Ethnobotanical survey of Rinorea dentata (Violaceae) used in South-Western Nigerian ethnomedicine and detection of cyclotides

• Published in: Journal of ethnopharmacology 2016-02, Vol.179, p.83-91
• Main Authors: Attah, Alfred F., Hellinger, Roland, Sonibare, Mubo A., Moody, Jones O., Arrowsmith, Sarah, Wray, Susan, Gruber, Christian W.
• Format: Article
• Language: English
• Subjects: Animals; Animals, Domestic; Anti-Infective Agents - therapeutic use; Antimalarials - therapeutic use; Cyclotides; Cyclotides - chemistry; Ethnopharmacology; Female; Humans; In Vitro Techniques; Medicine, African Traditional; Myometrium - drug effects; Nigeria; Oxytocics - therapeutic use; Phytotherapy; Plant Extracts - therapeutic use; Pregnancy; Rinorea dentata; Surveys and Questionnaires; Uterus - drug effects; Uterus muscle contractility; Veterinary medicine; Violaceae; Violaceae - chemistry
• ISSN: 0378-8741; 1872-7573
• DOI: 10.1016/j.jep.2015.12.038

People living in the tropical rain forest of South-Western Nigeria use Rinorea dentata (P. Beauv.) Kuntze (Violaceae) in ethno-veterinary medicine to facilitate parturition. There are no evidence-based pharmacological investigations for the uterotonic activity of this plant. (i) Collection of data about the ethnopharmacological uses of R. dentata and evaluation of its uses and applications in health care; (ii) determining potential uterotonic effects in vitro, and (iii) chemical characterization of R. dentata, which is a member of the Violaceae family known to express circular cystine-knot peptides, called cyclotides. The ethnopharmacological use of R. dentata in settlement camps within the area J4 of Omo forest has been investigated by semi-structured questionnaires and open interviews. Use index analysis has been performed by seven quantitative statistical models. Respondents’ claim on the beneficial ethno-veterinary application of the plant to aid parturition has been investigated in vitro by myometrial contractility organ bath assays. The bioactive plant extract was screened by chemical derivatization and mass spectrometry-based peptidomics using reversed-phase HPLC fractionation and MALDI-TOF/TOF analysis. Based on the survey analysis, medicinal preparations of R. dentata have been used for anti-microbial and anti-malaria purpose in humans, and for aiding parturition in farm animals. The latter application was mentioned by one out of six respondents who claimed to use this plant for any medicinal purpose. The plant extract exhibited a weak uterotonic effect using organ bath studies. The plant contains cyclotides and the peptide riden A has been identified by de novo amino acid sequencing using mass spectrometry. Few dwellers around the settlement camps of the tropical forest of Omo (Nigeria) use R. dentata for various health problems in traditional veterinary and human medicine. The weak uterotonic effect of the cyclotide-rich extract is in agreement with the low use value index obtained for this plant. Cyclotides have been reported in the genus Rinorea confirming the ubiquitous expression of these stable bioactive plant peptides within the family of Violaceae. Local populations living within settlement camps in Omo tropical rain forest (Ogun state, South-Western Nigeria) use a Violaceae plant species (Rinorea dentata) for several ethnomedicinal purposes in animals and humans. One application of this plant is to aid parturition in farm animals, such a