Chemical investigation of the fermentation extract of the coral-associated fungus Aspergillus sp. ITBBc1 led to the discovery of five unreported p-terphenyl derivatives, sanshamycins A–E (1–5), together with five previously described analogues, terphenyllin (6), 3-hydroxyterphenyllin (7), candidusin A (8), 4,5-dimethoxycandidusin A (9), and candidusin C (10). Their structures were elucidated by HRESIMS data and NMR spectroscopic analysis. Compound 1 represents the first example of p-terphenyls with an aldehyde substitution on the benzene ring. Compounds 2–4 feature varying methoxyl and isopentenyl substitutions, while compound 5 features a five-membered lactone linked to a biphenyl. These findings expand the chemical diversity of the family of p-terphenyl natural products. Compounds 1–6 and 9 were evaluated for their inhibitory activity against type 4 phosphodiesterase (PDE4), which is a fascinating drug target for treatment of inflammatory, respiratory, and neurological diseases. Compound 3 was the most potent and exhibited PDE4D inhibitory activity with an IC₅₀ value of 5.543 µM.

Drought is a major environmental factor limiting crop productivity. Photosynthesis is very sensitive to drought. Basic helix-loop-helix (bHLH) transcription factors (TFs) are important in response to abiotic stress. However, their functions remain unclear. Herein, we generated CgbHLH001 (a TF gene from halophyte Chenopodium glaucum)-overexpressed (OE) and ZmbHLH-RNA interference (Ri) maize lines to investigate their photosynthesis-associated indexes under drought conditions. The photosynthetic capacity was increased in OE lines under drought stress compared with that in non-transgenic (NT) and Ri plants. A greater root biomass, higher root/shoot ratio, and a relatively lower leaf area reduction ratio was also observed in OE plants. Compared to NT and Ri plants, OE lines showed a higher chlorophyll content and net photosynthetic rate and better chlorophyll fluorescence parameters under drought conditions. Fructose and glucose contents were also significantly elevated in OE lines. Moreover, under stressful conditions, CgbHLH001 overexpression increased the expression of genes related to photosynthesis. Transcriptomic data showed that many differentially expressed genes were enriched in the photosynthetic system in OE and Ri plants under drought conditions and were prone to being upregulated under drought stress in OE plants. Therefore, our results suggest that CgbHLH001 improves photosynthetic efficiency under drought stress and confers drought tolerance in maize seedlings.

A marine-derived fungal strain, Aspergillus sp. ITBBc1, was isolated from coral collected from the South China Sea in Hainan province. Intensive chemical investigation of the fermentation extract of this strain afforded four new secondary metabolites (1–4), named megastigmanones A–C and prenylterphenyllin H, along with four known compounds (5–8). Their structures were elucidated by extensive spectroscopic analysis including one-and two-dimensional (1D and 2D) NMR spectroscopy and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS). The modified Mosher’s method was undertaken to determine the absolute configurations of new compounds. The phytotoxic activity test showed that compounds 6–8 exhibited significant antagonistic activity against the germination of Triticum aestivum L. and Oryza sativa L. seeds with a dose-dependent relationship.

Eight compounds, including two new compounds, xishaxanthone A (1) and xishaxanthone B (2), and six known compounds (3–8), were isolated from the marine-derived fungus Penicillium sp. F28 and structurally characterized. Xishaxanthone A (1) is a new xanthone derivative which possesses a 1,7-dihydroxanthone skeleton with a methyl carboxylate group at C-8, a substitution pattern rarely encountered among xanthone natural products. The structure was determined by a combination of techniques including HR-ESI-MS (High-Resolution Electrospray Ionization Mass Spectrometry), NMR (Nuclear Magnetic Resonance), and ECD (Electronic Circular Dichroism) calculations. Furthermore, a hypothetical biosynthetic pathway for compound 1 is proposed.