Hypnotic, anticonvulsant and anxiolytic effects of 1-nitro-2-phenylethane isolated from the essential oil of Dennettia tripetala in mice.
This study investigated the hypnotic, anti-convulsant and anxiolytic effects of 1-nitro-2-phenylethane (BPNE) obtained from the oil of Dennettia tripetala G. Baker (Annonaceae) and established its mechanism of action. The essential oil (EO) from the leaf, fruit and seed was obtained by hydrodistillation, followed by isolation of BPNE purified to 99.2% by accelerated gradient chromatography on silica, and identified by NMR and GC-MS. The pure BPNE and EO of the dried seed (93.6%) were comparatively evaluated for hypnotic, anticonvulsant and anxiolytic effects in mice. The acute toxicity of BPNE was determined and the LD50 was 490 mg/kg, intrapritonealy. The hypnotic activities of the EO and BPNE (50-400 mg/kg, i.p.) were assessed by loss of righting reflex, while sodium pentobarbitone (PBS) and diazepam (DZM) were used as positive controls. The anticonvulsant and anxiolytic effects of the EO and BPNE were evaluated in mice. Both BPNE and EO at doses ≥100 mg/kg induced spontaneous hypnosis with loss of righting reflex, significantly decreased sleep latency (SL) and also increased total sleeping time (TST) dose-dependently. They had comparable activity with NAP in TST. The BPNE exhibited higher hypnotic potency than EO at the same dose levels. The EO and BPNE offered comparable dose-related protections against PTZ- and strychnine-induced convulsions. Flumazenil (2 mg/kg) blocked the hypnotic and anticonvulsant (PTZ-convulsions) effects of both EO and BPNE. The essential oil at 5-20 mg/kg dose levels significantly (p<0.05) increased the percentage time spent and number of entries into the open arms. While at the same dose range BPNE significantly (p<0.05) increased the percentage time spent and the number of entries into the open arms respectively. The study concluded that 1-nitro-2-phenylethane exhibited dose dependent significant hypnotic, anticonvulsant and anxiolytic effects and it is the compound largely responsible for the neuropharmacological effects of the oil.
Department of Pharmacology, Obafemi Awolowo University, Ile-Ife, 220005 Osun State, Nigeria.
Idris Ajayi
IA
Oyemitan
Christianah Abimbola
CA
Elusiyan
Moses Atanda
MA
Akanmu
Tiwalade Adewale
TA
Olugbade
D000818:Animals; D029061:Annonaceae / Q000737:chemistry*; D014151:Anti-Anxiety Agents / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D000927:Anticonvulsants / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D001007:Anxiety / Q000188:drug therapy; D001362:Avoidance Learning; D001555:Benzene Derivatives / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005442:Flumazenil / Q000494:pharmacology; D018757:GABA Modulators / Q000494:pharmacology; D006993:Hypnotics and Sedatives / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D009822:Oils, Volatile / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use; D018514:Plant Structures; D057897:Reflex, Righting / Q000187:drug effects; D012640:Seizures / Q000139:chemically induced / Q000517:prevention & control; D012890:Sleep / Q000187:drug effects; D007319:Sleep Initiation and Maintenance Disorders / Q000188:drug therapy; D013331:Strychnine
C541822:1-nitro-2-phenylethane; D014151:Anti-Anxiety Agents; D000927:Anticonvulsants; D001555:Benzene Derivatives; D018757:GABA Modulators; D006993:Hypnotics and Sedatives; D009822:Oils, Volatile; D010936:Plant Extracts; D005442:Flumazenil; D013331:Strychnine
1-Nitro-2-phenylethane; 1-nitro-2-phenylethane; AGC; Annonaceae; Anticonvulsant; Anxiolytic; BPNE; CNS; DZM; Dennettia tripetala; EO; FMZ; GABA; Hypnosis; IOAA; LRR; NAP; PTZ; SL; TLC; TST; VEH; accelerated gradient chromatography; central nervous system; diazepam; essential oil; flumazenil; gamma amino butyric acid; index of open arm avoidance; loss of righting reflex; pentylene tetrazole; sleep latency; sodium pentobarbitone; thin layer chromatography; total sleeping time; vehicle