• Basil
• elicitation
• methyl jasmonate
• Rosmarinic acid
• stress markers

One of the plant’s most important secondary metabolite is the Rosmarinic Acid (RA), which mainly acts as antioxidant, but also possess promising biological activities as improve the cognitive performance, prevent the development of Alzheimer’s disease, cardio-protective effects and reduce the severity of kidney diseases and cancer chemoprevention.
RA is one of the first secondary metabolites produced in plant cell cultures in extremely high yields. Several studies demonstrate that RA production has been higher in in vitro systems than in natural conditions. Indeed factors like phytohormones and/or the presence of precursors from biosynthetic pathway affect secondary metabolites accumulation; nevertheless, elicitation is the most effective process to enhance the synthesis.
Basil (Ocimum basilicum L.,), is a multi-functional annual herb with aromatic, antiviral, antioxidant and antibacterial properties. Basil is also a source of phenolic compounds, in particular RA. Into the basil cultivars, Genovese basil (GEN) is one of the most popular cultivar for culinary, while Dark opal basil (DO) is grown as much for its decorative appeal as for its culinary value.
The present study analyzed the increase of RA production in two cultivars of O. basilicum (GEN and DO) that were elicitated with Methyl jasmonate (MeJA) at different concentration. Tests were run both in vitro and in vivo systems in order to compare the behavior of the green and red basil in the production of the secondary metabolites. For the in vitro culture was tested: traditional (Magenta vessels), cellular (callus tissue) and industrial (RITA® bioreactor) micropropagation. Also was tested a combination between in vivo-in vitro culture (Falcon tubes) and an in vivo culture (greenhouse).
In the experiment was used 0.05, 0.1, 0.2, 0.5 and 1mM of MeJA to induce the elicitation. The elicitor was sprayed on shoots leaves cultivated in semisolid or solid culture medium and directly added to the liquid culture medium. Sampling was made at 24, 48, 72 and 96 hours after elicitation. The treatments were compared using the two-way ANOVA test.
Using phenol index as a quick screening, was found significant difference (P<0.05) in the production of phenolic acid content after elicitation. In the comparison among systems and cultivars, the best result was achieved with GEN cultured in RITA® bioreactor, after 48h of elicitation with 0.1mM of MeJA. The analysis of RA by HPLC revealed an increase of 2.18-fold over the respective control, and 9.91-fold in comparison with greenhouse control-plants.
On the other hand, the study of the relationship between the in vitro environment and the production of RA showed different results. Stress markers such as proline and carotenoids, showed a content increase, while photosynthetic activity decreased in RITA® bioreactor, due to the hyperhydric state of shoots. About chlorophyll, the content in RITA® bioreactor of chlorophyllb increased as an effort to delays the senescence, but could also be a response to light intensity due to the color of containers. In Abscisic acid (ABA) content, the results showed an increase in all in vitro systems compared with the combined system (Falcon-tubes). The high production of ABA could be attributed to the use of 6-benzylaminopurine in in vitro culture medium, as a response to protect the cells against the cytokinin-induced death.