Ophiobolin-Type Sesterterpenoids from the Mangrove Endophytic Fungus Aspergillus sp. ZJ-68

Abstract

Eleven new ophiobolin-type sesterterpenoids, asperophiobolins A−K (1−11), along with 12 known analogues (12−23) were isolated from the cultures of the mangrove endophytic fungus Aspergillus sp. ZJ-68. The structures of the new compounds were elucidated through spectroscopic analyses, and their absolute configurations were assigned by a combination of Mo 2 (AcO) 4 -induced electronic circular dichroism spectra and quantum chemical calculations. Asperophiobolins A−D (1−4) represent the first examples possessing a five-membered lactam unit between C-5 and C-21 in ophiobolin derivatives. In the bioactivity assays, compounds 8−10 and 14−17 exhibited inhibitory effects on lipopolysaccharide-induced nitric oxide production in RAW 264.7 macrophage cells with IC 50 values ranging from 9.6 to 25 μM, and compound 8 was found to show comparable inhibition of Mycobacterium tuberculosis protein tyrosine phosphatase B with an IC 50 value of 19 μM.

Novel Antimicrobial Compounds as Ophiobolin-Type Sesterterpenes and Pimarane-Type Diterpene From Bipolaris Species TJ403-B1

“…Further analyses of the HSQC, 1 H-1 H COSY, and HMBC spectral data established an ophiobolin-type sesterterpene nucleus, structurally related to known ophiobolin Q (Cai et al, 2019) with the major differences being listed as follows: (a) the C-21 formyl group in ophiobolin Q was replaced by a hydroxylated methylene group (C-21, δ C 67.0) in 1; and (b) the disappearance of a hydroxylated methylene group (C-18) in ophiobolin Q and the double bond migrated from C-16/C-17 to C-17/C-18 in 1. These conclusions were further supported by the 1 H-1 H COSY correlations (Figure 2) of H-15 (δ H 1.55)/H 2 -16 (δ H 1.71 and 2.20)/H-17 (δ H 5.60)/H-18 (δ H 5.59) and HMBC correlations from H 3 -23 (δ H 0.90) to C-14 (δ C 52.0), C-15 (δ C 33.6), and C-16 (δ C 41.1) and from H 3 -24 (δ H 1.26) to C-18 (δ C 140.6), C-19 (δ C 71.1), and C-25 (δ C 30.1).…”

Chemical analysis and anticancer activity of sesterterpenoid from an endophytic fungus Hypomontagnella monticulosa Zg15SU and its host Zingiber griffithii Baker

“…Asperophioboloins A-K were isolated from a mangrove fungus, Aspergillus sp. ZJ-68 which displayed inhibition against Mycobacterium tuberculosis and LPS-induced nitric oxide production (Cai et al 2019). Bipolarins A-H were isolated from an endophytic fungus in wheat plant, Bipolaris sp.…”

Biological Activities of Some New Secondary Metabolites Isolated from Endophytic Fungi: A Review Study

“…Compound 89 displayed inhibition with an IC 50 value of 19 µM, comparable to the positive control (oleanolic acid, IC 50 = 22 ± 1 µM). Compounds 83, 85, 86 and 90 showed moderate inhibitory activity of MptpB with IC 50 values of 39 ± 2 µM, 42 ± 3 µM, 28 ± 1 µM and 35 ± 1 µM, respectively [38].…”