Morphological and chemical variation of Stemona tuberosa from southern China – Evidence for heterogeneity of this medicinal plant species

Abstract

The occurrence of bioactive alkaloids and tocopherols was studied in 15 different provenances of Stemona tuberosa Lour. collected in southern China, to examine chemical variation of individuals that show notable differences in flower characteristics. Morphological variations stimulated examination of chemical characteristics of these individuals. Methanolic root extracts of 15 individuals of S. tuberosa were comparatively assessed with HPLC-UV-DAD/ELSD. Five of seven compounds were co-chromatographically identified. Two compounds were isolated and their structure elucidated using NMR and MS. Amounts of alkaloids and tocopherols were determined using HPLC-UV-DAD/ELSD with the external standard method. Five alkaloids, tuberostemonine (1), tuberostemonine A (2), neotuberostemonine (3), tuberostemonine N (4), stemoninine (5) and two 3,4-dehydrotocopherol derivatives were identified. Within S. tuberosa alkaloid accumulation tends either towards tuberostemonine (1) or stemoninine (5). All individuals show a notable co-occurrence of compounds 1 or 5 and 3,4-dehydro-δ-tocopherol (6). These results coincide with differences in flower morphology of S. tuberosa. Stemona tuberosa, as defined in the Flora of China, shows a remarkable variation in flower morphology and additionally in the accumulation of alkaloids. The obtained data show the need for future species delimitation to either species or subspecies level.

Structural classification and biological activities of Stemona alkaloids

“…In addition, some accessions deviated by a predominance of stemoninine (21). Floral characters suggested here a closer relatioship to S. tuberosa (Chen et al 2017).…”

Generation and classification of transcriptomes in two Croomia species and molecular evolution of CYC/TB1 genes in Stemonaceae

“…Because the roots and rhizomes of some Stemona and Croomia species are found to contain many bioactive and structurally unique alkaloids, such as protostemonine, stichoneurine, and croomine groups (Greger, 2006, Lin et al., 2006, Lin et al., 2008; Kongkiatpaiboon et al., 2011; Chen et al., 2017), they are widely used in Southeast Asian folk medicine to treat cough, traumatic injury, and enteric helminth worms (Lee et al., 2008, Chen et al., 2017). Thus, the family Stemonaceae has been a focus of phytochemical and pharmacological research (Kongkiatpaiboon et al., 2011; Chen et al., 2017). Among the four genera, Croomia exhibits a typical EA-ENA disjunct distribution across the Pacific Ocean, comprised of three herbaceous perennial species: Croomia heterosepala (Bak.)…”