The antimicrobial, antioxidative, anti-inflammatory activity and cytotoxicity of different fractions of four South African Bauhinia species used traditionally to treat diarrhoea

Wild Edible Flowers of Western Himalayas: Nutritional Characterization, UHPLC-QTOF-IMS-Based Phytochemical Profiling, Antioxidant Properties, and In Vitro Bioaccessibility of Polyphenols

Four edible flowers commonly consumed in the Western Himalayan region, namely, Bauhinia variegata (Kachnar), Tropaeolum majus (Nasturtium), Matricaria chamomilla (Chamomile), and Tagetes erecta (Marigold), were characterized for their nutritional and phytochemical composition. Through the UHPLC-QTOF-IMS-based metabolomics approach, 131 compounds were tentatively identified consisting of phenolic acids, flavonoid glycosides, terpenoids, amino acids, and fatty acid derivatives. Kaempferol and quercetin glycosides for Kachnar, apigenin glycosides and caffeoylquinic acid derivatives for Chamomile, patulin and quercetin derivatives for Marigold, cyanidin and delphinidin glycosides for Nasturtium were the predicted marker metabolites identified through non-targeted metabolomics. Kachnar and Chamomile scored best in terms of macronutrients and essential micronutrients, respectively. Nasturtium contained high concentrations of α-linolenic acid, anthocyanins, and lutein. Kachnar contained the highest total phenolic acids (63.36 ± 0.38 mg GAE g-1), while Marigold contained the highest total flavonoids (118.90 ± 1.30 mg QUE g-1). Marigolds possessed excellent free radical scavenging and metal chelation activities. Chamomile exhibited strong α-glucosidase inhibition activity, followed by Nasturtium. The in vitro gastrointestinal digestibility of flower extracts indicated that the bioaccessibility of phenolic acids was higher than that of flavonoids. Polyphenols from Nasturtium and Chamomile showed the highest bioaccessibility. The study is an attempt to characterize traditionally consumed edible flowers and promote their wider utilization in gastronomy and nutraceuticals.

Cucurbitacins B, E and I Concentrations and Relationship with Drought Tolerance in Bottle Gourd [Lagenaria siceraria (Molina) Standl.]

Bottle gourd [Lagenaria siceraria (Molina) Standl.]) is a relatively drought-tolerant cucurbit due to the high composition of unique biochemical compositions, including cucurbitacin. The objective of this study was to determine the concentrations of cucurbitacins in bottle gourd and their relationship to drought tolerance. The study assessed 12 bottle gourd accessions grown under two moisture levels (i.e., non-stressed (NS) and drought-stressed (DS)) and three drought stress intensities (i.e., mild, moderate, and severe) using a 12 × 2 × 3 factorial experiment designed in a randomized complete block design with three replications. Control studies were undertaken under glasshouse conditions. The content of cucurbitacins B, E, and I were quantified in leaves and roots using high-performance liquid Cchromatography-mass spectrometry (HPLC-MS). The free radical scavenging activities of pure cucurbitacins B, E, and I were quantified using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and a ferrulic acid power assay (FRAP). Results revealed that cucurbitacins B and I were present in accessions BG-48, BG-58, BG-70, BG-78, BG-79, BG-81, BG-52, and GC in leaves and roots under DS condition. The contents of cucurbitacins B and I were enhanced under increased drought intensity for accessions BG-48, BG-81, and GC. In all the leaf and root samples, cucurbitacin E was not detectable. Based on the DPPH test, pure cucurbitacins I, B, and E reduced free radicals at maximum values of 78, 60, and 66%, respectively. Based on the FRAP assay, pure cucurbitacins I, B, and E had maximum ferric-reducing powers of 67, 62, and 48%. Additionally, cucurbitacin I recorded the highest antioxidant activity compared to cucurbitacins B and E. Increased cucurbitacin accumulation and antioxidant properties indicate their role in minimising cell damage caused by oxidative stress under drought-stressed environments. The present study revealed that cucurbitacins B and I serve as novel biochemical markers for screening drought tolerance in bottle gourd or related cucurbits.

Phytochemical profiling of Salsola tetragona Delile by LC-HR/MS and investigation of the antioxidant, anti-inflammatory, cytotoxic, antibacterial and anti-SARS-CoV-2 activities

This study aimed to investigate the phytochemical composition and biological activity of Salsola tetragona Delile. (Amaranthaceae), a medicinal plant. The study evaluated the antioxidant potential of the crude extract and five fractions of S. tetragona using DPPH•, ABTS•+, CUPRAC, and metal chelating assays. The anti-inflammatory activity was determined using a protein denaturation assay, and the antibacterial activity was determined by the Minimum inhibitory concentrations (MICs) for the growth of Escherichia coli and Staphylococcus aureus strains. The MTT test and an in vitro scratch assay evaluated the effects on cell viability and cell migration. The potential anti-SARS-CoV-2 activity was assessed by analyzing the effects on the interaction between ACE2 and Spike protein. The bioactive compounds present in the plant were identified using LC-HR/MS analysis. The crude hydromethanolic extract (STM) and five fractions of S. tetragona, n-hexane (STH), dichloromethane (STD), ethyl acetate (STE), n-butanol (STB), and aqueous (STW) showed significant antioxidant activity in four different tests. In the anti-inflammatory assay, the ethyl acetate fraction exhibited significantly higher activity than Aspirin® (IC50 = 13 ± 5 µg/mL). The crude extract and its fractions showed positive antibacterial activity with similar MICs. In the cytotoxicity assay against the breast cancer cell line MCF7, the dichloromethane fractions (STD) were very effective and demonstrated superiority over the other fractions (IC50 = 98 µg/mL). Moreover, the potential of the extract and fractions as anti-SARS-CoV-2, the ethyl acetate, and dichloromethane fractions demonstrated important activity in this test. LC-HR/MS analysis identified 16 different phenolic compounds, Eleven of which had not been previously reported in the genus Salsola. The results suggest that the extracts of S. tetragona have the potential to become new sources for developing plant-based therapies for managing a range of diseases.

GC-ToF-MS Profiling and In Vitro Inhibitory Effects of Selected South African Plants against Important Mycotoxigenic Phytopathogens

The harmful effects following the ingestion of mycotoxin-contaminated food include the induction of cancers, mutagenicity, immune suppression, and toxicities that target organs of the digestive, cardiovascular, and central nervous systems. Synthetic fungicides are generally associated with a high toxic residue in food and the development of excessive fungal resistance. This study aimed to determine the antifungal activities against mycotoxigenic fungi of selected South African plant leaves and potentially develop plant-derived bio-fungicides, and, furthermore, to explore the in vitro antioxidant activity and the phytochemical spectra of the compounds of the selected medicinal plant extracts. The extracts were tested for antifungal activity against phytopathogenic strains using a microdilution broth assay. Bauhinia galpinii extracts exhibited the lowest minimum inhibitory concentration (MIC) against C. cladospoides and P. haloterans at 24 h incubation periods. C. caffrum had good antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) with 50% inhibitory concentration (IC50) values of 0.013 mg/mL while B. galpini had IC50 values of 0.053 against free radicals of 2,2'-azinobis (3-ethylbenzthiazoline-6-suphonic acid (ABTS). The antimycotoxigenic and antioxidant activity exerted by both B. galpinii and C. caffrum may well be attributed to high TPC. In the GC-ToF-MS analysis, all the selected medicinal plants exhibited the presence of Hexadecanoic acid at varying % areas, while both B. galpinii and C. caffum exhibited the presence of lupeol at % area 2.99 and 3.96, respectively. The compounds identified, particularly the ones with higher % area, may well explain the biological activity observed. Although the selected medicinal plants exhibited a notable biological activity, there is a need to explore the safety profiles of these plants, both in vitro and in vivo.

Medicinal Uses of the Fabaceae Family in Zimbabwe: A Review

The current study is aimed at providing a systematic review of the ethnomedicinal, phytochemical and pharmacological properties of Fabaceae species used as sources of traditional medicinies in Zimbabwe. Fabaceae is one of the well-known plant families of ethnopharmacological importance. Of the approximately 665 species of the Fabaceae family occurring in Zimbabwe, about 101 are used for medicinal purposes. Many communities in the country, mainly in peri-urban, rural and marginalized areas with limited access to healthcare facilities, rely on traditional medicines as their primary healthcare. The study reviewed research studies undertaken on Zimbabwe's Fabaceae species during 1959 to 2022. Information was gathered from literature sourced from Google Scholar, Science Direct, Scopus, PubMed, books, dissertations, theses and scientific reports. This study showed that 101 species are traditionally used to manage human and animal diseases in Zimbabwe. The genera with the highest number of medicinal uses are Indigofera, Senna, Albizia, Rhynchosia and Vachellia. Species of these genera are used as traditional medicines against 134 medical conditions, mainly gastrointestinal conditions, female reproductive conditions, respiratory conditions and sexually transmitted infections. Shrubs (39.0%), trees (37.0%) and herbs (18.0%) are the primary sources of traditional medicines, while roots (80.2%), leaves (36.6%), bark (27.7%) and fruits (8.9%) are the most widely used plant parts. Many of Zimbabwe's Fabaceae species used as sources of traditional medicines have been assessed for their phytochemical and pharmacological properties, corroborating their medicinal uses. However, there is a need to unravel the therapeutic potential of the family through further ethnopharmacological research focusing on toxicological studies, in vitro and in vivo models, biochemical assays and pharmacokinetic studies.

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.

Hydroalcoholic Extract of Myrcia bella Loaded into a Microemulsion System: A Study of Antifungal and Mutagenic Potential

Myrcia bella is a medicinal plant used for the treatment of diabetes, hemorrhages, and hypertension in Brazilian folk medicine. Considering that plant extracts are attractive sources of new drugs, the aim of the present study was to verify the influence of incorporating 70% hydroalcoholic of M. bella leaves in nanostructured lipid systems on the mutagenic and antifungal activities of the extract. In this work, we evaluated the antifungal potential of M. bella loaded on the microemulsion against Candida sp for minimum inhibitory concentration, using the microdilution technique. The system was composed of polyoxyethylene 20 cetyl ether and soybean phosphatidylcholine (10%), grape seed oil, cholesterol (10%: proportion 5/1), and purified water (80%). To investigate the mutagenic activity, the Ames test was used with the Salmonella Typhimurium tester strains. M. bella, either incorporated or free, showed an important antifungal effect against all tested strains. Moreover, the incorporation surprisingly inhibited the mutagenicity presented by the extract. The present study attests the antimicrobial properties of M. bella extract, contributing to the search for new natural products with biological activities and suggesting caution in its use for medicinal purposes. In addition, the results emphasize the importance of the use of nanotechnology associated with natural products as a strategy for the control of infections caused mainly by the genus Candida sp.

LC–DAD–MS Phenolic Characterisation of Six Invasive Plant Species in Croatia and Determination of Their Antimicrobial and Cytotoxic Activity

Invasive plants’ phytochemicals are important for their invasiveness, enabling them to spread in new environments. However, these chemicals could offer many pharmaceutical compounds or active ingredients for herbal preparations. This study provides the first LC–MS phytochemical screening of six invasive alien plant species (IAPS) in the Istria region (Croatia): Ailanthus altissima, Ambrosia artemisiifolia, Conyza canadensis, Dittrichia viscosa, Erigeron annuus, and Xanthium strumarium. The study aims to identify and quantify the phenolic content of their leaf extracts and assess their antimicrobial and cytotoxic potential. A total of 32 species-specific compounds were recorded. Neochlorogenic, chlorogenic, and 5-p-coumaroylquinic acids, quercetin-3-glucoside, and kaempferol hexoside were detected in all the tested IAPS. Hydroxycinnamic acid derivatives were the main components in all the tested IAPS, except in E. annuus, where flavanones dominated with a share of 70%. X. strumarium extract had the best activity against the tested bacteria, with an average MIC value of 0.11 mg/mL, while A. altissima and X. strumarium extracts had the best activity against the tested fungi, with an average MIC value of 0.21 mg/mL in both cases. All the plant extracts studied, except X. strumarium, were less cytotoxic than the positive control. The results provided additional information on the phytochemical properties of IAPS and their potential for use as antimicrobial agents.

Antibacterial, Mutagenic Properties and Chemical Characterisation of Sugar Bush (Protea caffra Meisn.): A South African Native Shrub Species

Protea caffra is used as a diarrhoeal remedy in South African herbal medicine, however, its pharmacological properties remain largely unknown. In the present study, extracts from different Protea caffra organs were screened against drug-sensitive and -resistant diarrhoeagenic pathogens using the microdilution assay (minimum inhibitory concentration, MIC). Twig extracts (70% methanol, MeOH) of the plant were purified and the resultant fractions screened for antibacterial properties (MIC). The chemical profiles of the fractions were determined by Gas Chromatography-Mass Spectrometry (GC-MS), while ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used to quantify the phenolic acids in the plant. The mutagenic properties of bioactive extracts were assessed using the Ames test. The extracts demonstrated weak-moderate antibacterial properties (MIC: 0.3–0.6 mg/mL). A cold ethyl acetate fraction of MeOH twig extract exhibited significant antibacterial properties (MIC = 0.078 mg/mL) against Enterococcus faecalis. The presence of antibacterial compounds (1-adamantane carboxylic acid, heptacosanol, levoglucosan, nonadecanol) in the plant was putatively confirmed based on GC-MS analysis. Furthermore, UHPLC-MS/MS analysis revealed varying concentrations of phenolic acids (0.08–374.55 µg/g DW). Based on the Ames test, the extracts were non-mutagenic thereby suggesting their safety. To a certain degree, the current study supports the traditional use of Protea caffra to manage diarrhoea among local communities in South Africa.

Pharmacopuncture of Bauhinia variegata Nanoemulsion Formulation against Diabetic Peripheral Neuropathic Pain

OBJECTIVES

The objective of the study was to prepare Bauhinia variegata loaded nanoemulsion(formulation and determine the efficacy of herbal drug formulation against diabetic peripheral neuropathic pain through acupuncture technique.

METHODS

Nine different ba tches of nanoemulsion (NE1 NE9) of BVN was prepared by varying the Smix ratio and the concentration of oil. BVN was characterized to determine particle size, shape, zeta potential, polydispersity index, optical transmittance, drug release profile and stora ge stability.The optimized formulation was subjected to plantar test, behavioral tests of neuropathic pain and Von Frey filament stimulation test. Diabetes was induced by intraperitoneal injection of freshly prepared solution of Streptozotocin (60 mg/kg) to the experimental rats. Animals were made diabetic divided into four groups, Group I was untreated normal control group, Group II was diabetic control group, Group III was Bauhinia variegata extract ( treated group (100 mg/kg/day, p.o) and Group IV was BVN treated groups (100 mg/kg/day, p.o) acute and chronically.

RESULTS

The prepared B. variegata loaded nanoemulsion was nanosized (124 nm), spherical, uniform and stable over the period of 180 days with no change in physiochemical properties. The bl ood glucose and body weight of animals was normalizing after four weeks of treatment that was significant with BVN in comparison to diabetic control group. The chronic administration of BVN significantly (P<0.001) decreased hind paw withdrawal latency an d attenuated mechanical allodynia as compared with diabetic rats.

CONCLUSION

Thus, BVN may be an effective drug formulation against diabetic peripheral neuropathic pain.

Antioxidant Rich Extracts of Terminalia ferdinandiana Inhibit the Growth of Foodborne Bacteria

Terminalia ferdinandiana (Kakadu plum) is a native Australian plant containing phytochemicals with antioxidant capacity. In the search for alternatives to synthetic preservatives, antioxidants from plants and herbs are increasingly being investigated for the preservation of food. In this study, extracts were prepared from Terminalia ferdinandiana fruit, leaves, seedcoats, and bark using different solvents. Hydrolysable and condensed tannin contents in the extracts were determined, as well as antioxidant capacity, by measuring the total phenolic content (TPC) and free radical scavenging activity using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay. Total phenolic content was higher in the fruits and barks with methanol extracts, containing the highest TPC, hydrolysable tannins, and DPPH-free radical scavenging capacity (12.2 ± 2.8 g/100 g dry weight (DW), 55 ± 2 mg/100 g DW, and 93% respectively). Saponins and condensed tannins were highest in bark extracts (7.0 ± 0.2 and 6.5 ± 0.7 g/100 g DW). The antimicrobial activity of extracts from fruit and leaves showed larger zones of inhibition, compared to seedcoats and barks, against the foodborne bacteria Listeria monocytogenes, Bacillus cereus, Methicillin resistant Staphylococcus aureus, and clinical isolates of Pseudomonas aeruginosa. The minimum inhibitory concentration and minimum bactericidal concentration in response to the different extracts ranged from 1.0 to 3.0 mg/mL. Scanning electron microscopy images of the treated bacteria showed morphological changes, leading to cell death. These results suggest that antioxidant rich extracts of Terminalia ferdinandiana fruits and leaves have potential applications as natural antimicrobials in food preservation.

Antibacterial and antibiofilm activity of acetone leaf extracts of nine under-investigated south African Eugenia and Syzygium (Myrtaceae) species and their selectivity indices

BACKGROUND

Antimicrobial resistance (AMR) remains an important global health issue but the gap between AMR and development of new antimicrobials is increasing. Plant extracts may have good activity per se or may be sources of effective antimicrobial compounds which can act against planktonic and/or biofilms of pathogens. We determined the antimicrobial efficacy and cytotoxicity of some under-investigated plants from the Myrtaceae family endemic to South Africa. The ability of the plant extracts to inhibit or destroy pre-formed bacterial biofilms was also determined.

METHODS

Based on previous preliminary in vitro screening and on chemotaxonomy, nine species from the Myrtaceae family were selected. The antimicrobial activity of the crude acetone leaf extracts was determined against six common nosocomial pathogens, namely: Gram-positive bacteria (Bacillus cereus, Enterococcus faecalis, Staphylococcus aureus), Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella Typhimurium) using a two-fold serial microdilution assay with p-iodonitrotetrazolium violet as growth indicator. The number of antimicrobial compounds present in extracts was determined by bioautography. Cytotoxicity of extracts was determined against Vero kidney cells using a colorimetric tetrazolium-based assay. The total antibacterial activity (TAA) in ml/g and selectivity index (LC50/MIC) of the plant extracts were calculated. A modified crystal violet assay was used to determine the antibiofilm activity of the extracts.

RESULTS

Syzygium legatii, Syzygium masukuense, and Syzygium species A had the best activities against Gram-negative and Gram-positive bacteria (MIC) values ranging from 0.04-0.08 mg/ml. Eugenia erythrophylla had the best MIC (0.02 mg/ml) against Bacillus cereus. Many extracts had relatively low cytotoxicity (LC50 > 20 μg/ml) leading to reasonable selectivity indices. Three leaf extracts (Syzygium masukuense, Syzygium species A, and Eugenia natalitia) were moderately cytotoxic (20 μg/ml < LC50 < 100 μg/ml). The plant extracts had a good capacity to reduce biofilm formation and good to poor potential to destroy pre-formed biofilms.

CONCLUSIONS

The plant species examined in this study had varying degrees of antibacterial activity against bacterial planktonic and biofilm forms with some having good activity against both forms. Several of these selected species may be potential candidates for further investigation to isolate antimicrobial compounds and to determine the mechanism of activity.

Antibacterial activity and mode of action of acetone crude leaf extracts of under-investigated Syzygium and Eugenia (Myrtaceae) species on multidrug resistant porcine diarrhoeagenic Escherichia coli

BACKGROUND

Diarrhoea, a global economically important disease burden affecting swine and, especially piglets, is commonly caused by infection with entero-toxigenic E. coli (ETEC). Adherence of ETEC to porcine intestinal epithelial cells following infection, is necessary for its pathogenesis. While antimicrobials are commonly given as therapy or as feed additives for prophylaxis against microbial infections, the concern over increased levels of antimicrobial resistance necessitate the search for safe and effective alternatives in livestock feed. Attention is shifting to natural products including plants as suitable alternatives to antimicrobials. The activity of acetone crude leaf extracts of nine under-explored South African endemic plants from the Myrtaceae family with good antimicrobial activity were tested against pathogenic E. coli of porcine origin using a microplate serial dilution method. Bioautography, also with p-iodonitrotetrazolium violet as growth indicator was used to view the number of bioactive compounds in each extract. In vitro toxicity of extracts was determined against Caco-2 cells using the 3-(4,5-dimethythiazolyl-2)-2,5-diphenyltetrazolium bromide reduction assay. The antimicrobial susceptibility of E. coli isolates was tested on a panel of antimicrobials using the Kirby-Bauer agar diffusion method while the anti-adherence mechanism was evaluated using a Caco-2 cell enterocyte anti-adhesion model.

RESULTS

The MIC of the extracts ranged from 0.07-0.14 mg/mL with S. legatii having the best mean MIC (0.05 mg/mL). Bioautography revealed at least two active bands in each plant extract. The 50% lethal concentration (LC₅₀) values ranged between 0.03-0.66 mg/mL. Eugenia zeyheri least cytotoxic (LC₅₀ = 0.66 mg/ml) while E. natalitia had the highest cytotoxicity (LC₅₀ = 0.03 mg/mL). All the bacteria were completely resistant to doxycycline and colistin sulphate and many of the plant extracts significantly reduced adhesion of E. coli to Caco-2 cells.

CONCLUSIONS

The extracts of the plants had good antibacterial activity as well as a protective role on intestinal epithelial cells against enterotoxigenic E. coli bacterial adhesion. This supports the potential use of these species in limiting infection causes by E. coli. Some of these plants or extracts may be useful as phytogenic feed additives but it has to be investigated by animal feed trials.

Modulation of the resistance to norfloxacin in Staphylococcus aureus by Bauhinia forficata link

Microdilution assays were performed in order to evaluate the antimicrobial activity of the ethanoic extract from the leaves of Bauhinia forficate (EEBF) against different microorganisms. The extract did not present inner antimicrobial activities against the tested strains. However, EEBF was able to modulate the norfloxacin-resistance against Staphylococcus aureus SA1199-B that overproduce the NorA efflux pump, once sub-inhibitory concentrations of EEBF reduced the minimal inhibitory concentratio of the norfloxacin in 87.5%. This modulatory effect was also found when the antibiotic was replaced by ethidium bromide, suggesting that EEBF acts probably by inhibition of NorA, allowing the antibiotic accumulation intracellularly, and making the line more sensitive. These results point out the EEBF potential as a source of NorA inhibitors that could be used in combination with norfloxacin for treatment of infections caused by multidrug-resistant S. aureus.

A review of the traditional use of southern African medicinal plants for the treatment of selected parasite infections affecting humans

ETHNOPHARMACOLOGICAL RELEVANCE

Worldwide, more than three billion cases of parasitic disease are reported yearly and it is likely that this figure is substantially under-estimated. Approximately one in six people globally are estimated to be infected with at least one parasite species annually. In South Africa, the prevalence of Schistosoma haematobium (bilharzia) and intestinal worms and helminths are particularly high, especially in children and in crowded or poorer rural communities with inadequate sanitation and nutrition. Despite alarmingly high estimates, medical research into parasitic diseases remains neglected and only malaria receives significant attention and funding. Traditional medicines have been used for centuries in Africa by multiple ethnic groups and many people rely on these healing systems as their primary healthcare modality. The traditional use of South African medicinal plants to treat parasite infestations is relatively well documented, and it is important to link these traditional uses to scientific evidence validating efficacy.

AIM OF THE STUDY

To document the medicinal plants used for parasitic infections and critically review the literature on the anti-parasitic properties of South African plants against some neglected parasitic diseases.

MATERIALS AND METHODS

A review of the literature (ethnobotanical books and publications documenting traditional plant use) was undertaken related to specific medicinal use for parasitic infections in Southern Africa. Inclusion criteria focused on human use. Exclusion criteria included veterinary use and malaria due to the extensive nature of these subject matters. An in-depth analysis of previous studies was undertaken and future prospectives are considered.

RESULTS

In particular, bilharzia, gastrointestinal worms and helminths, ectoparasites, trichomoniasis, leishmaniasis and trypanosomiasis are reviewed with special emphasis on the gaps in research.

CONCLUSIONS

Despite the availability of relatively extensive ethnobotanical records on the anti-parasitic properties of southern African medicinal plants, the antiparasitic properties of many plants have been poorly examined. There was in many instances a lack of evidence to support traditional use of many species towards some parasites and research is urgently needed in this area.

Pharmacological credence of the folklore use of Bauhinia malabarica in the management of jaundice

The information on the hepatoprotective effect of Bauhinia malabarica Roxb. (Family Leguminosae) used in the folkloric medical practice in Malabar coast and Walayar valley of southern India for the treatment of liver related disorders is completely unknown. Hence, the efficacy of the aqueous methanolic extract of stem bark of B. malabarica (AqMeOH-Ba) was evaluated for liver function serum biochemical markers along with the antioxidant markers in liver tissues of Wistar albino rats. The biochemical observations as well as the histopathological examination of liver sections manifested considerable hepatoprotective activity of B. malabarica stem bark, and thus validated the folkloric claim.

Simultaneous optimization of ultrasonic-assisted extraction of antioxidant and anticoagulation activities of compounds from Leonurus japonicus Houtt. by response surface methodology

Leonurus japonicus Houtt. is a herbaceous annual of the Lamiaceae family with pantropical distribution; it is called motherwort in China. It plays important roles in anticoagulation and antioxidation. This study aimed to explore the optimization of ultrasound-assisted extraction of multiple compounds from motherwort as well as their antioxidant and anticoagulation activities using response surface methodology. Box–Behnken design was employed to optimize three significant influences, namely extraction time, extraction temperature and ethanol concentration. The optimum extraction parameters acquired based on a combination of the yield of the target compounds and their antioxidant and anticoagulation activities were an extraction time of 38.2 min, an extraction temperature of 30.0 °C, an ethanol concentration of 48.9% (v/v), a solid–liquid ratio of 30.0 mL g⁻¹ and an ultrasonic power of 500.0 W. Under the optimal conditions, the maximal yield of the anticoagulation and antioxidant compounds of motherwort was 0.994%; the thrombin time was 19.872 s; prothrombin time was 8.270 s; the activated partial thromboplastin time was 15.535 s; the fibrinogen was 1.420 g L⁻¹; and the 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activity was 1.503 mg mL⁻¹. The optimized conditions model showed a good correlation between the predicted and experimental values. According to the results of our study, the optimization extraction significantly enabled study of the anticoagulation and antioxidant activities of compounds in motherwort; this may contribute to future research on the pharmacological activities of motherwort.

Leonurus japonicus Houtt. is a herbaceous annual of the Lamiaceae family with pantropical distribution; it is called motherwort in China.

Extract of Bauhinia vahlii Shows Antihyperglycemic Activity, Reverses Oxidative Stress, and Protects against Liver Damage in Streptozotocin-induced Diabetic Rats

Background:

Several studies have affirmed the effectiveness of some Bauhinia plants as antihyperglycemic agents.

Objective:

We investigated the possible effect of Bauhinia vahlii leaves extract in reducing hyperglycemia and reversing signs of organ damage associated with diabetes in streptozotocin (STZ) rat model.

Materials and Methods:

Both polar fraction of the B. vahlii leaves (defatted ethanolic extract [DEE]) and nonpolar fraction (n-hexane extract) were evaluated in vitro for α-glucosidase inhibition and 2,2-diphenyl-1-picrylhydrazyl radical scavenging potential. DEE was selected for further in vivo studies and was administered at two doses, i.e., 150 or 300 mg/kg to STZ-diabetic rats for 4 weeks.

Results:

Only DEE exhibited in vitro antioxidant and antihyperglycemic activities and its oral administration at both dose levels resulted in significant reduction in fasting blood glucose and glycated hemoglobin. Furthermore, signs of oxidative stress as indicated by hepatic reduced glutathione, nitric oxide, and malondialdehyde levels were completely reversed. In addition, histopathological examination and measurement of serum aspartate transaminase and alanine transaminase levels showed that DEE protected the liver from signs of liver pathogenesis when compared to diabetic untreated animals and those treated with metformin. Phytochemical analysis of DEE showed high flavonoids content with quercitrin as the major constituent along with other quercetin glycosides.

Conclusion:

This study strongly highlights the possible beneficial effect of B. vahlii leaves extract in relieving hyperglycemia and liver damage in STZ-diabetic rats and recommends further investigation of the value of quercetin derivatives in controlling diabetes and ameliorating liver damage associated with it.

SUMMARY

The polar fraction of the Bauhinia vahlii leaves (defatted ethanolic extract [DEE]) exhibited both in vitro antioxidant activity in 2,2-diphenyl-1-picrylhydrazyl scavenging assay and strong α-glucosidase inhibition while the nonpolar fraction (n-hexane extract) failed to show any activity in both assays. DEE was further investigated in streptozotocin-induced diabetic rat model where oral administration of DEE at 2 doses (150 and 300 mg/kg) for 4 weeks resulted in significant reduction in fasting blood glucose and glycated hemoglobin and reversal of oxidative stress signs as indicated by measurement of hepatic reduced glutathione, nitric oxide, and malondialdehyde levels. In addition, histopathological examination and measurement of serum aspartate transaminase and alanine transaminase levels showed that DEE protected the liver from signs of pathogenesis observed in diabetic untreated rats. Phytochemical analysis of DEE showed high flavonoid content with quercitrin as the major constituent (62.9 ± 0.18 mg/mg).

Abbreviations used: ALT: Alanine transaminase, AST: Aspartate transaminase, DEE: Defatted ethanol extract, DPPH: 2,2-diphenyl-1-picrylhydrazyl, FBG: Fasting blood glucose, GAE: Gallic acid equivalent, GSH: Reduced glutathione, Hb1Ac: Glycated hemoglobin, HE: Hexane extract MDA: Malondialdehyde, QE: Quercetin equivalent, STZ: Streptozotocin, TAC: Total antioxidant capacity.

Antimicrobial natural product research: A review from a South African perspective for the years 2009-2016

ETHNOPHARMACOLOGICAL RELEVANCE

This review provides information on the antimicrobial research which has taken place on South African natural products for the last eight years (2009-2016). This important field is the backbone of all studies involving the use of medicinal plants against infectious diseases and hence can form the mainstay for future studies.

MATERIALS AND METHODS

All publications within the years 2009-2016 were considered. Exclusion criteria were studies not involving South African medicinal natural products and those publications where full articles could not be accessed. An overview of the most common experimental methods used and new advances in terms of antimicrobial investigations are provided. Disease categories selected for further investigation were skin and wounds, respiratory, gastrointestinal, sexually transmitted and ophthalmic infections amongst others. Alternate natural products and combinations studies were also included.

RESULTS

The minimum inhibitory concentration (MIC) was the most commonly used experimental method to determine antimicrobial activity. Staphylococcus aureus was the most commonly tested skin pathogen and Klebsiella pneumoniae was the most common pathogen implicated in respiratory disorders. Only 20% of gastrointestinal studies included commonly implicated pathogens such as Shigella flexneri and Campylobacter species.

CONCLUSION

Multidisciplinary studies have emerged as a strong support for antimicrobial investigations and show the importance of including toxicity when studying antimicrobial efficacy. Alternate approaches (for example biofilms and quorum sensing) at examining antimicrobial effects are encouraged. Studies on resistant strains require more insight and future recommendations should look at consistent dosing and investigations on compound interactions amongst others.

Optimisation of Pueraria isoflavonoids by response surface methodology using ultrasonic-assisted extraction

Puerariae Lobatae Radix (PLR) exerts cyto-protective effect against oxidative stress due to its high isoflavonoid content. In this study, the ultrasonic-assisted extraction condition for the maximum recovery of isoflavonoids with high cyto-protective effect was optimised by response surface methodology (RSM). A second-order polynomial fitted the experimental data (R²: 0.9736; p-value <0.0001). The optimal extraction parameters were determined as: extraction time 16.02min, ethanol concentration 41.41% and liquid-to-solid ratio 44.35mL/g. Practical experiments with extraction time 16.00min, ethanol concentration 41.00% and liquid-to-solid ratio 44.00mL/g were carried out in triplicate. This subsequently yielded a cell viability of 82.90±0.78% against hydrogen peroxide-induced oxidative stress on EA.hy926, and was comparable to the predicted of 85.60%. Five chemical constituents in the extract were identified to exert cyto-protective effect. Taken together, this method successfully integrated RSM and the partial least squares regression method to optimise the PLR extract with highest cyto-protective activity.

Melissa officinalis Protects against Doxorubicin-Induced Cardiotoxicity in Rats and Potentiates Its Anticancer Activity on MCF-7 Cells

Cardiotoxicity is a limiting factor of doxorubicin (DOX)-based anticancer therapy. Due to its beneficial effects, we investigated whether standardized extract of Melissa officinalis (MO) can attenuate doxorubicin-induced cardiotoxicity and can potentiate the efficacy of DOX against human breast cancer cells. MO was administered orally to male albino rats once daily for 10 consecutive days at doses of 250, 500 and 750 mg/kg b.wt. DOX (15 mg/kg b.wt. i.p.) was administered on the 8^th day. MO protected against DOX-induced leakage of cardiac enzymes and histopathological changes. MO ameliorated DOX-induced oxidative stress as evidenced by decreasing lipid peroxidation, protein oxidation and total oxidant capacity depletion and by increasing antioxidant capacity. Additionally, MO pretreatment inhibited inflammatory responses to DOX by decreasing the expressions of nuclear factor kappa-B, tumor necrosis factor-alpha and cyclooxygenase-2 and the activity of myeloperoxidase. MO ameliorated DOX-induced apoptotic tissue damage in heart of rats. In vitro study showed that MO augmented the anticancer efficacy of DOX in human breast cancer cells (MCF-7) and potentiated oxidative damage and apoptosis. Thus, combination of DOX and MO may prove future cancer treatment protocols safer and more efficient.

Reversal of fluconazole resistance induced by a synergistic effect with Acca sellowiana in Candida glabrata strains

CONTEXT

The increased incidence of non-albicans Candida (NAC) resistant to fluconazole (FLZ) makes it necessary to use new therapeutic alternatives. Acca sellowiana (O.berg) Burret (Myrtaceae) is a guava with several proven biological activities. The interaction with fluconazole can be a feasible alternative to overcome this resistance.

OBJECTIVE

This study evaluates the in vitro antifungal activity of fractions obtained from the lyophilized aqueous extract of the leaves of A. sellowiana against resistant strains of NAC.

MATERIALS AND METHODS

The antifungal activity of the fractions was evaluated at 500 μg/mL by microdilution method. Checkerboard assay was performed to determine the effect of the combination of the F2 fraction and antifungal at concentrations: MIC/4, MIC/2, MIC, MIC × 2 and MIC × 4.

RESULTS

Candida glabrata showed the lowest MIC values (500-3.90 μg/mL) and the F2 active fraction was the most effective. The association of F2 with FLZ showed a strong synergistic effect (FICI ≤ 0.5) against 100% of C. glabrata resistant isolates. Moreover, the F2 active fraction has demonstrated that probably acts in the cell wall of these yeasts. There was no observed acute dermal toxicity of lyophilized aqueous extract of leaves of A. sellowiana on pig ear skin cells.

DISCUSSION AND CONCLUSION

The interaction between substances present in the F2 active fraction is possibly responsible for the antifungal activity presented by this fraction. This study is unprecedented and suggests that the combination of F2 active fraction and FLZ might be used as an alternative treatment for mucocutaneus infections caused by C. glabrata resistant.

Phytochemical, antioxidant and antidiabetic evaluation of eight Bauhinia L. species from Egypt using UHPLC-PDA-qTOF-MS and chemometrics

Bauhinia L. (Fabaceae) comprises ca. 300-350 plant species, many of which are traditionally used in folk medicine for their antidiabetic, antioxidant and anti-inflammatory effects. Bauhinia s.l. recently has been subdivided into 9 genera based on phylogenetic data: Bauhinia s.str., Barklya, Brenierea, Gigasiphon, Lysiphyllum, Phanera, Piliostigma, Schnella (American Phanera) and Tylosema. The aerial parts of 8 species corresponding to 5 genera were analyzed: Bauhinia forficata, Bauhinia variegata, B. variegata var. candida, Bauhinia galpinii, Schnella glabra, Piliostigma racemosa, Phanera vahlii and Lysiphyllum hookeri. Leaves and shoots were subjected to metabolite profiling via UHPLC-PDA-qTOF-MS coupled to multivariate data analyzes to identify compound compositional differences. A total of 90 metabolites were identified including polyphenols and fatty acids; flavonoid conjugates accounted for most of the metabolite variation observed. This study provides a comprehensive map of polyphenol composition in Bauhinia and phytochemical species aggregations are consistent with recent Bauhinia genus taxonomic relationship derived from phylogenetic studies. DPPH radical scavenging and α-glucosidase inhibitory assays were also performed to assess selected aspects of the antioxidant and antidiabetic potential for the examined species with respect to metabolite profiles.

Antimicrobial resistance (AMR) and plant-derived antimicrobials (PDAms) as an alternative drug line to control infections

Infectious diseases caused by antimicrobial-resistant microbes (ARMs) and the treatment are the serious problems in the field of medical science today world over. The development of alternative drug line to treat such infectious diseases is urgently required. Researches on ARMs revealed the presence of membrane proteins responsible for effusing the antibiotics from the bacterial cells. Such proteins have successfully been treated by plant-derived antimicrobials (PDAms) synergistically along with the commercially available antibiotics. Such synergistic action usually inhibits the efflux pump. The enhanced activity of plant-derived antimicrobials is being researched and is considered as the future treatment strategy to cure the incurable infections. The present paper reviews the advancement made in the researches on antimicrobial resistance along with the discovery and the development of more active PDAms.

Lupeol: An antioxidant triterpene in Ficus pseudopalma Blanco (Moraceae)

OBJECTIVE

To assess the antioxidant activity of Ficus pseudopalma Blanco (Moraceae) (F. pseudopalma) and characterize the active components present in it.

METHODS

Column chromatography of crude ethanol leaf extract of F. pseudopalma was performed and seven fractions were obtained, labeled as F1, F2, F3, F4, F5, F6, F7. DPPH, FRAP, Griess, Fenton and superoxide radical scavenging assays were performed to assess the antioxidant ability of the fractions. Thin layer chromatography (TLC), high performance liquid chromatography and Fourier transfer infrared spectroscopy (FTIR) were performed to identify and characterize the bioactive component present in each fractions of F. pseudopalma.

RESULTS

DPPH and FRAP assay showed that F5, F6 and F7 exhibited the good proton accepting ability and reducing power as compared to the other fractions. All fractions exhibited a good nitric oxide radical scavenging activity wherein F1, F2 and F3 showed the highest inhibition. However, all of the fractions exhibited a stimulatory activity on hydroxyl and superoxide radicals. Lupeol matched one of the spots on the thin layer chromatography chromatogram of the fractions. Linear gradient high performance liquid chromatography and spiking of lupeol with the fraction revealed the presence of 5.84 mg/L lupeol in F6. Infrared spectra of the fractions revealed the presence of C-C, OH, aromatic C=C and C=O groups.

CONCLUSIONS

The identified lupeol in F. pseudopalma may be responsible for the exhibited antioxidant property of the plant. Furthermore, knowing the antioxidant capability of the plant, F. pseudopalma can be developed into products which can help prevent the occurrence of oxidative stress related diseases.

Are plants used for skin care in South Africa fully explored?

ETHNOPHARMACOLOGICAL RELEVANCE

South Africa is an important focal point of botanical diversity, and although many plant species have been used since ancient times in ethnomedicine, only a few species have hitherto been fully investigated scientifically. A large proportion of the South African population use traditional medicines for their physical and psychological health needs. Many medicinal plants have recently gained popularity as ingredient in cosmetic formulations based on their ethnomedicinal values and many cosmetic products sold in stores are of natural origin. The present review discusses the ethnopharmacological values, pharmacological and toxicological evidence of 117 plant species grown in South Africa, which are used traditionally for skin care purposes. Special focus was on their traditional use for many skin disorders in order to identify their therapeutic potential, the state of ethnopharmacological knowledge and special emphasis has been on areas which require further research.

MATERIALS AND METHODS

The information regarding all 117 plant species mentioned was extracted from Sci-Finder, Science direct, Medline and Google Scholar. All the available relevant data for medicinal plants was collated from literature review articles from the 19th century to early 2013.

RESULTS

The extracts from different parts of plants exhibited significant pharmacological properties, proving significant skin care potentials. Special emphasis was on those plant species which still need further exploration and these have been documented separately.

CONCLUSIONS

Despite the immense use of plants in ethnomedicine for skin care, limited research has been done on the activity of the crude extracts and very little on the active constituents. Consequently, almost 35 out of the 117 species are totally unexplored in the area of skin care. This investigation would be of interest to a broad readership including those researchers working in this field. The plant species namely: Greyia flanaganii, Sideroxylon inerme, Sclerocarya birrea, Calodendrum capense, Hyaenanche globosa, Harpephyllum caffrum, Ximenia americana, Leucosidea sericea Artemisia afra, and six Aloe species have been scientifically validated by our research group for skin hyperpigmentation problems.

Shedding some light over the floral metabolism by arum lily (Zantedeschia aethiopica) spathe de novo transcriptome assembly

Zantedeschia aethiopica is an evergreen perennial plant cultivated worldwide and commonly used for ornamental and medicinal purposes including the treatment of bacterial infections. However, the current understanding of molecular and physiological mechanisms in this plant is limited, in comparison to other non-model plants. In order to improve understanding of the biology of this botanical species, RNA-Seq technology was used for transcriptome assembly and characterization. Following Z. aethiopica spathe tissue RNA extraction, high-throughput RNA sequencing was performed with the aim of obtaining both abundant and rare transcript data. Functional profiling based on KEGG Orthology (KO) analysis highlighted contigs that were involved predominantly in genetic information (37%) and metabolism (34%) processes. Predicted proteins involved in the plant circadian system, hormone signal transduction, secondary metabolism and basal immunity are described here. In silico screening of the transcriptome data set for antimicrobial peptide (AMP) –encoding sequences was also carried out and three lipid transfer proteins (LTP) were identified as potential AMPs involved in plant defense. Spathe predicted protein maps were drawn, and suggested that major plant efforts are expended in guaranteeing the maintenance of cell homeostasis, characterized by high investment in carbohydrate, amino acid and energy metabolism as well as in genetic information.