Mubo A. Sonibare

Cyclotide Discovery in Gentianales Revisited—Identification and Characterization of Cyclic Cystine-Knot Peptides and Their Phylogenetic Distribution in Rubiaceae Plants

Cyclotides are a unique class of ribosomally synthesized cysteine-rich miniproteins characterized by a head-to-tail cyclized backbone and three conserved disulfide-bonds in a knotted arrangement. Originally they were discovered in the coffee-family plant Oldenlandia affinis (Rubiaceae) and have since been identified in several species of the violet, cucurbit, pea, potato, and grass families. However, the identification of novel cyclotide-containing plant species still is a major challenge due to the lack of a rapid and accurate analytical workflow in particular for large sampling numbers. As a consequence, their phylogeny in the plant kingdom remains unclear. To gain further insight into the distribution and evolution of plant cyclotides, we analyzed ∼300 species of >40 different families, with special emphasis on plants from the order Gentianales. For this purpose, we have developed a refined screening methodology combining chemical analysis of plant extracts and bioinformatic analysis of transcript databases. Using mass spectrometry and transcriptome-mining, we identified nine novel cyclotide-containing species and their related cyclotide precursor genes in the tribe Palicoureeae. The characterization of novel peptide sequences underlines the high variability and plasticity of the cyclotide framework, and a comparison of novel precursor proteins from Carapichea ipecacuanha illustrated their typical cyclotide gene architectures. Phylogenetic analysis of their distribution within the Psychotria alliance revealed cyclotides to be restricted to Palicourea, Margaritopsis, Notopleura, Carapichea, Chassalia, and Geophila. In line with previous reports, our findings confirm cyclotides to be one of the largest peptide families within the plant kingdom and suggest that their total number may exceed tens of thousands.

Uterine contractility of plants used to facilitate childbirth in Nigerian ethnomedicine

Ethnopharmacological relevance Pregnant women in Nigeria use plant preparations to facilitate childbirth and to reduce associated pain. The rationale for this is not known and requires pharmacological validation. Aim of study Obtain primary information regarding the traditional use of plants and analyze their uterine contractility at cellular level. Materials and methods Semi-structured, open interviews using questionnaires of traditional healthcare professionals and other informants triggered the collection and identification of medicinal plant species. The relative traditional importance of each medicinal plant was determined by its use-mention index. Extracts of these plants were analyzed for their uterotonic properties on an in vitro human uterine cell collagen model. Result The plants Calotropis procera, Commelina africana, Duranta repens, Hyptis suaveolens, Ocimum gratissimum, Saba comorensis, Sclerocarya birrea, Sida corymbosa and Vernonia amygdalina were documented and characterized. Aqueous extracts from these nine plants induced significant sustained increases in human myometrial smooth muscle cell contractility, with varying efficiencies, depending upon time and dose of exposure. Conclusion The folkloric use of several plant species during childbirth in Nigeria has been validated. Seven plants were for the first time characterized to have contractile properties on uterine myometrial cells. The results serve as ideal starting points in the search for safe, longer lasting, effective and tolerable uterotonic drug leads.

Use of medicinal plants for the treatment of measles in Nigeria.

AIM OF THE STUDY The present study was an ethnobotanical survey of three Local Government areas of the Ijebu area of Ogun State in southwest Nigeria for plants used in the treatment of measles. MATERIALS AND METHODS Unstructured interviews were conducted among both urban and rural dwellers of three major groups of Ijebu people inhabiting the area (Ijebu North, Ijebu northeast and Ijebu Ode Local Governments). RESULTS A total of 20 respondents constituted by herbalists, herbsellers and old people that have privileged information on the plants used in the treatment of measles among children were encountered during the survey. Twenty-three plant species belonging to 18 Angiosperm families were said to possess curative properties for the cure of measles among the local populace. Amongst the most frequently used plants are Elytraria marginata Vahl, Peperomia pellucida (L.) Humb., Bonpl. & Kunth, Vernonia amygdalina Del., Momordica charantia L., Newbouldia laevis (P. Beauv.) Seem. ex Bureau, and Ocimum gratissimum L. CONCLUSION The most frequently mentioned family is Cucurbitaceae. The mode of preparation and recommended dosages are enumerated in this paper. The results of the study call for an urgent need of the introduction of a strategy for the conservation of indigenous medicinal plants in the area.

Comparative Analysis of the Oils of Three Ficus Species from Nigeria

Abstract The oil composition of three Ficus species (Moraceae): Ficus lutea Vahl., Ficus polita Vahl., and Ficus thonningii Blume., were studied by GC and GC/MS. The main compounds in F. lutea were acorenone B (20.7%) and phytol (16.2%), with significant quantities of demethoxyageratochromene (6.0%), 6, 10, 14-trimethyl-2-pentadecanone (5.1%) and zingiberene (5.2%). However, F. polita had phytol (23.3%) and 6, 10, 14-trimethyl-2-pentadecanone (15.0%) in abundance, in addition to sizeable proportions of (E)-6, 10-dimethyl-5, 9-undecadien-2-one (7.3%) and drimenol (5.8%), while F. thonningii comprised 6, 10, 14-trimethyl-2-pentadecanone (18.8%) and phytol (14.7%). Acorenone B (7.6%) and β-gurjunene (6.3%) were also observed in higher amounts. Phytol and 6, 10, 14-trimethyl-2-pentadecanone seem to be the marker components of Nigerian grown Ficus species as it is evident in this report and previous studies.

Analysis of taxonomic and geographic patterns of Turkish Veronica orientalis using nuclear and plastid DNA and morphological data

Veronica orientalis and related species form one of the taxonomically most challenging subgroups within the genus Veronica. Hybridization and polyploidization on the one hand and convergent character evolution on the other have made delimitation of species difficult. Amplified fragment length polymorphisms and plastid DNA markers were used in conjunction with 54 morphological characters to study relationships among 35 accessions of V. orientalis Mill. as well as other closely related species of Veronica occurring in Turkey and adjacent areas of Georgia and Armenia. In addition, ploidy levels were estimated for 15 accessions using flow cytometry. Diploid to hexaploid individuals were detected in V. orientalis. Analysis of DNA markers demonstrated the non-monophyly of V. orientalis, especially with regard to V. fuhsii and V. multifida from Eastern Turkey, but nuclear and plastid DNA markers are largely incongruent. Neither demonstrates a clear biogeographic pattern. The morphological analysis reveals the distinction of V. orientalis subsp. carduchorum, which is weakly retrieved in some molecular analyses and some clustering according to geography. V. multifida is not monophyletic likely due to parallel evolution of pinnatifid leaves east and west of the Anatolian diagonal.

Antipsychotic property of solvent-partitioned fractions of Lonchocarpus cyanescens leaf extract in mice

Abstract Background: This study was carried out to evaluate the antipsychotic property of solvent-partitioned fractions of the leaf extract of Lonchocarpus cyanescens (LC), a reputable medicinal plant used in folk medicine for the treatment of mental illnesses in Nigeria. Methods: The n-hexane fraction, ethyl acetate fraction (EAF), and aqueous ethanol fraction (AEF) of LC were tested for antipsychotic property based on the antagonism of stereotypy induced by apomorphine (APO). Antagonism of hyperactivity and lethality in aggregated mice induced by amphetamine (AMPH) were further employed for screening the antipsychotic effect of the fractions. EAF was tested for catalepsy utilising the horizontal plane paradigm. Thin-layer chromatography (TLC) was used to screen EAF for the presence of secondary metabolites. Results: AEF (100–400 mg/kg) significantly (p<0.05) suppressed stereotypy induced by APO (2 mg/kg, intraperitoneal [IP]) in comparison with control, suggesting antipsychotic activity. However, EAF (200 mg/kg, IP) was most potent in inhibiting the stereotypic effect of APO. EAF was also the most active in antagonising AMPH-induced hyperactivity and in protecting against death caused by AMPH in grouped mice. However, in contrast to haloperidol, EAF did not produce cataleptic behaviour in the horizontal plane paradigm. The TLC analysis revealed that EAF contains several compounds, with some of them having Rf values similar to that of haloperidol, which suggests the presence of active substances with the same chemical structural identity. Conclusions: These findings suggest that EAF contains the major active constituent(s) mediating the antipsychotic property of LC and further support its use for the management of psychosis in traditional medicine.

A pharmacobotanical study of two medicinal species of Fabaceae

OBJECTIVE To carry out a pharmacobotanical study of Lonchocarpus cyanescens (Schum & Thonn) Benth (L. cyanescens) and Leptoderris micrantha Dunn (L. micrantha) which are two key medicinal plants from the family Fabaceae. METHODS The epidermal peel was obtained by soaking the leaf in concentrated nitric acid (HNO3) in a petri dish. Both surfaces were carefully mounted on clean glass slides and dehydrated by ethyl alcohol, and stained with safaranin O for 2 min. Transverse sections of plant leaf were obtained by free hand sectioning. Phytochemical screening for various constituents was carried out on the powdered leaves. Other parameters such as, moisture content, ash value, acid insoluble ash, water-soluble ash, water and alcohol extractive values were obtained by standard techniques. RESULTS THE DISTINCTIVE FEATURES OF THE SPECIES INCLUDE: the presence of stomata on both surfaces of L. cyanescens and the absence in L. micrantha. Presence of larger epidermal cells in both upper and lower surfaces of L. cyanescens [(35.25±1.64)×(31.25±2.36), (43.0±2.63)×(39.5±5.11)] respectively compared to L. micrantha. Glandular multicellular trichomes are present in L. micrantha but absent in L. cyanescens. Numerous trichomes surround the transverse section of the leaf of L. micrantha but absent in L. cyanescens. Preliminary phytochemical screening showed that both species contain secondary metabolites such as alkaloids, anthraquinones, cardiac glycosides, tannins, saponins, steroids and flavonoids. CONCLUSIONS The microscopic and phytochemical data provided in this study are useful for the standardization of the medicinal plants.

Integration of ploidy level, secondary metabolite profile and morphological traits analyses to define a breeding strategy for trifoliate yam (Dioscorea dumetorum (Kunth) Pax)

The literature in recent times lacks adequate report on the utilization and genetic improvement programmes on Dioscorea dumetorum . Despite the wide application of this yam species in agriculture and medicine, it suffers neglect while other species are becoming increasingly popular. Therefore, it is pertinent to focus on research that will bring this species to the limelight. The aim of the present study was to evaluate the ploidy levels, morphological traits and secondary metabolite profile of 53 accessions of D. dumetorum from six countries in West and Central Africa. Ploidy levels were determined using flow cytometry. Overall, 18 morphological traits were recorded from the above- and underground parts of the plant. The 53 accessions were subjected to statistical analyses using the data on ploidy levels, morphological traits and qualitative phytochemical screening. A total of 15 accessions from the generated clusters were selected for thin layer chromatographic and quantitative phytochemical analyses. The analyses revealed diploid (2 x ) and triploid (3 x ) levels in these accessions. The pruned dendrogram derived from agglomerative hierarchical clustering based on the distance matrix revealed three main groups, showing a relationship between sex and ploidy level in the accessions and exhibiting sufficient cluster variability that may be important in designing breeding programmes. The crop was also shown to possess metabolites such as alkaloids, saponins and flavonoids, which are known to be useful in the application of phytomedicine. Genetic variability observed among the yam accessions in this study can be used for breeding purposes and to broaden the genetic basis of the crop for efficient utilization of the genetic potential possessed by this species.

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

Ethnopharmacological relevance 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. Aims of study (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. Materials and methods 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. Results 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. Conclusion 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.

Antioxidant and acetylcholinesterase inhibitory activities of leaf extract and fractions of Albizia adianthifolia (Schumach) W.F. Wright.

Abstract Background: This study was conducted to determine the antioxidant and acetylcholinesterase inhibitory activities of the leaf extract and different fractions of Albizia adianthifolia (Schumach.) W. Wright, and also to identify and quantify some phenolic compounds in the extract. Methods: The antioxidant and acetylcholinesterase inhibitory activities of the methanol extract (CME), ethyl acetate (EAF), chloroform (CHF), and n-hexane (NHF) fractions of A. adianthifolia leaves were subjected to in vitro chemical analyses. Results: Phytochemical screening revealed important classes of secondary metabolites. All extracts showed good antioxidant and acetylcholinesterase inhibitory activities. The EAF and CHF gave the highest total phenolic contents of 18.02±0.14 and 18.43±0.95 mg gallic acid equivalent per gram of extract, respectively. The polar extracts gave the highest activity in both assays with lower IC50 values. In the 2,2-diphenyl-1-picrylhydrazyl free-radical scavenging activity assay, the IC50 values of CME, EAF, CHF, and NHF were 77.74±0.84, 55.76±2.30, 58.47±0.72, and 232.24±2.70 µg/mL, respectively, while in the acetylcholinesterase inhibitory assay, the IC50 values of CME, EAF, CHF, and NHF were 11.80±0.88, 10.04±1.67, 17.44±1.74, and 124.38±1.51 µg/mL, respectively. Conclusions: The results of this study suggest that the leaf of A. adianthifolia could serve as a potential candidate for future search of antioxidant and acetylcholinesterase inhibitors for the management of neurodegenerative disorders such as Alzheimer’s disease.