Title

 

Authors

V. Di Viesti
 
Doctorate School in Clinical and Experimental Medicine
Dept. of Biomedical Sciences, Section of Pharmacology - University of  Modena and Reggio Emilia, Italy

 

Abstract

Griffonia simplicifolia Baill. (fam. Cesalpinaceae) is a wooden climbing shrub native to West and Central Africa. In the traditional medicine of African countries, different parts of the plant (seeds, roots, leaves) are used for the treatment of different pathologies, including diarrhea, vomiting and stomachache (Ayensu, 1978). The seeds are reputed to exert an aphrodisiac activity, as well as to have antibiotic properties. Although scientific evidence of the plant pharmacological properties is still lacking, the modern therapeutic applications of Griffonia simplicifolia seed extract include the treatment of anxiety and depression, insomnia, migraine and headache, as well as the regulation of appetite leading to weight reduction in obese patients. These effects might be attributed to the high concentration in seeds of a serotonin precursor, 5-hydroxy-L-tryptophan (5-HTP), as reported by Lemaire and Adosraku (2002). 5-HT is a monoamine neurotransmitter in the mammalian CNS involved in the modulation of several essential bahavioral and physiological functions, such as mood, sleep and wakefulness, cognition, appetite, aggression, impulsivity, circadian rhytms, body temperature and sexual bahavior (Filip and Bader, 2009). Its depletion is recognized as a contributing factor in several disorders such as, anxiety (Kahn and Westenberg, 1985), major depression, schizophrenia, obesity and drug addiction (Filip and Bader, 2009). Therefore, medicinal plants containing a high concentration of 5-HTP, i.e. Griffonia simplicifolia, could represent a new therapeutic strategy for the treatment of serotonin-related disorders. In the present study we investigated the influence of the plant extract on sexual behavior in male rats. Griffonia simplicifolia seed extract, dosed at 25, 50 and 100 mg/kg, was acutely and subchronically (daily for 9 days) administered by oral gavage in male rats, thereafter which were submitted to the mating test with receptive females. After the acute treatment with the seed extract, a dose-dependent increase in mount latency was observed in treated animals in comparison with vehicle ones. A significant increase in intromission and ejaculation latencies was detected only in rats treated with the highest dose of 100 mg/kg. Furthermore the acute administration of Griffonia simplicifolia extract dosed at 50 and 100 mg/kg produced a significant increase in post-ejaculatory interval in comparison with controls. Mount and intromission frequency, as well, the percentage of mounting and ejaculating animals were not significantly influenced by the treatment with the extract. On the other hand, the subchronic treatment failed to exert a significant influence on copulatory behavior. Microdialysis technique was used to detect the extracellular levels of 5-HT and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in rat brain following the acute administration of the extract dosed at 100 mg/kg. In these experiments we found a dramatic increase in 5-HT and its metabolite 5-HIAA, which peaked at 90 and 120 min after the administration.

Ayensu, E.S., 1978. Medicinal plants of West Africa. Reference Publication, Michigan, USA.
Filip, M., Bader, M., 2009. Overview on 5-HT receptors and their role in physiology and pathology of the central nervous system. Pharmacol. Rep. 61, 761-777.
Kahn, R.S., Westenberg, H.G., 1985. L-5-hydroxytryptophan in the treatment of anxiety disorders. J. Affect. Disord. 8, 197-200.
Lemaire, P.A., Adosraku, R.K., 2002. An HPLC method for the direct assay of the serotonin precursor, 5-hydroxytrophan, in seeds of Griffonia simplicifolia. Phytochem. Anal. 13, 333-337.