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The Medicinal Plant Names Index

In October 2011, the Royal Botanic Gardens, Kew, began a new project that seeks to create the first-ever comprehensive reference of medicinal plant names. The Medicinal Plant Names Index (MPNI) will map thousands of plants’ common and scientific names, including synonyms, which Kew says will “raise the standard of medicinal plant research, management, and use through enabling collation of relevant pharmacological, phytochemical, and natural product data irrespective of the plant name or synonym used.”1

Basil (Ocimum basilicum, Lamiaceae), for example, is a widely used medicinal plant that has at least 10 species names, said Alan Paton, PhD, Kew’s assistant herbarium keeper and a member of the MPNI team (oral communication, October 26, 2011). Also, just 19 species of the genus Mentha (Lamiaceae) have more than 3,000 scientific names.2 The existence of multiple names for one plant occurs when plant systematists disagree with the original author’s naming, when scientists are unaware that a particular plant has already been named, or when scientists intentionally change plant names to reflect evolving knowledge of relationships among plant species.2 Increasing the perplexity, these various names are scattered about in different reference books, online databases, and pharmacopeias.

“Black cohosh, some people call it Cimicifuga and some call it Actaea,” said Dr. Paton. “And actually they’re the same thing, but some information is held under Cimicifuga and some is under Actaea. As another example, in the genus Plectranthus—a close relative of basil—only about 20% of information for the most used plants is recorded under the commonly accepted name because people have been recording information for a long time. That causes confusion, because if you want to find information on one plant, you have to know and use all of its names.”

MPNI will connect each medicinal plant’s common names, accepted scientific name(s), and synonyms—creating an interlinked, user-friendly, comprehensive map. So a user searching for Actaea racemosa (black cohosh; Ranunculaceae) will see that A. racemosa is also referred to as the species Cimicifuga racemosa. If this user is a scientist, he or she will now know to use both names when researching black cohosh.

While this naming problem exists for all plants, it is especially important to ensure easy access to all names for commercially used medicinal plants.2 Without this information, problems of accuracy and inclusiveness can arise within the areas of medicinal plant research, trade, conservation, regulations, and usage. With funding from the global charitable foundation Wellcome Trust, Kew is partnering with a variety of organizations that have an interest in the MPNI project, including the UK National Poisons Agency, European Medicine Agency, Medicinal Plant Specialist Group of the International Union for the Conservation of Nature, and World Health Organization.1

“People have come to us asking for help with clarification on medicinal plant names,” said Dr. Paton. The index will help them “navigate the chaos.”

One of Kew’s partners on the MPNI, the European Medicines Agency (EMA), noted that the list will aid the development of an international standard for the identification of medicinal products, including those derived from plants and herbal preparations, which is necessary to ensure the quality and safety of medicines, as well as proper referencing of plant names in regulatory medicinal product information.

“This is of particular importance for the Agency in the context of the implementation of the new pharmacovigilance legislation and the provisions set out in Regulation (EC) 726/2004,” said Sabine Brosch, PhD, of EMA, noting that the regulation requires pharmaceutical companies to provide defined information on medicines electronically to the Agency by July 2, 2012. “This includes herbal medicinal products, which require the unique identification of the plants from which the medicinal products derive. Having a validated, well-maintained plant name reference built by Kew and its partners with the relevant expertise and a global view will save efforts and avoid errors and future incompatibilities in the unique identification of plant names and plant-derived medicinal products” (e-mail, November 1, 2011).

Dr. Brosch noted star anise (Illicium verum, Illiciaceae) as an example. “[I. verum] shows antimicrobial properties, whilst the botanical variety Japanese star anise (I. anisatum, also known as I. religiosum, I. japonicum, shikimmi, and skimmi) is scientifically recognized as highly poisonous.”

Debbie Shaw, PhD, head of Chinese and traditional medicines at the Chinese Medicine Advisory Service (ChiMAS) in London, said that the need for the MPNI was identified during the organization’s ongoing collaborations with Kew. Staff members at ChiMAS, which operates within the Medical Toxicology Information Services of Guy’s and St Thomas’s NHS Foundation Trust, will act as expert advisors to the project and will also be part of the user group.

“MPNI is significant as it will be an authoritative list developed by botanical experts as a resource for healthcare professionals and others involved in healthcare—not as an academic exercise for use by other botanists,” said Dr. Shaw. “Reports of suspected adverse reactions to herbal medicines are of no value if you cannot be certain of the identity of the herb(s) that was used. The herbal medicines used in the UK come from all countries around the world. Each has different naming systems and methods of use. In any herbal enquiry we need a quick and reliable way of checking on the names and synonyms that might have been used. Without this information we can waste time looking for information on the incorrect plant, or adverse events may be associated with an incorrect plant.”

Dr. Shaw noted ginseng as an example, explaining that “ginseng” may refer to American, Chinese, Indian, or Brazilian ginseng (respectively: Panax quinquefolius, Araliaceae; P. ginseng; Withania somnifera, Solanaceae [ashwagandha]; Hebanthe eriantha, Amaranthaceae), “all of which are different species and the latter 2 are completely different genera. If ADRs are incorrectly reported, then ‘safe’ herbs may be labeled as potentially toxic. Making correct links between plant names and identification is the basis for scientific and clinical research; and in any assessment of safety and efficacy.”

Expanding Upon The Plant List

The MPNI comes about 1 year after Kew and Missouri Botanical Garden unveiled The Plant List, which sought to be the authoritative list of all plant names currently used.2 While The Plant List will provide some of the data for the MPNI project, according to Dr. Paton, “There’s room for improvement. It’s something to build on.” Dr. Paton explained that The Plant List was completed quite quickly and left unresolved 25% of plant names, including some medicinal plants. Also, it is very technical, allowing users to search for a plant using only the scientific name (Latin binomial) and not common names or synonyms.

The MPNI will finish many medicinal plant entries left uncompleted in The Plant List, and will also allow users to search for plants using the scientific and common names. And though there are other lists of medicinal plant names, such as the American Herbal Products Association’s Herbs of Commerce 2nd ed., Dr. Paton said that the MPNI will be more extensive. “There are lists around,” he said. “But very often, they’re not fully comprehensive. So we have some of the synonyms but not all of the synonyms. Or we have the common names but not the Latin names. Regulation lists have the same plants under 2 Latin names. There’s no central reference point.”

“It is essential for non-botanist researchers to be able to find out under what other names their species of interest might have been studied in the past,” said Wendy Applequist, PhD, assistant curator at the Missouri Botanical Garden. “If the MPNI serves as a ‘one-stop shop’ for researchers, it will be very useful indeed. I would caution that no such list can or should be treated as entirely authoritative. Definition of species, for example, is much more complex in plants than in animals. There are numerous cases in which one botanist would say that 2 names referred to [2] different species, while another would say that one of those names was a synonym of the other. I can’t imagine how one could represent both views simultaneously in a single cross-linked list, although it may be possible” (e-mail communication, October 31, 2011).

Project Features

The MPNI project began with the hiring of an information technology specialist, a product development officer, and a project manager, and by creating a botanical data-gathering post. First, the team will assemble a user group—one of the project’s most important components—to guide the index’s direction, provide feedback, and ensure that the index is user friendly. This group will be built over the next 6 months and will include an international variety of pharmaceutical companies conducting medicinal plant research, various herbal medicine and supplement regulators, and research institutions like universities and nonprofits. To begin, the MPNI will focus on the herbal medicine markets in Europe, the United States, Australia, China, Thailand, and Japan. So far, about 11 institutions—including GlaxoSmithKline, the School of Chinese Medicine in Hong Kong, Springer Publishing Company, and the World Health Organization Uppsala International Drug Monitoring Centre—have sent Kew letters of support, but the MPNI team has not yet decided on the members of its initial user group.

“We’ll be building a wish list of what users want,” said Dr. Paton. “We expect the sorts of things we’ll be asked for are either common names in key languages, the pharmaceutical names, and the names used in pharmacopeias.”

Team members have decided to begin mapping plants contained in the European, US, and Chinese pharmacopeias because these have significant supporting research and are of public interest, said Dr. Paton. Throughout the project’s 3 1/2 years, they’ll expand the index based on which plants and information the user group expresses is important. Dr. Paton noted that the MPNI will probably end up containing names for about 5,000 plants, as well as links to other websites providing helpful and in-depth resources.

Kew is hoping to have its first version of the MPNI online by of the end of 2012. “It will be a little skeletal,” said Dr. Paton, “but it will help to have feedback from users.”

—Lindsay Stafford


  1. Medicinal Plant Name Index (MPNI). Royal Botanic Gardens, Kew website. Available at: Accessed October 26, 2011.
  2. Stafford L. The Plant List: the first comprehensive inventory of most known plant species. HerbalGram. 89:17-18. Available at: