Constituents of Azadirachta indica: isolation and structure elucidation of a new antibacterial tetranortriterpenoid, mahmoodin, and a new protolimonoid, naheedin

J Nat Prod. 1992 Mar;55(3):303-10. doi: 10.1021/np50081a005.

Abstract

Mahmoodin [1], a new limonoid, has been isolated from Azadirachta indica (neem) oil, along with seven known tetranortriterpenoids, azadirone, epoxyazadiradione, nimbin, gedunin, azadiradione, deacetylnimbin, and 17-hydroxyazadiradione. A new protolimonoid, naheedin [3], has been obtained from the neem fruits along with azadirachtol. Their structures have been elucidated through chemical and spectral analyses including 2D nmr studies. The absolute configuration of 1 was established by comparison of its cd spectrum with those of the known tetranortriterpenoids. Mahmoodin showed significant antibacterial activity against various Gram-positive and Gram-negative organisms. Four hydrocarbons, icosane, docosane, 2-methyltricosane, and docosene, have also been identified by gc-ms of the EtOH extract of the fruit coats. Only docosane has earlier been reported from neem, while the remaining three are unreported from this plant.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / chemistry*
  • Anti-Bacterial Agents / pharmacology
  • Asia
  • Bacteria / drug effects
  • Gas Chromatography-Mass Spectrometry
  • Limonins*
  • Magnetic Resonance Spectroscopy
  • Microbial Sensitivity Tests
  • Molecular Conformation
  • Plants, Medicinal / chemistry*
  • Triterpenes / chemistry*
  • Triterpenes / pharmacology

Substances

  • Anti-Bacterial Agents
  • Limonins
  • Triterpenes
  • naheedin
  • mahmoodin