Comparing aryltetralin lignans production by adventitious roots from three Linum species

Plant secondary metabolism represents a network of chemical signals, known as secondary metabolites (SMs), which connect the plant with its environment. Among the wide diversity of plant SMs, lignans are plant phenols deriving from phenylpropanoids. Lignans play an important role in plant defence, conferring protection against herbivores and microorganisms, and show antibacterial, antiviral and antifungal properties. Moreover, they show a wide range of applications as components of food, textiles and medicine. These compounds have attracted the attention of scientists for their potent antiviral and antineoplastic properties. In particular, the aryltetralin-lignans (ATL) have received much attention since the discovery of podophyllotoxin, the most representative compounds of this class well-known for its anticancer properties and used as starting compound for the semi-synthesis of leading anticancer drugs (etoposide, teniposide). It is currently produced largely from Podophyllum hexandrum and P. peltatum, slow-growing endangered species of the Berberidaceae. Although several plant species are known to synthetize podophyllotoxin and its derivatives, Linum species seem to be particularly promising because they can accumulate substantial amounts of these compounds and can be easily grown in fields or cultivated as cell cultures. In this work we have used a biotechnological approach, based on in vitro tissue cultures, to enhance lignans production. In particular, we obtained adventitious roots cultures from Syllinum section such as: Linum mucronatum, Linum flavum and Linum dolomiticum. In this study we focused mainly on the root growth kinetics and on the production of aryltetralin lignans. Different elicitation strategies were also applied to enhance ATLs production. In particular, we focused on HPLC and NMR fingerprint to compare the productivity for of podophyllotoxin, 6-methoxypodophyllotoxin and 6-methoxypodophyllotoxin 4-?-D glucoside among the different species.