title: Prenylated caged xanthones: chemistry and biology.
abstract: BACKGROUND
  Prenylated caged xanthones are "privileged structure" characterized by the presence of the unusual 4-oxo-tricyclo[4.3.1.0(3,7)]dec-8-en-2-one scaffold. The natural sources of these compounds confines mainly in the Garcinia genus in the family of Guttiferae. Gambogic acid is the most abundant substance and most of the studies have been done on this compound, particularly as a new potential antitumor agent. The history, sources, structural diversity, and biological activities of these compounds are covered.
  
  
  OBJECTIVE
  This review is written with the intention to provide additional aspects from what have been published of prenylated caged xanthones, including history, sources, structural diversity, and biological activities.
  
  
  METHODS
  This review has been compiled using information from a number of reliable references mainly from major databases including SciFinder, ScienceDirect, and PubMed.
  
  
  RESULTS
  More than 120 prenylated caged xanthones have been found in the plant genera Garcinia, Cratoxylum, and Dascymaschalon. These compounds exhibited various potentially useful biological activities such as anticancer, anti-HIV-1, antibacterial, anti-inflammatory, and neurotrophic activities.
  
  
  CONCLUSIONS
  Prenylated caged xanthones, both naturally occurring and synthetic analogues, have been identified as promising bioactive compounds, especially for anticancer agents. Gambogic acid has been demonstrated to be a highly valuable lead compound for antitumor chemotherapy. The structure activity relationship (SAR) study of its analogues is still the subject of intensive research. Apoptosis cytotoxic mechanism has been identified as the major pathway. Research on the delineation of the in-depth mechanism of action is still on-going. Analogues of gambogic acid had been identified to be effective against a rare and special form of liver cancer, cholangiocarcinoma for which currently there is no chemotherapeutic treatment available.
authors.affiliation: Department of Pharmacognosy and The Center of Excellence for Innovation in Chemistry, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand.
authors.forename: Natthinee
authors.initials: N
authors.lastname: Anantachoke
authors.forename: Patoomratana
authors.initials: P
authors.lastname: Tuchinda
authors.forename: Chutima
authors.initials: C
authors.lastname: Kuhakarn
authors.forename: Manat
authors.initials: M
authors.lastname: Pohmakotr
authors.forename: Vichai
authors.initials: V
authors.lastname: Reutrakul
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D006801:Humans; D009369:Neoplasms / Q000188:drug therapy / Q000473:pathology; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D054876:Prenylation; D013329:Structure-Activity Relationship; D044004:Xanthones / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D010936:Plant Extracts; D044004:Xanthones; C052659:gambogic acid