Isopimaric acid
Names
IUPAC name
(13S)-Pimara-7,15-dien-18-oic acid
Systematic IUPAC name
(1R,4aR,4bS,7S,10aR)-7-Ethenyl-1,4a,7-trimethyl-1,2,3,4,4a,4b,5,6,7,8,10,10a-dodecahydrophenanthrene-1-carboxylic acid
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.163.144 Edit this at Wikidata
KEGG
UNII
  • InChI=1S/C20H30O2/c1-5-18(2)12-9-15-14(13-18)7-8-16-19(15,3)10-6-11-20(16,4)17(21)22/h5,7,15-16H,1,6,8-13H2,2-4H3,(H,21,22)/t15-,16+,18-,19+,20+/m0/s1 ☒N
    Key: MXYATHGRPJZBNA-KRFUXDQASA-N ☒N
  • InChI=1/C20H30O2/c1-5-18(2)12-9-15-14(13-18)7-8-16-19(15,3)10-6-11-20(16,4)17(21)22/h5,7,15-16H,1,6,8-13H2,2-4H3,(H,21,22)/t15-,16+,18-,19+,20+/m0/s1
    Key: MXYATHGRPJZBNA-KRFUXDQABR
  • [H][C@]12[C@](C)(C(O)=O)CCC[C@]1(C)[C@]3([H])C(C[C@](C=C)(C)CC3)=CC2
Properties
C20H30O2
Molar mass 302.458 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Isopimaric acid (IPA) is a toxin which acts as a large conductance Ca2+-activated K+ channel (BK channel) opener.

Sources

IPA originates from many sorts of trees, especially conifers.[1]

Chemistry

IPA is one of the members of the resin acid group and it is a tricyclic diterpene.[1]

Target

IPA acts on the large-conductance calcium activated K+ channels (BK channels).[2][3]

Mode of action

BK channels are formed by α subunits and accessory β subunits arranged in tetramers. The α subunit forms the ion conduction pore and the β subunit contributes to channel gating. IPA interaction with the BK channel enhances Ca2+ and / or voltage sensitivity of the α subunit of BK channels without affecting the channel conductance. In this state BK channels can still be inhibited by one of their inhibitors, like charybdotoxin (CTX).[2][3] Opening of the BK channel leads to an increased K+-efflux which hyperpolarizes the resting membrane potential, reducing the excitability of the cell in which the BK-channel is expressed.

Toxicity

Studies on rainbow trout hepatocytes have shown that IPA increases intracellular calcium release, leading to a disturbance in the calcium homeostasis. This could be important in the possible toxicity of the toxin.

See also

Notes

  1. ^ a b Wilson, AE; Moore, ER; Mohn, WW (1996). "Isolation and characterization of isopimaric acid-degrading bacteria from a sequencing batch reactor". Applied and Environmental Microbiology. 62 (9): 3146–51. Bibcode:1996ApEnM..62.3146W. doi:10.1128/aem.62.9.3146-3151.1996. PMC 168108. PMID 8795202.
  2. ^ a b Kaczorowski, GJ; Knaus, HG; Leonard, RJ; McManus, OB; Garcia, ML (1996). "High-conductance calcium-activated potassium channels; structure, pharmacology, and function". Journal of Bioenergetics and Biomembranes. 28 (3): 255–67. doi:10.1007/bf02110699. PMID 8807400. S2CID 25857254.
  3. ^ a b Imaizumi, Y; Sakamoto, K; Yamada, A; Hotta, A; Ohya, S; Muraki, K; Uchiyama, M; Ohwada, T (2002). "Molecular basis of pimarane compounds as novel activators of large-conductance Ca(2+)-activated K(+) channel alpha-subunit". Molecular Pharmacology. 62 (4): 836–46. doi:10.1124/mol.62.4.836. PMID 12237330.

References

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