Curcuma Longa (Medicinal Plant) Research: A Scientometric Assessment of Global Publications Output with Reference to Web of Science

The present study explores the characteristics of publication records for a total duration of twenty years, from 2000 to 2019, in the field of Curcuma longa research. This study has been carried out based on the multidisciplinary bibliographic database available with the Web of Science in Science Citation Index-Expanded (SCIE) and Social Sciences Citation Index (SSCI) and its implications, using the means of scientometrics research techniques. In order to make this analysis a holistic and comprehensive survey of the research trends in the chosen field, the following variables are taken into account: growth rate; global citation scores; distribution of publications by journals, conferences and institutions; favored media of communication; Hirsch index and citation profile of top institutions, countries and authors; contribution of funding agencies; high number of cited papers and characteristics of their bibliographic details. The total number of publication records has been found out to be 6087 during the study period. These 6087 publications have received 171 h-index, 1, 84,715 global citations score and 30.34 average citations. On the whole, 6087 records were published during the study period (2000-2019) in 18 types of documents from 107 countries with 2005 journals, contributed by as many as 20855 authors affiliated to 4879 institutions. These publications were brought out in 18 languages, and they received 1, 56,986 cited references. Majority of the records were in the form of journal articles, reviews, papers in conference proceedings and meeting abstracts, accounting for 97 percent of the total publications. Naturally enough, English happens to be the leading language of 98.8 percent to have accounted for the most number of publications. The four largest contributing countries in the total literature on Curcuma longa during the entire study period are India (24.68 percent), USA (17.7 percent), China (12.2 percent) and Iran (6.09 percent) respectively. The largest institutional contributor of publication records happens to be the Mashhad University of Medical Sciences, Mashhad, Iran with 1.8 percent of the papers to its credit. The most prolific authors to have published more number of research documents during the study period were Sahebkar A (73 papers), Aggarwal BB (67 papers), Nayak S (35 papers) and Kumar A (33 papers). The journal of “Food chemistry” Elsevier ltd tops the list of journals with maximum number of publication records in the field for the given study period with 70 publications, followed by “Journal of Agricultural and Food Chemistry” American Chemical Society (69 papers), “Phytotherapy Research” John Wiley and sons Ltd (63 papers) and “PLOS One” Public Library of Science (59 papers). While the Third World Congress on Medicinal and Aromatic Plants WOCMAP III held in February 2003 at Thailand resulted in the publication of 6 papers, the following three major funding agencies contributed immensely to the research activities in the field: ‘National Natural Science Foundation of China’ with 318papers, United States Department of Health & Human Services, USA with 304 papers and Council of Scientific Industrial Research, India with 99 papers.


Introduction
Turmeric (Curcuma longa Linn) is a medicinal herb belonging to the family of Zingiberaceae, which is widely cultivated in the tropical and subtropical regions, having its origination from India, Indonesia and Southeast Asia (Paramasivam et al. 2009). It is used as spices and also used in traditional medicine for its widespread medicinal properties like anti-microbial, anti-oxidant, anti-inflammatory, anti-cancer, anti-aging and anti-malarial characteristics. These medicinal properties are ascribed to its compound Curcuminoids which consists of curcumin (CUR), Dimethoxy curcumin (DMC) and bisdemethoxy curcumin (BDMC). Among these curcuminoids, curcumin (diferuloylmethane) is the most predominant bioactive compounds with the presents of

Materials and Methods
The required data were collected from Science Citation Index-Expanded (SCIE) and Social Sciences Citation Index (SSCI) using the ''ISI Web of Knowledge'' an international database of the Clarivate Analytics (version 4.10 -Web of Science), in September 2020. For the purposes of analysis, the aforesaid data on global publications in last twenty years (2000-2019) was collected in the form of electronic download. The Basic search was conducted using the keywords "Turmeric" or "Curcuma longa" or "curcumin" using the core collection of this database, and custom year range of time span 2000 to 2019 was chosen for arriving at the data results. Every 500 data was downloaded as a single component with full records, cited references and the plain text. Thus, a total number of 6087 publication records were obtained for the entire study period using this method. The downloaded data was then tabulated and analysed using the Histcite software and MS Excel for getting the relevant information required for analysis and interpretation.
Additionally, abstracts were included within the search range while using the specific keywords, so as to integrate publications relating to this study from the most related records for the special issue on the turmeric. As a pioneering study on this field of research encompassing such a vast time range, the search terms 'turmeric', 'Curcuma longa' and 'curcumin' were used, in order to arrive at a broader picture of the research in this area as much as possible. A more restricted use of the search terms in an earlier version of this study had affected the identification of literature, more particularly in the fields relating to the vital sciences.
Histcite software has been used for analyzing the result after the data was downloaded from the web of Science database. This software provided the result by analyzing few areas and by preparing tables with local citation scores and global citation scores. Total records have been shown through this software, and the analysis was carried out following the result outputs like Records, Authors, Journals, Cited References, Words, Yearly output, Document type, Language, Institution, and Institution with subdivision and Country. The next step of this analysis was carried out using the ''create citation report'' tool of the Web of Knowledge database. The final results have been arrived at using the Total publications, sum of the times cited, Citing Articles, Without self citations, Average citations per item and h-index.

Literature Review
K.K Mueen Ahmed, B. M. Gupta and Ritu  have examined the twenty years (from 1997 to 2016) of global research publications on curcuma longa in the database of Scopus with a total of 5351 publication records with citation impact, growth rate, collaborative share of papers, subject areas, output and citation of authors and organizations. The publication share of first 15 countries was 92.66 percent, while 340 publications received highest citations between 100 and 3869 during this period. Laksham, S et al. (2020) have examined the global level view of Coronavirus publication outputs by retrieving 7381 records for the period extending from 1989 up to March 2020. They have analyzed the annual publication growth, publication share in global, research communication channels pattern and journals' productiveness. Thus this article has concluded by stating that publication output of joint author's was higher when compared to the single author publications, and open access journals published higher than paid journals. Gupta BM, Mueen Ahmed KK and Ritu  have analyzed the publication records of Glycyrrhiza glabra in global using bibliographical database of Scopus for the total period of twenty years. They came up with the following results; average annual growth rate is 10.87 percent and 19.09 citations per year, China and India are the good number of productive countries 19.81 percent and 13.71 percent. 1153 journals published 3352 papers, twenty organizations in global level published 15.08 percent of the papers, 9.16 percent of the authors, and they received citation scores 14.57 percent and 16.62 percent in the study period. This study reveals that, Asian countries excelled in the total number of publication records more than the other countries in Glycyrrhiza glabra research, whereas the quality of research was found to be higher with American and western countries. Konur, O (2011) has studied the scientometric evaluation of the research on the algae and bio-energy for the period of three decades extending from 1980 to 2009 using Web of ISI Web of Knowledge database. He has investigated the most prolific authors, countries, research institutions, journals, subject areas language of publications and most cited papers. The result of this study showed that the algae and bio-energy had developed exponentially in the past three decades.
B. M. Gupta, K. K. Mueen Ahmed (2018) have conducted a scientometric view on 4900 global publication outputs in the field of Azadirachta indica research during 1997 to 2016. He measured to find out that the average annual growth rate stood at 7.61 percent and the citation score grew at the pace of 13.91 percent per paper. The largest share of publication records was found to have emerged from India with 53.49 percent and Agricultural and biological sciences contributed 48.41 percent. 20.65 percent and 8.92 percent of total share by first twenty five global organizations and authors and 43.63 percent of journal publications were shared among by the first 20 most prolific journals during the study period of 1997 to 2016.
Milad Haghania, Michiel C.J. Bliemer et al. (2020) analyse the bibliometric aspects of this studies on a macro level, as well as those addressing Coronaviruses in general. Moreover, through a scoping analysis of the literature on COVID-19, they have identified the main safety-related dimensions that these studies have thus far addressed.
Nirmal Singh (2017) explained the outlines of the growth of scientific literature on Azadirachta indica in the journals applying bibliometric analysis. The distribution of articles in journals was found nearly acceptable to the Bradford's law of scattering making it obvious that there are a few core journals contributing significantly on Azadirachta indica.
Anwar MA depicts that growth of the literature analyzed in this study indicates that research on Phoenix dactylifera L grew very fast from 1971 onward, reached its peak by 1989, and stabilized after that period. It clearly focused on the direction for plant diseases, plant breeding and the quality of augmenting the food and feed. There is a clear focus in research on improving plant breeding, supervision plant diseases, and augmenting the food and feed quality. The literature from medical feature plays more importance on the animal areas rather than the human areas.  1481   19  2018  680  4676  6.88  3322  4.89  29  20  2019  702  2351  3.35  3945  5.62  18  2000-2009  1335  97478  5962  2010-2019  4752  87177  24324  Total  6087  184708   TR-Total Records TCS-Total Citation Scores CPP-Citation Per Records NAPR-Number of Authors per  Records The cumulated literature output in the field of Curcuma longa on the global scenario is 6087for a 20 year period starting from 2000 up to 2019. The yearly output in Curcuma longa research increased from 55 in the year 2001 to 702 publications in 2019 on the global level. The second half of the study period 2010-2019 saw an increased number of publications and authors following the previous trend, but the number of citations became lower compared to the first decade of the twenty-first Century (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009). The number of publications increased 3.6 times, and the number of authors increased 4 times between the beginning and ending years of the total study period. The years 2005 to 2014 witnessed a total gain of more than 50 h-index, while it was lower than 50 in the rest of the study period years. This data reveals that the total number of researchers and their publications have attained a drastic growth in the field of Curcuma Longa research. Yet, the rather decreased number of citations and decline of H-Index below 50 may be indicating an alarming trend in the particular area of research. It is generally expected that more number of authors and research publications would lead to more citations and an increase in H-Index. It appears strange and alarming that citations and H-Index in this field of research.
Of the total global publication output in the field of Curcuma Longa research for the total study period, 4846 (79.6 percent) have appeared in the form of articles, while 659 (10.8 percent) were Reviews, 204 (3.4 percent) were conference papers, 199 publications were abstracts (3.3 percent), 69 were articles in proceedings (1.1 percent), 34 were editorials (0.6 percent), 23 were Letters (0.4 percent), 12 were corrections (0.2 percent), 9 were news items, 8 were article retracted publications, 7 were early access articles, 5 were review book chapters, 4 were article book chapters, 3 were article data papers, 2 were early access reviews, and 1 publication each was book review, retraction and review retracted.  Country-wise, the global publication share of top 15 countries varied widely from as low as 1.28 percent to as high as 24.68 percent during the study period of 2000-2019, with India accounting for the highest publication share of (24.68 %), followed by USA (17.66 %), China (11.24 % share), UK, Thailand, Japan and South Korea (from 2.58 % to 5.52 %), Spain, Canada, Egypt, Germany, Taiwan, Brazil and Iran (from 1.28 % to 6.09 %) between 2000 and 2019.
Among the whole 106 countries which have research publications in Curcuma Longa to their credit, four countries Bosnia, Lithuania, Ukraine and Yemen are yet to start their citation score. Incidentally, these four countries have produced only one paper each, thereby explaining the reason for zero citation to their credit. While 17 countries among the total list received less than 10 citations, 42 countries managed to score more than 100 citations. Notably, 37 of them received citations between 100 and 1000 citations, while four countries USA (66987), India (36899), China (19214) and South Korea (11215) accounted for the highest number of citations during the study period.
Even though USA has only 1075 publication records to get the second position in the rank of topmost prolific countries, it has successfully gained the highest h-index on the global level in 2000-2019 followed by India (90), China (6) 4 and Japan (50). The remaining countries have gained only a low h-index below 50, exemplifying the minimum impact of their research publications on the global scenario.
It is clearly inferred from the above table that India stands out as the most prolific country from where highest number of research publications have originated, closely followed by the United States. Such an interest in this area of research can be explained by the fact that turmeric is widely cultivated and used in India for its medicinal, cooking and ritual purposes on a large scale. Notwithstanding the number of publication records, US top the citation score and H-Index.

TR-Total Records TCS-Total Citation Scores CPP-Citation Per Paper HIh-index CR-Cited Reference CRPP-Cited Reference Per Paper
The number of publication output varied from 73 to 18 among the top twenty most prolific authors listed in the above table in the field of Curcuma longa research during the total study period (2000-2019). These twenty most prolific authors have together contributed 544publication records on the global level, with a share of 2.6 percent research output to their credit. More significantly, these twenty most prolific authors have taken a huge share of 23.9 percent in citations, with a swapping citation score of 22566to their publications from 2000 to 2019. It is further inferred from the above table that these twenty most prolific authors produced 27.2 publications, received 2214.1 citations, attained 15.05 H-Index and received 1817.9 cited reference on the average during the total study period of twenty years. Table 3    A total of 4879 institutions are found to have participated on the global scenario in the field of research on Curcuma longa during the study period of 2000-2019.Out of these total institutions, as many as 4452 institutions contributed one to five papers each to the field during the study period. It is also found that 216 institutions have produced six t ten papers each, 89 institutions came out with eleven to fifteen papers, each, 40 institutions could contribute sixteen to twenty papers each, 21 institutions involved themselves in the publication of twenty one to twenty five papers each, 11 institutions contributed twenty six to thirty records each, 10 institutions have thirty one to thirty five publication records to each of their credit, and 6 institutions came out with forty one to fifty papers each. As a remarkable contribution of exceptional nature, four institutions have contributed from 51 to 107 papers each, as inferred from the analysis of publication records data for the study period.    A conference is usually understood as a summit consisting of a large number of people to talk about thorough issues of relevance and interest. It is a formal meeting of shared interest, naturally one that takes place over one or few days. Any research conference provides a chance to meet the people thinking in one particular area in order to conduct serious discussions and come out with the new theme. In this line, the above table deals with the conferences on Curcuma longa research for the period of twenty years from 2000 to 2019.
Out of the total number of top 100 conferences, 6 conferences led to the publication of four to six papers, ten of them resulted in 3 papers each, 35 of them produced 2 papers each, and the remaining 56 conferences provided one paper each. Among the top 20 conferences, the highest conferences held in the country of USA (6) followed by Indonesia (3) and Laos (2). The countries South Africa, Czech Republic, South Korea, Taiwan, Switzerland, Greece, Tanzania, India and Thailand were found to have held each one conference during this period.
The highest number of publication record (6)   Public or private organizations offering finance support to prepare research work on individual or group of researchers based on the laboratories and produced research papers are termed as 'funding agencies'. Most of the countries in the world have got funding agencies aimed at disseminating research funds to find out solutions to the current problems like medical, agriculture technology issues. A few of the research works especially in the fields of science, technology and engineering are dependent on full funding from such agencies since research works in these fields are more often than not very expensive and no time limit can be stipulated. As shown in the above table, these twenty organizations from different countries of the world have topped the list of funders for research works in the field of Curcuma longa.  Based on the application of the formula of Time Series Analysis, the results have been obtained separately for the years 2025 and 2030. It is predicted that the future trend of growth rate in Turmeric Research Literature output may incline as the present scenario reveals an increasing trend. The assumption is that there is a positive growth level in productivity of Turmeric Research Literatures.  This study has been conducted for a time period of twenty years. Such an extended time period has been stipulated for this study in order to arrive at a holistic picture of the research trends in the particular field. The findings based on such a holistic analysis is intended to help the researchers, both with experienced and in their early career, to get a clear map of research.

Language of Publications
The total records consisting of 6087 publications were authored in 18 different languages, among which English has, quite naturally for the present scenario, emerges to be the predominant language. A swapping 98.8 percent of the records were published in English language, whereas the other 17 languages together have only 1.2 percent of publications to their credit. Next to the English language, 17 papers got published in Portuguese language, followed by eight papers in Indonesian, seven papers each in Japanese and Spanish languages, six papers in German language. Four papers each were published in Chinese and Turkish, Three papers in Polish and two papers each were authored in Korean, Russian and Thai languages. One paper each was published in Czech, French, Hungarian, Italian, Malay and Persian languages.

Usage of Words
The entire corpus of publication records in the chosen field of study for the study period contained 59644 words matching the keyword search. The word Curcumin was found to have been used in 2435 papers, followed by the word 'Turmeric' used in 1302 papers. While the keyword 'Curcuma' was found in 1219 records, 'longa' was found used in 1007 papers. Some medical terms like Cancer (468), antioxidant (258) and curcuminoids (254) were also found to have been used in the publication records.

VoS Viewer
VOS Viewer was developed by Nees Jan Van Eck and Ludo Waltman, Centre for Science and Technology Studies, Leiden University. It will give the picture of network visualization, Overlay visualization and Density visualization. There are three types of maps created based on network data, bibliographic data and text data. The supported file types are Web of Science, Scopus, Dimensions and pubmed. Here we have used bibliographic data files and create map bibliographic coupling of authors, countries and organizations.

Conclusion
This study has been carried out by involving scientometric analysis methods in the field of Curcuma longa research published and indexed in past 20 years from 2000 to 2019. The major outcome of this study is the segregation of publication records for the study period in the chosen field of research in terms of document types, countries, journals, authors and research institutions with highest number of publications, preferred medium of publication, growth ratio during the twenty years of study period, contribution of funding agencies and role of conferences held in this field.
For this research, the software Histcite and VoS viewer were optimally used so as to derive a more complete picture of the research. The Histcite software was utilized for preparing the tables in the order of annual growth of publications, authorship, organizations, journals and measured citations. Likewise, a graphical picture of bibliographic coupling of authors, institutions and countries in networked references was performed through the VoS viewer.
While mapping out the quality of publication records by measuring citations based on local and global index scores, the study has also provided valuable information on citations through the papers on curcuma longa research including total number of citations, average citation score and Hirsch-index. A total of 6807 papers received 1, 84,708 citations and the h-index was found to be at 171 during this study period.
The highest number of research works were published in the year 2019 (702) and the lowest number of publication was (55) recorded in the year 2001. The first fifteen countries contributed the maximum number of publication records (92.92 percent). India became the top most producers of research publications in terms of number (1502), whereas USA published 1075 records and received the highest citation score of 125. The study also found out that first twenty authors contributed 2.6 percent of publications. In terms of authorship pattern, Sahebkar, A from Mashhad University of Medical Sciences published 73 records to his credit with 3212 citations, while Aggarwal BB from University of Texas received the huge number of 21325 citations from 67 publications. The first twenty institutions were found to have contributed 17.81 percent of the total publication records and 21.22 percent of the citations received. 583 authors published 107 records from the institution of Mashhad University of Medical Sciences, Iran.