title: Development of piperic acid derivatives from Piper nigrum as UV protection agents.
abstract: BACKGROUND
  There is a need for the discovery of novel natural and semi-synthetic sunscreen that is safe and effective. Piperine has a UV absorption band of 230-400 nm with high molar absorptivity. This compound has a high potential to be developed to sunscreen.
  
  
  OBJECTIVE
  This study develops new UV protection compounds from piperine by using chemical synthesis.
  
  
  METHODS
  Piperine was isolated from Piper nigrum L. (Piperaceae) fruits, converted to piperic acid by alkaline hydrolysis, and prepared as ester derivatives by chemical synthesis. The piperate derivatives were prepared as 5% o/w emulsion, and the SPF values were evaluated. The best compound was submitted to cytotoxicity test using MTT assay.
  
  
  RESULTS
  Piperic acid was prepared in 86.96% yield. Next, piperic acid was reacted with alcohols using Steglich reaction to obtain methyl piperate, ethyl piperate, propyl piperate, isopropyl piperate, and isobutyl piperate in 62.39-92.79% yield. All compounds were prepared as 5% oil in water emulsion and measured its SPF and UVA/UVB values using an SPF-290S analyzer. The SPF values (n = 6) of the piperate derivatives were 2.68 ± 0.17, 8.89 ± 0.46, 6.86 ± 0.91, 16.37 ± 1.8, and 9.68 ± 1.71. The UVA/UVB ratios of all compounds ranged from 0.860 to 0.967. Cytotoxicity of isopropyl piperate was evaluated using human skin fibroblast cells and the IC50 was equal to 120.2 μM.
  
  
  CONCLUSIONS
  From the results, isopropyl piperate is an outstanding compound that can be developed into a UV protection agent.
authors.affiliation: Faculty of Oriental Medicine, Rangsit University , Pathumthani , Thailand .
authors.forename: Piyapong
authors.initials: P
authors.lastname: Choochana
authors.forename: Jirapan
authors.initials: J
authors.lastname: Moungjaroen
authors.forename: Nathjanan
authors.initials: N
authors.lastname: Jongkon
authors.forename: Wandee
authors.initials: W
authors.lastname: Gritsanapan
authors.forename: Prasan
authors.initials: P
authors.lastname: Tangyuenyongwatana
mesh_terms: D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D019295:Computational Biology; D005231:Fatty Acids, Unsaturated / Q000302:isolation & purification* / Q000494:pharmacology* / Q000633:toxicity; D005347:Fibroblasts / Q000187:drug effects / Q000528:radiation effects; D006801:Humans; D006860:Hydrogen Bonding; D008958:Models, Molecular; D029222:Piper nigrum / Q000737:chemistry*; D012867:Skin / Q000166:cytology / Q000187:drug effects* / Q000528:radiation effects; D013056:Spectrophotometry, Ultraviolet; D013473:Sunscreening Agents / Q000302:isolation & purification* / Q000494:pharmacology* / Q000633:toxicity
chemical_list: D005231:Fatty Acids, Unsaturated; D013473:Sunscreening Agents; C000602012:isopropyl piperate; C017637:piperic acid
keywords: MTT assay; SPF; Steglich reaction; UVA; UVB; piperine; sunscreen