Transformations of Some Sesquiterpene Lactones by Filamentous Fungi and Cytotoxic Evaluations

Abstract

Biotransformation is an economically and ecologically viable technology which has been used to modify the structures of many classes of biologically active products. Some fungi may be useful for the biotransformation of sesquiterpene lactones (SLs), leading to unusual structural changes that modify their biological activities, and other transformations mimic their biosynthetic pathways, generating evidences for the proposed biogenesis. Eight filamentous fungi were screened for their ability to transform different SLs (1 - 9), and microbial reactions yielded compounds 10 - 17, which in turn have been isolated as natural products, thus mimicking their biosynthesis. Their structures were identified based on NMR and MS spectroscopic analyses. The cytotoxicities of SLs 1, 4, 6, 7 and 9, and their biotransformed produts (10, 14, 15 and 17) against human cancer cell lines U251 (glia), PC3 (prostate), K562 (leukemia), HCT-15 (colon), MCF7 (breast), and SKLU-1 (lung), were determined, confirming that the presence of Michael acceptor is an important feature for the bioactivity.

Biotransformation of Patchouli Alcohol by Cladosporium cladosporioides and the Anti-Influenza Virus Activities of Biotransformation Products

“…The 1 H– 1 H COSY correlations of H 2 -2/H-3/H-4 (Figure ), together with the HMBC correlations (Figure ) from H-3 (δ H 3.16) to C-1 (δ C 77.3), C-2 (δ C 32.7), C-4 (δ C 62.4), and C-5 (δ C 73.9) and from H-4 (δ H 2.90) to C-3 (δ C 53.0), C-5, C-6 (δ C 39.9), and C-10 (δ C 43.5), indicated the O -bearing feature of C-3 and C-4. However, compared with other hydroxyl-substituted methines, C-3 and C-4 appeared in the higher field, which suggested that the epoxy moiety existed between C-3 and C-4. ,− It is also common to produce epoxy moieties during biotransformation. − In addition, the presence of 5-OH was established based on a series of HMBC cross-peaks of H-4, H 2 -6, H 2 -9, and Me-13 with C-5. The NOE correlations of H-3/Me-15 and H-4/Me-15 (Figure ), in combination with the coupling constant of H-3 and H-4 ( J = 4.2 Hz), , supported the α-orientation of the epoxy fragment.…”

New Bromo- and Iodo-Hydroxylactones with Two Methyl Groups Obtained by Biotransformation of Bicyclic Halolactones

“…These are usually lactones containing in their structure, apart from methyl groups, halogen atoms, or double bond. The most common products of such reactions are hydroxyl derivatives of lactones [6][7][8][9][10][11][12].…”