Anti-inflammatory and cytoregulatory effects of <i>Corymbia terminalis</i> kino extracts on human keratinocytes

Kino, a reddish exudate from <i>Corymbia terminalis</i> traditionally used in Indigenous Australian medicine, was evaluated for its biological activity <i>in vitro</i> 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 <i>C. terminalis</i>-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.