Coffee Components Research Articles

Safety Pharmacological Evaluation of the Coffee Component, Caffeoylquinic Acid, and Its Metabolites, Using Ex Vivo and In Vitro Profiling Assays.

Although coffee components have gained interest for use as pharmaceuticals, little is known about their safety pharmacological effects. Hence, we aimed to evaluate the safety pharmacological effects of a chlorogenic acid (CGA)-related compound contained in coffee, 5-O-caffeoylquinic acid (5-CQA), and its metabolites, 5-O-feruloylquinic acid (5-FQA), caffeic acid (CA), and ferulic acid (FA). Langendorff perfused heart assay, electrophysiological assay of acute rat hippocampal slices, and in vitro Magnus assay of gastrointestinal tracts were conducted at 1–100 µM. Moreover, in vitro profiling assays against 38 major targets were conducted. In the Langendorff assay, no significant adverse effects were observed. In the electrophysiological assay, although epileptiform discharge rates were increased at 10 µM CA with 4-aminopyridine, and area under the curve (AUC) and number of population spike were increased at 10 µM FA with bicuculline, dose dependency was not confirmed, and no significant changes were observed at 1 µM and by CGAs alone. In the Magnus assay, a slight increase in contraction activity was observed at >1 µM FA in the stomach fundi and 100 µM 5-CQA in the ileum, suggesting enterokinesis promotion. No significant interactions were observed in the in vitro profiling assays. Therefore, CGAs could have a fundamental function as safe pharmaceuticals.

Removing phenolic pollutants using Deep Eutectic Solvents

Phenolic compounds are present both in nature as components of fruits, coffee or tea, and in wastewaters of many different industries. The world organization WHO, list some of these phenolic compounds as priority pollutants due to their toxicity, so it is necessary to remove them, to a concentration below the legal limit (1 mg·L−1) before wastewater discharge. In this work, six new solvents, Deep Eutectic Solvents (DES) based on organic acids (dodecanoic acid, decanoic acid, octanoic acid) and menthol or thymol, were studied as extraction solvents for these pollutant compounds. Their physical properties (density, viscosity, refractive index and speed of sound) were measured, as well as their capability to remove phenolic compounds (phenol, o-cresol and 2-chlorophenol) from water using liquid-liquid extraction. The experimental data were compared with other results obtained for the extraction phenolic compounds from water using Ionic Liquids. The results obtained show that the use of these new solvents provide a good extraction method for phenolic compounds present in wastewaters. The best results were obtained for menthol based DES to extract o-cresol and 2-chlorophenol, getting extraction efficiencies upper than 85% for all initial concentration of phenolic compound.

Bacillus amyloliquefaciens HZ-12 heterologously expressing NdmABCDE with higher ability of caffeine degradation

Caffeine is a major component of tea and coffee. Apart from the stimulatory effects, cumulative intake of caffeine has caused several diseases. In addition, the presence of caffeine brings out the deterioration of environmental pollution. Therefore, the demand for decaffeinated products, especially decaffeinated coffee and tea, is increasing. However, Pseudomonas putida as the most widely studied bacteria isn't suitable for producing decaffeinated tea and coffee due to the production of an unpleasant odor and endotoxins at the same time. A more appropriate system (Bacillus amyloliquefaciens HZ-12:ndmABCDE) is needed to produce decaffeinated products; and HZ-12:ndmABCDE was constructed by orderly integrating N-demethylase genes (ndmABCDE) in a safer strain HZ-12. Demethylases (NdmABCDE) in P. putida can degrade caffeine to xanthine, which was further degraded to CO2 and NH4+ by the purine metabolic pathway. Finally, HZ-12:ndmABCDE could degrade 52.6% of caffeine in the optimized medium, 31.5% higher than HZ-12; caffeine was demethylated in sequence to form theobromine, paraxanthine, 7-methylxanthine and xanthine; and there are no endotoxins and unpleasant odor. This study provides a safer strain (HZ-12:ndmABCDE) for producing decaffeinated tea and coffee and a new idea that B. amyloliquefaciens HZ-12 can heterologously express the demethylase genes in P. putida.

Impact of drying process on chemical composition and key aroma components of Arabica coffee

Influence of heat pump drying (HP at 40, 45 and 50 °C), tray drying (TD) and sun drying (SD) on the quality of Arabica coffee was evaluated. Drying process did not affect the caffeine content, but influenced levels of some amino acids. Sucrose content was higher in HP and TD than in SD green coffees. The perceived aroma of brewed coffee from SD was similar to HP, but differed from TD. Concentrations of 30 important odorants were compared for SD, HP (50 °C) and TD brewed coffees. 2-Furfurylthiol, a key odorant of coffee, was at the same level in SD and HP coffees and lowest in TD samples. Principal component analysis (PCA) separated SD from HP and TD, based on the concentrations of 23 odorants. Combined results of sensory and chemical analyses showed that in comparison to SD, HP was superior to TD for preserving overall flavor quality.

Effects of Enteric Environmental Modification by Coffee Components on Neurodegeneration in Rotenone-Treated Mice.

Epidemiological studies have shown that coffee consumption decreases the risk of Parkinson’s disease (PD). Caffeic acid (CA) and chlorogenic acid (CGA) are coffee components that have antioxidative properties. Rotenone, a mitochondrial complex I inhibitor, has been used to develop parkinsonian models, because the toxin induces PD-like pathology. Here, we examined the neuroprotective effects of CA and CGA against the rotenone-induced degeneration of central dopaminergic and peripheral enteric neurons. Male C57BL/6J mice were chronically administered rotenone (2.5 mg/kg/day), subcutaneously for four weeks. The animals were orally administered CA or CGA daily for 1 week before rotenone exposure and during the four weeks of rotenone treatment. Administrations of CA or CGA prevented rotenone-induced neurodegeneration of both nigral dopaminergic and intestinal enteric neurons. CA and CGA upregulated the antioxidative molecules, metallothionein (MT)-1,2, in striatal astrocytes of rotenone-injected mice. Primary cultured mesencephalic or enteric cells were pretreated with CA or CGA for 24 h, and then further co-treated with a low dose of rotenone (1–5 nM) for 48 h. The neuroprotective effects and MT upregulation induced by CA and CGA in vivo were reproduced in cultured cells. Our data indicated that intake of coffee components, CA and CGA, enhanced the antioxidative properties of glial cells and prevents rotenone-induced neurodegeneration in both the brain and myenteric plexus.

Mathematical modelling of the steam stripping of aroma from roast and ground coffee

Instant coffee manufacture involves the aqueous extraction of soluble coffee components followed by drying to form a soluble powder. A challenge that arises from the process is the loss of volatile aroma compounds during evaporative drying. One method of retaining aroma is to first steam strip the volatiles from the coffee and add them back to a concentrated coffee solution just before the final drying stage. Understanding the impact of process conditions on the aroma content of the stripped solution offers engineers the ability to target desirable compounds and maximise their yield. This paper presents a multiscale model for aroma extraction that describes: (i) release from the matrix, (ii) diffusion through the coffee grain, (iii) transfer into water and steam, and (iv) advection through the stripping column. Results reveal how aroma physiochemistry determines the limiting kinetics at industrial extraction conditions. The interaction with the soluble matrix can also inhibit extraction, but this effect varies for the different aromas studied.

The Effect of High Temperature Roasted Coffea liberica on Physiological and Histological Structure of Mice’s Kidney

Numerous varieties of coffee, such as robusta, arabica, gayo and etcetera, was made in order to fulfill the needs of its lovers. In Tungkal, Jambi, Liberica coffee was recently discovered and the chemical reactions during roasting process produces several components, which are caffeine, chlorogenic acid, monosaccharides and others, to create a unique flavor as the identity. Unique flavor of Liberica coffee is obtained from the high temperature roasting process and the components in coffee. This research aims to determine the effect of Liberica coffee (Coffea liberica), concentration (0, 8.000, 10.000 and 12.000 ppm/day) on the physiological and histological structure of the mice’s kidney (Mus musculus L.) for 28 days. The results was showed that kidney histological observation of fatty degeneration, tubular swelling, and pyknotic nucleus associated with percentages of renal tubular damage in the control group, P1, P2 and P3 were 0.71±0.96, 4.91±0.17, 5.82±0.21 and 9.01±0.13 indicating low damage (<50%) and liberica coffee does not affect physiological function, such as creatinine level.Keywords : Liberica coffee, kidney, histological

Effects of Supplementation with Main Coffee Components on Hepatic, Metabolic, and Inflammatory Indices in Patients with Non-Alcoholic Fatty Liver Disease and Type 2 Diabetes: A Randomized, Double-Blind, Placebo-Controlled, Clinical Trial

Effects of Supplementation with Main Coffee Components on Hepatic, Metabolic, and Inflammatory Indices in Patients with Non-Alcoholic Fatty Liver Disease and Type 2 Diabetes: A Randomized, Double-Blind, Placebo-Controlled, Clinical Trial

Combining mid infrared spectroscopy and paper spray mass spectrometry in a data fusion model to predict the composition of coffee blends

This paper describes a robust multivariate model for quantifying and characterizing blends of Robusta and Arabica coffees. At different degrees of roasting, 120 ground coffee blends (0.0–33.0%) were formulated. Spectra were obtained by two different techniques, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and paper spray mass spectrometry (PS-MS). Partial least squares (PLS) models were built individually with the two types of spectra. Nevertheless, better predictions were obtained by low and medium-level data fusion, taking advantage from the synergy between these two data sets. Data fusion models were improved by variable selection, using genetic algorithms (GA) and ordered predictors selection (OPS). The smallest prediction errors were provided by OPS low-level data fusion model. The number of variables used for regression was reduced from 2145 (full spectra) to 230. Model interpretation was performed by assigning some of the selected variables to specific coffee components, such as trigonelline and chlorogenic acids.

Coffee brew intake can prevent the reduction of lens glutathione and ascorbic acid levels in HFD-fed animals.

The lens has high concentrations of glutathione (GSH) and ascorbic acid (AsA) to maintain redox activity and prevent cataract formation, which is the leading cause of visual impairment worldwide. Metabolic syndrome is reported to be linked with a higher risk of age-associated cataract. As it was demonstrated previously that coffee consumption improved high-fat diet (HFD) -induced metabolic symptoms, it was hypothesized that coffee intake could delay the onset of obesity related-cataract; however, the effect of coffee consumption on this type of cataract remains unknown. Four-week-old male C57BL/6JJms SLC mice were divided into two groups and were provided ad libitum access to either a control diet (control groups) or a HFD (HFD groups). The control groups and HFD groups were further divided into three or four subgroups for each experiment. Coffee intake markedly reduced the increase in body weight in a roasting-time and concentration-dependent manner. Coffee consumption also prevented the HFD-induced decrease in the concentration of GSH and AsA, and treatment with pyrocatechol or caffeine also restored the reduction of antioxidant compounds. Plasma cholesterol and triglycerides were significantly higher in HFD groups; however, coffee brew or coffee constituent treatment in the HFD-fed mice group prevented elevation of these levels. Caffeine is a major coffee component and pyrocatechol is generated thought the roasting process. These results revealed that caffeine and pyrocatechol in coffee brew may be the key constituents responsible for preventing the reduction of lens GSH and AsA in HFD-fed animals.

Synergistic neuroprotection by coffee components eicosanoyl-5-hydroxytryptamide and caffeine in models of Parkinson's disease and DLB

Hyperphosphorylated α-synuclein in Lewy bodies and Lewy neurites is a characteristic neuropathological feature of Parkinson's disease (PD) and Dementia with Lewy bodies (DLB). The catalytic subunit of the specific phosphatase, protein phosphatase 2A (PP2A) that dephosphorylates α-synuclein, is hypomethylated in these brains, thereby impeding the assembly of the active trimeric holoenzyme and reducing phosphatase activity. This phosphatase deficiency contributes to the accumulation of hyperphosphorylated α-synuclein, which tends to fibrillize more than unmodified α-synuclein. Eicosanoyl-5-hydroxytryptamide (EHT), a fatty acid derivative of serotonin found in coffee, inhibits the PP2A methylesterase so as to maintain PP2A in a highly active methylated state and mitigates the phenotype of α-synuclein transgenic (SynTg) mice. Considering epidemiologic and experimental evidence suggesting protective effects of caffeine in PD, we sought, in the present study, to test whether there is synergy between EHT and caffeine in models of α-synucleinopathy. Coadministration of these two compounds orally for 6 mo at doses that were individually ineffective in SynTg mice and in a striatal α-synuclein preformed fibril inoculation model resulted in reduced accumulation of phosphorylated α-synuclein, preserved neuronal integrity and function, diminished neuroinflammation, and improved behavioral performance. These indices were associated with increased levels of methylated PP2A in brain tissue. A similar profile of greater PP2A methylation and cytoprotection was found in SH-SY5Y cells cotreated with EHT and caffeine, but not with each compound alone. These findings suggest that these two components of coffee have synergistic effects in protecting the brain against α-synuclein-mediated toxicity through maintenance of PP2A in an active state.

In vivo protein expression changes in mouse livers treated with dialyzed coffee extract as determined by IP-HPLC

BackgroundCoffee extract has been investigated by many authors, and many minor components of coffee are known, such as polyphenols, diterpenes (kahweol and cafestol), melanoidins, and trigonelline, to have anti-inflammatory, anti-oxidant, anti-angiogenic, anticancer, chemoprotective, and hepatoprotective effects. Therefore, it is necessary to know its pharmacological effect on hepatocytes which show the most active cellular regeneration in body.MethodsIn order to determine whether coffee extract has a beneficial effect on the liver, 20 C57BL/6J mice were intraperitoneally injected once with dialyzed coffee extract (DCE)-2.5 (equivalent to 2.5 cups of coffee a day in man), DCE-5, or DCE-10, or normal saline (control), and then followed by histological observation and IP-HPLC (immunoprecipitation high performance liquid chromatography) over 24 h.ResultsMice treated with DCE-2.5 or DCE-5 showed markedly hypertrophic hepatocytes with eosinophilic cytoplasms, while those treated with DCE-10 showed slightly hypertrophic hepatocytes, which were well aligned in hepatic cords with increased sinusoidal spaces. DCE induced the upregulations of cellular proliferation, growth factor/RAS signaling, cellular protection, p53-mediated apoptosis, angiogenesis, and antioxidant and protection-related proteins, and the downregulations of NFkB signaling proteins, inflammatory proteins, and oncogenic proteins in mouse livers. These protein expression changes induced by DCE were usually limited to the range ± 10%, suggesting murine hepatocytes were safely reactive to DCE within the threshold of physiological homeostasis. DCE-2.5 and DCE-5 induced relatively mild dose-dependent changes in protein expressions for cellular regeneration and de novo angiogenesis as compared with non-treated controls, whereas DCE-10 induced fluctuations in protein expressions.ConclusionThese observations suggested that DCE-2.5 and DCE-5 were safer and more beneficial to murine hepatocytes than DCE-10. It was also found that murine hepatocytes treated with DCE showed mild p53-mediated apoptosis, followed by cellular proliferation and growth devoid of fibrosis signaling (as determined by IP-HPLC), and subsequently progressed to rapid cellular regeneration and wound healing in the absence of any inflammatory reaction based on histologic observations.

Effect of coffee or coffee components on gut microbiome and short-chain fatty acids in a mouse model of metabolic syndrome

We previously showed that male Tsumura Suzuki obese diabetes (TSOD) mice, a spontaneous mouse model of metabolic syndrome, manifested gut dysbiosis and subsequent disruption of the type and quantity of plasma short-chain fatty acids (SCFAs), and daily coffee intake prevented nonalcoholic steatohepatitis in this mouse model. Here, we present a preliminary study on whether coffee and its major components, caffeine and chlorogenic acid, would affect the gut dysbiosis and the disrupted plasma SCFA profile of TSOD mice, which could lead to improvement in the liver pathology of these mice. Three mice per group were used. Daily intake of coffee or its components for 16 wk prevented liver lobular inflammation without improving obesity in TSOD mice. Coffee and its components did not repair the altered levels of Gram-positive and Gram-negative bacteria and an increased abundance of Firmicutes in TSOD mice but rather caused additional changes in bacteria in six genera. However, caffeine and chlorogenic acid partially improved the disrupted plasma SCFA profile in TSOD mice, although coffee had no effects. Whether these alterations in the gut microbiome and the plasma SCFA profile might affect the liver pathology of TSOD mice may deserve further investigation.

ANAPHYLAXIS TO COFFEE FROM A SPECIFIC GEOGRAPHIC REGION

Introduction We present anaphylaxis to coffee from one region with tolerance to coffee from elsewhere. This is relevant, as foods from various geographic regions are widely available. Case Description 28-year old Saudi Arabian male presented with throat closing, chest tightness, wheezing with airborne exposure to Arabic coffee. When drinking Arabic coffee, he has immediate lip swelling. Denies hives, pruritis, breathing issues. Drinks black Starbucks coffee (House blend, Latin America) without symptoms. Arabic coffee (Yemen) is brewed with cardamom, ginger, milk. Patient tolerates cardamom, ginger, dairy. He has nasal allergies triggered by cats, trees (skin testing, 2016). Significant physical exam findings: dark circles, Dennie's folds, moderate nasal turbinate edema. Skin testing Positive to bell pepper (7/10), walnut (7/10), hazelnut (7/20), brewed Arabic coffee containing cardamom, ginger, milk (13/30). Negative to brewed Starbucks coffee (0/0); cow's milk (0/0). Histamine 7/20 Saline 0/0 Discussion This patient has history consistent with anaphylaxis to Arabic coffee, but not to Latin American coffee. He tolerates the components of Arabic coffee (cardamom, ginger, milk) in other foods. Skin test was positive to brewed Arabic coffee and negative to Latin American coffee. We recommended avoidance of Arabic coffee, self-injectable epinephrine, Albuterol inhaler. To our knowledge, this is the first description of a patient being sensitized to coffee from one region but not another, perhaps due to inherent differences in coffee from disparate regions or to variations in processing. This patient also has tree nut allergy. We were unable to determine whether the Arabic coffee was cross contaminated with any tree nuts.

Phenylindanes in Brewed Coffee Inhibit Amyloid-Beta and Tau Aggregation.

Coffee consumption has been correlated with a decreased risk of developing Alzheimer’s disease (AD) and Parkinson’s disease (PD), but the mechanism by which coffee may provide neuroprotection in humans is not fully understood. We hypothesized that compounds found in brewed coffee may elicit neuroprotective effects by inhibiting the aggregation of amyloid-beta (Aβ) and tau (AD) or α-synuclein (PD). Three instant coffee extracts (light roast, dark roast, decaffeinated dark roast) and six coffee components [caffeine (1), chlorogenic acid (2), quinic acid (3), caffeic acid (4), quercetin (5), and phenylindane (6)] were investigated for their ability to inhibit the fibrillization of Aβ and tau proteins using thioflavin T (ThT) and thioflavin S (ThS) fluorescence assays, respectively. Inhibition of Aβ and α-synuclein oligomerization was assessed using ELISA assays. All instant coffee extracts inhibit fibrillization of Aβ and tau, and promote α-synuclein oligomerization at concentrations above 100 μg/mL. Dark roast coffee extracts are more potent inhibitors of Aβ oligomerization (IC50 ca. 10 μg/mL) than light roast coffee extract (IC50 = 40.3 μg/mL), and pure caffeine (1) has no effect on Aβ, tau or α-synuclein aggregation. Coffee components 2, 4, and 5 inhibit the fibrillization of Aβ at 100 μM concentration, yet only 5 inhibits Aβ oligomerization (IC50 = 10.3 μM). 1–5 have no effect on tau fibrillization. Coffee component 6, however, is a potent inhibitor of both Aβ and tau fibrillization, and also inhibits Aβ oligomerization (IC50 = 42.1 μM). Coffee components 4 and 5 promote the aggregation of α-synuclein at concentrations above 100 μM; no other coffee components affect α-synuclein oligomerization. While the neuroprotective effect of coffee consumption is likely due to a combination of factors, our data suggest that inhibition Aβ and tau aggregation by phenylindane 6 (formed during the roasting of coffee beans, higher quantities found in dark roast coffees) is a plausible mechanism by which coffee may provide neuroprotection. The identification of 6 as a dual-inhibitor of both Aβ and tau aggregation is noteworthy, and to our knowledge this is the first report of the aggregation inhibition activity of 6.

Controlled release of caffeine from tablets of spray-dried casein gels

The controlled release of caffeine from the casein gel tablets has been achieved over release periods lasting from a few minutes to over a few days. A novel casein gel has been acidified at pH of 1.0 as the insoluble controlled-release matrix and spray-dried with coffee for microencapsulation. The optimal inlet temperature of spray drying for the casein-coffee mixtures has been found to be 150 °C. The elastic casein-coffee tablets have been engineered without denaturing the components (as indicated by DSC and FTIR analysis). Pressure-controlled release has been achieved for the casein-coffee tablets prepared by compression at 8 (with lactose excipient), 80 and 160 MPa. The corresponding releases of over 80% caffeine are about 24, 12 and 3–6 h, respectively. By changing the coffee/casein ratio from 10 to 100%, the release time of 80% caffeine can be controlled from 24 to 0.5 h. The spray-dried casein-coffee particles shown in the SEM images are similar in size (about 10 μm) and shape (raisin-like). No significant interactions between the casein and coffee components have been observed by FTIR analysis.

An Insight into the Therapeutic Potential of Major Coffee Components.

The popular drink, coffee (Coffea arabica) is under the great attention of late because of its promising pharmacological potential. Caffeine (the major constituent of coffee) is known for its prominent psychoactive impact. This review aims at highlighting the therapeutic potentials of caffeine and other five coffee components viz. caffeic acid, chlorogenic acids, cafestol, ferulic acid and kahweol and their mechanisms of action. An up-to-date search was made with selected keywords in PubMed, Science Direct, Web of Science, Scopus, The American Chemical Society and miscellaneous databases (e.g., Google Scholar) for the published literature on the selected topic. A number of pharmacological activities are attributed to these components that include anti-oxidant, antiinflammatory, immunomodulatory, anti-microbial, anti-cancer, cardioprotective and neuroprotective effects. In addition, osteogenesis (kahweol), anti-diabetic (caffeine, chlorogenic acid and ferulic acid) and hepatoprotective (chlorogenic acid) activities have also been reported by some of these components in the scientific literature. Caffeine has also been noted for adverse effect on the development of the brain at early stages and reproductive systems. A more advanced pre-clinical and clinical trials are recommended to investigate the safety profiles of these coffee components before their use as possible therapeutics.

Trigonelline mitigates lipopolysaccharide-induced learning and memory impairment in the rat due to its anti-oxidative and anti-inflammatory effect

Brain inflammation is associated with cognitive dysfunction, especially in elderly. Trigonelline is a plant alkaloid and a major component of coffee and fenugreek with anti-diabetic, antioxidant, anti-inflammatory, and neuroprotective effects. In this study, the beneficial effect of trigonelline against lipopolysaccharide (LPS)-induced cognitive decline was assessed in the rat. LPS was injected i.p. at a dose of 500 μg/kg to induce neuroinflammation and trigonelline was administered p.o. at doses of 20, 40, or 80 mg/kg/day 1 h after LPS that continued for one week. Trigonelline-treated LPS-challenged rats showed improved spatial recognition memory in Y maze, discrimination ratio in novel object discrimination test, and retention and recall in passive avoidance paradigm. Additionally, trigonelline lowered hippocampal malondialdehyde (MDA) and acetylcholinesterase (AChE) activity and improved superoxide dismutase (SOD), catalase, and glutathione (GSH). Furthermore, trigonelline depressed hippocampal nuclear factor-kappaB (NF-κB), toll-like receptor 4 (TLR4), and tumor necrosis factor α (TNF α) in LPS-challenged rats. All of the effects of trigonelline followed a dose-dependent pattern and in some aspects, it acted even better than the routinely-used anti-inflammatory drug dexamethasone. Collectively, trigonelline is capable to diminish LPS-induced cognitive decline via suppression of hippocampal oxidative stress and inflammation and appropriate modulation of NF-κB/TLR4 and AChE activity.

An insight towards anticancer potential of major coffee constituents

AbstractCancer is a complex disease that transforms a normal cell into a malignant cell by disturbing different molecular mechanisms. Lately, plant‐derived bioactive products have gained prominent attention to serve as anti‐cancer agents. These natural anti‐neoplastic agents are believed to act as alternatives for the synthetic drugs or could be used to enhance the prospect of other drugs in reducing their dose, thus limiting their possible toxic effects. They could also counterbalance the other anti‐cancer drug‐induced adverse effects. Among natural plant‐derived products, coffee has been reported for its significant anti‐carcinogenic effects in the scientific literature. This article aims to highlight the anti‐cancer potential of different coffee components viz. caffeic acid, chlorogenic acids, caffeine (1,3,7‐trimethylxanthine), cafestol, ferulic acid, and kahweol together in a single article. Based on our article, it is quite clear that these bioactive components have important therapeutic potentials against cancerous cells. However, the lack of clinical data negates their use in humans. Therefore, more research is recommended to achieve the desired pharmaceutical value. We also implore assessing their safety and possible adverse effects prior to their progress into clinical trials. © 2018 BioFactors, 44(4):315–326, 2018

Effect of coffee roasting on in vitro α-glucosidase activity: Inhibition and mechanism of action

In vitro α-glucosidase inhibitory activity of unroasted, and medium, dark and very dark roasted robusta coffee was studied. Coffee extracts significantly inhibited the enzyme activity in a dose-dependent way. The inhibitory activity was well correlated with the degree of roast. Coffee components were separated by gel permeation chromatography into low (1 < MW < 6 kDa), intermediate (15 < MW < 60 kDa) and high (MW > 100 kDa) molecular weight fractions, which were analyzed for the α-glucosidase inhibitory capacity. Only fractions obtained from dark and very dark roasted coffee exhibited inhibitory effect. When the same fraction was obtained from coffee presenting different roasting degree, changes in α-glucosidase inhibition extent were observed. This was attributed to compositional changes within each fraction as induced by roasting. Coffee extracts and their fractions exerted a mixed-type to competitive inhibition against α-glucosidase and these mechanisms are consistent with the complexity of coffee composition.