Bioactivity and constituents of several common seaweeds

Abstract

Bioactivity and constituents of 8 common seaweeds from Dalian intertidal zone of northern Yellow Sea were investigated. In the anti-methicillin-resistant Staphylococcus aureus (MRSA) test, Symphyocladia latiuscula and Enteromorpha intestinalis showed obvious activities with MICs much lower than 1.0 mg mL 1 . In the DNA damage repair test (DDRT), Chondrus ocellatu showed selective inhibitory activity against the DNA repair-defective E. coli strain vs. the wild-type E. coli strain; while Sym. latiuscula, Enteromorpha intestinalis and Sar. kjellmanianum showed significant anti-E. coli activity with MICs of 64-128 g mL 1 . In the anti-Pyricularia oryzae test, Sym. latiuscula and Rh. confervoides strongly inhibited the germination of the spores of P. oryzae on agar plate. In the brine shrimp larvicidal test, Sym. latiuscula, Rh. confervoides and Sar. kjellmanianum exhibited potent toxicity against brine shrimp larvae, with LC 50 much lower than 1 mg mL 1 . The HPTLC analysis revealed their diversified secondary metabolites. The HPLC-DAD-MS analysis of the strongest species Sym. latiuscula and database searching showed that it can produce quite diversified metabolites, including halogenated ones, some of which may be new natural products. The results demonstrated the potentials of these seaweeds in the development of new antibiotics, antitumor drugs, agricultural fungicides and pesticides. Macroalgae are important primary producers of marine and coastal ecosystem and are also useful medicine and pesticide resources due to their potentials in accumulating large quantities of bioactive metabolites [1]. As is known to all, algal diversity and biomass depend on the environmental factors such as temperature, light, and nutrition, which can be influenced by human activities (e.g. introducing species and pollutions in the form of heat and eutrophication). Therefore, it is important to investigate and utilize the algal resources in coastal zones. Dalian, an important harbor and industrial city, is located on the tip of the Liaodong Peninsula, between China's inner Bohai Sea and the north Yellow Sea. Its marine ecological environment is influenced by strong sea currents and rivers, which provides diversified habitats for seaweeds and also brings about human influences. In this article, we evaluated the biomass and their biomedical and agrichemical potentials as new antibiotics, antitumor drugs, agricultural fungicides, and pesticides in some common seaweeds from Dalian coastline by determining several bioactivities of them, including anti-methicillin-resistant Staphylococcus aureus (MRSA), anti-Escherichia coli DNA repair-defective/wildtype strains, anti-Pyricularia oryzae, and anti-brine shrimp (Artemia parthenogenetica L.) larvae.

Mosquitocidal and Oviposition Repellent Activities of the Extracts of Seaweed Bryopsis pennata on Aedes aegypti and Aedes albopictus

“…Then, accurate mass data and molecular formula were used to corroborate with the data in Dictionary of Natural Products [59] and Dictionary of Marine Natural Products [60]. During the comparison of data, factors like biological resource, compound category and polarity’s reasonability were taken into account to rule out the unreasonable hits [61].…”

Preliminary screening of the aqueous extracts of twenty-three different seaweed species in Sri Lanka with in-vitro and in-vivo assays

“…The brine shrimp lethality assay is very important as a preliminary toxicity screening of any biological compound or product since it is a comparatively easy and cheap method which provides the basic information useful to extend further cytotoxicity tests; in-vitro or in-vivo though a few of the studies have been carried out to check the cytotoxicity of seaweeds using brine shrimp test (Zhang et al, 2013). Toxicity index values (LC 50 ) of extracts are used to find out whether the extracts are toxic or non-toxic.…”

Marine Macroalgae, a Source of Natural Inhibitors of Fungal Phytopathogens

“…[63], Phialophora cinerescens, Phoma tracheiphila [65], Sclerotinia sclerotiorum, Sclerotium rolfsii [92], and Verticillium dahliae [63,93] are some examples of fungi that only presented susceptibility to algae extracts belonging to the class Phaeophyceae. Exceptions were found in the species Colletotrichum gloeosporioides, Pseudocercospora fijiensis [94], and Pyricularia oryzae [95], which were only inhibited by red algae, a group also possessing a large amount of diverse relevant compounds [96]. The genus Alternaria is one of the most prevalent phytopathogenic groups, responsible for soft-rotting infections and Alternaria blight in apple trees and tomato plants, respectively, leading to important fruit losses [58,97].…”

“…Dictyota implexa Disc diffusion technique [65] Dictyota spiralis Disc diffusion technique [65] Pseudocercospora fijiensis Halymenia floresii Minimum inhibitory concentration [94] Pyricularia oryzae Rhodomela confervoides Spore spreading method [95] Symphyocladia latiuscula Spore spreading method [95] Rhizoctonia solani…”