Thin Layer Chromatography (TLC)
was investigated as a potential tool with which medicinal bark products used
in South African traditional healthcare may be authenticated. Dried bark
products are difficult to identify, and misidentification or adulteration
increasingly affect their appropriate use and accurate documentation of their
trade. A traditional medical practitioner pinpointed eight bark species used
in KwaZulu-Natal, South Africa, that are difficult to identify. These were Ekebergia
capensis (Meliaceae), Harpephyllum caffrum (Anacardiaceae), Rapanea
melanophloeos (Myrsinaceae), Schotia brachypetala (Caesalpiniaceae), Croton
sylvaticus (Euphorbiaceae), Albizia adianthifolia, Acacia sieberiana and Acacia
xanthophloea (Mimosaceae). Three reference bark samples of each species
were extracted in ethanol or hexane, separated on silica gel in petroleum
spirit : ethyl acetate : chloroform : formic acid (8:7:5:1), and treated
with anisaldehyde or vanillin reagents. TLC proved useful for showing similarities
in the phytochemical fingerprints of a single species, but less so in distinguishing
between the phytochemical fingerprints of different species. The technique
assisted in confirming the identity of several medicinal bark products.

South
African Journal of Botany 2002, 69(2): 165–169