Antioxidant Capacities and Phytoconstituents of Fractions of Ethanol Extract of Cymbopogon citratus (DC.) Stapf: Inhibition of Iron II (Fe2+) - Induced Lipid Peroxidation in Rat Colon Homogenate

Oxidative stress is associated with the generation of excess free radicals and reduction in the levels of antioxidant enzymes. It is also implicated in the initiation and progression of colorectal cancer. Cymbopogon citratus, commonly called ‘lemon grass,’ is widely distributed in the tropics and it is known for its therapeutic applications. In this study, the antioxidant activities of the crude ethanol extract of Cymbopogon citratus and its fractions were determined using total antioxidant capacity (TAC), 2-2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, Fe3+ reducing ability, total phenolic content (TPC) and total flavonoid content (TFC). The phytocomponents were determined through Gas Chromatography - Mass Spectrometry and lipid peroxidation was induced in rat colon homogenate. TFC and TPC were highest in the ethyl acetate fraction (EAF) > crude extract (CE) > ethanol fraction (EF) > chloroform fraction (CF). Both DPPH scavenging activity and Fe3+ reducing ability exhibited similar trend; EAF > EF > CF > CE. In addition, the ability to inhibit lipid peroxidation in rat colon is as follows; EAF> CF > CE > EF. The EAF and CF of the ethanol extract of C. citratus contain most of the compounds that could be responsible for its activity against reactive oxygen species

Melatonin and Vitamin C modulate cholinergic neurotransmission and oxidative stress in scopolamine-induced rat model of memory impairment

Background: Cognitive dysfunction which characterizes dementia is reportedly caused by multiple factors including oxidant-antioxidant imbalance, inflammation, alteration in synaptic neurotransmission. Despite the arrays of drugs available in managing dementia, it appears no single drug can effectively treat dementia. Since it is multifactorial, combining potential drugs may provide neuroprotective impact. As such, this study investigated the neuroprotective effects of melatonin and vitamin C on scopolamine model of cognitive impairment in rats and the possible mechanism of action. Methods: Thirty male Wistar rats were divided to receive either normal saline (5 ml/kg, p.o), scopolamine (1 mg/kg, i.p.), donepezil (2 mg/kg, p.o), melatonin (10 mg/kg, p.o), vitamin C (100 mg/kg. p.o) or melatonin plus vitamin C. Cognitive impairment was induced by daily injection of scopolamine (1 mg/kg, i.p.), after which different treatment regimen were administered for 15 days. Spatial memory was assessed using Morris Water Maze and modified light and dark box. The brain was processed for malondialdehyde (MDA), reduced glutathione (GSH) and acetylcholinesterase (AchE) activity. Results: Scopolamine-treated rats with no intervention showed impaired learning and memory as depicted by a significant (p<0.05) increase in escape latency, reduction in the frequency of visit to the escape aperture, increased MDA, decreased GSH and elevated acetylcholinesterase activity when compared to other groups. Interventions with melatonin or/and vitamin C reversed these responses respectively. The melatonin plus vitamin C treated group compared favorably with donepezil (reference group). Conclusion: Melatonin and vitamin C show neuroprotective effect in attenuating cognitive impairment in scopolamine-induced model by modulating oxidative stress pathway and enhancing cholinergic neurotransmission. Keywords: Dementia, Melatonin, Vitamin C, Memory, Scopolamine

Seed germination and emergence of Setaria pallidefusca and Pennisetum pedicellatum (Cyperales: Poaceae) in Nigeria

Seed weight, viability, gennination and emergence of Setaria pallidefusca and Pennisetum pedicellatum were determined under controlled conditions. The seeds of S . pallidefusca and P. pedicellatum had 97% and 94% víability respectively. Optimum gennination ofall seeds occurred at 25°C. Maximum seedling emergence occurred at the soil surface, there was a progressive decrease at greater depth. Maximum depth for emergence were 5 cm (S . pallidefusca) and 7 cm (P. pedicellatum). Seeds of both species germinated well under varied light conditions. However, there was less gennination under continuous light or darlmess conditions than under altemating day and night conditionsEn condiciones de laboratorio, se determinaron el peso, la viabilidad, la germinación y la "emergencia" en semillas de Setaria pallidefusca y Pennisetum pedicellatum. Respectivamente, la viabilidad fue de 97 y 94%. La germinación óptima se dio a los 25 OC y la máxima emergencia en la superficie del suelo, con una disminución progesiva a mayor profundidad. La profundidad máxima emergencia fue 5 cm (S. pallidefusca) y 7 cm (P. pedicellatum). Las semillas de ambas especies germinaron bien en varias condiciones de iluminación. Sin embargo, hubo menos germinación con luz y oscuridad continuas, que cuando se alternaban luz y oscurida

Seed germination and emergence of Setaria pallidefusca and Pennisetum pedicellatum (Cyperales: Poaceae) in Nigeria

Seed weight, viability, gennination and emergence of Setaria pallidefusca and Pennisetum pedicellatum were determined under controlled conditions. The seeds of S . pallidefusca and P. pedicellatum had 97% and 94% víability respectively. Optimum gennination ofall seeds occurred at 25°C. Maximum seedling emergence occurred at the soil surface, there was a progressive decrease at greater depth. Maximum depth for emergence were 5 cm (S . pallidefusca) and 7 cm (P. pedicellatum). Seeds of both species germinated well under varied light conditions. However, there was less gennination under continuous light or darlmess conditions than under altemating day and night conditionsEn condiciones de laboratorio, se determinaron el peso, la viabilidad, la germinación y la "emergencia" en semillas de Setaria pallidefusca y Pennisetum pedicellatum. Respectivamente, la viabilidad fue de 97 y 94%. La germinación óptima se dio a los 25 OC y la máxima emergencia en la superficie del suelo, con una disminución progesiva a mayor profundidad. La profundidad máxima emergencia fue 5 cm (S. pallidefusca) y 7 cm (P. pedicellatum). Las semillas de ambas especies germinaron bien en varias condiciones de iluminación. Sin embargo, hubo menos germinación con luz y oscuridad continuas, que cuando se alternaban luz y oscurida

Rapid eye movement sleep deprivation impairs hippocampus-dependent spatial memory: involvement of GABAergic receptors

Background: This study examined the effect of rapid eye movement (REM) sleep deprivation on spatial memory in Wistar rats and the role of GABAergic receptors.Methods: A total of thirty-six age matched male Wistar rats weighing 170-200g were grouped into six (A-F) of six animals each. Group A served as control, Group B was sleep deprived, rats in groups C-F in addition to being sleep deprived for 72 hrs, received Diazepam (1mg/kg) (C), Baclofen (5mg/kg) (D), Phaclofen (1mg/kg) (E), Bicuculline (2mg/kg) (F) respectively. Spatial memory was accessed using Morris water maize (MWM) while motor performance (MP) and working memory were accessed using Y-Maze. Some serum biochemical parameters were also assessed.Results: These showed that spatial memory was decreased in the sleep deprived group compared with control (p<0.05). Diazepam increased, while Bicuculline decreased time latency in the MWM compared with sleep-deprived group (p<0.05). MP in the Y maze was significantly reduced (p<0.05) in all groups compared with control. Serum Creatine kinase (CK) and calcium as well as hippocampal CK were significantly (p<0.05) increased in the sleep-deprived group compared with control.Conclusion: REM sleep deprivation produced impairment in spatial memory in rats which is at least in part mediated by Gabaergic mechanisms with GABA A receptors being more implicated than the B subtype.Keywords: Rapid eye movement sleep, sleep deprivation, spatial memory, GABA receptor