Indigenous South African Plant Research Articles

Multi-stakeholder value creation and appropriation from food-related health claims

Health claims are considered a means to add value to food and beverages; however, it is not always evident which stakeholders benefit and to what extent they benefit. In this paper, we extend the investigation of value creation and appropriation into the domain of food, specifically food labels. Using a qualitative approach, we aimed to elucidate which forms of value can be created by legislating health claims (including those for bioactive compounds found in South African indigenous plants) on food labels. The findings reveal that health claims have the potential to advance the sustainable development agenda in South Africa, but only if structures can be put in place to appropriate human and intellectual (HI) value, as well as environmental value. Currently, there is strong evidence for economic value creation and appropriation potential, but little clear evidence that HI or environmental value will be appropriated from health claims, especially if these health claims exclude benefits from bioactive compounds found in indigenous South African plants. If we could find a means to measure the HI and environmental value creation potential of health claims, using metrics that people understand, we may be able to develop strategies to ensure that such products can benefit stakeholders beyond economic value alone (i.e. more sustainable value creation). The findings could directly impact food labelling policy formulation, considering current draft regulations to implement health claims in South Africa.

Positioning research and Scholarly Innovation within a “transdisciplinary” approacht

Based on the shared expertise of two research entities at the Cape Peninsula University of Technology (CPUT) a transdisciplinary (TD) research approach was adopted to investigate whether Rooibos an indigenous South African plant with its unique bioactive compounds modulates oxidative stress and potentially acts as an ergogenic supplement. Due to the nature of this unique biotechnology and sport business collaboration along with support from the South African Rooibos Council (SARC) and associated academic stakeholders, various beneficial outcomes were anticipated, including: 1) to provide scientific findings informed by the innovative technologies that measure metabolic and gene-diet interaction responses to phenolic-rich Rooibos; 2) to assess the potential of Rooibos to modulate oxidative stress during exercise and underscore its anticipated ergogenic properties; 3) to utilize scientifically derived evidence to beneficiate Rooibos in the lucrative sport supplement market; 4) to provide rationale to optimize the equitable sharing of benefits derived from Rooibos to the relevant indigenous communities, and 5) to enhance sustainable economic benefits derived from various policy enactments including the Protected Designation of Origin (PDO) status. The findings from two randomized double-blinded placebo controlled intervention trials provide a strong indication that the unique bioactive compounds of Rooibos may have benefits for exercise performance and recovery and as a potential ergogenic supplement, which may have further positive ramifications for the Rooibos value chain in terms of beneficiating Rooibos. Additionally, the TD approach has acknowledged the importance of indigenous biological resources, and the commitment to share sustainable economic benefits with traditional knowledge holders in a fair and equitable way.

Susceptibility patterns of Escherichia coli and streptococcal isolates from bovine mastitis cases to antibiotics and selected South African plant extracts with known antibacterial activities

Bovine mastitis, an inflammatory condition affecting the mammary glands of dairy cattle, poses a significant economic burden on the dairy industry. Staphylococcus species, Streptococcus species and Escherichia coli are common pathogens. Managing mastitis typically involves antibiotics, but antimicrobial resistance (AMR) is a growing concern, promoting further research exploring alternative treatments including plant extracts. This study aimed to determine the antibiotic resistance of E. coli and streptococcal isolates from mastitis cases, and to investigate four indigenous South African plants for their selective antibacterial activities against these pathogens. The antimicrobial susceptibility of the bacterial strains was determined using a standard disc diffusion method. Minimum inhibitory concentration (MIC) values of acetone and ethanol extracts of Searsia lancea, Indigofera frutescens, Erythrina caffra and Antidesma venosum were determined against the bacterial isolates using a serial microdilution assay, and cytotoxicity was also investigated. The results showed that 82.14% of the clinical isolates tested were resistant to at least one antimicrobial agent used, and 52.17% of the antibiotic resistant isolates were multidrug resistant. All plant extracts had antibacterial activity against all the bacterial isolates, but S. lancea demonstrated higher efficacy compared to other plants. The MIC values ranged from 0.01 to 2.50 mg/mL, with the lowest range obtained with the acetone extract of S. lancea (0.01 to 0.57 mg/mL). Furthermore, the extracts were relatively non-cytotoxic to bovine dermis and Vero cells, with the highest mean selectivity index value of 25.70 recorded with S. lancea. This study highlights the growing concern of AMR in livestock management, and demonstrates the promising therapeutic potential of the selected plant species, particularly S. lancea, in treating bovine mastitis. Further exploration of S. lancea is recommended to develop novel alternative or complementary formulations for mastitis management.

Preliminary studies on in vitro antioxidant and retardation of essential carbohydrate hydrolysing enzymes by some indigenous South African medicinal plants

Preliminary studies on in vitro antioxidant and retardation of essential carbohydrate hydrolysing enzymes by some indigenous South African medicinal plants

Cyclopia extracts act as selective estrogen receptor subtype downregulators in estrogen receptor positive breast cancer cell lines: Comparison to standard of care breast cancer endocrine therapies and a selective estrogen receptor agonist and antagonist.

Breast cancer is the most diagnosed type of cancer amongst women in economically developing countries and globally. Most breast cancers express estrogen receptor alpha (ERα) and are categorized as positive (ER+) breast cancer. Endocrine therapies such as, selective estrogen receptor modulators (SERMs), aromatase inhibitors (AIs), and selective estrogen receptor downregulators (SERDs) are used to treat ER+ breast cancer. However, despite their effectiveness, severe side-effects and resistance are associated with these endocrine therapies. Thus, it would be highly beneficial to develop breast cancer drugs that are as effective as current therapies, but less toxic with fewer side effects, and less likely to induce resistance. Extracts of Cyclopia species, an indigenous South African fynbos plant, have been shown to possess phenolic compounds that exhibit phytoestrogenic and chemopreventive activities against breast cancer development and progression. In the current study, three well characterized Cyclopia extracts, SM6Met, cup of tea (CoT) and P104, were examined for their abilities to modulate the levels of the estrogen receptor subtypes, estrogen receptor alpha and estrogen receptor beta (ERβ), which have been recognized as crucial to breast cancer prognosis and treatment. We showed that the Cyclopia subternata Vogel (C. subternata Vogel) extracts, SM6Met and cup of tea, but not the C. genistoides extract, P104, reduced estrogen receptor alpha protein levels while elevating estrogen receptor beta protein levels, thereby reducing the ERα:ERβ ratio in a similar manner as standard of care breast cancer endocrine therapies such as fulvestrant (selective estrogen receptor downregulator) and 4-hydroxytamoxifen (elective estrogen receptor modulator). Estrogen receptor alpha expression enhances the proliferation of breast cancer cells while estrogen receptor beta inhibits the proliferative activities of estrogen receptor alpha. We also showed that in terms of the molecular mechanisms involved all the Cyclopia extracts regulated estrogen receptor alpha and estrogen receptor beta protein levels through both transcriptional and translational, and proteasomal degradation mechanisms. Therefore, from our findings, we proffer that the C. subternata Vogel extracts, SM6Met and cup of tea, but not the C. genistoides extract, P104, selectively modulate estrogen receptor subtypes levels in a manner that generally supports inhibition of breast cancer proliferation, thereby demonstrating attributes that could be explored as potential therapeutic agents for breast cancer.

Propagation of Medicinal Plants for Sustainable Livelihoods, Economic Development, and Biodiversity Conservation in South Africa.

South Africa is blessed with vast plant resources and unique vegetation types. Indigenous South African medicinal plants have been well-harnessed to generate income in rural communities. Many of these plants have been processed into natural products to heal a variety of diseases, making them valuable export commodities. South Africa has one of the most effective bio-conservation policies in Africa, which has protected the South African indigenous medicinal vegetation. However, there is a strong link between government policies for biodiversity conservation, the propagation of medicinal plants as a source of livelihood, and the development of propagation techniques by research scientists. Tertiary institutions nationwide have played a crucial role in the development of effective propagation protocols for valuable South African medicinal plants. The government-restricted harvest policies have also helped to nudge natural product companies and medicinal plant marketers to embrace the cultivated plants for their medicinal uses, and thus have helped support the South African economy and biodiversity conservation. Propagation methods used for the cultivation of the relevant medicinal plants vary according to plant family and vegetation type, among others. Plants from the Cape areas, such as the Karoo, are often resuscitated after bushfires, and propagation protocols mimicking these events have been established through seed propagation protocols with controlled temperatures and other conditions, to establish seedlings of such plants. Thus, this review highlights the role of the propagation of highly utilized and traded medicinal plants in the South African traditional medicinal system. Some valuable medicinal plants that sustain livelihoods and are highly sought-after as export raw materials are discussed. The effect of South African bio-conservation registration on the propagation of these plants and the roles of the communities and other stakeholders in the development of propagation protocols for highly utilized and endangered medicinal plants are also covered. The role of various propagation methods on the bioactive compounds' composition of medicinal plants and issues of quality assurance are addressed. The available literature, media online news, newspapers, and other resources, such as published books and manuals, were scrutinized for information.

Green Nanotechnology as an innovative drug delivery approach for Typha capensis and Naringenin—New class of phytochemical embedded biocompatible gold nanoparticles in prostate cancer therapy

Naringenin, a flavone with a growing body of evidence as an anti-cancer agent, is found in Typha capensis, an indigenous South African plant commonly used in traditional medicine. However, despite favourable in vitro results, clinical usage of naringenin remains restricted due to notoriously poor oral bioavailability, rapid metabolism and poor tumour site availability. This study aimed to investigate a simple, easily reproduced, reliable and effective drug delivery method of mitigating these issues using green nanotechnology principles, and assess their biomedical applications in the treatment of prostate cancer. Gold nanoparticles (AuNPs) were synthesized using green nanotechnology principles and characterized by spectrophotometry, dynamic light scattering, zeta potential, transmission electron microscopy, and Folin-ciocalteu phenol assay. Effects on LNCaP and PC-3 cell viability were evaluated using the MTT assay. A significant (P < 0.0001, P = 0.0003, P = 0.0002) reduction in cell viability was observed for S1-AuNPs, S2-AuNPs and Ng-AuNPs, respectively, in PC3 cells. The extracts, naringenin, and subsequent AuNPs yielded comparable levels of toxicity toward the LNCaP cells. This study reports the first successful synthesis of self-stabilized AuNPs from naringenin in isolation and, most importantly, the application of these novel particles as an effective drug delivery tool. The biomedical applications of this novel formulation and drug delivery approach is expected to aid effective delivery of anticancer therapeutics, in this case naringenin, and thus expand the realms of the treatment of prostate cancer.

Aspalathin-rich green rooibos tea in combination with glyburide and atorvastatin enhances lipid metabolism in a db/db mouse model.

Rooibos (Aspalathus linearis), an indigenous South African plant and its major flavonoid, aspalathin, exhibited positive effects on glycemia and dyslipidemia in animal studies. Limited evidence exists on the effects of rooibos extract taken in combination with oral hypoglycemic and lipid-lowering medications. This study investigated the combined effects of a pharmaceutical grade aspalathin-rich green rooibos extract (GRT) with the sulfonylurea, glyburide, and atorvastatin in a type 2 diabetic (db/db) mouse model. Six-week-old male db/db mice and their nondiabetic lean db+ littermates were divided into 8 experimental groups (n=6/group). Db/db mice were treated orally with glyburide (5 mg/kg bodyweight), atorvastatin (80 mg/kg bodyweight) and GRT (100 mg/kg bodyweight) as mono- and combination therapies respectively, for 5 weeks. An intraperitoneal glucose tolerance test was conducted at 3 weeks of treatment. Serum was collected for lipid analyses and liver tissues for histological examination and gene expression. A significant increase in the fasting plasma glucose (FPG) of the db/db mice compared to their lean counterparts (from 7.98 ± 0.83 to 26.44 ± 1.84, p < 0.0001) was observed. Atorvastatin reduced cholesterol (from 4.00 ± 0.12 to 2.93 ± 0.13, p < 0.05) and triglyceride levels (from 2.77 ± 0.50 to 1.48 ± 0.23, p < 0.05). In db/db mice, the hypotriglyceridemic effect of atorvastatin was enhanced when combined with both GRT and glyburide (from 2.77 ± 0.50 to 1.73 ± 0.35, p = 0.0002). Glyburide reduced the severity and pattern of steatotic lipid droplet accumulation from a mediovesicular type across all lobular areas, whilst combining GRT with glyburide reduced the abundance and severity of lipid droplet accumulation in the centri- and mediolobular areas. The combination of GRT, glyburide and atorvastatin reduced the abundance and severity of lipid accumulation and the intensity score compared to the administered drugs alone. The addition of either GRT or glyburide in combination with atorvastatin had no effect on blood glucose or lipid profiles, but significantly reduced lipid droplet accumulation.

Anti-Biofilm, Antibacterial, and Anti-Quorum Sensing Activities of Selected South African Plants Traditionally Used to Treat Diarrhoea.

The development of resistance of microorganisms to conventional antibiotics is a major global health concern; hence, there is an increasing interest in medicinal plants as a therapeutic option. This study aimed to evaluate the antibacterial, anti-biofilm, and anti-quorum activities of crude extracts prepared using various solvents of nine indigenous South African plants used locally for the treatment of diarrhoea. The minimum inhibitory concentration (MIC) was determined using the broth microdilution method and the crystal violet assay was used to test the anti-biofilm activity of the extracts against a panel of bacteria. Anti-quorum sensing activity of the extracts was assessed via inhibition of violacein production in Chromobacterium violaceum ATCC 12472. Preliminary screening of extracts against E. coli ATCC 25922 revealed that the acetone extracts had significant activity, with MIC values ranging from 0.04 to 0.63 mg/mL. Further screening against a panel of bacterial pathogens showed that the acetone extract of Bauhinia bowkeri was the most active with MIC of 0.01 mg/mL against Salmonella enteritidis, followed by Searsia lancea with MIC of 0.03 mg/mL against Bacillus cereus. All the plant extracts prevented the attachment of biofilms by more than 50% against at least one of the tested bacteria. However, only the mature biofilm of B. cereus was susceptible to the extracts, with 98.22% eradication by Searsia pendulina extract. The minimum quorum sensing inhibitory concentration of the extracts ranged from 0.08 to 0.32 mg/mL with S. lancea having the most significant activity. The extract of S. lancea had the best violacein production inhibitory activity with IC50 value of 0.17 mg/mL. Overall, the results obtained indicate that acetone extracts of S. leptodictya, S. lancea, S. batophylla, S. pendulina, B. galpinii, and B. bowkeri possess antibacterial and anti-biofilm activities and can modulate quorum sensing through the inhibition of violacein production. Therefore, these results signify the potential of the selected plant extracts in treating diarrhoea through inhibition of bacterial growth, biofilm formation inhibition, and quorum sensing antagonism, supporting their medicinal use.

In vitro antioxidant and cytotoxicity activities of selected indigenous South African medicinal plants

Background: Medicinal plants are regarded as a large source of phytochemicals that may have anticancer properties. This could lead to the development of innovative drugs or alternative therapy against cancer.&#x0D; Objective: This study was designed to determine the antioxidant and cytotoxicity effect of 5 selected indigenous South African medicinal plants namely; Bulbine frutescens, Bulbine natalensis, Chlorophytum comosum, Kniphofia uvaria, and Tulbaghia violacea.&#x0D; Method: Phytochemical extracts namely; methanol, 50%, 100% ethanol, and water extracts were prepared from the root and shoot of the plants. The antioxidant effect of methanol extracts of the plant materials was performed using a DPPH assay. A preliminary cytotoxicity screening of the phytochemical extracts in the human colon (Caco-2), cervical (HeLa), and hepatocellular (HepG2) cell lines were determined followed by the half-maximal inhibitory concentration (IC50) using MTT assay.&#x0D; Result: The methanol root extract of B. natalensis and B. frutescens (33.20% and 26.33% respectively) and shoot extract of K. uvaria (17.10%) showed the highest antioxidant. Out of the 5 plants, only 100% ethanol extract of C. comosum, K. uvaria, and T. violacea caused more than 80% cytotoxicity in HepG2 and Caco-2 cell lines. The shoot of B. frutescens (10.43 μg/ml), K. uvaria (23.0 μg/ml), and root of C. comosum (23.77 μg/ml) were the most active with the highest cytotoxicity.&#x0D; Conclusion: C. comosum, K. uvaria, and T. violacea possess significant cytotoxicity that is promising in developing alternative drugs against colon and liver cancers. Our results provided new pieces of evidence for antioxidant and cytotoxic activities of these plants which could be useful for developing new anticancer therapies.&#x0D; Keywords: In vitro antioxidant; cytotoxicity activities; South African medicinal plants; C. comosum, K. uvaria, T. violacea.

Efficiencies of indigenous South African plant biofilters for urban stormwater runoff water quality improvement with a focus on nutrients and metals

Abstract In South Africa, urban activities contribute high levels of pollution to rivers and groundwater via stormwater runoff. In reducing urban stormwater loads of engineered plant biofiltration, an effective and self-sustaining component of green infrastructure is a treatment option. The country's extensive natural biodiversity offers untapped potential of indigenous species' use in plant biofilters. This paper presents the findings of a plant biofilter column experiment, which investigated the performance of nine indigenous plant species under varied urban stormwater pollutant load strengths. Average significant loads of dissolved Cd (&amp;gt;98%), Cu (&amp;gt;84%), Pb (&amp;gt;99%) and Zn (&amp;gt;95%), as well as NH3-N (&amp;gt;93%), were removed by the plant biofilters, whereas the removal of -N (−37 to 79%) and -P (−81 to 63%) was more variable. Biofilters equipped with indigenous plant species were on average at least 11% more efficient than unvegetated soil in the removal of urban nutrient and metal pollutants. Over time, planted biofilters improved nutrient and metal removal efficiencies. The results support the inclusion of indigenous plants in biofilters within urban stormwater green infrastructure initiatives. Further research to inform plant biofilter design practicalities and assess plant biofilter performance in the field is warranted.

Preliminary study on in vitro shoot culture of Hibiscus coddii subsp. barnardii, an indigenous South African flowering plant

Abstract In vivo and in vitro grown plants of Hibiscus coddii subsp. barnardii were used as explant source for establishment of in vitro cultures. Nodal shoot explants derived from in vivo grown plants, both naturally and under controlled environmental conditions, showed high sensitivity to the surface disinfection treatment and poor survival in in vitro culture. In vitro grown seedlings proved successful as aseptic source of apical and basal shoot explants to establish contamination-free in vitro cultures. Sprouting of axillary buds was observed on 90% of apical shoot explants after four weeks of culture on full strength, plant growth regulator (PGR)-free Murashige and Skoog (MS) medium. However, further proliferation of short shoots, limited to the bud sprout at the explant base, occurred on only 50% of these explants. In contrast, all basal shoot explants attained 3-5 single primary axillary shoots (30-40 mm in length) while a clump of short (5-10 mm) shoots also formed at the base in 60% of these explants. In both explant types, addition of 0.25-1 mg L-1 6-Benzylaminopurine (BAP) to the MS medium resulted in a low frequency (10%-60%) of explants with short shoots (5-10 mm) that showed no further elongation. Moreover, explants cultured in the presence of BAP showed a high frequency of callus formation (up to 90%) and low survival (20%-60%). A lower frequency of callus formation (30%-40%) and higher survival (90%-100%) of both explant types occurred on BAP-free medium. Further subculturing of primary and secondary axillary shoots onto fresh MS medium (with and without BAP) did not improve shoot multiplication. Regenerated plantlets from PGR-free MS medium were successfully acclimatized and hardened-off.

Abstract 2843: The effects of extracts of the indigenous South African plant, Tulbaghia violacea, on triple negative breast cancer cells

Abstract Background: Up to 20% of all breast cancer cases can be defined as triple-negative breast cancers (TNBC). TNBC is defined by the absence of the expression of oestrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor 2 (HER2). TNBC is an aggressive cancer that in South Africa, primarily affects younger black females. Due to the lack of hormone receptors and current targeted therapies are ineffective. In South Africa, many people rely on traditional medicine to treat various ailments. However, the effectiveness of these treatments needs to be scientifically verified. Aim: The aim of this study was to evaluate the in vitro responses of TNBC cancer cell lines to treatment with extracts from the indigenous South African medicinal plant, Tulbhaghia violacea. Methods: To achieve this the TNBC cell line, MDA-MB-231, was treated with both water and methanol soluble extracts from the leaves. The IC50 values for the extract was determined using Real Time Cell Analysis in conjunction with alamarBlue cytotoxicity assay. The effect of the plant extract on cell migration was determined using the scratch assay. The chemical composition of the extract was determined using Fourier Transformer Infrared (FTIR) Spectrophotometry. Results: Of the two extracts the water soluble T. violacea extract had the lowest IC50 value (314 μg/ml), while the methanol soluble extract showed much lower cytotoxic activity with a higher IC50 value (780 μg/ml). The T. violacea water extract strongly affected the migration of the TNBC cell line, with concentrations slightly lower than the IC50 value (300 μg/ml) preventing cell migration completely and lower concentrations delaying migration by up to 13 hours. This was similar to the effects observed when the cells were treated with the positive control (5-Fluorouracil). The FTIR spectrophotometry analysis of the T. violacea water extract revealed that this extract is a mixture of phytochemicals with various functional groups including alkyl, methyl, nitro, sulphur derivative and amine groups. Discussion: The water soluble extract from T. violacea leaves showed cytotoxic effects against MDA-MB-231 TNBC cells and also inhibited the ability of these cells to migrate. Since migration is involved in invasion and metastasis this indicates that one or more of the chemical constituents found within the water soluble extract may serve as a lead compound for the development of new drugs to treat TNBC. The classes of chemical constituents we identified in the water soluble extract is consistent with compounds known to be present within T. violacea. Further characterization of this extract is under way and we are in the process of isolating individual active compounds from this extract and performing RNASeq experiments to ascertain aberrant molecular pathways including splicing events that this extract targets. Citation Format: Zodwa Dlamini, Mohamed Alouna, Rodney Hull, Clement Penny. The effects of extracts of the indigenous South African plant, Tulbaghia violacea, on triple negative breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2843.

Design and operation of plant microbial fuel cells using municipal sludge

Plant microbial fuel cells (PMFC) can simultaneously treat wastewater and generate bioelectricity. In the context of municipal wastewater, most PMFC studies have focused on settled sewage instead of the sludge produced in the treatment process. This research focused on designing and operating a PMFC that used thickened waste activated sludge (WAS) and soil as a substrate. Granular activated carbon (GAC) was used as the anode because of its large surface area, bio-compatibility, ability to conduct electricity and relatively low price. Carbon paper coated with 0.4 mg/cm2 Pt was used as the cathode. The PMFC systems were operated using two indigenous South African plant species, namely, Wachendorfia thyrsiflora and Cyperus papyrus nanus. During the operation, the importance of ensuring the cathode stayed attached to the cell, having a wet cell and the right selection of the resistor connected was noted. When comparing the power output of the plant species, the W. thyrsiflora produced the highest, 1036 ± 59 mW/m3 followed by C. papyrus with 510 ± 92 mW/m3 and the lowest was measured in the control (no plant), 392 ± 67 mW/m3. However, the W. thyrsiflora did not survive the duration of the experiment and died. The most likely reason for plant death was high nutrient load. The C. papyrus survived the duration of the experiment and hence this plant species is recommended for future PMFC applications that use WAS as a substrate. This work provides a novel treatment method for WAS that is also capable of producing power.

Elemental analysis of the edible fruit of Carpobrotus dimidiatus (from Kwazulu-Natal, South Africa) and the influence of soil quality on its elemental uptake

Carpobrotus dimidiatus is an indigenous South African medicinal plant species from the Aizoaceae family that bears edible fruit that is consumed for nutritional value. In this study, the elemental distribution in C. dimidiatus fruit and growth soil from fifteen sites in KwaZulu-Natal (South Africa) was determined along with soil pH, soil organic matter and cation exchange capacity, to assess for nutritional value and the effect of soil quality on elemental uptake. The results showed elemental concentrations in fruit to be in decreasing order of Ca (6235–32755 mg kg−1) > Mg (2250–5262 mg kg−1) > Fe > Mn > Zn (20.9–50.6 mg kg−1) > Cu (3.83–20.6 mg kg−1) > Pb > Cr > Cd > As ∼ Co ∼ Ni ∼ Se and no potential health risk due to metal toxicity from average consumption. For sites that had high levels of Cd and Pb, bioaccumulation occurred from atmospheric deposition. Concentrations of elements in soil were found to be in decreasing order of Fe (1059–63747 mg kg−1) > Ca (1048–41475 mg kg−1) > Mg > Mn (9.76–174 mg kg−1) > Cr (1.55–135 mg kg−1) > Zn (0.76–58.2 mg kg−1) > Se > Cu > Ni > Pb > Co > As ∼ Cd with no evidence of heavy metal contamination. This study revealed that the plant inherently controlled uptake of essential elements according to physiological needs and that the concentrations of essential elements in the fruit could contribute positively to the diet.

Experimental validation and computational modeling of anti-influenza effects of quercetin-3-O-\u03b1-L-rhamnopyranoside from indigenous south African medicinal plant Rapanea melanophloeos

BackgroundInfluenza A virus (IAV) is still a major health threat. The clinical manifestations of this infection are related to immune dysregulation, which causes morbidity and mortality. The usage of traditional medication with immunomodulatory properties against influenza infection has been increased recently. Our previous study showed antiviral activity of quercetin-3-O-α-L-rhamnopyranoside (Q3R) isolated from Rapanea melanophloeos (RM) (L.) Mez (family Myrsinaceae) against H1N1 (A/PR/8/34) infection. This study aimed to confirm the wider range of immunomodulatory effect of Q3R on selective pro- and anti-inflammatory cytokines against IAV in vitro, to evaluate the effect of Q3R on apoptosis pathway in combination with H1N1, also to assess the physical interaction of Q3R with virus glycoproteins and RhoA protein using computational docking.MethodsMDCK cells were exposed to Q3R and 100CCID50/100 μl of H1N1 in combined treatments (co-, pre- and post-penetration treatments). The treatments were tested for the cytokines evaluation at RNA and protein levels by qPCR and ELISA, respectively. In another set of treatment, apoptosis was examined by detecting RhoA GTPase protein and caspase-3 activity. Molecular docking was used as a tool for evaluation of the potential anti-influenza activity of Q3R.ResultsThe expressions of cytokines in both genome and protein levels were significantly affected by Q3R treatment. It was shown that Q3R was much more effective against influenza when it was applied in co-penetration treatment. Q3R in combination with H1N1 increased caspase-3 activity while decreasing RhoA activation. The molecular docking results showed strong binding ability of Q3R with M2 transmembrane, Neuraminidase of 2009 pandemic H1N1, N1 and H1 of PR/8/1934 and Human RhoA proteins, with docking energy of − 10.81, − 10.47, − 9.52, − 9.24 and − 8.78 Kcal/mol, respectively.ConclusionsQuercetin-3-O-α-L-rhamnopyranoside from RM was significantly effective against influenza infection by immunomodulatory properties, affecting the apoptosis pathway and binding ability to viral receptors M2 transmembrane and Neuraminidase of 2009 pandemic H1N1 and human RhoA cellular protein. Further research will focus on detecting the detailed specific mechanism of Q3R in virus-host interactions.

Laboratory method design for investigating the phytoremediation of polluted water

The performance of plants to remove, remediate or immobilise environmental contaminants in a growth matrix through natural biological, chemical or physical activities was studied in a laboratory phytoremediation system. This study aimed to develop a novel phytoremediation system capable of investigating the remediation of agricultural pollutants by individual and multiple plant species. The designed system analysed community phytoremediation by uniquely implementing multiple plant species within the same growth silo, with indigenous and alien assemblages compared to establish community performance, highlighting the importance of biodiversity in plant assemblages. The constructed system successfully analysed the phytoremediatory capabilities of plant species within the critically endangered Renosterveld vegetation type, with unvegetated soil controls included to illustrate the pollutant removal efficiency of plants only. Growth silos were constructed from PVC piping and irrigated with drippers from a submersible pump. Eighteen different plant species were included in the experiment, i.e., 14 indigenous species, 3 invasive alien plant (IAP) species, and Palmiet. Five agricultural pollutant parameters were analysed, i.e., for fertilizers NH3-N, NO3--N and PO43--P and for herbicide contamination using two glyphosate concentrations. The growth silos and unvegetated soil control were irrigated using a pollutant–municipal water solution at 3-day intervals. The multiple plants per silo design approach seeks to contribute to the limited literature pertaining heterogeneity importance, by comparing the pollutant removal performance of plant assemblages. Community comparison further investigated the biofilter implementation potential of indigenous South African plants as an alternative to their more invasive alien counterparts, adding to the knowledge base of plant-based phytoremediation by indigenous South African plant species. The laboratory phytoremediation system successfully measured the agricultural pollutant removal performance of individual plants and vegetative communities, with soil remediation influence acknowledged. The proposed system is a simple and inexpensive method for obtaining the plant-based biofiltration efficiency of individual and multiple plant species.

Investigating the performance of constructed wetland microbial fuel cells using three indigenous South African wetland plants

Constructed wetland microbial fuel cells (CW-MFC) can be used to treat wastewater while also generating bio-electricity. Most research on CW-MFCs have focused on cell configuration rather than the influence different wetland plants have on bio-electricity production.In this study, three different indigenous wetland plants were investigated: Cyperus prolifer, Wachendorfia thyrsiflora, and Phragmites australis. Bio-electricity production was assessed in terms of maximum power density and voltage variation. The highest power density and voltage was obtained from the C. prolifer plant species (229 ± 52 mW/m3; 510 mV). The removal efficiency of chemical oxygen demand was 97 ± 1% for C. prolifer, which was higher than W. thyrsiflora (94 ± 1%), P. australis (94 ± 1%) and the control (unplanted) system (90 ± 2%). Phosphorus removal was measured in terms of orthophosphate removal efficiency. The C. prolifer plant species achieved higher orthophosphate removal efficiency (98 ± 0%) than the control (72 ± 7%), W. thyrsiflora (58 ± 6%) and P. australis (81 ± 4%). It was determined that a high root specific area and biomass were advantageous to power production. It was also found that rapid acclimatisation to the wastewater was an important factor for generating power.From this study, it was determined that C. prolifer was the most suitable wetland plant in terms of bio-electricity, organic matter, ammonia and phosphate removal among the investigated plant species. Hence, in the design of a CW-MFC it would be advisable to use C. prolifer to simultaneously treat wastewater and produce bio-electricity.

Bioactive Compound Produced by Endophytic Fungi Isolated From Pelargonium sidoides Against Selected Bacteria of Clinical Importance

Endophytic fungi have the ability to live inside the host plant tissues without causing neither symptoms of diseases/or harm. Opportunistic infections are accountable for majority of the outbreaks, thereby putting a burden on the health system. To investigate and characterize the bioactive compounds for the control of bacteria of clinical importance, extracts from endophytic fungi were isolated from indigenous South African medicinal plants. Extracts from endophytic fungi were isolated from 133 fungal strains and screened against Gram positive and negative bacteria namely Bacillus cereus, Escherichia coli, Enterococcus faecium, and E. gallinarum using disk diffusion. Furthermore, gas chromatography–mass spectrometry was performed to identify the bioactive compounds. Sixteen out of one hundred and thirty-three (12%) fungi extracts exhibited antibacterial properties against some of the selected bacteria. E. coli was found to be the most susceptible in contrast to E. faecium and E. gallinarum which were the most resistant. The isolate MHE 68, identified as Alternaria sp. displayed the greater spectrum of antibacterial activities by controlling selected clinical bacteria strains including resistant E. faecium and E. gallinarum. The chemical analysis of the extract from MHE 68 indicated that linoleic acid (9,12-octadecadienoic acid (Z,Z)) and cyclodecasiloxane could be accountable for the antibacterial activity. This is the first study conducted on the secondary metabolites produced by endophytic fungal strains isolated from the Pelargonium sidoides DC. possessing antibacterial properties.

ANTI-PROLIFERATIVE AND ANTIOXIDANT ACTIVITY OF FOUR INDIGENOUS SOUTH AFRICAN PLANTS.

Background: Cancer is a major cause of death worldwide. Limitations of current cancer therapies necessitate the search for new anticancer drugs. Plants represent an immeasurable source of bioactive compounds for drug discovery. The objective of this study was to assess the anti-proliferative and antioxidant potential of four indigenous South African plants commonly used in traditional medicine. Materials and Methods: The anti-proliferative activity of the plant extracts were assessed by the 2,3-Bis-(2-Methoxy-4- Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide (XTT) assay on A431; HaCat; HeLa; MCF-7 and UCT-Mel 1 cells and sulforhodamine-B (SRB) assay on HCT-116 and HCT-15 cell lines. Antioxidant activity was determined using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO) and superoxide scavenging assays. Results: Three of the plant extracts (Combretum mollefruit, Euclea crispa subsp. crispa leaves and stems and Sideroxylon inerme leaves and stems showed anti-proliferative activity on the A431 cells with IC50values ranging between 26.9 - 46.7 μg/ml. The Euclea crispa subsp. crispa extract also showed anti-proliferative activity on the MCF-7 cell line (45.7 μg/ml). All of the plant extracts (Combretum molle leaves and fruit, Euclea crispa subsp. crispa leaves and stems, Sideroxylon inerme leaves and stems and Terminalia prunioides leaves and stems) showed DPPH scavenging activity with IC50 values ranging from 1.8 μg/ml to 11.5 μg/ml. Conclusion: These results indicate that the active extracts of Combretum molle, Euclea crispa subsp. Crispa and Sideroxylon inerme warrants further investigation to determine the mechanism of anti-proliferative activity against cancerous cells. These plant extracts also show potential for further evaluation in the prevention and treatment of cancer.