The alkaloids of Uncaria tomentosa micropropagated plantlets and root cultures were isolated and identified by NMR and mass spectrometry. Plantlets yielded pteropodine (1), isopteropodine (2), mitraphylline (3), isomitraphylline (4), uncarine F (5), speciophylline (6), rhynchophylline (7) and isorhynchophylline (8). In plantlets growing under continuous light, tetracyclic alkaloids 7 and 8 decreased from 20 ± 1.8 at 2 months to 2.2 ± 0.33 mg/g dry wt at 6 months, while the pentacyclic alkaloids 1-4 increased from 7.7 ± 1.4 to 15 ± 0.05 mg/g dry wt, supporting their biogenetic conversion. Micropropagated plantlets produced four times more alkaloids (27.6 ± 3.1 mg/g dry wt) than greenhouse plants. Plantlet roots yielded 3, 4, 8 and the glucoindole alkaloids 3α-dihydrocadambine (9) and dolichantoside (10), the last one not previously found in Uncaria.

Growth and alkaloid production in Uncaria tomentosa cell suspension cultures were studied in Murashige and Skoog medium supplemented with 10 microM 2,4-dichlorophenoxyacetic acid, 10 microM kinetin, and 58 mM sucrose for maintenance and with 10 microM indole-3-acetic acid, 10 microM kinetin, and 58 mM sucrose for production. A U. tomentosa pale Uth-3 cell line, cultured in the production medium, showed a reduced lag phase and a specific growth rate (mu) of 0.27 day(-1), while cells growing in the maintenance medium showed mu = 0.20 day(-1). U. tomentosa cells growing in the production medium produced monoterpenoid oxindole alkaloids (MOA) in amounts of 10.2 +/- 1.6 microg g(-1) dry weight (DW). The chemical profile of MOA produced by in vitro cell cultures was similar to that found in the plant. After 10 subcultures, maximum MOA production decreased to 2.0 +/- 0.7 microg g(-1) DW, while tryptamine alkaloids (TA) were produced with a maximum of 6.2 +/- 0.4 microg g(-1) DW. The increase of initial sucrose concentration up to 145 mM in the production medium enhanced the cell biomass by 3.2-fold (from 10.2 +/- 0.1 to 32.8 +/- 1.1 g DW L(-1)), reduced mu from 0.27 to 0.23 day(-1), and provoked a substantial accumulation of TA (23.1 +/- 4.7 microg g(-1) DW). A high sucrose concentration stimulated MOA production in the maintenance medium (2.7 +/- 0.5 microg g(-1) DW), even in the presence of 2,4-dichlorophenoxyacetic acid.

El ácido valproico es un fármaco antiepiléptico con más de 50 años de uso clínico. En la década pasada se descubrieron sus efectos anticancerígenos. El análisis de grupos de pacientes que utilizaron este fármaco durante años ha mostrado que disminuye la frecuencia de cáncer de cabeza y cuello. Estudios recientes evidencian el efecto anticáncer al combinar el ácido valproico con la quimioterapia, terapia biológica e inhibidores de sistemas antioxidantes, con resultados excepcionales. En esta revisión se analiza el metabolismo del ácido valproico y su aplicación contra el cáncer.