Aspochalasin H1: A New Cyclic Aspochalasin from Hawaiian Plant-Associated Endophytic Fungus Aspergillus sp. FT1307

Abstract

Aspergillus is one of the most diverse genera, and it is chemically profound and known to produce many biologically active secondary metabolites. In the present study, a new aspochalasin H1 (1), together with nine known compounds (2–10), were isolated from a Hawaiian plant-associated endophytic fungus Aspergillus sp. FT1307. The structures were elucidated using nuclear magnetic resonance (NMR) (1H, 1H-1H COSY, HSQC, HMBC, ROESY and 1D NOE), high-resolution electrospray ionization mass spectroscopy (HRESIMS), and comparisons with the reported literature. The absolute configuration of the new compound was established by electronic circular dichroism (ECD) in combination with NMR calculations. The new compound contains an epoxide moiety and an adjacent trans-diol, which has not been reported before in the aspochalasin family. The antibacterial screening of the isolated compounds was carried out against pathogenic bacteria (Staphylococcus aureus, Methicillin-resistant S. aureus and Bacillus subtilis). The antiproliferative activity of compounds 1–10 was evaluated against human breast cancer cell lines (MCF-7 and T46D) and ovarian cancer cell lines (A2780).

Fungal Endophytes: A Potential Source of Antibacterial Compounds

“…FT1307 associated with plant Heliotropium sp. Compounds 159-162 showed weak activity against Staphylococcus aureus ATCC12600, Bacillus subtilis ATCC6633 and MRSA ATCC43300 with MICs in the range of 40 to 80 µg/mL [84].…”

A validated high-throughput method for assaying rat lungworm (Angiostrongylus cantonensis) motility when challenged with potentially anthelmintic natural products from Hawaiian fungi

“…Our earlier studies have shown that 90 and 100% fractions contain similar, diverse metabolite patterns and biological activities compared to the 50% fraction. Hence, further studies focused on the combined 90 and 100% fractions (Wang et al ., 2020 a , 2020 b ; Yu et al ., 2020 ; Qader et al ., 2021 ; Zaman et al ., 2021 ).…”

“…Cell viability assay of small-scale extracts to prioritize strains for large-scale fermentation The small-scale extracts prepared from isolated fungal strains were tested for the lack of toxicity against one or other of three human cell lines: HT1080 (fibrosarcoma cell line), T46D (breast cancer cell line) and A2780S (ovarian cancer cell line). Nontoxic extracts produced by the respective fungal strains were prioritized for large-scale fermentation (Wang et al, 2020a;Qader et al, 2021;Zaman et al, 2021).…”

Bioactive Compounds Produced by Endophytic Microorganisms Associated with Bryophytes—The “Bryendophytes”

“…Structurally, cytochalasins have a highly substituted perhydroisoindol-1-one moiety, which is fused with a 9- to 15-membered macrocyclic ring. Many cytochalasins exhibit a wide range of biological activities, such as cytotoxic, antimicrobial, and phytotoxic properties [ 48 , 72 , 73 , 74 ]. Indole alkaloids are another group of compounds represented among plant endophytes.…”