SEDATIVE POTENTIAL OF SOME MEDICINAL PLANTS AND THEIR EFFECTS ON LIVER AND KIDNEY FUNCTIONS

Abstract

Over the years, the use of natural products as sedatives in the management of insomnia and associated disorders in folk medicine has gained a global significance. This needs arises because various synthetic drugs used in the management and treatment of insomnia have revealed serious side effects. The aim of this research work was to evaluate the phytochemical constituents, enzymic and non-enzymic antioxidant activities, and neuro-protective effects of ethanolic plants extracts (Cymbopogon citratus, Mangifera indica and Terminalia catappa). The study was also aimed at determining their sedative potential as well evaluating the effects of the plant extracts on liver and kidney function biomarkers. Phytochemical screening of the studied herb extracts revealed the presence of saponins, alkaloids, terpenoids and flavonoids in all the herbs, while anthraquinones, steroids, phlobatannins were absent in all the herbs, although tannins were present in Mangifera indica and Terminalia catappa but absent in Cymbopogon citratus. The studied herbs samples showed good antioxidant activities with Mangifera indica having the highest total phenolic content (TPC) and total flavonoid content TFC, (56.69 mg/g TAE and 73.10 mg/g QE respectively). Similarly, a higher reducing ability (5.55 mg/g AAE), DPPH radical scavenging activity (36910.26 %), ABTS radical scavenging activity (55305.56 μmol TE/g), Nitric oxide radical scavenging activity (84.64 %), and Hydroxyl radical scavenging activity (94.06 %) was recorded for Mangifera indica. The studied herbs reduced lipid peroxidation in a dose dependent manner with Mangifera indica having the highest inhibitory action in brain and in the liver. The result of the neuroprotective potential of the studied herbs revealed that Mangifera indica possessed the highest acetylcholinesterase inhibitory activity (74.57 %), butyrylcholinesterase inhibitory activity (86.91 %), and superoxide inhibitory activity (64.22 %). The effects of the studied plants using rats brain homogenate revealed that Mangifera indica have a higher potentiating effect on the levels of the evaluated antioxidant enzymes (glutathione: 3.28 mg/ml protein, glutathione peroxidise: 17.03 GSH consumed/min/mg protein, superoxide dismutase: 0.31 SOD U/mg protein, and catalase activity: 4.48 Catalase (Kat.f) and the least potentiating effect was recorded for Cymbopogon citratus (glutathione: 2.65 mg/ml protein, glutathione peroxidise: 10.82 GSH consumed/min/mg protein, superoxide dismutase: 0.04 SOD U/mg protein, and catalase activity: 3.01 Catalase (Kat.f). The result of the effect of the studied herbs on diazepam induced sleeping time at different concentration based on body weight revealed that all the studied herbs extended the sleeping time in the wistar rats with Mangifera indica (50 mg/kg body weight) recording the longest sleeping time (274.04±2.45 minutes). The result of the effect of the studied herbs on the assessed liver and kidney biochemical markers revealed that all the evaluated biochemical parameters at different concentrations of the herbs considerably fell within the reference range. Therefore, regular consumption of any of the herbs, most especially, Mangifera indica, can meet the nutritional requirement to manage and remedy insomnia at minimum with no damaging effect on the liver and the kidney.