**2.1. Plant materials**

**1. Introduction**

140 Phytochemicals - Source of Antioxidants and Role in Disease Prevention

fertilizers production [4].

crop [7].

Soybean (*Glycine max* (L.) Merr) considered among ancient cultivated crops, it was domesticated in the 11th century BC around Northeast of China. It is one of the most widely grown leguminous crops in the world. Its cultivated area was recorded in 95 countries more than 121 million hectare that produced 335 million tons of dry seeds [1] (FAOSTAT, 2016). Soybean had a wide variability, the USDA alone maintains more than 15 thousand soybean accession grouped into 13 maturity classes including both determinate and indeterminate soybean. Early maturing groups are adapted to short summer growing seasons in North USA and Canada while late maturity groups are adapted to southern or coastal plain counties [2]. Soybean occupies an advanced position among agricultural crops, being the most important source of proteins and vegetable oils [3]. Its seeds provided abundant and high quality protein and oil for human diet and animal feed. Its seeds contain more than 36% protein, 30% carbohydrates in addition to fiber, vitamins, and minerals [3]. It also contains about 20% oil, which makes soybean one of the most important edible oil crops. Soy oil has used as binding additives in manufacturing of papers, inks, paints, varnishes, cosmetics, and plastics. It was used also in production of farming pesticides and pharmaceuticals products [4]. Nowadays, biodiesel utilizing soy oil become a new industrial renewable sources of energy. Additionally, soybean as a nitrogen-fixing legume crop helps in reducing the chemical source of nitrogen

Furthermore, tofu, soy milk, soy sauce, miso, etc., have been developed for human consumption, while soya meal (oil extraction by-product) is used as a nutritious animal feed [5]. Moreover, soybean is now regarded as a model legume crop owing to the availability of genome sequence information [6]. Keeping in mind its vast uses, there is huge number of justifications for crop improvement programs throughout the world. Having 53% global production share of all oilseed crops, USA, China, Brazil, Argentina and India gave soybean much attention in the agricultural production systems. Yield and total production of soybean increased over the last two decades due to genetic improvement of this

In comparison with conventional legume and animal feed sources, soybean is considered one of the cheapest food resources with medicinal properties due to their highest protein content and no cholesterol due to its contents of Genistein, photochemical and isoflavones [8]. It can help in disease fighting due to its pharmacological properties and its phytochemicals constitutes, including antioxidant, estrogenic, antidiabetic, anti-hypercholesterolemic, antihyperlipidemic, anti-obesity, antihypertensive, anticancer, anti-mutagenic, hepatoprotective, anti-osteoporotic, antiviral, bifidogenic, anti-inflammatory, immunomodulatory, neuroprotective, wound healing, antimicrobial, goitrogenic anti-skin aging, anti-photoaging activity and the effects of anti-nutritional factors [3]. A 111 volatile compounds in fermented soybean curds were reported by Chung [9] and an 83 in commercial plain sufu [10]. Messina [11] reported that the presence of isoflavones in soybean is behind the pharmacological attributes of this crop. Chemical composition included Phenolic acids, flavonoids, isoflavones, saponins, phytosterols and sphingolipids were recorded in soybean [12–14]. Due to importance of Twenty-four soybean genotypes were grown in Dirab Agriculture Research Station, King Saud University, Riyadh, Kingdom of Saudi Arabia (24\_25049.200 N 46\_22012.500E) on August, 2014 and were collected from nine countries (Argentina, Australia, China, Egypt, India, Indonesia, USA, and Pakistan). The name and geographical origin of these genotypes are presented in the **Table 1**.
