A review on coffee leaves: Phytochemicals, bioactivities and applications

Coffee leaves have a long history for use as ethnomedicine and tea beverage by locals from countries where coffee plants grow. Recently, attentions have been paid to their health benefits to human beings because of abundant bioactive components in coffee leaves. However, the researches related to the bioactivities, applications, and the impacts of processing methods on the phytochemical composition and activities of coffee leaves are scarce. The reviews specific to coffee leaves in these aspects are rare too. Due to the growing interests to coffee leaves, in this review, the chemical compositions in coffee leaves and the influence of environmental conditions and processing methods on them were summarized. Furthermore, various applications of coffee leaves, including ethnomedicine, coffee leaf tea, therapeutic agent, packaging material, tobacco substitute, organic fungicide, personal hygienic products, and animal feed et al. were presented. The future prospects of coffee leaves are also discussed. In conclusion, coffee leaf is a very promising resource in the areas of food and industry, especially, in the beverage industry. The researches in understanding impacts of the processing methods on the phytochemicals, enzymes, bioactivities, and flavor of coffee leaves are highly needed.