Effects of alpha-mangostin on inflammation and growth factors release by wound healing cells exposed to high glucose environment

Poor wound healing is a serious complication of diabetes mellitus, culminating in chronic, non-healing diabetic foot ulcers (DFU). The arises from disruptions in cellular and molecular pathways involved in wound healing. Diabetes impacts cell migration, cytokines release, growth factors, and proteases that are crucial for regulating and sustaining the healing process. Natural products like alpha (α)-mangostin, a xanthone from Garcinia mangostana Linn (GML) pericarp, are traditionally used for wound healing. However, their potential in diabetic wound healing is underexplored. This study investigates α-mangostin’s effects on inflammation, proliferation, and remodelling phases of wound healing under diabetic conditions in vitro. Human monocytic cells (THP-1), human coronary artery endothelial cells (HCAEC), and human dermal fibroblast cells (HDF) were exposed to 35 mM glucose for 72 hours to simulate diabetic conditions. These cells were then treated with α-mangostin (0.15, 2.5, and 5 µg/mL) for 24 hours. Carboxymethylcellulose (5 µg/mL) was used as a positive control. Cells incubated with glucose alone (35mM) served as a negative control called glucose control. A scratch assay was performed and the rate of cell migration was calculated. The protein and gene expression of IL-6, MMP-9, TIMP-2, and growth factors (PDGF, TGF-β, CTGF, VEGF, and BFGF) were measured by standard ELISA kits and quantitative real-time PCR. The study assessed α-mangostin’s effects on IL-6, MMP-9, TIMP-2, and key growth factors across wound healing phases using HCAEC, THP-1, and HDF cells under a high glucose environment. In the inflammatory phase, α-mangostin reduced IL-6 gene expression in HCAEC and THP-1 at all concentrations (p<0.05), with reduction of protein secretion found in HDF (0.15 µg/mL (p<0.001) and 5 µg/mL (p<0.0001). In the proliferative phase, 0.15 ug/mL α-mangostin accelerated HCAEC (p<0.001) and HDF (p<0.01) migration compared to glucose controls. For growth factors, in HCAEC cells, α-mangostin elevated PDGF gene expression (0.15 and 5 µg/mL (p<0.05), VEGF protein secretion (5 µg/mL, p<0.05), and BFGF gene/protein levels (0.15 and 2.5 ug/mL, p<0.01). In HDF cells, α-mangostin increased PDGF secretion (2.5 and 5 µg/mL, p<0.05), TGF-β gene/protein levels (0.15 and 2.5 ug/mL, p<0.05), and enhanced CTGF gene expression at all concentrations (p<0.05). For THP-1 cells, α-mangostin significantly increased PDGF gene/protein levels at all concentrations (p<0.05). Additionally, there was an increment of TGF-β, CTGF, VEGF and BFGF protein/gene levels in THP-1 incubated with α-mangostin at various concentrations. For remodelling phase, various concentrations of α-mangostin significantly reduced both the MMP-9 gene and/or protein levels in HCAEC, HDF and THP-1 cells (p<0.05). Conversely, α-mangostin increased TIMP-2 gene/protein levels in HCAEC and THP-1 at various concentrations (p<0.01). In conclusion, α-Mangostin reduced IL-6 gene expression and protein secretion in various cell types during the inflammatory phase. It also speeds up cell migration in the proliferative phase and increased the expression of growth factors like PDGF, VEGF, BFGF, TGF-β, and CTGF. In the remodeling phase, α-mangostin lowered MMP-9 levels and increased TIMP-2 expression. This study demonstrates that α-mangostin has beneficial effects on accelerating diabetic wound healing in vitro. Therefore, the findings from this study indicate the novel potential of α-mangostin in accelerating diabetic wound healing in vitro. This may lead to its development as a therapeutic agent for conditions characterised by high glucose levels, particularly diabetic foot ulcers.