title: Antioxidant and cytoprotective activities of Piper betle, Areca catechu, Uncaria gambir and betel quid with and without calcium hydroxide.
abstract: BACKGROUND
  Betel quid chewing is a popular habit in Southeast Asia. It is believed that chewing betel quid could reduce stress, strengthen teeth and maintain oral hygiene. The aim of this study was to investigate the antioxidant and cytoprotective activities of each of the ingredients of betel quid and compared with betel quid itself (with and without calcium hydroxide). The correlation of their cytoprotective and antioxidant activities with phenolic content was also determined.
  
  
  METHODS
  Five samples (betel leaf, areca nut, gambir, betel quid and betel quid containing calcium hydroxide) were extracted in deionized distilled water for 12 hours at 37°C. Antioxidant activities were evaluated for radical scavenging activity using DPPH assay, ferric reducing activity using FRAP assay and lipid peroxidation inhibition activity using FTC assay. Total phenolic content (TPC) was determined using Folin-Ciocalteu procedure. Phenolic composition was analyzed using LC-MS/MS. Cytoprotective activity towards human gingival fibroblast cells was examined using MTT assay.
  
  
  RESULTS
  Among the ingredients of betel quid, gambir demonstrated the highest antioxidant (DPPH - IC50 = 6.4 ± 0.8 μg/mL, FRAP - 5717.8 ± 537.6 μmol Fe(II)/mg), total phenolic content (TPC - 1142.5 ± 106.8 μg TAE/mg) and cytoprotective (100.1 ± 4.6%) activities. Betel quid when compared with betel quid containing calcium hydroxide has higher antioxidant (DPPH - IC50 =59.4 ± 4.4 μg/mL, FRAP - 1022.2 ± 235.7 μmol Fe(II)/mg), total phenolic content (TPC - 140.0 ± 22.3 μg TAE/mg), and cytoprotective (113.5 ± 15.9%) activities. However, all of the five samples showed good lipid peroxidation inhibition compared to vitamin E. LC-MS/MS analysis revealed the presence of quinic acid as the major compound of gambir and betel quid. A positive correlation was observed between TPC and radical scavenging (r = 0.972), reducing power (r = 0.981) and cytoprotective activity (r = 0.682).
  
  
  CONCLUSIONS
  The betel quid has higher TPC, and antioxidant and cytoprotective activities than betel quid with calcium hydroxide. The quinic acid in betel quid may play an important role in the oral health protection.
authors: Nordin Nur
authors: NN
authors: Sazwi
authors: Thurairajah
authors: T
authors: Nalina
authors: Department of Oral Biology, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia. zubaidar@um.edu.my.
authors: Zubaidah Haji
authors: ZH
authors: Abdul Rahim
mesh_terms: D000704:Analysis of Variance; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology*; D001114:Areca / Q000737:chemistry*; D002126:Calcium Hydroxide / Q000737:chemistry*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D005881:Gingiva / Q000166:cytology; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D015227:Lipid Peroxidation / Q000187:drug effects; D009754:Nuts / Q000737:chemistry; D010084:Oxidation-Reduction / Q000187:drug effects; D010636:Phenols / Q000737:chemistry; D031721:Piper betle / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D032070:Uncaria / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D010636:Phenols; D010936:Plant Extracts; D006861:Hydrogen Peroxide; D002126:Calcium Hydroxide