T.E. Tshikalange

In vitro anti-HIV-1 properties of ethnobotanically selected South African plants used in the treatment of sexually transmitted diseases

ETHNOPHARMACOLOGICAL RELEVANCE [corrected The plants selected in this study are used traditionally in the treatment of sexually transmitted diseases and traditional healers interviewed claimed these plants can also help AIDS patients. AIM To evaluating the in vitro anti-HIV properties of selected plants in various bioassays. MATERIALS AND METHODS The extracts were evaluated for their inhibition against alpha-glycohydrolase, reverse transcriptase and viral proteins (NF-kappaB and Tat) which play a significant role in the HIV life cycle. RESULTS Terminalia sericea extract (IC(50)=92mg/ml) exhibited a considerable alpha-glucosidase inhibitory activity which was better than acarbose (IC(50)=131mg/ml) under our assay conditions. In the reverse transcriptase assay, T. sericea also showed good inhibitory activity (IC(50)=43mg/ml), which was higher than that of the reference drug, Adriamycin (IC(50)=100mg/ml). The ethyl acetate extract of Elaeodendron transvaalense exhibited the most potent inhibitory activity in both the NF-kappaB and Tat assays with inhibitory activity of 76% and 75% respectively at a concentration of 15mg/ml. The acetone and chloroform extracts of E. transvaalense and Zanthoxylum davyi also showed good activity in the NF-kappaB and Tat assays.

Chemical compositions and antimicrobial activities of Athrixia phylicoides DC. (bush tea), Monsonia burkeana (special tea) and synergistic effects of both combined herbal teas

OBJECTIVE To determine the chemical compositions and evaluate the antimicrobial activity of bush tea (Athrixia phylicoides DC.), special tea (Monsonia burkeana) and synergy (combination of bush tea and special tea). METHODS Total polyphenols were determined using the methods reported by Singleton and Rossi (1965) and modified by Waterman and Mole (1994). Tannins were determined using vanillin HCL methods described by Prince et al. (1978). Total antioxidants were determined using the methods described by Awika et al. (2004). The micro dilution technique using 96-well micro-plates, as described by Eloff (1998) was used to obtain the minimum inhibition concentration (MIC) and minimum microbicidal concentration (MMC) values of the ethanol extracts against the microorganisms under study. The microbes strain used was Gram negative bacteria such as Escherichia coli, Klebsiella oxytoca, Proteus vulgaris, Serratia marcescens, Salmonella typhi, Klebsiella pneumonia; Gram positive bacteria such as Bacillus cereus, Staphylococcus aureus and a fungus Candida albicans. RESULTS The results demonstrated that special tea contains significantly higher content of total polyphenols (8.34 mg/100 g) and total antioxidant (0.83 mg/100 g) as compared to bush tea [total polyphenols (6.41 mg/100g) and total antioxidant (0.63 mg/100g)] and combination of bush tea and special tea [total polyphenols (6.42 mg/100 g) and total antioxidant (0.64 mg/100 g)]. There was no significant difference in tannins between bush tea, special tea and synergy. The results of antimicrobial activity (MIC and MMC) demonstrated that the ethanol extracts of bush tea, special tea and synergy possessed antimicrobial activity against all microorganisms at different zones. The MIC of bush tea ranged from 1.56 to 12.50 mg/mL while the MMC ranged from 0.78 to 12.50 mg/mL. Special teas MIC ranged from 0.39 to 12.50 mg/mL while the MMC ranged from 0.01 to 12.50 mg/mL. The MIC of synergy ranged from 3.13 to 12.50 mg/mL while the MMC ranged from 3.13 to 12.50 mg/mL without positive synergistic effect recorded. CONCLUSIONS Both bush and special tea contain total polyphenols, total antioxidants and tannins with special tea containing a significantly higher total polyphenols and total antioxidant as compared to bush tea and synergy. Bush tea, special tea and synergy possess antimicrobial activity at various degrees.

Phytochemical Constituents and Antioxidant and Antimicrobial Activity of Selected Plants Used Traditionally as a Source of Food

Many indigenous plants have also been used as a source of food and medicine in many African rural communities in the past. The study investigated the antimicrobial activity, phytochemical constituent, and antioxidant activity of selected traditional plants used traditionally as a source of food and medicine. The methanol and water extracts of different plant parts were analyzed for phytochemicals using standard phytochemical screening reagents while the broth microdilution assays were used to analyze antimicrobial activities. Alkaloids, phenols, flavonoids, saponins, tannins, and terpenes were found in one or more of the plant extracts, and all the plant extracts demonstrated scavenging activities. The back extracts of Sclerocarya birrea and the leaf extracts of Garcinia livingstonei exhibit the best antioxidant activities, while the water and methanol back extracts of S. birrea and G. livingstonei were the most active against all the tested foodborne bacteria.

Effect of Timing and Rates of Nitrogen Application on Yield, Chemical Compositions, Pharmacologic Activities, and Cytotoxicity of Herbal Bush Tea (Athrixia phylicoides DC.)

Bush tea is a popular South African herbal and medicinal tea with the potential for commercialization. The objective of the study was to investigate the effects of different rates of applied nitrogen (N) and timing (early and late) of N application on yield, chemical composition, pharmacologic activity, and cytotoxicity of bush tea. Factorial treatments consisted of timed N application rates (0, 75, 150, and 225 kg·ha) for both early and late N application. The treatments were arranged in a randomized complete block designwith five replicates. The results show a significant positive response of bush tea fresh and dry leaf and twig weight, chlorophyll, leaf tissue N, total polyphenols, and total flavonoids in response to applied N rates, regardless of the timing of N application, reaching a maximum at 225 kg·ha of N. Later, regardless of the timing of N application, total tannins and total antioxidant activity increased with increasing applied N from 0 to 225 kg·ha, reaching a maximum of 150 kg·ha N. The results of this study suggest that, with the exception of antimicrobial activity, most of the parameters recorded increased with increasing rates of N applied. The results further denote that parameters recorded were consistently greater on early applied N compared with late applied N. However, there was no significant difference between the minimum inhibition concentration (MIC) and minimum microbicide concentration (MMC) of early and late appliedN. Bush tea appliedwith 75 N and 150 N had a significantMIC value (3.1mg·mL) for Escherichia coli and Klebsiella pneumonia compared with 6.3 mg·mL reached at 225 kg·ha N. Among N rates applied, the MIC for Klebsiella oxytoca, Proteus vulgaris, Salmonella typhi, Serratia marcescence, and Staphylococcus aureus were not significantly different. Hence, N rates applied did not have a significant effect on bush tea MMC values of all microbial species tested. The cytotoxicity of bush tea leaf and twigs harvested from early and late N application were significantly reduced with increasing nitrogen levels reaching a maximum at 225 kg·ha. There was a wide variation of compounds despite rates of N applied as well as timing of application, with most compounds such as norfenfluramine, phytol, caryophyllene, propylene glycol, a-copaene, and squalene detected in greater quantities. Bush tea is a South African herbal tea with the potential for commercialization. The commercialization of bush tea is supported by a report of the toxicologic assessment of bush tea conducted by Chellan et al. (2008). They have reported widespread consumption of bush tea in South Africa. Mudau et al. (2007) also reported that commercialization of bush tea can provide a healthy beverage alternative to caffeine-containing teas. The plant is used popularly as an herbal tea and a medicinal plant for the treatment of different ailments (Nchabeleng et al., 2013). Naturally, bush tea grows at different altitudes with different rainfall regimes and soil characteristics (Nchabeleng et al., 2012). Therefore, to achieve good-quality bush tea, it is important to study the nutritional requirement of field-grown bush tea plants. Fertilizers play a critical role in determining horticultural crop yield, quality, and nutritional content (Martinez-Ballestra et al., 2008). In general, all major quality attributes in horticultural crops, including visual quality and taste, are influenced directly by N availability (Locascio et al., 1984). In green tea production, fertilizer is a major agro-input for the production of high-yield and high-quality tea (Woldegebriel, 2007). Fertilizers improve the nutritional status of both soil and plants (Njogu et al., 2014). Because tea production is a perennial monoculture, a well-balanced fertilizer is necessary throughout the year (Hamid et al., 2014). The production of secondary metabolites in medicinal plants has been reported to be influenced by genetics and cultivation conditions, such as climate, plant density, and the use of fertilizers (Baranauskiene et al., 2003). Among fertilizers, N is the most important nutrient for crop production because it promotes both yield and quality of plant secondary metabolites (Sifola and Barbieri, 2006). The reason for extensive N application is that the quality of green tea is known to correlate directly with the concentration of primary compounds related to N application (Watanabe, 1995). In addition, N is a wellknown essential element for plant growth and it plays a regulatory role in the synthesis of secondary metabolites, such as phenolic compounds (Ruan et al., 2010). Conversely, Bryant et al. (1983) hypothesized that high N levels in plant tissues contribute to the formation of more amino acids and proteins for growth in relation to defense compounds such as secondary metabolites. Previous studies demonstrated that earlyapplied N levels ranging from 75 to 225 kg·ha improved growth and quality in cultivated bush tea (Tshivhandekano et al., 2017). However, data are lacking to demonstrate the effect of timing and rates of N application on bush tea. Thus, this study aimed at investigating the effect of applied N rates and timing of N application on yield, chemical compositions, pharmacologic activity, and cytotoxicity of bush tea. Materials and Methods Experimental site. The experiments were conducted at the Tshwane University of Technology (TUT) experimental farm, which is situated north of Pretoria (lat. 25 36#03.2

Nitrogen application influences quality, pharmacological activities and metabolite profiles of Athrixia phylicoides DC. (Bush tea) cultivated under greenhouse and field conditions

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Antimicrobial, Antioxidant, and Cytotoxicity Properties of Selected Wild Edible Fruits of Traditional Medicinal Plants

E). The trials were conducted beginning in spring (Sept. 2016) to the end of Nov. 2016. The plants were allowed to resprout and the trial was repeated beginning in the summer (Dec. 2016) until the end of the summer season (Feb. 2017). The resprouted shoots were fertilized in the same manner as the initial plants. Weather data are presented in Table 1; this was the best time to cultivate bush tea in South Africa (Mudau et al., 2006, 2007). Five soil samples were collected per horizon (A and B) from different spots on the plot the trial was conducted. Each soil sample collected was packed separately in different marked brown paper bags. The initial soil chemical analyses were conducted using the procedure described by Hanlon et al. (1994). The soil contained 0.001 mg·kg nitrate-N. Received for publication 2 Mar. 2018. Accepted for publication 10 July 2018. We gratefully acknowledge the financial support of the National Research Foundation, the Gauteng Department of Agriculture and Rural Development, and Stellenbosch University’s Division of Research Development. Corresponding author. E-mail: mudaufn@unisa. ac.za. 1332 HORTSCIENCE VOL. 53(9) SEPTEMBER 2018 Other soil chemical characteristics are presented in Table 2. Experimental design and treatment details. Factorial treatments consisted of timed N application rates (0, 75, 150, and 225 kg·ha) for both early and late N application. Applied N rates were 0, 75, 150, and 225 kg·ha per plot of 36 plants spaced at 0.5 · 0.5 m. The N rates were timely (early and late) manually broadcasted once off. Early (3 weeks after plant establishment) and late (6 weeks after plant establishment) N application was conducted in a randomized complete block design with five single plants per treatment replicated five times. Limestone ammonium nitrate (28% N) was used as an N fertilizer source. All plants received 75 kg·ha phosphorus (P) and 45 kg·ha potassium (K). The fertilizer source for P was single superphosphate (10.5%); for K, it was potassium chloride (50%) [Ocean Agriculture (PTY) LTD, Muldersdrift, South Africa]. Micronutrients were foliar applied as recommended by Maedza et al. (2017). Two liters of water per plant was applied every third day using a drip irrigation system. Plant material. The plant materials were collected from Haenerstburg (lat. 23 56# S; long. 29 54# E; 890 m a.s.l.) in Limpopo Province, South Africa. Plants were propagated by using cuttings as described byMudau et al. (2006). Bush tea cuttings 7 to 8 cm long were planted as described by Maudu et al. (2012), with sand used as the growth media. The cuttings were placed on the mist bed and allowed to sprout and root. The well-matured bush tea that hardened in the shade nets after propagation were later transplanted to the TUT experimental farm for the open field trial, using a plant spacing of 0.5 · 0.5 m. Parameters recorded. Biomass (fresh and dry weight of leaf and twigs), chlorophyll content, leaf tissue N, total polyphenols, total flavonoids, total tannins, antioxidant activity, antimicrobial activity, cytotoxicity, and detected compounds were documented. Determination of chlorophyll content. Chlorophyll was measured once every month during the growing seasons with a portable Minolta chlorophyll meter (SPAD-502; Spectrum Technologies, Inc., Plainfield, IL). Determination of fresh weight and dry weight. The average fresh and dry weights were determined used standard level precision balances. Fresh weight was measured immediately after harvest whereas dry weight was measured after 2 weeks of freeze drying. Harvest and extraction of bush tea leaf and twig samples. The bush tea leaves and twigs were harvested using the current traditional method of cutting the plant from the stem to allow resprouting. The bush tea leaves and twigs from both early and late applied N plots were all harvested at the end of spring (Nov. 2016) and the end of summer (end of Feb. 2017). During harvest, the leaves and twigs were packed in marked brown paper bags. After harvest, bush tea leaves and twigs were transported immediately to the science campus of the University of South Africa in Florida (lat. 5.26 9#501

Antimicrobial activity, toxicity and the isolation of a bioactive compound from plants used to treat sexually transmitted diseases.

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Antimycobacterial, antibacterial and antifungal activities of Terminalia superba (Combretaceae)

E), where they were weighed and freeze-dried for 2 weeks. One hundred grams of blended leaf materials was soaked in 150 mL ethanol and shaken at room temperature for 24 h. The ethanol supernatant was filtered and then evaporated on a rotary evaporator under reduced pressure at 37 C. The extract was store

Synthesis and HIV-1 reverse transcriptase inhibition activity of 1,4-naphthoquinone derivatives

ABSTRACT Bush tea (Athrixia phylicoides DC.) is a popular aromatic plant, indigenous to South Africa. For many decades, indigenous people have widely consumed the tea as a healthy beverage and a medicine. The objective of the study was to investigate the influence of nitrogen fertiliser application on the quality, pharmacological activities and metabolite profiles of the leaves and twigs of bush tea cultivated under greenhouse and field conditions. Treatments consisted of 0, 75, 150, 225, 300 and 375 kg/ha N, arranged in a randomised complete block design with five replicates. Parameters measured were leaf tissue nitrogen, total polyphenols, total flavonoids, total tannins, total antioxidants, antimicrobial activity and cytotoxicity. In addition, metabolites were identified and measured using gas chromatography linked to mass spectrometry (GC-MS) and liquid chromatography linked to mass spectrometry (LC-MS). The results of this study showed a significant quadratic response of total polyphenols, total flavonoids, total tannins and total antioxidants of bush tea leaves and twigs, irrespective of the growth environment ranging from 150 to 225 kg/ha N. The results further suggested that, despite the growing environment, nitrogen treatments did not improve the minimum inhibition concentration and minimum microbicide concentration of bush tea with extract concentrations ranging from 25.0 to 3.1 mg/g. Bush tea was found to be non-toxic (IC50 above 100) under both growing conditions, irrespective of nitrogen treatments. Despite trials being conducted under greenhouse and field conditions and with different nitrogen treatments, there were no distinct differences regarding the gas chromatography linked to mass spectrometry and liquid chromatography linked to mass spectrometry compounds. The future aims of the study are to investigate the effects of nitrogen fertilisation, the timing of nitrogen fertilisation and the planting density on the yield, quality, plant metabolites and pharmacological activity of field-grown bush tea.

Antioxidant activity and cytotoxicity of three flavonoids from Athrixia phylicoides ethanol extract

ABSTRACT The fruit pulp extracts of 12 wild edible fruits were investigated for their antimicrobial, antioxidant, and cytotoxic properties. Methanol extracts of the pulps were tested against five microorganisms (Salmonella typhi, Streptococcus pyogenes, Bacillus cereus, Klebsiella pneumonia, and Prevotella intermedia). The fruit pulp extracts of the wild edible plants exhibited different degrees of antimicrobial activity, with Adansonia digitata exhibiting considerable antimicrobial activity against Salmonella typhi. The fruit pulp extracts of A. digitata were also the highest in antioxidant activity. None of the fruit pulp extracts was toxic to humans. The results show the potential use of these fruit pulps for the development of functional foods with medicinal benefits.