title: Protective effect of Salacia oblonga against tobacco smoke-induced DNA damage and cellular changes in pancreatic β-cells.
abstract: BACKGROUND
  Tobacco smoking generates a tremendous amount of free radicals that induce oxidative stress (OS) in diabetics (pancreatic islet cells are defective). Salacia oblonga Wall. (Celastraceae) is a proven antioxidant and antidiabetic plant whose mechanism of action is yet to be explored.
  
  
  OBJECTIVE
  The present study focuses on the protective ability of S. oblonga in tobacco smoke-induced oxidatively stressed pancreatic β-cell line.
  
  
  METHODS
  The RINm5f cell line was exposed to tobacco smoke concentrate (TSC) (0.5-10%, 24 h), plant extract (1-75 µg/ml, 3 h), and their combinations. Cell viability was determined through MTT assay. Microscopic analysis was carried out in unstained and nonyl acridine orange-stained cells. The effect of toxic doses of TSC on DNA integrity was analyzed through DNA fragmentation assay. The TSC-induced nitric oxide generation was determined spectrophototmetrically. The expression of anti-apoptotic protein Bcl-X under the above treatment conditions was carried out through RT-PCR.
  
  
  RESULTS
  The LD50 dose for TSC was found to be 1% TSC. Salacia oblonga extracts (10 and 15 µg/ml) were found to be optimum safe doses that significantly increased cell viability and decreased the nitric oxide production in TSC-treated cells. Pre-treatment with plant extract suppressed apoptosis through probable increase in the expression of anti-apoptotic protein Bcl-X in TSC-treated cells. Thus, the overall efficiency of plant extract in recovering cellular damage was proven.
  
  
  CONCLUSIONS
  The results suggest that TSC-induced cellular alterations are related to rise in nitric oxide and Bcl-X mRNA expression and propose that S. oblonga may confer significant cytoprotection against OS-mediated injury in β-cells.
authors.affiliation: a Department of Biotechnology , Jaypee Institute of Information Technology , Noida , Uttar Pradesh , India.
authors.forename: Sujata
authors.initials: S
authors.lastname: Basu
authors.affiliation: a Department of Biotechnology , Jaypee Institute of Information Technology , Noida , Uttar Pradesh , India.
authors.forename: Mamta
authors.initials: M
authors.lastname: Pant
authors.affiliation: a Department of Biotechnology , Jaypee Institute of Information Technology , Noida , Uttar Pradesh , India.
authors.forename: R
authors.initials: R
authors.lastname: Rachana
mesh_terms: D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D004249:DNA Damage / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D050417:Insulin-Secreting Cells / Q000187:drug effects* / Q000473:pathology; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D020011:Protective Agents / Q000302:isolation & purification / Q000494:pharmacology; D051381:Rats; D049918:Salacia; D012906:Smoke / Q000009:adverse effects*; D014026:Nicotiana
chemical_list: D010936:Plant Extracts; D020011:Protective Agents; D012906:Smoke
keywords: Bcl-X; mitochondria; nitric oxide