Purpose. In a continuation of our search for novel antifungal compounds from higher plants, the standard extract of the bark of Pithecellobium racemosum was found to have good activity against important AIDS-related opportunistic yeasts. Methods. The extract was subjected to bioguided fractionation using silica gel column chromatography which led to purification of triterpene glycosides. The structures of these compounds were determined by a combination of spectroscopic (IR, NMR, HRMS) and chemical methods. Results. Compound 1 is a new glycoside, 3-O[α-L-arabinopyranosyl (1-2)][α-L arabinopyranosyl (1-6)]2-acetoamido-2-deoxy-β-D-glucopyranosyl oleanolic acid and Compound 2 was identified as the known compound 3-O-[α-L-arabinopyranosyl(1-2)α-L-arabinopyranoysl (1-6)] 2-acetamido-2-deoxy-β-D-glucopyranosyl echinocystic acid. Conclusions. Compound 1 is a new glycoside, 3-O-[α-L-arabinopyranosyl (1-2)]α-L-arabinopyranosyl (1-6)]-2-acetoamido-2-deoxy-β-D-glucopyranosyl oleanolic acid and exhibits moderate antifungal activity against T. mentogrophytes, C. albicans and S. cerevisiae with MIC values of 6.25, 12.5 and 12.5 mu g/ml respectively.

antifungal, triterpene glycoside, oleanolic acid, Pithecellobium racemosum, carbon-13C NMR

• Compound ID: 25618
  

  a-L-Arap-(1-2)-a-L-Arap-(1-6)-b-D-GlcpNAc-(1-3)-Echinocystic

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  Structure type: oligomer
  Compound class: saponin glycoside
  Reference(s) to other database(s): CCSD:29769, CBank-STR:5956
  
   
  
  Pithecellobium racemosum (M), Albizia anthelmintica
  CSDB ID 60515 (all data & tools)
• Compound ID: 28047
  

  a-L-Arap-(1-2)-a-L-Arap-(1-6)-b-D-GlcpNAc-(1-3)-Oleanolic

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  Structure type: oligomer ; 922 [M-H]-
  C48H77NO16
  Compound class: saponin glycoside
  
   
  
  Pithecellobium racemosum (M)
  CSDB ID 60514 (all data & tools)