A review on the medicinal potential, toxicology, and phytochemistry of litchi fruit peel and seed

The perception that many fruit wastes, particularly the peel, contain more phytochemicals than the edible portions has been largely supported by scientific evidence, making them potential sources of bioactive and therapeutic phytochemicals. The peel and seed of Litchi (Litchi chinensis Sonn.) contain bioactive principles and have been shown to exhibit antioxidative, antidiabetic, cancer preventive, anti-obesogenic, and anti-inflammatory properties. This review presents a critical analysis of previous and current perspectives on the medicinal, toxicological, and phytochemical profiles of litchi fruit peel and seed, thus providing an evidence-based platform to explore their medicinal potential. A literature search was done on "PubMed," "Google Scholar," and "ScienceDirect." Peer-reviewed published data on the medicinal profiles of litchi fruit peel and seed were identified and critically analyzed. The fruit peel and seed improved glycemic control and insulin signaling and downregulated lipogenic and cholesterogenic processes. Their neuroprotective, hepatoprotective, and renal protective potentials were influenced by antioxidative and anti-inflammatory actions. The anticancer effect was mediated by upregulated proapoptotic, proinflammatory, antiproliferative, and anti-metastatic processes in cancer cells. Simple flavonols, sesquiterpenes, phenolic acids, jasmonates, and proathocyanidins are the possible bioactive principles influencing the medicinal effects. Appropriate toxicity studies are, however, still lacking. Litchi fruit wastes may be further studied as useful sources of therapeutic agents that may have medicinal relevance in oxidative, metabolic, vascular, and carcinogenic ailments. PRACTICAL APPLICATIONS: Underutilized fruit wastes contribute to environmental pollution. Interestingly, these wastes contain phytochemicals that could be of medicinal relevance if their medicinal potentials are maximized. Litchi fruit is a widely consumed fruit with commercial value. Its peel and seeds contribute to fruit wastes. The review exposes the medicinal potential and bioactive principles and/or nutrients of the fruit's peel and seed while elucidating the underlying therapeutic mechanisms or modes of actions through which litchi peel and seed potentiate medicinal effects. Thus, the review provides an evidence-based platform to explore the medicinal potential of underutilized wastes from litchi fruit. Additionally, the fruit peel and seed could be low-cost residues that could afford ecofriendly opportunity if their medicinal potentials are properly maximized.