Phytochemicals for Cancer Treatment: An Update on Plant-Derived Anti-Cancer Compounds and their Mechanisms of Action.

Cancer remains one of the major causes of morbidity and mortality worldwide. Scientists from different fields are working to devise an efficient treatment strategy in order to reduce the global burden of cancer. Commonly used treatment approaches for cancer treatment include chemotherapy, immunotherapy, photodynamic therapy, radiation, surgery, etc. These treatment procedures have several pitfalls, such as toxicity, limited bioavailability, rapid elimination, poor specificity, and high cost. On the other side, plant-derived anticancer compounds exhibit several advantages and can overcome these shortcomings. Plant-based anticancer compounds are safer, potent, easily available, and comparatively cost-effective. The current review discusses pure plant- based compounds that are used as a therapeutic remedy for anticancer application. The proposed mechanisms of action, through which these compounds inhibit cancer cell growth, tumor growth, angiogenesis, instigate apoptosis, cytotoxicity, mitochondrial membrane degradation, and reduce cell viability as well as cell cycle progression, are also reviewed. These naturally occurring compounds exhibit great therapeutic potential and could be used as candidate drugs in clinical applications.

Color, flavonoids, phenolics and antioxidants of Omani honey.

Our objectives were to analyze and correlate the color, flavonoids, phenolics and antioxidants of 26 honey samples from 6 honey producing regions in the Sultanate of Oman. The Pfund method was used to measure color, aluminum chloride method for flavonoids determination, Folin-Ciocalteu method for phenolic measurement and DPPH assay to determine antioxidants. Sumer honey was the highest among other samples in terms of color, which ranged 129.8-336.2 mm pfund, flavonoids (1613-2890 mg/kg), phenolics (1624-2898 mg/kg) and antioxidants (7.8-48.6 mg/ml). There was a strong correlation between color, flavonoids and phenolics, where it's moderate between these parameters and antioxidants. The Omani honey was rich in color and phenolics compare to other honey and regarded as a good source of antioxidants to the human diet.

Quality evaluation of Omani honey.

This study was intended to evaluate the quality parameters of 58 Apis mellifera honey samples, from different regions in the Sultanate of Oman. Physicochemical analyses were carried out and examined according to the Gulf Standardization Organization (GSO). The results revealed that 64.4% of the samples were failing to meet the GSO standards due to acidity, hydroxyl methyl furfural (HMF), diastase, sucrose, and glucose & fructose. Acidity and HMF were above the limits in 30% and 29% of the failed samples respectively, where diastase and total glucose & fructose were below the limits in 25% and 5% respectively. Sucrose was above the limits in 11% of the failed samples. The unconformity of the analyzed honey samples to GSO standards could be due to stage of harvesting, process and storage conditions. Therefore, it's important to reconsider the whole process of honey production in Oman in order to improve the technology and honey quality.

Nutritional and functional properties of dates: a review.

This review article provides information on the nutritional and functional constituents of dates (Phoenix dactylifera L.) and their seeds from over 80 references. Date flesh is found to be low in fat and protein but rich in sugars, mainly fructose and glucose. It is a high source of energy, as 100 g of flesh can provide an average of 314 kcal. Ten minerals were reported, the major being selenium, copper, potassium, and magnesium. The consumption of 100 g of dates can provide over 15% of the recommended daily allowance from these minerals. Vitamins B-complex and C are the major vitamins in dates. High in dietary fiber (8.0 g/100 g), insoluble dietary fiber was the major fraction of dietary fiber in dates. Dates are a good source of antioxidants, mainly carotenoids and phenolics. Date seeds contain higher protein (5.1 g/100 g) and fat (9.0 g/100 g) as compared to the flesh. It is also high in dietary fiber (73.1 g/100 g), phenolics (3942 mg/100 g) and antioxidants (80400 micromol/100 g). This detailed information on nutritional and health promoting components of dates and their seeds will enhance our knowledge and appreciation for the use of dates in our daily diet and their seeds as a functional food ingredient.

Optimization of phenolics and dietary fibre extraction from date seeds.

This work was conducted to optimise extraction conditions of phenolics and dietary fibre from date seeds. The effects of solvent to sample ratio, temperature, extraction time, number of extractions and solvent type on phenolic extraction efficiency were studied. At two-stage extraction, each stage 1h duration at 45°C with a solvent to sample ratio of 60:1, is considered optimum. Acetone (50%), and butanone were the most efficient solvents for extraction and purification, increasing the yield and phenolic contents of seed concentrate to 18.10 and 36.26g/100g, respectively. The total dietary fibre of seeds (57.87g/100g) increased after water and acetone extractions to 83.50 and 82.17g/100g, respectively. Nine phenolic acids (free and liberated) were detected in seeds with p-hydroxybenzoic (9.89mg/100g), protocatechuic (8.84mg/100g), and m-coumaric (8.42mg/100g) acids found to be among the highest. After extraction and purification, total phenolic acid content increased significantly from 48.64 to 193.83mg/100g. Protocatechuic, caffeic and ferulic acids were the major phenolic acids found in the concentrates. Based on this study, we believe date seed concentrates could potentially be an inexpensive source of natural dietary fibre and antioxidants and possibly used as a functional food ingredient.

Compositional and sensory characteristics of three native sun-dried date (Phoenix dactylifera L.) varieties grown in Oman.

Three native sun-dried date varieties grown in Oman, namely, Fard, Khasab, and Khalas, were examined for their proximate composition, sugars, dietary fiber, minerals, and organic acids as well as sensory characteristics. The study was conducted on sun-dried dates due to their higher consumption compared with fresh dates. All results are expressed as mean value +/- standard deveiation (n = 3) on a fresh weight basis except for sensory analysis. Date varieties were found to be low in fat and protein, but rich in sugars, dietary fiber, and minerals. They were found to be a good source of energy (278-301 kcal/100 g), due to the high sugar content. Total sugar content ranged from 56.1 to 62.2 g/100 g, being lowest in Khasab and highest in Khalas. Total dietary fiber content of dates varied from 6.26 to 8.44 g/100 g, of which 84-94% was insoluble fiber. Twelve minerals were studied in dates, among which the major minerals were potassium, calcium, magnesium, and phosphorus. Date varieties were also found to be an excellent source of selenium (ranging from 0.36 to 0.53 mg/100 g). Six organic acids were positively identified, among which malic acid predominated in all varieties. Differences (p < 0.05) in the contents of dietary fiber, organic acids, and certain minerals were observed among the three date varieties examined. Descriptive sensory analysis showed that among the nine sensory attributes studied, only the attributes color and desirability were rated as being of significantly (p < 0.01) higher intensity in Fard than in Khasab, whereas flesh firmness was lower (p < 0.01). Thus, these results suggest that although all three dates serve as a good source of vital nutrients, the Khalas variety, which is considered as premium quality, had significantly higher contents of sugar and selenium and a significantly higher energy value than the other varieties studied.

Comparison of antioxidant activity, anthocyanins, carotenoids, and phenolics of three native fresh and sun-dried date (Phoenix dactylifera L.) varieties grown in Oman.

Fresh and sun-dried dates of three native varieties from Oman, namely, Fard, Khasab, and Khalas, were examined for their antioxidant activity and total contents of anthocyanins, carotenoids, and phenolics, as well as free and bound phenolic acids. All results are expressed as mean value +/- standard deviation (n = 3) on a fresh weight basis. Fresh date varieties were found to be a good source of antioxidants (11687-20604 micromol of Trolox equiv/g), total contents of anthocyanins (0.24-1.52 mg of cyanidin 3-glucoside equiv/100 g), carotenoids (1.31-3.03 mg/100 g), phenolics (134-280 mg of ferulic acid equiv/100 g), free phenolic acids (2.61-12.27 mg/100 g), and bound phenolic acids (6.84-30.25 mg/100 g). A significant (p < 0.05) amount of antioxidants and carotenoids was lost after sun-drying of dates, whereas the total content of phenolics and free and bound phenolic acids increased significantly (p < 0.05). Anthocyanins were detected only in fresh dates. Date varieties had different levels and patterns of phenolic acids. Four free phenolic acids (protocatechuic acid, vanillic acid, syringic acid, and ferulic acid) and nine bound phenolic acids (gallic acid, protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid, syringic acid, p-coumaric acid, ferulic acid, and o-coumaric acid) were tentatively identified. Of the date varieties studied, Khalas, which is considered to be premium quality, had higher antioxidant activity, total carotenoids, and bound phenolic acids than other varieties. These results suggest that all date varieties serve as a good source of natural antioxidants and could potentially be considered as a functional food or functional food ingredient, although some of their antioxidant constituents are lost during sun-drying.