Cognitive-enhancing, Anti-lipid Peroxidation, Qualitative Phytochemistry, and Toxic Effects of the Aqueous Aerial Part Extract of Launaea Cornuta (Hochst. Ex Oliv. And Hiern.)

Abstract

Currently, there is no cure for dementia and its associated complications like cognitive impairment, and the available medicines only offer symptomatic relief without altering the course of the disease. Conventionally utilised armamentaria for managing cognitive deficits suffer various drawbacks, such as low- efficacy, adverse effects, unaffordability, and inaccessibility which limit their clinical applications, hence the need for alternative therapies, especially from natural sources. Despite the longstanding ethnomedicinal usage of various plants to treat cognitive deficits, their pharmacological efficacy and safety have not been validated empirically. Therefore, this study was designed to investigate the acute oral toxicity, cognitive-enhancing, and anti-lipid peroxidation effects, and qualitative phytochemistry, of the aqueous aerial part extract of Launaea cornuta (Hochst. Ex Oliv. And Hiern.) based on its ethnomedicinal background. The acute oral toxicity effects of the aqueous aerial part extract of L. cornuta were investigated in Swiss albino mice using the up-and-down procedure described by the Organisation for Economic Cooperation and Development guideline number 425. The Morris Water Maze (MWM) technique was adopted to determine the cognitive-enhancing effects of the extract in Ketamine-induced cognitive-impaired mice. After that, the concentration of malondialdehyde (MDA) in the whole brain of experimental mice involved in the Morris Water Maze (MWM) experiment was determined using the Thiobarbituric Acid Reactive Substances (TBARS) method described previously. Qualitative phytochemical screening of the study extract was performed according to standard procedures. In this study, the aqueous aerial part extract of L. cornuta did not cause any clinical signs of acute oral toxicity in mice at all the tested doses and the median lethal concentration (LD50) was deemed to be >2000 mg/Kg bw, depicting its safety. The results further showed that the studied plant extract significantly (P<0.05) averted the Ketamine-induced cognitive impairment in mice dose-dependent, as witnessed by the reduced escape latencies and navigation distances and longer latencies in the target quadrant during the probe trial during the Morris Water Maze experiment. The extract significantly (P<0.05) reduced the malondialdehyde concentrations in mice in a dose-dependent fashion, inferring its anti-lipid peroxidation, hence antioxidative stress efficacy, partly explaining its ameliorative effects of ketamine-induced cognitive deficits in experimental mice. The results also revealed that the aqueous aerial part extract of L. cornuta contains various phytochemicals, such as flavonoids and phenols, associated with cognitive enhancement and antioxidant efficacy, among other pharmacologic effects. Therefore, this study concluded that the aqueous aerial part extract of L. conuta does not cause any observable clinical signs of acute oral toxicity in Swiss albino mice, possesses cognitive-enhancing and anti-lipid peroxidation effects, and contains various phytochemicals responsible for the reposted bioactivities, among other pharmacologic effects. Further empirical studies are recommended to determine and characterise the extract's specific cognitive-enhancing amalgams, specific action mechanisms, and complete toxicity profiles