TETRAHYDROANTHRACENES AS MARKERS FOR SUBTERRANEAN ANTHRANOID METABOLISM IN ALOE SPECIES

Anthranoids in the roots of 14 Aloe species were surveyed by a novel h igh-performance liquid chromatographic method and photodiode-array det ection and, in leaves of the same species, by thin-layer chromatograph y. Whereas diastereomeric anthrone-C-glycosyls were detectable in the majority of leaf samples, these compounds as well as anthrone aglycone s were shown to be absent in root material. The anthraquinone aglycone chrysophanol was found in every root extract. Roots of ten species co ntained the tetrahydroanthracene aglycone aloesaponol I, which was iso lated as a major anthranoid from root and rhizome material of A. succo trina Lam. Three of the remaining four species exhibited compounds wit h UV-VIS spectra analogous to aloesaponols III/IV. The substitution pa ttern of the compounds detected indicates striking differences between subterranean and aerial anthranoid biosynthesis in Aloe. With regard to distribution and accumulation of tetrahydroanthracenes within the i ndividual plant as well as in the species examined here, these anthran oids are suggested to be specific markers for subterranean Aloe metabo lism.