Panax ginseng grows in the mountainous forest area of Northeast China, mainly in the provinces of Jilin, Liaoning and Heilongjiang, and other places of China.

Panax ginseng is a world-famous traditional Chinese medicine. It belongs to the taxonomic family Araliaceae and can be divided into wild Panax ginseng and cultivated Panax ginseng. Generally, Panax ginseng is harvested in autumn ^[1] Tang, Weici, and Gerhard Eisenbrand. "Panax ginseng CA Mey." Chinese drugs of plant origin. Springer, Berlin, Heidelberg, 1992. 711-737.. Panax ginseng, known as ‘the King of Herbs’, is a perennial herb. Wild Panax ginseng, also called ‘mountain ginseng’, grows slowly and is relatively rare. Therefore, cultivated Panax ginseng is the predominant strain on the market because it generally grows faster than wild ginseng. In general, cultivated Panax ginseng is planted in the garden, hence it is called ‘garden ginseng’. The growing environment of Panax ginseng is extremely stringent, and it has high requirements for light, temperature, humidity, and soil pH. Panax ginseng prefers scattered light or diffuse reflected light and is afraid of direct exposure to strong light, so wild ginseng generally grows in the broad-leaved forests with linden trees ^[2] 张国荣, 庞立杰, 董宇. 关于人参栽培可持续发展的思考. 人参研究. 2007;19(4):42-3.. Panax Ginseng is resistant to cold, and a cool environment is suitable for its growth. Panax ginseng is afraid of high temperature and heat, and it is most suitable to grow in an environment of 15℃ to 20℃. When the temperature exceeds 35℃, Panax ginseng’s stems and leaves will be burned, it will stop growing, and even the seedlings may die. However, in winter, Panax ginseng can survive winter safely even at -40℃. Panax ginseng likes water, but it is afraid of waterlogging and is intolerant of drought, so there are strict requirements on soil moisture. The soil moisture suitable for the growth of Panax ginseng is around 40% to 50%. When the soil moisture is higher than 60%, the oxygen content in the soil reduces, and Panax ginseng is prone to the phenomenon of root rot. However, when the soil moisture is less than 30%, Panax ginseng will lose water and dry up, which is not conducive to the expansion and development of the root. The growth of Panax ginseng requires rich humus, and it likes to grow on brown forest soil that is neutral or slightly acidic, with a pH value of between 6.0 and 7.0 ^[3] 沈亮, 徐江, 董林林, 李西文, 陈士林. 人参栽培种植体系及研究策略. 中国中药杂志. 2015;40(17):3367-73..

The taproot of Panax ginseng is fusiform or cylindrical, it is 3cm to 15cm long, and 1cm to 2cm in diameter. The surface is greyish yellow, the upper portion or whole body of the taproot has loose and shallow intermittent thick horizontal lines and obvious longitudinal wrinkles. The lower portion has 2 to 3 lateral roots, with numerous thin and long rootlets which have an unobvious tiny verruca. Rhizome (reed head) is 1cm to 4cm long and 0.3cm to 1.5cm in diameter. It is often twisted and curved, with adventitious roots and loose indented stem scars (reed bowl). The texture is hard, the cross-section is pale yellowish-white, powdery and with cambium rings, the cortex has yellowish-brown spotted resin canal and radial cracks. Panax ginseng has a distinctive odour, and it tastes slightly bitter and has a sweet aftertaste ^[4] 中国药典. 一部[S]. 2020: 8..

China is the first country in the world to start consuming Panax ginseng and has the earliest written records of Panax ginseng. Statistics show that China is also the largest producer of ginseng in the world, accounting for 55.9% of the global production of Panax ginseng ^[5] Baeg IH, So SH. The world ginseng market and the ginseng (Korea). J Ginseng Res 2013; 37: 1-7.. The earliest medicinal book of China, “Shen Nong Ben Cao Jing” (The Divine Farmer’s Classic of Materia Medica), which was written about 2000 years ago, listed Panax ginseng as the top-grade herb. In the Han Dynasty (202 BC- 220 AD), the clinical applications of Panax ginseng were recorded in the book “Wuwei Medical Brief” and “Treatise on Febrile and Miscellaneous Diseases”. 21 prescriptions containing Panax ginseng were recorded in the book “Treatise on Febrile and Miscellaneous Diseases”. The use of Panax ginseng has reached its highest peak during the Tang and Song dynasties. In addition to the descriptions of Panax ginseng in “Xin Xiu Ben Cao” (The Newly Revised Materia Medica, also called Tang Materia Medica), Panax ginseng is widely used in the prescriptions of “Bei Ji Qian Jin Yao Fang” (Essential Prescriptions Worth a Thousand Gold for Emergencies) and “Qian Jin Yi Fang” (Supplement to the Essential Prescriptions Worth a Thousand Gold) written by Sun Simiao, a famous medical expert. Among them, 310 prescriptions use Panax ginseng in “Qian Jin Yi Fang”, while as many as 445 prescriptions use Panax ginseng in “Bei Ji Qian Jin Yao Fang” (Essential Prescriptions Worth a Thousand Gold for Emergencies). In the Tang Dynasty, Master Jian Zhen, who travelled to the eastern parts of Asia, brought the use of Panax ginseng to Japan. “Zheng Lei Ben Cao” (Classified Materia Medica) in Song Dynasty recorded Panax ginseng as: “Mainly for the five Zang Qi (viscera) insufficiency, the five strains and seven impairmentsweak phlegm, vomiting and unable to digest. It is for Cholera and vomiting. It complements the internal viscera and keeps the mind refreshed”. Thus, since ancient times, Panax ginseng has been used as an important tonic. The atlas of Shangdang ginseng depicted in the book was found to be the earliest ginseng image recorded in the world.  In Ming Dynasty, Chinese Physician Li Yanwen, father of Li Shizhen who is a famous medical scholar, comprehensively described the application of Panax ginseng and created the biography of Panax ginseng. On the basis of his father’s work, Li Shizhen compiled 67 prescriptions for the application of Panax ginseng in the “Compendium of Materia Medica”, and summarized that Panax ginseng “Cures all deficiency syndrome in men and women, fever with spontaneous sweating, dizziness with headache, nausea and vomiting, malaria, diarrhoea and chronic dysentery, frequent urination with dribble, disorder of internal organs caused by fatigue, stroke and heatstroke, numbness, haematemesis, haemoptysis and haematochezia, haematuria,  and metrorrhagia, and diseases during the period of prepartum and postpartum”. In addition to single Panax ginseng, the Chinese Pharmacopoeia (2020 edition) also recorded over 80 different proprietary Chinese medicinal prescriptions which contain Panax ginseng as one of the key ingredients, such as Panax ginseng Jianpi pill, Fuzi Lizhong pill, Panax ginseng Yangrong pill, etc.

Panax ginseng is a traditional medicinal herb for tonifying Qi which can effectively strengthen the immune system, anti-ageing, and resist some chronic diseases through anti-oxidation ^[6] Kitts D, Hu C. Efficacy and safety of ginseng[J]. Public health nutrition, 2000, 3(4a): 473-485.. In addition, Panax ginseng also has strong pharmacological effects on cancer, diabetes, cardiovascular system, immune system, and central nervous system. Especially through its anti-stress and antioxidant effects, Panax ginseng plays a protective role on the central nervous system. The rich pharmacological effects of Panax ginseng are reflected in its vast functional components.

1. Polysaccharides

Polysaccharides are the main active components and primary metabolites of Panax ginseng. Panax ginseng polysaccharides can significantly change the composition of intestinal flora, improve diarrhoea caused by antibiotic use and repair intestinal mucosa through the regulation of the intestinal flora ^[7] Li S, Qi Y, Chen L, et al. Effects of Panax ginseng polysaccharides on the gut microbiota in mice with antibiotic-associated diarrhea[J]. International journal of biological macromolecules, 2019, 124: 931-937.. In addition, Panax ginseng polysaccharides have a regulatory effect on the immune system, especially on immune cells ^[8] Lu M, Huang Y, Yang L, et al. In vitro Assessment of Polysaccharides Immunoregulatory Effects on CD3+ CD56+ NKT-like Cells[J]. Annual Research & Review in Biology, 2021: 83-91.. By regulating natural killer cells (NK cells), Panax ginseng polysaccharides actively attack cancer cells, thus playing a therapeutic role in treating cancer ^[9] Sun Y, Guo M, Feng Y, et al. Effect of ginseng polysaccharides on NK cell cytotoxicity in immunosuppressed mice[J]. Experimental and therapeutic medicine, 2016, 12(6): 3773-3777.. Since the human body cannot produce enzymes that directly metabolize polysaccharides, Panax ginseng polysaccharides and their products metabolized through the intestinal flora, such as short-chain fatty acids, can improve the diseases of the nervous system by regulating the immune system, inflammatory response, and oxidative damage ^[10] Wang N, Wang X, He M, et al. Ginseng polysaccharides: A potential neuroprotective agent[J]. Journal of Ginseng Research, 2020..

2. Ginsenosides

Ginsenosides are other major active substances in Panax ginseng besides polysaccharides and are secondary metabolites of Panax ginseng ^[11] Liu S, Zhong J. Phosphate effect on production of ginseng saponin and polysaccharide by cell suspension cultures of Panax ginseng and Panax quinquefolium[J]. Process Biochemistry, 1998, 33(1): 69-74.. The 2020 edition of Chinese Pharmacopoeia regards ginsenoside Rg1, Re and Rb1 as the main detection indexes for Panax ginseng quality control ^[2] 张国荣, 庞立杰, 董宇. 关于人参栽培可持续发展的思考. 人参研究. 2007;19(4):42-3.. At present, more than 48 ginsenosides have been isolated and identified from Panax ginseng. In vivo and in vitro experiments have demonstrated that ginsenoside Rg3 can bind to drug efflux protein (Pgp) on cancer cells, thereby preventing drug excretion and increasing the drug concentration at the tumour sites to promote the effect of the chemotherapy drugs ^[12] Park J D, Rhee D K, Lee Y H. Biological activities and chemistry of saponins from Panax ginseng CA Meyer[J]. Phytochemistry Reviews, 2005, 4(2): 159-175.. In addition, ginsenoside Rg3 can inhibit the formation of tumour angiogenesis, thus affecting tumour growth ^[13] Nakhjavani M, Smith E, Palethorpe H M, et al. Anti-Cancer Effects of an Optimised Combination of Ginsenoside Rg3 Epimers on Triple Negative Breast Cancer Models[J]. Pharmaceuticals, 2021, 14(7): 633.. Moreover, ginsenoside Rd has a good protective effect on acute lung injury caused by endotoxin ^[14] Yang B, Wang R, Ji L, et al. Exploration of The Function of Ginsenoside RD Attenuates Lipopolysaccharide-Induced Lung Injury: A Study of Network Pharmacology and Experimental Validation[J]. Shock (Augusta, Ga.), 2021.. Furthermore, ginsenoside shows an anti-atherosclerosis effect by inhibiting tyrosine kinase activity ^[15] 宿延丽, 宿艳霞, 宿武林. 人参有效成分及其复方研究进展[J]. 人参研究, 2008 (2): 7-11..

In addition, clinical trials have shown that oral administration of 2g of Panax ginseng daily can significantly increase the content of glutathione and its reductase in the serum, indicating that Panax ginseng has an antioxidant effect ^[16] Kim HG, Yoo SR, Park HJ, Lee NH, Shin JW, Sathyanath R, Cho JH, Son CG. Antioxidant effects of Panax ginseng CA Meyer in healthy subjects: a randomized, placebo-controlled clinical trial. Food and Chemical Toxicology. 2011 Sep 1;49(9):2229-35.. Besides, experiments in rats have shown that ginsenoside Re can reduce blood glucose and lipid levels, and it has a protective effect on oxidative stress in the eyes and kidneys of diabetic rats ^[17] Cho WC, Chung WS, Lee SK, Leung AW, Cheng CH, Yue KK. Ginsenoside Re of Panax ginseng possesses significant antioxidant and antihyperlipidemic efficacies in streptozotocin-induced diabetic rats. European journal of pharmacology. 2006 Nov 21;550(1-3):173-9.. Some studies have shown that Panax ginseng extract can improve the ability of learning and memory in brain-damaged animals ^[18] Ru W, Wang D, Xu Y, He X, Sun YE, Qian L, Zhou X, Qin Y. Chemical constituents and bioactivities of Panax ginseng (CA Mey.). Drug Discov Ther 2015; 9: 23-32. PubMed PMID. 2015;25788049.. Ginsenosides become bioactive only after de-glycosylation by intestinal bacteria. The bioactivities of the aglycon protopanaxadiol and protopanaxatriol were the highest. According to the literature, the most significant effect of Panax ginseng is to delay aging, especially to increase the intellectual effect. It was found for the first time that ginsenoside Rg1 can increase hippocampal neurogenesis in vivo and in vitro under physiological and pathological conditions. This is one of the main mechanisms of its many pharmacological effects on the central nervous system. Ginsenoside Rg1 was further shown to improve the learning and memory of normal rats. The nootropic signalling pathway carried out in normal rats showed that the ginsenoside Rg1 induced signalling pathway is similar to the memory formation of mammals, suggesting that Rg1 may have a potential role in improving the intellectual ability of normal people ^[19] Chu SF, Zhang JT. New achievements in ginseng research and its future prospects. Chinese Journal of Integrative Medicine. 2009 Dec;15(6):403-8..

3. Panaxytriol

Besides polysaccharides and ginsenosides, panaxytriol is also an active substance in Panax ginseng. Panaxytriol is a fatty alcohol found in ginseng root extract. Experiments have shown that panaxytriol has effective anti-cancer properties by inducing Phase 2 metabolic enzymes in the liver that metabolize exogenous substances and remove toxic substances. Its unique properties may be of great significance in cancer treatment ^[20] Ng F, Yun H, Lei X, et al. (3R, 9R, 10R)-Panaxytriol: a molecular-based nutraceutical with possible application to cancer prevention and treatment[J]. Tetrahedron letters, 2008, 49(50): 7178-7179..

The processing methods of Panax ginseng recorded in the 2020 edition of The Chinese Pharmacopoeia is ‘Moisten, sliced into thin layers, dried or crushed into powder when used.’ There are four kinds of processing practices applied in Panax ginseng: sun-dried Panax ginseng, red Panax ginseng, sugar Panax ginseng and white dried Panax ginseng ^[21] 张淼, 秦昆明, 李伟东, 等. 人参炮制过程中化学成分变化及机制研究[J]. 中国中药杂志, 2014, 39(19): 3701-3706.. After being harvested and gently washed to remove the soil, sun-dried Panax ginseng is simply processed by cutting off the small roots and dried under the sun.  The difference between red Panax ginseng and sun-dried Panax ginseng is that steaming process is included prior to drying process.  Maltol is formed as a new component in red Panax ginseng, and different steaming processes also have significant effects on the contents of Rb1, Rg1, Rd, Rc, Rh1 and other ginsenosides in red Panax ginseng ^[22] 张颖, et al. "不同蒸制工艺对红参中人参皂苷类成分的影响." 中国实验方剂学杂志 19.21 (2013): 16-20.. Steaming for excessive time or at high temperature will reduce the content of active components in red Panax ginseng, so the quality control of red Panax ginseng processing requires to be strictly monitored. Sugar Panax ginseng is made by soaking Panax ginseng in cane sugar syrup. White and dried Panax ginseng is made by sun drying or other dehydrating methods after removing the skin of fresh Panax ginseng.

Panax ginseng is approved by China Food and Drug Administration as a raw material simultaneously suitable for medicine and food. However, there are certain restrictions on the consumption of Panax ginseng. The daily intake of Panax ginseng should not exceed 3g per person, and it is not recommended for pregnant women, lactating women, and children under the age of 14. Besides, Panax ginseng should not be eaten together with Veratrum nigrum or Trogopterus dung (dung of Trogopterus xanthipes).

A double-blind randomized controlled clinical trial among a group of healthy men and women in South Korea has shown that oral intake of taking Panax ginseng extract, at 1g or 2g per day, is safe and tolerable. No toxic effects were reported after four weeks of observation ^[23] Lee NH, Yoo SR, Kim HG, Cho JH, Son CG. Safety and tolerability of Panax ginseng root extract: a randomized, placebo-controlled, clinical trial in healthy Korean volunteers. The Journal of Alternative and Complementary Medicine. 2012 Nov 1;18(11):1061-9.. The Japanese pharmacopoeia, the British pharmacopoeia, and the United States pharmacopoeia have recorded the regulation of the chemical components and content of ginseng, but they did not mention any safety suggestions on consuming Panax ginseng. In 2009, the 32nd Session of the International Codex Alimentarius Commission (CAC) reviewed and approved the international standard for ‘Panax ginseng food’, which stipulated that cultivated Panax ginseng can be used in food products. In 2012, the Department of Food Safety Standards, Risk Surveillance and Assessment of China approved the cultivated Panax ginseng as a new sourced food ingredient. On the market, more than 60 kinds of food produced from Panax ginseng have been reported, such as Panax ginseng candy, Panax ginseng wine, Panax ginseng preserved foods, Panax ginseng coffee, etc.

Clinical studies of Panax ginseng focus mainly on immune regulation and anti-tumour. Among the 119 published clinical studies on Panax ginseng, 79.5% of them have shown that Panax ginseng has positive effects in regulating immune function, regulating blood glucose and blood lipids, improving fatigue, and improving the quality of life of the cancer patients ^[24] Fan S, Zhang Z, Su H, Xu P, Qi H, Zhao D, Li X. Panax ginseng clinical trials: Current status and future perspectives[J]. Biomed Pharmacother. 2020,132:110832..