Ruixuan Geng

Background: Skin photoaging is primarily caused by prolonged ultraviolet (UV) exposure, which manifests as dryness and wrinkle formation. Recent studies highlight that beneficial microorganisms have garnered considerable attention for their emerging role in modulating host health, especially in skin photoaging. Methods: To investigate the role of two strains, Bifidobacterium animalis subsp. lactis BL-G101 (BL-G101) and Lactobacillus acidophilus LA-G80 (LA-G80), in UVB-induced photoaging, we conducted experiments on human Hs68 dermal fibroblasts. Using untargeted metabolomics, we explored the potential mechanisms underlying BL-G101 treatment in Hs68 cells by profiling differential metabolites in the intracellular and extracellular metabolomes. Results: Our results demonstrated that BL-G101 significantly inhibited UVB-induced reduction in collagen and hyaluronic acid (HA), whereas LA-G80 showed no notable effects. BL-G101 treatment also protects against UVB-induced oxidative stress, which was evidenced by significantly decreased MDA levels and enhanced SOD activity. Moreover, BL-G101 suppressed UVB-induced inflammation by significantly decreasing IL-1β and TNF-α levels. SA-β-gal staining revealed a reduction in senescent fibroblasts following BL-G101 treatment. Untargeted metabolomics suggested that the anti-photoaging effects of BL-G101 may involve the modulation of metabolic pathways of biosynthesis of cofactors, glycine, serine and threonine metabolism, and arginine biosynthesis. Conclusions: These preclinical findings demonstrate that BL-G101 reduces dermal photoaging, supporting its potential as a functional food ingredient against skin aging.

Background/Objectives: Skin photoaging represents a predominant form of extrinsic aging, characterized by structural and functional impairment of the skin barrier. In severe cases, it may precipitate dermatological diseases and even tumors. Given the prevalence and detrimental effects of skin photoaging, strategies for its effective prevention and mitigation have garnered significant research interest. Chrysanthemum morifolium Ramat cv. ‘Hangju’ contains diverse bioactive compounds, including flavonoids, phenylpropanoids, phenolic acids, and polysaccharides, which have been proven to exhibit antioxidant and anti-inflammatory effects. Methods: This study employed a UVB-induced mouse model of skin photoaging to evaluate the potential of dietary supplementation with Chrysanthemum morifolium Ramat cv. ‘Hangju’ flower extract (CME) in vivo. Results: In the photoaged skin of female SKH-1 hairless mice, dietary supplementation with CME significantly increased skin moisture content, reduced wrinkle formation, suppressed epidermal hyperplasia, enhanced collagen density, and suppressed the senescence marker expression and DNA damage marker expression. Analysis of the skin transcriptome suggested that CME could alter gene expression patterns and potentially modulate critical signaling pathways involved in skin homeostasis. Moreover, 16S rRNA sequencing indicated that CME mitigated UVB-induced gut microbiota dysbiosis. Conclusions: These preclinical findings reveal the anti-photoaging property of dietary CME supplementation and point to its potential application as a functional dietary supplement for promoting skin health.

Previous studies have reported the therapeutic effects of oleuropein (OP) consumption on the early stage of diabetic nephropathy and diabetic cardiomyopathy. However, the efficacy of OP on the long-course of these diabetes complications has not been investigated. Therefore, in this study, to investigate the relieving effects of OP intake on these diseases, and to explore the underlying mechanisms, db/db mice (17-week-old) were orally administrated with OP (200 mg/kg bodyweight) for 15 weeks. We found that OP reduced expansion of the glomerular mesangial matrix, renal inflammation, renal fibrosis, and renal apoptosis. Meanwhile, OP treatment exerted cardiac anti-fibrotic, anti-inflammatory, and anti-apoptosis effects. Notably, transcriptomic and bioinformatic analyses indicated 290 and 267 differentially expressed genes in the kidney and heart replying to OP treatment, respectively. For long-course diabetic nephropathy, OP supplementation significantly upregulated the cyclic guanosine monophosphate-dependent protein kinase (cGMP–PKG) signaling pathway. For long-course diabetic cardiomyopathy, p53 and cellular senescence signaling pathways were significantly downregulated in response to OP supplementation. Furthermore, OP treatment could significantly upregulate the transcriptional expression of the ATPase Na⁺/K⁺ transporting subunit alpha 3, which was enriched in the cGMP–PKG signaling pathway. In contrast, OP treatment could significantly downregulate the transcriptional expressions of cyclin-dependent kinase 1, G two S phase expressed protein 1, and cyclin B2, which were enriched in p53 and cellular senescence signal pathways; these genes were confirmed by qPCR validation. Overall, our findings demonstrate that OP ameliorated long-course diabetic nephropathy and cardiomyopathy in db/db mice and highlight the potential benefits of OP as a functional dietary supplement in diabetes complications treatment.

Photoaging, the primary cause of skin aging damage, results from chronic ultraviolet (UV) exposure, leading to dryness and wrinkle formation. Nutritional intervention has emerged as a practical approach for preventing and addressing the effect of skin photoaging. The primary aromatic compound isolated from clove oil, isoeugenol (IE), has antibacterial, anti-inflammatory, and antioxidant qualities that work to effectively restrict skin cancer cell proliferation. This investigation delved into the advantages of IE in alleviating skin photoaging using UVB-irradiated skin fibroblasts and female SKH-1 hairless mouse models. IE alleviated UVB-induced photodamage in Hs68 dermal fibroblasts by inhibiting matrix metalloproteinase secretion and promoting extracellular matrix synthesis. In photoaged mice, dietary IE reduced wrinkles, relieved skin dryness, inhibited epidermal thickening, and prevented collagen loss. Additionally, the intestinal dysbiosis caused by prolonged UVB exposure was reduced with an IE intervention. The results of Spearman’s analysis showed a strong correlation between skin photoaging and gut microbiota. Given the almost unavoidable UVB exposure in contemporary living, this research demonstrated the efficacy of dietary IE in reversing skin photoaging, presenting a promising approach to tackle concerns related to extrinsic skin aging.

Chronic ultraviolet (UV) exposure causes photoaging, which is primarily responsible for skin damage. Nutritional intervention is a viable strategy for preventing and treating skin photoaging. Eugenol (EU) presents anti-inflammatory and antioxidant properties, promotes wound healing, and provides contact dermatitis relief. This study explored the ability of EU to mitigate skin photoaging caused by UVB exposure in vitro and in vivo. EU alleviated UVB-induced skin photodamage in skin cells, including oxidative stress damage and extracellular matrix (ECM) decline. Dietary EU alleviated skin photoaging by promoting skin barrier repair, facilitating skin tissue regeneration, and modulating the skin microenvironment in photoaged mice. The transcriptome sequencing results revealed that EU changed the skin gene expression profiles. Subsequent pathway enrichment analyses indicated that EU might reverse the pivotal ECM–receptor interaction and cytokine–cytokine receptor interaction signaling pathways. Furthermore, EU alleviated the intestinal dysbiosis induced by chronic UVB exposure. Spearman analysis results further revealed the close connection between gut microbiota and skin photoaging. Considering the near-inevitable UVB exposure in modern living, the findings showed that the EU effectively reverted skin photoaging, offering a potential strategy for addressing extrinsic skin aging.

Scope: Excellent health‐promoting effects of cedrol (CED), including anti‐inflammatory, anti‐arthritic, and antinociceptive effects, have been reported. The present study aims to investigate the preventive effects of CED on high‐fat diet (HFD)‐induced obesity and the related metabolic syndrome, and to delineate the underlying mechanism.Methods and results: Ten‐week‐old C57BL/6J mice are fed chow, HFD, or HFD supplemented with CED (0.2% w/w) for 19 weeks. Results demonstrate that CED effectively reduces HFD‐induced body weight gain, decreases visceral fat pad weight, and significantly prevents adipocyte hypertrophy in mice. HFD‐induced hepatic steatosis, glucose intolerance, insulin resistance, and gluconeogenesis are ameliorated by CED supplementation. 16S rRNA analysis reveals that CED does not change gut microbiota composition at the phylum and genus levels, indicating that CED may have limited effects on gut microbiota in HFD‐fed mice. Further transcriptome analysis of epididymal white adipose tissue reveals reprogrammed RNA profiles by CED.Conclusion: These results demonstrate that incorporating CED in the diet can prevent HFD‐induced obesity and related metabolic syndrome, and highlight that CED can be a promising dietary component for obesity therapeutic intervention.

Odorant receptors (ORs) and taste receptors (TRs) are expressed primarily in the nose and tongue in which they transduce electrical signals to the brain. Advances in deciphering the dietary component-sensing mechanisms in the nose and tongue prompted research on the role of gut chemosensory cells. Acting as the pivotal interface between the body and dietary cues, gut cells “smell” and “taste” dietary components and metabolites by taking advantage of chemoreceptors—ORs and TRs, to maintain physiological homeostasis. Here, we reviewed this novel field, highlighting the latest discoveries pertinent to gut ORs and TRs responding to dietary components, their impacts on gut hormone secretion, and the mechanisms involved. Recent studies indicate that gut cells sense dietary components including fatty acid, carbohydrate, and phytochemical by activating relevant ORs, thereby modulating GLP-1, PYY, CCK, and 5-HT secretion. Similarly, gut sweet, umami, and bitter receptors can regulate the gut hormone secretion and maintain homeostasis in response to dietary components. A deeper understanding of the favorable influence of dietary components on gut hormone secretion via gut ORs and TRs, coupled with the facts that gut hormones are involved in diverse physiological or pathophysiological phenomena, may ultimately lead to a promising treatment for various human diseases. Graphical Abstract

Scope: Eugenol (EU), the major aromatic compound derived from clove oil, is being focused recently due to its potential in preventing several chronic conditions. Herein, this study aims to evaluate the potential of EU in obesity prevention and to delineate the mechanisms involved.Methods and results: Five‐week‐old male C57BL/6J mice are fed with high‐fat diet (HFD) or HFD supplemented with EU (0.2%, w/w) for 13 weeks. EU significantly reduces obesity‐related indexes including final body weight, body weight gain, adipocyte size, visceral fat‐pad weight, and fasting blood glucose. EU prevents HFD‐induced gut dysbiosis, as indicated by the increase of Firmicutes and decrease of Desulfobacterota at phylum level, and the increase of Dubosiella, Blautia, unclassified_f_Oscillospiraceae, and unclassified_f_Ruminococcaceae, and the decrease of Alistipes, Alloprevotella, and Bilophila at genus level. Notably, the obesity‐related indexes are positively correlated with the relative abundances of Bacteroides, unclassified_f_Lachnospiraceae, Colidextribacter, and Bilophila, and negatively correlated with the relative abundances of norank_f_Muribaculaceae and Lachnospiraceae_NK4A136_group. Moreover, the preventive effects of EU on obesity are accompanied by the transcriptomic reprogramming of white adipose tissue.Conclusion: These findings demonstrate that EU prevents the HFD‐induced adiposity and modulates gut dysbiosis, and highlight the potential of EU in obesity intervention as a functional dietary supplement.

Skin, the largest organ of human body, acts as a barrier to protect body from the external environment and is exposed to a myriad of flavor compounds, especially food- and plant essential oil-derived odorant compounds. Skin cells are known to express various chemosensory receptors, such as transient potential receptors, adenosine triphosphate receptors, taste receptors, and odorant receptors (ORs). We aim to provide a review of this rapidly developing field and discuss latest discoveries related to the skin ORs activated by flavor compounds, their impacts on skin health and disease, odorant ligands interacting with ORs exerting specific biological effects, and the mechanisms involved. ORs are recently found to be expressed in skin tissue and cells, such as keratinocytes, melanocytes, and fibroblasts. To date, several ectopic skin ORs responding to flavor compounds, are involved in different skin biological processes, such as wound healing, hair growth, melanin regulation, pressure stress, skin barrier function, atopic dermatitis, and psoriasis. The recognition of physiological role of skin ORs, combined with the fact that ORs belong to a highly druggable protein family (G protein-coupled receptors), underscores the potential of skin ORs responding to flavor compounds as a novel regulating strategy for skin health and disease.