Genus Melaleuca - A Review on the Phytochemistry and Pharmacological Activities of the Non-Volatile Components

Plants of the genus Melaleuca which belong to family Myrtaceae, commonly named "tea trees”, are economically important plants. When talking about tea trees, the essential oils are the center of attention, leaving all other phytoconstituents in their shade. Many reviews addressed the composition and pharmacological activities of Melaleuca alternifolia L. essential oil as the most common one. To date, there are no detailed reviews summarizing the phytochemical and pharmacological properties of the non-volatile components of members of the genus Melaleuca. After distillation of the volatile oil, large amounts of these plants’ waste remain untapped. This review indicates that this genus is a rich source of diverse groups of bioactive phytochemicals, including flavonoids, triterpenoids, benzylic phloroglucinol-terpene derivatives, polyphenols, hydrolysable tannins, and other compounds. It also discusses the diverse pharmacological activities reported for plants of this genus.