agents, along with their compound classifications, is also presented, where their efficacy based on their respective mechanisms of action on melanogenesis is discussed.

p-Hydroxybenzoic Acid β-d-Glucosyl Ester and Cimidahurinine with Antimelanogenesis and Antioxidant Effects from Pyracantha angustifolia via Bioactivity-Guided Fractionation

This study evaluated bioactivity-guided fractionation as a means to identify therapeutic phytochemicals from Pyracantha angustifolia that can attenuate melanogenesis and oxidation. Seven compounds with inhibitory effects on melanin production and tyrosinase (TYR) activity, and ABTS and DPPH radical-scavenging activities, which have not been reported as whitening materials, were isolated from the n-butanol fraction from P. angustifolia leaves (PAL). Among the seven compounds, p-hydroxybenzoic acid β-d-glucosylester (HG), and cimidahurinine (CH) had strong inhibitory effects on melanin production and TYR activity, as well as ABTS and DPPH radical-scavenging activities. Western blot analysis showed that HG and CH suppressed tyrosinase-related protein (TYRP)-1 and TYRP-2 expression. Moreover, HG and CH inhibited reactive oxygen species (ROS) generation in tert-butyl hydroperoxide (t-BHP)-treated B16F10 cells. These results suggest that P. angustifolia containing active compounds, such as HG and CH, is a potent therapeutic candidate for the development of hypopigmenting agents.

Reinvestigation of Herniaria glabra L. saponins and their biological activity

Twelve undescribed triterpenoid pentacyclic glycosides, medicagenic acid (3-O-β-D-glucuronopyranosyl-28-O-{[β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)]-[α-L-rhamnopyranosyl-(1 → 3)]-4-O-acetyl-β-D-fucopyranosyl-(1→)}-2β,3β-dihydroxyolean-12-ene-23,28-dioic acid, 3-O-β-D-glucuronopyranosyl-28-O-{[α-L-rhamnopyranosyl-(1 → 2)]-[β-D-apiofuranosyl-(1 → 3)]-4-O-acetyl-β-D-fucopyranosyl-(1→)}-2β,3β-dihydroxyolean-12-ene-23,28-dioic acid, 3-O-β-D-glucuronopyranosyl-28-O-{[α-L-rhamnopyranosyl-(1 → 2)]-3,4-O-diacetyl-β-D-fucopyranosyl-(1→)}-2β,3β-dihydroxyolean-12-ene-23,28-dioic acid, 28-O-{[6-O-acetyl-β-D-glucopyranosyl-(1 → 2)]-[2-O-acetyl-α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranosyl-(1→)}-2β,3β-dihydroxyolean-12-ene-23,28-dioic acid, 28-O-{[6-O-acetyl-β-D-glucopyranosyl-(1 → 2)]-[3-O-acetyl-α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranosyl-(1→)}-2β,3β-dihydroxyolean-12-ene-23,28-dioic acid, 28-O-{[6-O-acetyl-β-D-glucopyranosyl-(1 → 2)]-[4-O-acetyl-α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranosyl-(1→)}-2β,3β-dihydroxyolean-12-ene-23,28-dioic acid, 28-O-{[6-O-acetyl-β-D-glucopyranosyl-(1 → 2)]-[β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranosyl-(1→)}-2β,3β-dihydroxyolean-12-ene-23,28-dioic acid, 28-O-{[β-D-glucopyranosyl-(1 → 2)]-[β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranosyl-(1→)}-2β,3β-dihydroxyolean-12-ene-23,28-dioic acid), zanhic acid (3-O-β-D-glucuronopyranosyl-28-O-{[β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)]-[α-L-rhamnopyranosyl-(1 → 3)]-4-O-acetyl-β-D-fucopyranosyl-(1→)}2β,3β,16α-trihydroxyolean-12-ene-23,28-dioic acid, 3-O-β-D-glucuronopyranosyl-28-O-{[β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)]-β-D-fucopyranosyl-(1→)}-2β,3β,16α-trihydroxyolean-12-ene-23,28-dioic acid), 29-hydroxy-medicagenic acid (3-O-β-D-glucuronopyranosyl-28-O-{[β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)]-[α-L-rhamnopyranosyl-(1 → 3)]-4-O-acetyl-β-D-fucopyranosyl-(1→)}-2β,3β,29β-trihydroxyolean-12-ene-23,28-dioic acid) and herniaric acid (28-O-{[6-O-acetyl-β-D-glucopyranosyl-(1 → 2)]-[α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranosyl-(1→)}-2β,3β-dihydroxyolean-18-ene-23,28-dioic acid) were isolated from the whole plant extract of Herniaria glabra L. (Caryophyllaceae), wild growing in the Ukraine. In addition, five known triterpenoid saponins; i.e. herniariasaponins 1, 4, 5, 6, and 7 were also isolated. Their structures were elucidated by HRESIMS, 1D and 2D NMR spectroscopy, as well as by comparison with the literature data. Twelve herniariasaponins, the purified crude extract, and the saponin fraction were evaluated in vitro for their xanthine oxidase, collagenase, elastase, and tyrosinase inhibitory activity. Moreover, herniariasaponins 4, 5, and 7 were screened for their cholinesterase inhibitory potential. As a result, no or low inhibition towards the mentioned enzymes was observed.

Phlorotannins with Potential Anti-tyrosinase and Antioxidant Activity Isolated from the Marine Seaweed Ecklonia stolonifera

Compounds were isolated from Ecklonia stolonifera Okamura, a marine brown alga widely consumed as food. Among the isolated compounds, 974-A was demonstrated for the first time to be a potent competitive inhibitor of mushroom tyrosinase activity towards l-tyrosine and l-DOPA (IC₅₀ values = 1.57 ± 0.08 and 3.56 ± 0.22 µM, respectively). Molecular docking simulations clarified that the hydroxyl residues of the isolated compounds formed hydrogen bonds with residues at the catalytic and allosteric sites of tyrosinase, while other residues participated in hydrophobic interactions. Moreover, 974-A, phlorofucofuroeckol-A and eckol reduced the cellular melanin content and tyrosinase activity, and downregulated the expression of melanogenesis enzymes including tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2 in B16F10 melanoma cells. These compounds also effectively scavenged radicals at the cellular level. Thus, our results revealed that compounds isolated from E. stolonifera are potent tyrosinase inhibitors with potential applications in the cosmetic industry for treatment of hyperpigmentation and for the anti-browning effect in the agricultural field.

Effect of lidocaine on the safety of postoperative skin reconstruction after malignant melanoma resection

Malignant melanoma is a type of skin cancer with high morbidity and mortality. Therapeutic strategies should be individualized in order to increase the survival rate. The aim of this study was to assess the effect of lidocaine on skin healing and immune function after operation of patients with melanoma. Sixty patients with melanoma were selected from those treated in Bishan Hospital between August 2014 and August 2016. The patients were randomly divided into lidocaine group and control group. Lidocaine group was locally treated with an intradermic injection of 2% lidocaine solution in dose of 1.5 mg/kg and the control group received the same quantity of saline solution. In the lidocaine group, the rates of skin temperature, drug reaction, healing and infection were higher than the corresponding rates in the C group. The local application of lidocaine can promote wound healing to a certain extent, reduce pain, and promote postoperative skin reconstruction.

Comparison of biofunctional activity of Asparagus cochinchinensis (Lour.) Merr. Extract before and after fermentation with Aspergillus oryzae

Asparagus cochinchinensis root (ACR) is used in traditional Chinese medicine. In this study, ACR was first extracted with 25% ethyl acetate (EA) and then fermented by Aspergillus oryzae to enhance its antioxidant activity and evaluate its potential antityrosinase activity. The physiological activity and cytotoxicity of A. oryzae-fermented ACR extract, along with its antityrosinase activity and effects on melanogenic factor levels in human epidermal melanocytes (HEMs), were analyzed and compared with those of the unfermented extract. The results showed that the physiological activity of the fermented extract in vitro or in cells was significantly higher than that of the unfermented extract. The IC₅₀ values for 2,2-diphenyl-1-picrylhydrazine radical scavenging activity, reducing power, and antityrosinase activity in vitro for the fermented extract were 250.6 ± 32.5, 25.7 ± 3.5, and 50.6 ± 3.1 mg/L, respectively. The fermented extract favored cellular antityrosinase activity with low melanin production in human melanoma cells compared with the unfermented extract. The inhibitory mechanism of melanin synthesis by unfermented extract was independent of the tested melanogenesis-related proteins. However, the inhibitory mechanism of the fermented extract was possibly caused by synergistic inhibition of these proteins. Thus, A. oryzae-fermented ACR extract may be used for developing new health food or cosmetic ingredients.

A preliminary study of growth characteristics of melanocytes co-cultured with keratinocytes in vitro

To clarify the characteristic growth of melanocytes (MCs) and Keratinocytes (KCs) in vitro and discuss the mechanism of culturing autologous melanocytes in the treatment of vitiligo. Epidermis cells derived from normal skin tissues were isolated and cultured in vitro. Melanocytes in DOPA staining were observed. The expression level of markers in MCs was detected by qRT-PCR and the percentage of MCs and KCs were detected by flow cytometry. Cells derived from normal skin tissues mainly included KCs, MCs, and fibroblasts. There were significant differences between the percentage of KC, MC, fibroblasts (P < 0.05), and the expression of Microphthalmia-associated transcription factor (P < 0.05) and Tyrosinase-related protein-2 (P < 0.05) in the second, 10th, 20th, and 30th day. Significant differences were also found between the average numbers of MC stained by DOPA (P < 0.05) and the average percentage of MCs in the 10th, 20th, and 30th Day (P < 0.05). But there were no significant differences between the average percentage of KCs in the 10th, 20th, and 30th Day (P > 0.05) detected by flow cytometry. The number of MCs co-cultured with KCs in vitro reached the maximum in the 20th Day and this co-cultured model may contribute to the growth of MCs which could be used in the treatment of vitiligo.