Cyclodepsipeptides: Isolation from Endophytic Fungi of Sarcophyton ehrenbergi and Verification of Their Larvicidal Activity via In-Vitro and In-Silico Studies

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.

In Silico Docking, Resistance Modulation and Biofilm Gene Expression in Multidrug-Resistant Acinetobacter baumannii via Cinnamic and Gallic Acids

“…The docking study was conducted to demonstrate the binding affinities of the tested compounds to the active sites of the protein [ 80 , 81 ]. The study was performed using Molecular Operating Environment (MOE 2019.02) software [ 82 , 83 ].…”

Phytochemical Investigation of Three Cystoseira Species and Their Larvicidal Activity Supported with In Silico Studies

“…Also, developing larvicides from marine sources might be another technique of mosquito control. Success stories in the search for pesticides with a natural origin have been documented [ 9 , 10 , 11 , 12 ].…”

Marine natural products

“…The cyclodepsipeptides, scopularides A and B displayed potent larvicidal activity against mosquito ( Culex pipiens ) larvae, 277 alkaloids epi -aszonalenin A and aszonalenin were shown to inhibit angiogenesis by inhibition of inflammation and apoptosis 278 and cyclodepsipeptide isaridin E was shown to downregulate the PI3K/Akt signalling pathway and thus possesses antiplatelet and antithrombotic effects. 279 The alkaloid meleagrin had a protective effect in mice against pulmonary fibrosis induced by bleomycin 280 and epidithiodiketopiperazine N -methylpretrichodermamide B displayed potent inhibition of P-glycoprotein and was able to resensitise drug resistant cells to docetaxel.…”