Abstract:
Herbal teas have been in used for many years globally for human wellbeing to manage stress without altering the physiological functions of the body. This research is aimed at investigating the neuroprotective and anti-stress effects of passion flower (Passifloraincarnata) tea and rooibos (Aspalathuslinearis) tea. The results of the phytochemical screening showed the presence of flavonoids, terpenoids, phlobatannins, alkaloids and saponins in both teas, with tannins only present in rooibos tea. The results revealed a higher phenolic content (total phenolic content, total flavonoid content) in rooibos hot water infusion compared with passion flower. The results also revealed that rooibos tea demonstrated significantly (P≤ 0.05) higher ferric reducing antioxidant power and radical scavenging capabilities (ABTS, DPPH, NO• and OH radical scavenging assays) than passion flower. The result of the neuroprotectiveactionin-vitro, revealed that rooibos tea had the highest acetylcholinesterase and butyrylcholinesterase inhibitory activity (62%, 50%)
The result of the behavioral testsrevealed that chronic stress elevates neurological, motor and cognitive impairment on day 1. Stressed + diazepam (DIA) group showed significant (p < 0.05) increase in the exploratory activities on day 14, with a decline on day 28. Oral administration of tested teas significantly (p < 0.05) increased exploratory activities; rat mobility, social interaction with other rats, time spent by rat in open, time spent by rat in brightly lit compartments, overall rearing and assisted rearing, and the number of transitions between compartments with peak action generally elicited on day 28 in a dose-dependent manner compared to the “stress treated” group.
The result of the liver function test showed that the “stressed untreated” group suffered significantly (p < 0.05) elevated levels of ALT, AST, ALP, urea and bilirubin compared with the rats in “control” group. However, post-treatment of the experimental rats with the tested teas was able to restore the impaired hepatic functions observed in “stressed untreated” rats in a dose-dependent manner. The post-treatment of stressed animals with passion flower and rooibos teas revealed increased activities of antioxidant enzymes (GSH, SOD and CAT) in the brain homogenate. Similarly, post-treatment with the studied tea infusions ameliorated the noticeable alterations of dopamine levels and acetylcholinesterase activity in treated rats. The result of this investigation showed that the tested teas most especially rooibos tea can be harnessed as functional beverage in the management of stress and other oxidative stress related diseases without any noticeable damaging effect on the liver.
