The continuing need for taxonomic input in phytochemical research

Correct taxonomic identification and depositing voucher herbarium specimens in an internationally recognized herbarium institution listed in the Index Herbariorum (https://sweetgum.nybg.org/science/ih/), such as the John G. Searle Herbarium of the Field Museum of Natural History (code: F), Chicago, in our case, are considered critical components and a requirement in phytochemical work. These specimens are not only important as a basis for proper taxonomic identification and as a future reference, but can also decide the fate of a research project. Despite this, numerous aberrations have been observed in the literature over several decades resulting in inconsistencies in the use of the correct plant names in natural products research papers. These include botanical misidentification, the lack of the involvement of a taxonomist when botanical products are purchased, and the lack of documenting the research by depositing herbarium vouchers in a recognized herbarium institution prior to their phytochemical investigation.

This short review attempts to point out the importance of a voucher herbarium specimen as the physical evidence of the correct taxonomic identification of the plant being studied, and the need to have voucher herbarium specimens of plants being investigated deposited in an internationally recognized herbarium institution, so that it may be retrieved whenever needed.

In addition to pointing out common errors found in the use of the correct plant scientific names in natural products research papers, a rationale is presented on the importance of documenting the plant investigated by voucher herbarium specimens and the use of correct taxonomic identification in natural product research papers.

Whether in phytochemistry, food science, drug discovery or other relevant fields, correct botanical identification based on a voucher herbarium specimen is critical for successful research. Examples are presented on the practices of the two senior investigators of this review during their collaborative work for the past several decades, in following appropriate and correct taxonomic protocols in phytochemical research as part of the discovery of bioactive lead compounds as potential candidates for therapies against cancer and other diseases. One example is the case when voucher herbarium specimens dating back >60 years were used in identifying a species of Stevia as a source of the steviol glycoside class of sweeteners. Furthermore, the involvement of a taxonomic specialist in correcting the misidentification of the source plant of the potent rocaglate derivative, silvestrol (18), was shown to be of great value. This has led not only to the use of the correct name of the plant concerned but also enabled further work on the large-scale re-isolation and the more extensive biological testing of the prototype members of this class of antitumor and antiviral secondary metabolites.