Root Cultures of Linum Species Section Syllinum as Rich Sources of 6-Methoxypodophyllotoxin

professor of Pharmacognosy, Tehran Faculty of Pharmacy, Tehran on the occasion of his birthday Linum spp. from section Syllinum are promising for the production of aryltetralin lignans like podophyllotoxin (PTOX) and 6-methoxypodophyllotoxin (MPTOX). MPTOX is a PTOX congener that has cytotoxic activity comparable with PTOX. In this study root cultures of Linum Bungei from section Dasyllinum, L. strictum from section Linastrum, L. album, L. mucronatum ssp. mucronatum and L. nodiflorum from section Syllinum were established and their MPTOX levels were investigated in 1000 ml flasks. Root cultures of L. mucronatum ssp. mucronatum and L. nodiflorum were used to examine cell growth and production of MPTOX during a culture period of 36 days in 250 ml flasks. Considerable amounts of MPTOX in root cultures (1000 ml flasks) of L. album (6 mg/100 g DW), L. mucronatum ssp. mucronatum (770 mg/100 g DW) and L. nodiflorum (91 mg/100 g DW) were detected while it wasn't detected in root cultures of L. Bungei and L. strictum. In time course experiments, the maximum amount of MPTOX in L. nodiflorum root culture was at day 16 with 480 mg/ 100 g DW and the maximum amount of MPTOX in L. mucronatum ssp. mucronatum root culture was at day 12 with 130 mg/100 g DW. The results showed that root cultures of Linum species from section Syllinum are rich sources of MPTOX and since this lignan has remarkable cytotoxic activity, it can be used as a precursor for the production of antitumor agents

Quantification of Aryltetralin Lignans in Linum album Organs and In Vitro Cultures: Lignans from Linum album

Aprocedure was developed for rapid in vitro germination of Linum album seeds by scarification and exposing to gibberellic acid (GA3) and kinetin (Kn). Concentrations of podophyllotoxin (PTOX) and related aryltetralin lignans α-peltatin, β-peltatin, 5’-demethoxy-6-methoxypodophyllotoxin and 6-methoxypodophyllotoxin (MPTOX) in L. album fresh plant organs were determined by HPLC. A degree of variation was observed in lignan content in different plant parts and growth stages. It was found that PTOX is predominant in productive organs and leaves. The highest amount of PTOX (0.651 mg/100g dry wt.) and MPTOX (0.670 mg/100g dry wt.) and the total quantified lignans were found in the capsules. In vitro cultures were studied for lignans followed by high productive cell line selection. Calli cultures were more productive for MPTOX than PTOX, while suspension cells accumulate comparable amounts of PTOX and MPTOX. The highest amount of PTOX (0.301% mg/g dry wt.) was found in suspension originated immobilized cultures

Biosynthesis of podophyllotoxin in Linum album cell cultures

Cell cultures of Linum album Kotschy ex Boiss. (Linaceae) showing high accumulation of the lignan podophyllotoxin (PTOX) were established. Enzymological studies revealed highest activities of phenylalanine ammonia-lyase, cinnamyl alcohol dehydrogenase, 4-hydroxycinnamate:CoA ligase and cinnamoyl-CoA:-NADP oxidoreductase immediately prior to PTOX accumulation. To investigate PTOX biosynthesis, feeding experiments were performed with [2- 13 C]3¢,4¢-dimethoxycinnamic acid, [2-13 C]3¢,4¢-methylenedioxycinnamic acid (MDCA), [2-13C]3¢,4¢,5¢-trimethoxycinnamic acid,[2- 13C]sinapic acid, [2-13C]- and [2,3-13C2]ferulic acid.Analysis of the metabolites by HPLC coupled to tandem mass spectrometry revealed incorporation of label from ferulic acid into PTOX and deoxypodophyllotoxin (DOP). In addition, MDCA was also unambiguously incorporated intact into PTOX. These observations suggest that in L. album both ferulic acid and methylenedioxy-substituted cinnamic acid can be incorporated into lignans. Furthermore, it appears that, in this species, the hydroxylation of DOP is a rate-limiting point in the pathway leading to PTOX

Metabolic profiling of lignan variability in Linum species of section Syllinum native to Bulgaria

Lignans in eighteen samples of Linum species (L. tauricum ssp. tauricum, serbicum, bulgaricum and linearifolium; L. elegans; L. flavum ssp. sparsiflorum, L. capitatum var. laxiflorum), all members of the section Syllinum occurring in Bulgaria, were analysed by HPLC-ESI/MS and HPLC-UV/DAD. The ESI/MS fragmentation pathways recently established for aryltetralin lignans are now extended to ester and glycoside derivatives. In total, 22 different lignans, mainly of the aryltetralin type, were identified. 6-Methoxypodophyllotoxin and its glucoside were present as major constituents in all samples. Differences between the investigated taxa were observed especially with respect to the accumulation of 6-deoxy-7-hydroxy-aryltetralins such as podophyllotoxin and of 6-hydroxy-7-deoxy-aryltetralin lignans of the peltatin type. The distribution of aryltetralin lignans with different oxygenation patterns in the various samples, and correlations between the chemical data and the molecular phylogeny based on an analysis of ITS sequences of the investigated species are discussed