Table 3.

Anti-microalgal activity of different extracts from seaweeds.

Macroalgae	Fraction Used or Solvent	Target Species	Effects	Reference
Enteromorpha intestinalis	Ethanol extract Fresh tissue	Prorocentrum micans	Fresh tissue and ethanol extracts significantly inhibited the growth of P. micans.	[149]
Sargassum thunbergii	Methanol extract	Heterosigma akashiwo Skeletonema costatum Prorocentrum micans	Stronger inhibitory effects on the growths of red tide microalgae tests.	[20]
Enteromorpha clathrata, Undaria pinnatifida Laminaria japonica Porphyra tenera Ulva pertusa	Seawater extracts	Skeletonema costatum	The macroalgal extracts of P. tenera, E. clathrata, and U. pertusa showed strong growth inhibition on S. costatum.	[19]
Gracilaria lemaneiformis Ulva pertusa	Fresh thalli Water-soluble extract Dry powder	Heterosigma akashiwo	Algicidal effects of both macroalgae on H. akashiwo, cells were entirely killed.	[150]
Gracilaria tenuistipitata	Dry powder	Prorocentrum micans	Inhibitory effect on the photosynthesis of P. micans.	[151]
Ulva lactuca	Dry powder Fresh thalli Extracts	Aureococcus anophagefferens Cochlodinium polykrikoides Pseudo-Nitzschiamultiseries Prorocentrum minimum Karlodinium veneficum Chattonella marina Karenia brevis	The fresh thalli and dry powder strongly inhibited the growth of all seven HAB species with advantage of dry powder. The extracts of U. lactuca exhibited dramatic allelopathic effect on the HAB species.	[152]
Sargassum thunbergii Corallina pilulifera Ulva pertusa	Aqueous extracts Fresh tissue Dry powder	Heterosigma akashiwo Alexandrium tamarense	The growth of the two microalgae was strongly inhibited	[153]
Asparagopsis taxiformis	Methanol extract	Trichodesmium sp.	Total inhibition of Trichodesmium sp. growth	[154]
Hypnea musciformis	Methanol extract	Isochrysis galbana Chlorella salina	Enhancement growing of both microalgae even at low concentration	[155]
Gracilaria lemaneiformis	Ethanol extract	Prorocentrum donghaiense Skeletonem acostatum Heterosigma akashiwo Amphidinium carterae Phaeocystis globa Karenia mikimitoi	Inhibitory effect on the growth of all microalgae	[84]
Ulva pertusa	Methanol extract	Red tide microalgae Feed microalgae	The methanolic extract showed antialgal activity against red tide, with no growth inhibition for feed microalgae.	[156]
Corallina pilulifera	Methanol extract	Red tide microalgae Feed microalgae	Stronger inhibitory effects on the growths of red tide microalgae, with no growth inhibition for feed microalgae.	[157]
Ulva intestinalis	Ethanol extract Fresh tissue Dry powder	Heterosigma akashiwo Prorocentrum micans	The fresh tissue, dry powder and extract, all exhibited obvious algicidal effects on red tide microalgae.	[83]
37 species	Methanol extract Water extract	Heterosigma akashiwo	The green alga Ulva fasciata showed the strongest algicidal activity among the 37 seaweeds tested	[142]
Ulva lactuca Ulvafasciata	Ethanol extract	Chlorella vulgaris	Stimulation of growth and progressive increase of Chlorella vulgaris biomass	[158]
Ulva pertusa Ulva prolifera	Extracts (acetone, ether chloroform, methanol) Fresh tissue Dry powder	Prorocentrum donghaiense	Stronger inhibitory growing effects by fresh tissue and dry powder of both seaweeds. Methanol extracts of the macroalgae were found to strongly inhibit the growth of P. donghaiense.	[159]
Ecklonia kurome	Phlorotannins extract	Cochlodinium polykrikoides Chattonella antiqua Kareniam ikimotoi	Destruction of 99% cells of ride tide microalgae, with no mortality observed among other organisms such us: Pagrus major, tiger puffer Fugu rubripes or larval blue crab Portunustrituberculatus.	[120]
Ulva pertusa	Fresh tissue	Heterosigma akashiwo, Skeletonema costatum, Tetraselmis subcordiformis, Nitzschia closterium, Chaetoceros gracile, Chroomonas placoidea, Isochrysis galbana, Alexandrium tamarense	Algicidal interaction between green alga Ulva pertusa and all phytoplankton species	[146]