Marine red algae, particularly Gracilaria Greville species, are rich in bioactive compounds with significant therapeutic potential. Hence, Gracilaria sp. can effectively combat bacterial infections and oxidative stress through its diverse bioactive compounds. Despite their potential, the bioactive profile and antibacterial efficacy of Gracilaria sp. remain largely unexplored. Therefore, Gracilaria sp. was isolated from the east coast of Chilika Lake of Odisha, and its methanolic and phenolic crude extracts were assessed for antibacterial activity against clinically relevant multidrug-resistant (MDR) bacterial pathogens. This study specifically aimed to investigate the antibacterial potential of these extracts against two pathogenic bacteria: Staphylococcus aureus and Klebsiella pneumoniae. The methanolic extract exhibited the strongest inhibitory activity against K. pneumoniae, producing an inhibition zone of 43 mm. The phenolic extract created the greatest inhibition zone > 45 mm against S. aureus. Phytochemical screening and chemical profiling using FT-IR and GC-MS identified a range of bioactive compounds including hexadecenoic acid methyl ester, benzofuran derivatives, phytol, heptadecane, tridecane, various esters and hydrocarbons. These compounds potentially contribute to the observed antimicrobial effects. These findings highlight that Gracilaria sp. holds promise as a significant source of natural antibacterial agents, particularly in the fight against MDR bacteria.
Chlorella is a genus of unicellular, photosynthetic green microalgae characterized by their intense green color, derived from a high chlorophyll content. These microalgae have exceptional nutritional value and therapeutic potential, making them an important focus of study with diverse applications in the food and pharmaceutical sectors. This review addresses the nutritional composition and diverse biological activities, such as antibacterial, antiviral, immunomodulatory, antidiabetic, hypolipidemic, antioxidant, and anticancer properties of Chlorella microalgae. Furthermore, based on recent studies, the bioactive compounds and possible mechanisms responsible for these biological activities are elaborated. Chlorella provides health benefits for those who consume it, and its cultivation could positively impact sectors such as the economic, environmental, and social sectors.
Marine algae are rich biological resources containing a wide range of bioactive compounds with significant therapeutic and industrial potential. This review considers the chemical characterization and biological activities of several marine algae, including Chlorophyta, Phaeophyta, and Rhodophyta. These algae are known to contain active compounds such as flavonoids, phenolics, terpenoids, sulfated polysaccharides, and fucoxanthin, which exhibit antioxidant, antibacterial, anticancer, and anti-inflammatory activities. Isolation and characterization techniques include solvent extraction, chromatography (GC-MS, LC-MS, HPLC), and spectroscopy (UV-Vis, NMR, FTIR). Marine algae also show promising applications in the cosmetic, functional food, bioenergy, and bioremediation industries. This study highlights the importance of sustainably utilizing marine algae as therapeutic agents and bio-based industrial raw materials.
An 8-10 m marine terrace of the western Alaskan coast was investigated here. Three diatom associations were identified in these sediments, reflecting climatic and sea-level changes during the first interglacial period of the late Pleistocene (MIS 5). A complex of marine diatoms was found in sandy sediments at the section base. Higher in the section they are replaced by swamp diatoms found in peat unit. A marine coastal complex was discovered in the loams at the top of the section. These three assemblages are correlated with substages 5e, 5d, and 5c of Marine Isotope Stage 5 and stages of the Pelukian transgression of Alaska. The relatively high position of the layers bearing marine diatoms in relation to the modern coastline indicates the emergence of glacioisostatic movements after the glaciation of late Wisconsin.
Seaweed extracts have attracted attention as natural bio stimulants due to their rich composition of bioactive compounds that enhance plant growth and development. The present study aimed to assess the effect of seaweed liquid extract made from three algae, a Caulerpa chemnitzia (Esper) J.V.Lamouroux (Chlorophyceae), Sargassum wightii Greville (Phaeophyceae) and Gracilaria corticata (J.Agardh) J.Agardh (Rhodophyceae), as a biostimulant agent in seed germination and vegetative growth of the plant Vigna unguiculata. Here, we found that the 60% extract promoted maximum root length and shoot length along with increased chlorophyll a, chlorophyll b, total chlorophyll and free amino acid content of the test plant. Furthering our knowledge of the potential biostimulant effect of seaweed liquid extracts could facilitate more sustainable food production.
