Chemotaxonomic studies in Leguminosae (from Pakistan) with reference to Phenolics

Abstract

Phenolic constituents in the members of the family Leguminosae have been investigated from Pakistan. The subfamily Mimosoideae consist of c.11 genera and 56 species, and Caesalpinioideae include C.15 genera and 52 species from Pakistan. A total of 23 genera with 45 species (and 6 sub species) were analysed in the present investigation, of which 8 genera and 16 species (and 4 sub species) belong to the sub-family Mimosoidae, 10 genera and 23 species (one with 2 sub-species) to Caesalpinioideae, and 5 genera with 6 species to the subfamily Papilionoideae. Leaves of 181 samples were analysed for phenolic constitutents by both ascending and descending one and two dimensional paper and thin layer chromatography, of which Mimosoideae includes 78, Caesalpinioideae 89 and Papilionoideae 14 samples.

The genera investigated for phenolics at present are Acacia, Albizia, Mimosa, Prosopis, Pithecellobium, Leucaena, Adenanthera, Samanea, Bauhinia, Cassia, Caesalpinia, Cercis, Tamarindus, Hardwickia, Parkinsonia, Peltophorum, Delonix, Millettia, Dalbergia, Indigofera, Vicia and Lathyrus. A total of 90 phenolic compounds have been tentatively identified in these genera by using authentic markers, Rf values comparable to literature values, Color reactions with spray reagents and UV-fluorescence. A number of species have been confirmed for caffeic acid, p-coumaric acid, kaempferol, quercetin, rutin, myricetin, lutolin, pelargonidin and malvidin on the basis of UV- spectral properties using shift reagents.

Plants have been analysed for interplant and interlocality chemical differences and relationships etc. This revelead the geographical, environmental and ecological stablity of the compounds, clearly indicating that this approach is significant for taxonomic judgements.

Chemical differences are distinct between tree and herbaceous habit of plants which might be interesting for phylogenetic interpretation.