Components identification and nutritional value exploration of tea (Camellia sinensis L.) flower extract: Evidence for functional food.

Camellia sinensis L., its fresh leaves and buds are used to make tea, is an important industrial crop with a long history. However, less attention has been paid to tea flowers. Indeed, tea flower extract (TFE) is a rich source of functional molecules, but its nutritional value remains unclear. This study, from the perspective of "whole food", aimed to investigate the composition of TFE and further explore its possible health-promoting effects on cyclophosphamide-induced mice. It was found that TFE was mainly composed of carbohydrates (34.02 ± 1.42%), phenolic compounds (11.57 ± 0.14%), crude proteins (27.72 ± 3.07%) and saponins (2.81 ± 0.00%). Supplementation of TFE at 200 mg/kg·BW/d regulated intestinal homeostasis by improving the intestinal barrier, alleviating dysbacteriosis (reverse 44 of 68 disordered genera), stimulated immunoreactions with significant enhancement of serum TNF-α, IFN-γ, IL-1β, IL-2 and IL-6. Furthermore, TFE could improve the liver function through decreasing the hepatic malondialdehyde and aminotransferase levels and increasing the levels of catalase, myeloperoxidase, superoxide dismutase and reduced glutathione. Notably, the ameliorating effects of TFE on cyclophosphamide-induced immunosuppression and the hepatic injury were associated with its modulation of gut microbiota. The results provide the evidence for the application of tea flower as potential functional food.