BIOCHEMICAL EVALUATION OF TWO TEA INFUSIONS (HYPERICUM PERFORATUM AND MATRICARIA CHAMOMILLA) AS FUNCTIONAL FOODS IN MALE WISTAR RATS

Abstract

Herbal teas are beverages made from the infusion or decoction of herbs, spices, or other plant material in hot water, and usually do not contain caffeine. They are rich in polyphenols that are responsible for lowering the risk of developing several chronic degenerative diseases. This research was aimed at investigating the phenolic composition, antioxidant potential, minerals composition, antinutrients content, minerals bioavailability, the neuromodulatory activity and possible hepatotoxicity of the tea samples. Tannins, phlobatannins and steroids were common to both tea infusions with alkaloids, saponins, terpenoids and glycosides only present in H. perforatum while flavonoids were only found in M. chamomilla and mixed tea sample. HPLC-DAD identification of phenolic compounds revealed the presence of some flavonoids (catechin, quercetin, kaempferol, apigenin, rutin and luteolin) and phenolic acids [hydroxycinnamic acids (chlorogenic acid, caffeic acid and p-coumaric acid) and hydroxybenzoic acid (gallic acid)] in the tea samples. H. perforatum showed significantly higher total phenolic content (TPC) than M. chamomilla and the composite blend. Similar results were also obtained for total flavonoid content, reducing power, DPPH- and NO- radical scavenging activities, Lipid peroxidation (LPO) inhibitory activity in rat brain and superoxide inhibitory activity while the results of ABTS-+ and OH radical scavenging activities, LPO inhibitory activity in rat liver and anticholinesterase activity are different from the above observation where higher ABTS-+ scavenging activity was recorded in composite blend; higher OH radical scavenging activity and LPO inhibitory activity were recorded in M. chamomilla. Investigation on mineral composition of the samples revealed that potassium was the most abundant mineral and phosphorus the least abundant of all the evaluated minerals in all the samples while the contents of heavy metals like chromium, cadmium and nickel were below detection limit. The phytate, oxalate and alkaloids contents of the tea samples were significantly (p<0.05) low compared to the critical level in all three samples. Evaluated calcium and zinc bioavailability of the tea infusions showed that [Phytate]/[Calcium], [Oxalate]/[Calcium], [Phytate/Zinc] and [Calcium][Phytate]/[Zinc] were below the critical level of 0.5, 2.5, 15 and 200 respectively which are known to impair calcium and zinc bioavailability. The biochemical investigation results established that supplementation with H. perforatum, M. chamomilla and their composite mix tea infusions regulate and stabilize the serum concentrations of GGT, AST, ALT, ALP, T.PROT, LDH ALB, TBIL and glucose, thereby protect and maintain the functional integrity of hepatic cells. The results of the histological study of the liver sections from rats orally given tea infusion of H. perforatum, M. chamomilla and their composite mix tea infusions at doses 10, 30 and 50 mg/kg b.wt, showed normal structure with hexagonal lobules, central veins and peripheral triads embedded in connective tissue and this implies that these antioxidant-containing tea infusions do not have harmful effect on liver cells. It can therefore be concluded from this study that the infusions had no adverse effects on the liver histology and biomarkers at various tea concentrations administered to the rats. The presence of vital macro and micro minerals as well as those of phytochemicals in the tea samples makes them highly nutritious hence should be encouraged for use as functional foods. The result of this investigation also revealed that the studied tea samples could be explored in the management and prevention of Alzhemier's disease and stress- related diseases as well as free radical mediated diseases with further research.