Alliumin

Natural resources such as plants are an upright curing option in treating cancers and reducing the side effects of current therapeutic modalities. Allium genus vegetables are of the most interesting herbs in restricting cancers that includes garlic, onions, leeks, chives, and shallots. These plants have been exploited in folk medicine because of their beneficial health effects in improving numerous diseases. The phytochemical analysis of various Allium genus members showed that, to date, 16 species have proved potential anticancer properties due to the accumulation of various sulfur and organic compounds like S-allyl mercaptocysteine, quercetin, flavonoids, and ajoene. These compounds with various mechanisms such as hindering cell cycle, inhibiting signaling pathways, inducing apoptosis, and antioxidant activity interfere with diverse stages of formation, growth, differentiation, and metastasis of cancer cells. Similar to garlic and onion, other species have exhibited anticancer activities, so that active natural molecules extracted from them might serve as possible anticancer agents. Therefore, evaluating the main ingredients and studying their anticancer mechanisms are of great importance. In this review, we aim to summarize the available data on anticancer mechanisms of 16 species of Allium genus and their major compounds to assist further researches on the treatment and prevention of cancers.

Allium species, belonging to Alliaceae family, are among the oldest cultivated vegetables used as food. Garlic, onions, leeks and chives, which belong to this family, have been reported to have medicinal properties. The Allium species constituents have been shown to have antibacterial and antioxidant activities, and, in addition, other biological properties. These activities are related to their rich organosulfur compounds. These organosulfur compounds are believed to prevent the development of cancer, cardiovascular, neurological, diabetes, liver diseases as well as allergy and arthritis. There have also been reports on toxicities of these compounds. The major active compounds of Allium species includes, diallyl disulfide, diallyl trisulfide, diallyl sulfide, dipropyl disulfide, dipropyl trisulfide, 1-propenylpropyl disulfide, allyl methyl disulfide and dimethyl disulfide. The aim of this review is to focus on a variety of experimental and clinical reports on the effectiveness, toxicities and possible mechanisms of actions of the active compounds of garlic, onions, leek and chives.

The Allium genus includes garlic, onions, shallots, leeks, and chives. These vegetables are popular in cuisines worldwide and are valued for their potential medicinal properties. Epidemiologic studies, while limited in their abilities to assess Allium consumption, indicate some associations of Allium vegetable consumption with decreased risk of cancer, particularly cancers of the gastrointestinal tract. Limited intervention studies have been conducted to support these associations. The majority of supportive evidence on Allium vegetables cancer-preventive effects comes from mechanistic studies. These studies highlight potential mechanisms of individual sulfur-containing compounds and of various preparations and extracts of these vegetables, including decreased bioactivation of carcinogens, antimicrobial activities, and redox modification. Allium vegetables and their components have effects at each stage of carcinogenesis and affect many biologic processes that modify cancer risk. This review discusses the cancer-preventive effects of Allium vegetables, particularly garlic and onions, and their bioactive sulfur compounds and highlights research gaps.