Three new dihydroisocoumarin penicimarins G–I (1–3), together with one known dihydroisocoumarin (4) and three known meroterpenoids (5–7), were obtained from a fungus Penicillium citrinum isolated from the mangrove Bruguiera sexangula var. rhynchopetala collected in the South China Sea. Their structures were elucidated by the detailed analysis of spectroscopic data. The absolute configuration of 1 was determined by the X-ray diffraction analysis using Cu Kα radiation. The absolute configurations of 2 and 3 were determined by comparison of their circular dichroism (CD) spectra with the literature. All compounds were evaluated for their antibacterial activities and cytotoxic activities.

Four new xanthene derivatives, penicixanthenes A–D (1–4), and one known compound 5 were isolated from a marine mangrove endophytic fungus Penicillium sp. JY246 that was obtained from the stem of Ceriops tagal. Their structures were determined by detailed NMR, MS spectroscopic data, modified Mosher’s method, and calculated electronic circular dichroism data. All of the isolated compounds were examined for insecticidal activity. Compounds 2 and 3 showed growth inhibition activity against newly hatched larvae of Helicoverpa armigera Hubner with the IC₅₀ values 100 and 200 μg/mL, respectively, and compounds 1, 3, and 4 showed insecticidal activity against newly hatched larvae of Culex quinquefasciatus with LC₅₀ values of 38.5 (±1.16), 11.6 (±0.58), and 20.5 (±1) μg/mL, respectively. The four xanthene derivatives have the potential to be developed as new biopesticides.

Three new lactones penicilactones A−C (1−3) were obtained from the mangrove-derived fungus Penicillium sp. TGM112. Their structures and absolute configurations were determined by detailed NMR, MS spectroscopic data, Mo₂(OAc)₄-induced electronic circular dichroism (ECD), and circular dichroism (CD) spectroscopy. Compound 1 showed antibacterial activity against Staphylococcus aureus with an MIC value of 6.25 μg/mL. Compound 2 showed insecticidal activity against newly hatched larvae of Culex quinquefasciatus with the LC₅₀ value of 78.5 (±0.58) μg/mL.

Five new compounds, including two cyclopiane diterpenes conidiogenones J and K (1–2), a steroid andrastin H (5), an alkaloid (Z)-4-(5-acetoxy-N-hydroxy-3-methylpent-2-enamido) butanoate (6), and an aliphatic acid (Z)-5-acetoxy-3-methylpent-2-enoic acid (7), together with ten known compounds (3–4 and 8–15) were isolated from the EtOAc extract of the fermentation broth of the Lumnitzera littorea-derived fungus Penicillium oxalicum HLLG-13. Their structures were elucidated by 1D, 2D NMR, and HR-ESI-MS spectral analyses. The absolute configurations of 1, 2, 5, and 8 were determined by quantum chemical electronic circular dichroism (ECD) calculations, and the absolute configuration of 8 was determined for the first time. Compound 15 was a new natural product, and its NMR data were reported for the first time. Compounds 5 and 9–14 exhibited antibacterial activities against Staphylococcus epidermidis and Candida albicans, with MIC values ranging from 6.25 to 25 μg/ mL. Compounds 1–6 and 9–14 showed significant growth inhibition activities against newly hatched Helicoverpa armigera Hubner larvae, with IC₅₀ values ranging from 50 to 200 μg/mL.