Chemosystematic evaluation of Aloe section Pictae (Asphodelaceae)

Abstract

a b s t r a c tThe chemosystematic value of UV-absorbing leaf constituents was considered in previously uncharacterised representatives of Aloe section Pictae, the problematic maculate species complex. Comparative data indicate that the anthrone C-glycoside, 60 -malonylnataloin (7-hydroxychrysaloin 6 0 -O-malonate) is typical of maculate species in East Africa, but is unconvincing as a synapomorphy for section Pictae. A naphthalene derivative found widely in Aloe, plicataloside, was detected in Aloe greatheadii. Biogeographical trends were observed in the occurrence of the flavonoids isoorientin (luteolin-6-Cglucoside) and isovitexin (apigenin 6-C-glucoside). Isoorientin is a common constituent of tropical and sub-tropical species of Aloe, whereas isovitexin is restricted to a few southern African species. Isoorientin and isovitexin co-occur in the southern African maculate species Aloe parvibracteata, and the disjunct West African maculate species, Aloe macrocarpa. This is the first report of isoorientin and isovitexin in maculate species of Aloe; the presence of flavonoids in section Pictae is of taxonomic interest.

Reinstatement ofAloe barbertoniaePole-Evans (Asphodelaceae: Alooideae) from northeastern South Africa

“…With their ability to hybridise and intergrade, the maculate aloes are amongst the most taxonomically challenging groups in the genus (Grace et al, , 2010. Recent fieldwork indicated that one of the eastern maculate aloes, A. barbertoniae Pole-Evans, warrants recognition at species level.…”

Reinstatement of Aloe graciliflora Groenew. (Asphodelaceae: Alooideae), a maculate aloe from north-east South Africa

“…The complex of maculate aloes is one of the most taxonomically challenging in the genus Aloe L. (Grace et al, 2009(Grace et al, , 2010. Species circumscription tends to be vague and contentious as populations of one species seemingly intergrade and hybridize with populations of neighbouring species.…”

CARACTERES ANATÔMICOS DE FOLHA DE Aloe maculata ALL., XANTHORRHOEACEAE

“…Esta compreende cerca de 35 gêneros e 900 espécies de monocotiledôneas, encontradas na Europa, na Ásia e na África (MOBOT, 2010). De acordo com Grace et al (2010), o gênero Aloe é formado de aproximadamente 500 espécies, ocorrentes na África, na Península Arábica e nas ilhas do Oceano Índico. No Brasil, esse táxon foi introduzido e os representantes são empregados como ornamentais e medicinais (SOUZA, LORENZI, 2008).…”

“…Mundialmente, muitas espécies de Aloe são utilizadas na medicina tradicional, enquanto que um pequeno grupo é coletado da flora espontânea ou cultivado como matéria-prima para a indústria de fitoterápicos. Estes são preparados à base do exsudato foliar, amarelo e de sabor amargo, ou do gel incolor proveniente do mesofilo mucilaginoso das folhas suculentas (GRACE et al, 2010).…”