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At least 19 recordsLinked to original sources
PubMed2026

Assessment the Effects of Roasted and Non-Roasted Coffee Extracts on Colon Cancer Cells.

Coffee extracts contain numerous bioactive compounds. Given the dietary link between coffee consumption and colorectal cancer, this study compared the effects of roasted and green (unroasted) coffee extracts on human colorectal cancer cells (HCT116) and non-cancerous fibroblasts (BJ-5ta) to evaluate how processing influences proliferation and molecular signaling. Real-time cell analysis (RTCA), qRT-PCR, and label-free quantitative proteomic analysis were performed to assess cellular responses. MTS and RTCA showed that in BJ-5Ta fibroblasts, coffee extracts increased proliferation in the order CNR < CAR < CAU < CNU, whereas the trend was reversed in HCT116 cancer cells. Proteomic analysis revealed that in BJ-5Ta cells, unroasted coffee extract caused downregulation of the ribosome pathway, and natural coffee extract caused downregulation of the gap junction pathway, indicating reduced protein synthesis and cell-cell communication as a potential stress-adaptive response. In contrast, in HCT116 cells, unroasted coffee extract upregulated the ribosome pathway. Also, natural coffee extract upregulated the pentose phosphate pathway in HCT116 cells, which may enhance NADPH production and reduce oxidative stress. Current evidence suggests coffee's bioactive compounds may have different effects varying by coffee extract type and their preparation.

Humans↗
PubMed1987

Studies on the estrogenic activity of a coffee extract.

Ethyl ether extracts derived from coffee were tested for in vitro estrogenic and in vivo uterotropic activities. Coffee extracts, unlike tea and cocoa, were found to actively compete with 17 beta-estradiol for uterine cytosol binding sites. The biologically active fractions possessed an unique ultraviolet absorbance spectrum that excluded them from containing flavonoid, coumestan, or resorcyclic acid lactone constituents. Coffee extracts administered to immature female mice for 3 d in feeding studies displayed significant (p less than 0.05) uterotropic responses, which were similar to results obtained in mice treated with a standard 17 beta-estradiol dose. Additional studies in mice disclosed that coffee extracts did not reduce the uterotropic effect normally induced by 17 beta-estradiol when administered simultaneously with estradiol. The complete estrogenic effects of coffee constituents, coupled with their failure to inhibit a biological response evoked by estradiol, strongly suggest that coffee contains constituent(s) that are weakly estrogenic.

Animals↗
PubMed1987

Coffee extracts inhibit platelet aggregation in vivo and in vitro.

The effect of aqueous coffee extracts on platelet aggregation in humans (in vitro) and rabbits (both in vitro and in vivo) was investigated. Coffee extracts were found to have anti-aggregatory effects on in vitro platelet aggregation induced by ADP or arachidonate but not by collagen. Coffee extracts were also effective after intravenous administration in rabbits. The compound(s) responsible for these effects are water-soluble, heat-resistant, appeared to be different from salicylates, and might also be due to unidentified compounds besides nicotinic acid or known xanthines. Coffee extract and selected fractions decreased the conversion of [14C]-arachidonic acid to thromboxane B2 by the platelets. These studies show that coffee extracts contain compounds which are active in inhibiting platelet aggregation, a critical step involved in thrombosis and other vascular disorders.

Adenosine Diphosphate↗
PubMed1986

[Effect of roasting on the chromatographic profile obtained by gel filtration of Arabian coffee extract].

Gel filtration chromatography under a high pressure system was used to investigate green and roasted coffee aqueous extracts. Chromatographic columns used were of the type TSK-PW 4000, in series. Chromatography of the extracts was monitored either using a refractive index (RI) detector in series with an ultraviolet (UV) detector at 420 nm or with two UV detectors at 280 and 325 nm, respectively. The utilization of RI detection showed significant differences in the molecular weight profile between green and roasted coffees. UV detection at 280 and 325 nm revealed similar chromatographic patterns, suggesting that phenolic compounds were probably bound to proteins. Pigment formation after roasting was monitored by detection at 420 nm, showing that colored material was distributed throughout the molecular weight range studied. The method provided a more rapid analysis compared to traditional gel filtration chromatography and proved to be useful for monitoring changes in molecular weight profile which occur during coffee roasting.

Chromatography, Gel↗
PubMed2026

Furanic compounds in different coffee extraction systems: Analysis of the main influencing factors and correlation with acrylamide.

This study investigates how different coffee types representative of distinct roast profiles and brewing methods jointly affect the occurrence of furanic compounds and acrylamide in brewed coffee. Coffees were prepared using eight extraction methods (AeroPress, Clever, Chemex, French Press, Moka, Pure Brew, Turkish and V60). Five furanic compounds (furfural, furfuryl acetate, 5-methylfurfural, furfuryl alcohol and 5-hydroxymethylfurfural) were quantified in coffee powders and brews by HS-SPME-GC-MS, while acrylamide was determined by UHPLC-MS/MS. Moka and Turkish brews consistently exhibited the highest concentrations of furanic compounds, whereas paper-filtered pour-over methods (V60 and Chemex) showed the lowest levels. Pearson correlation analysis revealed coffee-dependent relationships between furanic compounds, acrylamide and extraction parameters with the strongest associations observed in dark-roasted coffee, reflecting advanced Maillard reaction chemistry. Overall, these results demonstrate that contaminant levels arise from the combined effects of intrinsic coffee chemistry and brewing mechanics and support targeted mitigation strategies: such as roast selection and brewing method optimization.

Acrylamide↗
PubMed1977

[Studies on coffee and coffee substitutes. XIX. Dependence of the quantity of a highly polymeric galactomannan on the degree of extraction coffee-extracts (author's transl)].

In extracts of Columbia Arabica Coffee the content of galactomannan precipitable with alcaline copper solution decreases slowly up to an extraction yield of 43.6%; it decreases somewhat more rapidly with higher extraction yields. An extract of Angola Robusta Coffee showed opposite behaviour. In this case the content of galactomannan increased with the extraction yield, although not evenly. Calculated on the basis of roasted coffee solids the extract of the Arabica coffee had a rather limited range precipitable polysaccharide, the Robusta coffee in contrast with rated increased amounts of galactomannan. The different behaviour of the two coffee varieties may be due to mote or less strong binding of this high-polymer carbohydrate to the cell wall.

Cell Wall↗
PubMed1991

Acute ventilatory response to green coffee dust extract.

The lung function response to inhalation of an extract of green coffee was studied in ten healthy subjects who were prescreened for airway hyperresponsiveness to an aerosol of green coffee extract. The effects of this provocation were evaluated at rest and following moderate exercise as well as with and without pretreatment with 80 mg of disodium cromoglycate (DSCG). There was a statistically significant decrement in lung function over time (P less than .001) following coffee provocation both at rest and following exercise. No significant protection against this response was observed with DSCG pretreatment. While the majority of these "healthy" coffee reactors exhibited baseline nonspecific airway hyperresponsiveness to methacholine (PC20 FEV1 less than 25 mg/mL in 7/10), there was no correlation in these ten subjects between baseline responsiveness to methacholine and the degree of lung function decrement following coffee (P greater than .05). Also, no correlation was observed between skin prick and lung function response to coffee extract. We conclude that inhalation of green coffee extract causes significant bronchoconstriction in selected healthy volunteers and that this response is not prevented by pretreatment with DSCG.

Adolescent↗
PubMed1983

Pharmacological characterisation of extracts of coffee dusts.

The contractile or relaxant activities or both of aqueous extracts of green and roasted coffees were assayed on isolated guinea pig tracheal spirals. Contractile and relaxant activities were compared with histamine and theophylline, respectively. Green coffee extracts induced concentration dependent contraction, but the maximal tension never exceeded 76.3% +/- 5.2 of a maximal histamine contraction (0.69 +/- 0.07 g/mm2 v 0.52 +/- 0.05 g/mm2; p (0.01). One gram of green coffee dust had a biological activity equivalent to 1.23 +/- 0.1 mg of histamine. The pD2 value of histamine was -5.17 +/- 0.05. The potency of green coffee was unaffected by mepyramine maleate (1 micrograms/ml, final bath concentration) while that of histamine was reduced 500 fold. Tissues contracted with histamine were not significantly relaxed by green coffee extracts. By contrast, roasted coffee extracts induced concentration dependent relaxation of uncontracted and histamine contracted tissues. Tissues contracted with green coffee extracts were also completely relaxed by roasted coffee extracts. The pD2 value of theophylline was -4.10 +/- 0.03. The relaxant activity of 1 g of roasted coffee was equivalent to 1.95 +/- 0.16 mg of theophylline. The potency of these extracts was significantly reduced after propranolol (1 micrograms/ml; dose ratio 1.56). Our results show that coffee dust extracts have considerable biological activity which changes from a contractile to a relaxant action as a consequence of processing. The greater incidence of adverse reactions to green coffee dust(s) in coffee workers may be related to the contractile activity present in green coffee dust.

Animals↗
PubMedDate not supplied

Caffeine as main interfering compound in radioimmunoassay of aflatoxin B1 in coffee samples.

The content of caffeine in coffee extracts prepared for radioimmunoassay of aflatoxin B1 was determined by gas chromatography. The extracts from coffee beans and decaffeinated coffee contained 1.76-4.60 and 0.71-0.85 g caffeine/kg, respectively. These concentrations of caffeine caused false results in radioimmunoassay of aflatoxin B1 in the range 1.0-2.8 micrograms/kg for coffee beans and 0.3-0.4 micrograms/kg for decaffeinated coffee.

Aflatoxin B1↗
PubMed1989

Inhibition of in vivo genotoxicity by coffee.

The possible role of coffee in modulating the in vivo genotoxicity of the well established genotoxic chemicals, mitomycin C, cyclophosphamide, procarbazine and adriamycin, was evaluated. Coffee was administered orally to mice that received the genotoxic chemicals ip. Genotoxicity was assessed in the bone-marrow micronucleus test. Doses of coffee in the range 225 to 1125 mg (dry weight)/kg body weight caused significant reductions in the in vivo genotoxicity of mitomycin C, cyclophosphamide and procarbazine but not adriamycin. The inhibitory effect was significant when the coffee was given about 2 hr before the genotoxin; there was a lesser effect when coffee was given together with the genotoxin but there was no inhibition when coffee was given 2-4 hr after the genotoxin. An experiment with mitomycin C demonstrated that the reduction in genotoxicity was dependent on the coffee dose. The inhibition of genotoxicity by coffee was observed in bone-marrow cells sampled 24, 48 or 68 hr after injecting cyclophosphamide. Freshly brewed coffee extract, standard instant coffee, decaffeinated instant coffee and freeze-dried home-brew coffee all exerted inhibitory effects.

Analysis of Variance↗
PubMed1986

Suppressive effects of coffee on the SOS responses induced by UV and chemical mutagens.

SOS-inducing activity of UV or chemical mutagens (AF-2, 4NQO and MNNG) was strongly suppressed by instant coffee in Salmonella typhimurium TA1535/pSK1002. As decaffeinated instant coffee showed a similarly strong suppressive effect, it would seem that caffeine, a known inhibitor of SOS responses, is not responsible for the effect observed. The suppression was also shown by freshly brewed coffee extracts. However, the suppression was absent in green coffee-bean extracts. These results suggest that coffee contains some substance(s) which, apart from caffeine, suppresses SOS-inducing activity of UV or chemical mutagens and that the suppressive substance(s) are produced by roasting coffee beans.

4-Nitroquinoline-1-oxide↗
PubMed1985

[Quinic acid lactone in coffee].

Quinic acid and its lactone (quinide) have been determined in coffee by capillary gas chromatography. No quinide could be detected in 14 green coffee's. After steaming of 4 green coffee's the content of quinic acid was always higher, but no quinide had been formed. During roasting, the latter can be detected when roasting loss exceed 6.5%. It increases approximately proportionally with quinic acid and amounts to 50% of the latter at 22% roasting loss. Both constituents decrease at unusual high roasting loss. In 13 commercial blends of roast coffee 2.4-6.4 g/kg quinide and 8.7-16.6 g/kg quinic acid were present. Especially high values were found in one Espresso type blend and high values in steamed and decaffeinated coffee's. In 11 commercial coffee extracts 2.0-23.2 g/kg quinide and 24.6-36.4 g/kg quinic acid were determined. At higher extraction yield, more quinic acid and quinide is formed, but at very high extraction yield the content of quinide is diminished. During holding of coffee brews at elevated temperature, quinide is slowly hydrolysed.

Chromatography, Gas↗
PubMed1983

[Anaphylaxis following ingestion of coffee, chronic urticaria and analgesics idiosyncrasy].

In a 45-year-old woman with chronic urticaria anaphylactoid reactions occurred after (1) ingestion of coffee and (2) taking an analgesic drug. Prick testing in the patient and passive cutaneous anaphylaxis with coffee extract in the monkey Macacus nemestrinus were positive. With regard to further prick tests and oral provocation tests there is conclusive evidence that anaphylactic hypersensitivity to coffee was co-existing with idiosyncrasy to acetylsalicylic acid, indomethacne, metamizole (dipyrone), and caffeine.

Analgesics↗
PubMed1975

A quantitative method for determination of aflatoxin B in roasted corn.

Roasting aflatoxin-contaminated corn will reduce toxin levels. A quantitative analysis for aflatoxin in roasted corn has been developed by modifying a cleanup technique for green coffee extracts approved as official first action by the AOAC. A chloroform extract is partially purified on a Florisil column, and thin layer chromatographic (TLC) plates are developed with methylene chloride-chloroform-isoamyl alcohol-formic acid (81+15+3+1). Recoveries average 101% and the sensitivity limit is 5 ppb aflatoxin B1. A 2-dimensional TLC procedure can also be used to separate the aflatoxins from background interferences.

Aflatoxins↗
PubMed1978

Extraction and analysis of coffee bean allergens.

Workers in the coffee industry can develop occupational allergic disease upon exposure to dust associated with coffee manufacturing. Since controversy exists as to the source or chemical nature of these allergens, the mouse model of reaginic antibody production was used to assess the potential sources of allergens in samples obtained from a local coffee manufacturing plant. Mice were immunized with extracts of coffee dust and beans and the resulting reaginic antibody response determined by the passive cutaneous anaphylaxis reaction. Cross-reacting allergens were detected in samples of coffee dust, cleaner can debris and green coffee beans, but not in chaff or roasted coffee beans. None of the allergens detected in coffee samples cross-reacted with extract of castor beans, although these extracts contained the potent castor bean allergen. Green coffee bean allergens partially purified by gel filtration were heterogeneous with respect to molecular size, although quite similar in their reactivity with reaginic antiserum. These results suggest that the green coffee bean is the major source of allergen in coffee manufacturing plants. This allergen is heterogeneous with respect to size and heat lability, and is immunochemically different from the castor bean allergen.

Allergens↗