229
6 Biological Activities
Several studies on the biological activities of compounds isolated from Ligularia
species are described below in this contribution.
The cytotoxicity of dehydrofukinone (5), and of compounds 20, 23, 340, 341,
342, and 358, was evaluated using several cancer cell lines, including HeLa, HL-60,
NCI-H460, and Raji cells [41]. Compounds 341 and 342 showed significant inhibitory activities against HL-60 (IC 50 2.8, 5.8 μM) and Raji (IC 50 2.9, 4.2 μM) cells.
Spiciformisin b (888), isolated from L. fischeri, demonstrated cytotoxicity against
HL-60 cells, while spiciformisin a (887) exhibited no discernible cytotoxicity [187].
The allelopathic effects of compounds 97, 98, and 343 have been assessed using
germination and seedling growth assays using lettuce [344]. Compounds 97 and
343 inhibited the growth of both hypocotyls and radicles; 97 was much more potent
than 343 in this regard.
All 12 compounds isolated from L. thomsonii (Table 47; 903–905, 921– 923,
926, 1015–1018, and 1035) were tested for antioxidant activity using a
1,1- diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay [258]. Of these,
caffeic acid (903), 895, and 979 showed strong activities (IC 50 values of 19.6, 23.3,
and 8.9 μM).
Anti-complimentary activities have been measured for compounds 727, 728,
734, 749, 750, 751, and 754, isolated from L. knorringiana [235]. Compound 757
was found to be about one fifth as active (CH 50 0.33 mM), when compared with the
standard used, heparin (CH 50 0.06 mM).
Three compounds, cacalol (316), farfugin B (335), and 336, isolated from
L. virgaurea (Table 3), have been found to inhibit [
3
H]-nitrendipine binding to
pig heart membranes (IC 50 3.98 × 10
−5
, 2.00 × 10
−5
, 2.75 × 10
−5
M, respectively).
Farfugin B (335) and 336 inhibited the contraction of arteries induced by high K
+
ion levels and blocked Ca
2+
ion influx by occupying the binding sites of dihydropyridine [168].
A series of 29 oxyprenylated and azoprenylated phenylpropanoids, comprised by
nelumol A (989), nelumal A (993), 979, 980, and related compounds, was synthesized and tested in transfected cultured HepG2 cells as farnesoid X receptor (FXR)
agonists [345]. Nelumol A (989) and nelumal A (993) showed potent activity.
Nelumal A (993) was regarded as a novel lead compound in the search for FXR
agonists. However, both compound 989 and 993 were found to be cytotoxic to KB
cells (IC 50 3.0 × 10
−6
, 2.6 × 10
−6
M, respectively) [270, 346].
Synthetic compounds with a hydrindane skeleton similar to noreremophilanes
have been tested for their antiangiogenic effects on developing zebrafish embryos as
well as for tumor-inducing angiogenesis activity in a zebrafish xenograft model
[334]. Among these compounds, noreremophilanes 1158, 1160, and 1161 showed
potent effects (Sect. 5.16). Compound 1161 was the most active angiogenesis
inhibitor.
Chemical Constituents of Ligularia Species (Asteraceae) and Their Diversity…
6 Biological Activities
Several studies on the biological activities of compounds isolated from Ligularia
species are described below in this contribution.
The cytotoxicity of dehydrofukinone (5), and of compounds 20, 23, 340, 341,
342, and 358, was evaluated using several cancer cell lines, including HeLa, HL-60,
NCI-H460, and Raji cells [41]. Compounds 341 and 342 showed significant inhibitory activities against HL-60 (IC 50 2.8, 5.8 μM) and Raji (IC 50 2.9, 4.2 μM) cells.
Spiciformisin b (888), isolated from L. fischeri, demonstrated cytotoxicity against
HL-60 cells, while spiciformisin a (887) exhibited no discernible cytotoxicity [187].
The allelopathic effects of compounds 97, 98, and 343 have been assessed using
germination and seedling growth assays using lettuce [344]. Compounds 97 and
343 inhibited the growth of both hypocotyls and radicles; 97 was much more potent
than 343 in this regard.
All 12 compounds isolated from L. thomsonii (Table 47; 903–905, 921– 923,
926, 1015–1018, and 1035) were tested for antioxidant activity using a
1,1- diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay [258]. Of these,
caffeic acid (903), 895, and 979 showed strong activities (IC 50 values of 19.6, 23.3,
and 8.9 μM).
Anti-complimentary activities have been measured for compounds 727, 728,
734, 749, 750, 751, and 754, isolated from L. knorringiana [235]. Compound 757
was found to be about one fifth as active (CH 50 0.33 mM), when compared with the
standard used, heparin (CH 50 0.06 mM).
Three compounds, cacalol (316), farfugin B (335), and 336, isolated from
L. virgaurea (Table 3), have been found to inhibit [
3
H]-nitrendipine binding to
pig heart membranes (IC 50 3.98 × 10
−5
, 2.00 × 10
−5
, 2.75 × 10
−5
M, respectively).
Farfugin B (335) and 336 inhibited the contraction of arteries induced by high K
+
ion levels and blocked Ca
2+
ion influx by occupying the binding sites of dihydropyridine [168].
A series of 29 oxyprenylated and azoprenylated phenylpropanoids, comprised by
nelumol A (989), nelumal A (993), 979, 980, and related compounds, was synthesized and tested in transfected cultured HepG2 cells as farnesoid X receptor (FXR)
agonists [345]. Nelumol A (989) and nelumal A (993) showed potent activity.
Nelumal A (993) was regarded as a novel lead compound in the search for FXR
agonists. However, both compound 989 and 993 were found to be cytotoxic to KB
cells (IC 50 3.0 × 10
−6
, 2.6 × 10
−6
M, respectively) [270, 346].
Synthetic compounds with a hydrindane skeleton similar to noreremophilanes
have been tested for their antiangiogenic effects on developing zebrafish embryos as
well as for tumor-inducing angiogenesis activity in a zebrafish xenograft model
[334]. Among these compounds, noreremophilanes 1158, 1160, and 1161 showed
potent effects (Sect. 5.16). Compound 1161 was the most active angiogenesis
inhibitor.
Chemical Constituents of Ligularia Species (Asteraceae) and Their Diversity…