Neuropharmacological screening of Diospyros mespiliformis in mice B. Adzu a, *, S. Amos a , I. Muazzam b , U.S. Inyang a , K.S. Gamaniel a a Department of Pharmacology and Toxicology, National Institute for Pharmaceutical Research and Development (NIPRD), PMB 21, Abuja, Nigeria b Department of Medicinal Plant Research and Traditional Medicine, National Institute for Pharmaceutical Research and Development (NIPRD), PMB 21, Abuja, Nigeria Accepted 15 August 2002 Abstract The neuropharmacological activities of the aqueous extract of Diospyros mespiliformis stem bark were screened in mice. The extracts effect on pentobarbital-induced sleeping time, pentylenetetrazole induced seizure, spontaneous motor activity (SMA), exploratory behaviour, and rota-rod performance (motor coordination) were evaluated. The extract (100 and 200 mg/kg p.o.) produced a significant (P B/0.05) prolongation of pentobarbital-induced sleeping time, and reduced the SMA and exploratory behaviour. The extract prolonged onset of the phases of seizure activity but did not protect mice against lethality induced by pentylenetetrazole. It also failed to affect the motor coordination test. These results suggest that the extract contained an agent with neuropharmacological activity that may be sedative in nature. # 2002 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Diospyros mespiliformis ; Neuropharmacology; Mice 1. Introduction Diospyros mespiliformis Hochst (Ebenaceae) is a plant that grows wild in tropical Africa. The plant has white fragrant flowers and soft sweet fruit-pulp. The plant was reported to be of medicinal value. For instance; the leaves are used in sleeping sickness, malaria, headache and anthelmintic (Kerharo, 1974; Khan et al., 1980; Etkin, 1997) and the bark for cough (Nwude and Ebong, 1980; Arnold and Gulumian, 1984). The water and methanol extract of the leaf was reported to exhibit active antibacterial effects (Sanogo et al., 1998) while the chloroform and petroleum ether extract did not (Sawh- ney et al., 1978; Lajubutu et al., 1995; Adeniyi et al., 1990; Freiburghaus et al., 1996; Sanogo et al., 1998). Its stem bark was reported to contain alkaloids, quinones, saponins, sterol and/or triterpenes, and tannins (Dela- veau et al., 1979). The CNS activity of the plant has not been documented (NAPRALERT (SM) database). Accordingly, we evaluated the effect of the aqueous extract of the plant on pentobarbital-induced sleeping time, pentylenetetrazole-induced seizure, spontaneous motor activity (SMA), exploratory behaviour, and rota-rod performance (motor coordination) in mice. 2. Materials and methods 2.1. Plant material Mal. I. Muazzam of the Department of Medicinal Plant Research and Traditional Medicine, NIPRD, Abuja, collected the plant materials in Suleja, Niger State, Nigeria in November 2001. The identity of the plant was authenticated at the Taxonomy and a voucher specimen (number 5120) was deposited at the herbarium unit of the Institute. The dried material was powdered and 500 g were macerated in 2 l of cold distilled water for 24 h with occasional shaking, then filtered through Whatman number 1 filter paper and freeze-dried using Lyovac GT2 (Germany). This gave a yield of 8.67% w/w. * Corresponding author E-mail address: bulusadzu@yahoo.com (B. Adzu). Journal of Ethnopharmacology 83 (2002) 139  /143 www.elsevier.com/locate/jethpharm 0378-8741/02/$ - see front matter # 2002 Elsevier Science Ireland Ltd. All rights reserved. PII:S0378-8741(02)00249-0