Background: Plant lectins have shown promising biological activities in the central nervous system
Objective: This study evaluated the effect of DAL, a lectin isolated from the seeds of the Dioclea altissima species,
having binding affinity to D-glucose or D-mannose residues, on mice behavior.
Methods: Mice (n=6/group) were treated (i.p.) with DAL (0.25, 0.5 or 1 mg/kg) or vehicle and subjected to several
tests (open field/OFT, marble-burying/MBT, hole-board/HBT, elevated plus maze/PMT, tail suspension/
TST, forced swimming/FST or rotarod/RRT). Pizotifen, cyproheptadine, flumazenil, L-NAME, 7-NI, Larginine
or yohimbine were administered 15 min before DAL (0.5 mg/kg) and the animals were evaluated on
PMT. It was also verified whether the DAL effect depended on its structural integrity and ability to interact with
Results: The results showed there were no neurobehavioral changes in the mice at the RRT, FST and locomotion
in the OFT. DAL (0.25, 0.5 or 1 mg/kg) increased the behavior of grooming and rearing in the OFT, head dips in
the HBT, pedalling in the TST and decreased the number of marbles hidden in the MBT. In the PMT, DAL (0.25,
0.5 and 1 mg/kg) and Diazepam increased the frequency of entries in the open arms and the time of permanence
in the open arms without affecting the locomotor activity. The effect of DAL was dependent on carbohydrate
interaction and protein structure integrity and it prevented by pizotifen, cyproheptadine, flumazenil, L-NAME and
7-NI, but not by L-arginine or yohimbine.
Conclusion: DAL was found to have an anxiolytic-like effect mediated by the 5-HT and GABAergic receptors
and NO pathway.