Anti-Skin Inflammatory and Anti-Oxidative Effects of the Neoflavonoid Latifolin Isolated from Dalbergia odorifera in HaCaT and BJ-5ta Cells

Skin is the first line of defense in the body against external stimulation and injury. Inflammation and oxidative stress in skin cells are the initiators and promoters of several skin diseases. Latifolin is a natural flavonoid isolated from Dalbergia odorifera T. Chen. This study aimed to evaluate the anti-inflammatory and antioxidant properties of latifolin. The anti-inflammatory effects were evaluated using tumor necrosis factor-α/interferon-γ (TNF-α/IFN-γ)-treated HaCaT cells, revealing that latifolin inhibited the secretion of Interleukin 6 (IL-6); Interleukin 8 (IL-8); Regulated upon Activation, Normal T Cell Expressed and Presumably Secreted (RANTES); and Macrophage-derived chemokine (MDC) while decreasing the expression of Intercellular Adhesion Molecule 1 (ICAM-1). The results of western blots and immunofluorescence demonstrated that the activation of Janus kinase 2 (JAK2), Signal transducer and activator of transcription 1 (STAT1), Signal transducer and activator of transcription 3 (STAT3), and nuclear factor kappa-light-chain-enhancer of activated B (NF-κB) cells signaling pathways were significantly inhibited by latifolin. The antioxidant properties were evaluated using t-BHP-induced BJ-5ta cells. Latifolin increased the viability of t-BHP-induced BJ-5ta cells. Additionally, fluorescent staining of reactive oxygen species (ROS) showed that the production of ROS was inhibited by latifolin. Additionally, latifolin reduced the phosphorylation of p38 and JNK. The results indicate that latifolin has potential anti-inflammatory and antioxidant properties, and may be a candidate natural compound for the treatment of skin diseases.


Introduction
The skin is the largest organ in the human body. It acts as a barrier between the internal and external environments of the human body. It protects the body from harmful stimuli such as allergens, UV radiation, microbes, and other irritants [1,2]. Inflammation is a response to skin barrier damage. At the molecular level, the inflammatory response entails a number of intricate repair pathways connected to skin differentiation, innate immune response, and skin barrier restoration [3]. When the inflammatory response initially occurs, keratinocytes, innate immune cells, dendritic cells, and inflammatory cytokines such as Interleukin-1 alpha (IL-1α), tumor necrosis factor-α (TNF-α), and Interleukin 6 (IL-6) are released by activated mast cells to cause chemokines of chemotaxis, which draw immune cells to areas of injury and infection [4]. A mild inflammatory response facilitates tissue repair and infection control. However, chemokines secreted by activated keratinocytes can further exacerbate skin tissue damage in the vicinity of the inflammatory response. The intensity and resolution of inflammation determine the severity of skin tissue damage, and regulation of inflammation is important for maintaining skin homeostasis [5,6].
Skin is the largest organ of the human body. Collagen from the connective tissue of the dermis serves as a dynamic scaffold for cell attachment, critically regulating its function, and is also a repository and regulator of effective biological mediators (growth factors,

Effects of Latifolin on Secretion of IL-6, IL-8, MDC, and RANTES in TNF-α/IFN-γ-Treated HaCaT Cells
First, we isolated latifolin from D. odorifera heartwood for this study, and then its structure ( Figure 1A) was identified by referring to a previous study [15]. Keratinocytes are the primary epidermal cells that play a key role in the pathogenesis of skin inflammatory diseases. Keratinocytes maintain the recruitment and activation of inflammatory cells by producing various inflammatory mediators (such as cytokines and chemokines) [16]. As shown in Figure 1B-E, the secretion of Interleukin 6 (IL-6); Interleukin 8 (IL-8); Regulated upon Activation, Normal T Cell Expressed and Presumably Secreted (RANTES); and Macrophage-derived chemokine (MDC) were significantly increased by TNF-α/IFN-γ co-stimulation. Latifolin exhibited strong inhibitory effects on IL-6, IL-8, MDC, and RANTES.

Effects of Latifolin on JAK2/STAT1(3) Pathway in HaCaT Cells
The Janus kinase/Signal transducer and activator of transcription/pathway mediate inflammatory responses and alter the natural skin barrier, thereby stimulating the interaction between multiple cytokines to aggravate skin inflammatory symptoms [20]. As shown in Figure 3A-D, the expression of JAK2, STAT1, and STAT3 phosphorylation increased significantly after stimulation with 10 ng/mL TNF-α/IFN-γ, and latifolin significantly downregulated the phosphorylation of JAK2, STAT1, and STAT3. These findings suggested that latifolin may regulate the JAK2/STAT1/3 signaling pathway in HaCaT cells. , and RANTES (F) in TNF-α/IFN-γ-stimulated HaCaT cells. Cells were treated with latifolin (10-80 µM) for 24 h, and the cytotoxicity was evaluated. The cell culture supernatant was used to check ELISA kits. The data are represented as the mean ± SD (n = 3). * p < 0.05, ** p < 0.01 vs. TNF-α/IFN-γ-treated group.

Effects of Latifolin on TNF-α/IFN-γ-Treated ICAM-1 Expression
Intercellular Adhesion Molecule 1 (ICAM-1) is expressed in distinct cell types, and plays an important role in cell-cell and extracellular matrix interactions, cell signaling, and immune processes [17]. ICAM-1 expression increased significantly in areas of skin inflammation. The effects of latifolin on TNF-α/IFN-γ-induced ICAM-1 expression were detected using the western blot. As shown in Figure 2A

Effects of Latifolin on TNF-α/IFN-γ-Treated ICAM-1 Expression
Intercellular Adhesion Molecule 1 (ICAM-1) is expressed in distinct cell ty plays an important role in cell-cell and extracellular matrix interactions, cell s and immune processes [17]. ICAM-1 expression increased significantly in area inflammation. The effects of latifolin on TNF-α/IFN-γ-induced ICAM-1 express detected using the western blot. As shown in Figure 2A

Effects of Latifolin on JAK2/STAT1(3) Pathway in HaCaT Cells
The Janus kinase/Signal transducer and activator of transcription/pathway inflammatory responses and alter the natural skin barrier, thereby stimulating action between multiple cytokines to aggravate skin inflammatory symptoms shown in Figure 3A-D, the expression of JAK2, STAT1, and STAT3 phosphory creased significantly after stimulation with 10 ng/mL TNF-α/IFN-γ, and latifoli cantly downregulated the phosphorylation of JAK2, STAT1, and STAT3. These suggested that latifolin may regulate the JAK2/STAT1/3 signaling pathway in HaC

Effects of Latifolin on JAK2/STAT1(3) Pathway in HaCaT Cells
The Janus kinase/Signal transducer and activator of transcription/pathway mediate inflammatory responses and alter the natural skin barrier, thereby stimulating the interaction between multiple cytokines to aggravate skin inflammatory symptoms [20]. As shown in Figure 3A-D, the expression of JAK2, STAT1, and STAT3 phosphorylation increased significantly after stimulation with 10 ng/mL TNF-α/IFN-γ, and latifolin significantly downregulated the phosphorylation of JAK2, STAT1, and STAT3. These findings suggested that latifolin may regulate the JAK2/STAT1/3 signaling pathway in HaCaT cells.

Effects of Latifolin on NF-κB Signaling Pathways in HaCaT Cells
Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a prom of kappa light-chain synthesis. It is associated with inflammation, angiogenesis, cell liferation, and telomerase gene expression [21,22], and is involved in the inflamma response of the skin [23]. As shown in Figure 4A,B, the western blotting results dem strate that the p65 translocation and p-IκBα phosphorylation induced by TNF-α/IF were inhibited by latifolin. As shown in Figure 4C, immunofluorescence results indic that p65 translocation activity was inhibited. It revealed that latifolin has a regulator fect on NF-κB signaling pathway; thus, it may contribute to reducing the inflamma response.

Effects of Latifolin on NF-κB Signaling Pathways in HaCaT Cells
Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a promoter of kappa light-chain synthesis. It is associated with inflammation, angiogenesis, cell proliferation, and telomerase gene expression [21,22], and is involved in the inflammatory response of the skin [23]. As shown in Figure 4A,B, the western blotting results demonstrate that the p65 translocation and p-IκBα phosphorylation induced by TNF-α/IFN-γ were inhibited by latifolin. As shown in Figure 4C, immunofluorescence results indicated that p65 translocation activity was inhibited. It revealed that latifolin has a regulatory effect on NF-κB signaling pathway; thus, it may contribute to reducing the inflammatory response.

Effects of Latifolin on NF-κB Signaling Pathways in HaCaT Cells
Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a promoter of kappa light-chain synthesis. It is associated with inflammation, angiogenesis, cell proliferation, and telomerase gene expression [21,22], and is involved in the inflammatory response of the skin [23]. As shown in Figure 4A,B, the western blotting results demonstrate that the p65 translocation and p-IκBα phosphorylation induced by TNF-α/IFN-γ were inhibited by latifolin. As shown in Figure 4C, immunofluorescence results indicated that p65 translocation activity was inhibited. It revealed that latifolin has a regulatory effect on NF-κB signaling pathway; thus, it may contribute to reducing the inflammatory response.

Effects of Latifolin on Cell Viability in t-BHP-Induced BJ-5ta Cells
The results of the cytotoxicity assay of latifolin on BJ-5ta cells (shown in Figure 5A) revealed that 40 µM latifolin exhibited a certain degree of cytotoxicity. Therefore, the concentrations of latifolin utilized in the next experiments were 5, 10, and 20 µM. The effect of latifolin on t-BHP-induced BJ-5ta cell death was tested using a cell viability assay, and the results are demonstrated in Figure 5B. BJ-5ta cells were pretreated with latifolin (5-20 µM) for 3 h, followed by treatment with t-BHP (75 µM). Cell viability was reduced by t-BHP, and it was observed that latifolin can significantly increase cell viability in a dose-dependent manner.
The results of the cytotoxicity assay of latifolin on BJ-5ta cells (shown in Figure revealed that 40 µM latifolin exhibited a certain degree of cytotoxicity. Therefore, the c centrations of latifolin utilized in the next experiments were 5, 10, and 20 µM. The eff of latifolin on t-BHP-induced BJ-5ta cell death was tested using a cell viability assay, the results are demonstrated in Figure 5B. BJ-5ta cells were pretreated with latifolin (5 µM) for 3 h, followed by treatment with t-BHP (75 µM). Cell viability was reduced b BHP, and it was observed that latifolin can significantly increase cell viability in a do dependent manner.

Effects of Latifolin on ROS Production Induced by t-BHP in BJ-5ta Cells
Oxidative stress in dermal fibroblasts plays a crucial role in the pathogenesis of v ous skin diseases [24]. Antioxidants are essential for inhibition of oxidative damage protection of skin; therefore, we measured the effect of latifolin on t-BHP-induced in cellular ROS accumulation using t-BHP in BJ-5ta cells. Fluorescence microscopy ima indicated that latifolin inhibited t-BHP-induced ROS production in BJ-5ta cells (Figure both 10 and 20 µM latifolin exhibited this ROS inhibition effect.

Effects of Latifolin on ROS Production Induced by t-BHP in BJ-5ta Cells
Oxidative stress in dermal fibroblasts plays a crucial role in the pathogenesis of various skin diseases [24]. Antioxidants are essential for inhibition of oxidative damage and protection of skin; therefore, we measured the effect of latifolin on t-BHP-induced intracellular ROS accumulation using t-BHP in BJ-5ta cells. Fluorescence microscopy images indicated that latifolin inhibited t-BHP-induced ROS production in BJ-5ta cells ( Figure 6); both 10 and 20 µM latifolin exhibited this ROS inhibition effect. The results of the cytotoxicity assay of latifolin on BJ-5ta cells (shown in Figure  revealed that 40 µM latifolin exhibited a certain degree of cytotoxicity. Therefore, the c centrations of latifolin utilized in the next experiments were 5, 10, and 20 µM. The eff of latifolin on t-BHP-induced BJ-5ta cell death was tested using a cell viability assay, the results are demonstrated in Figure 5B. BJ-5ta cells were pretreated with latifolin (5 µM) for 3 h, followed by treatment with t-BHP (75 µM). Cell viability was reduced b BHP, and it was observed that latifolin can significantly increase cell viability in a do dependent manner.

Effects of Latifolin on ROS Production Induced by t-BHP in BJ-5ta Cells
Oxidative stress in dermal fibroblasts plays a crucial role in the pathogenesis of v ous skin diseases [24]. Antioxidants are essential for inhibition of oxidative damage protection of skin; therefore, we measured the effect of latifolin on t-BHP-induced in cellular ROS accumulation using t-BHP in BJ-5ta cells. Fluorescence microscopy ima indicated that latifolin inhibited t-BHP-induced ROS production in BJ-5ta cells (

Effects of Latifolin on Mitogen-Activated Protein Kinase (MAPK) Signaling Pathways in BJ-5ta Cells
MAPK activation causes cell death. Studies have shown that ROS mediate MA phosphorylation, leading to neuronal cell death [25]. Therefore, we investigated whet latifolin inhibited MAPK activation. The t-BHP increased the phosphorylation of p38

Effects of Latifolin on Mitogen-Activated Protein Kinase (MAPK) Signaling Pathways in BJ-5ta Cells
MAPK activation causes cell death. Studies have shown that ROS mediate MAPK phosphorylation, leading to neuronal cell death [25]. Therefore, we investigated whether latifolin inhibited MAPK activation. The t-BHP increased the phosphorylation of p38 and JNK, and latifolin inhibited the phosphorylation of p38 and JNK in a dose-dependent manner ( Figure 7A,B). These results suggest that latifolin exhibits protective effects against t-BHP via the MAPK pathway (p38 and JNK).

Int. J. Mol. Sci. 2023, 24, x FOR PEER REVIEW
6 o JNK, and latifolin inhibited the phosphorylation of p38 and JNK in a dose-depend manner ( Figure 7A,B). These results suggest that latifolin exhibits protective eff against t-BHP via the MAPK pathway (p38 and JNK).

Discussion
Skin barrier disruption and immune mechanisms may play a prominent role in onset and support of skin diseases, such as atopic dermatitis, contact dermatitis, and p riasis [26]. The most popular class of anti-inflammatory medications is called corticos oids, yet a number of studies have documented substantial adverse consequences of lo term topical corticosteroid therapy, including skin shrinkage, telangiectasia, and relia on recurrence. The lack of treatment adherence caused by these adverse effects drive quest for novel, broadly effective topical and systemic medications that could update augment the treatment of skin diseases [27].
Natural substances have unique advantages in treating many chronic diseases; example, there are multiple action targets and few side effects. These have been wid used in skin care for hundreds of years, and we are currently searching for new natu substances with biological activities. These substances can promote skin health and p tect the skin from harmful factors [28,29]. Reports showed that flavonoids from D. odori have good therapeutic effects on cardiovascular diseases, blood diseases, and other flammation-related diseases [16]. The anti-skin inflammatory effects of D. odorifera, or constituent compound, have not yet been studied. This study investigated the effect latifolin isolated from D. odorifera on skin inflammation and oxidative stress. The ski the largest organ in the human body, and acts as the first protective system from exter threats such as noxious substances and pathogens [30]. As the most important cell typ the skin, keratinocytes play an important immune function. By secreting cytokines a chemokines, keratinocytes can recruit, activate, and regulate immune cells [30,31]. Oxi tive stress can cause significant damage to the skin, reducing ECM proteins in fibrobla which are important for maintaining skin health. When ECM proteins are damaged, t can weaken the protective function of the skin, leading to slow wound repair and frequ

Discussion
Skin barrier disruption and immune mechanisms may play a prominent role in the onset and support of skin diseases, such as atopic dermatitis, contact dermatitis, and psoriasis [26]. The most popular class of anti-inflammatory medications is called corticosteroids, yet a number of studies have documented substantial adverse consequences of long-term topical corticosteroid therapy, including skin shrinkage, telangiectasia, and reliance on recurrence. The lack of treatment adherence caused by these adverse effects drives a quest for novel, broadly effective topical and systemic medications that could update or augment the treatment of skin diseases [27].
Natural substances have unique advantages in treating many chronic diseases; for example, there are multiple action targets and few side effects. These have been widely used in skin care for hundreds of years, and we are currently searching for new natural substances with biological activities. These substances can promote skin health and protect the skin from harmful factors [28,29]. Reports showed that flavonoids from D. odorifera have good therapeutic effects on cardiovascular diseases, blood diseases, and other inflammationrelated diseases [16]. The anti-skin inflammatory effects of D. odorifera, or its constituent compound, have not yet been studied. This study investigated the effects of latifolin isolated from D. odorifera on skin inflammation and oxidative stress. The skin is the largest organ in the human body, and acts as the first protective system from external threats such as noxious substances and pathogens [30]. As the most important cell type in the skin, keratinocytes play an important immune function. By secreting cytokines and chemokines, keratinocytes can recruit, activate, and regulate immune cells [30,31]. Oxidative stress can cause significant damage to the skin, reducing ECM proteins in fibroblasts, which are important for maintaining skin health. When ECM proteins are damaged, they can weaken the protective function of the skin, leading to slow wound repair and frequent skin inflammation [32].
Keratinocytes can express the receptor of TNF-α and IFN-γ. Stimulation with these cytokines can induce the expression of various proinflammatory genes in keratinocytes, such as CXCL5, CXCL8 (also known as IL-8), and intercellular adhesion molecule 1 (ICAM-1) [33]. In this study, we explored the effects of latifolin on skin inflammation and oxidative stress. When the epidermal barrier of the skin is damaged, it secretes many inflammatory factors and chemokines, such as IL-6, IL-8, IL-1β, RANTES, MDC, and Thymus and Activation Regulated Chemokine (TARC), which will further promote keratinocytes to contribute to the emergence of inflammatory skin diseases. Inhibiting the secretion of proinflammatory factors and chemokines is an effective strategy for treating inflammatory skin diseases. Latifolin demonstrated an adequate effective activity on cytokines and chemokines, such as IL-6, IL-8, MDC, and RANTES in TNF-α/IFN-γ-stimulated HaCaT cells (Figure 1).
The NF-κB pathway is a classic pro-inflammatory signaling pathway that enhances the expression of pro-inflammatory cytokines, chemokines, and adherence factors [34]. Nuclear entry and exit of NF-κB regulate inflammation response. When exposed to drugs, the nuclear translocation of p65 showed significant changes [35]. The nuclear translocation was promoted by depredating the phosphorylated IKB proteins, and p65 in the nucleus promoted IKB transcription. In our results, p65 was significantly activated in cells exposed to TNF-α/IFN-γ; the phosphorylated IKBα also showed a significant increase. Latifolin significantly inhibits the expression of p65 in the nucleus and its nuclear translocation, and increased dephosphorylation of IKBα ( Figure 4). These results suggest that latifolin can significantly regulate the NF-κB pathway to exert an anti-inflammatory effect.
The JAK/STAT is a transduction pathway that is widely expressed in many cells. The JAK/STAT pathway is activated in several immunological and inflammatory disorders [36]. The signal transduction of cytokines, chemokines, and growth hormones is significantly mediated by JAK. After attaching to the cell surface JAK receptor, the ligand phosphorylates, particularly tyrosine, form residues in the receptor's cytoplasmic tail, generating a docking site for STATs. STATs are phosphorylated after being attracted to the receptor. Once homoor heterodimers have formed, phosphorylated STATs continue to the nucleus to stimulate gene transcription [37]. It is known that the JAK2/STAT3 pathway can be used to treat skin irritation. We examined whether latifolin prevented JAK2, STAT1, and STAT3 from becoming phosphorylated. The outcomes demonstrated that JAK2, STAT1, and STAT3 activation are inhibited by latifolin (Figure 3). These findings imply that latifolin's antiinflammatory actions are caused by its suppression of the JAK/STAT system.
Reactive oxygen species (ROS) are common by-products of oxidative energy metabolism, including oxygen ion and peroxide [38], and are considered to be important physiological regulators of several intracellular signaling pathways, including the MAPK pathway. Excessive ROS cause serious damage to biological molecules in cells and mitochondria, leading to inflammation and oxidative stress. Recently, studies have shown that activation of ERK enhances cell survival, while activation of JNK and p38 MAPK induces apoptosis. These reports suggest that ERK has a protective function against cellular stress, while activation of p38 MAPK/JNK leads to apoptosis-induced death [39,40]. In this study, images of t-BHP-induced BJ-5ta cells showed that latifolin reduced the generation of ROS ( Figure 6). ERK, JNK, and p38 respond to oxidative stress, and are activated by ROS production. ERK activation controls cell proliferation; JNK and p38 respond to cell stress and contribute to inflammation and apoptosis [29]. In our results, latifolin downregulated the phosphorylation of p38 and JNK in t-BHP-induced BJ-5ta cells, but did not affect ERK phosphorylation (Figure 7).

The Structure Identification of Latifolin
The NMR spectra used for the analysis of latifolin were recorded in CD 3 OD solution after dissolving, using a JEOL (Akishima, Tokyo, Japan) Eclipse 400 MHz spectrometer (400 MHz for 1 H and 100 MHz for 13 C). The chemical shifts were referenced to the residual solvent peaks and are summarized as follows. By comparing the chemical shift analysis results of NMR with those reported in the reference, the compound was identified to be structurally latifolin [19]. Latifolin

IL-6, IL-8, MDC, and RANTES Detection in Cell Supernatant
HaCaT cells were plated in 24-well plates, pretreated for 3 h with latifolin (10, 20 and 40 µM), and then stimulated for 24 h with TNF-α/IFN-γ (5 ng/mL each). Following the manufacturer's instructions, an ELISA kit was used to gauge the levels of IL-6, IL-8, RANTES, and MDC in the cell supernatants in accordance with the manufacturer's recommendations.

Extraction of Total, Nuclear, and Cytosolic Protein
Latifolin was used as a pretreatment on HaCaT cells for 10-40 µM. The cells were stimulated with TNF-α/IFN-γ (5 ng/mL each) for 24 h in order to analyze ICAM-1 using a western blot. The cells were stimulated with TNF-α/IFN-γ for 15 min in order to analyze the levels of p-IκBα, IκBα, p65, p-JAK2, p-STAT1, and p-STAT3. Cells were collected and lysed in RIPA buffer for total protein analysis. To undertake nuclear and cytoplasmic protein analysis, the cells were collected, and the proteins were extracted using a Nuclear Extraction Kit (Cayman Chemical, MI, USA) in accordance with the manufacturer's instructions. BJ-5ta cells were pre-treated with latifolin (5-20 µM), and then exposed to t-BHP (75 µM) for 1 h before being collected and lysed using RIPA buffer. Prior to use, all proteins were kept at −80 • C.

Western Blot Analysis
SDS-PAGE was used to separate the obtained proteins, and the membranes were then transferred to nitrocellulose. The membrane was blocked with 5% skim milk for 60 min, treated overnight at 4 • C with the appropriate primary antibodies (1:1000 dilution), and then incubated for 1 h at room temperature (25 • C) with a secondary antibody conjugated with horseradish peroxidase (1:5000 dilution). Certain proteins were identified using an ECL solution after being cleaned with TBST. Using ImageJ software, the bands' optical density was examined (National Institutes of Health, Rockville, MD, USA).

Immunofluorescence Analysis
Immunofluorescence was used to identify the translocation of NF-κB. On glass chamber slides, HaCaT cells were plated, pretreated with latifolin (40 µM) for 3 h, and then stimulated with TNF-α/IFN-γ for 15 min. Cells were permeabilized, blocked, fixed in 4% paraformaldehyde, and then treated with NF-κB antibodies and secondary antibodies that were FITC-labeled. Cells were incubated for 5 min, then mounted on glass slides with coverslips. Using a fluorescent microscope, cells were examined and captured on camera (Nikon Optical Co, Tokyo, Japan).

ROS Staining
BJ-5ta cells were seeded in 6-well plates overnight and treated with latifolin (20 and 40 µM) for 3 h before being stimulated with t-BHP (75 µM) for 1 h. The cells were washed twice with PBS and then stained with DCF-DA (FBS-free medium) for 20 min at 37 • C. The fluorescent staining was observed using a fluorescence microscope (Nikon Eclipse, Tokyo, Japan).

Statistical Analysis
The results are presented as mean ± standard deviation (SD). One-way analysis of variance (ANOVA) was performed using GraphPad Software (San Diego, CA, USA), and significance was tested using Duncan's multiple comparison test. Statistical significance was set at * p < 0.05, ** p < 0.01, *** p < 0.001 vs. the TNF-α/IFN-γ-treated group/t-BHPtreated group.

Conclusions
In conclusion, latifolin, isolated from D. odorifera heartwood, has anti-inflammatory and antioxidant properties. In TNF-α/IFN-γ-stimulated HaCaT keratinocytes, latifolin could inhibit inflammatory cytokine and chemokine secretion and the expression of ICAM-1. Activation of the JAK2, STAT1, STAT3, and NF-κB signaling pathways was also inhibited by latifolin. In t-BHP-stimulated BJ-5ta fibroblasts, latifolin increased cell viability and inhibited ROS production. Latifolin also inhibited p38 and JNK activation. This study demonstrates that latifolin has a certain regulatory and protective effect on skin inflammation, as well as a certain regulatory effect on oxidative stress. It has the potential to become a candidate compound for the treatment of skin inflammation-related diseases, and can also be used as a cosmetic raw material.

Institutional Review Board Statement: Not applicable.
Informed Consent Statement: Not applicable.

Data Availability Statement:
The data presented in this study are available. Data supporting the findings of this study are available upon request from the corresponding author.

Conflicts of Interest:
The authors declare no conflict of interest.