Evaluation of Alkaloids Isolated from Ruta graveolens as Photosynthesis Inhibitors

Molecules. 2018 Oct 19;23(10):2693. doi: 10.3390/molecules23102693.


Eight alkaloids (18) were isolated from Ruta graveolens, and their herbicide activities were evaluated through in vitro, semivivo, and in vivo assays. The most relevant results were observed for Compounds 5 and 68 at 150 μM, which decreased dry biomass by 20% and 23%, respectively. These are significant results since they presented similar values with the positive control, commercial herbicide 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). Based on the performed assays, Compound 5 (graveoline) is classified as an electron-transport inhibitor during the light phase of photosynthesis, as well as a plant-growth regulator. On the other hand, Compounds 68 inhibited electron and energy transfers, and are also plant-growth inhibitors. These phytotoxic behaviors based on acridone and quinolone alkaloids may serve as a valuable tool in the further development of a new class of herbicides since natural products represent an interesting alternative to replace commercial herbicides, potentially due their low toxicity.

Keywords: Chl a fluorescence; Hill reaction inhibitors; Ruta graveolens; acridone alkaloids; photosystem II.

MeSH terms

  • Alkaloids / chemistry
  • Alkaloids / isolation & purification*
  • Alkaloids / pharmacology
  • Biomass
  • Diuron / pharmacology
  • Electron Transport
  • Herbicides / pharmacology
  • Methoxsalen / analogs & derivatives*
  • Methoxsalen / chemistry
  • Methoxsalen / isolation & purification
  • Methoxsalen / pharmacology
  • Photosynthesis / drug effects*
  • Ruta / chemistry*


  • Alkaloids
  • Herbicides
  • graveoline
  • Diuron
  • Methoxsalen