ABSTRACT
The pantropical genus Rhynchosia belongs to the family Fabaceae and consists of approximately 230 species distributed mainly in Africa, America, and Asia. Several species of the genus have been used ethnomedicinally since 300 - 400 AD. This review presents for the first time a global overview of the extent of ethnomedicinal uses of species in the genus in addition to their phytochemistry, pharmacological activities, and toxicology. Online databases such as NCBI, PubMed, Science Direct, Scopus, SpringerLink, Taylor and Francis Online, etc., were used to source for publications on Rhynchosia species. Based on this review, 30 species (19%) are traditionally used for treating an array of ailments around the globe, most especially in Africa and Asia. Flavonoids are the most detected/isolated phytochemicals from the Rhynchosia species. Pharmacological activities such as anticancer, antidiabetic, anti-hyperlipidemic, antifungal, antioxidant, anti-inflammatory, antinociceptive, butyrylcholinesterase, as well as eye-protective and melanogenic effects were elicited by the extracts and isolated compounds from Rhynchosia species. Toxicity tests have only been carried out on R. sublobata and R. elegans extracts. Future studies should focus on the toxicological evaluation and validation of ethnomedicinal claims on the traditional uses of Rhynchosia species that have not been pharmacologically tested.
ABSTRACT
Wild indigenous vegetables have recently been receiving attention due to their accessibility and potential to fight malnutrition. The current study investigated the nutritional profile of 10 selected wild indigenous vegetables, namely Asclepias multicaulis, Lepidium africanum, Erucastrum austroafricanum, Solanum nigrum, Sonchus dregeanus, Sonchus integrifolius, Sonchus nanus, Rorippa fluviatilis, Tribulus terrestris, and Urtica lobulata, consumed by the Basotho people of southern Africa. This was done by first compiling a comprehensive literature review to identify the knowledge gaps and further analysing the selected vegetables for mineral contents and proximate compositions using standard analytical procedures of AOAC. The literature survey revealed that 90 wild plants are used as vegetables by the Basotho people, and there are knowledge gaps on the nutritional value of many species. Mineral analyses of the wild vegetables showed that Asclepias multicaulis and Sonchus dregeanus are rich in minerals such as Al, Ca, K, Mg, Na, P, and S and can compete favourably with commercialised vegetables such as lettuce and spinach in terms of mineral components. Also, all the wild vegetables studied have more than 12% recommended caloric protein value except Tribulus terrestris (10.07%) and Lepidium africanum (11.32%). The crude fat content in Asclepias multicaulis, Lepidium africanum, Rorippa fluviatilis, Erucastrum austroafricanum, and Urtica lobulata fall within the range required for healthy living. The concentrations of cadmium, copper, and lead in all the vegetables studied are below the detection level, thus making them non-toxic and safe for consumption.
ABSTRACT
The environmental and health risks associated with synthetic pesticides have increased the demand for botanical insecticides as safer and biodegradable alternatives to control insect pests in agriculture. Hence in this study, five Meliaceae species were evaluated for their insecticidal activities against the Spodoptera frugiperda and the Plutella xylostella larvae, as well as their chemical constituents. Repellence, feeding deterrence, and topical application bioassays were employed to evaluate their insecticidal activities. GC-MS analysis was performed to identify chemical compounds present in each plant. The repellence bioassay indicated that Melia azedarach extracts exhibited the highest repellence percentage against S. frugiperda (95%) and P. xylostella (90%). The feeding deterrence bioassay showed that M. azedarach and Trichilia dregeana extracts displayed excellent antifeeding activity against the S. frugiperda (deterrent coefficient, 83.95) and P. xylostella (deterrent coefficient, 112.25), respectively. The topical application bioassay demonstrated that Ekebergia capensis extracts had the highest larval mortality against S. frugiperda (LD50 0.14 mg/kg). Conversely, M. azedarach extracts showed the highest larval mortality against P. xylostella (LD50 0.14 mg/kg). GC-MS analysis revealed that all plant extracts had compounds belonging to the two noteworthy groups (phenols and terpenes), which possess insecticidal properties. Overall, this study lends scientific credence to the folkloric use of Meliaceae species as potential biocontrol agents against insect pests.
ABSTRACT
The aim of the study is to provide a revision of the genus Cynoglossum in southern Africa. The genus is taxonomically problematic within the family Boraginaceae, due to the morphological similarities it shares with other closely related genera in the family. Cynoglossum plants are low-growing biennial, perennial, or rarely annual herbs which are recognizable by their hairy stems and leaves, the latter are usually basal and long petiolate. Based on the latest checklist, a total of eight species of this genus are listed for the study region: C.alticola, C.amabile, C.austroafricanum, C.geometricum, C.hispidum, C.lanceolatum, C.obtusicalyx (endemic to South Africa), and C.spelaeum. The occurrence of C.amabile in the region, however, requires further investigation since the only existing specimen was collected within a protected area in the KwaZulu-Natal province. Two specimens collected in the Doornpoort area in Pretoria, Gauteng province, assigned to this species appear to have been misidentified. Diagnostic characters are described, correct nomenclature, synonyms, typification, distribution maps, as well as the key for identifying the studied species, are provided.
ABSTRACT
ETHNOPHARMACOLOGICAL RELEVANCE: Khaya grandifoliola is a well-known tree species in Africa with a conservation status of 'vulnerable' due to its overexploitation by the wood industry. Several studies have recorded numerous ethnobotanical uses of this plant, as well as the scientific validation of the efficacy of extracts from different plant parts used for the treatment of various ailments. However, this useful information is scattered throughout the literature and thus there is no opportunity to identify the existing knowledge gaps. AIM OF THE STUDY: This review aims to highlight the medicinal importance of Khaya grandifoliola including its known phytochemistry, biological activities and toxicology, to encourage a refocused conservation strategy since all current efforts are geared towards maintaining its continuous supply to the wood industry. MATERIALS AND METHODS: Articles on K. grandifoliola were sourced from online databases such as Google Scholar, Medicine, PubMed, Science Direct, Scopus, SciFinder and other science journal websites up to May 2020. The search was conducted using various combinations of keywords such as biotechnological uses, biological activity, ethnobotany, ethnomedicine, indigenous uses, pharmacological activity, phytochemistry, proximate composition, toxicity, and traditional uses of K. grandifoliola. All downloaded articles were screened to determine their relevance to the scope of the review and the selected papers were included. RESULTS: The review revealed a host of ethnomedicinal uses such as anticancer, antidiabetic, antimicrobial, anti-sickling, anti-ulcerogenic, and hepatoprotective, many of which are supported by scientific data. More importantly, toxicity tests revealed that many of the extracts are safe at various therapeutic doses. Important knowledge gaps that should be explored include phytochemical characterization and validation of some ethnobotanical claims on the folkloric usage of the plant. CONCLUSIONS: Notwithstanding the importance of K. grandifoliola in the wood industry, this review reveals that its use as a medicine is equally important. Its medicinal uses are also well supported with scientific studies as well as favourable toxicological studies though some scientific knowledge gaps require further studies.