Antibacterial and antioxidant activity of naphthofuranquinones from the twigs of tropical mangrove Avicennia officinalis

New Meroterpenoid and Isocoumarins from the Fungus Talaromyces amestolkiae MST1-15 Collected from Coal Area

Three new compounds including a meroterpenoid (1) and two isocoumarins (8 and 9), together with thirteen known compounds (2-7, 10-16) were isolated from the metabolites of Talaromyces amestolkiae MST1-15. Their structures were identified by a combination of spectroscopic analysis. The absolute configuration of compound 1 was elucidated on the basis of experimental and electronic circular dichroism calculation, and compounds 8 and 9 were determined by Mo₂(OAc)₄-induced circular dichroism experiments. Compounds 7-16 showed weak antibacterial activities against Stenotrophomonas maltophilia with MIC values ranging from 128 to 512 μg/mL (MICs of ceftriaxone sodium and levofloxacin were 128 and 0.25 μg/mL, respectively).

Isolation and biological evaluation 7-hydroxy flavone from Avicennia officinalis L: insights from extensive in vitro, DFT, molecular docking and molecular dynamics simulation studies

The flavonoid based 7-hydroxy flavone (PubChem CID: 5281894; molecular formula: C₁₅H₁₀O₃) molecule has been isolated for the first time from the methanolic extract from the leaves of Avicennia officinalis L. in the tropical mangrove ecosystem of Andaman and Nicobar Islands (ANI), India. The molecular structure of bioactive compound was characterized by spectroscopic analysis, including FT-IR, ¹H, ¹³C NMR spectroscopy and ESI-HRMS and elucidated as 7-hydroxy flavone. An anticancer activity of isolated 7-hydroxy flavone was evaluated by in vitro study against two different human cancer cell lines namely, HeLa (cervical cells) and MDA-MB231 (breast cells) and they exhibited promising anticancer activity with IC₅₀ values are 22.5602 ± 0.21 µg/mL and 3.86474 ± 0.35 µg/mL, respectively. The antioxidant property of 7-hydroxy flavone at a standard concentration of 50 µg, was found to be (IC₅₀) 5.5486 ± 0.81 µg/mL. In summary, this investigation provides evidence that 7-hydroxy flavone exhibits both anticancer and antioxidant properties. Meanwhile, the antimicrobial activity ability of 7-hydroxy flavone were also evaluated using three Gram positive and two Gram negative strain exhibited no antimicrobial activities. Density-functional theory (DFT) studies confirm the structure is global minima in the PES, from the optimized geometry FMO and MESP map analyzed. Further, the molecular docking and molecular dynamics simulation studies result shows that 7-hydroxy flavone has the better binding ability with anti-apoptotic Bcl-2 protein with the estimated free energy of binding of -6.3 kcal/mol. This bioactive compound may be act as drug candidate for treating various kinds of cancers. HighlightsA 7-hydroxy flavone molecule has been isolated from Avicennia officinalis.The isolated pure compound was subjected to spectral analysis such as FT-IR, ¹H NMR, ¹³C NMR spectral data and HRMS analysis for skeleton of the molecule.The anticancer activity of 7-hydroxy flavone studied against Cervical (HeLa) cancer cell lines and breast (MDA-MB231) cancer cell lines with the IC₅₀ values of 22.5602 ± 0.21 µg/mL and 3.86474 ± 0.35 µg/mL), respectively.The antioxidant properties of 7-hydroxy flavone were found to be (IC₅₀) 5.5486 ± 0.81 µg/mL at a standard concentration of 50 µg.DFT, molecular docking and MD simulation results explained that 7-hydroxy flavone could be the most promising candidate to inhibit the function of anti-apoptotic Bcl-2 protein in cancerous cell.Communicated by Ramaswamy H. Sarma.

Targeted Isolation of Anti-Trypanosomal Naphthofuran-Quinone Compounds from the Mangrove Plant Avicennia lanata

The discovery of new secondary metabolites from natural origins has become more challenging in natural products research. Different approaches have been applied to target the isolation of new bioactive metabolites from plant extracts. In this study, bioactive natural products were isolated from the crude organic extract of the mangrove plant Avicennia lanata collected from the east coast of Peninsular Malaysia in the Setiu Wetlands, Terengganu, using HRESI-LCMS-based metabolomics-guided isolation and fractionation. Isolation work on the crude extract A. lanata used high-throughput chromatographic techniques to give two new naphthofuranquinone derivatives, hydroxyavicenol C (1) and glycosemiquinone (2), along with the known compounds avicenol C (3), avicequinone C (4), glycoquinone (5), taraxerone (6), taraxerol (7), β-sitosterol (8) and stigmasterol (9). The elucidation and identification of the targeted bioactive compounds used 1D and 2D-NMR and mass spectrometry. Except for 6–9, all isolated naphthoquinone compounds (1–5) from the mangrove plant A. lanata showed significant anti-trypanosomal activity on Trypanosoma brucei brucei with MIC values of 3.12–12.5 μM. Preliminary cytotoxicity screening against normal prostate cells (PNT2A) was also performed. All compounds exhibited low cytotoxicity, with compounds 3 and 4 showing moderate cytotoxicity of 78.3% and 68.6% of the control values at 100 μg/mL, respectively.

Transcriptome Changes in Colorectal Cancer Cells upon Treatment with Avicequinone B

Purpose: Naphtho[2,3-b]furan-4,9-dione (Avicequinone B), a natural naphthoquinone isolated from the mangrove tree Avicennia alba , is recognized as a valuable synthetic precursor with anti-proliferative effect. However, the molecular mechanism involved in its bioactivity has not been investigated. This study aimed to determine the selectivity of avicequinone B against cancer cells and the transcriptomic changes induced in colorectal cancer (CRC).

Methods: The cytotoxic effect against adenocarcinoma-derived cells or fibroblasts was evaluated using MTT assay. In addition, CRC cells were treated with avicequinone B in different settings to evaluate colony-forming ability, cell cycle progression, apoptosis/necrosis induction, and transcriptome response by RNA-seq.

Results: Avicequinone B effectively reduced the viability of breast, colorectal, and lung adenocarcinoma cells with IC₅₀ lower than 10 μM, while fibroblasts were less affected. The induction of G2/M arrest and necrosis-like cell death were observed in avicequinone B-treated HT-29 cells. Furthermore, RNA-seq revealed 490 differentially expressed genes, highlighting the reduction of interferon stimulated genes and proliferative signaling pathways (JAK-STAT, MAPK, and PI3K-AKT), as well as the induction of ferroptosis and miR-21 expression.

Conclusion: In short, these results demonstrated the therapeutic potential of avicequinone B and paved the foundation for elucidating its mechanisms in the context of CRC.