Cryopreservation of Cat’s Claw (<i>Uncaria tomentosa</i>)

Abstract

Uncaria tomentosa presents tomentum that resembles cat’s claws, hence its common name, is a plant that produces various secondary metabolites that are traditionally used in alternative medicine. The natural distribution of this species has been affected by indiscriminate harvesting from its habitat. In the present research, cryopreservation (liquid nitrogen, LN, -196&degC) was evaluated as an option for ex situ conservation of this species. The following techniques were evaluated: vitrification and encapsulation-dehydration of apices, vitrification of cell suspensions, and seed desiccation and vitrification. Preculture conditions and exposure times to LS and PVS2 were evaluated. Apex survival was the highest (82%) with preculture in 0.25 M sucrose followed by incubation for 20 and 30 min in LS and PVS2, respectively, prior to cooling in LN. The encapsulation-dehydration technique was evaluated by using sucrose preculture and different capsule moisture contents. Survival of apices cooled in LN was not significantly different between treatments and varied from 31.8% to 52.9% for capsule moisture contents between 22.7% and 20.3%. For cell suspensions precultured in 0.5 M sucrose, cell multiplication and formation of calli with very good appearance were observed in 61.1% of the cultures following vitrification. For cryopreservation of seeds, germination was 89.5% using the desiccation technique and 67.6% to78.1% using vitrification.