185
eremophilanes and furanoeremophilanes [23, 24, 34, 38, 115, 127]. From some
samples (L. lamarum sample 8, L. subspicata samples 1–3), only bicyclic eremophilanes were purified. For the other samples, it was not possible to classify the
samples into chemotypes, since they could not be differentiated readily. As bicyclic eremophilanes, compounds 1, 2, 3, 4, 5, 8, 14, 20, 24, 25, 28 (kanaitzensol),
33, 54, 56, 60, 62, 63, and 64 were isolated together with their derivatives 98,
125, 132, 340, and 341. Among these, compounds 4, 60, and 62 were obtained as
major components. For the furanoeremophilanes, both the 10H derivatives, 161,
162, 163, 164, 165, 166, 167, 168, and 169, including also subspicatins A (171),
B (172), C (173), and G (174), and the 10-OH derivatives 225, 226, 227, 228, 229,
230, 231, and 232 were isolated. Related eremophilanolides were also present,
inclusive of 344, 346, 356, 359, eremopetasitenin A4 (516), subspicatins E (518),
D (521), and F (540), eremofarfugin C (538), 557, subspicatolide (559), and subspicatolide acetate (560) (10H type) and 396, 399, 400, 401, 524, and 555 (10-OH
type). Compound 555 was assigned as a mixture of two orthoacetates. The major
furanoeremophilanes were 161, 171, and 172. Subspicatins A (171) and B (172)
are characteristic components of the furanoeremophilane- producing type of
L. lamarum and L. subspicata. Other isolated compounds were 6-hydroxyeuryopsin (248), 314, secobakkane A (151), seco-eremophilane 153, bakkenolide A
(629), its derivative 634, (−)-α-bisabolol (648), lupeol (828), and phenylpropanoids 932 and 979. The relative configuration of the epoxide 25 was determined
by X-ray crystallographic analysis (Sect. 3.26). Secobakkane A (151) has a rare
6,7-seco-bakkane skeleton and may be regarded as a rearranged seco- eremophilane.
The structure of ethyl ferulate (932) in the original report [24] must be corrected
as depicted in the present contribution.
3.30 Ligularia lankongensis (Franchet) Handel-Mazzetti
This is a bisabolane-producing species. Eight samples (samples 1–8) were collected in northwestern Yunnan Province, China, and one (sample 9) from southern
Sichuan Province (Plate 24, Table 38). Nine highly oxygenated bisabolanes (657,
675, 676, 678, 679, 682, 684, 697, and 708) were isolated (see Sect. 5.18 for the
structures of 657 and 682) [226, 228]. Among these, compound 676 was isolated
from all samples. Differences in chemical composition and in their ITS sequences
were small between these samples. Interestingly, compound 678, the major component of the Sichuan sample (sample 9), was not isolated from the Yunnan samples. Tan et al. isolated the 3,4-diol derivatives 694 and 695 from another Yunnan
sample [231].
Chemical Constituents of Ligularia Species (Asteraceae) and Their Diversity…
eremophilanes and furanoeremophilanes [23, 24, 34, 38, 115, 127]. From some
samples (L. lamarum sample 8, L. subspicata samples 1–3), only bicyclic eremophilanes were purified. For the other samples, it was not possible to classify the
samples into chemotypes, since they could not be differentiated readily. As bicyclic eremophilanes, compounds 1, 2, 3, 4, 5, 8, 14, 20, 24, 25, 28 (kanaitzensol),
33, 54, 56, 60, 62, 63, and 64 were isolated together with their derivatives 98,
125, 132, 340, and 341. Among these, compounds 4, 60, and 62 were obtained as
major components. For the furanoeremophilanes, both the 10H derivatives, 161,
162, 163, 164, 165, 166, 167, 168, and 169, including also subspicatins A (171),
B (172), C (173), and G (174), and the 10-OH derivatives 225, 226, 227, 228, 229,
230, 231, and 232 were isolated. Related eremophilanolides were also present,
inclusive of 344, 346, 356, 359, eremopetasitenin A4 (516), subspicatins E (518),
D (521), and F (540), eremofarfugin C (538), 557, subspicatolide (559), and subspicatolide acetate (560) (10H type) and 396, 399, 400, 401, 524, and 555 (10-OH
type). Compound 555 was assigned as a mixture of two orthoacetates. The major
furanoeremophilanes were 161, 171, and 172. Subspicatins A (171) and B (172)
are characteristic components of the furanoeremophilane- producing type of
L. lamarum and L. subspicata. Other isolated compounds were 6-hydroxyeuryopsin (248), 314, secobakkane A (151), seco-eremophilane 153, bakkenolide A
(629), its derivative 634, (−)-α-bisabolol (648), lupeol (828), and phenylpropanoids 932 and 979. The relative configuration of the epoxide 25 was determined
by X-ray crystallographic analysis (Sect. 3.26). Secobakkane A (151) has a rare
6,7-seco-bakkane skeleton and may be regarded as a rearranged seco- eremophilane.
The structure of ethyl ferulate (932) in the original report [24] must be corrected
as depicted in the present contribution.
3.30 Ligularia lankongensis (Franchet) Handel-Mazzetti
This is a bisabolane-producing species. Eight samples (samples 1–8) were collected in northwestern Yunnan Province, China, and one (sample 9) from southern
Sichuan Province (Plate 24, Table 38). Nine highly oxygenated bisabolanes (657,
675, 676, 678, 679, 682, 684, 697, and 708) were isolated (see Sect. 5.18 for the
structures of 657 and 682) [226, 228]. Among these, compound 676 was isolated
from all samples. Differences in chemical composition and in their ITS sequences
were small between these samples. Interestingly, compound 678, the major component of the Sichuan sample (sample 9), was not isolated from the Yunnan samples. Tan et al. isolated the 3,4-diol derivatives 694 and 695 from another Yunnan
sample [231].
Chemical Constituents of Ligularia Species (Asteraceae) and Their Diversity…