Honey is a natural sweet substance that bees produce by transforming flower nectar or other sweet secretions of plants. It has widespread use in traditional medicine in various parts of the world. It has been reported to assist in building the entire central nervous system. The beneficial effects of honey have been attributed to the possible polyphenolic contents and some other constituents. The geographical locations and the sources of plant nectars may contribute to the effects of honey samples. Thus, we evaluated the neuropharmacological effects of six samples of honey (10%, 20% and 40% V /v, p.o.) from three geographical locations of Nigeria using the following behavioral models: Novelty-induced behaviors (NIB), learning and memory, pentobarbital-induced hypnosis, anxiolytic, anticonvulsant, analgesic and antidepressant models in mice. The results showed that honey significantly (p< 0.05) decreased locomotion and rearing behaviors in NIB and amphetamine-induced locomotor activity when compared to the control group. Exploratory behavior was significantly increased in both holeboard and elevated plus maze but had no significant effect on spatial working memory. Honey sample from Umudike has significant hypnotic and anticonvulsant effects. The antinociceptive models (hot plate and tail flick tests) showed that the honey samples significantly increased the pain reaction time and naloxone blocked these central antinociceptive effects. The force swimming test showed that only the Idanre (ID) honey sample had antidepressant effect. In conclusion, some of these honey samples have central inhibitory property, anxiolytic, antinociceptive, anticonvulsant and antidepressant effects, thus may be used as nutraceutic. It can also be inferred that some of these effects are probably mediated through dopaminergic and opioidergic systems.

Background: Combretum micranthum G. Don. (Combretaceae) is an ethnomedicinally valuable, undomesticated and indigenous shrub of West Africa. However, its anxiolytic potential have not been reported despite its ethanolic extract being used ethnomedicinally in the management of anxiety disorders.Aim: To determine the acute toxicity effect and assess the behavioural effects and anxiolytic potential of C. micranthum G. Don. leaves in mice.Settings: This study is an experimental design to evaluate the ethnomedicinal claim of Combretum micranthum G. Don using animal models of anxiety.Methods: Fifty-six male and female mice, ranging in weight between 20 g and 30 g were randomly distributed into three main groups. The first group of mice (n = 6) was assigned for toxicity assessment (LD 50 ) study using the guideline of Organization for Economic Cooperation and Development (OECD). The second group of mice for behavioural study (n = 25) was further divided into five sub-groups. Sub-groups I, II and III were orally administered 500 mg/kg, 1000 mg/kg, 2000 mg/kg of ethanolic extract of C. micranthum (CmEE), respectively, whilst IV and V were intraperitoneally administered 1 mg/kg diazepam and normal saline 0.5 mL, respectively. They were thereafter evaluated for novelty-induced behaviours: locomotion, rearing and grooming using Open Field Test (OFT). The third group of mice (n = 25) was treated similar to the pattern used in behavioural study and evaluated for anxiolytic activity of CmEE using elevated plus maze (EPM) model. Data were expressed as mean ± standard error of mean (S.E.M) and analysed using Student's-t test, and one-way analysis of variance (ANOVA) followed by Student-Newman-Keuls (SNK) test with values of p < 0.05 considered significant. Results:The percentage yield of ethanolic leaf extract of C. micranthum was 14.28% weight/ weight (w/w). Combretum micranthum showed no toxicity when administered orally to mice (LD 50 ≥ 2000 mg/kg). Groups administered 500, 1000 and 2000 mg/kg of CmEE exhibited decreased locomotion (p < 0.05) when compared with saline group. There was significant decrease in rearing at 2000 mg/kg but increase in grooming in mice administered 2000 mg/kg of CmEE was recorded. The groups administered 500, 1000 and 2000 mg/kg of CmEE showed increased percentage time spent in the open arm in a dose-dependent pattern (33.3%, 41.6% and 55.4%, respectively) when compared with the saline group. There were significant dosedependent decreases in the indices of open arm avoidance at 1000 (48.9) and 2000 mg/kg (41.4) of CmEE. Conclusion:Combretum micranthum is non-toxic and preliminary data indicated that it possesses anxiolytic potential. However, it is recommended that further assays using other specific models of anxiety to determine its probable mechanism(s) of action should be explored.

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Plant extracts as potential phytotherapeutic products are supposed to be safe. However, adverse and untoward fatal effects have been reported. Study aimed to evaluate the safety and toxicity of aqueous extracts of Camellia sinensis, Parquetina nigrescens and Telfairia occidentalis leaves. The extracts were subjected to brine shrimp lethality bioassay and toxicities by Lorke's method. Mice were given oral leaves extracts of C. sinensis (1000, 2000, 4000 mg/kg and 700, 1400, 2800 mg/kg); P. nigrescens (3000, 6000, 12000 mg/kg and 2000, 4000, 8000 mg/kg) and T. occidentalis (2500, 5000, 10,000 mg/kg and 1750, 3500, 7000 mg/kg) for acute and Sub-acute toxicity studies respectively. Toxicity was observed for the first 4hrs, then over a period of 24hrs and at least once daily for 14 days extended to 28 days. General behavior, adverse effects and mortality observed and evaluated throughout the experimental period. Camellia sinensis (LC50=418.6 µg/mL) with least toxicity on the brine shrimps compared to P. nigrescens (LC50=32.34 µg/mL) and T. occidentalis (LC50=8.32 µg/mL). LD50 of the extracts; 2800, 8000 and 7000 mg/kg for C. sinensis, P. nigrescens and T. occidentalis respectively. No death, No changes in body and relative organ weights. However, C. sinensis and T. occidentalis significantly increased in Haemoglobin (C. sinensis: 15.90 ± 0.33 (p < 0.00) and T. occidentalis: 14.67 ± 0.22 (p < 0.01)), PCV (C. sinensis: 46.20 ± 1.02 and T. occidentalis: 44.00 ± 0.71 (p < 0.00)), RBC (C. sinensis: 5.55 ± 0.12 and T. occidentalis: 5.49 ± 0.12 (p < 0.00)). No histomorphological changes in the vital organs except P. nigrescens with mild kidney interstitial fibrosis, mild glomerular hypercellularity and mild liver microhemorrhages. Various doses of the extracts did not cause mortality or serious signs of toxicity in mice.