title: Therapeutic properties in Tunisian hot springs: first evidence of phenolic compounds in the cyanobacterium Leptolyngbya sp. biomass, capsular polysaccharides and releasing polysaccharides.
abstract: BACKGROUND
  In Tunisia, the use of hot spring waters for both health and recreation is a tradition dating back to Roman times. In fact, thermal baths, usually called "Hammam" are recommended as a therapeutic and prophylactic measure against many types of illness and toxicity. While the chemical concentration of thermal water is admittedly associated with its therapeutic effects, the inclusion in spa waters of efficient bioproduct additives produced by photosynthetic microorganisms and that act against oxidative stress may comprise a significant supplementary value for thermal centers. The aim of this study was to investigate the antioxidant potential of the Tunisian thermophilic cyanobacterium Leptolyngbya sp. and to determine its phytochemical constituents and phenolic profile.
  
  
  METHODS
  BME (Biomass Methanolic Extract), CME (Capsular polysaccharides Methanolic Extract) and RME (Releasing polysaccharides Methanolic Extract) of Leptolyngbya sp. were examined for their antioxidant activities by means of DPPH, hydroxyl radical scavenging and ferrous ion chelating assays. Their total phenols, flavonoids, carotenoids, Mycosporine-like amino acids (MAAs) and vitamin C contents, as well as their phenolic profiles were also determined.
  
  
  RESULTS
  BME has the highest content of phenols (139 ± 1.2 mg/g), flavonoids (34.9 ± 0.32 mg CEQ/g), carotenoids (2.03 ± 0.56 mg/g) and vitamin C (15.7 ± 1.55 mg/g), while the highest MAAs content (0.42 ± 0.03 mg/g) was observed in CME. BME presented both the highest DPPH and hydroxyl radical scavenging ability with an IC50of 0.07 and 0.38 mg/ml, respectively. The highest ferrous chelating capacity was detected in CME with an IC50= 0.59 mg/ml. Phenolic profiles revealed the presence of 25 phenolic compounds with the existence of hydroxytyrosol, oleuropein, resveratrol and pinoresinol.
  
  
  CONCLUSIONS
  The study demonstrated that the cyanobacterium Leptolyngbya sp. possesses abundant natural antioxidant products which may have prophylactic and therapeutic effects on many types of illness and toxicity. The present findings not only explain and reinforce the rationale behind traditional therapeutic practices in Tunisia in the exploitation of the country's hot springs, but support the addition of Leptolyngbya to thermal waters as a means to enhance the value and reputation of the curative nature of Tunisian thermal waters.
authors.affiliation: Laboratory of Marine Biodiversity and Biotechnology, National Institute of Marine Sciences and Technology, BP 59, Monastir, 5000, Tunisia.
authors.forename: Lamia
authors.initials: L
authors.lastname: Trabelsi
authors.affiliation: Biochemistry Laboratory, Research Laboratory in "Nutrition- Functional Food and Vascular Health" Faculty of Medicine, Monastir, 5019, Tunisia.
authors.forename: Amira
authors.initials: A
authors.lastname: Mnari
authors.affiliation: Pharmacology Department, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, 41522, Egypt.
authors.forename: Mohamed M
authors.initials: MM
authors.lastname: Abdel-Daim
authors.affiliation: Laboratory of Research on Biologically Compatible Compounds, Faculty of Dentisty, Monastir, 5019, Tunisia.
authors.forename: Salwa
authors.initials: S
authors.lastname: Abid-Essafi
authors.affiliation: Université de Bourgogne Franche-Comté, Laboratoire de Chrono-Environnement, UMR CNRS, Besançon, 6249, France. lotfi.aleya@univ-fcomte.fr.
authors.forename: Lotfi
authors.initials: L
authors.lastname: Aleya
mesh_terms: D000975:Antioxidants / Q000032:analysis; D001452:Balneology; D018533:Biomass; D002338:Carotenoids / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D000458:Cyanobacteria / Q000737:chemistry*; D005419:Flavonoids / Q000032:analysis; D045482:Hot Springs / Q000737:chemistry*; D010636:Phenols / Q000032:analysis*; D011134:Polysaccharides / Q000032:analysis
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D011134:Polysaccharides; D002338:Carotenoids
keywords: Antioxidant activities; Hot spring water; Leptolyngbya sp.; Phenolic profile; Phytochemical content