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- Evaluation of proximate composition, antioxidant properties, and phylogenetic analysis of two edible seaweedsPublication . Rathinam, Raja; Hemaiswarya, Shanmugam; Sridhar, Sekaran; Alagarsamy, Arun; Ganesan, Venkatesan; Elumalai, Sanniyasi; Carvalho, Isabel S.The present study was evaluated for the proximate composition (moisture, carbohydrate, protein, and lipid contents) of two seaweedsGracilaria corticata(Rhodophyceaen) andHalimeda opuntia(Chlorophycean). Phylogenetic analysis based on the SSU (small subunit) rRNA ascertained their molecular identification. The results showed that the carbohydrate (5.72 +/- 0.05 g/100 g), protein (42.38 +/- 0.08 g/100 g), and total lipids (10.09 +/- 0.06 g/100 g) are elevated inG. corticatawhen compared toH. opuntia. H. opuntiahad a protein content of 3.51 +/- 0.072 g/100 g and higher moisture content (95 +/- 0.45 g/100 g). The methanolic extracts ofG. corticataandH. opuntiawere used to examine the antioxidants (viz. TPC, TFC, DPPH, and FRAP) and antidiabetic (alpha-glucosidase) properties. The antioxidant results of the methanolic extract ofG.corticataexhibited a higher amount of phenolic compounds (13.37 +/- 0.01 mg GAE/g dry wt.) compared toH. opuntia. But in the case of flavonoids,H.opuntiacontained a slightly higher amount of quercetin equivalent 9.56 +/- 0.26 mg/g dry wt. In FRAP,H.opuntiashowed an elevated level (62.02 mg TE/g dry wt). DPPH scavenging activity in the seaweed extracts were recorded in the following order:H.opuntiaandG.corticata. The amino acid content ofH.opuntiawas 0.097 +/- 0.56 (mg/g) and 0.086 +/- 0.42 (mg/g) was recorded inG.corticata. [GRAPHICS.]
- Brown seaweeds as a source of anti-hyaluronidase compoundsPublication . Arunkumar, K.; Raj, Reeshma; Rathinam, Raja; Carvalho, Isabel SHyaluronidase enzymes disrupt hyaluronic acid, causing angiogenesis, tumor invasiveness, metastasis, inflammation, and skin aging. Phlorotannin, alginate and fucoidan were extracted successively from the blade and stipe samples of two Sargassum seaweeds and Eisenia arborea thallus. These were evaluated for their in vitro anti-hyaluronidase and antioxidant activities (DPPH and reducing power assay). The crude phlorotannin content was highest in the blade of S. tenerrimum (22.405 +/- 3.6 mu g/mg), followed by S. vulgare blade (18.385 +/- 3.29 mu g/mg) with lower amounts in the stipe portion. The highest yield of alginate and fucoidans was obtained from the blade samples of S. vulgare (0.322 +/- 0.38 and 0.198 +/- 0.016%), followed by S. tenerrimum (0.090 +/- 0.01 and 0.063 +/- 0.005%) and E. arborea thallus (0.047 +/- 0.008 and 0.032 +/- 0.003%). The sulfate content was higher in fucoidan than alginate extracted from the stipe regions of the seaweeds. Phlorotannin, fucoidan and alginate from S. vulgare, S. tenerrimum, and E. arborea possessed anti-hyaluronidase activity as evident by a decrease in the N-acetylglucosamine release. The highest anti-hyaluronidase activity was achieved in the extract of S. tennerimum blade (37.67 +/- 2.3% inhibition) due to its high phlorotannin content. Alginate and fucoidan extracted from the stipes of Sargassum species possess higher bioactivities than the blade samples. The FTIR study ascertained that alginate with a high guluronic acid and high sulfated fucoidan were extracted from the stipe samples compared to the blade samples. This increased viscosity and promoted bioactivity respectively. Further studies to evaluate the emulsifying and viscosity properties of these compounds are required before they can be considered for commercial applications.
- Antioxidant and cytotoxic activities of sulfated polysaccharides from five different edible seaweedsPublication . Arunkumar, K.; Rathinam, Raja; Kumar, V. B. Sameer; Joseph, Ashna; Shilpa, T.; Carvalho, Isabel S.In recent times, there has been a growing interest in the exploration of antioxidants and global trend toward the usage of seaweeds in the food industries. The low molecular weight up to 14 kDa sulfated polysaccharides of seaweeds (Portieria hornemannii, Spyridia hypnoides, Asparagopsis taxiformis, Centroceras clavulatum and Padina pavonica) were evaluated for in vitro antioxidant activities and cytotoxic assay using HeLa cell line and also characterized by FTIR. The high yield (7.74% alga dry wt.) of sulfated polysaccharide was observed in P. hornemannii followed by S. hypnoides (0.69%), C. clavulaum (0.55%) and A. taxiformis (0.17%). In the brown seaweed P. pavonica, the sulfated polysaccharide yield was 2.07%. High amount of sulfate was recorded in the polysaccharide of A. taxiformis followed by C. clavulaum, P. pavonica, S. hypnoides and P. hornemannii as indicative for bioactivity. The FTIR spectroscopic analysis supports the sulfated polysaccharides of S. hypnoides, C. clavulatum and A. taxiformis are similar to agar polymer whereas the spectral characteristics of P. hornemannii have similarities to carrageenan. The higher DPPH activity and reducing power were recorded in the polysaccharide of brown seaweed P. pavonica than the red seaweeds as follows: DPPH activities: S. hypnoides > A. taxiformis > C. clavulatum > P. hornimanii; Reducing power: A. taxiformis > P. hornimanii > S. hypnoides > C. clavulatum. The polysaccharide fractions contain up to 14 kDa from red seaweeds P. hornemannii and S. hypnoides followed by brown seaweed P. pavonica exhibit cytotoxic activity in HeLa cancer cell line (and are similar to structural properties of carrageenan extracted from P. hornemannii). The low molecular weight agar like polymer of S. hypnoides and alginate like brown seaweed P. pavonica showing better in vitro antioxidant activities that are capable of exhibiting cytotoxicity against HeLa cell line can be taken up further in-depth investigation for nutraceutical study.
- Phycoremediation potential of Chlorella sp. on the polluted Thirumanimutharu river waterPublication . Narayanan, Mathiyazhagan; Prabhakaran, Murugan; Natarajan, Devarajan; Kandasamy, Sabariswaran; Rathinam, Raja; Saraiva De Carvalho, Isabel; Ashokkumar, Veeramuthu; Chinnathambi, Arunachalam; Alharbi, Sulaiman Ali; Devarayan, Kesavan; Pugazhendhi, ArivalaganRivers are the most significant natural resources that afford outstanding habitation and nourishment for numerous living organisms. Urbanization and industrialization pollute rivers rendering their water unhealthy for consumption. Hence, this work was designed to find a potential native pollutant removing algae from polluted water. The physicochemical properties of the tested river water such as Electric Conductivity (EC), turbidity, total hardness, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Ca, SO2-, and NH3, NO3, NO2, PO4, Mg, F- and Cl- contents were not within the permissible limits. Lab-scale and field-based phycoremediation treatments with the indigenous native microalgal species, Chlorella sp. from the Thirumanimutharu river water sample were set up for 15 days with three different (Group I, II, and III) biomass densities (4 × 104, 8 × 104, and 12 × 104 cells mL-1). Group III of both the lab-scale and field based treatments showed the maximum reduction in the physicochemical parameters compared to the other groups. Further, the group III of the field based study showed an extensive reduction in BOD (34.51%), COD (32.53%), NO3, NO2, free NH3 (100%) and increased dissolved oxygen (DO) (88.47%) compared to the lab scale study. In addition, the trace elements were also reduced significantly. The pollutant absorbing active functional moieties (O-H, CO, and CN) found on Chlorella sp. had been confirmed by Fourier-Transform Infrared Spectroscopy (FTIR) analysis. In the Scanning Electron Microscope (SEM) study, significant morphological changes on the surface of the treated Chlorella sp. were noticed compared with the untreated Chlorella sp. biomass, which also confirmed the absorption of the pollutants during treatment.
- Assessment of microbial diversity and enumeration of metal tolerant autochthonous bacteria from tailings of magnesite and bauxite minesPublication . Narayanan, Mathiyazhagan; Devarajan, Natarajan; He, Zhixia; Kandasamy, Sabariswaran; Ashokkumar, Veeramuthu; Rathinam, Raja; Carvalho, Isabel S.The magnesite and bauxite mines are a major source for some minerals and metals. The tailings of these magnesite and bauxite mines contains massive amount of Mn. (3221.2 +/- 6.51 & 7102.8.4 +/- 10.24), Cd (40.95 +/- 2.12 & 892.86 +/- 8.48), Zn (951.08 +/- 4.31 &724.12 +/- 3.18), and Pb (425.8 +/- 5.21 & 812.13 +/- 9.19 mg Kg(-1)) with alkaline and acid pH respectively. In the microbial diversity analysis, the results 8 (Thiobacillus thiooxidans, Leptospirillum ferrooxidans, Acetobacter methanolicus, T. intermedius, Bacillus cereus, Sulfobacillus acidophilus, Methylobacterium sp, and Thiobacillus ferooxidans) and 12 (Serratia marcescens, Metalogenium symbioticum 1, Metallogenium symbioticum 2, Bacillus alcalophilus, Aminobacter sp, Naumaniella neustonica, Staphylococcus aureus 1, Methylbacillus sp, Pandoraea sputorum, Acenetobacter sp, S. aureus 2, Pseudomonas aeruginosa) bacteria species were isolated from bauxite and magnesite mine tailings. The fungus such as Rhizopus arrhizus, Mucor sp, Aspergillus niger and Penicillium sp were obtained in both acid and alkaline environment. Among this microbial diversity, P. sputorum and B. cereus (identified through 16S rDNA sequencing) were shown better resistance to these four metals for up to 250 mg L-1. The bacterial diversity indexes, concludes that there was least diverse among the three sites. The evenness/equitability index also conform lower level of variation among these sites. (C) 2019 Elsevier Ltd. All rights reserved.