title: Antileptospiral activity of xanthones from Garcinia mangostana and synergy of gamma-mangostin with penicillin G.
abstract: BACKGROUND
  Leptospirosis, one of the most widespread zoonotic infectious diseases worldwide, is caused by spirochetes bacteria of the genus Leptospira. The present study examined inhibitory activity of purified xanthones and crude extracts from Garcinia mangostana against both non-pathogenic and pathogenic leptospira. Synergy between γ-mangostin and penicillin G against leptospires was also determined.
  
  
  METHODS
  Minimal inhibitory concentrations (MIC) of crude extracts and purified xanthones from G. mangostana and penicillin G for a non-pathogenic (L. biflexa serovar Patoc) and pathogenic (L. interrogans serovar Bataviae, Autumnalis, Javanica and Saigon) leptospires were determined by using broth microdilution method and alamar blue. The synergy was evaluated by calculating the fractional inhibitory concentration (FIC) index.
  
  
  RESULTS
  The results of broth microdilution test demonstrated that the crude extract and purified xanthones from mangosteen possessed antileptospiral activities. The crude extracts were active against all five serovars of test leptospira with MICs ranging from 200 to ≥ 800 μg/ml. Among the crude extracts and purified xanthones, garcinone C was the most active compound against both of pathogenic (MIC =100 μg/ml) and non-pathogenic leptospira (MIC = 200 μg/ml). However, these MIC values were higher than those of traditional antibiotics. Combinations of γ-mangostin with penicillin G generated synergistic effect against L. interrogans serovars Bataviae, Autumnalis and Javanica (FIC = 0.52, 0.50, and 0.04, respectively) and no interaction against L. biflexa serovar Patoc (FIC =0.75). However, antagonistic activity (FIC = 4.03) was observed in L. interrogans serovar Saigon.
  
  
  CONCLUSIONS
  Crude extracts and purified xanthones from fruit pericarp of G. mangostana with significant antibacterial activity may be used to control leptospirosis. The combination of xanthone with antibiotic enhances the antileptospiral efficacy.
authors.forename: Weeranuch
authors.initials: W
authors.lastname: Seesom
authors.forename: Amornmart
authors.initials: A
authors.lastname: Jaratrungtawee
authors.forename: Sunit
authors.initials: S
authors.lastname: Suksamrarn
authors.forename: Chantana
authors.initials: C
authors.lastname: Mekseepralard
authors.forename: Piniti
authors.initials: P
authors.lastname: Ratananukul
authors.forename: Wasana
authors.initials: W
authors.lastname: Sukhumsirichart
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004357:Drug Synergism; D005638:Fruit; D029762:Garcinia mangostana / Q000737:chemistry*; D041743:Herb-Drug Interactions; D006801:Humans; D007919:Leptospira / Q000187:drug effects*; D007922:Leptospirosis / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D010400:Penicillin G / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology*; D044004:Xanthones / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D044004:Xanthones; C000596092:garcinone C; D010400:Penicillin G; C021053:mangostin