Induction of Apoptosis in Tumor Cells by Natural Phenolic Compounds

Investigation has been conducted to delineate the action of some phenolic compounds of natural origin in fourhuman tumor cell lines: acute myeloblastic leukemia (HL-60), chronic myelogenic leukemia (K-562), breastadenocarcinoma (MCF-7) and cervical epithelial carcinoma (HeLa). In cells grown in appropriate media the phenolicscurcumin, yakuchinone B, resveratrol and capsaicin exhibited growth inhibition as assessed by trypan blue dyeexclusion. It was evident from the results of the MTT reduction assay and [3H]thymidine incorporation into nuclearDNA that the phenolics were cytotoxic and inhibited cell proliferation. Dose response studies indicated curcumin tobe most cytotoxic towards HL-60, K-562 and MCF-7 but did not show much activity in HeLa cells. On the otherhand, yakuchinone B, although less active than curcumin, displayed cytotoxicity towards all four cell lines. Resveratrolwas cytotoxic only in leukemic cells, while capsaicin was marginally cytotoxic. All these phenolics did not elicit anycytotoxic activity as judged by the above parameters towards lymphocytes purified from normal human blood.When cells treated with phenolics were stained with propidium iodide and examined under a fluorescent microscope,characteristic apoptotic features such as chromatin condensation and nuclear fragmentation were observed. Scoringof cells with apoptotic and non-apoptotic features showed positive correlation of apoptotic index with dose of phenolic,and fragmented DNA extracted free of genomic DNA displayed on gel electrophoresis a typical ladder pattern.These phenolics which have human exposure are known cancer chemopreventive agents and their action as inducersof apoptosis in tumor cells suggest their potential use in a strategy for cancer control.     

Systematic evaluation of the antioxidant potential of different parts of Foeniculum vulgare Mill. from Portugal

Fennel (Foeniculum vulgare Mill.) is a widespread perennial umbeliferous (Apiaceae) herb, traditionally used for medicinal purposes and human consumption. It is highly recommended for diabetes, bronchitis and chronic coughs, and for the treatment of kidney stones; some of those chronic diseases are related to the production of radical species involved in the oxidative stress. Therefore, the antioxidant potential of this herb might explain some of their empirical uses in folk medicine. This is the first time that a systematic study on different parts of fennel is performed, in order to understand differences in the antioxidant potential of shoots, leaves, steams, and inflorescences, particularly related to their composition in antioxidant compounds such as vitamins (ascorbic acid and tocopherols) and phenolics. The shoots seems to have the highest radical-scavenging activity and lipid peroxidation inhibition capacity (EC₅₀ values < 1.4 mg/ml), which is in agreement with the highest content in phenolics (65.85 ± 0.74 mg/g) and ascorbic acid (570.89 ± 0.01 μg/g) found in this part. The shoots also revealed high concentration of tocopherols (34.54 ± 1.28 μg/g) and were the only part with flavonoids.     

Decomposing leaf litter: the effect of allochthonous degradation products on the antioxidant fitness and photosynthesis of Vesicularia dubyana

Leaf litter is one of the major input sources of organic carbon and nutrients in freshwater ecosystems. Throughout the degradation and leaching of leaf litter in freshwater bodies, "new born" substances are continuously generated and may aggregate to form humic substances (HS). Although the effect of HS on the stress physiology of aquatic macrophytes has been case of several investigations, the effect of these "new born" compounds (leaf litter breakdown products) on the stress physiology of aquatic plants has not been studied yet. Our results show that leaf litter degradation extracts (LLDEs) from oak, beech, and mixed oak and beech leaves have deleterious effects on the physiology of the aquatic bryophyte Vesicularia dubyana, decreasing photosynthetic activity and enhancing oxidative stress response. These findings suggest that leaf litter degradation extracts may be an important environmental factor influencing community structure within freshwater ecosystems.     

Phenolics in cereals, fruits and vegetables: occurrence, extraction and analysis

Consumption of plant foods, particularly fruits, vegetables and cereal grains is encouraged because they render beneficial health effects. Phenolics and polyphenolics are among the most desirable food bioactives because of their antioxidant activity, brought about by a number of pathways, or due to other mechanisms. The analysis of phenolics and polyphenolics requires their extraction possible purification and structure elucidation. This overview provides a cursory account of the source, extraction and analysis of phenolics in fruits, vegetables and cereals.     

The role of polyphenols in the modulation of sirtuins and other pathways involved in Alzheimer's disease

Alzheimer's disease (AD) is characterised by extracellular amyloid deposits, neurofibrillary tangles, synaptic loss, inflammation and extensive oxidative stress. Polyphenols, which include resveratrol, epigallocatechin gallate and curcumin, have gained considerable interest for their ability to reduce these hallmarks of disease and their potential to slow down cognitive decline. Although their antioxidant and free radical scavenging properties are well established, more recently polyphenols have been shown to produce other important effects including anti-amyloidogenic activity, cell signalling modulation, effects on telomere length and modulation of the sirtuin proteins. Brain accessible polyphenols with multiple effects on pathways involved in neurodegeneration and ageing may therefore prove efficacious in the treatment of age-related diseases such as AD, although the evidence for this so far is limited. This review aims to explore the known effects of polyphenols from various natural and synthetic sources on brain ageing and neurodegeneration, and to examine their multiple mechanisms of action, with an emphasis on the role that the sirtuin pathway may play and the implications this may have for the treatment of AD.     

Recovery of phenolic compounds from spent coffee grounds through optimized extraction processes

The aim of the present study was to compare novel methods and technologies of phenolics extraction from spent coffee grounds, as “green” alternative techniques of the conventional ethanol extraction. Three extraction techniques, ultrasound- and microwave-assisted extraction, along with the use of β-cyclodextrin as a solvent have been studied and optimized as the eco-friendly solutions for the efficient extraction of phenolic compounds from Spent Coffee Grounds (SCG). The investigated factors were temperature (20–60 °C), solvent concentration (0–100% v/v water ethanol, EtOH), amplitude (20–60%), and liquid/solid ratio (5–60 mL/g) for ultrasound-assisted extraction (UAE). In the case of microwave extraction (MAE), the effects of solvent concentration (0–100% v/v), liquid/solid ratio (5–60 mL/g), and power (100–600 Watt) were studied. Ethanol (0–100% v/v) and β-cyclodextrin (β-CD, 1–18.5 mg/mL) were also compared as solvents, under the same range of liquid/solid ratio (5–60 mL/g) and temperatures (20–60 °C). In addition, the effect of the drying method (oven drying and freeze-drying), as well as a defatting pretreatment of SCG, were studied under the optimum conditions of each extraction method. The optimum extraction yield (31.79 ± 0.25 mg GAE/g SCG) was achieved using MAE with a liquid/solid ratio of 60 mL/g, a power level 600 W, and a solvent concentration of 68% v/v EtOH. While the maximum yield (34.43 mg GAE/g SCG) was also obtained by the same method from the freeze-dried sample.     

Color and chemical stability of spray-dried blueberry extract using mesquite gum as wall material

Blueberry is an important source of anthocyanins, which are highly colored substances recognized for their antioxidant activity. One of the drawbacks of using anthocyanins as food colorant is their low stability. The objective of this study was to evaluate the variations found in color and concentration of the compounds (which produce the color) on spray-dried powders, obtained from blueberry extracts with added mesquite gum. Ethanolic blueberry extracts were concentrated until reaching 35% of soluble solids. They were then spray-dried using mesquite gum as an encapsulating agent at 140 and 160 °C of air inlet temperature and 8.5, 9.1 and 9.6 mL/min of feeding rates. The lowest losses in the content of total phenolics, total anthocyanins, and color of the samples were found in samples dried at 140 °C and 9.1 mL/min. The microencapsulates that were stored for 4 weeks at 4 °C in the absence of light presented low degradation of phenolics (10%), anthocyanins (7%) and antioxidant activity (15%). Final color values were L = 39.87, C = 47.83 and H° = 28.59, with a total color difference ΔE = 5.     

Changes in the phenolic contents and composition of Persicaria odorata fresh and dried leaves

Leaves of Persicaria odorata (Polygonum odoratum), known also as Vietnamese coriander are used as a pungent additive to dishes of south-eastern Asian cuisine, where it occurs as a native species. Although the essential oil phytochemistry was exhaustively studied, no detailed research on phenolic composition has been conducted. The aim of this research was to investigate what are the main phenolics in dried and fresh leaves with the focus on flavonoids, phenolic acids, and procyanidins. Methanolic-aqueous extracts were analysed with use of HPLC-DAD-MSⁿ validated analytical method. The main compounds identified were methyl gallate (2), (+)-catechin (5), quercetin 3-O-β-D-glucuronide (25), tetrahydroxyflavonol derivative (28), and kaempferol sulfate (33). Comparisons of contents and profile of phenolics were performed.     

Microwave hydrodiffusion and gravity model with a blend of high and low power microwave firing for improved yield of phenolics and flavonoids from oyster mushroom

Oyster mushrooms are a globally important entity both commercially and therapeutically with immense food value. The work describes a successful application of a unique method of microwave hydrodiffusion and gravity combining optimal mix of high and low power microwave firing for the extraction of phenolics and flavonoids principles from oyster mushroom for the first time. Initial firing of microwaves at higher power level (510 W for 2 min and 340 W for 2 min) was applied followed by sustained microwave firing at 170 W till the completion of the extraction as indicated by physical oozing out of the aqueous extract. Such a combination of microwave firing in microwave hydrodiffusion and gravity (MHG) method (26 min) successfully produced two times more yield of extract with 57.7% ± 2.8 and 82.3% ± 3.7 more content of phenolics and flavonoids, respectively, when compared to 5 h Soxhlet extraction and that too with a better reproducibility. Mapping of individual phenolics/flavonoids were carried out and SEM images were studied for better understanding of the operational aspects. The research aims towards canvassing green technologies as in the near future only those technologies shall survive which are in tandem with environment.