Syringaresinol Inhibits UVA-Induced MMP-1 Expression by Suppression of MAPK/AP-1 Signaling in HaCaT Keratinocytes and Human Dermal Fibroblasts.

Ultraviolet (UV) irradiation induces detrimental changes in human skin which result in photoaging. UV-induced intracellular changes cause degradation of extracellular matrix (ECM). UV-stimulated cleavage of collagen in ECM occurs via matrix metalloproteinases (MMPs).

Development and evaluation of topical formulations for a novel skin whitening agent (AP736) using Hansen solubility parameters and PEG-PCL polymers.

AP736 itself is a novel skin whitening agent reported to exhibit anti-melanogenic and tyrosinase inhibitory activity. However, formulating a topical product has been difficult because AP736 is insoluble in water as well as in many oils. In this study, we aimed to develop a new topical delivery system in which AP736 is not only physically stable, but also suitably delivered to the skin.

Antimelanogenic activity of a novel adamantyl benzylbenzamide derivative, AP736: a randomized, double-blind, vehicle-controlled comparative clinical trial performed in patients with hyperpigmentation during the summer.

Background/purpose: AP736 is a novel compound with an adamantyl benzylbenzamide moiety that has shown antimelanogenic activity in melanocytes in vitro and in artificial skin equivalent through the inhibition of key melanogenic enzymes and suppression of the cAMP-phosphokinase A-cAMP response element-binding protein signaling pathway. To estimate the clinical effectiveness of AP736 for the treatment of facial hyperpigmentation, we examined the efficacy and safety of a topical formulation containing AP736 compared with a vehicle formulation in human facial skin. To evaluate the degree of whitening when used in a real-life situation, subjects with hyperpigmentation conditions were selected and the trial was performed from mid-May to the end of June, when there are strong UV rays in Korea.

Different effects of five depigmentary compounds, rhododendrol, raspberry ketone, monobenzone, rucinol and AP736 on melanogenesis and viability of human epidermal melanocytes.

Numerous medications are used to treat hyperpigmentation. However, several reports have indicated that repeated application of some agents, such as rhododendrol (RD), raspberry ketone (RK) and monobenzone (MB), can be toxic to melanocytes. Although these agents had severe side effects in human trials, no current in vitro methods can predict the safety of such drugs.

NF-κB/AP-1-targeted inhibition of macrophage-mediated inflammatory responses by depigmenting compound AP736 derived from natural 1,3-diphenylpropane skeleton.

AP736 was identified as an antimelanogenic drug that can be used for the prevention of melasma, freckles, and dark spots in skin by acting as a suppressor of melanin synthesis and tyrosinase expression. Since macrophage-mediated inflammatory responses are critical for skin health, here we investigated the potential anti-inflammatory activity of AP736. The effects of AP736 on various inflammatory events such as nitric oxide (NO)/prostaglandin (PG) E2 production, inflammatory gene expression, phagocytic uptake, and morphological changes were examined in RAW264.

Novel inhibitory effect of N-(2-hydroxycyclohexyl)valiolamine on melanin production in a human skin model.

Hyper-pigmentation causes skin darkness and medical disorders, such as post-inflammatory melanoderma and melasma. Therefore, the development of anti-melanogenic agents is important for treating these conditions and for cosmetic production. In our previous paper, we demonstrated that the anti-diabetic drug voglibose, a valiolamine derivative, is a potent anti-melanogenic agent.

Synthesis and structure-activity relationship of cyclopentenone oximes as novel inhibitors of the production of tumor necrosis factor-α.

3-Alkyl-2-aryl-2-cyclopenten-1-one oxime derivatives (1) were studied as a novel class of inhibitors of tumor necrosis factor α (TNF-α) with regard to synthesis and in vitro SAR inhibition of TNF-α. The in vitro IC50 values of these compounds in rat and human peripheral blood mononuclear cells were at the sub-micromolar level.

3D-QSAR study of adamantyl N-benzylbenzamides as melanogenesis inhibitors.

Three-dimensional quantitative structure-activity relationship (3D-QSAR) modeling, comparative molecular field analysis (CoMFA), and comparative molecular similarity indices analysis (CoMSIA) of polyhydroxylated N-benzylbenzamide derivatives containing an adamantyl moiety were performed to understand the mechanism of action and structure-activity relationship of these compounds. Contour map analysis indicated that steric contributions of the adamantyl moiety and electrostatic contributions of the hydroxyl group at the 3-position are important in the activity. Activities of the training set and test sets predicted by CoMFA fit well with actual activities, demonstrating that CoMFA, along with the best calculated q(2) value, has the best predictive ability.

A novel adamantyl benzylbenzamide derivative, AP736, suppresses melanogenesis through the inhibition of cAMP-PKA-CREB-activated microphthalmia-associated transcription factor and tyrosinase expression.

Melanogenesis is essential for the protection of skin against UV, but excessive production of melanin causes unaesthetic hyperpigmentation. Much effort is being made to develop effective depigmenting agents. Here, we found that a tyrosinase inhibitor, AP736 (5-adamantan-1-yl-N-(2,4-dihydroxy-benzyl)-2,4-dimethoxy-benzamide) potently suppresses tyrosinase expression, and the mechanism underlying was elucidated.

Depigmenting activities of kojic acid derivatives without tyrosinase inhibitory activities.

We synthesized benzoate ester derivatives of kojic acid with and without adamantane moiety. Benzoate derivatives 2a-e that did not contain an adamantane moiety showed potent tyrosinase inhibitory activities. However, depigmenting activity was not noted in a cell-based assay.

Adamantyl N-benzylbenzamide: new series of depigmentation agents with tyrosinase inhibitory activity.

A new series of polyhydroxylated N-benzylbenzamide derivatives containing an adamantyl moiety has been synthesized, and the depigmenting and tyrosinase inhibitory activities of the molecules were evaluated. The lipophilic character of the adamantyl moiety appeared to confer greater depigmentation power on the benzamide derivatives as compared to those lacking adamantyl substitution. Molecular modeling was applied in order to elucidate the interactions between ligands and tyrosinase that led to inhibition.

Inhibitory activity of novel kojic acid derivative containing trolox moiety on melanogenesis.

A novel kojic acid derivative containing a trolox moiety, (±)-5-hydroxy-4-oxo-4H-pyran-2-yl methyl 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylate (3a), was synthesized. The two biologically active compounds, namely, kojic acid and trolox, were conjugated via an ester bond as they are expected to behave synergistically. The antioxidant activity and the tyrosinase inhibitory activity of this novel kojic acid derivative on melanogenesis were evaluated.

Novel potent antagonists of transient receptor potential channel, vanilloid subfamily member 1: structure-activity relationship of 1,3-diarylalkyl thioureas possessing new vanilloid equivalents.

Recently, 1,3-diarylalkyl thioureas have merged as one of the promising nonvanilloid TRPV1 antagonists possessing excellent therapeutic potential in pain regulation. In this paper, the full structure-activity relationship for TRPV1 antagonism of a novel series of 1,3-diarylalky thioureas is reported. Exploration of the structure-activity relationship, by systemically modulating three essential pharmacophoric regions, led to six examples of 1,3-dibenzyl thioureas, which exhibit Ca(2+) uptake inhibition in rat DRG neuron with IC(50) between 10 and 100 nM.

Biarylcarboxybenzamide derivatives as potent vanilloid receptor (VR1) antagonistic ligands.

Seventeen biarylcarboxybenzamide derivatives were prepared for the study of their agonistic/antagonistic activities to the vanilloid receptor (VR1) in rat DRG neurons. The replacement of the piperazine moiety of the lead compound 1 with phenyl ring showed quite enhanced antagonistic activity. Among the prepared derivatives, N-(4-tert-butylphenyl)-4-pyridine-2-yl-benzamide (2, IC(50)=31 nM) and N-(4-tert-butylphenyl)-4-(3-methylpyridine-2-yl)benzamide (3g, IC(50)=31 nM), showed 5-fold higher antagonistic activity than 1 in (45)Ca(2+)-influx assay.

2,3-diarylpyran-4-ones: a new series of selective cyclooxygenase-2 inhibitors.

A new series of cyclooxygenase-2 (COX-2) inhibitors with gamma-pyrone as central scaffold unit has been synthesized and their biological activities were evaluated against cyclooxygenase inhibitory activity. The changes of physical properties of the molecules were performed according to the medicinal chemistry principles and moderate oral anti-inflammatory activity was obtained with this series of inhibitors.

Chain-branched 1,3-dibenzylthioureas as vanilloid receptor 1 antagonists.

A series of chain-branched 1,3-dibenzylthiourea derivatives were synthesized, and tested their antagonist activity against vanilloid receptor 1. Chain-branching led to a significant change in the mode of action and the potency. (R)-Methyl or ethyl-branched 1,3-dibenzylthiourea derivatives showed the most potent antagonist activity up to the IC(50) value of 0.

N-4-methansulfonamidobenzyl-N'-2-substituted-4-tert-butyl-benzyl thioureas as potent vanilloid receptor antagonistic ligands.

A series of N-4-methansulfonamidobenzyl-N'-2-substituted-4-tert-butylbenzyl thioureas were prepared for the study of their agonistic/antagonistic activities to the vanilloid receptor in rat DRG neurons. Their structure-activity relationship reveals that there is a space for another hydrophobic binding interaction around 2-position in 4-tert-butylbenzyl region. Among the prepared derivatives, 6n show the highest antagonistic activity against the vanilloid receptor (IC(50)=15 nM).

Novel non-vanilloid VR1 antagonist of high analgesic effects and its structural requirement for VR1 antagonistic effects.

A novel non-vanilloid VR1 antagonist consisting of a new vanilloid equivalent exhibits excellent analgesic effects as well as highly potent antagonistic activities in both capsaicin single channel and calcium uptake assays. In addition, the structural requirement for the vanilloid equivalent of the potent VR1 antagonist has also been elucidated.

A facile one-pot synthesis of 4,5-diaryl-2,2-dimethyl-3(2H)-furanones.

An efficient and practical one-pot synthesis of 4,5-diaryl-2,2-dimethyl-3(2H)-furanones has been achieved from 1,2-diarylethanones and 2-bromoisobutyryl cyanide in the presence of excess base, by employing the 'hard soft acid base' principle. The reaction scope of 2-bromoisobutyryl cyanide could be expanded to prepare a variety of 2,2-dimethyl-3(2H)-furanone derivatives other than 4,5-diaryl-2,2-dimethyl-3(2H)-furanones.