31489-31-3Relevant academic research and scientific papers
Inhibition of mushroom tyrosinase activity by orsellinates
Lopes, Thiago Inácio Barros,Coelho, Roberta Gomes,Honda, Neli Kika
, p. 61 - 64 (2018/01/05)
Several applications have been proposed for tyrosinase inhibitors in the pharmaceutical, food bioprocessing, and environmental industries. However, only a few compounds are known to serve as effective tyrosinase inhibitors. This study evaluated the tyrosinase-related activity of resorcinol (1), orcinol (2) lecanoric acid (3), and derivatives of this acid (4-15). Subjected to alcoholysis, lecanoric acid (3), a depside isolated from the lichen Parmotrema tinctorum, produces orsellinic acid (2,4-dihydroxy-6-methylbenzoic acid) (4) and orsellinates (2,4-dihydroxy-6-methyl benzoates) (5-15). At 0.50 mM, methyl (5), ethyl (6), n-propyl (7), tert-butyl (11), and n-cetyl orsellinates (15) acted as tyrosinase activators, whereas n-butyl (8), iso-propyl (9), sec-butyl (10), n-pentyl (12), n-hexyl (13), and n-octyl orsellinates (14) behaved as inhibitors. Tyrosinase inhibition rose with chain elongation-n-butyl (8) n-pentyl (12) n-hexyl (13) n-octyl orsellinates (14)-suggesting that the enzyme site can accept an eight-carbon alkyl chain. A kinetic study of n-octyl orsellinate (14) revealed uncompetitive inhibition of tyrosinase, with an inhibition constant of 0.99 mM.
Assembly of melleolide antibiotics involves a polyketide synthase with cross-coupling activity
Lackner, Gerald,Bohnert, Markus,Wick, Jonas,Hoffmeister, Dirk
, p. 1101 - 1106 (2013/10/01)
Summary Little is known about polyketide biosynthesis in mushrooms (basidiomycota). In this study, we investigated the iterative type I polyketide synthase (PKS) ArmB of the tree pathogen Armillaria mellea, a producer of cytotoxic melleolides (i.e., polyketides esterified with various sesquiterpene alcohols). Heterologously produced ArmB showed orsellinic acid (OA) synthase activity in vitro. Further, we demonstrate cross-coupling activity of ArmB, which forms OA esters with various alcohols. Using a tricyclic Armillaria sesquiterpene alcohol, we reconstituted the biosynthesis of melledonol. Intermolecular transesterification reactions may represent a general mechanism of fungal PKSs to create structural diversity of small molecules. Phylogenetic network construction of thioesterase domains of both basidiomycetes and ascomycetes suggests that the fungal nonreducing PKS family has likely evolved from an ancient OA synthase and has gained versatility by adopting Claisen-like cyclase or transferase activity.
