Bioactive Compounds from Medicinal Plants in Myanmar
203
(377) [431], coronarin D methyl ether (378) [418], and (E)-labda-8(17),12,14-trien15,16-olide (379) [423]) (Fig. 72). Among these isolated labdane diterpenoids,
compounds 364–366 and 376–379 were somewhat active as cytotoxic agents against
the cell lines in which they were evaluated, displaying IC 50 values ranging from 19.7
to 96.1 μM. Interestingly, (E)-14-hydroxy-15-norlabda-8(17),12-dien-16-al (373)
inhibited selectively the growth of HeLa, PANC-1, and PSN-1 cells, with IC 50 values
of 5.88, 1.00, and 3.98 μM, respectively, at potency levels comparable to those of
the positive control, 5-fluorouracil (IC 50 values of 8.34, 11.7, and 7.11 μM, respectively). Compound 373 has been isolated from the rhizomes of Zingiber ottensii
[423] and the roots of Aframomum melegueta [432]. In contrast, compounds 363 and
368 were not active at all at the highest treatment dose used (100 μM) against all
of the cancer cell lines employed in the investigation. Structure-activity relationship
conclusions among the labdane diterpenoids 371–376 against PANC-1 and PSN-1
R
H
377 (coronarin D ethyl ether) R = Et
378 (coronarin D methyl ether) R = Me
379 ((E)-labda-8(17),12,14trien-15,16-olide)
371 ((E)-15,15-diethoxylabda-8(17),12dien-16-al ) R = CH(OEt) 2
372 ((E)-labda-8(17),12-dien-15,16-dial)
R = CHO
373 ((E)-14-hydroxy-15norlabda-8(17),12-dien-16-al ) R = OH
374 (zarumin A) R = COOH
375 (methyl (12E)-16-oxolabda-8(17),12dien-15-oate ) R = COOMe
376 ((E)-labda-8(17),12-dien-15-ol-16-al)
R = CH 2 OH
O
O
O
O
RO
O
O
R
367 ((E)-15,16-bisnorlabda-8(17),11dien-13-one) R = Me
368 ((E)-14,15,16-trinorlabda-8(17),11dien-13-al) R = H
369 ((E)-14,15,16-trinorlabda-8(17),11dien-13-oic acid) R = OH
H
O
O
O
370 (16-oxolabda-8(17),12-dien15,11-olide)
Fig. 72 Structures of the known labdane diterpenoids 367–379 isolated from a methanol extract
of C. amada rhizomes grown in Myanmar
203
(377) [431], coronarin D methyl ether (378) [418], and (E)-labda-8(17),12,14-trien15,16-olide (379) [423]) (Fig. 72). Among these isolated labdane diterpenoids,
compounds 364–366 and 376–379 were somewhat active as cytotoxic agents against
the cell lines in which they were evaluated, displaying IC 50 values ranging from 19.7
to 96.1 μM. Interestingly, (E)-14-hydroxy-15-norlabda-8(17),12-dien-16-al (373)
inhibited selectively the growth of HeLa, PANC-1, and PSN-1 cells, with IC 50 values
of 5.88, 1.00, and 3.98 μM, respectively, at potency levels comparable to those of
the positive control, 5-fluorouracil (IC 50 values of 8.34, 11.7, and 7.11 μM, respectively). Compound 373 has been isolated from the rhizomes of Zingiber ottensii
[423] and the roots of Aframomum melegueta [432]. In contrast, compounds 363 and
368 were not active at all at the highest treatment dose used (100 μM) against all
of the cancer cell lines employed in the investigation. Structure-activity relationship
conclusions among the labdane diterpenoids 371–376 against PANC-1 and PSN-1
R
H
377 (coronarin D ethyl ether) R = Et
378 (coronarin D methyl ether) R = Me
379 ((E)-labda-8(17),12,14trien-15,16-olide)
371 ((E)-15,15-diethoxylabda-8(17),12dien-16-al ) R = CH(OEt) 2
372 ((E)-labda-8(17),12-dien-15,16-dial)
R = CHO
373 ((E)-14-hydroxy-15norlabda-8(17),12-dien-16-al ) R = OH
374 (zarumin A) R = COOH
375 (methyl (12E)-16-oxolabda-8(17),12dien-15-oate ) R = COOMe
376 ((E)-labda-8(17),12-dien-15-ol-16-al)
R = CH 2 OH
O
O
O
O
RO
O
O
R
367 ((E)-15,16-bisnorlabda-8(17),11dien-13-one) R = Me
368 ((E)-14,15,16-trinorlabda-8(17),11dien-13-al) R = H
369 ((E)-14,15,16-trinorlabda-8(17),11dien-13-oic acid) R = OH
H
O
O
O
370 (16-oxolabda-8(17),12-dien15,11-olide)
Fig. 72 Structures of the known labdane diterpenoids 367–379 isolated from a methanol extract
of C. amada rhizomes grown in Myanmar