Clavariadelphus truncatus (Quél.) Donk, the flat-topped coral.
Clavaria truncata Quél.
Clavaria truncata Lovejoy
Clavariadelphus borealis V.L. Wells & Kempton
Trombetta pistillaris (Fr.) Kuntze
Truncated club coral
Fruiting body: 6-15 cm tall, 2.0-8 cm wide; club-shaped; tip rounded at first, but soon flattened and sometimes depressed in age, with a rounded, uplifted margin; surface dry, smooth at first, developing irregular vertical wrinkles or grooves; light orange-yellow to orange or yellowish-brown.
Flesh: white, thin, hollow at top.
Spore print: yellowish.
Spores: 9-12 x 5-7 µm, ellipsoid, smooth, hyaline, nonamyloid.
Edibility: edible, with a distinctive bitter-sweet taste.
Habitat: solitary, gregarious, or in small clusters on soil in coniferous woods; late summer to autumn.
Chemical reactions: flesh turns green in FeSO4.
Farnesyl-protein transferase (FPTase) is an enzyme that catalyses the transfer of the isoprenoid farnesyl to various cellular proteins, a process that is essential to establishing the proper cellular location and activity of the modified proteins. Included among these modified proteins is Ras, a protein that when farnesylated has tumor-causing properties. Inhibition of FPTase activity is known to reduce tumor development in mice, suggesting that FPTase is a viable therapeutic target in human cancers, especially in leukemias and pancreatic and colon carcinomas, where mutated ras-oncogenes are often found. Research has shown that the triterpenoid clavaric acid, a fungal metabolite found in C. truncatus, inhibits FTPase, with an IC50 = 1.3 µM (Jayasuriya et al., 1998; Lingham et al., 1998).
Clavaric acid, the common name for 24,25-dihydroxy-2-(3-hydroxy-3-methylglutaryl) lanostan-3-one.
Using the disk diffusion and microdilution methods, the antimicrobial activity of C. truncatus was evaluated (Yamac and Bilgili, 2006). Aqueous and organic extracts of the club mushroom had a broad antibacterial spectrum, showing weak activity against the Gram-negative bacteria Escherichia coli, Enterobacter aerogenes and Salmonella typhimurium. Both extracts were also antibacterial towards Staphylococcus aureus and Bacillus subtilis; the spectrum and levels of antimicrobial activity were similar to that of the positive control, ceftriaxone. The antibiotic activity was not sensitive to heat treatment (i.e. heating at 60°C for 30 min or 100°C for 5 min).
Jayasuriya H, Silverman KC, Zink DL, Jenkins RG, Sanchez M, Pelaez F, Vilella D, Lingham RB, Singh SB.
Clavaric acid: A triterpenoid inhibitor of farnesyl-protein transferase from Clavariadelphus truncatus.
J Nat Prod. 1998 61(12):1568-70.
Lingham RB, Silverman KC, Jayasuriya H, Kim BM, Amo SE, Wilson FR, Rew DJ, Schaber MD, Bergstrom JD, Koblan KS, Graham SL, Kohl NE, Gibbs JB, Singh SB.
Clavaric acid and steroidal analogues as ras- and FPP-directed inhibitors of human farnesyl-protein transferase.
J Med Chem. 1998 41(23):4492-501.