Sadayan Paramasivam

Nanoplastics (plastic particles smaller than 1 μm) are the least-known type of marine litter. Nanoplastics (NPs) have attracted much interest in recent years because of their prevalence in the environment and the potential harm they can cause to living organisms. This article focuses on understanding NPs and their fate in the marine environment. Sources of NPs have been identified, including accidental release from products or through nano-fragmentation of larger plastic debris. As NPs have a high surface area, they may retain harmful compounds. The presence of harmful additives in NPs poses unique practical challenges for studies on their toxicity. In this review, several methods specifically adapted for the physical and chemical characterization of NPs have been discussed. Furthermore, the review provides an overview of the translocation and absorption of NPs into organisms, along with an evaluation of the release of potential toxins from NPs. Further, we have provided an overview about the existing methods suggested for the possible degradation of these NPs. We conclude that the hazards of NPs are plausible but unknown, necessitating a thorough examination of NPs’ sources, fate, and effects to better mitigate and spread awareness about this emerging contaminant.

The present work was performed to evaluate the levels of phytochemical constituents and the antioxidant and antibacterial properties of marine red seaweed (Kappaphycus alvarezii) and seagrass (Cymodocea serrulata). Quantitative phytochemical analysis, antioxidant activity and antimicrobial activity against five potential pathogenic bacteria was investigated. In each case, we found the presence of flavonoids, tannins, phenolic compounds, glycosides, steroids, carbohydrates and ashes. Alkaloids were only found in K. alvarezii, though they were not found in C. serrulata. The antimicrobial properties of both K. alvarezii and C. serrulata chloroform extracts were found to be antagonistically effective against the Gram-positive bacteria Bacillus subtilis and the Gram-negative bacteria Vibrio parahaemolyticus, Vibrio alginolyticus, Vibrio harveyi and Klebsiella pneumoniae. GC-MS analysis revealed the presence of 94 bioactive compounds in K. alvarezii and 104 bioactive compounds in C. serrulata, including phenol, decane, dodecane, hexadecane, vanillin, heptadecane, diphenylamine, benzophenone, octadecanoic acid, dotriaconate, benzene, phytol, butanoic acid and 2-hydroxyl-ethyl ether, which all played important roles in antioxidant and antibacterial activities. Thus, in view of the results, both K. alvarezii and C. serrulata could be considered to be sources of ingredients with appreciable nutritional and medicinal value.

The present work was performed to evaluate the levels of phytochemical constituents and the antioxidant and antibacterial properties of marine red seaweed (Kappaphycus alvarezii) and seagrass (Cymodocea serrulata). Quantitative phytochemical analysis, antioxidant activity and antimicrobial activity against 5 potential pathogenic bacteria was investigated. In both cases were found presence of flavonoids, tannins, phenolic compounds, glycosides, steroids, carbohydrates and ashes. Alkaloids were only found in K. alvarezii, buy not in C. serrulata. The antimicrobial properties of both K. alvarezii and C. serrulata chloroform extracts were found to be antagonis-tically effective against the gram-positive bacterium Bacillus subtilis and the gram-negative bacterium Vibrio parahaemolyticus, Vibrio alginolyticus, Vibrio harveyi and Klebsiella pneu-moniae. GC‒MS analysis revealed the presence of 94 bioactive compounds in K. alvarezii and 104 C. serrulata, including phenol, decane, dodecane, hexadecane, vanillin, heptadecane, diphenyla-mine, benzophenone, octadecanoic acid, dotriaconate, benzene, phytol, butanoic acid, and 2-hydroxyl-ethyl ether, which played a vital role in antioxidant and antibacterial activities. Thus, in view of the results, both K. alvarezii and C. serrulata could be considered as sources of ingre-dients with appreciable nutritional and medicinal value.

The aim of the present study was to assess the occurrence of seven biogenic amines (cadaverine, histamine, putrescine, tryptamine, tyramine, spermidine, and spermine) in 13 fresh fish, three crustaceans, and three cephalopod species, as well as six cured and dried fish products commonly consumed in the southeast coast region of India. The biogenic amines were analyzed by high performance liquid chromatography with a dansyl chloride derivatization. In the majority of the cases, the biogenic amine content was within the limits set at both national and international levels. The only exceptions were the histamine content of fresh Silago sihama, Lutjanus bohar, and L. johnii, cured and dried Rastrelliger kanagurta and the tyramine content of cured and dried Penaeus indicus. In these cases, lack of proper temperature handling was indicated, which highlights the importance of establishing and implementing proper handling procedures to ensure fish and fishery product safety for human consumption. Graphical Abstract

Hypnea musciformis (HM) and Acanthophora muscoides (AM) red seaweeds were evaluated for their antioxidant properties and efficacy to extend the chemical shelf life of black tiger shrimp (Penaeus monodon) during 14-daystorage. Treated shrimp were soaked in five percent ethanolic solution with 500 µg/mL of AM or HM powder for 30 min. HM had more phenols and flavonoids, increased radical scavenging activity, and greater H₂O₂ reducing power than AM in vitro. Biochemical quality indicators were significantly higher in the control group, followed by HM- and AM-treated samples during storage. On day 14 of storage, controls contained significantly higher amounts of biogenic amines than HM- or AM-treated samples. The shelf life of chilled stored shrimp increased due to the presence of compounds of butylated hydroxytoluene, sulfurous acid, heptadecane, mono (2-ethylhexyl), and 1,2-propanediol found in AM extract and sulfurous acid and 1,2-propanediol found in HM extract. A control group was soaked in the same ethanolic solution as treated samples without algae powder for 30 min. Each group was kept ice-cold during the soaking period. The results obtained demonstrate the usefulness of two seaweed extracts, Hypnea musciformis and Acanthophora muscoides, combined with ice by decreasing the formation of toxic biogenic amines in shrimp, enhancing its shelf life during ice storage.