Cancer chemoprevention with garlic and its constituents. Cancer Lett

Uttar Pradesh Dental College and Research Centre, Lakhnau, Uttar Pradesh, India
Cancer Letters (Impact Factor: 5.62). 04/2007; 247(2):167-81. DOI: 10.1016/j.canlet.2006.05.009
Source: PubMed


Advance metastasized cancers are generally incurable; hence an effort to prolong the process of carcinogenesis through chemoprevention has emerged consistent with this notion. In recent years, a considerable attention has been placed to identify naturally occurring chemopreventive substances capable of inhibiting, retarding or reversing the process of carcinogenesis. A number of phenolic substances, particularly those present in dietary and medicinal plants, have been shown to possess substantial anticarcinogenic and antimutagenic activities. Epidemiological observations and laboratory studies, both in cell culture and animal models have indicated anticarcinogenic potential of garlic and its constituents, which has been traditionally used for varied human ailments around the world. Chemical analysis has indicated that protective effects of garlic appear to be related to the presence of organosulfur compounds mainly allyl derivatives. Several mechanisms have been presented to explain cancer chemopreventive effects of garlic-derived products. These include modulation in activity of several metabolizing enzymes that activate and detoxify carcinogens and inhibit DNA adduct formation, antioxidative and free radicals scavenging properties and regulation of cell proliferation, apoptosis and immune responses. Recent data show that garlic-derived products modulate cell-signaling pathways in a fashion that controls the unwanted proliferation of cells thereby imparting strong cancer chemopreventive as well as cancer therapeutic effects. This review discusses mechanistic basis of cancer chemopreventive effects of garlic-derived products, their implication in cancer management and ways and means to take these agents from bench to real life situations.

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    • "Also, several mechanisms of action responsible for the cancer preventive effects have been proposed. These include inhibition of mutagenesis by inhibiting metabolism, inhibition of DNA adduct formation, free-radical scavenging, and effects on cell proliferation and tumour growth through apoptosis signalling [24]. In the present study, the in vitro antioxidant and anticancer activities as well as phytochemical constituents of Ageratum conyzoides, using crude aqueous extracts of the plant, and its parts (leaves, flowers, and stem) were reported for the first time. "
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    ABSTRACT: Ageratum conyzoides, an annual herb, has been used in folklore for managing of a wide range of diseases including cancer. However, the safety and effectiveness of this medicinal plant is poorly evaluated. The intention of this study was to evaluate the in vitro antioxidant and anticancer activities of aqueous leaf, flower, stem and whole plant extracts of A. conyzoidesas well as the qualitative phytochemical constituents. The DPPH, Folin-Ciocalteau and glutathione assays were used to evaluate the plant's antioxidant potential. The in vitro 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay was exploited for determination of in vitro anticancer activity against four selected human cell lines: leukemic (Jurkat), prostate (LNCap), breast (MCF-7), and normal prostate (PNT2). Curcumin was used as standard anticancer compound. The selectivity index (SI) for each extract was also estimated. The extracts scavenged DPPH in a dose dependent manner compared to the positive control, butylated hydroxy toluene (BHT). The leaf extract was the strongest scavenger of DPPH free radical, EC50 value of 0.091 ± 0.024mg/ml, and also recorded the highest total phenol content of 1678.86 ± 40.67 mg/g GAE. However, glutathione was not detected in any of the crude extracts. The cytotoxicity exhibited by the aqueous leaf extract was weak on Jurkat cells with IC50 value of 408.15±23.25 μg/ml, and inactive to the remaining cancer cell lines. Moreover, the other extracts showed weak or no activities on the cancer cell lines. All extracts were not cytotoxic to the normal prostate (PNT2) cell line. The leaf extract was selective against Jurkat cell lines with SI value of 2.5, a little higher than curcumin (SI = 2.3). The presence of tannins, saponins and terpenoids were concentrated in the leaf and flower extracts of the plant. The present investigations suggest that Ageratum conyzoides aqueous extracts possess remarkable antioxidant effects, and weak anticancer properties. The phytochemical compounds detected could be responsible for these properties. Further studies should be conducted to unravel the active chemical principle(s).
    Full-text · Article · Apr 2015 · Journal of Global Biosciences
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    • "Garlic contains at least thirtythree sulfur compounds, several enzymes, and seventeen amino acids. Additional constituents of intact garlic include steroidal glycosides and lectins [1] [6]. The sulfur compounds are responsible for garlic's pungent odor and many of its medicinal effects [11]. "
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    ABSTRACT: We evaluated the preventive and therapeutic effects of aqueous suspensions of garlic, tomato, and garlic + tomato in the development of experimental Ehrlich tumors in mice. The aqueous suspensions (2%) were administered over a short term for 30 days before tumor inoculation and 12 days afterward, and suspensions at 6% were administered for 180 days before inoculation and for 12 days afterward. The volume, number, and characteristics of the tumor cells and AgNOR counts were determined to compare the different treatments. Aqueous 6% suspensions of garlic, tomato, and garlic + tomato given over the long term significantly reduced tumor growth but when given over the short term, they did not alter tumor growth.
    Full-text · Article · Jun 2014 · Evidence-based Complementary and Alternative Medicine
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    • "Please cite this article in press as: Gıˆtin L, et al., Sulfur compounds identification and quantification from Allium spp. fresh leaves, Journal of Food and Drug Analysis (2014), diseases (e.g., coronary heart disease [6e8], cancer [9] [10], obesity, diabetes, disturbances of the gastrointestinal tract, hypercholesterolemia, and inflammatory diseases [11e13]), because they contain volatile sulfur-containing compounds, which have a distinct flavor and are responsible for the pungent odor. A special class of biologically active organosulfuric compounds, S-alk(en)yl-L-cysteine sulfoxides (such as alliin and g-glutamylcysteines), dominates onion and wild garlic flavor. "
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    ABSTRACT: Background Pyruvic acid concentration is a critical factor in determining Allium spp. pungency. This study was initiated to accurately measure the background pyruvic acid levels in Romanian Allium spp. From the pungency point of view, all analyzed plant varieties in this study are considered low pungent cultivars based on the enzymatically produced pyruvate level (between 42 μmol/g and 222 μmol/g fresh wt). Chromatographic analysis was carried out for the different varieties of the most popular fresh leaves (Allium cepa var. “Diamant”, Allium cepa var. “Rubiniu”, and Allium ursinum L.) in order to identify the sulfur compounds. The thin layer chromatography analysis led to the identification of allicin, with Rf = 0.377–0.47, as an important sulfur compound. The gas chromatography-mass spectrometry analysis of the leaves' extracts detected disulfides as the major sulfur compounds. Principal component analysis was performed to establish the differences in plant composition. These studies suggest the potential good uses of the fresh leaves of Romanian Allium spp. as condiment, ingredient, or preservative in the food industry.
    Full-text · Article · May 2014 · Journal of Food and Drug Analysis
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