Chemopreventive Agents
David E. Thurston, Ilona Pysz in Chemistry and Pharmacology of Anticancer Drugs, 2021
Allicin (Figure 12.34) is an organosulfur compound mainly found in garlic from the Amaryllidaceae family. Produced in garlic cells, when garlic is crushed, cut, or cooked, the enzyme alliinase converts alliin into allicin which produces the well-known aroma associated with fresh garlic. However, allicin is unstable and is converted into other sulfur-containing compounds such as diallyl disulphide. It has been suggested that this process is a defense mechanism against attack of garlic plants by insect pests. Structure of allicin.
Spices as Eco-friendly Microbicides: From Kitchen to Clinic
Mahendra Rai, Chistiane M. Feitosa in Eco-Friendly Biobased Products Used in Microbial Diseases, 2022
Allicin is a chemically oxygenated sulfur amino acid that occurs as a major component of garlic extract and has potent in vitro antimicrobial activity. Bacterial species like methicillin-resistant Staphylococcus aureus, Escherichia coli, Enterococcus, Shigella dysenteriae, S. flexneri, and S. sonnei are sensitive while Pseudomonas aeruginosa, Streptococcus β hemolyticus and Enterococcus faecium, are resistant to allicin (Ankri and Mirelman 1999). According to Yamada and Azuma (1977) pure allicin possess fungistatic and fungicidal activity against Candida, Cryptococcus, Trichophyton, Epidermophyton, and Microsporum at low concentration with MIC between 1.57 and 6.25 µg/mL. Allicin reacts with thiol compound (L-cysteine) to form the S-thiolation product, S-allylmercaptocysteine. However the main antimicrobial effect of allicin is due to its interaction with important thiol-containing enzymes. Allicin also specifically inhibits other bacterial enzymes such as the acetyl-CoA-forming system, consisting of acetate kinase and phosphotransacetyl-CoA synthetase. The wide spectrum antimicrobial effects of allicin are due to the multiple inhibitory effects they may have on various thiol-dependent enzymatic systems.
Herbal Products in Antihypertensive Therapy
Dilip Ghosh, Pulok K. Mukherjee in Natural Medicines, 2019
Garlic is consumed in different forms for its hypotensive effect: raw, aged, aqueous extract, oil, in powder form and in capsules (Banerjee et al. 2002; Frishman et al. 2009; Ried et al. 2013). Allicin (Figure 17.2) is considered the bioactive constituent of garlic, along with other sulphur-containing compounds. Allicin is found in freshly crushed gloves, but degrades into several allyl sulphides and polysulphides commonly termed garlic organosulphides (Figure 17.2). These organosulphides are also constituents of fresh garlic, but their concentrations increase in aged preparations (Schäfer and Kaschula 2014). Outcomes from meta-analysis studies suggest that aged garlic extract (AGE) produces a consistent lowering of blood pressure in comparison to other forms (Al Disi et al. 2016). Additionally, AGEs exhibit higher antioxidant potency than other types of garlic clove derivatives (Mathew and Biju 2008).
The beneficial effects of subcutaneous Allium cepa injection on random flap survival in rats
Published in Journal of Plastic Surgery and Hand Surgery, 2019
Dinçer Altınel, Merdan Serin, Havva Erdem, Burcu Biltekin, Mert Celikten, Sevgi Kurt Yazar, Gaye Toplu, Eymen Oruc
Anti-inflammatory effects of A. cepa have been shown in previous studies. Thiosulfinates have been related to these effects. Allicin is one of the well-known thiosulfinates which is an active ingredient of garlic. In onions, thiopropanal S-oxide, thiosulfonates, bis-sulfines, sulfides and cepaenes are the major sulfur-containing compounds instead of allicin. There are some studies showing that these sulfur compounds can inhibit cyclooxygenase (COX) and lipoxygenase activities [16,17]. These, as a result, could be responsible for the anti-inflammatory effects. Contrary to the previous studies in our study, we found that inflammatory findings were more prominent in the A. cepa group. Despite the increase in inflammation, vascular congestion scores were similar between the groups. In some of the earlier studies on flap survival, increased inflammation in the absence of infection has been associated with increased flap survival [18,19]. In addition, immunomodulatory effects of onion and garlic have been shown in previous studies. These effects have been related to an increase in IL2 and IL4 production which can alter T cell function [20]. These changes could alter the healing and inflammatory processes during flap recovery.
Inhibitory effect of Tunceli garlic (Allium tuncelianum) on blastocystis subtype 3 grown in vitro
Published in Expert Opinion on Orphan Drugs, 2020
Mehmet Aykur, Emrah Karakavuk, Muhammet Karakavuk, Mesut Akıl, Hüseyin Can, Mert Döşkaya, Yüksel Gürüz, Hande Dağcı
Garlic is one of the oldest medicines in the world used for medicinal purposes. It was shown by Pasteur to have an anti-bacterial effect, and then garlic was used in the treatment of gangrene during World Wars [58]. It has also been used as a medicinal plant for various biological activities, including anti-carcinogenic, antithrombotic, antimicrobial, anti-inflammatory, and antioxidant effects [59]. The medicinal effect of garlic is largely associated with the allicin, a sulfur compound. In addition, it contains many other complex components [60]. The antiparasitic effects of some components of garlic were investigated in Entamoeba histolytica, Giardia intestinalis, and trypanosomes [61,62]. In our study, it was found that A. tuncelianum extract had anti-Blastocystis effect against Blastocystis ST3 strain.
A mini review: garlic extract and vascular diseases
Published in Neurological Research, 2018
Yuequan Zhu, Raja Anand, Xiaokun Geng, Yuchuan Ding
Garlic (Allium sativum L.) has historical significance as a traditional medicine in many cultures. Its use was documented over 5000 years ago in Ayurvedic medicine, and over 3000 years ago in ancient Chinese medicine. Its use in treating heart disease was also documented in Africa over 3500 years ago in the ancient Egyptian Codex Ebers [4]. In modern times, garlic has demonstrated effectiveness in improving multiple cardiovascular health markers [5]. Epidemiologic studies have shown that garlic consumption reduces the progression of vascular disease. Unfortunately, the lack of standardization among garlic products has thus far limited the scalability of multi-study meta-analysis [6,7]. Different garlic products have various compounds, so the effects rely on its compositions [8,9]. The active ingredients of garlic include enzymes (e.g. alliinase), sulfur-containing compounds such as alliin, and compounds produced enzymatically from alliin (e.g. allicin). Allicin is the main bioactive component in the aqueous garlic extract and raw garlic products. Another important garlic preparation is aged garlic extract (AGE). AGE has a clear biological effect in the treatment of atherosclerosis and lowering the risk of cardiovascular diseases [10]. During the processing of AGE, the activity of S-allylcysteine (SAC) increased, which is an antioxidant and the key compound of AGE [8]. In this mini review, we summarize the key points regarding the mechanisms underlying garlic’s anti-hypertensive, anti-hyperlipidemic, and hypoglycemic effects.
Related Knowledge Centers
- Alliin
- Antifeedant
- Chirality
- Pyridoxal Phosphate
- Racemic Mixture
- Thioester
- Organosulfur Chemistry
- Alliinase
- Diallyl Disulfide
- Sulfenic Acid