Fungal Metabolites. VIII: Structures of New Sesquiterpenes From Lactarius Scrobiculatus

Abstract

GIORGIO MELLERIO', GIOI-ASSI T-IDARI* and P.io~.i I-ITA-FISSI~ * ?Isfituto di Chiniica Organicci--ni;,ersita degli Studi-lCale W r a n i e l l i 10-27100 PaLmia (Italy) 3Centro del C-TR p e r lo Studio delle Sostanre Organiche .\htiirali-Politecnico-Piarra L e o m r d o do Ti'nci 32-20133 X i l a n o (Italjj ;iBsTR.icT.-From lots of Lncfarrzts scrobzciilnfus extracted in different B-ays, in addition to ethyl linoleate and cerevisterol, nine lactarane sesquiterpenes have been isolated. The main compounds are furanosesquiterpenes, namely: furoscrobiculins -4-D (2, S-i), furanethers 13 and 4) and the already known lactaral (l), and furandiol 19a). Furthermore a new sesquiterpene lactone with the CO group in 13, lactaroscrobiculide B (8), has been isolated. The structures were elucidated mainly by spectroscopic methods and by some chemical transformations. Stereochemistry of most sesquiterpenes has been determined.Recently (1-3) we isolated from Lactariids scrobiciilatzks some sesquiterpenes 11-ith the lactarane skeleton which is peculiar to most of the knon-n Russulaceae metabolites (4-1i). At present the only mushrooms of this family containing sesquiterpenes with a completely different skeleton are L. deliciosus (1s) (guaianes) and L. uzidzis (19) (drimanes).Sou-11-e report the structures of ne!\ lactarane sesquiterpenes which were isolated from a nen-lot of L. scrobiciilatus extracted in a different way than in the previous \I ork (2. 3). DISCCSSIOSL. scrobiczilatus is easily distinguished not only by the morphological aspects (yellow color, big size. wrobiculated stem, pungent taste, etc.), but also by the secreted milky juice, n-hich, for some reason not yet understood, turns quickly from n hite to yelloJv when it appears at the surface of the fruit-body. This color change could indicate enzymatic degradation reactions : therefore, in order to prevent and to check possible alterations in the sesquiterpene composition. n-e carried out extraction in three different nays:The frozen material \vas then minced under its solvent and. after being removed by filtration. it was homogenized in ethanol and ice to extract the more polar compounds.b) The freshly collected mushrooms nere cut and put in acetone. The material \vas norked up in a dry-box under a S? stream as in a). In this case, the color change in the juice seemed to be slon-er but n-as still noticeable.a) The fruit-bodies nere frozen in drj ice and acetone.c) The fruit-bodiei n ere cut without any precaution.

Chemical Constituents from the Rhizome ofAcorus calamusL.

“…The chemical shift of C-4, C-6, C-10 suggested that these carbons were oxygen substituted. The 1 H NMR spectrum of 2 showed the presence of two secondary methyl groups at δ 0.97 (d, J = 6.6 Hz), 1.02 (d, J = 6.6 Hz), two tertiary methyl groups at δ 1.11 (s), 1.20 (s), and an ethoxy group at 1.11 (t, J = 7.0 Hz), δ 3.27 (1H, dq, J = 9.0, 7.0 Hz), 3.40 (1H, dq, J = 9.0, 7.0 Hz) [13], which explained the presence of two carbon atoms extra to a bicyclic sesquiterpene skeleton.…”

Non-peptide secondary metabolites from poisonous mushrooms: overview of chemistry, bioactivity, and biosynthesis

“…178 2.5.1.3 Lactaranes. Diverse types of lactarane sesquiterpenes have been identied from the Russulaceae family of fungi (genera Lactarius and Russula), [182][183][184][185][186][187][188][189] particularly from the poisonous mushroom Lactarius scrobiculatus, which has an intensely pungent taste presumed to be responsible for the high toxicity of the mushroom. Among different types, sesquiterpene lactones account for the majority of lactaranetype lactones.…”

Pseudo-Natural Products, Some Artefacts Formed during the Isolation of Terpenoids

“…The condensation product 34 has been detected when acetone has been used in the extraction. 41,51 In studies on the carotenoids from the bacterium Rhodopseudomonas viridis, the condensation product of lycopene 20-aldehyde with acetone was also detected 52 as an artefact when acetone was used during the extraction. The purification of the diterpenoid quinones from Plectranthus grandidentus using acetone afforded 53 some unusual artefacts including 35 involving the addition of acetone.…”