No abstract

Combretaceae is a large Angiosperm family that is highly sought after because of its pronounced medicinal value. Combretum is recognized as the largest genus, prevalent in southern Africa due to its extensive use in traditional medicine. This study aimed to provide a comparative analysis of the phytochemical constituents of the leaf and stembark extracts of Combretum erythrophyllum (Burch.) Sond. Leaf and stembark crude extracts were generated using hexane, chloroform, and methanol as the solvents of choice. Qualitative phytochemical tests indicated the presence of phytocompounds, including carbohydrates, alkaloids, sterols, phenols, fixed oils, and fats. Flavonoids were found within the leaf extracts only, while saponins, mucilage, and gums were specifically identified within the stembark extracts. The first reported gas chromatography–mass spectrometry (GC–MS) screening of C. erythrophyllum leaf and stembark extracts was conducted, yielding the identification of 266 phytocompounds. Major phytocompounds such as sitosterol and lupeol, which may have possible anti-cancer and anti-inflammatory properties, were identified. Furthermore, a pharmacogenetic evaluation was conducted. As a result, both the leaf and stem bark material were seen to fluoresce a wide array of colors (brown, red, green, and blue colorations), indicating the presence of beneficial phytometabolites and their use in medicinal applications. Given the wide array of proposed medicinal benefits associated with the presence of phytocompounds identified within C. erythrophyllum, this species should be considered for its medicinal importance. The isolation and extraction of these beneficial compounds open further avenues for their use in the pharmaceutical industry.

No abstract

Background: Medicinal plants are known to contain numerous phytometabolites with suggested pharmacological value. Literature suggests that the medicinal use of phytometabolites in its natural state has limited success due to poor absorption rates. Currently, the focus lies on synthesizing phytometabolites extracted from medicinal plants and silver ions to generate nano- scale carriers with specialized properties. Thus, the nano-synthesis of phytometabolites with silver (Ag+) ions is proposed. The use of silver is promoted due to its known antibacterial and antioxidant effectiveness, among many. Nano technology allows for the green generation of nano-scaled particles that are able to penetrate target areas due to its size and unique structure. Objective and Methodology: A novel protocol for the synthesis of silver nanoparticles (AgNP’s) using the leaf and stembark extracts of Combretum erythrophyllum was established. The generated AgNP’s were characterised using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Energy-dispersive X-ray (EDX), Nanoparticle tracking analysis (NTA), and UV Spectrophotometry (UV -vis). Furthermore, the AgNP’s were evaluated for their antibacterial, cytotoxic and apoptotic activity against a range of bacterial strains and cancer cells. Characterisation was based upon particle size, shape and elemental silver composition. Results: Within the stembark extract, synthesised nanoparticles were large, spherical in shape and dense in elemental silver composition. While synthesised nanoparticles of the leaf extract were small to medium in size, varied in shape and contained minimal quantities of silver (substantiated by the TEM and NTA results). Furthermore, it was established that the synthesized nanoparticles exhibited high antibacterial properties due to the conducted antibacterial assay. The FTIR analysis revealed the presence of numerous functional groups within active compounds found in the synthesised extracts. Functional groups found varied between the leaf and stembark extracts, each with proposed pharmacological activity. Conclusion: Presently, antibiotic resistant bacteria are continuously evolving thus, posing as a threat to conventional drug delivery systems. Nanotechnology provides a platform that enables the formulation of a low toxicity and hypersensitive drug delivery system. Further studies evaluating the biological activity of extracts of C. erythrophyllum synthesized with silver nanoparticles could enhance its proposed pharmaceutical value.

Species of Combretum are highly valued in Africa due to the plethora of traditional medicinal uses they may offer and the medicinally important phytometabolites they are known to contain. Traditionally, C. erythrophyllum is used to treat bacterial infections, venereal diseases, abdominal pain, sores, infertility, and labour pains, while displaying, anti-viral, anti-parasitic, cytotoxic, and mutagenic activities. There are numerous published works available on the bioactivity of phytometabolites of the leaf extracts of C. erythrophyllum; however there have been limited or no studies published on the bioactivity of the stembark. Hence, this study aimed to provide a comparative analysis of the biological activity of the leaf and stembark extracts of C. erythrophyllum. The following characters were evaluated through the emanating study: total flavonoid and phenolic content, as well as the antioxidant, cytotoxic, and apoptosis activities of the leaf and stembark extract. Methanolic extracts appeared to have the highest possible antioxidant potential among all of the tested extracts and displayed the lowest IC50 values (leaf 5.29 and stembark 4.29 µg/mL) when evaluated using the DPPH assay, the methanolic extracts appeared to quantify the largest amount of compositional phenolic content (1341.05 ± 4.4 mg/GAE/g). Methanolic extracts were the best performing, with the overall lowest IC50 values when tested against HeLa and HEK293 cells (leaf 54.53 µg/mL and stembark 18.30 µg/mL). A positive correlation between % inhibition and extract concentrations was noted for all of the assays. The extent/level of antioxidant activity was seen to be directly proportional to the flavonoid and phenolic content. Extracts with the highest total phenolic content appeared to display the strongest cytotoxic activity. This study integrated the use of fluorescence microscopy with acridine orange staining in order to accurately determine the viability of cells. A direct correlation was observed between the results obtained from the cytotoxicity and apoptosis assay. It may be concluded that the antioxidant properties, total phenolic, and total flavonoid content were directly proportional to the apoptotic and cytotoxic activity expressed by the tested extracts. Focus should now be placed on isolating phytocompounds of importance from the best performing extracts. The transformation of an isolate into a drug of pharmacological importance has yet to be appraised on a large scale. Therefore, further evaluation of this species and particularly the transformation of the isolates needs to be explored as this species has shown immense medicinal potential.