Preliminary Studies on the Behavioural Effects of the Methanol Extract of Leonotis Nepetifolia Linn Stem in Mice

Abstract

Background: Leonotis nepetifolia Linn (Lamiaceae) is used in traditional medicine for its calming (tranquilizing) effects. The aim of this study was to determine whether there is any scientific justification for this use. To achieve this purpose, we investigated the behavioural effects of the methanol extract of Leonotis nepetifolia stem (37.5, 75 and 150 mg/kg) in mice. Methods: Acute toxicity studies were carried out on the methanol stem extract of Leonotis nepetifolia to determine the LD50. The behavioural tests employed were diazepam-induced sleep onset and duration, hole board assay for exploratory activity, mouse beam walk assay for motor coordination, and the staircase test for the detection of anxiolytic compounds. Preliminary phytochemical screening was also carried out on the extract. Results: The intraperitoneal LD50 value was found to be 3.8 g/kg. The results showed that the extract significantly prolonged the duration of diazepam-induced sleep at the highest dose (150 mg/kg). There was no observable effect on exploratory activity and motor coordination at the doses tested (37.5, 75 and 150 mg/kg). The extract, however, at 150 mg/kg elicited a significant decrease in the number of rearings in the staircase test, an effect also observed in the group of mice injected with an anxiolytic dose of diazepam. The preliminary phytochemical screening revealed the presence of alkaloids, saponins, glycosides and triterpenoids. Conclusion:The results obtained suggest that the crude methanol extract of Leonotis nepetifolia stem possesses some biologically active constituents with potential anxiolytic activity and thus may justify its traditional use as a tranquilizer.

Medicinal plants with reported anxiolytic and sedative activities in Nigeria: A systematic review

“…This is shown in from this analogy. As such, low anxiolytic activity was seen at a lower dose and high anxiolytic activity at a higher dose by Albizia glaberrima (Adebesin et al, 2015), Alchornea cordifolia (Akanmu et al, 2011), Alternanthera brasiliana (Oyemitan et al, 2015a), Artocarpus altitis (Onasanwo et al, 2017), Asystesia gangetica (Adeyemi et al, 2014), Cissus cornifolia (Yaro et al, 2015b), Hippocratea africana (Okokon et al, 2014), Leonotis nepetifolia (Ayanwuyi et al, 2016), Maerua angolensis (Malami et al, 2014b), Ocimum gratissimum (Okoli et al, 2010b), Parkia biglobosa (Tijjani et al, 2014), Piliostigma thonningii (Adamu et al, 2013), and Senna occidentalis (Cleatus et al, 2017). Similarly, high sedative property was seen at a lower dose with low sedative property at a higher dose by Hedranthera barteri (Onasanwo et al, 2010) and Musa sapientum (Salako et al, 2018).…”