Related Experiment Video
Updated: Sep 21, 2025
Isolation and Selection of Entomopathogenic Fungi from Soil Samples and Evaluation of Fungal Virulence against Insect Pests
Published on: September 28, 2021
Cyclodepsipeptides: Isolation from Endophytic Fungi of Sarcophyton ehrenbergi and Verification of Their Larvicidal
Abdel Nasser B Singab1,2, Nada M Mostafa1, Yasmin A Elkhawas3
1Department of Pharmacognosy, Faculty of Pharmacy, Ain-Shams University, Cairo 11566, Egypt.
Abstract:
Culex pipiens mosquitoes are vectors to many viruses and can transmit diseases such as filariasis and avian malaria. The present study evaluated the larvicidal activity of marine-derived endophytic fungi Aspergillus nomius and Aspergillus flavus from the soft coral Sarcophyton ehrenbergi along with two known cyclodepsipeptide compounds, scopularide A (1) and B (2), isolated from A. flavus extract, against third-instar larvae of C. pipiens, using distilled water as a negative control and toosenedanin as a positive control. The structures of the isolated compounds were confirmed by various spectroscopic analyses. The lethal concentrations (LC50 and LC90) were calculated by probit analysis. Scopularide A was the most potent after 96 h treatment, with LC50 and LC90 values of 58.96 and 994.31 ppm, respectively, and with 82.66% mortality at a concentration of 300 ppm. To unravel the biochemical mechanism of the tested extracts and compounds, their effects against protease, chitinase, phenoloxidases and lipase enzymes from the whole-body tissue of C. pipiens were evaluated after 72 h treatment at LC50 dose. Superior activity was observed for A. flavus extract against all tested enzymes. A molecular docking study was conducted for scopularide A and B on the four tested enzymes, to further verify the observed activity. Results revealed good binding affinities for both compounds as compared to the docked ligands, mainly via a number of hydrogen bonds. This was the first study to report the isolation of endophytic fungi A. flavus and A. nomius from the marine soft coral S. ehrenbergi. The endophytic fungal extract of A. flavus was found to be a promising source for a natural larvicidal agent against C. pipiens populations.
Insights
Marine fungi Aspergillus flavus and Aspergillus nomius show larvicidal activity against Culex pipiens mosquitoes. Aspergillus flavus extract and scopularide A demonstrated potent mosquito-killing properties, offering a natural approach to disease vector control.
Area of Science:
- Marine natural products chemistry
- Medical entomology
- Microbiology
Background:
- Culex pipiens mosquitoes transmit diseases like filariasis and avian malaria.
- Marine-derived endophytic fungi are a potential source of bioactive compounds.
- Novel larvicidal agents are needed to control mosquito populations.
Purpose of the Study:
- To evaluate the larvicidal activity of endophytic fungi Aspergillus nomius and Aspergillus flavus from Sarcophyton ehrenbergi.
- To assess the efficacy of isolated compounds scopularide A and B against Culex pipiens larvae.
- To investigate the biochemical mechanisms underlying the larvicidal effects.
Main Methods:
- Isolation and identification of endophytic fungi from marine soft coral Sarcophyton ehrenbergi.
- Larvicidal bioassays against third-instar Culex pipiens larvae using fungal extracts and isolated compounds.
- Determination of lethal concentrations (LC50 and LC90) and enzyme inhibition assays (protease, chitinase, phenoloxidases, lipase).
- Molecular docking studies to predict binding interactions with target enzymes.
Main Results:
- Aspergillus flavus and Aspergillus nomius were successfully isolated from Sarcophyton ehrenbergi.
- Scopularide A exhibited potent larvicidal activity with LC50 of 58.96 ppm and LC90 of 994.31 ppm after 96 hours.
- Aspergillus flavus extract showed superior inhibition against all tested enzymes, suggesting a broad biochemical mechanism.
- Molecular docking revealed favorable binding affinities for scopularide A and B with target enzymes.
Conclusions:
- This study is the first to report the isolation of endophytic fungi Aspergillus flavus and Aspergillus nomius from the marine soft coral Sarcophyton ehrenbergi.
- The endophytic fungal extract of Aspergillus flavus is a promising natural larvicidal agent against Culex pipiens.
- Scopularide A and B possess significant larvicidal potential, warranting further investigation for mosquito control strategies.
