Diisoprenyl-cyclohexene/ane-Type Meroterpenoids from Biscogniauxia sp. and Their Anti-inflammatory Activities

Abstract

A secondary metabolites investigation on Biscogniauxia sp. 71-10-1-1 was carried out, which led to the obtention of nine new diisoprenyl-cyclohexene/ane-type meroterpenoids (1–9) and two new isoprenylbenzoic acid-type meroterpeniods (10–11). The structures of these isolates were established on the basis of multispectroscopic analyses, ECD, and 13C chemical shifts calculations, and single-crystal X-ray diffraction. Among them, biscognin A (1) is the first diisoprenyl-cyclohexene-type meroterpenoid with a unique 2-isopropyl-6′-methyloctahydro-1′H-spiro­[cyclopropane-1,2′-naphthalene] skeleton. Biscognienyne F (5) is the first diisoprenyl-cyclohexene-type meroterpenoid with a cyclic carbonate. The anti-inflammatory assays of the majority of compounds were evaluated, which exhibited that compounds 3 and 5 can obviously inhibit pro-inflammatory cytokines TNF-α and IL-6 productions. This is the first report for diisoprenyl-cyclohexene-type meroterpenoids with anti-inflammatory activity. Moreover, the possible biogenetic pathways of the majority of compounds (1–5) are proposed.

Shikimate-Derived Meroterpenoids from the Ascidian-Derived Fungus Amphichorda felina SYSU-MS7908 and Their Anti-Glioma Activity

“…These skeletons include 14 monocyclics (cyclohexene/ ane, e.g., iso-A82775C 40 ), 62 bicyclics {benzofuran (6/5, e.g., truncateols D−L 43 ), chromen (6/6, e.g., oxirapentyns F−J 31 ), naphthalene (6/6, biscognin B 44 ), and spiro[cyclohexene/anecyclopropane] (6/3, pestalotriols A and B 45 )}, 18 tricyclics {furo[2,3-g/h]chromene (5/6/6, e.g. pestalotheols A, B, and D 46 ), pyrano[2,3-g]chromene (6/6/6, oxirapentyn K 31 ), chromene−cyclocarbonate fused (6/6/5, biscognienyne F and felinoid A 30,44 ), cyclopropa[c]benzofuran (3/5/6, biscognienyne E 44 ), spiro[chromene-cyclopropane] (6/6/3, pestaloficiols B−E 47 ), and spiro[cyclopropane-naphthalene] (3/6/6, biscognin A 44 )}, and one tetracyclic {cyclopropa [3,4]furo[2,3h]chromene, 3/5/6/6, pestaloficiol A 47 }. In this study, four new members (1−4) with two distinct types of 6/6/6 tricyclic systems were obtained, further enriching the diversity of 6/6/6 tricyclic systems (only one reported compound, 5, oxirapentyn To investigate the structure−activity relationship (SAR) of the anti-glioma activity, four new derivatives (10−13) were semisynthesized by making simple structural modifications (oxidation or hydrolysis) of the natural product oxirapentyn B (6) or oxirapentyn A (7) isolated from A. felina SYSU-MS7908 (Scheme 1).…”

Isolation of new compounds related to xyloketals biosynthesis implies an alternative pathway for furan-fused-chromene formation

“…During our ongoing search for bioactive natural products from fungi, 20–23 we isolated four new analogues of xyloketal B, simpliketals A–D ( 1–4 ), along with two other new compounds simplilactones A and B ( 5 and 6 ) from Simplicillium sp. AHK071-01 (Fig.…”

Two New Diterpenoids from Biscogniauxia sp. and Their Activities

“…belongs to the Xylariaceae family, growing on the bark of trees and shrubs, preferably on dead or dying branches. Since the first report on the secondary metabolites in 2005 (Evidente et al, 2005), nearly 50 secondary metabolites have been reported, including azaphilones (Cheng et al, 2012), meroterpenoids (Zhao et al, 2017;Zhao et al, 2019;Zhao et al, 2021), sesquiterpenes (Amand et al, 2012), aromatics (Evidente et al, 2005;Cheng et al, 2012;Cheng et al, 2011), isocoumarins (Evidente et al, 2005;Cheng et al, 2012;Amand et al, 2012;Sritharan et al, 2019), amides (Cheng et al, 2012;Cheng et al, 2011), and cyclopeptides (Wu et al, 2016), which exhibit a widespread of bioactivities, including antimicrobial (Cheng et al, 2012), enzyme inhibitory (Wu et al, 2016), inhibitory of seed germination (Evidente et al, 2005), antiinflammatory (Zhao et al, 2021), or short-term memory enhancement in AD flies activities (Zhao et al, 2017).…”

“…In our previous chemical investigation of a fungal strain of Biscogniauxia sp. (No.71-10-1-1), structurally diverse active meroterpenoids (diisoprenyl-cyclohexene/ane-type) and their dimers with new skeleton were identified (Zhao et al, 2017;Zhao et al, 2019;Zhao et al, 2021), which showed that this strain can produce natural products with rich chemical diversity. Further chemical investigation on this fungal strain was carried out, which led to the isolation of two new diterpenoids, including a seco-isopimarane type (1) and an abietane type (2).…”