Anti-inflammatory and cytoregulatory effects of Corymbia terminalis kino extracts on human keratinocytes

Kino, a reddish exudate from Corymbia terminalis traditionally used in Indigenous Australian medicine, was evaluated for its biological activity in vitro using HaCaT human keratinocytes. Methanolic kino extracts were tested for effects on cytocompatibility, migration, and inflammatory response. Morphological and CyQUANTⓇ assays showed dose-dependent suppression of keratinocyte proliferation, while MTT assays indicated preserved metabolic activity. Real-time cell analysis (RTCA) revealed enhanced keratinocyte migration at sub-toxic concentrations (0.8–1.6 μg/mL), suggesting a stimulatory effect on motility. Cytokine profiling demonstrated significant downregulation of IL-8 and biphasic modulation of IL-6. At higher extract concentrations (200 μg/mL), marked anti-inflammatory effects were observed. Inhibition of cyclooxygenase (COX-1/COX-2) was observed, although 5-lipoxygenase (5-LOX) inhibition remained minimal. These findings indicate that C. terminalis-derived kino extracts possess anti-inflammatory and cytoregulatory properties, supporting their potential therapeutic relevance. Further research is recommended to isolate active constituents and elucidate mechanisms of action.