This section will explore the landscape of Agarwood research, investigate current trends, examines research trends in Agarwood based on the year of publication, identifies authors of the most-cited articles along with their affiliations, delve into the most popular subject areas, rank the top 10 documents by the number of citations, explore the popularity of documents by affiliation, maps the co-authorship network within the Agarwood research community, highlights popular keywords related to the study, and provide a comprehensive network mapping with countries.
4.1. Research trends in Agarwood according to the year of publication
The provided data in Table 3 and Figure 3 offers a comprehensive view of the number of publications over a five-year period. In 2019, there were 75 publications, accounting for 17.05% of the total. The following year, 2020, saw a slight increase to 77 publications, representing 17.50%. Subsequently, 2021 and 2022 exhibited consistency with 98 publications each, constituting 22.27% in both years. The most recent data for 2023 indicates a slight decrease to 92 publications, contributing 20.91% to the total. The percentage distribution reveals that 2021 and 2022 share the highest contribution, each accounting for 22.27%, while 2023, though slightly lower, still maintains a substantial presence with 20.91%. The years 2019 and 2020, with slightly lower percentages, suggest a comparatively smaller contribution during those periods. The analysis indicates a noticeable increase in publications from 2019 to 2020, followed by a plateau in 2021 and 2022, and a slight decrease in 2023. Understanding these trends is crucial for stakeholders, researchers, and policymakers to plan future research strategies, allocate resources effectively, and gain insights into the dynamics of the field over time. Further investigation into the context and factors influencing these trends could provide a more nuanced understanding of the publication landscape.
Table 3 Percentages of research trends in Agarwood
Year
|
Number of Publication
|
Percentage (%)
|
2023
|
92
|
20.91
|
2022
|
98
|
22.27
|
2021
|
98
|
22.27
|
2020
|
77
|
17.50
|
2019
|
75
|
17.05
|
4.2. The most cited articles
The bibliometric analysis of agarwood oil, as reflected in Figure 4 and Table 4 detailing the number of documents published by authors using Scopus Analyzer, offers a comprehensive overview of the scholarly landscape in this field. The data not only highlights prolific authors but also provides a quantitative measure of their individual contributions, expressed as both absolute numbers and percentages. Dai, H.F., emerges as the leading contributor with a substantial 25 documents, representing 2.70% of the total output. His significant percentage indicates a noteworthy influence in the academic discourse surrounding agarwood oil. Following closely is Wang, H., with 24 documents, contributing 2.59% to the overall body of literature. The combined impact of Dai and Wang suggests a concentrated expertise at the forefront of agarwood oil research. Mei, W.L., Ismail, N., and Wei, J., each with 22 and 21 documents, respectively, contribute significantly, with their percentages (2.38% and 2.27%) underscoring their substantial influence. Their work not only adds depth to the field but also indicates a shared prominence in scholarly contributions. Batubara, R., and Li, W., both with 18 documents, represent 1.95% each, contributing meaningfully to the overall body of literature. Their consistent output suggests a sustained commitment to agarwood oil research, contributing to the diversity of perspectives within the academic community. Taib, M.N., Tajuddin, S.N., and Dong, W.H., each with 17 and 16 documents, contribute 1.84% and 1.73%, respectively. While individually their percentages may be slightly lower, their collective impact is crucial in shaping the multidimensional nature of agarwood oil research. The distribution of percentages among these prolific authors not only highlights their individual contributions but also indicates the relative weight of their impact within the broader context of agarwood oil research. This information is valuable for researchers and policymakers seeking to understand the key players in the field, foster collaboration and identify potential areas for further exploration. In conclusion, bibliometric analysis, through both absolute document counts and percentages, provides a nuanced understanding of the scholarly contributions of various authors in the agarwood oil domain. This insight serves as a foundation for identifying research trends, influential figures, and potential collaborative opportunities within this specialized field.
Table 4 Percentage of documents by author
Author Name
|
Number of Document
|
Percentage (%)
|
Dai, H.F.
|
25
|
2.70
|
Wang, H.
|
24
|
2.59
|
Mei, W.L.
|
22
|
2.38
|
Ismail, N.
|
21
|
2.27
|
Wei, J.
|
21
|
2.27
|
Batubara, R.
|
18
|
1.95
|
Li, W.
|
18
|
1.95
|
Taib, M.N.
|
17
|
1.84
|
Tajuddin, S.N.
|
17
|
1.84
|
Dong, W.H.
|
16
|
1.73
|
4.3. The most popular subject area in this research
The bibliometric analysis of documents related to agarwood oil across various subject areas, as presented in Figure 5 utilizing Scopus Analyzer, provides a comprehensive understanding of the multidisciplinary nature of research in this field. The distribution of publications across subject areas not only highlights the diverse facets of agarwood oil exploration but also underscores its significance in a broad spectrum of scientific disciplines.
Agricultural and Biological Sciences emerge as the dominant subject area, with a substantial 178 publications, constituting an impressive 20.97% of the total output. This prominence suggests a strong emphasis on the biological and agricultural aspects of agarwood, potentially exploring its cultivation, biological properties, and ecological impact. The categories of Biochemistry, Genetics, and Molecular Biology closely follow with 145 publications, representing 17.08%. This indicates a substantial focus on the molecular and genetic aspects of agarwood, reflecting a keen interest in understanding the biochemical processes underlying its formation and properties. Chemistry, with 84 publications at 9.89%, signifies a significant contribution to the chemical characterization and analysis of agarwood. The emphasis on chemistry suggests a concentrated effort to unravel the complex chemical composition of agarwood, contributing to its applications and uses. Pharmacology, Toxicology, and Pharmaceutics, with 70 publications (8.24%), reflect a growing interest in understanding the pharmacological properties of agarwood, potentially exploring its applications in medicine and pharmaceuticals. Environmental Science and Medicine contribute significantly, with 68 and 51 publications, representing 8.01% and 6.01%, respectively. This underscores the broader implications of agarwood oil, not only in terms of its ecological impact but also in its potential medicinal applications. Earth and Planetary Sciences, Physics and Astronomy, Engineering, and Computer Science collectively contribute to the interdisciplinary nature of agarwood research, with each subject area accounting for a smaller yet significant percentage of publications.
The diverse distribution of publications across these subject areas highlights the interconnectedness of agarwood oil research with various scientific disciplines. This cross-disciplinary engagement is crucial for comprehensively understanding the various facets of agarwood, from its biological and chemical aspects to its potential applications in medicine and environmental science.
4.4. Top 10 number of citations by research
Table 5 Top 10 number of citations by research
Authors
|
Title
|
Year
|
Source title
|
Cited by
|
Yang et al. (L. Yang et al., 2019)
|
Sesquiterpenoids and 2-(2-phenylethyl)chromones respectively acting as α-glucosidase and tyrosinase inhibitors from agarwood of an Aquilaria plant
|
2019
|
Journal of Enzyme Inhibition and Medicinal Chemistry
|
39
|
Ding et al. (Ding et al., 2020)
|
Genome sequence of the agarwood tree Aquilaria sinensis (Lour.) Spreng: the first chromosome-level draft genome in the Thymelaeceae family
|
2020
|
GigaScience
|
33
|
Lv et al. (Lv et al., 2019)
|
Hydrogen peroxide burst triggers accumulation of jasmonates and salicylic acid inducing sesquiterpene biosynthesis in wounded Aquilaria sinesis
|
2019
|
Journal of Plant Physiology
|
32
|
Sun et al. (Sun et al., 2020)
|
WRKY44 represses expression of the wound-induced sesquiterpene biosynthetic gene ASS1 in Aquilaria sinensis
|
2020
|
Journal of Experimental Botany
|
31
|
Liu et al. (P. Liu et al., 2019)
|
Interxylary phloem and xylem rays are the structural foundation of agarwood resin formation in the stems of Aquilaria sinensis
|
2019
|
Trees - Structure and Function
|
30
|
Thuy et al. (Thuy et al., 2019a)
|
Isolation process and compound identification of agarwood essential oils from Aquilaria crassna cultivated at three different locations in Vietnam
|
2019
|
Processes
|
29
|
Huo et al.(Huo et al., 2019)
|
LC-MS-guided isolation of anti-inflammatory 2-(2-phenylethyl)chromone dimers from Chinese agarwood (Aquilaria sinensis)
|
2019
|
Phytochemistry
|
28
|
Yu et al.(Z. Yu et al., 2020)
|
Anti-inflammatory 5,6,7,8-tetrahydro-2-(2-phenylethyl)chromones from agarwood of Aquilaria sinensis
|
2020
|
Bioorganic Chemistry
|
25
|
Kuo T.-H.; Huang H.-C.; Hsu C.-C. (Kuo et al., 2019)
|
Mass spectrometry imaging guided molecular networking to expedite discovery and structural analysis of agarwood natural products
|
2019
|
Analytica Chimica Acta
|
25
|
Wang et al. (Wang et al., 2022)
|
Identification of a diarylpentanoid-producing polyketide synthase revealing an unusual biosynthetic pathway of 2-(2-phenylethyl)chromones in agarwood
|
2022
|
Nature Communications
|
24
|
The bibliometric analysis of the top 10 most-cited research articles related to Agarwood oil as tabulated in Table 5, as indicated by Scopus Analyzer, sheds light on the seminal contributions that have garnered significant attention within the academic community. These highly cited works span a range of topics, from the chemical composition of agarwood to its molecular biology and medicinal properties. The article by Yang et al. (L. Yang et al., 2019) stands out as the most cited, with 39 citations. The research focuses on sesquiterpenoids and 2-(2-phenylethyl) chromones found in agarwood, showcasing their dual role as α-glucosidase and tyrosinase inhibitors. This work is instrumental in understanding the pharmacological potential of agarwood compounds. Ding et al. (Ding et al., 2020) follow closely with 33 citations, presenting the first chromosome-level draft genome of the agarwood tree Aquilaria sinensis. This groundbreaking genomic study opens avenues for further genetic research and manipulation, providing a valuable resource for the scientific community. Lv at el. (Lv et al., 2019) explore the molecular mechanisms behind agarwood resin formation, earning 32 citations. Their study delves into the hydrogen peroxide burst triggering the accumulation of jasmonates and salicylic acid, elucidating the intricate pathways leading to sesquiterpene biosynthesis. Investigateing the role of WRKY44 in repressing the expression of the wound-induced sesquiterpene biosynthetic gene ASS1 in Aquilaria sinensis was studied by Sun at el. (Sun et al., 2020). This research, with 31 citations, contributes to the understanding of gene regulation in agarwood formation. Next, Liu et al (P. Liu et al., 2019) provide structural insights into agarwood resin formation, specifically focusing on the interxylary phloem and xylem rays. This anatomical study, with 30 citations, establishes the structural foundation for resin production in the stems of Aquilaria sinensis.
Thuy et al. contribute to the exploration of agarwood essential oils, earning 29 citations for their work on the isolation process and compound identification from Aquilaria crassna cultivated in Vietnam (Thuy et al., 2019a). Other notable works include studies on anti-inflammatory compounds isolated from agarwood, such as 2-(2-phenylethyl)chromone dimers (Huo et al., 2019), 5,6,7,8-tetrahydro-2-(2-phenylethyl)chromones (Z. Yu et al., 2020), and the identification of diarylpentanoid-producing polyketide synthase (Wang et al., 2022). Additionally, mass spectrometry imaging is explored as a tool for the discovery and structural analysis of agarwood natural products (Kuo et al., 2019), highlighting the importance of advanced analytical techniques in agarwood research.
These highly cited articles collectively contribute to the growing body of knowledge on agarwood, covering diverse aspects such as its chemical constituents, genomic makeup, pharmacological properties, and applications. The significant citation counts signify the impact and influence of these studies within the scientific community, making them pivotal references in the field of agarwood oil research.
The top 10 affiliations by the number of publications as shown in Figure 6 underscore the global nature of Agarwood research, with prominent representation from institutions in China and Southeast Asia. The Ministry of Education of the People's Republic of China emerges as the leading contributor with 36 publications, showcasing a robust commitment to Agarwood research. Following closely are the Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, and the Chinese Academy of Medical Sciences & Peking Union Medical College with 34 and 33 publications, respectively. These affiliations, both prestigious in the medical sciences domain, demonstrate a sustained interest and investment in understanding the medicinal and therapeutic aspects of Agarwood oil.
Notably, the Chinese Academy of Tropical Agricultural Sciences, with 32 publications, reflects the intersection of agricultural and medical research, emphasizing the multidisciplinary nature of Agarwood studies. This trend is further supported by the presence of Universiti Teknologi MARA, Universiti Malaysia Pahang Al-Sultan Abdullah, and Universitas Sumatera Utara, representing institutions from Malaysia and Indonesia, where Agarwood cultivation and traditional uses have deep cultural roots. The inclusion of Universiti Putra Malaysia, Institut Penyelidikan Perhutanan Malaysia, and Hainan University in the top 10 highlights the diversity of research perspectives. Universiti Putra Malaysia and Institut Penyelidikan Perhutanan Malaysia underscore the role of Malaysian institutions in contributing to the global discourse on Agarwood.
This analysis suggests a collaborative and global effort in Agarwood research, with institutions from China and Southeast Asia playing pivotal roles. The diverse affiliations in the top 10 signify a broad range of expertise, from medicinal plant development to tropical agricultural sciences, contributing to a holistic understanding of Agarwood oil. As the field continues to evolve, these findings provide valuable insights into the collaborative networks and geographic distribution of research efforts, paving the way for future interdisciplinary collaboration and knowledge exchange.
3.6. Top journal publishing work on the subject area
Table 6 shows the results obtained from the Scopus Analyzer and reveals the top journals contributing to the subject area. It presents key information, including the source title, the number of publications, and the respective percentage of contribution. Notably, the IOP Conference Series Earth and Environmental Science emerges as a prominent contributor with 30 publications, constituting 6.79% of the total. Following closely are journals such as Molecules, AIP Conference Proceedings, and Biodiversitas, each making significant contributions to the field. The list showcases a diverse range of journals, from Fitoterapia to Industrial Crops and Products, indicating the interdisciplinary nature of research on agarwood oil. Additionally, journals like the Journal of Tropical Forest Science and Forests underscore the importance of forestry-related publications in this domain. The findings suggest a varied landscape of scholarly output, with Chemistry of Natural Compounds, Phytochemistry Letters, and other specialized journals contributing significantly. Furthermore, the analysis reveals the international scope of research, with journals like Mitochondrial DNA Part B Resources and the Indonesian Journal of Electrical Engineering and Computer Science making noteworthy contributions. The distribution of publications across different journals emphasizes the collaborative and multidisciplinary nature of agarwood oil research.
Table 6: Top journal publishing work on the subject area
Source Title
|
Number of publications
|
Percentage (%)
|
Iop Conference Series Earth and Environmental Science
|
30
|
6.79
|
Molecules
|
17
|
3.85
|
Aip Conference Proceedings
|
14
|
3.17
|
Biodiversitas
|
14
|
3.17
|
Fitoterapia
|
12
|
2.71
|
Journal Of Tropical Forest Science
|
12
|
2.71
|
Industrial Crops and Products
|
10
|
2.26
|
Forests
|
9
|
2.04
|
Chemistry Of Natural Compounds
|
6
|
1.36
|
Indonesian Journal Of Electrical Engineering And Computer Science
|
6
|
1.36
|
Mitochondrial DNA Part B Resources
|
6
|
1.36
|
Phytochemistry Letters
|
6
|
1.36
|
Journal Of Natural Medicines
|
5
|
1.13
|
Phytochemistry
|
5
|
1.13
|
IAWA Journal
|
4
|
0.90
|
International Journal of Biological Macromolecules
|
4
|
0.90
|
Journal Of Asian Natural Products Research
|
4
|
0.90
|
Journal Of Forestry Research
|
4
|
0.90
|
Natural Product Research
|
4
|
0.90
|
Bioresources
|
3
|
0.68
|
4.7. Top Country Contributed to the Subject Area
The examination of the top countries contributing to the subject area reveals significant patterns, as shown in Figure 7. Table 7 presents crucial data, including the number of publications and the respective percentage contributions from each country or territory. China emerges as the leading contributor with a substantial 163 publications, constituting a remarkable 36.88% of the total output. Following closely are Malaysia and Indonesia, with 101 and 89 publications, respectively, showcasing their robust contributions at 22.85% and 20.14% of the total. This distribution underscores the substantial engagement of Asian countries in agarwood oil research. India, Thailand, and Japan contribute significantly, with 29, 22, and 20 publications, respectively. While India represents 6.56% of the total output, Thailand and Japan contribute 4.98% and 4.52%, respectively. The collaborative efforts of these countries indicate a shared interest and involvement in advancing research in the field. Vietnam, Taiwan, the United States, and South Korea also make noteworthy contributions, each with a distinct percentage share ranging from 2.71% to 1.58%. This global distribution highlights the international collaboration and diverse perspectives in agarwood oil research. The dominance of China, coupled with significant contributions from Malaysia and Indonesia, reflects the concentrated regional interest in this subject area. The varied participation of other countries, including those outside Asia, further emphasizes the global relevance and collaborative nature of research on agarwood oil.
Table 7 Top Country Contributed to the Subject Area
Country/Territory
|
Number of Publication
|
Percentage (%)
|
China
|
163
|
36.88
|
Malaysia
|
101
|
22.85
|
Indonesia
|
89
|
20.14
|
India
|
29
|
6.56
|
Thailand
|
22
|
4.98
|
Japan
|
20
|
4.52
|
Viet Nam
|
12
|
2.71
|
Taiwan
|
11
|
2.49
|
United States
|
8
|
1.81
|
South Korea
|
7
|
1.58
|
4.8. Tthe map of Co-Authorship about Agarwood
The map in Figure 8 shows the relationships between different researchers who have co-authored papers about Agarwood oil. The size of the nodes represents the number of papers that an author has co-authored, and the thickness of the edges between nodes represents the strength of the co-authorship relationship. The central nodes in the map are Yuan, Jing-zhe and Dong, Wen-hua, who have co-authored the most papers about agarwood oil together. They are followed by Gai, Cui-juan, Wang, Hao, and Chen, Huiqin. These researchers have all made significant contributions to the field of agarwood oil research. The map also shows some interesting collaborations between researchers from different countries. For example, Yuan, Jing-Zhe from China has co-authored papers with Dong, Wen-Hua from Taiwan, Wang, Hao from China, and Chen, Huiqin from China. This suggests that there is a strong international collaboration in agarwood oil research.
4.9. The popular keywords related to the study
Figure 7 shows the relationships between different keywords that appear frequently together in papers about agarwood oil. The size of the nodes represents the frequency of the keyword, and the thickness of the edges between nodes represents the strength of the co-occurrence relationship. The central node in the map is "agarwood oil," which is not surprising given that it is the main topic of the paper. The other nodes that are most closely connected to "agarwood oil" include "agarwood," "sesquiterpenes," "aquilaria malaccensis," "agarwood essential oil," and "cytotoxicity." These keywords all represent important aspects of agarwood oil, such as its chemical composition, biological properties, and potential uses. The map also shows some interesting relationships between other keywords. For example, "agarwood" is connected to "thymelaeaceae," which is the family of plants that agarwood comes from. "Agarwood essential oil" is connected to "2-(2-phenylethyl) chromone," which is a major component of agarwood essential oil. And "cytotoxicity" is connected to "inflammation," which suggests that agarwood oil may have anti-inflammatory properties. Overall, the network visualization map provides a helpful overview of the main topics that are covered in the literature on agarwood oil. It can also be used to identify new research questions by looking for keywords that are not well-connected to others.
4.10. Network mapping with countries
Figure 8 shows a network map with several countries as nodes and connecting lines between them. The thickness of the lines represents the strength of collaboration between the countries. The countries with the most collaboration are: Malaysia, Thailand, Vietnam, China, and Egypt. These countries are likely the leading producers or researchers of agarwood oil, as they have the most frequent collaborations with other countries on the topic.