title: Chemical characterization and assessment of antioxidant potentiality of Streptocaulon sylvestre Wight, an endangered plant of sub-Himalayan plains of West Bengal and Sikkim.
abstract: BACKGROUND
  S. sylvestre Wright is an extremely rare plant, found only in the sub-Himalayan Terai region of West Bengal and neighboring Sikkim foot-hills. The plant has never been evaluated for any pharmaceutical properties. The phytochemical status of the plant is still unknown. Therefore, the aim of the study was to explore the antioxidant and free radical scavenging activities and analysis of bioactive compounds present in S. sylvestre.
  
  
  METHODS
  S. sylvestre methanolic extract (SSME) was evaluated for different free radical scavenging activities such as hydroxyl radical, nitric oxide, singlet oxygen, hypochlorous acid, peroxynitrite, superoxide radical and hydrogen peroxide scavenging etc. Iron chelating capacity and inhibition of lipid peroxidation were studied in addition to the assessment of haemolytic activity and erythrocyte membrane stabilizing activity (EMSA). Chemical characterization of SSME were performed by high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS).
  
  
  RESULTS
  The results indicate that SSME possess potent antioxidant activity with IC50 value of 113.06 ± 5.67 μg/ml, 63.93 ± 4.16 μg/ml and 142.14 ± 6.13 μg/ml for hydroxyl radical, superoxide radical and hypochlorous acid, respectively. HPLC analysis revealed presence of different phenolic secondary metabolites such as gallic acid, ferulic acid, p-coumaric acid, syringic acid, myricetin, quercetin etc. GC-MS analysis displayed the predominance of γ-sitosterol, vitamin E and squalene in SSME.
  
  
  CONCLUSIONS
  The present study provides a convincing evidence that S. sylvestre not only possess potent antioxidant activity but also can be used as a source of natural bioactive phytochemicals in the future.
authors.affiliation: Cellular Immunology Laboratory, Department of Zoology, University of North Bengal, Siliguri, 734013, West Bengal, India. priyankardey28@gmail.com.
authors.forename: Priyankar
authors.initials: P
authors.lastname: Dey
authors.affiliation: Chemical Signal and Lipidomics Laboratory, Department of Botany, University of Calcutta, Kolkata, 700019, India. ray.sandipan.bot@gmail.com.
authors.forename: Sandipan
authors.initials: S
authors.lastname: Ray
authors.affiliation: Chemical Signal and Lipidomics Laboratory, Department of Botany, University of Calcutta, Kolkata, 700019, India. mpsarkar1@rediffmail.com.
authors.forename: Mousumi Poddar
authors.initials: MP
authors.lastname: Sarkar
authors.affiliation: Cellular Immunology Laboratory, Department of Zoology, University of North Bengal, Siliguri, 734013, West Bengal, India. dr_tkc_nbu@rediffmail.com.
authors.forename: Tapas Kumar
authors.initials: TK
authors.lastname: Chaudhuri
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000032:analysis / Q000494:pharmacology*; D029062:Apocynaceae / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D003373:Coumaric Acids / Q000032:analysis / Q000494:pharmacology; D056727:Endangered Species; D005419:Flavonoids / Q000032:analysis / Q000494:pharmacology; D008401:Gas Chromatography-Mass Spectrometry; D047348:Hydrolyzable Tannins / Q000032:analysis / Q000494:pharmacology; D007502:Iron Chelating Agents / Q000032:analysis / Q000494:pharmacology; D015227:Lipid Peroxidation / Q000187:drug effects*; D051379:Mice; D010636:Phenols / Q000032:analysis / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D011422:Propionates; D012819:Sikkim; D012855:Sitosterols / Q000032:analysis; D013185:Squalene / Q000032:analysis / Q000494:pharmacology; D014810:Vitamin E / Q000032:analysis / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D003373:Coumaric Acids; D005419:Flavonoids; D047348:Hydrolyzable Tannins; D007502:Iron Chelating Agents; D010636:Phenols; D010936:Plant Extracts; D011422:Propionates; D012855:Sitosterols; D014810:Vitamin E; C025473:gamma-sitosterol; C040015:myricetin; D013185:Squalene; C004999:ferulic acid; C495469:p-coumaric acid