Showing papers by "Ayokunle O. Ademosun published in 2012"

Characterization of the antioxidant properties of phenolic extracts from some citrus peels.

Abstract: This study sought to determine the distribution of free and bound phenolics in some Nigerian citrus peels [orange (Citrus sinensis), grapefruit (Citrus paradisii) and shaddock (Citrus maxima)] and characterize the antioxidant properties. The free phenolics were extracted with 80% acetone, while the bound phenolics were extracted from the alkaline and acid hydrolyzed residue with ethyl acetate. Free phenolic extracts had significantly higher (P < 0.05) DPPH* scavenging ability than the bound phenolic extracts, except in orange peels where the bound phenolic extracts had significantly higher (P < 0.05) DPPH* scavenging ability. Bound phenolics from orange peels had the highest ABTS* scavenging ability (6.09 mmol./TEAC g) and ferric reducing antioxidant properties (FRAP) (71.99 mg/GAE 100 g), while bound phenolics from shaddock peels had the least ABTS* scavenging ability (1.35 mmol./TEAC g) and FRAP (2.58 mg/GAE 100 g) . Bound phenolics from grapefruit peels had the highest OH* scavenging ability (EC50 = 3.8 mg/ml), while bound phenolics from shaddock peels had the least (EC50 = 16.1 mg/ml). The phenolics chelated Fe2+ and inhibited malondialdehyde production in rat’s pancreas in a dose-dependent manner. The additive and/or synergistic action of the free and bound phenolics could have contributed to the observed medicinal properties of the peels; therefore, the high antioxidant properties of the free and bound phenolic extracts from orange peels could be harness in the formulation of nutraceuticals and food preservatives.

Inhibition of Acetylcholinesterase Activity and Fe2+-Induced Lipid Peroxidation in Rat Brain In Vitro by Some Citrus Fruit Juices

Abstract: This study sought to characterize the effects of some citrus fruit juices (shaddock [Citrus maxima], grapefruit [Citrus paradisii], lemon [Citrus limoni], orange [Citrus sinensis], and tangerine [Citrus reticulata]) on acetylcholinesterase activity in vitro. The total phenolic content, radical scavenging abilities, and inhibition of Fe2+-induced malondialdehyde (MDA) production in rats brain homogenate in vitro were also assessed. Orange had significantly (P<.05) higher phenolic content than the other juices. The juices scavenged 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radicals in a dose-dependent manner with orange having the highest scavenging ability. Furthermore, the juices inhibited Fe2+-induced MDA production in rat brain homogenate in a dose-dependent manner with shaddock having the highest inhibitory ability. Acetylcholinesterase activity was also inhibited in vitro by the juices in a dose-dependent manner. The inhibition of acetylcholinesterase activity and antioxidant properties of t...

Dietary Anthocyanins: Impact on Colorectal Cancer and Mechanisms of Action

Abstract: Colorectal cancer is the third most common malignancy in males and the second most common in females, with significant variations in the worldwide distribution, and remains among four leading causes of cancer deaths overall, shows global cancer statistics. The highest incident rates are found in economically developed countries, whereas the lowest rates are noted in Africa and South-Central (Jemal et al., 2011). However, striking increase in colorectal cancer incident trends is observed in areas historically at low risk, such as Spain and some Eastern European (the Czech Republic and Slovakia) and Eastern Asian countries (Japan). On the other hand, generally high incident rates over the past several decades are going down in the Unites States (Center et al., 2009). These recent “perturbations” in colorectal cancer trends probably result from a combination of risk factors, including obesity, sedentary lifestyle, increased prevalence of smoking, excessive alcohol consumption and “westernization” in dietary habits a diet rich in red and processed meat and low intake of fruits and vegetables (Center et al., 2009; Chao et al., 2005; Jemal et al., 2011). Decreasing incident and mortality rates are mainly associated with colorectal cancer screening and improved treatment. Prognosis of these patients depends on the stage of the cancer at diagnosis. As the AJCC (American Joint Committee on Cancer) stage increases from stage I to stage IV, the 5-year overall survival rates decrease dramatically, reaching 90% if the disease is detected early when still localized, though just 39% of colorectal cancers are found at this stage. Almost 25% of patients have a metastatic disease at diagnosis, with a 5-year survival of less than 10% (Goldberg et al., 2007). The primary treatment for colorectal cancer is surgical resection. More than two-thirds of patients undergo radical surgery, but 30-50% of patients who present with stage II or III tumors ultimately experience disease recurrence and distant metastases (Rodriguez-Moranta et al., 2006). Although a broader base of treatment options for metastatic colorectal cancer (mCRC) has evolved in recent years, 50 70% of mCRC

Improvement of the nutritive value and antioxidant properties of citrus peels through Saccharomyces cerevisae solid substrate fermentation for utilization in livestock feed

Abstract: Recently, the world production of citrus fruit is about 80 million tones per year; however, citrus fruits have a small edible portion and large amounts of waste such as peels, unlike other fruits. This study sought to integrate citrus peels to nutrient and nutraceutical sources through Saccharomyces cerevisae solid substrate fermentation techniques. Ground peels from orange (Citrus sinensis), grape fruit (Citrus maxima) and shaddock (Citrus maxima) were fermented with pure strain of Saccharomyces cerevisae for 14days, the products obtained were subsequently analyzed for their proximate composition, phytate and total phenol content, and antioxidant activity as typified by their reducing power, DPPH free radical scavenging ability and Fe (II) chelating ability. This study revealed that S. cerevisae fermentation of the peels caused a significant increase (P<0.05) in the protein [unfermented (4.3 – 6.7g/100g), fermented (12.8 – 19.7g/100g)], fat [unfermented (8.4 – 12.6g/100g), fermented (13.6 – 14.8g/100g)], total phenol content [unfermented (1.0 – 2.7mg/g), fermented (3.7 – 5.4mg/g)] and antioxidant activities (reducing power, DPPH free radical scavenging and Fe (II) chelating ability). Conversely, there was a significant (P<0.05) decrease in the carbohydrate [unfermented (65.5 – 73.8g/100g), fermented (57.2 – 64.2g/100g)], crude fibre [unfermented (9.6 – 12.2g/100g), fermented (1.1 – 3.1g/100g)] and phytate [unfermented (310.3 – 394.9mg/100g), fermented (282.1 – 366.7mg/100g)] content. Therefore, cheap, non-pathogenic and aerobic Saccahromyces cerevisae could be used to enhance the nutritive value and antioxidant properties of citrus peels; however, fermented shaddock and orange peels show the highest nutritive and antioxidant potentials, while grape fruit peel showed the least potential. The fermented peels could be a source of nutrient and nutraceuticals for livestock.