Kigelia Research Articles

Anti-diabetic efficacy and selective inhibition of methyl glyoxal, intervention with biogenic Zinc oxide nanoparticle

Non-enzymatic glycation of biomolecules results in advanced glycation end products (AGEs), which are responsible for secondary complications in diabetes. Inhibiting methyl glyoxal (MGO) induced advanced glycation end product (AGE) formation is the only way to alleviate diabetic complications. This study aimed to look into the abilities of herbal extract Kigelia africana and K. africana synthesized zinc oxide nanoparticles (ZnONPs) to inhibit the emergence of MG-derived AGEs. The study intended to determine antioxidant and AGE inhibition of the plant extract and ZnONPs. ZnONPs were tested for the efficiency of anti-diabetic activity in streptozotocin-induced diabetic Wister rats. We discovered that the MGO-trapping effects on the prevention of AGE production were mediated by the downregulation of the amplification of MGO-trapping impacts on the hypoglycemic and antihyperlipidemic mechanisms of ZnONPs. According to histological findings, the treatment with ZnONPs also successfully lowers inflammation in the hepatic and renal tissues. Overall, future mechanistic research could establish ZnONPs potential anti-diabetic properties.

Phytochemical and isolated compound speciocide from Kigelia africana fruit

Phytochemicals produced by herbs and medicinal plants have a variety of therapeutic uses. They also help the plant's colour and organoleptic characteristics. Due to their absence of adverse effects, these phytochemicals are used in advanced medical systems to efficiently treat ailments. Because Kigelia Africana contains phytoconstituents, the plant has gained significant scientific attention for its wide range of pharmacological properties. It has been examined and shown to have a number of compounds that treat cancer, psoriasis, dysentery, inflammations, and bacterial infections. The goal of the current investigation was to identify and separate the chemical components found in the fruit extracts of Kigelia africana (Lam.) Benth. Preliminary phytochemical screening performed on n-hexane, chloroform, ethyl acetate, ethanol and aqueous extracts showed the presence of alkaloids, glycosides, phenols, flavonoids etc. The qualitative estimation of the phytoconstituents revealed the presence of total phenols, total flavonoids, total saponins and glycosides as 9.38, 2.64, 3.12 and 6.45 %w/w respectively in the ethanol extract. The ethanol extract was subjected to TLC and coloumn chromatography which resulted in 4 fractions out of which fraction F4 was in significant quantity. It was analyzed using HPTLC that showed the presence of one isolated molecule.

Effects of Combined Garcinia kola and Kigelia africana on Insulin and Paraoxonase 1 (PON1) Levels in Type 2 Diabetic Rats.

Individual extracts of Garcinia kola and Kigelia africana have been shown to have therapeutic effects against a variety of variables linked to the development of diabetes mellitus. However, there is still a lack of information about the combined effects of these extracts on Insulin and Paraoxonase 1 (PON-1) in Streptozotocin-Nicotinamide-induced type-2 diabetic Wistar rats. Forty-two young male rats (180-200g) were randomly divided into six groups (n = 7/group). Diabetes was intraperitoneally induced with 110 mg/kg of nicotinamide constituted in distilled water and fifteen minutes later with 65 mg/kg of streptozocin freshly prepared in 0.1M citrate buffer (pH of 4.5) and treated for six weeks as follows: the control rats received either 0.9% normal saline (NS) or 250 mg/kg extract by gavage. The remaining animals were diabetes induced and subsequently treated with either NS, graded doses of the extract (250 mg/kg and 500 mg/kg), or 5 mg/kg Glibenclamide + 100mg/kg Metformin. Gas chromatography-mass spectrometry (GCMS) of the combined extracts was also analyzed to identify the bioactive compounds present in it. Insulin, PON-1 levels, lipid profiles, and atherogenic index were assessed. Our findings show that Insulin and PON-1 levels in the plasma of diabetic rats treated with the combined extracts were significantly increased when compared to the control rats. Moreover, the GCMS of the extract shows the presence of both monounsaturated (oleic acid) and polyunsaturated (linoleic acid) fatty acids. The current findings suggest that the extract may help improve glucose homeostasis and prevent atherosclerosis through the established mechanism of the identified bioactive compounds.

Potential seed dispersal mechanism of Kigelia africana (Lam.) Benth. in an urban habitat

ABSTRACT Kigelia africana is known to exhibit megafaunal syndrome. Many mega faunal taxa having become extinct with time, the species seems to have adapted to its changing environment by ensuring the dispersal of its seeds by alternative dispersers. The present investigation reports the mechanism of seed dispersal adopted by individuals of K. africana grown in India, outside the species natural environment. The massive – ~2.0 kg – indehiscent and unattractive fruits retain the wingless seeds. Of more than 300 seeds present in a fruit in average, approximately 92% remained viable at maturity, and the viability decreased over time after 1 year. We observed that numerous termites (Coptotermes formosanus) initiated the disintegration of the fallen fruits particularly during monsoon. Three-striped squirrels (Funambulus palmarum), classified as scatter hoarding rodents, then accessed these fruits and their seeds, and actively carried about 48% seeds with broken coats to a distance of 40 m away from the mother trees. The coordinated activity of these two dynamic vectors ensured successful seed dispersal in K. africana at the study site, suggesting that the species may have developed a way to adapt to its new environment.

Kigelia africana inhibits proliferation and induces cell death in stage 4 Neuroblastoma cell lines

Neuroblastoma (NB) is one of the most common solid pediatric tumors and especially high-risk NBs still account for about 12–15% of cancer related deaths in children. Kigelia africana (KA) is a plant used in traditional African medicine which has already shown its anti-cancer potential in several in vitro and in vivo studies. The aim of this study is to evaluate the effect of KA fruit extract on stage 4 high-risk NB cells. Therefore, NB cell lines with and without MYCN amplification and non-neoplastic cells were treated with KA fruit extract at different concentrations. The effect of KA on cell viability and apoptosis rate were assessed by bioluminescence-/fluorescence-based assays. Several proteins involved in survival, tumor growth, inflammation and metastasis were detected via western blot and immunofluorescence. Secreted cytokines were detected via ELISA. Phytochemical composition of the extract was analyzed by liquid chromatography with tandem mass spectrometry (LC/MS/MS). Our group demonstrates a dose- and time-dependent selective cytotoxic effect of KA fruit extract on NB, especially in MYCN non-amplified tumor cells, by inhibiting cell proliferation and inducing cell death. Western blot and immunofluorescence results demonstrate a regulation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), disialoganglioside GD2 and epidermal growth factor receptor (EGFR) in KA-treated tumor cells. Our results evidence striking anti-cancer properties of KA fruit and pave the way for further surveys on the therapeutic properties and mechanisms of action in NB.

INSECTICIDAL AND ANTIFEEDANT ACTIVITIES OF AQUEOUS LEAF EXTRACTS AGAINST Epilachna vigintioctopunctata (COCCINELLIDAE: COLEOPTERA) UNDER LABORATORY CONDITIONS

The aqueous leaf extracts of different plant such as Cryptostegia grandiflora, Mansoa alliacea, Allamanda cathartica, Allamanda blanchetti and Xanthium strumarium and leaves of tree species such as Kigelia pinnata, Bauhinia Purpurea, Drypetes roxburghi, Conocarpus lancifolius and Polyalthia longifolia were studied against the grubs of Epilachna vigintioctopunctata at various concentrations under laboratory conditions. Among the plant tested, the maximum insecticidal activity and leaf area protection was noticed in Xanthium strumarium 93.33% and 91.62% at 7% concentration with an estimated LC50 of 1.11% followed by D. roxburghii (80.00% & 85.55%) and C. lancifolius (73.33% and 82.90%) respectively. The minimum per cent mortality was noticed in the treatment, Mansoa alliacea 7% with 40.00% and its antifeedancy were 50.97%. Results revealed that both the antifeedancy and mortality was increased with increasing in concentration of the plant extracts.

Oxygen Production and Carbon Capturing Capacity of Various Tree Species in Coimbatore City, India

Climate change, environment pollution, rapid urbanization and industrialization have been recognized as major environmental threats of the present-day scenario. These environmental issues cause severe socio-economic implications across the globe. The living space and human settlements are increasing rapidly in urban areas of India. Simultaneously the existing green cover and tree population are declining in the name of developments. Trees are considered to be one of the important assets in cities, they provide myriad benefits. Considering the importance of trees the cities and their role in reducing the pollution besides adding fresh oxygen to the atmosphere, the present investigation focused with the aim of documenting various tree species in Coimbatore city and to assess their carbon capturing and oxygen release potential. There are about 58 tree species comprising of 27 families, that have been documented and classified into four age classes. Further these tree species were subjected to total biomass, carbon stock, CO2 (eq.), net carbon sequestration and net oxygen release assessment using standard non-destructive method. Among the 58 tree species studied, Albizia lebbeck (2.745 ton tree-1year-1), Tamarindus indica (2.156 ton tree-1year-1), Parkia biglandulosa (1.921 ton tree-1year-1), Delonix regia (1.027 ton tree-1year-1), Kigelia Africana (1.009 ton tree-1year-1), Peltophorum pterocarpum (1.006 ton tree-1year-1), Ficus religiosa (0.906 ton tree-1year-1), Leucaena leucocephala (0.804 ton tree-1year -1) of net oxygen were found to release, Pterospermum acerifolium (0.827 ton tree-1year-1) and Azadirachta indica (0.804 ton tree-1year-1) were found to release high oxygen with more carbon capturing capacity.

Ethnobotanical survey of plants locally used in the control of termite pests among rural communities in northern Uganda

BackgroundTermites are the most destructive pests in many agricultural and forest plantations in Uganda. Current control of termites mostly relies on chemical pesticides. However, the adverse effects of chemical insecticides necessitate the need to search for and popularize the usage of environmentally safer options. Plants represent one of the most accessible resources available for termite control by communities in Uganda. However, limited documented information exists for their contribution in the management of except through verbal sharing. This study aimed at assessing the communities’ knowledge about plants traditionally used in controlling termites among selected communities in Apac District, northern Uganda.MethodAn ethnobotanical survey was conducted between November 2016 and February 2017 in 12 randomly selected villages in the sub counties of Apac and Ibuje of Apac District, northern Uganda. Open-ended questionnaire interviews were used to gather ethnobotanical and sociodemographic data. A total of 381 indigenous people were interviewed [male, 281 (73.8); female, 100 (26.2)]. Data were analysed using descriptive statistics and Informant Consensus Factor (ICF), and the relative frequency of citation (RFC) was determined.ResultsOverall, 70.9% of the respondents were knowledgeable about plants used for control of termites. There was a significant association between respondents’ knowledge of pesticidal plants with age and gender but not with education status. A total of 11 plant species belonging to eight families were identified to be in use for control of termites in Apac. Solanaceae, Eurphorbiaceae and Asteraceae were the most represented families with two species each, while the rest of the families had only one species mentioned. According to the relative frequency of citation (RFC), Kigelia africana (Lam.) Benth. (RFC = 0.43), Vernonia amygdalina Delile (0.18) and Tithonia diversifolia (Hemsl.) A. Gray (0.10) were the most used in the control of termites in the study area. Fruits (45.9%) and leaves (29.2%) were the most used plant parts. Squeezing, crushing and chopping of the plant materials were the most popular methods of preparation and water extract was the commonest mode of formulation of plant parts.ConclusionsThe study has shown that rural populations of the targeted localities possess indigenous knowledge on anti-termitid plants. However, screening is urgently needed to validate their bioactivity and to determine the bioactive constituents responsible for killing the invertebrates in pest management. Furthermore, simple methods for local propagation and cultivation are needed to ensure a sustainable supply of termicidal plant biomass.

Growth Performance, Carcass Traits, Muscle Fatty Acids, Intramuscular Fat, Cholesterol, and Antioxidant Status in Rabbits Supplemented with Kigelia pinnata Leaf Meal

AbstractThe effects of dietary Kigelia pinnata leaf (KPL) on growth, carcass, muscle fatty acids, antioxidant status, cholesterol, physicochemical properties, and sensory profile of Longissimus thoracis et lumburum (LTL) muscle in rabbits are investigated. Seventy‐two, 32 d old male New Zealand rabbits (684 ± 18 g) are randomly assigned to diets containing either no KPL (KPL‐0), 5% KPL (KPL‐5) or 10% KPL (KPL‐10) for eight weeks, and euthanized, and the LTL is refrigerated for 6 days. Dietary KPL does not influence growth performance and carcass cuts in rabbits. Abdominal fat is lower in KPL‐ rabbits than in the KPL‐0 rabbits. Supplemented LTL has lower intramuscular fat and cholesterol, and higher crude protein, polyphenol content, glutathione reductase, and catalase compared with the control LTL. Concentration of C18:3n‐3, C22:6n‐3, and C20:5n‐3 is higher in supplemented LTL than the control LTL. Supplemented meat has lower cook loss than the KPL‐0 meat at 24 h postmortem. The KPL‐10 meat has higher redness and lower malondialdehyde content than other meats on d 6 postmortem. Juiciness and overall acceptance of the supplemented meat are higher than that of the KPL‐0 meat. Supplementation with KPL‐10 enhances muscle n‐3 fatty acids, sensorial quality, and oxidative stability of rabbit meat.Practical Applications: Practical applications: Rabbit meat is replete in n‐6 polyunsaturated fatty acid (PUFA) but low in n‐3 PUFA, which heightens its n‐6/n‐3 ratio. Higher n‐6/n‐3 PUFA intake can pose serious health risks to consumers. This suggests a need to ameliorate the n‐3 PUFA of rabbit meat. Dietary KPL causes ≈147–184% increase in n‐3 PUFA and a 66–77% decrease in n‐6/n‐3 ratio in rabbit meat. Moreover, KPL improves sensorial quality and oxidative stability and lowers intramuscular fat and cholesterol content of rabbit meat. These results support the delivery of a healthier rabbit meat that responds to consumer demands. This study explicates the potential of KPL in ameliorating the nutritional value and sensory quality of rabbit meat.

Preliminary phytochemical and analgesic activity extract of Kigelia pinnata leaf

Kigelia pinnata Linn. (Balam Kheera) belongs to the family of Bignoniaceae and is commonly called the "sausage" tree because of its hugs fruits. The present research was conducted to investigate the analgesic activity of different extracts of leaves of Kigelia pinnata. Preliminary phytochemical investigations were performed by chemical tests. In the preliminary phytochemical test, the leaves extract showed the presence of phytosterols, alkaloids, glycosides, flavonoids, saponins, tannins, and phenolic compounds. An acute toxicity study was performed according to OECD guidelines. The analgesic activity was conducted by Hot Plate Method and Tail Immersion Test on adult Swiss albino mice. In Acute Toxicity Study, oral administration of extract was found safe at a dose of 2,000 mg/kg, p.o. and produced no signs of toxicity. The methanolic extract was found to be significant in Analgesic activity.

GREEN SYNTHESIS OF MANGANESE OXIDE NANOPARTICLES USING KIGELIA AFRICANA (LAM.) BENTH. AQUEOUS ROOT EXTRACT AND INFLUENCE ON CHICKPEA (CICER ARIETINUM LINN.) SEED GERMINATION AND PLANT GROWTH

Use of different seed priming treatments improves seed germination and thus increases plant growth and yield potential. Eco-friendly, cost-effective, simple, and effective seed treatments need to be developed for a high-consuming crop like chickpea (Cice rarietinum Lin.). In the present study, manganese oxide nanoparticles were synthesized using an aqueous extract of roots of Kigelia africana (Lam.) Benth and used as nano priming agents for chickpea seeds. The synthesized nanoparticles were found to have rod-like morphology with heterogeneous size distribution. The nanoparticle’s average size was found to be 67 nm with a metal content of 52.04 %. The sprout’s emergence was found to be high in nanometal-treated chickpea seeds than in untreated and metal treated seeds. The seedling rate after ten days of sowing was found to be high in nanoparticle-treated seeds. The nanometal treatment shows low mean germination time, high germination rate, root length and shoot length of the chickpea compared to untreated samples. The present study results demonstrates that seed priming with manganese oxide nanoparticles could enhance seed germination and growth through an eco-friendly and sustainable nanotechnological approach.

Kigelia africana fruit biofibre polysaccharide extraction and biofibre development by silane chemical treatment

Silane-treated natural cellulosic Kigelia africana fruit fibre (KAF) was experimentally established to have strong strength after removing hydrophilic materials. Silane treatment makes it compatible with hydrophobic biopolymeric materials than existing non-grafted KA fibre. In this work, the polysaccharide was extracted from the KAF and found to have all the essential compounds. KA fruit-based cellulosic fibre was extracted and treated with different concentrations of silane solution. Silane-treated (13%) KAF has a cellulose content of about 76.86%. The peak found at 1734 cm−1 shows the hemicellulose in untreated fibres, and its intensity decreased after silane treatment, as confirmed by FTIR. X-ray diffraction investigation indicated that silane-treated (5%) KAF has a crystallinity index of 70.22%. After treatment, the tensile strength of 5% silane-treated KAF shows a tensile strength of 490.77 MPa, giving more viability to biofibre reinforcement.

Investigating the Use Profile of Kigelia africana (Lam.) Benth. through Market Survey in Benin

This research focuses on Kigelia africana in Benin where it is widely used in traditional medicine but receives little attention from researchers. In addition, this species has recently been recorded as threatened in the country. The aim was to gather ethnobotanical knowledge using a printed semi-structured questionnaire to collect data from herbal medicine traders, randomly selected, through a face-to-face discussion. The survey was carried out from January to March 2020. Among 36 questioned herbal traders, 36% of respondents obtained parts of K. africana by purchase in their own markets and by travelling far (3–10 km covered). The same proportion travel very far before buying parts (more than 10 km covered). None mentioned harvesting parts from wild populations. A high proportion of informants (63%) sold fruits and stem bark whereas a relatively low proportion of them (37%) sold fruits, stem bark, and leaves. The stem bark was recorded as most in demand followed by fruits. Respondents mostly confirmed the species scarcity. This species was used to treat 13 diseases and disorders. The stem bark was the most cited in the management of stomach infections and gynecological disorders. Fruits were mainly used in magic rituals and the treatment of stomach infections. Five preparations were recorded whither 54% of traders mentioned bark decoctions and 27% highlighted infusion of fruits in water. Overall, Kigelia africana is an important plant in Beninese ethnomedicine and the harvest and trade of its different parts represent major threats. Therefore, urgent conservation tools and actions are needed.

Evaluation of the Nutritional Value, Antioxidant and Antimicrobial Compositions of Kigelia Africana Fruit

The use of plant as medicine has a long history in the treatment of various diseases. In Africa, traditional medicine is practiced and plants are exploited for the treatment of many infections and diseases. Kigelia africana is one of such plants used to prepare local tonics for improved health and growth. This research aimed to investigate and compare the yield, phytochemical presence, antioxidant and antimicrobial activities of n-hexane, ethylacetate and ethanol extracts of Kigelia africana fruit. Proximate analysis was carried out on Kigelia africana fruit. N-hexane, ethylacetate and ethanol were used to successively extract the Kigelia africana fruit. Phytochemical screenings were conducted to identify the secondary metabolites present. The DPPH (1, 1 –diphenyl-2-picrylhydrazyl) radical scavenging assay was employed to determine the radical scavenging effects of antioxidants present in the extracts. The percentage yield were 0.87, 1.65 and 8.24% for n-hexane, ethylacetate and ethanol extract respectively. The phytochemical screening revealed the presence of alkaloid, flavonoid, tannin, terpenoids, phenol, cardiac glycoside, coumarins, phlobatannins, saponin, sterols and quinone in differing amounts in the three extracts. The DPPH antioxidant scavenging assay gave IC50 value of n-hexane, ethylacetate and ethanol extract to be 3050, 60 and 29.5 µg/ml respectively. This research provided scientific evidence showing potentials of Kigelia africana fruit for use as medicine for treatment of infectious disease.

Biology, chemistry, and pharmacological activity of Kigelia africana (Bignoniaceae) and Garcinia kola (Clusiaceae) - a review.

Kigelia africana and Garcinia kola are two West African medicinal plants traditionally used to treat or alleviate various medical conditions such as skin ailments, respiratory disorders, and digestive problems. Phytochemical analyses indicated the presence of bioactive constituents, including flavonoids and phenolic acids, suggesting that the extracts of these two plants can interfere with reactive oxygen species-induced oxidative stress, inflammation, and microbial growth. This paper reviews the biochemical properties and the antioxidant, anti-inflammatory, and antibacterial activities of these two relevant West African medicinal plants.

Differential Expression of Platelet Activation Markers, CD62P and CD63, after Exposure to Breast Cancer Cells Treated with Kigelia Africana, Ximenia Caffra and Mimusops Zeyheri Seed Oils In Vitro

Cancer patients, including breast cancer patients, live in a hypercoagulable state. Chemo- and hormone- therapy used in the treatment of breast cancer increases the risk of thrombosis. Due to differences in health care services between developed and developing countries, the survival rate of women with breast cancer in developing countries is low. Consequently, ethnomedicines are used and their efficacy as potential alternatives are being scientifically explored. The seed oils of Kigelia africana, Ximenia caffra and Mimusops zeyheri have anti-proliferative effects on hormone-dependent (MCF-7) and cytotoxic effects on hormone-independent (MDA-MB-231) breast cancer cells. In this study, we determined if these seed oils reduce the thrombogenic ability of breast cancer cells by measuring the platelet surface expression of the activation-specific antigens CD62P and CD63. MDA-MB-231 and MCF-7 cells were pretreated with the seed oils before being exposed to whole blood of human female volunteers. An increase in CD62P and CD63 expression following whole blood exposure to untreated breast cancer cells was observed. Treated MDA-MB-231 cells reduced CD62P and CD63 expression while treated MCF-7 cells increased CD62P and decreased CD63 expression. Kigelia africana, Ximenia caffra and Mimusops zeyheri seed oils are able to reduce the thrombogenic ability of MDA-MB-231 breast cancer cells.

A novel solar absorber using activated carbon nanoparticles synthesized from bio-waste for the performance improvement of solar desalination unit

Enhancing the efficiency of low-cost solar-powered desalination technologies such as solar stills (SS) is essential to ensuring sustained access to potable water in water-stressed areas. In the present work, the potential enhancement of SS performance through the addition of different concentrations of activated carbon nanoparticles (ACNPs) to the standard black paint used to coat the absorber plate was explored. SSs were fabricated with absorber coated using black paint doped with 0, 5, 10 and 15 wt% ACNPs (denoted as CSS, MSS-5, MSS-10 and MSS-15, respectively) and the effect on water temperature and distillation efficiency determined. ACNPs were synthesized by crushing dead Kigelia Africana leaves and pyrolysis of the leaf powder in a muffle furnace at 500 °C. Absorber surface roughness analysis illustrated increasing roughness with increasing the loading of ACNPs in the nano-paint, leading to significant increase in heat transfer. Significant improvement in average water temperature (12.5%) and absorber (14.5%) was noted in the modified SS coated with 15 wt% ACNP over the CSS. The augmented temperature of this still enhanced the peak hourly and full-day water yield of MSS-15 by ⁓39.3%, compared to the conventional SS. The water quality analysis shows that the distilled water is appropriate for drinking. In conclusion, the synergetic effect of the high thermal conductivity and excellent solar absorption of the ACNP-based solar absorber improves the performance of the SS unit.

Facile Green Synthesis and Characterization of Titanium Dioxide Nanoparticles Using Kigelia africana (Lam) Benth., Aqueous Leaf Extract and its Antioxidant and Antibacterial Activity

Titanium nanoparticles are toxic to bacteria and have a widespread applications in different fields of research. Hence the present study aimed to synthesize the titanium dioxide nanoparticles by adopting green synthesis methodology using Kigelia africana leave extract as a biological reducing agent. The UV absorption spectra show characteristic absorption maxima corresponding to TiO2 nanoparticles at a wavelength of 512 nm confirms the formation of nanosized tin particles. The FT-IR spectrum of TiO2 nanoparticles show absorption bands at 3609 cm-1 and 3227 cm-1 corresponding to O-H stretching in alcoholic and carboxylic compounds, respectively. Absorption peaks at 1607, 2834, 1654 and 1324 cm-1 correspond to aromatic C=C vibrations, C-H stretching in aldehydes, C-H bending vibrations and aromatic C-N stretching vibrations, respectively. This confirms the involvement of bioactive compounds from the plant extract. The SEM and EDX studies confirmed that the nanoparticles are spherical to oval shape with an average particle size of 46 nm. The metal content in the nanoparticles was found to be 58.71%. The synthesized nanoparticles have potential growth inhibition activity against Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli). The DPPH radical scavenging activity of the nanoparticles synthesized was compared with that of aqueous leaf extract and standard ascorbic acid and proved that the nanoparticles have enhanced activity than aqueous leaf extract. The IC50 of the leaf extract, nanoparticles and the standard was found to be 31.55, 75.82 and 84.95 μg/mL, respectively. Kigelia africana leaf is shown in this work to be a valuable bioagent in the biosynthesis of TiO2 nanoparticles with increased biological activity.

Biocatalytic and biological activities of Kigelia africana mediated silver monometallic and copper-silver bimetallic nanoparticles

Aqueous extract of Kigelia africana leaves have been utilized for the synthesis of silver (AgNPs) and copper-silver bimetallic nanoparticles (Ag-CuNPs) that were generally found to be spherical and oval in shape. The synthesized nanoparticles were characterized using UV-Vis, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX), and transmission electron microscopy (TEM). The antimicrobial activities were evaluated against both gram-negative and gram-positive strains of bacteria. The UV-Vis and FTIR techniques revealed the formation of nanoparticles and the active components were adsorbed on the surface of the particles thereby stabilizing the nanoparticles. The SEM reveals uniform microspheres of AgNPs and anisotropic particles for Ag-CuNPs. TEM shows the size of synthesized particles. The nanoparticles inhibited the growth of both gram-negative and gram-positive bacteria. The bimetallic nanoparticles synthesized from aqueous extract of K. africana leaves showed greater inhibition against Escherichia coli as compared to the monometallic nanoparticles. The AgNPs was more effective for the reduction of 4-nitrophenol and 4-nitroaniline as compared to Ag-CuNPs. The results of this study confirmed that Kigelia africana leaf and fruit aqueous extract can successfully reduce metallic ions to synthesize metallic nanoparticles that have antimicrobial and biocatalytic properties.

In vitro antimicrobial, antibiofilm and antioxidant activities of six South African plants with efficacy against selected foodborne pathogens

Foodborne pathogens are a major cause of concern as they are responsible for food spoilage or microbial diseases, leading to economic loss to the food industry as well as health issues. The problem of increased resistance to available antimicrobial agents, and the ability of the microorganisms to form protective biofilms, strengthens their capacity to resist treatment. The antimicrobial, anti-biofilm and antioxidant activities and cytotoxicity of six South African plants, Carpobrotus edulis, Vachellia rehmanniana, Vachellia xanthophloea, Kigelia africana, Elephantorrhiza elephantina and Ochna pretoriensis, were investigated. Plants were selected based on traditional use against foodborne diseases or known antimicrobial activity. Serial microdilution and crystal violet assays were used to assess the antimicrobial and anti-biofilm potential of the extracts. Antioxidant activity of the extracts was determined against free radicals in vitro, and a tetrazolium-based cell viability assay was used to investigate cytotoxicity. Extracts were active against microorganisms implicated in causing foodborne diseases, with minimum inhibitory concentration (MIC) values ranging from 0.02 to 2.5 mg/ml. Acetone extracts of V. xanthophloea and C. edulis had noteworthy MIC values of 0.02 mg/ml against Enterobacter cloacae. Most extracts selectively reduced biofilm growth by at least 50% against the foodborne pathogens. The acetone extract of V. xanthophloea had the most significant anti-biofilm activity against Salmonella Typhimurium. The methanol extract of V. xanthophloea and the acetone extract of C. edulis had good antioxidant activity. Leaf extracts of the selected plants have useful bioactivities coupled with low cytotoxicity, providing impetus for further studies on possible development of these plants as protective food additives against microbial attack or oxidation.