A Bibliographic Assessment Using the Degrees of Publication Method: Medicinal Plants from the Rural Greater Mpigi Region (Uganda)

Abstract

In ethnopharmacological research, many field assessment tools exist. Yet, these miss that critical point of how to really determine which species merit the costly lab studies, e.g., evaluation of traditional use via pharmacological assays and isolation of bioactive secondary metabolites. This gap can be filled with the introduction of a new tool for literature assessment: the Degrees of Publication (DoPs). In this study, its application is illustrated through an extensive bibliographic assessment of 16 medicinal plant species that were recently identified in the Greater Mpigi region of Uganda as being frequently used by local traditional healers in the treatment of medical disorders (namely, Albizia coriaria, Cassine buchananii, Combretum molle, Erythrina abyssinica, Ficus saussureana, Harungana madagascariensis, Leucas calostachys, Microgramma lycopodioides, Morella kandtiana, Plectranthus hadiensis, Securidaca longipedunculata, Sesamum calycinum subsp. angustifolium, Solanum aculeastrum, Toddalia asiatica, Warburgia ugandensis, and Zanthoxylum chalybeum). These species are suspected to be understudied, and a thorough bibliographic assessment has not been previously performed. Thus, the objectives of our study were to undertake a comparative assessment of the degree to which each of these plant species has been studied in the past, including evaluation of the quality of the journals where results were published in. The determination of the DoPs enabled successful assessment of the degrees to which each individual plant species has been studied so far, while also taking into account the methodological “research chain of ethnopharmacology” from ethnobotanical studies (“traditional use”) to pharmacological assays (“bioactivity”) and finally to pharmacognostic research (“structure elucidation”). The significance of a research paper was assessed by determining whether its journal and publishing house were members of the Committee on Publication Ethics (COPE). In total, 634 peer-reviewed publications were reviewed covering the period of 1960–2019, 53.3% of which were published in journals and by publishing houses affiliated with COPE (338 publications). The literature assessment resulted in the identification of understudied plants among the selected species. The majority of plants reviewed have not been sufficiently studied; six species were classified as being highly understudied and three more as being understudied: C. buchananii, F. saussureana, L. calostachys, M. lycopodioides, M. kandtiana, and S. calycinum subsp. angustifolium and A. coriaria, P. hadiensis, and S. aculeastrum, respectively. The newly introduced DoPs are a useful tool for the selection of traditionally used species for future laboratory studies, especially for pharmacological bioassays, isolation procedures, and drug discovery strategies.

Intraspecific Variation of Phytochemicals, Antioxidant, and Antibacterial Activities of Different Solvent Extracts of Albizia coriaria Leaves from Some Agroecological Zones of Uganda

“…Despite the widely reported medicinal potential of A. coriaria by ethnobotanical surveys, there are few reports on the phytochemistry and bioactivity of this species [25,36,49]. Classical phytochemical screening of aqueous and organic extracts of A. coriaria stem bark indicated that the active secondary metabolites are saponins, alkaloids, flavonoids, steroids, triterpenoids, reducing sugars, flavone aglycones, volatile oils, polyuronides, glucides, sterols, coumarins, and tannins [50][51][52][53][54][55].…”

Pharmacological Assessment of the Antiprotozoal Activity, Cytotoxicity and Genotoxicity of Medicinal Plants Used in the Treatment of Malaria in the Greater Mpigi Region in Uganda

“…The results of this study therefore further add to the scientific basis for their effectiveness in traditional use in the Greater Mpigi region in Uganda as previously described ( Schultz et al, 2020b ). Furthermore, antimalarial activity was studied and verified for the first time for the majority of the species investigated, which was previously determined by the DoP method ( Schultz et al, 2021a ). It needs to be pointed out that only those extracts were selected for antiplasmodial follow-up experiments that acted as hemozoin formation inhibitors in the pre-screen at concentrations of 10 µg/ml or lower.…”

“…Moreover, the n -hexane extract of the leaves (hE005) showed significant quorum quenching activity against the accessory gene regulator ( agr ) system in S. aureus ( Schultz et al, 2020a ). L. calostachys was recently identified using the DoP method as a highly understudied medicinal species that merits further ethnopharmacological and pharmacognostic research in the lab ( Schultz et al, 2021a ). In fact, only three other studies have been published that examine potential bioactive properties of the plant.…”

“…The last of these studies reported low antiplasmodial activity of a chloroform and a methanolic extract against chloroquine-sensitive P. falciparum D6 (IC 50 : 40.2 and 88.4 μg/ml) ( Jeruto et al, 2015 ). The species L. calostachys was recently reviewed more in detail in the discussion sections of two of our recent publications ( Schultz et al, 2021a ; Schultz et al, 2021c ). As far as to the author’s knowledge, there have been no studies published on the identification or isolation of pharmacologically active secondary plant metabolites from L. calostachys to date, highlighting the vital need to further study this interesting medicinal plant.…”

“…When applying the novel Degrees of Publication (DoP) method for identification of species that merit the costly lab studies in ethnopharmacological research, the majority of these 16 species from the Greater Mpigi region were classified as being either highly understudied or understudied ( Schultz et al, 2021a ). Therefore, the present study further investigated the selected species for antimalarial activity and toxicity, contributing to an evaluation of traditional use and to drug discovery.…”