Background: Sustainable and commercial production of secondary metabolites is a critical issue when dealing with its clinical application. Efforts are still being made to look for biotic or abiotic elicitors with more efficient and universal effects on the improvement of secondary metabolites.

Objective: In order to evaluate the suitability of different biotic elicitors on P. harmala L. cell suspension cultures was established to enhance the &beta-carboline alkaloids (harmaline and harmine) production.

Methods: The elicitation of cell suspension cultures of Peganum harmala L. was done by adding various fungal mycelium homogenates (Aspergillus flavus, Alternaria alternate, Coriolus versicolor, Fusarium oxysporum, Mucor sp, Penicillium notatum, and Rhizopus stonifer), Casein hydrolysate and Saccharomyces cerevisiae at different concentrations. The cell cultures of P. harmala L. were subcultured on MS medium with optimal treatment of biotic elicitor. CAMAG analytical HPTLC system was used for estimation of harmaline and harmine after extraction of &beta-carboline alkaloids.

Results: The maximum harmine production (91.2±1.8 µg g^-1 DW) was observed at 1000 mg l^-1 S. cerevisiae in cell suspension culture of P. harmala L. (1.68 fold over than the control). Also the results showed that supplement of 75-100 mg l^-1 casein hydrolysate in cell cultures media increased biomass of cell culture and harmaline and harmine production (1.61 and 1.46 times over than the control, respectively).

Conclusion: The conclusion of the research showed that by applying biotic elicitors, we can reach to higher secondary metabolites (harmaline and harmine) in cell suspension culture of P. harmala L. We suggest future investigation on using other elicitors like bacterial extract or signal transduction compounds in cell suspension culture of P. harmala L. in order to increase the production of different kind of secondary metabolites.