Insecticidal activity of forty-seven marine algae species from the Mediterranean, Aegean, and Sea of Marmara in connection with their cholinesterase and tyrosinase inhibitory activity

Ethanolic extracts prepared from forty-seven macroalgae species collected from the Mediterranean Sea, Aegean Sea, and Sea of Marmara were tested at 200 mu g/mL against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and tyrosinase (TYR), crucial for insect vivacity. Only one alga extract, e.g. Dictyota dichotoma var. intricata (C.Agardh) Greville 1830, had a notable inhibition of BChE (72.0 +/- 0.07%), whereas the rest of the macroalgae possessed no or low inhibition of AChE (2.20 +/- 0.39% - 14.20 +/- 2.16%), BChE (0.62 +/- 0.07% - 41.20 +/- 3.07%), and TYR (< 10%). Several known diterpenes (isoamijiol, 14-deoxyamijiol, amijidictyol, dictyodial, and 4 alpha-acetoxydictyodial) found earlier in this species were proceeded to molecular docking experiments to figure out its interactions with BChE. Eleven of the 47 macroalgal extracts were selected based on sufficient availability for testing in larvicidal and adulticidal activity assays against female Aedes aegypti Orlando1952 the mosquito vector of yellow fever and dengue. The selected extracts displayed a high adulticidal activity ranging between 80-100% activity at 5 mu g/mosquito. In contrast, only the ethanol extract of Ceramium siliquosumvar. elegans showed larvicidal mortality of 93.3 +/- 11.5% at 0.5 mu g/mL. Our findings show that the macroalgae and their metabolites could be sources of novel insecticidal agents. (C) 2021 SAAB. Published by Elsevier B.V. All rights reserved.

Automated summary

Ethanolic extracts from 47 macroalgae species were tested for their effects on insect vitality-related enzymes, with only one extract showing notable inhibition of butyrylcholinesterase. Furthermore, 11 extracts displayed high larvicidal and adulticidal activities against the mosquito vector Aedes aegypti, indicating the potential of macroalgae and their metabolites as novel insecticidal agents.