Ginger as a powerful Antioxidant
Ginger is rich in antioxidants. The antioxidants play a vital role in neutralisation of free radicals. The antioxidative defense system of the body balances the free radicle production. Oxidative stress occurs in the event of alterations between reactive oxygen species generation and its neutralisation by the antioxidant defense. Moreover, ginger plays an essential role in the reduction of the lipid oxidation and inhibits the pathogenesis of diseases. 6-Dehydroshogaol, 6-shogaol and 1-dehydro-6-gingerdione are inhibitors of nitric oxide synthesis in activated macrophages. 6-shogaol has potent antioxidant properties due to the presence of unsaturated ketone moiety.
Inflammation is a complex immune process, involving various mediators such as interleukin-1, tumour necrosis factor and anti-inflammatory cytokines. Ginger oil significantly represses inflammation, especially joint swelling. Also, ginger extracts suppress the synthesis of pro-inflammatory cytokines and play a significant role in the inhibition of cyclooxygenase and 5-lipoxygenase, essential for arachidonate metabolism, and down-regulating the induction of inflammatory genes.
Ginger extracts suppress tumour development through up-regulation of tumour suppressor gene, induction of apoptosis and inactivation of vascular endothelial growth factor pathways. The development and progression of tumours involve multiple steps including genetic and metabolic changes. 6-gingerol suppresses the transformation, hyperproliferation, and inflammatory processes that involve in various phases of carcinogenesis, angiogenesis, and metastasis. Besides, ginger constituents induce apoptosis in prostate cancer cell line LnCaP by increasing the expression of tumour suppressor p53 and Bax and also decreasing the expression of Bcl-2. 6-shogaol is effective against breast cancer through the inhibition of cell invasion and reduction of matrix metalloproteinase-9 expression. On the other hand, 6-gingerol stimulates apoptosis through up-regulation of NAG-1 and G1 cell cycle arrest through down-regulation of cyclin D1.
Ginger root extracts and gingerol inhibit the growth of Helicobacter pylori CagA+ strains, which has a specific gene, linked to the development of gastric premalignant and malignant lesions. 6-shogaol induces apoptosis in human colorectal carcinoma cells via the production of reactive oxygen species and activation of caspase-31, and 6-gingerol inhibited pulmonary metastasis bearing B16F10 melanoma cells through the activation of CD8+ T-cells. 6-gingerol has anti-tumoral activity through induction of reactive oxygen species, which also triggers activation of tumour suppressor p53 and the cell cycle arrest and apoptosis.
Ethanolic extract, of ginger, prevent microbial growth. Ginger has antimicrobial activity against E. coli, Salmonella typhi, and Bacillus subtilis. Gingerol and shagelol are the active agents. The ethanolic extract of ginger powder and gingerol effectively inhibits Candida albicans. 6-gingerol and 12-gingerol, from ginger rhizome, is active against periodontal bacteria. 10-gingerol is an active inhibitor of Mycobacterium avium and M. tuberculosis.