a shows the number of publications from 1959 to 2016. The number of published articles about P. ginseng
generally increases annually. Since 1959, when German scientist PETKOV W [8
] started to investigate the pharmacology and pharmacodynamics of P. ginseng
, 3974 papers were published until 2016. Based on the number of publications, the past 60 years can be preliminarily divided into three stages, namely, stage I, 1959–1979; stage II, 1980–1999; and stage III, 2000–2016. Stage I (1959–1979) was considered the budding period, when less than 10 papers were published annually. Stage II (1980–1999), also known as the development period, began in 1980, when the number of annual publications reached 10. Stage III (2000–2016) or the boom period is the phase when an increased number of scholars began to focus on P. ginseng
According to publication category (Figure 1
b), the 3974 publications obtained mainly included 3398 formal research articles (85.6%). A total of 262 review articles, 140 proceedings papers, and 103 meeting abstracts accounted for 6.6%, 3.5%, and 2.6% of the publications, respectively. Moreover, 33 notes, 13 letters, 7 corrections, 7 book chapters, 6 editorial materials, and 5 news items comprised less than 1.8% of all the publications.
Based on the heat map of the geographical distribution of research countries (Figure 2
a), Asia, North America, and Europe produced the highest number of publications. P. ginseng
research was conducted in 64 countries. In the first tier, South Korea ranked first in terms of research output by contributing 1632 articles (41.1%), and China ranked second with 1191 publications (27.5%). In the second tier, 396 papers originated from the USA and 381 papers from Japan. In the third tier, India, UK, Canada, and Russia published 127, 109, and 79 papers, respectively.
Burst detection is a computational technique used to identify abrupt changes in events and other types of information [10
]. A burst is detected through two attributes, namely, strength and duration [11
]. The red line segment of the column indicates the time period of burst detections. Figure 2
b shows 15 countries with burst detection during 1959–2016. Of these countries, Japan exhibited the highest strength of 77.84 from 1973 to 2001. Hence, Japan conducted substantial works on P. ginseng
during these years. Scholars from Saudi Arabia started showing interest in ginseng research from 2013 and contributed 13 publications.
As shown in Figure 2
c, the top four countries (South Korea, China, USA, and Japan) with the highest publication number worked in close cooperation with one another. These four countries also worked closely with Canada, Germany, Norway, UK, Australia, Egypt, France, Italy, and India.
lists the top 10 organizations that conducted and provided funds for P. ginseng
research. Of these organizations, eight originated from South Korea and two, namely, Chinese Academy of Sciences and Jilin University, were from China. Similarly, the top 10 sponsor organizations comprised 70% Korean institutions and 30% Chinese institutions (National Natural Science Foundation of China, Ministry of Science and Technology of China, Fundamental Research Funds for the Central Universities). The National Natural Science Foundation of China funded for 263 papers, accounting for almost half of the articles funded by the top 10 sponsor organizations.
shows the cooperation among global research institutions. The thick line indicates high collaboration frequency. A linear partnership was found among Chinese institutions such as Shenyang Pharmaceutical University, Hong Kong Baptist University, Chinese Academy of Medical Sciences, Chinese Academy of Sciences, Changchun University of Chinese Medicine, Jilin University, and Jilin Agricultural University. Numerous Korean institutions presented group cooperation relationship to Jilin Agricultural University from China. Kyung Hee University, Chungbuk National University, Seoul National University, and Konkuk University were in the center position. These Korean institutions cooperated with Zhejiang University and China Pharmaceutical University from China. In Japan, most research institutions exhibited strong cooperation with one another. Five organizations (Russian Academy of Sciences, Toyama Medicinal and Pharmaceutical University, Chongqing Pharmaceutical University, Kyushu University, and Northumbria University) conducted P. ginseng
research individually rather than cooperating with other institutions.
a shows the publication outputs of top 10 authors and their total local citation scores. The top 10 authors originated from Korean institutions; in particular KIM DH and KIM SH contributed the highest number of publications and had the highest citation rate. Basing on the exponential increase in publication numbers during 2000–2016, we focused on the authors who started to burst from 2000 (Figure 4
b). Twenty authors, including YANG DC, KIM YJ, KIM JH, and KIM SH, who also belong to the top 10 authors, had bursts from different years until 2016. Particularly, the articles of KIM SH showed high citation rate. In addition, Yuan CS, Wu JA, and Attele AS from University of Chicago had the highest citation rate and published 29, 7, and 3 articles, with TLCS of 1115, 765, and 684, respectively.
Each paper indexed by the Web of ScienceTM
Core Collection was assigned with one or more subjects. A total of 120 unique subject categories were found (Figure 5
a). The most common category (presented with the largest circle) is pharmacology and pharmacy, followed by plant science, chemistry, and integrative and complementary medicine. The nodes with thick purple ring have high betweenness centrality, which represents great transformation potential of a scientific contribution, and values tend to identify the boundary spanning potential that could lead to transformative discoveries [10
]. Although engineering, biotechnology and applied microbiology, and toxicology and cell biology occupy a small space, their rings in purple indicate high betweenness centrality.
The subject categories of the included papers were analyzed to determine their burstness (Figure 5
b). Sixteen subject categories were detected with bursts. Multidisciplinary sciences, science and technology, and other topics showed burst from 2014 to 2016.
The major topics in P. ginseng
research are shown in Figure 6
. The visual representation, known as a form tree, was generated using clustering software Carrot based on the 38 clusters of the 3974 publications. The leading topics in P. ginseng
research are cell activity, activity of the ginseng extract, study groups, use of ginseng root, cell investigation, induction of ginseng cells, and treatment of cells.
a shows the major keywords of P. ginseng
research. The top 10 keywords in terms of the frequency of occurrence are: ginsenoside, saponin, ginseng, rat, cell, extract, mice, expression, in vitro, and apoptosis. The purple rings of ginsenoside, saponin, constituent, cell, red ginseng, rat, mice, apoptosis, cancer, and polysaccharide indicate their betweenness centrality, and the red ring indicates burst. This representation reveals the development of P. ginseng
research focus (Figure 2
At a fine-grained level, keywords with burst reveal the new trend in P. ginseng
research. Seventy-seven keywords showed burst. Considering that many articles were published after 2000, we focused on keywords with burst since 2000 (Figure 2
b). The burst of keywords until 2016 are Korean red ginseng, nf kappa b, compound k, metabolite, methyl jasmonate, Alzheimer’s disease, biotransformation, ginsenoside rg1, differentiation, inflammation, and cancer. Inflammation, methyl jasmonate, compound k, metabolite, and Alzheimer’s disease had the strongest burst strengths of over 10.
A total of 3974 papers were found in 999 different journals. Table 2
shows that approximately all of the papers were written in English (98.0%), and the remaining papers were written in 12 different languages, such as Chinese (34), Japanese (16), and Russian (11). A few papers were written in Portuguese, German, Polish, French, Hungarian, Italian, Korean, Spanish, and Turkish.
displays that most of the top 20 highest publishing journals originated from South Korea (4), Germany (3), England (3), the USA (3), and the Netherlands (3).
lists the articles with the highest impact factor. The paper, “Herb-drug interactions,” published in The Lancet
in 2000 had the highest impact factor of over 47. The article, “In vitro flowering of embryoids derived from mature root callus of ginseng
),” published in Nature
on 1980 had an impact factor of over 40.
lists the top 10 references with the most citations from 1959 to 2016. Most of the top 10 cited references are reviews, and half of them were published before 2000.
The number of research on P. ginseng
worldwide showed a high growth between 1959 and 2016 and surged since 2000. Asia, especially South Korea and China, are the most active countries on P. ginseng
research because this herb is mainly distributed in these countries (South Korea, 57.4%; and China, 31.1%). The amounts of P. ginseng
produced in China and South Korea account for more than 55% and 34% of the total world output [1
]. The top 10 organizations funding P. ginseng
research all originate from South Korea and China. Hence, these two countries provide stronger financial support for P. ginseng
research than the other countries. However, Japan greatly contributed to study of P. ginseng
during 1973–2001. Saudi Arabia showed great interest in P. ginseng
research since 2013, and most of the publications from this country are related to ginseng extracts.
The global cooperation pattern of different institutions is as important as the research output. Generally, institutions in South Korea and China have the highest number of publications and closest cooperation worldwide. Institutions from Japan, Russia, and UK exhibit less cooperation with the other countries. The USA belongs to the top publishing country but does not appear in the cooperation network (Figure 3
). This finding suggests that research organizations in the USA are scattered.
Korean scholars conducted numerous studies on P. ginseng and published 41% of the total articles obtained. Korean authors, namely, KIM DH and KIM SH, submitted many publications and had high citations. In particular, KIM SH had burst during 2009–2016 and will become an important scholar in the P. ginseng domain in the near future.
China ranks second in terms of the quantity of publications. However, no institution on China belonged to the top 10 highest publishing journals. China still needs to improve the quality of P. ginseng research. China has abundant resources, a large number of research funding support, and high cooperativeness with other countries and thus exhibits high potential on P. ginseng research.
a displays the main disciplines which are involved in P. ginseng
research. Pharmacology, pharmacy, plant sciences, chemistry, integrative & complementary, biochemistry and molecular biology are the leading disciplines. Chemistry is the core discipline, which connects many other disciplines. Plant sciences are closely linked to integrative & complementary medicine, which have close cooperation with chemistry and medicine. Interestingly, chemistry is a bridge between these important subjects, like pharmacology & pharmacy, chemistry and medicinal. Figure 5
b shows that the interest of scholars gradually changed from basic science to applied science during 1959–2016. Studies on neuroscience and neurology showed strong burst and have been the hotspots since 2000. At the bottom of Figure 5
b, the subject categories of multidisciplinary sciences and science and technology exhibited a period of burst between 2014 and 2016, with burst strengths of over 7.6. This finding reveals a new trend of multidisciplinary disciplines in P. ginseng
research. According to the clustering results of topics, numerous scientists focused on ginseng root, extracts, and cells that including cell activity, induction of ginseng cells and treatment of cells. At a fine-grained level, keywords with high frequency of occurrence indicate hotspots, such as ginsenoside, rat, cell, extract, expression, in vitro, and apoptosis. Inflammation, Alzheimer’s disease, compound k, and metabolite have the strongest burst since 2000. Therefore, these keywords will be the central concern of P. ginseng
research in the near future. By analyzing disciplines, topics and key words, it's not difficult to find that the future study of P. ginseng
may be biased towards clinical research and application, such as clinical neurology, toxicology and polymer science. Ginseng root, extracts (especially ginsenoside) and treatment of inflammation, Alzheimer’s disease would continue to be the research hotspots.