Abstract
Aqueous (A), hydroalcoholic (AE) and ethanolic (E) extracts and fractions of dried calyxes of Hibiscus sabdariffa were evaluated for anxiolytic property using elevated-plus maze (EPM), and sedative
properties using ketamine-induced sleep in animal models. The extracts exhibited a dose-dependent increase in the time spent in the open arm with ethanol extracts having the best anxiolytic activity. The extracts at A5mg/kg, AE5mg/kg and A50mg/kg did not cause an increase in time spent in the open arms (p<0.05) but other doses significantly did when compared with the vehicle control. The fractions of the hydroalcoholic extracts showed no significant anxiolytic activity. Neither the extracts nor the fractions significantly reduced or increased latency to sleep after a single dose except AE300 (p<0.01). There was significant reduction in onset of sleep, and increase in sleeping time with A and AE extracts with multiple doses at A300, AE50 and AE300mg/kg dose groups (p<0.001, p<0.01 and p<0.05 respectively). A reduction in sleeping time after several daily doses of ethanol extracts doses was observed. A single dose of one of the fractions (EAC at 50mg/kg) caused a significant reduction (p<0.05) in sleep duration. The study showed that extracts of Hibiscus sabdariffa possess anxiolytic and sedative effects which become more pronounced with administration of repeated doses of the extracts.
Keywords: Anxiolytic, sedative, Hibiscus sabdariffa extracts
Résumé
Les extraits aqueuse (A), hydroalcoliques (AE) et éthanoïque (E) et les fractions des calyxes sèches d’Hibiscus sabdariffa étaient évalués pour leur propriétés anxiolytiques utilisant le maiis plus élevé (EPM), et les propriétés sédatives utilisant la ketamine-induisant le sommeil aux animaux. Les extraits démontraient une dose dépendent croissante de temps mis dans les groupe ouvert avec les extraits méthanoïques ayant la meilleure activité anxiolytique. Les extraits a la dose de A5mg/kg, AE5mg/kg et A50mg/kg ne causaient pas d’augmentation da temps mis dans ce groupe (p<0.05) mais d’autres doses augmentaient significativement lorsque comparé le groupe de contrôle. Les fractions des extraits hydroalcoliques ne démontraient d’activité anxiolytique significative. Ni les extraits, ni les fractions ne réduisaient ou n’augmentaient significativement le temps du sommeil après un dose unique à l’exception du AE300 (p<0.01). Il y avait une réduction significative du début du sommeil et augmentait le temps du sommeil avec les extraits A et AE à des doses multiples de A300, AE50 et AE300mg/kg dosage par groupe (p<0.001, p<0.01 et p<0.05 respectivement). La réduction de temps de sommeil après plusieurs doses journalières d’extraits du méthanol était observée. Une dose unique de la fraction (EAC de 50mg/kg) causait une réduction significative de la durée du sommeil (p<0.05). Cette étude démontrait que les extraits d’Hibiscus sabdariffa possèdent des effets anxiolytiques et sédatifs qui deviennent plus intense avec l’administration des doses répétées des extraits.
Correspondence: Dr. Titilayo O. Fakeye, Department of Clinical Pharmacy and Pharmacy Administration, University of Ibadan, Ibadan Nigeria. Email: titifakeye@yahoo.com
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