The majority of the by products formed during onion processing remain unutilized, yet they are rich in bioactive compounds and phytochemicals. Onions are a very valuable vegetable. Onion chemical compounds are incredibly diverse, and they work through a variety of pharmacological mechanisms to prevent disease. Although the mechanism of the action of the chemicals found in onions has been studied, there is still room for further reformulating of nutrient supplements and pharmaceutical treatments thanks to a growing interest in sustainable resource utilisation and circular economy. This review focuses on the primary bioactive components found in onion peel and skin, particularly total phenolics, quercetin, total flavonoids, and their derivatives, as well as their therapeutic uses such as cardioprotective, anticancer, neuroprotective, antiobesity, antidiabetic, and antibacterial constituents. This review article noted that onion peel is a valuable agricultural byproduct that has a variety of biologically active compounds so it can be used as a health-regulating ingredient, particularly in the biomedical and pharmacological domains.

Cancer is one of the leading diseases, causing deaths worldwide. Nearly 10 million deaths were reported in 2020 due to cancer alone. Several factors are involved in cancer progressions, such as lifestyle and genetic characteristics. According to a recent report, extracellular vesicles (EVs) are involved in cancer initiation, progression, and therapy failure. EVs can play a major role in intracellular communication, the maintenance of tissue homeostasis, and pathogenesis in several types of diseases. In a healthy person, EVs carry different cargoes, such as miRNA, lncRNA etc., to help other body functions. On the other hand, the same EV in a tumor microenvironment carries cargoes such as miRNA, lncRNA, etc., to initiate or help cancer progression at various stages. These stages may include the proliferation of cells and escape from apoptosis, angiogenesis, cell invasion, and metastasis, reprogramming energy metabolism, evasion of the immune response, and transfer of mutations. Tumor-derived EVs manipulate by altering normal functions of the body and affect the epigenetics of normal cells by limiting the genetic makeup through transferring mutations, histone modifications, etc. Tumor-derived EVs also pose therapy resistance through transferring drug efflux pumps and posing multiple drug resistances. Such EVs can also help as biomarkers for different cancer types and stages, which ultimately help with cancer diagnosis at early stages. In this review, we will shed light on EVs’ role in performing normal functions of the body and their position in different hallmarks of cancer, in altering the genetics of a normal cell in a tumor microenvironment, and their role in therapy resistance, as well as the importance of EVs as diagnostic tools.