title: Antioxidant, antibacterial, cytotoxic, and apoptotic activity of stem bark extracts of Cephalotaxus griffithii Hook. f.
abstract: BACKGROUND
  Cephalotaxus spp. are known to possess various therapeutic potentials. Cephalotaxus griffithii, however, has not been evaluated for its biological potential. The reason may be the remoteness and inaccessibility of the habitat where it is distributed. The main aim of this study was to: (1) evaluate multiple biological potentials of stem bark of C. griffithii, and (2) identify solvent extract of stem bark of C. griffithii to find the one with the highest specific biological activity.
  
  
  METHODS
  Dried powder of stem bark of C. griffithii was exhaustively extracted serially by soaking in petroleum ether, acetone and methanol to fractionate the chemical constituents into individual fractions or extracts. The extracts were tested for total phenolic and flavonoid content, antioxidant (DPPH radical scavenging, superoxide radical scavenging, and reducing power models), antibacterial (disc diffusion assay on six bacterial strains), cytotoxic (MTT assay on HeLa cells), and apoptotic activity (fluorescence microscopy, DNA fragmentation assay, and flow cytometry on HeLa cells).
  
  
  RESULTS
  Among the three extracts of stem bark of C. griffithii, the acetone extract contained the highest amount of total phenolics and flavonoids and showed maximum antioxidant, antibacterial, cytotoxic (IC50 of 35.5 ± 0.6 μg/ml; P < 0.05), and apoptotic (46.3 ± 3.6% sub-G0/G1 population; P < 0.05) activity, followed by the methanol and petroleum ether extracts. However, there was no significant difference observed in IC50 values (DPPH scavenging assay) of the acetone and methanol extracts and the positive control (ascorbic acid). In contrast, superoxide radical scavenging assay-based antioxidant activity (IC50) of the acetone and methanol extracts was significantly lower than the positive control (P < 0.05). Correlation analysis suggested that phenolic and flavonoid content present in stem bark of C. griffithii extracts was responsible for the high antioxidant, cytotoxic, and apoptotic activity (P < 0.05).
  
  
  CONCLUSIONS
  Stem bark of C. griffithii has multiple biological effects. These results call for further chemical characterization of acetone extract of stem bark of C. griffithii for specific bioactivity.
authors.affiliation: Institute of Bioresources and Sustainable Development, Department of Biotechnology, Government of India, Takyelpat Institutional Area, Imphal 795001, Manipur, India. nayan.ibsd@nic.in
authors.forename: Dinesh Singh
authors.initials: DS
authors.lastname: Moirangthem
authors.forename: Narayan Chandra
authors.initials: NC
authors.lastname: Talukdar
authors.forename: Naresh
authors.initials: N
authors.lastname: Kasoju
authors.forename: Utpal
authors.initials: U
authors.lastname: Bora
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology / Q000627:therapeutic use*; D000975:Antioxidants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D032483:Cephalotaxus / Q000737:chemistry*; D005419:Flavonoids / Q000032:analysis / Q000494:pharmacology / Q000627:therapeutic use; D006367:HeLa Cells; D006801:Humans; D010636:Phenols / Q000032:analysis / Q000494:pharmacology / Q000627:therapeutic use; D008517:Phytotherapy; D024301:Plant Bark; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use; D018547:Plant Stems
chemical_list: D000900:Anti-Bacterial Agents; D000972:Antineoplastic Agents, Phytogenic; D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts