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• Excellent antioxidant and scavenging activity displayed by majority of the extracts. • Most extracts displayed high anti-xanthine oxidase activity outperforming quercetin. • Moderate 15-LOX inhibition was displayed by extracts from four species. • At some degree, all tested extracts preserved the activity of the COX-1 enzyme. • Majority plants displayed selective inhibition against the COX-2 enzyme. Six indigenous medicinal plants species, Agapanthus inapertus, Cheilanthes hirta, Crassula capitella, Eriospermum flagelliforme, Euphorbia clavarioides and Pelargonium alchemilloides are used traditionally in South Africa to treat wounds without scientific evidence as wound healing agents. Consequently, this study sought to investigate the antioxidant and anti-inflammatory activities of these plants species as a first step towards their validation as wound healing agents. The 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO), ferric reducing antioxidant power (FRAP), and β-carotene-linoleic acid model system (β-CLAMS) assays were used to test for antioxidant activity. The inhibition of the xanthine oxidase (XO), cyclooxygenase -2 (COX-2) and 15- lipoxygenase (15-LOX) as well as the extracts' ability to preserve the cyclooxygenase-1 (COX-1) enzyme activity were used as anti-inflammatory models. Furthermore, the total phenolics, flavonoids and proanthocyanidins content were quantified using standard methods. Species, C. hirta displayed high flavonoid and proanthocyanidin content whilst C. capitella displayed high phenolic content, and good activity against the four used antioxidant models compared to standards, butylated hydroxytoluene and ascorbic acid. Majority of the extracts displayed significantly higher anti-xanthine oxidase activity, outperforming standard quercetin. The acetone extracts of A. inapertus (IC 50 = 57.33 ± 0.30 µg/mL), E. flagelliforme (IC 50 = 52.10 ± 0.98 µg/mL), P. alchemilloides (IC 50 = 58.28 ± 0.94 µg/mL) and E. clavarioides water (IC 50 = 50.53 ± 0.47 µg/mL) extract displayed moderate 15-LOX inhibition compared to standard, nordihydroguaiaretic acid (IC 50 = 0.45 ± 0.01 µg/mL). The acetone extracts of C. capitella (IC 50 = 3.16 ± 0.06 µg/mL), E. flagelliforme (IC 50 = 1.13 ± 0.09 µg/mL) , E. clavarioides (IC 50 = 1.84 ± 0.18 µg/mL), P. alchemilloides (IC 50 = 1.13 ± 0.14 µg/mL), and the E. clavarioides water extract (IC 50 = 1.18 ± 0.11 µg/mL) displayed COX-2 inhibition comparable to that of standard, aspirin (IC 50 = 1.11 ± 0.03 µg/mL). At some degree, all tested extracts preserved the activity of the COX-1 enzyme with the E. clavarioides acetone extract significantly preserving the activity of COX-1 (IC 50 = 96.21 ± 0.18 µg/mL), compared to standard, aspirin (IC 50 = 0.98 ± 0.06 µg/mL). The antioxidant and anti-inflammatory activities displayed by these medicinal plants support their application and beneficial effect in wounds healing and hold promising prospects as natural alternatives to the existing conventional treatments. [ABSTRACT FROM AUTHOR]

Fusarium circinatum Nirenberg and O’Donnell is an important pathogen of pine seedlings and cuttings in South Africa. The fungus causes plant death in nurseries, as well as during establishment of pine plantations. The aim of this study was to consider the effects of wound type, spore concentration, and environmental stress on infection incidence. Pine seedlings were inoculated using three wounding methods and five spore concentrations. Inoculated seedlings were incubated under optimal environmental conditions, suboptimal conditions, and suboptimal conditions combined with a fungicide treatment. Results showed that the mean percentage infection caused by increasing spore concentrations can be described by the Michaelis–Menten function. The gradient of the function, as well as the asymptotic maximum level of infection, was dependant on environmental stress and the physiological state of the host, as well as the wounding method. Spore concentration had the highest influence on infection incidence in physiologically stressed seedlings. Fungicide treatment did not influence the rate of infection incidence in comparison with the treatments conducted under optimal environmental conditions, but significantly lowered the asymptotic maximum level of infection incidence. Seedlings wounded on the stems had the highest infection incidence, when compared with other wounding methods. [ABSTRACT FROM AUTHOR]

Reports of Ceratocystis spp. causing disease of exotic plantation hardwood species have increased in recent years. Ceratocystis fimbriata causes wilt and canker on Eucalyptus spp. in Africa and South America, and C. albofundus results in wilt and death of Acacia mearnsii in Africa. Ceratocystis spp. generally infect wounds on trees, and artificial stem wounding can thus be used to determine the presence of these fungi. The aim of this study was to identify Ceratocystis spp. infecting wounds on Eucalyptus grandis in South Africa. Isolated Ceratocystis spp. were identified using morphological characteristics and comparisons of DNA sequence data for the ITS and 5·8S regions of the rRNA operon. Pathogenicity trials were conducted in the greenhouse to determine the possible role that these Ceratocystis spp. could have in disease development. These trials were also conducted under field conditions. Three Ceratocystis spp. were collected: C. fimbriata, C. moniliformis and C. pirilliformis. This is the first report of C. fimbriata and C. pirilliformis from Eucalyptus spp. in South Africa, and the first report of the latter fungus outside Australia. Both C. fimbriata and C. pirilliformis caused significant lesions on inoculated E. grandis trees. This is the first evidence that C. pirilliformis is a pathogen of Eucalyptus spp. From the results of both greenhouse and field trials, it has the potential to cause serious disease problems in Eucalyptus plantations. [ABSTRACT FROM AUTHOR]