Chemical Constituents in Hybrids of Ligularia tongolensis and L. cymbulifera: Chemical Introgression in L. tongolensis.

Two samples with morphologies intermediate between Ligularia tongolensis and L. cymbulifera were collected in Desha, Sichuan Province, and one, in Pachahai, Yunnan Province, P. R. China. The DNA sequencing confirmed that the samples were hybrids of the two species. Tetradymol (1), the major compound of L. cymbulifera not found in L. tongolensis, was isolated from the hybrid samples collected at both locations, while furanoeremophilan-15-oic acid derivative 4, a compound characteristic to L. tongolensis, was found in the Pachahai hybrid but not in the Desha hybrids. Thus, the chemical consequence of hybridization can be variable. In addition, analysis of L. tongolensis samples at Pachahai indicated that introgression has been a mechanism of generating chemical diversity in the plant. Eleven compounds including three new ones were isolated.

Chemotypes of Ligularia vellerea, its hybrids, and L. melanothyrsa.

Ligularia vellerea and L. melanothyrsa have been found to share chemical characteristics based on geography. In one chemotype (Shangrila type), the major components were either 15-oxygenated furanoeremophilanes or eremophilanolides; and in another (Luguhu type), either 1-angeloyloxyfuranoeremophilanes or corresponding lactones. The two L. vellerea samples were found to have experienced hybridization with either L. cyathiceps or L. kanaitzensis; however, compounds typical of L. vellerea alone were isolated from them.

Chemical and genetic studies on hybrid of Ligularia subspicata and Ligularia cyathiceps collected in Yunnan Province of China.

Two morphologically ambiguous Ligularia samples (samples A and B), and samples with morphology of Ligularia subspicata (sample C), Ligularia lamarum (sample D), or Ligularia cyathiceps (sample E), were collected at Tianchi Pond, Shangrila County, Yunnan Province, China. Analysis of the nucleotide sequence of the internal transcribed spacers (ITSs) in the nuclear ribosomal RNA gene cluster indicated that not only sample B but also sample D was a hybrid of L. cyathiceps and L. lamarum/L. subspicata. Although the morphology of sample A suggested that it was also a hybrid, the ITS sequence of sample A was that of L. cyathiceps. Twenty compounds were isolated from the five samples, and the structures of two new compounds 7 and 14 were determined. Furanoeremophilanes typical of L. lamarum/L. subspicata were detected not only in samples C and D, but also in samples A and B. These results indicate that the ability to produce root chemicals can spread through introgression.

Chemical and genetic similarity and diversity of Ligularia anoleuca and L. fischeri collected in the Hengduan Mountains of China.

The sesquiterpenoid composition in the root and the DNA sequences of evolutionarily neutral regions were studied in Ligularia anoleuca and Ligularia fischeri (Asteraceae) collected in the Sichuan Province of China. LC-MS analysis showed that L. anoleuca populations from different localities had different chemical compositions. However, the isolated compounds were similar to each other, indicating that the differences in chemical composition were not large. The DNA analysis suggested that the two species were indistinguishable. Seventeen furanoeremophilanes and an eremophilane acetal were isolated.

Complex diversity in Ligularia kanaitzensis.

Two samples of Ligularia kanaitzensis collected in the Shizhongshan Mountain region of Yunnan Province, as well as one sample collected in Sichuan Province, were analyzed with regard to root constituents and neutral DNA sequences. The two Shizhongshan samples were found to be different from each other and from other samples analyzed previously, indicating that the intra-specific diversity in the species was highly complex.