Benzylamide derivative compound attenuates the ultraviolet B-induced hyperpigmentation in the brownish guinea pig skin

Skin hyperpigmentation and its treatment with herbs: an alternative method

Background

With an increasing number of patients, those who are facing a lot of skin-related complaints, often referred to as skin of pigmentation patients, are on the rise. Among all the most common complaints in patients with skin of color is hyperpigmentation. So, there is need of herbal formulation for treatment of hyperpigmentation.

Main body

This review article addresses the different types of hyperpigmentation, causes, and its treatment with herbs for the management of the skin hyperpigmentation. As uneven pigmentation of skin or hyperpigmentation is a common skin condition, which occurs when the skin produces more melanin. This can make spots or patches of skin appear darker than surrounding areas. Some forms of hyperpigmentation with post-inflammatory, melasma, and sun spots are more likely to affect areas of face, arms, and legs due to sun exposure and injury. Although the availability of multiple treatments for the condition which leads to some adverse effects, hyperpigmentation continues to present skin care management challenges for dermatologists.

Conclusion

Some plants and phytoconstituents, e.g., Azadirachta indica, Glycyrrhiza glabra, Panax ginseng and genistein, ellagic acids, quercetin, are very useful in herbal cosmetic as anti-hyperpigmentry agents in cosmetic industries. Some of flavonoids and triterpenoids present in plants also show their effect as antioxidant and skin whitening agents. It is expected that this review will compile and improve the existing knowledge on the potential utilization of herbs for the treatment of skin hyperpigmentation.

Metabolic Forest: Predicting the Diverse Structures of Drug Metabolites

Adverse drug metabolism often severely impacts patient morbidity and mortality. Unfortunately, drug metabolism experimental assays are costly, inefficient, and slow. Instead, computational modeling could rapidly flag potentially toxic molecules across thousands of candidates in the early stages of drug development. Most metabolism models focus on predicting sites of metabolism (SOMs): the specific substrate atoms targeted by metabolic enzymes. However, SOMs are merely a proxy for metabolic structures: knowledge of an SOM does not explicitly provide the actual metabolite structure. Without an explicit metabolite structure, computational systems cannot evaluate the new molecule's properties. For example, the metabolite's reactivity cannot be automatically predicted, a crucial limitation because reactive drug metabolites are a key driver of adverse drug reactions (ADRs). Additionally, further metabolic events cannot be forecast, even though the metabolic path of the majority of substrates includes two or more sequential steps. To overcome the myopia of the SOM paradigm, this study constructs a well-defined system-termed the metabolic forest-for generating exact metabolite structures. We validate the metabolic forest with the substrate and product structures from a large, chemically diverse, literature-derived dataset of 20 736 records. The metabolic forest finds a pathway linking each substrate and product for 79.42% of these records. By performing a breadth-first search of depth two or three, we improve performance to 88.43 and 88.77%, respectively. The metabolic forest includes a specialized algorithm for producing accurate quinone structures, the most common type of reactive metabolite. To our knowledge, this quinone structure algorithm is the first of its kind, as the diverse mechanisms of quinone formation are difficult to systematically reproduce. We validate the metabolic forest on a previously published dataset of 576 quinone reactions, predicting their structures with a depth three performance of 91.84%. The metabolic forest accurately enumerates metabolite structures, enabling promising new directions such as joint metabolism and reactivity modeling.

Smilax china leaf extracts suppress pro-inflammatory adhesion response in human umbilical vein endothelial cells and proliferation of HeLa cells

Objective: The objective of this study was to investigate the anti-inflammatory and anticancer effects of the leaves of Smilax china.Methodology: The aqueous extract was examined for its anti-inflammatory effects on tumour necrosis factor (TNF)-α-induced inflammation in HUVECs whereas the aqueous (water), ethyl acetate (EA), butanol (B) and methylene chloride (MC) extracts were examined for their anticancer effect on HeLa cells.Results: The aqueous extract suppressed the (TNF)-α-induced expression of ICAM-1, VCAM-1 and TNF-R1 and attenuated the expression of MCP-1, MMP-9, NF-kB and IFN-γ. The MC extract suppressed the proliferation of HeLa cells at all doses employed (50, 150, and 300 µg/ml). The EA extract demonstrated appreciable anti-proliferative effect whereas the BuOH extract demonstrated mild anti-proliferative activity. The aqueous extract did not show any significant anti-proliferative effect. None of the extracts were toxic to the normal cells (HUVECs).Conclusion: Smilax china leaf extracts possess significant anti-inflammatory and anticancer effects.

Melanocytes derived from mouse hair follicles: A novel study model to assess pigmentation disorders

Melanocytes are the major cells responsible for skin and fair pigmentation in vertebrates. They localize to hair follicles(HFs) and the epidermis during embryonic development. A reduced number or dysfunction of melanocytes results in pigmentation disorders.Thus, methods for isolation, culture, and identification of melanocytes in mouse hair follicles provide an experimental basis for thestudy of of pigmentation disorders. In the current work, we harvested the melanocytes from the anagen phase dorsal skin of C57BL/6 mice.After its separation from the skin, the dermis was digested, and the HFs were released. HFs were then also digested, and the cells released from HFs were cultured in melanocyte growth medium. Immunofluorescence and immunohistochemistry staining were used to localize the distribution of melanocytes in HFs . Reverse transcription polymerase chain reaction was performed to detect the expression of specific melanocyte marker genes. Immunofluorescence, immunohistochemistry, flow cytometry, and western blot were carried out to detect the expression of marker proteins in cells. 3,4-Dihydroxy-L-phenylalanine (L-DOPA) staining was used to detect the pigmentation functionality of melaonocytes. Based on our results, we conclude that mature and functional melanocytes can be successfully obtained from theHFs, providing a cell model to study pigmentation disorders. The current findings provide novel insights for the treatment of pigmentation disorders by autologous cell transplantation. Further, we believe that issues related to skin damage, insufficient numbers of autologous cells, and autoimmune problems can be resolved in future though the use of functional melanocytes.

Resveratrol analog, N-(4-methoxyphenyl)-3,5-dimethoxybenzamide induces G2/M phase cell cycle arrest and apoptosis in HeLa human cervical cancer cells

In this study, several resveratrol analogs were synthesized and evaluated in search of a more effective anti-proliferative resveratrol analog. Among the evaluated resveratrol analogs, we have identified N-(4-methoxyphenyl)-3,5-dimethoxybenamide (MPDB) as a potent anti-proliferative compound. Treatment with MPDB resulted in G₂/M phase cell cycle arrest, which was accompanied by alteration of G₂/M-related protein expression and phosphorylation. MPDB-induced G₂/M arrest was blocked by transfection of ATM/ATR siRNAs, indicating the critical role of ATM/ATR in G₂/M phase arrest. In addition, treatment with MPDB displayed the activation of caspase and decreased Bcl-xl protein expression after 20 h in HeLa cells. Moreover, MPDB increased cytosolic cytochrome c release and Fas and Fas-L protein expression, indicating intrinsic and extrinsic apoptosis pathway, respectively. These results suggest that MPDB is a new and potent compound that induces ATM/ATR-dependent G₂/M phase cell cycle arrest and apoptosis, implicating it as a putative candidate in the investment of cervical cancer therapy.

Antimelanogenic chemicals with in vivo efficacy against skin pigmentation in guinea pigs

Ultraviolet (UV) radiation under sunlight stimulates skin pigmentation through immediately affecting the oxidative modification of existing melanin pigments and the spatial redistribution of pigmented melanosomes followed by the up-regulation of melanogenic genes in delayed kinetics. However, abnormal accumulation and synthesis of melanin biopolymers are responsible for skin disorders with more pigmented patches. Chemical-based regulation of the hyperpigmented disorders has been a long-standing goal for cosmetic and pharmaceutical applications. A large number of the chemicals with antimelanogenic activity have met with limited or no success in the treatment of skin patients, since they may not overcome the challenge of penetrating the skin barrier. Guinea pig skin displays similar kinetic parameters to human skin in the transdermal absorption of numerous chemicals, thus can serve as the surrogate for human skin. Here, we provide a concise review of our current understanding of the chemical-based therapy against skin hyperpigmentation in UV-irradiated guinea pig models, suggest molecular mechanisms of the action and emphasize the translation from preclinical outcomes to skin patients.

Whitening effect of black tea water extract on brown Guinea pig skin

To evaluate the whitening effect of black tea water extract (BT), BT was topically applied to artificially hyperpigmented spots on the back skins of brown guinea-pigs (weight: 450~500 g) induced by 1,500 mJ/ cm² of ultraviolet B (UVB) irradiation. The test compounds of 30 μl were applied twice a day, six days a week, for four weeks. The artificially hyperpigmented spots were divided into 5 groups: control (UVB + saline, C), vehicle control [UVB + propylene glycol: ethanol: water (5 : 3 : 2), VC], positive control (UVB + 2% hydroquinone, PC), experimental 1 (UVB + 1% BT), experimental 2 (UVB + 2% BT). After 4-week application, the spots were removed by biopsy punch under anesthetic condition and used as specimens for the histological examination. The total polyphenol and flavonoid contents of BT were 104 and 91 mg/g, respectively. The electron-donating ability of BT revealed a dose-dependent response, showing the excellent capacities of 86% at 800 μg/ml. The artificially hyperpigmented spots treated with the PC and BT were obviously lightened compared to the C and VC groups. At the fourth week, the melanin indices for the PC and BT groups were significantly lower (p < 0.00l) than those of the C and VC groups. In histological examination, PC and BT groups were significantly reduced in the melanin pigmentation, the proliferation of melanocytes and the synthesis of melanosomes compared to the C and VC groups. It is found that BT inhibits the proliferation of melanocytes and synthesis of melanosomes in vivo using brown guinea pigs, thereby showing a definite skin whitening effect.

Inhibitory effects of Cyrtomium fortunei J. Smith root extract on melanogenesis

Background:

Recently, a great deal of attention has been directed toward the use of crude extracts from natural products for cosmetic applications. Thus, we performed a series of experiments to investigate skin depigmenting properties of a crude extract that was derived from a traditional Korean medicinal plant.

Materials and Methods:

In this study, the depigmentational potency of Cyrtomium fortunei J. Smith was investigated. The inhibitory effects of the root of Cyrtomium fortunei J. Smith extract on melanin production were evaluated by assessing its tyrosinase inhibitory effects, melanin production-inhibitory properties in melan-a cells and depigmenting ability in brown guinea pig skin.

Results:

The methanolic extract of the root of Cyrtomium fortunei J. Smith appeared to inhibit tyrosinase activity and melanin production in melan-a cells. In addition, this extract exhibited depigmenting ability on Ultra violet-induced hyper pigmentation in brown guinea pig skin.

Conclusion:

These results suggested that root of Cyrtomium fortunei J. Smith might prove useful in treating skin hyperpigmentation associated with excess sun-exposure.

Inhibitory effects of cinnamic acid on melanin biosynthesis in skin

Cinnamic acid is a wildly distributed phenylpropanoid component naturally occurring in plants, and is mainly found in Cinnamomum cassia BLUME and Panax ginseng. Cinnamic acid was recently reported to exert a tyrosinase inhibitory effect. However, research on melanocytes and animal bodies was not reported until now. In this study, we examined the effects of cinnamic acid on melanin biosynthesis within the melanocytes and brown guinea pigs. Melan-a cells were used to examine the effects of cinnamic acid in the melanocytes. Treatment with 100 ppm of cinnamic acid resulted in a significant reduction of melanin production in the melan-a cells at 29.0%. This compound also exhibited a potent inhibitory effect on tyrosinase activity and reduced tyrosinase expression in the melan-a cells. Moreover, cinnamic acid exhibited depigmenting activity on the UV-B-induced hyperpigmentation of brown guinea pig skin. Our results suggest that cinnamic acid might act as a skin whitening agent via inhibition of tyrosinase activity and expression within melanocytes.

Synthesis, discovery and mechanism of 2,6-dimethoxy-N-(4-methoxyphenyl)benzamide as potent depigmenting agent in the skin

In this study, a new skin-depigmenting agent, 2,6-dimethoxy-N-(4-methoxyphenyl)benzamide (DMPB), was synthesized using a combination of benzoic acid and aniline. DMPB exhibited significant depigmentation ability on the UV B-induced hyperpigmentation of the brown guinea pig skin. In addition, the 100ppm treatment with this compound had a 30% inhibitory effect on melanin pigment generation in the melan-a cell line without significant cell toxicity. To search for relationship with the depigmentation, the effects of DMPB on the tyrosinase and dopachrome tautomerase were evaluated. DMPB had no effect on tyrosinase. However, it accelerated dopachrome transformation into 5,6-dihydroxyindole-2-carboxylic acid (DHICA) in the presence of dopachrome tautormerase. In addition, intracellular level of dopachrome tautomerase in melan-a cells was increased by treatment of DMPB. These results suggest that the pigment-lightening effects of DMPB might be due to biased production of DHICA-eumelanin induced by dopachrome tautormerase activation.

Potent inhibitory effects of N-aryl S-alkylthiocarbamate derivatives on the dopa oxidase activity of mushroom tyrosinase

This study reports the potent inhibitory effect of N-aryl S-alkylthiocarbamate derivatives on mushroom tyrosinase (MT) activity. N-Aryl S-alkylthiocarbamate derivatives were found to exhibit a potent inhibitory effect on the dopa (3,4-dihydroxyphenylalanine) oxidase activity of mushroom tyrosinase. Most of the N-aryl S-alkylthiocarbamate derivatives (compounds from A to J) exhibited higher inhibitory effects than kojic acid (IC50=318 microM), a well known tyrosinase inhibitor. Tyrosinase was the most inhibited by S-phenetyl N-phenylthiocarbamate (compound E, IC50=7.25 microM), and this inhibition was 44 times stronger than that of kojic acid. Compound E exhibited 95.0% of inhibition at 100 microM. A kinetic study of MT inhibition by compound E using the Lineweaver-Burk plots analysis was performed. And the kinetics profiles observed suggest that compound E competitively inhibits MT.