Apoptosis-mediated proliferation inhibition of human colon cancer cells by volatile principles of Citrus aurantifolia
Introduction
Colon cancer is one of the most prevalent cancers throughout the world and especially in the western countries. This is continuously increasing worldwide due to rapid changes in dietary pattern and preferences. Many epidemiological studies indicated that western-style diet, primarily, the consumption of red meat, is positively associated with a high colon cancer incidence (Abeysinghe et al., 2007). Continuous efforts are being made for search of novel source of bioactive compounds to prevent colon carcinoma. In this direction, bioactive compounds of natural origin, particularly from a dietary source, are gaining significance. In the recent years, citrus has gained importance due to their ability to provide multitude health benefits not only from vitamin-C but also from other bioactive compounds. Our group has been involved with citrus research over a decade, mainly focusing on the identification of a wide array of novel bioactive compounds such as flavonoids, phenolics, limonoids and phytosterols (Jayaprakasha et al., 2006, Jayaprakasha et al., 2007, Raman et al., 2004). Other investigations from our laboratory have also provided evidences for health-promoting properties of these compounds, such as in vitro antioxidant activity, prevention of cancer, in animal and cell culture studies (Jayaprakasha et al., 2008, Jayaprakasha et al., 2007, Jayaprakasha et al., 2008). Our research has also demonstrated that citrus bioactive compounds are capable of inhibiting human neuroblastoma and colon cancer cells (Poulose, Harris, & Patil, 2006). An animal study has revealed that freeze–dried grapefruit juice powder (13.7 g/kg) and its bioactive compounds naringin and limonin (200 mg/kg) are capable of inhibiting aberrant crypts through the suppression of cyclo-oxygenase-2 and inducible nitric oxide synthase (iNOS) in azoxymethane-treated animals (Vanamala et al., 2006).
Lime [Citrus aurantifolia (Christm.) Swingle] is a polyembryonic species with greenish yellow, smooth surfaced, thin-skinned fruits, and solid core at maturity with highly acidic juice. Limes are cultivated across the globe mostly in hot subtropical or tropical regions such as Southern Florida in USA, India, Mexico, Egypt, and West Indies (Morton, 1987). Both juice and volatile oils are the major commercial products of lime, and volatile oil is widely used as a flavouring agent in beverages and food products (Chamblee, Karelitz, Radford, & Clark, 1997). Pharmaceutical industries also use lime volatile oil as a flavouring agent in syrups and suspensions (Porta, Reverehon, & Barth, 1997). In perfumery, lime volatile oils have been used as a base for many compositions, which have a higher market value per pound than other citrus varieties such as orange, grapefruit, or tangerine volatile oils. Some of the reported chemical compositions of lime volatile oil consists of d-limonene, α-terpineol, 4-terpineol, 1,4-cineole, 1,8-cineole, p-cymene, β-pinene, β-bisabolene, citral, geranial and neral (Ranganna, Govindrajan, & Ramana, 1983). Recently, some more additional flavour compounds such as neryl acetate, α-bergamotene, valencene and germacrene-D have been reported (Veriotti & Sacks, 2001). Kaffir lime (Citrus hystrix) volatile oil has been demonstrated to reduce blood pressure and relieve depression in human studies (Hongratanaworakit & Buchbauer, 2007), which provides strong evidence on potent health benefits of citrus volatile oils. The above studies have demonstrated that citrus fruits and their bioactive compounds have a significant role in human disease prevention. However, the antiproliferative activity of lime volatile oil has never been explored. In this context, study was conducted to analyse the chemical composition of the lime volatile oil by GC–MS. Further, potential of antiproliferative mechanism on cultured human adenocarcinoma cells has been studied for the first time.
Section snippets
Chemicals and reagents
All the chemicals used were of analytical grade and procured from Sigma (St. Louis, MO, USA). d-Limonene, β-linalool, α-terpineol, C8–C20 n-alkanes and α-pinene were obtained from Sigma (St. Louis, MO, USA). Reagents and media used for cell culture studies were of molecular biology grade and purchased from Hyclone (Logan, UT, USA) and Mediatech Inc. (Manassas, VA, USA). Caspase-3 kit was purchased from BD Pharmingen (San Jose, CA, USA). All the reagents for immunoblotting were from Bio-Rad,
Results and discussion
Lime volatiles are well known for their application in pharmaceuticals and cosmetics. However, there are no reports on health benefits; this may be due to the lack of scientific evidences. In this context, the present study is an attempt to understand the chemical composition of lime volatile oil and, possible mechanism of inhibition of colon carcinoma using cell culture model has been demonstrated for the first time.
Conclusions
Twenty-two volatile components were identified from Citrus aurantifolia using GC–MS. The major compounds were found to be d-limonene, d-dihydrocarvone, verbena, β-linalool, α-terpinol, trans-α-bergamotene. For the first time, we have demonstrated the principles of volatile oil that can induce apoptosis-mediated cells death in human colon adenocarcinoma cells. Induction of apoptosis by lime volatile oils was supported with evidence of DNA fragmentation, elevated caspase-3 content and expression
Acknowledgements
This project was funded by the USDA-Designing Foods for Health through the Vegetable & Fruit Improvement Center, TAES 06-118409. First author would like to acknowledge Honourable Vice-chancellor, University of Agriculture Sciences, Dharwad, India, for providing the opportunity to conduct research at the VFIC, Texas A&M University, College Station, TX, USA.
References (39)
- et al.
Bioactive compounds and antioxidant capacities in different edible tissues of citrus fruit of four species
Food Chemistry
(2007) - et al.
Effects of acute caffeine administration on NOS and Bax/Bcl2 expression in the myocardium of rat
Pharmacological Research
(2008) - et al.
Cluster and principal component analysis for Kovats’ retention indices on apolar and polar stationary phases in gas chromatography
Journal of Chromatography A
(2008) - et al.
Thymoquinone: A promising anti-cancer drug from natural sources
The International Journal of Biochemistry and Cell Biology
(2006) - et al.
Antioxidant capacity of pummelo and navel oranges: Extraction efficiency of solvents in sequence
LWT – Food Science and Technology
(2008) - et al.
Inhibition of colon cancer cell growth and antioxidant activity of bioactive compounds from Poncirus trifoliata (L) Raf
Bioorganic and Medicinal Chemistry
(2007) - et al.
Novel triterpenoid from Citrus aurantium L. possesses chemopreventive properties against human colon cancer cells
Bioorganic and Medicinal Chemistry
(2008) - et al.
Curcumin for chemoprevention of colon cancer
Cancer Letters
(2007) - et al.
Taxonomical contribution of essential oils in mandarins cultivars
Biochemical Systematics and Ecology
(2004) - et al.
In vitro evaluation of the anticancer effect of lactoferrin and tea polyphenol combination on oral carcinoma cells
Cell Biology International
(2007)
Characterization of advanced glycation end products for biochemical studies: Side chain modifications and fluorescence characteristics
Analytical Biochemistry
Volatile flavour components of orange juice obtained from the cv
Kozan of Turkey. Journal of Food Composition and Analysis
Identification of essential oils by ion trap mass spectrometry
Identification of sesquiterpenes in citrus essential oils by cryofocussing GC/FT-IR
Journal of Essential Oil Research
Human metabolism of the experimental cancer therapeutic agent d-limonene
Cancer Chemotherapy and Pharmacology
Gas chromatographic retention indices of monoterpens and sesquiterpenes on methyl silicone and carbowax 20M phases
Journal of Chromatography
Mouse skin tumor promoting activity of orange peel oil and d-limonene: A re-evaluation
Carcinogenesis
The inhibition of protein prenyltransferases by oxygenated metabolites of limonene and perillyl alcohol
Cancer Letters
Limonene-induced regression of mammary carcinomas
Cancer Research
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