Short-term heating reduces the anti-inflammatory effects of fresh raw garlic extracts on the LPS-induced production of NO and pro-inflammatory cytokines by downregulating allicin activity in RAW 264.7 macrophages

• Published in: Food and chemical toxicology 2013-08, Vol.58, p.545-551
• Main Authors: Shin, Jung-Hye, Ryu, Ji Hyeon, Kang, Min Jung, Hwang, Cho Rong, Han, Jaehee, Kang, Dawon
• Format: Article
• Language: English
• Subjects: Allicin; Animals; anti-inflammatory activity; Biological and medical sciences; Cell Line; Cytokines; Cytokines - biosynthesis; Down-Regulation - drug effects; Garlic; Garlic - chemistry; heat; Heme oxygenase-1; Hot Temperature; Inflammation Mediators - metabolism; ingestion; interleukin-1beta; interleukin-6; Lipopolysaccharides - pharmacology; macrophages; Macrophages - drug effects; Macrophages - metabolism; Medical sciences; Mice; Nitric oxide; Nitric Oxide - biosynthesis; people; Plant Extracts - pharmacology; smell; Sulfinic Acids - metabolism; taste; Toxicology; tumor necrosis factor-alpha
• ISSN: 0278-6915; 1873-6351
• DOI: 10.1016/j.fct.2013.04.002

•Raw garlic extracts (RGEs) showed anti-inflammatory effects.•The anti-inflammatory effect was greater in fresh RGE (FRGE) than in heated RGE (HRGE).•The allicin concentration was higher in FRGE than in HRGE.•Allicin treatment reduced production of pro-inflammatory cytokines and nitric oxide.•Allicin treatment increased HO-1 activity. Garlic has a variety of biologic activities, including anti-inflammatory properties. Although garlic has several biologic activities, some people dislike eating fresh raw garlic because of its strong taste and smell. Therefore, garlic formulations involving heating procedures have been developed. In this study, we investigated whether short-term heating affects the anti-inflammatory properties of garlic. Fresh and heated raw garlic extracts (FRGE and HRGE) were prepared with incubation at 25°C and 95°C, respectively, for 2h. Treatment with FRGE and HRGE significantly reduced the LPS-induced increase in the pro-inflammatory cytokine concentration (TNF-α, IL-1β, and IL-6) and NO through HO-1 upregulation in RAW 264.7 macrophages. The anti-inflammatory effect was greater in FRGE than in HRGE. The allicin concentration was higher in FRGE than in HRGE. Allicin treatment showed reduced production of pro-inflammatory cytokines and NO and increased HO-1 activity. The results show that the decrease in LPS-induced NO and pro-inflammatory cytokines in RAW 264.7 macrophages through HO-1 induction was greater for FRGE compared with HRGE. Additionally, the results indicate that allicin is responsible for the anti-inflammatory effect of FRGE. Our results suggest a potential therapeutic use of allicin in the treatment of chronic inflammatory disease.