Cipura paludosa (Iridaceae), a native plant widely distributed in the north of Brazil, is used in
traditional medicine as an anti-inflammatory and
analgesic agent, against
tuberculosis and gonorrhoea and for regulation of menstrual flow. However, scientific studies on the pharmacological properties of C. paludosa are scarce. We have examined the potential protective effects of the ethanolic extract of C. paludosa against methyl
mercury (MeHg)-induced neurotoxicity in adult mice. MeHg was diluted in
drinking water (40 mg/l, freely available) and the ethanolic C. paludosa extract (CE) was diluted in a 150 mM NaCl
solution and administered by gavage (10 and 100 mg/kg
body weight, respectively, twice a day). Because treatment lasted for 14 days and each animal weighed around 40 g, the total dosage of
plant extract given to each mouse was 5.6 and 56 g, respectively. After the treatment period, MeHg exposure induced a significant deficit in the motor coordination, which was evident by a reduction (90%) in the falling latency in the rotarod apparatus. Interestingly, this phenomenon was completely recovered to control levels by CE co-administration, independent of dosages. MeHg exposure inhibited cerebellar
glutathione peroxidase (mean percentage inhibition of 42%) - an important
enzyme involved in the detoxification of endogenous
peroxides - and this effect was prevented by co-administration of CE. Conversely, MeHg exposure increased cerebellar
glutathione reductase activity (mean percentage inhibition of 70%), and this phenomenon was not affected by C. paludosa co-administration. Neither MeHg nor CE changed the cerebellar
glutathione levels. This study has shown for the first time, the in vivo protective effects of CE against MeHg-induced neurotoxicity. In addition, our findings encourage studies concerning the beneficial effects of C. paludosa on neurological conditions related to excitotoxicity and oxidative stress.