Tea is the most consumed beverage worldwide and has many health effects. Although there are many different types of tea, black tea and green tea comprise 98% of total tea production in the world. Tea waste production consists of withering, crushing, fermentation, drying and finally packaging processes. All of the waste generated during this production line is called tea waste. Tea production results in a significant amount of waste that cannot be effectively used for value creation. This waste contains many different components including protein, fiber, caffeine, and polyphenols. Due to its rich composition, it can be revalorized for different purposes. In this study, the general composition and bioactive compounds of tea waste were reviewed. Despite the fact that there have been few studies on the bioactivity of tea waste, those studies have also been discussed. The extraction techniques that are used to separate the compounds in the waste are also covered. It has been indicated that these valuable compounds, which can be separated from tea wastes by extraction methods, have the potential to be used for different purposes, such as biogas production, functional foods, food additives, silages, soluble packaging materials, and adsorbents. Although there are some studies on the revalorization of tea waste, new studies on the extraction of bioactive compounds are necessary to improve its utilization potential.

Along with the increased knowledge about the positive health effects of food bioactives, the eating habits of many individuals have changed to obtain higher nutritional benefits from foods. Fruits are among the most preferred food materials in this regard. In particular, berry fruits are important sources in the diet in terms of their high nutritional content including vitamins, minerals, and phenolic compounds. Berry fruits have remedial effects on several diseases and these health-promoting impacts are associated with their phenolic compounds which may vary depending on the type and variety of the fruit coupled with other factors including climate, agricultural conditions, etc. Most of the berries have outstanding beneficial roles in many body systems of humans such as gastrointestinal, cardiovascular, immune, and nervous systems. Furthermore, they are effective on some metabolic disorders and several types of cancer. In this review, the health-promoting effects of bioactive compounds in berry fruits are presented and the most recent in vivo, in vitro, and clinical studies are discussed from a food science and nutrition point of view.

Betulin is a bioactive compound found in large quantities in birch bark and has a triterpene pentacyclic structure. Through the oxidation of betulin, betulinic acid is obtained, which is found in large quantities in nature. Betulin and betulinic acid have multiple pharmacological properties such as antiviral, anti‐inflammatory, and anticancer properties. This comprehensive review aims to deepen the knowledge of the chemopreventive and chemotherapeutic effects of betulin and betulinic acid by presenting in vitro, in vivo, and clinical studies evaluating the anticancer mechanisms of betulin, betulinic acid, and their derivatives. The databases searched using specific MESh terms to conduct this review were PubMed/MEDLINE, Web of Science, TRIP database, Wiley, and Scopus. The anticancer properties of betulin and betulinic acid have been reported in a variety of experimental pharmacological studies using different types of cancer cell lines. It has been indicated that induction of apoptosis is the primary anticancer activity of these compounds by selectively affecting cancer cells. As shown by various research, the apoptotic cell death by these compounds is mainly related to factors such as type of cancer and cancer cell line, tumor size, source of betulin/betulinic acid, dose, treatment time, and the type of the drug delivery system employed. Numerous preclinical pharmacological studies and clinical trials on the chemopreventive and antitumour effects of betulin, betulinic acid, and their derivatives have been published. Future translational pharmacological studies establishing the exact anticancer dose effective in humans are needed.