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- Author or Editor: G.K. Jayaprakasha x
Open column chromatography is an effective and common technique for the separation and purification of chemical constituents. Limonoids are found in significant quantities in citrus fruits. Citrus limonoids have documented anti-cancer activity in several types of cancer, such as breast, colon, skin, and neuroblastoma in animal models and in vitro cell culture studies. Furthermore, limonoids have shown anti-inflammatory properties and inhibitory effects on bone resorption. In addition to many potential health benefits, limonoids have also shown antifungal and insect anti-feedant properties. To meet the large demand of limonoids for bioactivity studies, defatted grapefruit seeds were extracted using acetone and concentrated under vacuum. The dried extract was loaded onto a silica gel column and eluted with mixtures of dichloromethane and ethyl acetate with increasing polarity to obtain three compounds. The purity of the compounds (1–3) have been analyzed by HPLC and the structures have been identified by using NMR spectra and mass spectra as nomilin, limonin, and deacetylnomilin, in respective order of elution. The results will be presented in greater detail on the poster. This project is based upon work supported by the USDA-CSREES under Agreement USDA IFAFS #2001 52102 02294 and USDA #2005-34402-14401 “Designing Foods for Health” through the Vegetable & Fruit Improvement Center.
Citrus consumption has been shown to promote human health due to presence of several bioactive compounds. In the process of understanding the health benefits of citrus, we need to isolate and characterize these compounds. Limonoids are one of such prominent, but lesser-known phytonutrients that have been shown to prevent cancers of the mouth, skin, lung, breast, and colon. With the growing interest in the health-promoting properties of citrus limonoids, the demand for these bioactives has significantly increased. It has been critical to explore environment-friendly extraction methods rather than using hazardous organic solvents. A water-based hydrotropic extraction of limonoid aglycones from sour orange (Citrus aurantium L.) seeds was developed. Two hydrotropes, sodium salicylate (Na-Sal) and sodium cumene sulfonate (Na-CuS), were studied for extraction efficiency using the Box Behnken experiment design method. The extraction efficiency of prominent aglycone limonin was observed depending on hydrotrope concentration, extraction temperature, and percentage of raw material loading. Response Surface Analysis (RSA) of data predicted the optimum conditions for maximum yield. Recovery of aglycones from filtered extract is also easily achieved by mere dilution using water at pH 3 or 7 or by partitioning the extract with dichloromethane. At optimum conditions, limonin yield of 0.46 mg/g seeds in the case of Na-Sal extraction and 0.65 mg/g seeds in the case of Na-CuS extraction was achieved. The results demonstrated that the hydrotropic extraction process of limonoid aglycones has practical commercial importance. This project is based upon work supported by the USDA–CSREES IFAFS #2001 52102 02294 and USDA–CSREES #2005-34402-14401 “Designing Foods for Health” through the Vegetable and Fruit Improvement Center.
Grapefruit has potential health-promoting properties due to the presence of multitude bioactive compounds. Ongoing cell culture and animal studies in our lab using limonoids and flavonoids have provided strong evidence of their protective properties for preventing chronic diseases. Studies related to D-glucarate, a natural, nontoxic bioactive compound found in grapefruit, has not been explored. One of the derivatives, such as D-glucaro-1,4-lactone, is reported to be a potent ß-glucuronidase inhibitor. With the inhibition of ß-glucuronidase enzyme, glucuronidation will be favored. Glucuronidation is a conjugation process through which potentially carcinogenic environmental toxins can be neutralized. In this context, quantification of glucarate using HPLC was developed. Samples from grapefruits were prepared by heating fruit extract with distilled water. Further, the extract was homogenized and centrifuged. The supernatant was treated with petroleum ether to remove non-polar substances. Then the extract was subject to ion exchange chromatography. Fractions were collected and analyzed by analytical HPLC for the quantification of D-glucarate content and its lactone. This project was supported by the USDA-CSREES grant for Designing Foods for Health through the Vegetable and Fruit Improvement Center.
Our recent studies have shown that certain citrus limonoids protect from colon cancer based on cell and animal studies. Animal studies also suggest that citrus juice protects from osteoporosis. To understand the structure–function relationship through animal studies requires a large amount of purified limonoids. Since certain limonoids are present in low concentration, it is a challenge to obtain the required quantity of different limonoids. In this context, we report the purification of limonin 17-ß-D glucopyranosides (LG), and deacetylnomilinic acid 17-ß-D glucopyranoside (DNAG). However, DNAG was isolated in relatively large amount from sour orange (Citrus aurantium L.) seeds. Defatted seed powder was extracted with methanol and purified using column chromatography to obtain multigrams of DNAG. While LG was found in lower concentration, a large concentration of hesperidin was also purified in this process. This project is based upon work supported by the USDA-CSREES under Agreement USDA IFAFS #2001 52102 02294 and USDA #2005-34402-14401 “Designing Foods for Health” through the Vegetable & Fruit Improvement Center.
Food and drug interaction has been under discussionm and specifically grapefruit and drug interaction has been under investigation, in recent years. Irradiation of food has multiple benefits in food preservation through several processes, such as sprout inhibition, disinfection, decontamination, delayed maturation, and sterilization. When ionizing radiation is passed through food, it may affect the functional components, including organoleptic characteristics. In addition to naringin, dihydroxybergamottin, paradisin A, and bergamottin, as well as their isomers, are considered putative bioactive furocoumarins present in the grapefruit juice, which interfere with the first pass metabolism of the drugs. These compounds inhibit the activity of CYP P450 3A4 and P-glycoprotein, which, in turn, will increase bioavailability of certain medications. In order to investigate the effect of pre-and postharvest practices on furocoumarins, `Rio Red' and `Marsh White' grapefruits were irradiated with 1, 5, and 10 kGys of e-beam. The irradiated fruit juice was analyzed for qualitative and quantitative changes in furocoumarins. Fifty milliliters of grapefruit juice was extracted with ethyl acetate three times and ethyl acetate extract was dried under vacuum and analyzed by HPLC. Irradiation at 1 kGys showed a decrease in the total content of dihydroxybergamottin, paradisin A, and bergamottin compared to 5 kGys, 10 kGys, and control. This project is based upon work supported by the USDA-CSREES under Agreement USDA IFAFS # 2001 52102 02294 and USDA # 2005-34402-14401 “Designing Foods for Health” through the Vegetable & Fruit Improvement Center.
Irradiation of fruit and vegetables can potentially be used by industry as a quarantine method to contain insect pests, microorganisms, and to extend shelf life. Gamma, electron beam, and ultraviolet radiation are the most frequently used radiation techniques. These radiation treatments have an effect on bioactive compounds. Grapefruit juice contains bioactive compounds such as limonoids, flavonoids, and furocoumarins. Bioactive furocoumarins in grapefruit juice have been found to increase the bioavailability of many drugs. Bergamottin, dihydroxybergamottin, and paradisin A are major furocoumarins that are shown to inhibit the activity of CYP P450 3A4 and P-gylcoprotein, which are involved in the first pass metabolism of drugs in the gut. This results in a dose-dependent increase of the drug beyond what is intended. Furocoumarins are photoreactive compounds and will readily react to ultraviolet radiation. The effect of various doses of ultraviolet radiation was investigated on `Rio Red' and `Marsh White' grapefruit. Grapefruit juice (50 mL) was irradiated with Ultraviolet A, B, and C radiation for either 5 or 10 min. Treated and control juice was extracted with 100, 50, and 50 mL of ethyl acetate. The extract was then dried and reconstituted with methanol and filtered through a 0.4-μm PTFE membrane filter. The methanol extracts were analyzed by HPLC and the concentrations of bergamottin, dihydroxybergamottin, and paradisin A were compared for UVA, UVB, UVC, and control. This project is based upon work supported by the USDA-CSREES under Agreement USDA IFAFS # 2001 52102 02294 and USDA # 2005-34402-14401 “Designing Foods for Health” through the Vegetable & Fruit Improvement Center.
Consumption of fruits and vegetables has been associated with reduced risk of disease, such as neurodegenerative disorders and certain forms of cancer, and aging. Antioxidants prevent the damage to macromolecules and cells by interfering with the free radicals. Several natural compounds that posses antioxidant activity have been reported from plant sources and are commercially promoted as nutraceuticals. Citrus fruits contain certain bioactive compounds such as phenolics, flavonoids, limonoids, carotenoids, and ascorbic acid. In this context, navel oranges were freeze-dried and extracted with five different solvents, such as hexane, ethyl acetate, acetone, methanol, and 8 methanol: 2 water. The extracts were dried under vacuum and screened for their radical scavenging activity using the 1,1-diphenyl-2-picrylhydrazyl method at 250, 500, and 1000 ppm. The methanol: water and methanol extracts of navel orange were found to be maximum (92.9%) and minimum (63.89%) radical scavenging activity at 1000 ppm. Furthermore, the antioxidant capacity of all extracts was assayed through the phosphomolybdenum method and expressed as equivalent to ascorbic acid (μmol/g of the extract). The order of antioxidant capacity for navel orange extracts was found to be ethyl acetate > acetone > methanol: water > methanol > hexane. It seems that the antioxidant capacity of the extracts is in accordance with the amount of phenolics/lycopene present in each fraction and may provide a good source of antioxidants. This project is based upon work supported by the USDA–CSREES under Agreement USDA IFAFS #2001-52102-02294 and USDA #2005-34402-14401 “Designing Foods for Health” through the Vegetable and Fruit Improvement Center.
Diets rich in vegetables and fruits are known to be protective against several diseases. Only a limited number of vegetables and fruits are consumed as part of the daily diet in Western countries. Historically, indigenous vegetables and fruits are known for their medicinal and nutritional value in countries where they were originated and/or domesticated. However, relatively few systemic studies and reviews were conducted to enumerate the potential of these vegetables to human health benefits. Although certain indigenous crops have received attention, the majority of these crops with strong potential biological activities were neglected and/or not reported. Considering the current health-related problems and obesity-related diseases, it is timely to enumerate the health-promoting properties of certain indigenous vegetables. In this report, we have reviewed some of the important crops indigenous to Southeast Asia and their potential health-promoting properties.
Grapefruit juice contain furanocoumarin derivatives which are known to interact with various drugs such as felodipine, leading to the increased bioavailability. Due to very low concentrations of furocoumarin in grapefruit juice, isolation of these compounds has been a challenge to researchers. Five grapefruit (Citrus paradisi Macf.) varieties such as `Marsh White', `Duncan', `Rio Red', `Orange Flesh', and `Mexican Red' were harvested and analyzed. Samples were extracted successively three times with ethyl acetate until all furocoumarins were extracted. The dried extract was reconstituted in methanol and used for quantification using high-performance liquid chromatography. Furanocoumarins were quantified by gradient elution with methanol and water as mobile phase with a flow rate of 1.1 mL/min at 240 nm. The concentrations of bergamottin, dihydroxybergamotin (DHB) and dimer of DHB were shown to distinctly differ among varieties. Red colored grapefruit showed lower concentrations of the furocoumarins compared to white colored grapefruit. Among the five varieties, `Rio Red' grapefruit contain lower concentrations of bergamottin and DHB. Further studies are continued to quantify other dimers and commercial varieties. Knowledge of furocoumarin levels in grapefruit may eventually help the consumer to make decision about eating grapefruit and/or drinking juice while taking certain medications.
Citrusprovedbeneficial to human health in preventing cardiovascular disorders, hypertension, anemia, and several cancers, including colon, lung, skin, stomach, and breast, in animal and cell culture studies. For the first time, current study was focused to determine whether orange juice and grapefruit juice increase bone mass in an orchidectomized (ORX) rat model of osteoporosis. Thirty-six male Sprague-Dawley rats were randomly divided into four groups of 1) sham; 2) ORX; 3) ORX + orange juice (OJ); and 4) ORX + grapefruit juice (GJ). All rats were fed to the mean intake of the sham group and were provided with freshly squeezed grapefruit or orange juice for 60 days. There was a numerical improvement in femoral density with OJ and GJ compared to the ORX group. Ultimate bone strength and femoral cortical area diameter (mm) increased (P < 0.05) with OJ and GJ compared to the ORX group. Furthermore, bone fracture withstand threshold time(s) increased (P < 0.05) with OJ and GJ compared to the ORX group. Beneficial effects of citrus juices on bone strength could be related to its bioactive triterpene compounds and nutrient composition. Isolation of triterpenes using specific combinations of food-grade adsorbent and ion exchange resins yielded pure limonin-17-β-D-glucoside and limonin along with obacunone, nomilin, and deacetylnomilin. Identification and characterization of the isolated limonoids were performed by specific analytical techniques, such as HPLC, LC-MS, and NMR. Further studies are needed to determine the protective effects of limonoids on bone homeostasis. Funded by USDA 2001-52102-11257 and 2004-34402-14768.