Psychopharmacological evaluation of Croton sertanejus stems (a newly described segregated species of C. echioides, the northwestern muirapuama) in rodents

Abstract

Stems of Croton sertanejus Sodré & M.J.Silva - Euphorbiaceae, a species segregated from C. echioides Baill (northeastern muirapuama), have been marketed in Brazil as a substitute for the Amazonian muirapuama Ptychopetalum olacoides Benth. - Olacaceae, recommended for central nervous system disorders. This study aimed to verify the similarity of central pharmacological effects that could justify the interchangeability between them. To this end, potential anxiolytic, antidepressant, antinociceptive effects, and effects on memory were evaluated using a lyophilized extract of C. sertanejus stems in rodents subjected to various experimental models, as well as an assessment of cholinesterase activity. A reduction in spontaneous movement and significance in three parameters from the elevated plus-maze and light-dark box tests were observed, indicating an interesting anxiolytic activity that should be explored in future studies. The formalin test did not show antinociceptive effects but suggested a potential hyperalgesia at a dose of 100 mg/Kg. The cholinesterase activity of the extract was positive in in vitro test, and spectrophotometric evaluation of this activity indicated an inhibitory concentration (IC50) of 2.87 mg/mL. No other significant effects were observed, indicating an absence of antidepressant, antinociceptive, or memoryreversing effects of scopolamine-induced amnesia. Since P. olacoides shows anxiogenic effects, antidepressant activity, anticholinesterase activity, and improvement in the memory of animals, it can be concluded that the stems of C. sertanejus, besides botanical and phytochemical differences, exhibit a pharmacological profile distinct from that of the Amazonian muirapuama, with similarity only in the positive anticholinesterase activity. This confirms that it is not a substitute drug, but indeed an adulterant.