Flavonoid compounds

Abstract:

Vascular plants produce a vast array of constituents often designated as “secondary” compounds (Harborne and Turner 1984; Seigler 1998). While no hard and fast criteria distinguish primary and secondary metabolites, in general, secondary compounds do not function directly in fundamental activities such as growth and development. The original designation “secondary” was applied because the compounds were thought to be “waste” products from primary metabolic pathways such as photosynthesis. It is now clear that these compounds have many functions, and thus the original name was a gross misnomer (Bohm 1998a, chap. 7). These compounds are typically of low molecular weight and are often also referred to collectively as “micromolecules” (Giannasi and Crawford 1986; Seigler 1998). Rationale for the Use of Flavonoids and Other Micromolecules in Systematic Studies Beginning in the late 1950s and early 1960s, micromolecules were employed for taxonomic-systematic purposes and for studying processes such as hybridization and the origin of polyploid species (Bate-Smith 1958, 1962; Alston and Turner 1963; Swain 1963; Harborne and Turner 1984). This new hybrid discipline of natural products chemistry and plant systematics was dubbed “chemical taxonomy,” “chemosystematics,” “biochemical systematics,” or other similar names (Alston and Turner 1963; Giannasi and Crawford 1986). For any new kind of comparative data introduced into plant systematics, perspectives on the value and utility of the data change through time. There is often an initial euphoria about the potential contributions of new information, and this is tempered through time until eventually the data are woven into the fabric of plant systematics as part of Constance’s (1964) unending synthesis. Harborne and Turner (1984, pp. 42, 44, tab. 4.2) compared and contrasted the advantages and disadvantages of micromolecules and morphology. Some of the perceived strengths of chemical characters are worthy of mention. The structures of micromolecules can be elucidated, and thus they represent distinct, contrasting characters as compared with morphological characters such as leaf shape, where many loci contribute to the phenotype of the leaf. Further, molecular structures are the products of biosynthetic pathways and usually more closely reflect, or may be equated to, genetic differences than is possible with morphology. With compounds such as flavonoids, it was initially thought that particular structures could be scored as either present or absent (detected or not), making them easier than scoring quantitative characters.

Año de publicación:

2017

Keywords:

Fuente:

scopus