The representatives of the Boraginaceae are trees, shrubs or herbs. The undivided leaves are seldom opposite. The flowers occur in boragoid or scorpioid cymes. The hairs are characteristic: bristle hairs, stellate hairs, hook-shaped hairs and cystoliths are frequent and generate the rough surface. The ovary is 2-4 celled and transforms into a drupe, nut or into mericarps (nutlets, synonym: 'Klausen'). The walls of the bristle hairs as well as the bases of the cystoliths may be impregnated with Si02 and/ or CaC03• Further chemical contents are the boragoid alkaloids (cynoglossin), allantoin and alkannapigments. Allantoin is a preferred form for the storage and transportation of nitrogen. It improves granulation and is consequently valued as a wound-healing remedy in Boraginaceae. Red dyes corresponding to esters of phenolic compounds are frequent in Boraginaceae with a thick taproot; they probably develop from colourless precursors when the plant is dried. Alkanna tinctoria TAUSCH. yields a red dye, alkannin, in its roots (alkanet root); it is a naphthoquinone derivative, which is permitted as a food dye. Certain species (Lithospermeae) have oestrogenic and contraceptive effects; phenolic compounds are probably the active principles.
1) South American medicinal plants : botany, remedial properties, and general use / I. Roth, H. Lindorf. Berlin ; New York : Springer, c2002. -- p. 492.