A survey of biological nitrogen fixation in adzuki beans, soybeans, and mung beans, three legumes in traditional Chinese medicine

The adzuki bean (Vigna angularis) is a traditional legume crop that plays a crucial role in both the sustainability of agricultural systems and the supply of food protein. Having been used for thousands of years in China as traditional Chinese medicine and food, the adzuki bean has a great potential to be a drug candidate or functional food. Adzuki is a good source of essential fatty acids, fiber, minerals, and phytochemicals such as polyphenols and phytates. Legumes are nitrogen-fixing systems that have long been used for biological nitrogen fixation in agriculture. The biologically fixed nitrogen of adzuki beans can reduce the hazards of chemical fertilizers. Because of the increasing requests for plant production, especially protein and oils, and to decrease the economic and environmental pressure on agricultural ecosystems, grain legumes such as adzuki beans are expected to play a major role in future crop systems and sustainable agriculture. Legumes, especially those that have various medicinal effects, can help to restore organic matter to the soil and reduce pests and diseases problems, and they may lead to increased soil fertility. Adzuki beans have considerable potential globally to be a functional food for health promotion and disease prevention not only in Asian countries, but also in other parts of the world. China is the home of the soybean. Traditional Chinese medicine (TCM) is a natural and organic healthcare system in which the body is viewed as a complex network of interconnected parts. The most important health benefits of soybeans are that they improve metabolic activity, promote healthy weight gain, have anticancer potential, boost heart health, relieve menopausal symptoms, boost digestion, improve bone health, prevent birth defects, improve circulation, control diabetes, and relieve sleep disorders. Soybeans can clear heat, detoxify, ease urination, lubricate the lungs and intestine, and serve as an excellent source of protein. In soybeans, atmospheric nitrogen (N2) fixation happens in the nodules, which grow in the roots and are produced by N2-fixing rhizobial bacteria. Most of these bacteria belong to the genera Bradyrhizobium, Mesorhizobium, Rhizobium, and Sinorhizobium. With the world's increasing dependence on agriculture to feed its population, the use of reduced nitrogen derived from energy provided by fossil fuels is not likely to be sustainable. The key to future sustainable agriculture is to utilize the fundamental knowledge of the process of symbiotic nitrogen fixation in association with other agricultural practices to benefits an increasing world population. The food therapy of TCM aims to maintain balanced nutrition through diet. Mung beans, also known as lu dou, are a traditional soy food consumed mainly in East Asia, especially China and Japan. It has been used both as nutritional food and herbal medicine. The two principal properties that make mung beans useful to agriculture are their high protein content and their ability to fix atmospheric nitrogen. The factors determining the symbiotic process are the genetic constitution of the host plant and the bacteria, the environment, and technological inputs such as inocula, fertilizers, and pesticides. As a consequence of the persistent energy crises, which result in higher fertilizer costs, biological N2 fixation has become one of the most attractive strategies for the development of sustainable agricultural systems. Inoculation with Bradyrhizobium enhanced the nodulation, shoot biomass, and grain yield of mung beans. The legume residues can supply more mineral nitrogen to the succeeding crops than cereal residues can, owing to the relatively high nitrogen content of the legume residues. In traditional Chinese medicine, the mung bean clears heat, detoxifies, quenches thirst, promotes urination, reduces swelling, and reduces edema in the lower limbs. It is recommended for edema, conjunctivitis, diabetes, dysentery, summer heat, heatstroke, dehydration, and food poisoning from spoiled food. All in all, the most important health benefits of mung beans are antioxidant effects, antifungal and antimicrobial activity, antiinflammatory activity, and their antidiabetes, antihypertension, and anticancer effects. Mung beans are rich is easily digestible protein. They also contain vitamin A, iron, calcium, zinc, and folate. and are high in vitamins B1, B2, and C and niacin. Their antinutrients are phytic acid, tannins, hemagglutinins, and polyphenols. Nutrition therapy based on TCM is quite effective at treating common diseases.