Synthesis of Silver Nanoparticles Using Buchu Plant Extracts and Their Analgesic Properties

We herein report for the first time the synthesis and analgesic properties of silver nanoparticles (Ag-NPs) using buchu plant extract. The as-synthesised Ag-NPs at different temperatures were characterised by UV-Vis spectroscopy, Fourier transform infra-red spectroscopy (FTIR) and transmission transform microscopy (TEM) to confirm the formation of silver nanoparticles. Phytochemical screening of the ethanolic extract revealed the presence of glycosides, proteins, tannins, alkaloids, flavonoids and saponins. The absorption spectra showed that the synthesis is temperature and time dependent. The TEM analysis showed that the as-synthesised Ag-NPs are polydispersed and spherical in shape with average particle diameter of 19.95 ± 7.76 nm while the FTIR results confirmed the reduction and capping of the as-synthesised Ag-NPs by the phytochemicals present in the ethanolic extract. The analgesic study indicated that the combined effect of the plant extract and Ag-NPs is more effective in pain management than both the aspirin drug and the extract alone.

Phytophthora taxa associated with cultivated Agathosma, with emphasis on the P. citricola complex and P. capensis sp. nov

Agathosma species, which are indigenous to South Africa, are also cultivated for commercial use. Recently growers experienced severe plant loss, and symptoms shown by affected plants suggested that a soilborne disease could be the cause of death. A number of Phytophthora taxa were isolated from diseased plants, and this paper reports their identity, mating type, and pathogenicity to young Agathosma plants. Using morphological and sequence data seven Phytophthora taxa were identified: the A1 mating type of P. cinnamomi var. cinnamomi, P. cinnamomi var. parvispora and P. cryptogea, the A2 mating type of P. drechsleri and P. nicotianae, and two homothallic taxa from the P. citricola complex. The identity of isolates in the P. citricola complex was resolved using reference isolates of P. citricola CIT groups 1 to 5 sensu Oudemans et al. (1994) along with multi-locus phylogenies (three nuclear and two mitochondrial regions), isozyme analyses, morphological characteristics and temperature-growth studies. These analyses revealed the isolates from Agathosma to include P. multivora and a putative novel species, P. taxon emzansi. Furthermore, among the P. citricola reference isolates the presence of a new species was revealed, described here as P. capensis. Findings of our study, along with some recent other studies, have contributed to resolving some of the species complexity within the P. citricola complex, resulting in the identification of a number of phylogenetically distinct taxa. The pathogenicity of representative isolates of the taxa from Agathosma was tested on A. betulina seedlings. The putative novel species, P. taxon emzansi, and P. cinnamomi var. parvispora were non-pathogenic, whereas the other species were pathogenic to this host.