Global trends and biological activity hotspots of d-limonene in essential oils: a 30-year bibliometric study

This study aims to conduct a comprehensive bibliometric analysis of global research trends and hotspots related to the biological activities of d-limonene, a prominent monoterpene compound found in essential oils, that warrant attention. We performed a bibliometric analysis of 1928 publications sourced from the Web of Science core database, covering the period from 1994 to 2024. Utilizing CiteSpace and VOSviewer software, we analyzed publication trends, collaboration networks among countries, institutions, and authors, and explored the evolution of research themes and current hotspots through keyword analysis. Our findings indicate a rapid increase in research on d-limonene activities since 2017, with China and Brazil leading in publication output. Italy and the USA play central roles within the collaboration network. Notably, a core group of authors has yet to emerge in this field. The biological activities of d-limonene, particularly its antibacterial, antioxidant, anti-inflammatory, and antitumor properties, are widely studied. Recent research hotspots focus on its neuroprotective effects and its potential role in inhibiting antibiotic resistance. The study highlights the growing interest in d-limonene and suggests that its use as an adjuvant to enhance therapeutic efficacy through synergistic interactions with other drugs may represent a significant research direction for the future. This analysis provides valuable insights for researchers and practitioners in pharmacology and related fields, emphasizing the importance of d-limonene in advancing health-related applications.