An empirical study on the underutilized medicinal genus Kaempferia from India revealed cytological and genetic variability

Abstract

The genus Kaempferia L., consisting of aromatic and ornamental species found in east and south-east Asia, have profound ethno-medicinal usages as antimicrobial and anticancer agents, attributable to presence of novel cyclohexane derivatives, flavonoids and di-terpenes. Represented by only 7 species in India, a comprehensive genetic study of Kaempferia from the country is lacking. We present here a study of 4 species of this genus from India, namely, K. rotunda, K. galanga, K. elegans and K. angustifolia. Cytological analyses revealed distinct inter-specific ploidy and consequent somatic chromosome number variations (2n = 22 to 2n = 54). High inter- and intra-chromosomal variability was observed with chromosome lengths ranging from 0.87 to 6.63 µm, constriction types varying from median to sub-median range and different secondary constrictions, along with contrasting values of asymmetry indices. RAPD and ISSR analyses of 8 accessions produced 1,398 polymorphic bands, their sizes ranging from 100 to 2000 bp; percentage polymorphism varying from 84 to 100%. UPGMA dendrogram generated using the polymorphic fragments showed Jaccard's similarity coefficient value varying between 0.07 and 0.93, producing 3 separate clusters for the studied Kaempferia species. ITS, matK and rbcL loci sequence analyses also confirmed high level of inter-specific variability of Kaempferia. Genetic variation revealed in this study could indicate chemotypic differences in Kaempferia and will direct our future research for a wider cytogenetic and phytochemical investigation including all the Indian species that would open up avenues for judicious exploitation of these medicinally important plants.