Note: An edited extract of mainly the following research papers:
"Review: Nutritional Properties and Benefits of the Date Fruits (Phoenix dactylifera L.)" by Saada M Al-Orf et al.
In book: "Nuts and seeds in health and disease" Chapter 53: Date seeds: Usage of date seed extract in health
"Anti-atherogenic properties of date vs. pomegranate polyphenols: the benefits of the combination"
by Mira Rosenblat, Nina Volkova, Hamutal Borochov-Neori, Sylvie Judeinstein and Michael Aviram, 2015.
Phoenix dactylifera L. is known as the date palm. There are over 600 kinds of dates based on the shape and organoleptic properties (Baliga et al., 2011). In a 2011 paper Al-Fasri notes that dates have medicinal uses including anticancer, antihyperlipidemic, hepatoprotective activities and thereby serving as an essential healthy food in the human diet (Biglari et al., 2009). The date fruit is used in folk medicine to treat the different infectious diseases probably because of their antibacterial ability, immuneomodulatory activity and antifungal property (Baliga et al., 2011). The presence of pharmacological properties could be due to the presence of high concentrations of minerals and a variety of other phytochemicals of diverse chemical structure (Baliga et al., 2011).
Palm date fruits consist of three essential parts: date flesh which constitutes between 85% to 90% of date fruit weight (Amira et al., 2011), date seed or pit which constitutes about 6 to 12% of the total weight of the mature date and skin which is a thin layer surrounding the fruit to protect the fleshy part (El-Sohaimy and Hafez, 2010, Jassim and Naji, 2010 and Shafiei et al., 2010).
Furthermore, aqueous extracts of dates were shown to have potent antioxidant activity, because they inhibit in vitro lipid and protein oxidation and possess free radical scavenging capacity (Vayalil, 2002). Date pits can be used to improve the nutritional value of incorporated food products. Also, extract shows hepatoprotective and antimicrobial activity in rat (Biglari et al., 2009, Jassim and Naji, 2010 and Baliga et al., 2011)."
Moreover, Al-Fasri (Al-Farsi, 2011) writes "that date seeds are a very rich source of dietary fiber; the level varied between 64.5 and 80.15 g/100 g fresh weight. Insoluble dietary fiber (hemicellulose, cellulose, and lignin) is considered to be the major constituent of seed fiber (Al-Farsi & Lee, 2008).
The high nutritional value of date seeds is based on their dietary fiber content, which makes them suitable for the preparation of fiber-based foods and dietary supplements. Dietary fiber has important therapeutic implications for certain conditions, such as diabetes, hyperlipidemia, and obesity, and may have a protective effect against hypertension, coronary heart disease, high cholesterol, colorectal and prostate cancers, and intestinal disorders (Tariq et al., 2000)."
Date seeds are also a rich source of phenolics and antioxidants, which ranged from 3102 to 4430 mg gallic acid equivalent/100 g, and 58,000 and 92900 mmol Trolox equivalent/100 g, respectively. Al-Farsi and Lee (2008) reported the phenolic acids of date seeds; of the nine phenolic acids detected, p-hydroxybenzoic (9.89 mg/100 g), protocatechuic (8.84 mg/100 g), and m-coumaric (8.42 mg/100 g) acids were found to be among the highest. Since the dietary fiber (5.9-8.7 g/100 g), phenolic (172-246 mg gallic acid equivalent/100 g), and antioxidant (14,600-16,200 mmol Trolox equivalent/100 g) contents in date flesh are much lower than in date seeds, date seeds could potentially be utilized as a functional food ingredient (Al-Farsi et al., 2007).
Phenolic compounds of fruit seeds, such as phenolic acids and flavonoids, have been shown to possess many beneficial effects, including antioxidant, anticarcinogenic, antimicrobial, antimutagenic, and anti-inflammatory activities, and the reduction of cardiovascular disease (Shahidi & Naczk, 2004). Thus, it is important to increase the antioxidant intake in the human diet, and one way of achieving this is by enriching food with natural phenolics. As some synthetic antioxidants may exhibit toxicity, have high manufacturing costs, and have lower efficiency than natural antioxidants (Soong & Barlow, 2004).
Date is also a good source of sodium, potassium, magnesium, calcium and iron. A fair amount of chlorine, copper, sulphur and phosphorus exist in date fruit. It also contains at least five vitamins including vitamin C, vitamin B1 (thiamine), B2 (riboflavin) and nicotinic acid (niacin). Enzymes play an important role in the conversion processes that takes place during formation and maturation of the date fruit. Polyphenol oxidase is responsible for biochemical changes of polyphenols to which the tannins belong; they are important in non-oxidative browning reactions of the date (Biglari, 2009).The medicinal use of extracts prepared from plant parts of the dates back to ancient times. Furthermore, it has been proposed that its antioxidant constituents account for its beneficial therapeutic effects (Ljubuncic et al., 2005). Dates have phenolic compounds (mainly cinnamic acids) and flavonoids (flavones, flavonols and flavanones) that provide antioxidant activities (Biglari, 2009). The antioxidant activity of phenolic compounds is a result of their redox properties, which can play an important role in absorbing and neutralizing free radicals, quenching singlet and triplet oxygen, or decomposing peroxides (Farag, 2011). Many of these phytochemicals achieve significant antioxidant capacities that may be associated with lower incidence and lower mortality rates of cancer. Another study concluded that pretreatment with antioxidants inhibited ROS production, protected antioxidant enzymes, and reversed hepatotoxicity (Deng et al., 2012).
Atherosclerosis is a disease of the large arteries; it is the primary cause of heart disease and stroke. Epidemiological studies have revealed that it is the underlying cause of about 50% of all deaths in the world (Lusis, 2002). The decreasing of the concentrations of high-density lipoprotein cholesterol and increasing of low-density lipoprotein cholesterol are the major cause of Coronary heart disease (Baliga et al., 2011).
Studies showed that feeding rats with diet containing defatted date seed flour at 1.5%, 2.5% and at 5.2% concentration caused decreasing in plasma triglycerides, total cholesterol and low density lipoprotein (Al-Maiman, 2005).
Professor Aviram (Aviram et al, 2015) showed that the total polyphenol concentration was 10 times higher. Next, they analyzed the anti-oxidative properties of the above extracts: their ability to scavenge free radicals and to inhibit copper ion induced LDL oxidation.The date seed extract (0–5 μg GAE mL−1) possesses impressive free radical scavenging capacity, as it dose-dependently decreased DPPH absorbance at 517 nm by up to 57%. They then pre-incubated LDL with the above extracts (0–5 μg GAE mL−1), followed by the addition of copper ions. The extent of LDL oxidation was determined by the TBARS assay, and by the lipid peroxides assay. The date extract and the date seed extract significantly decreased the LDL-associated aldehyde (TBARS) levels by up to 47% and 83%, respectively. Similarly, LDL-associated lipid peroxide levels were decreased by up to 76% and 99%, respectively.
Liver diseases are one of a global problem and the major threats to public health, with high endemicity in developing countries (Asha and Pushpangadan, 1998 and Adewusi and Afolayan, 2010). The majority of the hepatotoxic chemicals damage liver cells by inducing lipid peroxidation and other oxidative damages (Recknagel, 1983 and Adewusi and Afolayan, 2010). Liver plays an essential role in transforming and clearing metabolites and xenobiotics, and is susceptible to the toxicity from these agents (Hrvoje et al., 2009).
Several studies assess the ability of date flesh and pits in prevention or treatment of some of the toxic actions of different substances such as carbon tetrachloride (CCl4), thioacetamide (TAA) and dimethoate poisoning on the liver of rats. Which are model for acute viral hepatitis, induced hepatotoxicity, elevation in plasma enzyme and bilirubin concentration and increase significantly serum glucose level (Al-Qarawi et al., 2001, Bruck et al., 2001, Al-Qarawi et al., 2004, Bastway et al., 2008 and Pitsch et al., 2010).
Studies showed that feeding rats with the aqueous extracts of date flesh or pits reduce significantly the levels of the hepatic markers enzymes (alkaline phosphatase, transaminases, gamma-glutamyl transferase and lactate dehydrogenase), hepatic levels of malondialdehyde and concomitantly increased the levels of antioxidant enzymes (Burtis and Ashwood, 2001, and Bastway et al., 2008). In addition, date pit extract shown its ability to restore the normal functional status of the poisoned liver, and protect against subsequent carbon tetrachloride hepatotoxicity on the liver of rats (Al-Qarawi et al., 2004, Jassim and Naji, 2010, and Mohammad and Habibi, 2011). Moreover, Studies confirmed that selenium, ferulic acid, anthocyanin, caffeic acid, quercetin, chlorogenic acids, proanthocyanidins, β-carotene,apigenin and luteolin are the date constituents which have all been reported to acquire hepatoprotective effects against the CCl4-induced hepatic damage in rodents (Lin and Tome, 1988, Al-Qarawi et al., 2004 and Pitsch et al,. 2010).
Free radicals are generated during everyday metabolic processes in a normal cell. Also, generated endogenously (mitochondria, metabolic process, inflammation etc.) or from external sources. Generation of ROS is associated with tissue injury or DNA damage, which are pathological conditions associated with infection, aging, mitochondrial DNA mutations and cancer. Excessive production of ROS or inadequacy in a normal cell’s antioxidant defense system (or both) can cause the cell to experience oxidative stress and the increased ROS may play a role in cellular processes associated with initiation and development of many cancers (Lakshmipathi, et al., 2009).
Saafi et al.,(2011) found that the aqueous date palm fruit extract have protective activity against oxidative damage. It is possible that polyphenolic compounds (flavonoids, anthocyanins and phenolicacids), and trace elements (selenium, copper, zinc andmanganese), in addition to vitamin C present in the date palm fruit are the responsible compounds for this protection. In fact, Vayalil (2002) proved the antioxidant and the antimutagenic activity of the aqueous date palm fruit extract, monitored by the inhibition of lipid peroxidation and protein oxidation and by the aptitude to scavenge superoxide and hydroxyl radicals in vitro.
Other studies by Ishurda and John (2005) have shown that the glucans isolated from the date fruits possess antineoplastic effects in experimental study. They believed that the antitumor activity could be correlated to their structure (1→3)-β-d-glucan linkages. Treatment with the β-glucan containing media caused a dose-dependent increase in apoptosis, which concomitantly decreased the cell viability of the PC-3 cells in vitro (Fullerton et al., 2000).