**5. Elicitors**

To achieve secondary metabolite production, elicitation is one of the most important strategies and is used to increase productivity; it takes place through the addition In Vitro *Cultures for the Production of Secondary Metabolites DOI: http://dx.doi.org/10.5772/intechopen.101880*

**Figure 4.**

*Classification of elicitor based on different features.*

of compounds called elicitors—they can be defined as stress-inducing compounds that induce or improve biosynthesis of specific compounds when a specific amount is applied to a living system [52, 53].

Elicitors can be biotic, such as jasmonic acid, hydrolyzed casein, cellulase, macerozyme, yeast extract, fungal extract, chitin; in addition, chemical compounds usually synthesized from pathogens; abiotic elicitors that include nonorganic substances and can be divided into physical, chemical, and hormonal factors (**Figure 4**) [53, 54].
