A comparison of the in vitro and in vivo effect of Bulbine frutescens and B. natalensis on cutaneous wound healing. In recent years, there has been a growing interest in natural and traditional medicines for the treatment of wounds. Attempts to find agents that promote wound-healing and that are affordable, effective and non-toxic have a long history. In South Africa, several indigenous plants are used to treat wounds and burns. The merits of relatively few of these have been scientifically evaluated. One plant, indigenous to only southern Africa and widely used as a skin remedy is Bulbine of the Asphodelaceae family. This study therefore aimed to investigate the in vitro and in vivo effect of Bulbine frutescens and B. natalensis on cutaneous wound healing.
In vitro cell culture study: In vitro studies were carried out on dermal fibroblasts and keratinocytes cultured under standard conditions using Iscove's Modified Eagles Medium (MEM) and Dulbecco's MEM respectively. Cells were seeded into 96 well plates and once confluent, treated with varying concentrations of the leaf extract of B. frutescens and B. natalensis. These cultures were then subjected to MTT, WST-1 and BrdU tests to determine the cytotoxicity and proliferation effect of the extracts. In addition, migration of cells across a score was analysed over a 48 hour period.
In vivo animal study: Excisional wounds (5) and incisional (2) were created on the back of 12 domestic pigs. Mirror imaged wounds were created as control wounds. The excisional wounds were then biopsied at days 2, 4, 7, 10 and 16 and the incisional wounds were biopsied at day 16. The excisional wound tissue was used for biochemical and histological analysis. The rate of closure of the wounds was also recorded. Each wound was analyzed for its biochemical composition by estimating the total amount of protein, DNA, collagen and hexosamine that was present in the wound tissue. The wound healing process was also documented histologically (using haematoxylin and eosin and a Mallory's trichrome stain) and immunohistochemically (using anti- α smooth muscle actin, vascular endothelial growth factor and transforming growth factor β receptors I and II). The incisional wounds were used to test tensile strength of the healed wounds using a tensiometer.
In the in vitro studies, both extracts exhibited no cytotoxicity to either the fibroblast or keratinocyte cells. Cell proliferation was greater than 100% at concentrations of 0.1-5 and 100‐300μg/ml for Bulbine natalensis and at concentrations of 0.1μg/ml for Bulbine frutescens. There was no significant difference in the proliferative effects of the two leaf extracts on cell proliferation. The biochemical analysis of the wound tissue showed a significant increase in the collagen, protein and total DNA content of both B. frutescens and B. natalensis treated wounds when compared to the untreated wounds. There was no significant difference in the hexosamine content of the both B. frutescens and B. natalensis treated and untreated wounds. Analysis of the wound tissue displayed an increase rate of closure of the wound tissue treated with B. frutescens and B. natalensis when compared to the untreated wounds. Full re-epithelialisation of both treated wounds occurred sooner than in the untreated wounds.
Principal supervisor: Prof B Kramer (WITS)
Co-supervisor: Prof AM Viljoen