Wound Healing Potential of Diterpenoids from the Hexane Fraction of Kaempferia galanga Rhizomes

Abstract

Kaempferia galanga, a member of the Zingiberaceae family, is widely cultivated throughout Southeast Asia and traditionally used for the treatment of inflammation, pain, and dyspepsia. This study aimed to isolate compounds responsible for anti-inflammation and wound treatment from K. galanga. Bioassay-guided isolation of ethanol extract was used in this study. The hexane fraction from ethanol extract of K. galanga demonstrated significant activity by inhibiting nitric oxide released from LPS-stimulated RAW264.7 cells. It was then isolated to obtain the active compounds. Ten diterpenes (KG1-10) isolated from this fraction were investigated to determine their wound healing properties including anti-inflammatory effect using RAW264.7 cells, amelioration of human dermal fibroblasts (HDF) proliferation and migration, effect on collagen production and oxidative stress in H2O2-induced HDF cells. It was found that 6b-acetoxysandaracopimaradiene-1a, 9a-diol (KG6) displayed the most capable anti-inflammatory effect, with an IC50 value of 18.7 µM. This compound also showed good cell proliferation and migration on day 3 at 116.5% and 88.5%, respectively. Furthermore, 6b,14a-dihydroxyisopimara-8(9),15-diene (KG8) meaningfully increased the viable cell (119.7%) and extended migration of HDF cells (88.4%) which was preferable effect than that of allantoin (102.4, 75.5%). 6b-Acetoxysandaracopimaradiene-9a-ol (KG2) significantly increased the collagen content (38.7 μg/ml) in HDF cells. In addition, 1a-hydroxy-14a-methoxyisopimara-8(9),15-diene (KG7) exhibited the highest cytoprotective activity by increasing the viability of H2O2-induced oxidative damage in HDF cells to 92.1%. The hexane fraction was analyzed using gas chromatography to identify the presence of active wound healing compounds, KG1-10. This fraction showed significant potential as a pharmaceutical ingredient in wound treatment products due to its strong wound healing properties.