Trace Elements Measurement In Apricot (Prunus Armeniaca L.) Seeds By Neutron Activation Analysis

Plant food are main sources of elements in human nutrition diet and required for proper growth and body development. Present study involved analyzing the elemental profile attributes of apricot seeds in order to obtain a global pattern of apricot seeds. Trace element in seed of 8 apricot cultivars grown in Syria have been determined using Instrumental Neutron Activation Analysis (INAA). Total of 28 elements namely Potassium (K), Magnesium (Mg), Calcium (Ca), Chlorine (Cl), Sodium (Na), Zinc (Zn), Iron (Fe), Copper (Cu), Aluminum (Al), Manganese (Mn), Rubidium (Rb), Iodine (I), Bromine (Br), Cobalt (Co), Antimony (Sb), Molybdenum (Mo), Chromium (Cr), Mercury (Hg), Barium (Ba), Cadmium (Cd), Cerium (Ce), Lanthanum (La), Selenium (Se), Samarium (Sm), Strontium (Sr), Titanium (Ti), Uranium (U) and Vanadium (V) were determined. The elements present in the apricot seed samples were in the range of levels reported in the literature. The results show that the seed of apricot cultivars grown in Syria is rich in the essential macro and micro-nutrients that are of important in dietary point of view. DOI : 10.14302/issn.2576-6694.jbbs-18-1944 Corresponding Author: Mahfouz Al-Bachir, Syria, Damascus, P.O. Box 6091, Syria, E-mail: ascientific@aec.org.sy Running title: Trace elements in apricot seeds by neutron activation


Introduction
Plants food for human nutrition are the richest source compared to animal ones of many compounds like flavonoids, polyphenoles, polysaccharides, terpenoids, alkaloids, quinones, carotenoids, sterols, glucosinolates and other sulphur-containing compounds essential elements etc. [1,2,3].
Plant foods are main sources of elements in human diet and are required for proper growth and body development [4,5,6]. Elements may be classified from a dietary point of view as essential trace elements (macro or major elements); the possibly essential trace elements (micro elements); and the non-essential trace elements (ultra trace elements) which are toxic and non-toxic elements [5]. The macro-elements are required in amounts greater than 100 mg/dl and the micro-elements are required in amounts less than 100 mg/dl [7]. The ultra trace elements have been found in animals and are believed to be essential for animals [8]. Humans need more than 22 elements; some of them are required in large amounts, but others are required in trace amounts because higher concentrations can be harmful [9]. Required amounts of these elements must be in human diet to purpose a good healthy life [10]. A number of trace elements protect the cell in the tissue from oxidative as these elements are the co-factor of antioxidant enzymes [11,12]. It is known that elements cannot be synthesized by the human body, and can only be obtained from the consumption of certain foods particularly natural and green ones which were recognized, through the utilization of techniques developed for the sensitive detection of trace elements, as important sources of these elements [13].
Trace elements are usually quantified by spectrometric techniques [14,15,16]. Other techniques such as neutron activation analysis (NAA) is also applied to plant samples [17]. The NAA technique is a quantitative and qualitative method of high efficiency for precise determination of about 25-30 elements of different types of samples in ppb or ppm (part per billion or part per million) range [18]. In this technique, the sample is exposed to neutron flow after which radioactive isotopes for interest element are generated.
The radioactive emission and radioactive decay paths for each elements are well known [14]. Previously neutron activation analysis for comparative study of minor and trace elements in cereals [5]. NAA was successfully applied to determine trace and minor element content in medicinal plants [19] and food stuff [20].
There is limited information on the element content of numerous plant foods consumed in some less developed countries, like Syria [8,13]. According to many studies, elements were affected by climate,  [23]. Sweet kernels taste like almond and are usually consumed in Syria as a fresh snack or as an important ingredients in some traditional Syrian meals. Also, the apricot seeds and its oil can be used in the cosmetics, food and drug industry [24,25]. To ensure dependable work, we have adopted the Instrumental Neutron Activation Analysis (INAA) due to its advantages of low detection limit and multi elemental capability. So the objective of this investigation was to evaluate the elemental profile attributes of seeds of eight cultivars of apricot locally grown in Syria using neutron activation analysis (NAA).

Results and Discussion
The NAA analytical technique allowed us to

Overall Essential Major (Macro) Elements Concentrations in Apricot Seed Samples
The element contents in the seed of eight apricot cultivars showed that Potassium (K), Magnesium (Mg), Calcium (Ca), Chlorine (Cl), and Sodium (Na) were established as major elements. Table 1 [4]. Ca is an essential element for human health, participation in the biological functions of several tissues [9]. Ca has been proven clinically associated with reduced risk of various non-communicable diseases [28]. The consumption of crops rich in K is recommended for the prevention of cardiovascular or oncogenic disease [29]. Together with Na this element is involved in regulation of osmotic pressure [8,30]. The Mg is an essential element acts as a Ca antagonist on vascular smooth muscle tone and on post-receptor insulin signaling [31]. In addition, Mg participates with muscle and as a cofactor of up to 300 enzymes [32].
The present study shows that the content of  [33]. The recommended intake for Na is 2400 mg per day [9]. According to United State Department of Agriculture (USDA) the daily recommended intake (RDA) for Na and K intake is not more than 2.400 mg and 4.700 mg respectively per day [9,34]. Low Na concentration and the presence of a great amount of K suggest the use of apricot seeds in an anti-hypertensive diet [35]. K is important for its diuretic nature and Na plays an important role in the transport of metabolites. The ratio of K/Na in any food is an important factor in prevention of hypertension arteriosclerosis, with K depresses and Na enhances blood pressure [36]. In the present study K/Na, also show positive relation.

Overall Essential Micro (trace) Elements Concentrations in Apricot Seed Samples
The overall concentrations of the trace elements in all seed samples of eight apricot cultivars grown in Syria are shown in Tables 2 and 3 Table   3.

Aluminum (Al):
Al is the most widespread metal on the Earth (8% of Earth crust), and nearly all foods contain small amount Al. The daily average intake of Al estimated vary from 2 to 10 mg/day [41]. The range obtained from Al in this study was (13.06 mg/kg) (Baladi cultivar) to (19.81 mg/kg) (Hamwi leqissi). These values are higher than those reported in other research papers for a total of sixteen (16) cereals samples [5]. There is concern because of the possibility of increased amounts of Al being deposited in the brain and implicated as interfering with a variety of cellular and metabolic processes [5].

Manganese (Mn):
The range of Mn in all studied apricot seed samples varies from 10.28 mg/kg (Kullabi cultivar) to 17.46 mg/kg (Wizri cultivar). Mn is a cofactor of hydrolase, decarboxylase, and transferase enzymes [7].
Mn is a component of arginase and superoxide dismutase and plays a role as co-factor of certain enzymes [20,37]. The USDA has recommended an intake of Mn of 2.3 mg/day for adults male and 1.8 mg/day for female [34].

Rubidin (Rb):
The content of Rb in case of apricot seed was Cobalt (Co): The Co content of the studied apricot seeds varied from 0.18 mg/kg (Tadmori cultivar) to 0.67 mg/kg (Ajjami cultivar). The RDA for Co has been defined at around 300 micrograms [6]. Cobalt is required in the haematopoiesis of red blood cells and in preventing anemia [43].
Antimony (Sb):  [42,46]. The content of elements was found to vary widely depending on different cultivars of apricot [27]. The content of trace elements is one of the most essential aspects that influence the use of edible plant parts in human nutrition [30].  [11]. It is well accepted that Cr is essential for normal blood glucose and lipid metabolism and insulin-co adjuvant [32]. Analysis of samples for Mercury (Hg) show that concentration of Hg in all studied seed of apricot cultivars were below detection limit in all the varieties except in Wezri cultivar (0.38 mg/kg). The permissible limit of Hg set by USDA in food was 1.5 mg/kg [47]. Levels of Hg in most field crops are sufficiently low to cause little concern from a human health viewpoint [47]. In this study also we found low levels of Mo, Cr and Hg concentration in apricot seeds of different apricot cultivars were lower than the permissible limits and therefore, do not represent a health risk. Some heavy metals are essential to maintain normal human body functions at trace amount. However, they may be dangerous or even toxic if present at higher concentrations [14]. Keeping in mind the potential toxicity and persistent nature of toxic elements, and the frequent consumption of fruits, it is necessary to analyze these food items to ensure the levels of these contaminants meet agreed international requirements [11]. Different reason may cause contamination of plant products with toxic elements.
Using mineral fertilization, contaminated water, industrial emission and transportation, mining and processing metal ore are the main sources of toxic metal in agricultural system [48].

Conclusion
The NAA analytical technique was used in the elemental analysis in seed of eight apricot cultivars grown in Syria. Concentration of 25 elements were detected. The major and trace elements K, Mg, Ca, Cl, Zn, Fe, Na, Cu, Al, Mn, Rb, I, Br, Co, Sb were detected in all the apricot seed samples (