Bulbine abyssinica, Bulbine frutescens and Bulbine natalensis of the Asphodelaceae family have been used for many years, traditionally for the treatment of skin related conditions such as wounds, scars, burns ad rashes. To date, these plants have been studied for various medicinal properties, including antioxidant, antimicrobial, anti-inflammatory, anti-diabetic and even anti-platelet activity. This review article aims to discuss the ethnobotanical uses and medicinal activity from the perspective of abiotic stress impacts, specifically elevated carbon dioxide and high temperature. Literature sources obtained from Google Scholar, Science Direct, theses and books were used to search for the ethnobotanical, traditional uses, and pharmacological studies of the species. In addition, articles around the concurrent and separate studies of elevated CO₂ and temperature impacts on medicinal activities of other medicinal plant species were also sourced for reference purposes because there have not been any reported studies discussing the impacts of the aforementioned abiotic factors on the species.

Introduction: Portulacaria afra is a medicinal plant commonly used among African traditional healers to treat skin conditions and dehydration. The aim of this study was to scientifically validate the use of P. afra among traditional healers. Methods: Standard phytochemical colour tests were used to determine the presence of ten phytochemicals, using four solvents of varying polarities (hexane, ethyl acetate, methanol, and water). The antioxidant activity was determined using 1-diphenyl-2-picrylhydrazyl (DPPH) and hydrogen peroxide scavenging assays. An agar-well diffusion assay was used to determine the antibacterial activities of the leaves, stems, and roots of P. afra against Staphylococcus aureus and Escherichia coli. Results: P. afra exhibited a high phytochemical presence in the methanolic extracts, with seven out of the 10 phytochemical groups present. Flavonoids and phlobatannins were absent in all of the plant’s extracts. The methanolic root extract exhibited the highest DPPH scavenging activity (IC50=0.39) whilst the hexane leaf extract (IC50= 14.83) was the only extract to exceed the acceptable upper limit. The scavenging activity of the plant was stronger against hydrogen peroxide than it was against DPPH. The methanolic and hot water stem extracts displayed the largest zone of inhibition (of 20 mm) against E. coli. The cold-water and room-temperature water extracts, of all three plant parts, showed no zone of inhibition against either bacterial strain. Conclusion: P. afra has the capacity to be used as a nutritional supplement for its antioxidant properties, while the antibacterial properties may provide relief against E. coli infections.

Bulbine abyssinica is a succulent medicinal plant indigenous to South Africa. The species has been commonly used traditionally by indigenous people for the treatment of various skin related ailments as well as the management of diabetes mellitus. To date, limited studies have been conducted on the underground stems and roots, as well as comparative analyses across the different plant parts of the species. Methanolic extracts of B. abyssinica leaves, underground stems and roots were used to perform phytochemical screening, quantitative phytochemical analyses, antioxidant and antibacterial assays. The leaves contained most of the phytochemical groups tested, as well as higher total phenolic (1841.7 ± 4.8 mg/100g GAE), total flavonoid (809.2 ± 75.6 mg/100g QE), total tannin (2850 ± 70.01 mg/100g GAE) and total proanthocyanidin (636.67 ± 1.67 mg/100g CE) contents compared to the underground stems and roots. The antioxidant activity results showed that the roots exhibited the strongest scavenging power against 2, 2 diphenylpicryhydrazyl (DPPH) (0.105 ± 0.01 mg/ml), whereas the leaves showed a higher antioxidant power against hydrogen peroxide (0.66 ± 0.07 mg/ml) and metal chelating radicals (2.68 ± 0.16 mg/ml). All three plant parts showed intermediate zones of inhibition (10 - 19 mm) against Staphylococcus aureus and Escherichia coli. The current study validates the use of different plant parts of B. abyssinica in the traditional medicine context, and suggests the plant’s potential application in the pharmaceutical and cosmetic industries.