title: The identities and anti-herpes simplex virus activity of Clinacanthus nutans and Clinacanthus siamensis.
abstract: OBJECTIVE
  To distinguish the difference among the Clinacanthus nutans (Burm. f.) Lindau (C. nutans) and Clinacanthus siamensis Bremek (C. siamensis) by assessing pharmacognosy characteristics, molecular aspect and also to evaluate their anti-herpes simplex virus (HSV) type 1 and type 2 activities.
  
  
  METHODS
  Macroscopic and microscopic evaluation were performed according to WHO Geneva guideline. Stomatal number, stomatal index and palisade ratio of leaves were evaluated. Genomic DNA was extracted by modified CTAB method and ITS region was amplified using PCR and then sequenced. Dry leaves were subsequently extracted with n-hexane, dichloromethane and methanol and antiviral activity was performed using plaque reduction assay and the cytotoxicity of the extracts on Vero cells was determined by MTT assay.
  
  
  RESULTS
  Cross section of midrib and stem showed similar major components. Leaf measurement index of stomatal number, stomatal index and palisade ratio of C. nutans were 168.32±29.49, 13.83±0.86 and 6.84±0.66, respectively, while C. siamensis were 161.60±18.04, 11.93±0.81 and 3.37±0.31, respectively. The PCR amplification of ITS region generated the PCR product approximately 700 bp in size. There were 34 polymorphisms within the ITS region which consisted of 11 Indels and 23 nucleotide substitutions. The IC50 values of C. nutans extracted with n-hexane, dichloromethane and methanol against HSV-1 were (32.05±3.63) µg/mL, (44.50±2.66) µg/mL, (64.93±7.00) µg/mL, respectively where as those of C. siamensis were (60.00±11.61) µg/mL, (55.69±4.41) µg/mL, (37.39±5.85) µg/mL, respectively. Anti HSV-2 activity of n-hexane, dichloromethane and methanol C. nutans leaves extracts were (72.62±12.60) µg/mL, (65.19±21.45) µg/mL, (65.13±2.22) µg/mL, respectively where as those of C. siamensis were (46.52±4.08) µg/mL, (49.63±2.59) µg/mL, (72.64±6.52) µg/mL, respectively.
  
  
  CONCLUSIONS
  The combination of macroscopic, microscopic and biomolecular method are able to authenticate these closely related plants and both of them have a potency to be an anti-HSV agent.
authors.affiliation: College of Public Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Paween
authors.initials: P
authors.lastname: Kunsorn
authors.forename: Nijsiri
authors.initials: N
authors.lastname: Ruangrungsi
authors.forename: Vimolmas
authors.initials: V
authors.lastname: Lipipun
authors.forename: Ariya
authors.initials: A
authors.lastname: Khanboon
authors.forename: Kanchana
authors.initials: K
authors.lastname: Rungsihirunrat
authors.forename: Wanna
authors.initials: W
authors.lastname: Chaijaroenkul
mesh_terms: D027901:Acanthaceae / Q000737:chemistry* / Q000235:genetics; D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology*; D035264:Flowers / Q000737:chemistry / Q000166:cytology / Q000235:genetics; D018259:Herpesvirus 1, Human / Q000187:drug effects; D018258:Herpesvirus 2, Human / Q000187:drug effects; D006801:Humans; D010641:Phenotype; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry / Q000166:cytology / Q000235:genetics; D018139:Simplexvirus / Q000187:drug effects*; D010948:Viral Plaque Assay; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; D010936:Plant Extracts
keywords: Biomolecular analysis; Clinacanthus nutans; Clinacanthus siamensis; Herpes simplex virus; Internal transcribed spacer; Microscopic analysis; Plaque reduction assay