Siccanin

Siccanin is an inhibitor of mitochondrial complex II (succinate dehydrogenase; IC₅₀s = 0.87 and 9.3 μM for P. aeruginosa and rat mitochondria, respectively). It inhibits the growth of T. mentagrophytes (IC₅₀ = 0.3 μg/ml) via inhibition of succinate oxidation in the mitochondria. It also inhibits the growth of C. albicans strains with IC₅₀ values ranging from 5-40 and 80-90 μg/ml for aerobic and anaerobic conditions, respectively.

Siccanin is an antifungal and SDHB (IP) inhibitor.

Siccanin is an unusual, fused, phenolic pentacycle first isolated from Helminthosporium siccans and reported in 1962 as a potent antifungal agent. Siccanin inhibits succinate dehydrogenase in the terminal electron transport system. More recent studies note the proximity of the siccanin binding site to the quinone-binding site of the enzyme. Species-selective inhibition by siccanin is unique among succinate dehydrogenase inhibitors and offers a lead for new chemotherapeutics.

ChEBI: Siccanin is an organic heteropentacyclic compound. It has a role as an antifungal drug and a fungal metabolite.

Siccanin was found in the culture broth of Helminthosporium siccans by Sankyo Co. in 1962.

Siccanin shows specific and strong ac tivity against the dermatophytes Trichophyton, Epidermophyton, and Microsporum, but ithas almost no activity against other fungi.

[1] TATSUSHI MOGI. Siccanin rediscovered as a species-selective succinate dehydrogenase inhibitor.[J]. Journal of biochemistry, 2009, 146 3: 383-387. DOI: 10.1093/jb/mvp085
[2] K NOSE  A E. Mode of action of the antibiotic siccanin on intact cells and mitochondria of Trichophyton mentagrophytes.[J]. Journal of Bacteriology, 1971, 105 1: 176-184. DOI: 10.1128/jb.105.1.176-184.1971
[3] MITSUO MATSUKI. Effects of antifungal drugs on proliferation signals in Candida albicans.[J]. Biological & pharmaceutical bulletin, 2006, 29 5: 919-922. DOI: 10.1248/bpb.29.919