Nicotinamide adenine dinucleotide (NAD⁺) is indispensable for the regulation of biological metabolism. Previous studies have revealed its role in aging and degenerative diseases, while crucially showing that supplementation with NAD⁺ or its precursors could ameliorate or reverse the progression of aging. Despite extensive evidence for the role and action of NAD⁺ in aging, its pharmacological activity on the skin, or even its mechanism, has not been elucidated. In this study, we established a novel approach to effectively utilize NAD⁺ for skin anti-aging by enhancing the pharmacological efficacy of exogenous NAD⁺ using a phytochemical complex consisting of quercetin, and enoxolone through inhibition of CD38. Through the comprehensive in vitro experiments based on human fibroblasts, we observed that exogenous NAD⁺ could exert protective effects against both extrinsic aging induced by ultraviolet light exposure and intrinsic aging. Additionally, we found that its effects were significantly boosted by quercetin and enoxolone. In this in-depth study, we demonstrated that these beneficial effects are mediated by improved sirtuin activation, autophagy, and mitochondrial functionality. Our approach is expected to verify the applicability of the topical application of NAD⁺ and offer more effective solutions for the unmet needs of patients and consumers who demand more effective anti-aging effects.

Hydroxyethyl cellulose (HEC), widely known for its biocompatibility and water solubility, is a polysaccharide with potential for pharmaceutical applications. Here, we synthesized polyethylenimine2k (PEI2k)-conjugated hydroxyethyl cellulose (HECP2k) for doxorubicin/Bcl-2 siRNA co-delivery systems. HECP2ks were synthesized by reductive amination of PEI2k with periodate-oxidized HEC. The synthesis of the polymers was characterized using ¹H NMR, ¹³C NMR, primary amine quantification, FT-IR, and GPC. Via agarose gel electrophoresis and Zeta-sizer measurement, it was found that HECP2ks condensed pDNA to positively charged and nano-sized complexes (100–300 nm, ~30 mV). The cytotoxicity of HECP2ks was low and HECP2k 10X exhibited higher transfection efficiency than PEI25k even in serum condition, showing its high serum stability from ethylene oxide side chains. Flow cytometry analysis and confocal laser microscopy observation verified the superior cellular uptake and efficient endosome escape of HECP2k 10X. HECP2k 10X also could load Dox and Bcl-2 siRNA, forming nano-particles (HECP2k 10X@Dox/siRNA). By median effect analysis and annexin V staining analysis, it was found that HECP2k 10X@Dox/siRNA complexes could cause synergistically enhanced anti-cancer effects to cancer cells via induction of apoptosis. Consequently, it was concluded that HECP2k possesses great potential as a promising Dox/Bcl-2 siRNA co-delivery carrier.

Background/Objectives: Enhancement of cellular NAD⁺ mediated by NMN has emerged as a pivotal strategy in modulating the aging process. This study aimed to systematically investigate the anti-aging effects of NMN on human skin fibroblasts, focusing on how the former contributes to the improvement of cellular health and function. This study elucidated the molecular and functional mechanisms by which NMN contributes to the attenuation of skin aging. Methods: We performed extensive in vitro and transcriptomic analyses. Human skin fibroblasts were treated with NMN, and the induced biological responses were observed under oxidative stress/photo-aging models. Results: Transcriptome analysis revealed distinct gene expression patterns for NAD⁺ and its precursors (NMN, NR, and NAM), showing significant differences between NMN and other precursors (NR and NMN). NMN seemed to be significantly involved in cytokine and chemokine activity. It significantly elevated cellular NAD⁺ levels, activated sirtuin and autophagy pathways, and enhanced mitochondrial function, collectively maintaining cellular homeostasis under stress. Furthermore, it suppressed cellular senescence, promoted cell proliferation, supported extracellular matrix integrity, and accelerated wound healing. Conclusions: The study provided essential mechanistic evidence supporting the anti-aging effects of NMN in skin cells and addressed the current lack of scientific validation of NMN-based topical applications. The findings established a solid academic background for future translational research and the development of NMN-based therapeutics and cosmeceuticals.

Nicotinamide adenine dinucleotide (NAD⁺) is a pivotal coenzyme whose decline drives mitochondrial dysfunction and senescence. However, NAD⁺ delivery to skin is limited by poor stability and tissue accessibility. Here, we develop an ion-coupled NAD⁺ transfersome (ICoN) that stabilizes NAD⁺ and enables efficient, non-invasive transdermal delivery. ICoN restores intracellular NAD⁺ levels and reverses transcriptomic programs associated with DNA damage, oxidative stress, and senescence in vitro. Functionally, ICoN promotes mitochondrial functional integrity and sustains proliferative and migratory competence under senescent and NAD⁺-depleted conditions. In ex vivo porcine and human skin explants, ICoN achieves superior intratissue NAD⁺ penetration while attenuating senescent signatures compared with free NAD⁺ or precursors. Integrated high-spatial-resolution transcriptomic profiling and bulk transcriptomic analyses of UV-stressed human skin reveal that ICoN mitigates histological disruption and senescence-associated transcriptional programs at the tissue level. Moreover, ICoN extends lifespan and enhances healthspan in C. elegans. These findings characterize ICoN as a transdermal NAD ⁺ delivery platform supporting localized NAD ⁺ restoration in the context of skin aging.

This study deals with the extraction of active compounds for a formula (Angelica gigas, Cornus officinalis, Ganoderma lucidum, Thymus vulgaris, and Asparagus cochinchinensis) and the evaluation of its skin anti-aging properties. This formulation was inspired by the oriental medicine Gongjin-dan (Angelica gigas, Cornus officinalis, deer antler, and musk), which has been used as a restorative drug for longevity. Enzyme-based extraction and chemical purification were used to obtain a mixed fraction (GEF) enriched in glycopeptides and glycoproteins from the five herbal materials. The chemical characteristics of GEF, including the carbohydrate groups attached to the peptides and proteins, the total carbohydrate and protein contents, and the composition of monosaccharides and amino acids were determined. The chemical characteristics that were significantly different from those of the extract, generally prepared in the same ratio, were the abundance of glycopeptides and glycoproteins and the high proportions of conditionally essential amino acids (51.0%) and acidic/basic amino acids (67.7%). These are necessary components for strengthening the skin layers against aging. The in vitro skin anti-aging properties of GEF on human fibroblasts (HS68), keratinocytes (HaCaT), and adipose-derived mesenchymal stem cells (ADMSCs) were evaluated. It was found that MMP-1 gene expression was inhibited (18–28%) and fibrillin-1 protein (23–37%) was restored contrary to the effect of UV irradiation. COL1A1 and COL4A1 gene expression (25–35%), HAS2 gene expression (22–213%), and adipogenesis (15%) were facilitated. These results demonstrate the potential of GEF as a raw material for skin anti-aging and reinforce the scientific evidence supporting a traditional medicine with a long history.