Black tea: Phytochemicals, cancer chemoprevention, and clinical studies.

Tea (Camellia sinensis L.) is the most popular, flavored, functional, and therapeutic non-alcoholic drink consumed by two-thirds of the world's population. Black tea leaves are reported to contain thousands of bioactive constituents such as polyphenols, amino acids, volatile compounds, and alkaloids that exhibit a range of promising pharmacological properties. Due to strong antioxidant property, black tea inhibits the development of various cancers by regulating oxidative damage of biomolecules, endogenous antioxidants, and pathways of mutagen and transcription of antioxidant gene pool. Regular drinking of phytochemicals-rich black tea is linked to regulate several molecular targets, including COX-2, 5-LOX, AP-1, JNK, STAT, EGFR, AKT, Bcl2, NF-κB, Bcl-xL, caspases, p53, FOXO1, TNFα, PARP, and MAPK, which may be the basis of how dose of black tea prevents and cures cancer. In vitro and preclinical studies support the anti-cancer activity of black tea; however, its effect in human trails is uncertain, although more clinical experiments are needed at molecular levels to understand its anti-cancer property. This review discusses the current knowledge on phytochemistry, chemopreventive activity, and clinical applications of black tea to reveal its anti-cancer effect.

Integrating satellite images and spectroscopy to measuring green and black tea quality.

This study quantifies the effects of green leaf and black tea parameters that influence tea quality in Northeast India. It was motivated by a decline in tea quality that is of concern to tea growers. The rationale of the study is to identify the different parameters that have a significant influence on liquor brightness and other variables measuring tea quality. Here, we investigate several methods for estimating tea quality based on tea quality data, near infrared spectroscopy and remotely sensed data (NDVI). Attention focused on two high yielding clones (TV1 and S3A3). NDVI was obtained from ASTER images. Statistical analysis shows that liquor brightness is affected by the levels of caffeine content, theaflavins and catechins. Relationships exist between quality parameters and remote sensing in particular for the S3A3 clone. NDVI has a positive relation with caffeine, theogallin, EC, and ECG. NIR is negatively related to caffeine, theogallin, and catechins. We conclude that NDVI and Near Infrared (NIR) spectroscopy have a large potential to be used for monitoring tea quality in the future.