Anti-oxidant effects of the extracts from the leaves of Chromolaena odorata on human dermal fibroblasts and epidermal keratinocytes against hydrogen peroxide and hypoxanthine–xanthine oxidase induced damage

In cutaneous tissue repair, oxidants and antioxidants play very important roles. In local acute and chronic wounds, oxidants are known to have the ability to cause as cell damage and may function as inhibitory factors to wound healing. The administration of anti-oxidants or free radical scavengers is reportedly helpful, notably in order to limit the delayed sequelae of thermal trauma and to enhance the healing process. Extracts from the leaves of Chromolaena odorata have been shown to be beneficial for treatment of wounds. Studies in vitro of these extracts demonstrated enhanced proliferation of fibroblasts, endothelial cells and keratinocytes, stimulation of keratinocyte migration in an in vitro wound assay, up-regulation of production by keratinocytes of extracellular matrix proteins and basement membrane components, and inhibition of collagen lattice contraction by fibroblasts. In this study, the anti-oxidant effects of both total ethanol and polyphenolic extracts from the plant leaves on hydrogen peroxide and hypoxanthine-xanthine oxidase induced damage to human fibroblasts and keratinocytes were investigated. Cell viability was monitored by a colorimetric assay. The results showed that for fibroblasts, toxicity of hydrogen peroxide or hypoxanthine xanthine oxidase on cells was dose-dependent. Total ethanol extract (TEE) at 400 and 800 microg/ml showed maximum and consistent protective cellular effect on oxidant toxicity at low or high doses of oxidants. The 50 microg/ml concentration of TEE also had significant and slightly protective effects on fibroblasts against hydrogen peroxide and hypoxanthine-xanthine oxidase induced damage, respectively. For keratinocytes, a dose-dependent relationship of oxidant toxicity was only seen with hydrogen peroxide but the protective action of the extract correlated with oxidant dosage. TEE at 400 and 800 microg/ml showed dose-dependent effects with both low and high concentration of oxidants. TEE at 50 microg/ml had no effect on keratinocytes. Pre-treatment with the extracts did not show a protective effect on cells. Polyphenolic extract exhibited a slight anti-oxidant effect. Protection of cells against destruction by inflammatory mediators may be one of the ways in which the extracts from the plant, C. odorata, contribute to wound healing.

Effect of burn healing liquid on keratinocyte and fibroblast proliferation and on collagen lattice contraction

OBJECTIVES

To investigate the effect of Burn Healing Liquid (BHL) on the proliferation of keratinocytes and fibroblasts and to explore the potential effect of BHL on fibroblast contraction.

METHODS

Human keratinocytes and dermal fibroblasts were cultured in media containing serial dilutions of BHL followed by cell proliferation determination assessed with MTT (3-[4, 5-dimehtylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide) assay at different time intervals. The in vitro collagen lattice contraction model was utilized for determining the contractility of fibroblasts cultured in BHL containing medium.

RESULTS

The 1:10(7) dilution of BHL enhanced the growth of both keratinocytes and fibroblasts whereas the 1:10 dilution increased the growth of keratinocytes only. Collagen lattice contraction was inhibited dose-dependently by BHL and such an inhibition could be reversed by switching BHL containing medium to normal medium containing 10% fetal calf serum.

CONCLUSION

BHL enhances the growth of both keratinocytes and fibroblasts and reversibly inhibits the fibroblast contraction in collagen lattice.