Phenolic composition, antioxidant and acetylcholinesterase inhibitory activities of Sclerocarya birrea and Harpephyllum caffrum (Anacardiaceae) extracts

Modulation of MAPK/NF-κB Pathway and NLRP3 Inflammasome by Secondary Metabolites from Red Algae: A Mechanistic Study

The pharmacological properties of seaweeds are diverse. No studies have been conducted on the protective effect of Galaxaura oblongata (GOE) against lippopolysaccharide (LPS)-induced inflammation in the brain. This study is divided into three phases, the first of which is the initial phase. In vitro study includes antioxidant, radical scavenging, and anti-inflammatory activities, including cyclooxygenase-1 (COX1), COX2, NO, acetylcholine inhibition, sphingosine kinase 1, tumor necrosis factor α (TNF-α), and interleukin-6, as well as antioxidant and radical-scavenging activities, including 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azinobis(3-ethylbenzothiazoline)-6-sulfonic acid. Using LPS-induced acute inflammation, the second phase was conducted in vivo. Antioxidant and anti-inflammatory assays were performed to investigate the protective role of GOE. In addition to the phytochemical analysis, the bioactive content of GOE was also investigated. In vitro results demonstrated the potential of GOE as an antioxidant, anti-inflammatory, and neuroprotective agent. A study using LPS as an induced lung injury and neuroinflammation model confirmed the in vitro results. The GOE significantly reduced inflammatory, oxidative, and neurodegenerative biomarkers based on histopathological and immuno-histochemistry results. Based on computational drug design, four target proteins were approved: nuclear factor κB, mitogen-activated protein kinases, TNF-α, and NLRP3. Using polyphenolic compounds in GOE as ligands demonstrated good alignment and affinity against the three proteins. Finally, the current study offers a new approach to developing drug leads considering GOE's protective and curative roles.

Neuroprotective and nephroprotective effects of Ircinia sponge in polycyclic aromatic hydrocarbons (PAHs) induced toxicity in animal model: a pharmacological and computational approach

The present study investigated the neuroprotective and nephroprotective effects of the sponge Ircinia sp. ethyl acetate extract (ISPE) against persistent aromatic pollutants in vitro and in vivo. Different exponential experimental assays were applied to this study. An in vitro study to investigate the potential therapeutic effect of ISPE using antioxidants (for example, ABTS and DPPH) and anti-Alzheimer assays (inhibition of acetylcholinesterase); the in-vivo study was designed to evaluate the protective effect of ISPE as neuroprotective and nephroprotective against the destructive effect of PAH. Several assays included oxidative assays (LPO), antioxidant biomarkers (GSH, GST), and inflammatory and neurodegenerative biomarkers (PTK,SAA). Additionally, the results were confirmed using histopathological examination. The in silico screening study improved the in vitro and in vivo findings through interaction between the aryl hydrocarbon receptor (AHR) and the polyphenolic content of ISPE extract, which was determined using LCMSM. The results and discussion showed that ISPE exhibited a promising antioxidant and anti-acetylcholinesterase activity as evidenced by IC₅₀ values of 49.74, 28.25, and 0.18 µg/mL in DPPH, ABTS, and acetylcholinesterase inhibition assays, respectively. In vivo, the study showed that animals receiving ISPE before poly aromatic hydrocarbons administration PAHs (Prot, ISPE) showed significant amelioration in kidney functions manifested by the reduction of serum urea, uric acid, and creatinine by 40.6%, 66.4%, and 134.8%, respectively, concerning PAH-injected mice (HAA). Prot, ISPE revealed a decline in malondialdehyde (MDA) and total proteins (TP) in kidney and brain tissues by 73.63% and 50.21%, respectively, for MDA and 59.82% and 80.41%, respectively, for TP with respect to HAA. Prot, ISPE showed significant elevation in reduced glutathione (GSH) and glutathione transferase (GST) in kidney and brain tissues and reduction in the inflammatory and pre-cancerous biomarkers, namely, serum protein tyrosine kinases (PTKs) and serum amyloid A (SAA). These findings were further supported by histopathological examination of kidney and brain tissues, which revealed normal structure approaching normal control. Metabolic profiling of ISPE using LC-MS-MS showed the presence of fourteen polyphenolic compounds belonging mainly to phenolic acids and flavonoids. In silico study revealed that all the tested compounds exerted certain binding with the aryl hydrocarbon receptor, where rutin showed the best fitting (ΔG =  - 7.6 kcal/mol^-1) with considerable pharmacokinetic and pharmacodynamic properties revealed from in silico ADME (Absorption, Distribution, Metabolism, and Excretion) study. Hence, it can be concluded that the Ircinia sponge showed a promising protective effect versus kidney and brain toxicity triggered by PAHs.

Novel Anti-Acetylcholinesterase Effect of Euonymus laxiflorus Champ. Extracts via Experimental and In Silico Studies

Alzheimer's disease (AD) is the most common form of dementia, which is recorded as a global health issue. Natural acetylcholinesterase inhibitors (AChEIs) are considered a helpful therapy for the management of symptoms of patients with mild-to-moderate AD. This work aimed to investigate and characterize Euonymus laxiflorus Champ. (ELC) as a natural source of AChEIs compounds via in vitro and virtual studies. The screening parts used, including the leaves, heartwood, and trunk bark of ELC, revealed that the trunk bark extract possessed the highest activity, phenolics and flavonoid content. The in vitro anti-Alzheimer activity of ELC trunk bark was notably reclaimed for the first time with comparable effect (IC₅₀ = 0.332 mg/mL) as that of a commercial AChEI, berberine chloride (IC₅₀ = 0.314 mg/mL). Among various solvents, methanol was the most suitable to extract ELC trunk bark with the highest activity. Twenty-one secondary metabolites (1-21) were identified from ELC trunk bark extract, based on GCMS and UHPLC analyses. Of these, 10 volatile compounds were identified from this herbal extract for the first time. One phenolic (11) and seven flavonoid compounds (15-21) were also newly found in this herbal extract. Of the identified compounds, chlorogenic acid (11), epigallocatechin gallate (12), epicatechin (13), apigetrin (18), and quercetin (20) were major compounds with a significant content of 395.8-2481.5 μg/g of dried extract. According to docking-based simulation, compounds (11-19, and 21) demonstrated more effective inhibitory activity than berberine chloride, with good binding energy (DS values: -12.3 to -14.4 kcal/mol) and acceptable RMSD values (0.77-1.75 Å). In general, these identified compounds processed drug properties and were non-toxic for human use, based on Lipinski's rule of five and ADMET analyses.

Harpephyllum caffrum fruit (wild plum) facilitates glucose uptake and modulates metabolic activities linked to neurodegeneration in isolated rat brain: An in vitro and in silico approach

Alteration in brain glucose metabolism due to glucose uptake reduction has been described in the onset of certain neurodegenerative disorders. This study determined Harpephyllum caffrum fruit's potential ability to improve glucose uptake and its modulatory effects on intrinsic antioxidant, glucogenic, cholinergic, and nucleotide-hydrolyzing enzyme activities in isolated rat brain. Consequently, the bioactive compounds of the fruits were identified with LC-MS. The fruit significantly improved brain glucose uptake following coincubation with glucose and brain tissue. The fruit extract also elevated GSH level, SOD, catalase, glycogen phosphorylase, and ENTPDase activities while simultaneously suppressing NO and malonaldehyde levels and fructose-1,6-bisphosphatase, ATPase, acetylcholinesterase and butyrylcholinesterase activities. LC-MS analysis revealed S-methylcysteine sulfoxide, dihydroquercetin, 3,4-dimethyl-2,5-bis(3,4,5-trimethoxyphenyl) tetrahydrofuran (MTHF), nobiletin, puerarin, quercetin 3-rutinoside, 8-D-glucosyl-4',5,7-trihydroxyflavone, asperulosidic acid, 1,2,4,6-tetragalloylglucose, and phellamurin. This study suggests the neuroprotective effects of H. caffrum fruit due to its ability to enhance glucose uptake, attenuate glucose-induced oxidative stress while modulating glucogenic, cholinergic, and nucleotide-hydrolyzing enzyme activities in normal brain tissues. PRACTICAL APPLICATIONS: Available scientific evidence describes oxidative stress as one of the physiological processes contributing to aging-associated neurodegeneration in humans. In this regard, commonly consumed natural products from plants have attracted much interest due to their ability to mitigate redox imbalance-related pathologies that affect various organs in the body such as the brain. Harpephyllum caffrum or bush mango is an evergreen plant native to the South African vegetation. The fruit from the plant is consumed locally as food or specifically for improving the nutritional quality of meals as deserts or condiments. While previous findings described the high antioxidant properties of the fruits, this study reported possible mechanisms via which the plant may exhibit ameliorative effects against oxidative stress-related neurological disorders in the brain. Hence, findings from the current work present another justification for the significance of fruits as a safer nutraceutical alternative for therapy in neurological disease management.

Evaluation of selected carotenoids of Lycopersicon esculentum variants as therapeutic targets for 'Alzheimer's disease: an in silico approach

The seriousness and menace of the worldwide weight of 'Alzheimer's disease have been related to a few factors, which incorporate antioxidant system depletion, mutation of proteins, and high expression of cholinesterases due to aging, environmental influence, diet, infectious agents, and hormonal imbalance. Overexpression of cholinesterases has been emphatically connected to 'Alzheimer's disease because of the unreasonable hydrolysis of acetylcholine and butyrylcholine. Certain plant phytochemicals, for example, beta-carotenoids, lutein, neoxanthin, and viola-xanthine from Lycopersicon esculentum Mill. Var. esculentum (ESC) and Lycopersicon esculentum Mill. Var. cerasiforme (CER) has been utilized altogether as a therapeutic candidate for the treatment of 'Alzheimer's disease. Therefore, this research sought to investigate the drug-likeness of the individual carotenoids as detailed for cholinesterase inhibition in the treatment of 'Alzheimer's disease. Four potential cholinesterase inhibitors from ESC and CER were retrieved from the PubChem database. Investigation of their drug-likeness, toxicity prediction, molecular docking, and dynamic simulations were carried out using Molinspiration, PreADMET V.2.0, Patchdock server, and Schrodinger Maestro software respectively. Neoxanthin was ranked the safest with a greater tendency to inhibit the cholinesterases with high binding affinity. In addition, its stability after simulation in a mimicked biological environment suggests its relevance as a potential drug candidate for the treatment of 'Alzheimer's disease through the inhibition of cholinesterases.

Effect of storage on plant biostimulant and bioactive properties of freeze-dried Chlorella vulgaris biomass

Microalgae are potential plant biostimulants and biocontrol agents. A major hurdle towards their commercialization is the production of large volumes of biomass at the correct time of year. Secondary metabolites are unstable and the "shelf-life" of bioactive microalgal biomass needs to be investigated. The aim of the study was to investigate the effects of storage conditions on freeze-dried microalgae to determine how long the biomass retained its growth promoting and bioactive properties under various temperature and light conditions. Chlorella vulgaris biomass was stored in the dark at - 70 °C, 10 °C, and 25 °C and in the light at 25 °C. Samples were tested every 3-4 months for 15 months. Storage time significantly influenced the rate of change in the bioactivity in the C. vulgaris biomass with storage temperature also having some effect. Rooting activity decreased in the mungbean rooting assay over time up to 12 months and then increased slightly. Antimicrobial activity increased against Staphylococcus aureus and Escherichia coli for up to 12 months and then declined. Antioxidant activity measured in the DPPH assay remained relatively stable for up to 12 months and then significantly decreased with longer storage. The change in bioactivity over time was attributed to the gradual breakdown of the rigid cell wall of C. vulgaris, thereby improving extraction efficiency but exposing the secondary metabolites to oxygen, thus quickening their degradation. Biomass produced for commercial purposes requires preliminary validation as the results of the present study showed that bioactive compounds are susceptible to degradation over time.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10811-021-02596-9.

Three new alkaloids from Portulaca oleracea L. and their bioactivities

Three novel alkaloids, named oleracone L (1), portulacatone B (2), and portulacatal (3), were isolated from P. oleracea L.. The structures were determined using UV, IR, 1D and 2D NMR spectroscopy and UHPLC-ESI-QTOF/MS. The three compounds in a dose-dependent manner significantly reduced the secretion of IL-1β in the lipopolysaccharide-stimulated macrophages RAW 264.7 cell culture supernatant, moreover, exhibited the anticholinesterase activities.

An Insight into Kiwiberry Leaf Valorization: Phenolic Composition, Bioactivity and Health Benefits

During kiwiberry production, different by-products are generated, including leaves that are removed to increase the fruit’s solar exposure. The aim of this work was to extract bioactive compounds from kiwiberry leaf by employing microwave-assisted extraction (MAE). Compatible food solvents (water and ethanol) were employed. The alcoholic extract contained the highest phenolic and flavonoid contents (629.48 mg of gallic acid equivalents (GAE) per gram of plant material on dry weight (dw) (GAE/g dw) and 136.81 mg of catechin equivalents per gram of plant material on dw (CAE/g dw), respectively). Oppositely, the hydroalcoholic extract achieved the highest antioxidant activity and scavenging activity against reactive oxygen and nitrogen species (IC₅₀ = 29.10 μg/mL for O₂^•−, IC₅₀ = 1.87 μg/mL for HOCl and IC₅₀ = 1.18 μg/mL for ^•NO). The phenolic profile showed the presence of caffeoylquinic acids, proanthocyanidin, and quercetin in all samples. However, caffeoylquinic acids and quercetin were detected in higher amounts in the alcoholic extract, while proanthocyanidins were prevalent in the hydroalcoholic extract. No adverse effects were observed on Caco-2 viability, while the highest concentration (1000 µg/mL) of hydroalcoholic and alcoholic extracts conducted to a decrease of HT29-MTX viability. These results highlight the MAE potentialities to extract bioactive compounds from kiwiberry leaf.

Potential Anti-Acetylcholinesterase Activity of Cassia timorensis DC

Seventeen methanol extracts from different plant parts of five different Cassia species, including C. timorensis, C. grandis, C. fistula, C. spectabilis, and C. alata were screened against acetylcholinesterase (AChE). C. timorensis extracts were found to exhibit the highest inhibition towards AChE whereby the leaf, stem, and flower methanol extracts showed 94-97% inhibition. As far as we are aware, C. timorensis is one of the least explored Cassia spp. for bioactivity. Further fractionation led to the identification of six compounds, isolated for the first time from C. timorensis: 3-methoxyquercetin (1), benzenepropanoic acid (2), 9,12,15-octadecatrienoic acid (3), β-sitosterol (4), stigmasterol (5), and 1-octadecanol (6). Compound 1 showed moderate inhibition towards AChE (IC50: 83.71 μM), while the other compounds exhibited poor to slightly moderate AChE inhibitory activity. Molecular docking revealed that the methoxy substitution of 1 formed a hydrogen bond with TYR121 at the peripheral anionic site (PAS) and the hydroxyl group at C5 formed a covalent hydrogen bond with ASP72. Additionally, the OH group at the C3' position formed an interaction with the protein at the acyl pocket (PHE288). This possibly explains the activity of 1 in blocking the entry of acetylcholine (ACh, the neurotransmitter), thus impeding the hydrolysis of ACh.

Inhibition of CYP2E1 and activation of Nrf2 signaling pathways by a fraction from Entada africana alleviate carbon tetrachloride-induced hepatotoxicity

Entada africana is used in non-conventional medicine for the management of liver ailments. A fraction, designated EaF10 (methylene chloride/methanol 90:10, v/v) with promising hepatoprotective activity has been isolated. Since the mechanisms underlying EaF10 hepatoprotective action remain unknown, this study was undertaken to investigate the anti-hepatotoxic mechanism of the fraction against carbon tetrachloride (CCl₄)-induced hepatotoxicity and its antioxidant properties. Antioxidant activities of EaF10 were assessed through four chemical antioxidant assays and its anti-hepatotoxic effect evaluated in vivo and in vitro by post-treatment (25 or 100 mg/Kg) or co-treatment (6.25–100 μg/mL) in CCl₄-intoxicated mice and normal human liver cells line L-02 hepatocytes respectively; and biochemical and molecular parameters assessed respectively by spectrophotometry, and by quantitative real-time polymerase chain reaction and western blot analysis. EaF10 exhibited strong antioxidant activities correlated with its polyphenol content. Serum levels of alanine/aspartate aminotransferase (AST/ALT) and nitrite oxide, liver contents of glutathione (GSH) protein carbonylation and malondialdehyde (MDA), liver activities of catalase (CAT), glutathione-S-transferase (GST) and superoxide dismutase (SOD) and cell viability showed the anti-hepatotoxic effect of EaF10, supported by histopathological observations. The fraction decreased the protein level of Cytochrome P450 2E1 (CYP2E1) and Kelch-like ECH-associated protein-1 (Keap-1), induced nuclear translocation of Nuclear factor-erythroid 2-related factor-2 (Nrf2) coupled to an increase of the mRNA levels of CAT, SOD1 and GST in CCl₄-intoxicated L-02 hepatocytes. These findings evidenced that the studied plant fraction possesses a strong antioxidant capacity and prevents CCl₄-induced hepatotoxicity, likely through inhibition of CYP2E1 and activation of the Nrf2 signaling pathway.

Evaluation of bioactive compounds, free radical scavenging and anticancer activities of bulb extracts of Boophone disticha from Eastern Cape Province, South Africa

Boophone disticha (B. disticha) is a bulbous tropical and subtropical flowering plant widespread in Africa, which is frequently used to treat several human ailments. Until the present, there is no scientific validation on the biological activity of this plant from the Eastern Cape Province of South Africa and as a result, this study aimed to assess the bioactive compounds, free radicals scavenging and anticancer potentials of crude bulb extracts (chloroform, acetone, and ethanol) of Boophone disticha obtained from this geographical location. Standard biochemical techniques and Gas-chromatography mass spectrometry (GCMS) analysis were used to pinpoint the bioactive compounds in the crude extracts sequel to their antioxidant potentials against radicals such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), hydrogen peroxide and nitric oxide as well as their ferric ion reducing power. In addition, their cytotoxicity effects against Human cervix adenocarcinoma (HeLa) cells were assessed as an in vitro model for anticancer. The phytochemical evaluation of the crude extracts showed the presence of phenolics, flavonoids, and alkaloids. GCMS profiles confirmed the presence of some bioactive compounds in the crude extracts of B. disticha that could be responsible for their biological activities. The plant extracts possessed considerable antioxidant activity and exhibited dose-dependent radicals’ inhibition from all assays carried out. Furthermore, the cytotoxicity effects against HeLa cells recorded inhibition concentration (IC₅₀) of 1.5, 1.6, and 1.9 µg/mL for acetone, chloroform, and ethanolic extracts of B. disticha, respectively. Findings from the present study suggest that B. disticha could be a good prospective source of antioxidant and anticancer agents. Therefore, further research on the isolation and purification of compounds from these extracts are indispensable.

An In Vitro and In Vivo Cholinesterase Inhibitory Activity of Pistacia khinjuk and Allium sativum Essential Oils

Objectives

Alzheimer’s disease (AD), an overwhelming neurodegenerative disease, has deleterious effects on the brain that consequently causes memory loss and language impairment. This study was intended to investigate the neuroprotective activity of the two essential oils (EOs) from Iranian Pistacia khinjuk (PK) leaves and Allium sativum (AS) cloves against β-Amyloid 25–35 (Aβ25-35) induced elevation of cholinesterase enzymes in AD.

Methods

The EOs of PK (PKEO) and AS (ASEO) were prepared and analyzed in terms of extraction yield, phenolic content, and cholinergic markers in vitro. Moreover, both were administered orally to adult male Wistar rats at concentrations of 1, 2, and 3%. The inhibitory potential of PKEO and ASEO was compared with Donepezil (0.75 mg/kg) against the high activities of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes.

Results

PKEO reached an inhibition rate of 83.6% and 81.4% against AChE and BChE, respectively. ASEO had lower anti-cholinesterase activity (65.4% and 31.5% for the inhibition AChE and BChE). PKEO was found to have more phenolic content than ASEO. A significantly positive correlation was observed between the total phenolics and anti-cholinesterase potential. In rats, both EOs decreased the enzyme activity in a concentration-dependent manner. As compared with Donepezil, the significant difference in the AChE and BChE inhibition occurred as rats were treated with PKEO 3% (p < 0.05).

Conclusion

It could be concluded that PKEO and ASEO are potent inhibitors of AChE and BChE in rats that hold promise to be used for the treatment of AD.

Antifungal and anti-mycotoxigenic activity of selected South African medicinal plants species

Antifungal and anti-mycotoxigenic activity of 25 acetone leaf extracts of South African medicinal plants with potent antioxidant activity were investigated against three phytopathogenic fungal strains. The extracts exhibited varying degrees of in vitro anti-mycotoxigenic effect against Fusarium verticillioides, Aspergillus flavus and Aspergillus ochraceous. Markhamia obtusifolia (Baker) Sprague exhibited the lowest minimum inhibitory concentration (MIC) values as low as 0.08 mg/ml against Aspergillus flavus and Furasium verticilloides at both 24 and 48 hr incubation period, while Curtisia dentata exhibited similar MIC value against Aspergillus ochraceous. Curtisia dentata further yielded the highest total activity of 1583 ml/g against Aspergillus ochraceous at 24 and 48 hr incubation period. In the mycelial growth inhibition (MGI) evaluation, Fusarium verticilloides was more sensitive to plants extracts, while Kirkia wilmsii exhibited highest MGI of 50.08% against Fusarium verticilloides on the 6th day of incubation. Five acetone extracts from Acokanthora oppositifolia, Bauhinia galpinii, Combretum caffrum, Ricinus communis and Solanum aculeastrum exhibited lowest IC50 value of 0.01 mg/ml against (2,2'-azinobis-3-ethylbenzthiazoline-6-suphonic acid (ABTS). Curtisia dentata and Markhamia obtusifolia extracts were further subjected to gas chromatography mass-spectrophotometry (GC-MS) analysis. Curtisia dentata revealed the presence of triterpenoid compounds, β-amyrin (53.30%) and α-amyrin (6.42%), while Markhamia obtusifolia yielded the presence of neophytadiene (4.38%) and palmitic acid (3.61%) The results suggest that natural products from plants may well be used as possible substitutes for synthetic fungicides. Given the antifungal and antioxidant potential of the selected plants, they may have potential as possible leads for the development of biofungicides that may well prevent oxidation related food spoilage.

Acetylcholinesterases from Leaf-Cutting ant Atta sexdens: Purification, Characterization, and Capillary Reactors for On-Flow Assays

Acetylcholinesterase (AChE) is responsible for catalyzing the hydrolysis of the neurotransmitter acetylcholine (ACh) leading to acetate and choline (Ch) release. The inhibition of AChE produces a generalized synaptic collapse that can lead to insect death. Herein we report for the first time the isolation of two AChEs from Atta sexdens which were purified by sulphate ammonium precipitation followed by ion exchange chromatography. AsAChE-A and AsAChE-B enzymes have optimum pH of 9.5 and 9.0 and higher activities in 30/50°C and 20°C, respectively, using acetylthiocholine (ATCh) as substrate. Immobilized capillary enzyme reactors (ICERs) were obtained for both enzymes (AsAChE-A-ICER and AsAChE-B-ICER) and their activities were measured by LC-MS/MS through hydrolysis product quantification of the natural substrate ACh. The comparison of activities by LC-MS/MS of both AChEs using ACh as substrate showed that AsAChE-B (free or immobilized) had the highest affinity. The inverse result was observed when the colorimetric assay (Elman method) was used for ATCh as substrate. Moreover, by mass spectrometry and phylogenetic studies, AsAChE-A and AsAChE-B were classified as belonging to AChE-2 and AChE-1 classes, respectively.

Phytochemical analysis, antioxidant and antimicrobial activity of wild and in vitro derived plants of Ceropegia thwaitesii Hook - An endemic species from Western Ghats, India

Ceropegia thwaitesii Hook (Asclepiadaceae), an endemic plant species, due to habitat destruction and over exploitation has a very restricted distribution in the Western Ghats of Tamil Nadu, India. The present wrok aimed to determine the chemical composition, the total phenolic (TPC), flavonoid (TFC) and tannin content (TEC), and to assess the antioxidant properties of various extracts of in vivo plants (IVP) and in vitro regenerated plants (IRP) of C. thwaitesii. Some phenolic compounds like gallic acid, cathechol, vanillin and salicylic acid were identified and quantified by HPLC. All the extracts possessed relevant radical scavenging activity on DPPH, Superoxide radical scavenging activity, and Nitric oxide radicals as well as total antioxidant ability. DPPH assay of in vitro methanol stems extracts and ethanol leaves extracts revealed the best antioxidant properties with important IC50 values of 0.248 ± 0.45 µg/mL and 0.397 ± 0.67 µg/mL, respectively, whereas in vivo chloroform stems extracts showed a lower antioxidant activity (IC50 of 10.99 ± 0.24 µg/mL). The IRP methanol extracts of stem and leaves had good inhibitory activity against all tested microorganisms in a dose-dependent manner. These results suggested that in vitro raised plants of C. thwaitesii are an excellent source of antioxidant compounds to be exploited on an industrial level as food additive.

Identification and characterization of potential bioactive compounds from the leaves of Leucosidea sericea

ETHNOPHARMACOLOGICAL RELEVANCE

Leucosidea sericea is a southern African tree used for treating different diseases including microbial infections and inflammatory-related conditions.

AIM OF THE STUDY

To isolate and identify the chemicals in Leucosidea sericea which possibly account for the diverse therapeutic effects of the species.

MATERIALS AND METHODS

Leaf material was extracted using 20% methanol and subsequently partitioned with different solvents (hexane, dichloromethane, ethyl acetate and butanol). Resultant fractions were subjected to bioactive (antimicrobial)-guided isolation and the structural elucidation was conducted using NMR (1D and 2D) spectroscopic methods. Given the broad uses of Leucosidea sericea in traditional medicine, the extract, fractions and isolated compounds were evaluated in five (5) biological assays in vitro (antimicrobial, antioxidant, acetylcholinesterase (AChE) and anti-inflammatory inhibition as well as cytotoxicity effect).

RESULTS

As the most active fractions, from ethyl acetate yielded 5,7-dihydroxychromone (1); 1-hydroxy-2-oxopomolic acid (2); 3,5,7,3´,4´-pentahydroxyflavone (3) and Tiliroside (4). For the first time, these four (4) compounds were isolated from leaves of Leucosidea sericea. These aforementioned compounds demonstrated broad-spectrum antibacterial activity (1.95-125 µg/mL) and noteworthy antifungal (3.9-250 µg/mL) potential. In addition to its noteworthy antimicrobial activity, compound 3 also demonstrated significant antioxidant (EC₅₀ = 14 µg/mL in DPPH assay) and anti-inflammatory (inhibited the level of ELAM by approximately 36% and decreased also the viability of endothelial cells) activities in vitro. Overall, AChE inhibition activity and cytotoxic response was generally weak for the extracts, fractions and isolated compounds.

CONCLUSION

The pool of chemicals in Leucosidea sericea were enriched with the isolation and identification of four (4) compounds obtained from the leaf extract. Among these compounds, the significant antimicrobial activity of compound 3 provides strong evidence that support the use of Leucosidea sericea for microbial-related infections in folk medicine.

Lafoensia pacari A. St.-Hil.: Wound healing activity and mechanism of action of standardized hydroethanolic leaves extract

ETHNOPHARMACOLOGICAL IMPORTANCE

Lafoensia pacari A. St.-Hil., (Lythraceae) is a native tree of Brazilian Cerrado and commonly known in Brazil as "mangava-brava". Its leaves are used in Brazilian folk medicine in wound healing, cutaneous mycoses, and in the treatment of gastritis and ulcers.

AIM OF THE STUDY

The present study was designed to evaluate the wound healing activity and mechanism of action of the hydroethanolic extract of Lafoensia pacari A. St.-Hil. leaves (HELp), and to advance in its chemical profiling.

MATERIALS AND METHODS

HELp was prepared by maceration in 70% hydroethanolic solution (1:10, w/v). The phytochemical analyses were investigated using colorimetry and electrospray ionization/mass spectrometric detection (ESI-MSⁿ). Its in vitro cytotoxicity was evaluated in CHO-K1 and L929 cells, while the in vivo acute toxicity was performed in mice. The potential in vivo wound healing activity was assessed using excision and incision rat models and histopathology of the wounded skin (excision model) was carried out. The in vitro wound healing activity of HELp was demonstrated by scratch assay in L-929 cells, by measuring proliferation/migration rate and p-ERK 1/2 protein expression using western blot analysis. HELp's in vivo anti-inflammatory activity was evaluated by lipopolysaccharide (LPS) induced peritonitis in mice, along with the determination of nitric oxide (NO) and cytokines (TNF-α and IL-10) in the peritoneal lavages. Its potential in vitro antibacterial activity was performed using microbroth dilution assay, while in vitro antioxidant activities was by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and ferric reducing antioxidant power (FRAP) assays.

RESULTS

The phytochemical analysis of HELp revealed the presence of polyphenols with ellagic acid, punicalagin, punicalin, kaempferol, quercetin-3-O-xylopyranoside and quercetin-3-O-rhamnopyranoside being the most prominent. HELp showed no toxicity on CHO-k1 and L929 cell lines. Topical treatment with HELp (10 and 30 mg/g of gel) presented increased rates of wound contraction at all the days evaluated with complete wound re-epithelialization at 22.0 ± 1.5 (p < 0.05) and 21.7 ± 1.6 (p < 0.01) days, respectively. Topical application of HELp (10, 30 or 100 mg/g of gel) in incised wounds caused an increase in tensile break strength at all concentrations resulting in moderate re-epithelialization and neovascularization, increased cell proliferation an accelerated remodeling phase of the wound, in a manner comparable to standard drug (Madecassol^®, 10 mg/g). In the scratch assay with L929 cells, HELp (0.1 and 0.03 mg/mL) and PDGF (5 ng/mL) resulted in the increased proliferation/migration rate of fibroblasts and higher expression of p-ERK 1/2 protein. In LPS-induced peritonitis, HELp (100 and 200 mg/kg p.o.) decreased total leukocyte migration, comparable to the dexamethasone (0.5 mg/kg p.o.). In RAW 264.7 macrophages activated by LPS, HELp produced anti-inflammatory activity dependent on increased concentrations of IL-10, reduction in NO production, without altering the TNF-α levels. HELp also presented potent antioxidant activity in the DPPH and FRAP, but lacks in vitro antibacterial activity.

CONCLUSION

The present study results support the popular use of the leaves of L. pacari in the treatment of wounds. Its wound healing activity is multi-targeted and involves inhibition of the proliferative and anti-inflammatory phases, antioxidant and positive modulation of the remodeling phase that might be involved different secondary metabolites, with emphasis on the ellagic acid, punicalagin, punicalin, kaempferol, quercetin-3-O-xylopyranoside and quercetin-3-O-rhamnopyranoside.

Traditional and ethnobotanical dermatology practices in Africa

More than 80% of the global population depends on traditional medicine for their basic primary health care needs. Africa has a well-established history of botanicals use. These include a vast array of compounds that can be used to treat various skin-related conditions. The rationale for the use of traditional medicine in skincare stems from the physical effects these compounds have on skin, such as the ability to control bleeding and speed up wound healing, as well as the potential to treat burns and other disorders of pigmentation. Most African traditional healers employ decoctions and infusion methods in medicinal plant preparations; the former entails boiling of the whole or parts of the plant in water or other solvents to extract the active ingredients. Infusions involve immersion of the plant in hot or cold water for some time, followed by topically application to the affected skin area. The cosmetic skincare products are formulated to protect, enhance, and preserve the skin in its healthiest state to maintain its barrier function, thus protecting the human body. This review examines a number of botanicals that are used across Africa and the phytochemical actives that are responsible for skincare.

Characterization of New Bioactive Enzyme Inhibitors from Endophytic Bacillus amyloliquefaciens RWL-1

Endophytic bacteria are known to produce a wide array of bioactive secondary metabolites with beneficial effects on human health. In the current study, a novel endophytic bacterial strain, Bacillus amyloliquefaciens RWL-1, was isolated from the seeds of Oryza sativa. Initially, the crude extract of RWL-1 was assessed for potential biological effects of enzyme inhibition and cytotoxicity and was found to exhibit a broad spectrum inhibition for α-glucosidase (37 ± 0.09%) and urease (49.4 ± 0.53%). The screening results were followed by bioassay-guided isolation of secondary metabolite(s) from RWL-1. Extensive chromatographic and spectrophotometry analyses revealed the presence of compound 1 (S)-2-hydroxy-N-((S)-1-((S)-8-hydroxy-1-oxoisochroman-3-yl)-3-methylbutyl)-2-((S)-5-oxo-2,5-dihydrofuran-2-yl)acetamide. Further bioassays of compound 1 showed significant inhibition of α-glucosidase (52.98 ± 0.8%) and urease (51.27 ± 1.0%), compared with positive control values of 79.14 ± 1.9% and 88.24 ± 2.2%, and negative controls (0.08 ± 0.1% and 0.05 ± 0.01%), respectively. The current study suggests that bacterial endophytes are a rich source of novel bioactive compounds with high therapeutic value.

Biochemical Constituents and in Vitro Antioxidant and Anticholinesterase Potential of Seeds from Native Korean Persimmon Genotypes

In the current study, the functional and biochemical potential of the seeds of four persimmon cultivars (PC1, PC2, PC3 and PC4) and their role against oxidative stress and acetylcholinesterase (AChE) inhibition were evaluated. In terms of biochemical compositions, free amino acids, fatty acids and organic acids analysis was performed. The free amino acids ranged from 2617.31 (PC2) to 3773.01 μg∙g(-1) dry weight (PC4). Oleic acid and linoleic acid were the principal fatty acids, which were significantly higher in PC4 and PC1, respectively. PC4 presented the highest amount of organic acid content (4212 mg∙kg(-1)), whereas PC2 presented the lowest (2498 mg∙kg(-1)). PC2 contained higher total phenolic content and flavonoid content, whereas PC3 had the lowest amount as compared to other cultivars. The in vitro DPPH, ABTS and superoxide anion radicals scavenging activity increased in a dose-dependent manner, whereas PC2 showed significantly higher scavenging activities as compared to PC1, PC2 and PC4 types. In the case of AChE inhibition, PC4 showed a moderate activity (67.34% ± 1.8%). In conclusion, the current findings reveal that the studied persimmon seeds cultivars are a source of bioactive natural antioxidants and AChE inhibitors. Such natural products could be employed in pharmaceutical and food industries, whilst can also be considered for the treatment of neurodegenerative diseases such as Alzheimer's.

An ethnobotanical survey of medicinal plants used by communities of Northern Kordofan region, Sudan

ETHNOPHARMACOLOGICAL RELEVANCE

The present study provides significant ethnopharmacological information on plant species used in North Kordofan region, western Sudan. The study was undertaken with an aim to document the medicinal uses of the species known to some Northern Kordofan communities.

MATERIAL AND METHODS

The study was conducted between 2012 and 2013. The plants were identified and voucher specimens prepared. Information was collected by means of semi-structured interviews with 258 informants (195 men and 63 women). In addition, the use value (UV) of the species was determined and the informant consensus factor (ICF) was calculated for the medicinal plants researched in the study. Further analysis was carried out to compare results with previous studies from the study area and other regions of Sudan.

RESULTS

A total of 44 plant species representing 24 families were found to be commonly used in the treatment of 73 different human health problems. The families most represented were Leguminosae (18%), Caesalpiniaceae (9%), Malvaceae (9%), Asclepiadaceae (6.8%) and Combretaceae (6.8%). The highest number of plant species are used against digestive system disorders (23 species) followed by microbial infections (21 species) and dermatology (19 species). Among all the plant parts leaves (20%), roots (19%), fruits and bark (14% each) were the most preferred plant parts used by the informants. There was strong agreement among the informants as to the usages of the plants (informant consensus factor 0.63-0.93). The most important plants on the basis of use-value were Acacia nilotica, Acacia seyal, Balanites aegyptiaca, Cassia occidentalis, Cassia senna, Guiera senegalensis and Tamarindus indica.

CONCLUSION

This study has helped to document information that may otherwise be lost to future generations. This is the first ethnobotanical study in which statistical calculations about plants are carried out by means of the ICF and UV methods in the study area. Plants with high ICF and UV values should be subjected for further phytochemical and pharmacological investigation for scientific validation.

Antioxidant fractions of Khaya grandifoliola C.DC. and Entada africana Guill. et Perr. induce nuclear translocation of Nrf2 in HC-04 cells

The in vitro antioxidant properties, cytoprotective activity, and ability to induce nuclear translocation of nuclear factor E2-related factor-2 (Nrf-2) of five solvent fractions of the methylene chloride/methanol (1:1 v/v) extract of Khaya grandifoliola (Meliaceae) and Entada africana (Fabaceae) were evaluated. Five antioxidant endpoints were used in the antioxidant activity investigation. The total phenolic content of the fractions was assessed as to the Folin-Ciocalteu method and the profile of interesting fractions analyzed by high-performance liquid chromatography (HPLC). The cytoprotective activity of fractions was determined by H2O2-induced oxidative stress in HC-04 cells by measuring lactate dehydrogenase (LDH) leakage into culture medium. HC-04 cells were used to investigate the ability to induce nuclear translocation of Nrf2. For both plants, the methylene chloride/methanol (90/10; v/v) fraction (F10), methylene chloride/methanol (75/25; v/v) (F25), and the methanolic fraction (F100) were found to have the highest total polyphenol content and exhibited high antioxidant activity strongly correlated with total polyphenol content. The cytoprotective activity of fraction F25 from both plants was comparable to that of quercetin (3.40 ± 0.05 μg/mL), inhibiting LDH leakage with a low half inhibition concentration (IC50) of 4.05 ± 0.03 and 3.8 ± 0.02 μg/mL for K. grandifoliola and E. africana, respectively. Lastly, fraction F25 of K. grandifoliola significantly (P < 0.05) induced nuclear Nrf2 translocation by sixfold, whereas that from E. africana and quercetin was only twofold. The results indicate for the first time that fraction F25 of the studied plants is more antioxidant and cytoprotective and induces nuclear translocation of Nrf2 in a human hepatocyte cell line.

Dissecting the role of two cytokinin analogues (INCYDE and PI-55) on in vitro organogenesis, phytohormone accumulation, phytochemical content and antioxidant activity

There is a continuous search for new chemical entities to expand the collection of suitable compounds to increase the efficiency of micropropagation protocols. Two cytokinin (CK) analogues, 2-chloro-6-(3-methoxyphenyl)aminopurine (INCYDE) and CK antagonist 6-(2-hydroxy-3-methylbenzylamino)purine (PI-55) were used as a tool to elucidate the auxin-CK crosstalk under in vitro conditions in the medicinally important plant, Eucomis autumnalis subspecies autumnalis. These compounds were tested at 0.01, 0.1 and 10 μM alone as well as in combination with benzyladenine (BA) and naphthaleneacetic acid (NAA). The organogenesis, phytohormone content, phytochemical and antioxidant response in 10 week-old-in vitro regenerated E. autumnalis subspecies autumnalis was evaluated. INCYDE generally favoured shoot regeneration while the effect of PI-55 was more evident in root proliferation. Overall, INCYDE promoted the accumulation of higher concentrations and varieties of endogenous CK relative to the PI-55 treatments. In contrast, higher concentration of indole-3-acetic acid and 2-oxindole-3-acetic acid were generally observed in PI-55-supplemented cultures when compared to plantlets derived from INCYDE. Both CK analogues (individually and in-conjunction with exogenously applied PGRs) significantly influenced the phytochemicals and consequently the antioxidant potential of the in vitro regenerants. These results provided insight on how to alleviate root inhibition, a problem which causes considerable loss of several elite species during micropropagation.

Anticholinesterase and antioxidant investigations of crude extracts, subsequent fractions, saponins and flavonoids of atriplex laciniata L.: potential effectiveness in Alzheimer's and other neurological disorders

Background

Atriplex laciniata L. was investigated for phenolic, flavonoid contents, antioxidant, anticholinesterase activities, in an attempt to explore its effectiveness in Alzheimer’s and other neurological disorders. Plant crude methanolic extract (Al.MeF), subsequent fractions; n-hexane (Al.HxF), chloroform (Al.CfF), ethyl acetate (Al.EaF), aqueous (Al.WtF), Saponins (Al.SPF) and Flavonoids (Al.FLVF) were investigated for DPPH, ABTS and H₂O₂ free radical scavenging activities. Further these extracts were subjected to acetylcholinesterase (AChE) & butyrylcholinesterase (BChE) inhibitory activities using Ellman’s assay. Phenolic and Flavonoid contents were determined and expressed in mg Gallic acid GAE/g and Rutin RTE/g of samples respectively.

Results

In DPPH free radicals scavenging assay, Al.FLVF, Al.SPF and Al.MeF showed highest activity causing 89.41 ± 0.55, 83.37 ± 0.34 and 83.37 ± 0.34% inhibition of free radicals respectively at 1 mg/mL concentration. IC₅₀ for these fractions were 33, 83 and 82 μg/mL respectively. Similarly, plant extracts showed high ABTS scavenging potential, i.e. Al.FLVF (90.34 ± 0.55), Al.CfF (83.42 ± 0.57), Al.MeF (81.49 ± 0.60) with IC₅₀ of 30, 190 and 70 μg/ml respectively. further, H₂O₂ percent scavenging was highly appraised in Al.FLVF (91.29 ± 0.53, IC₅₀ 75), Al.SPF (85.35 ± 0.61, IC₅₀ 70) and Al.EaF (83.48 ± 0.67, IC₅₀ 270 μg/mL). All fractions exhibited concentration dependent AChE inhibitory activity as; Al.FLVF, 88.31 ± 0.57 (IC₅₀ 70 μg/mL), Al.SPF, 84.36 ± 0.64 (IC₅₀ 90 μg/mL), Al.MeF, 78.65 ± 0.70 (IC₅₀ 280 μg/mL), Al.EaF, 77.45 ± 0.46 (IC₅₀ 270 μg/mL) and Al.WtF 72.44 ± 0.58 (IC₅₀ 263 μg/mL) at 1 mg/mL. Likewise the percent BChE inhibitory activity was most obvious in Al.FLVF 85.46 ± 0.62 (IC₅₀ 100 μg/mL), Al.CfF 83.49 ± 0.46 (IC₅₀ 160 μg/mL), Al.MeF 82.68 ± 0.60 (IC₅₀ 220 μg/mL) and Al.SPF 80.37 ± 0.54 (IC₅₀ 120 μg/mL).

Conclusions

These results stipulate that A. laciniata is enriched with phenolic and flavonoid contents that possess significant antioxidant and anticholinestrase effects. This provide pharmacological basis for the presence of compounds that may be effective in Alzheimer’s and other neurological disorders.

Phenolic compounds in edible species of the Anacardiaceae family – a review

Members of the Anacardiaceae (cashew family) are of economic importance and contain a diverse range of phenolic compounds.

Plant regeneration and biochemical accumulation of hydroxybenzoic and hydroxycinnamic acid derivatives in Hypoxis hemerocallidea organ and callus cultures

Micropropagation of Hypoxis hemerocallidea Fisch. and C.A. Mey was used as a model system to study the influence of cytokinins (CKs) on plant regeneration and biochemical accumulation of hydroxybenzoic and hydroxycinnamic acid derivatives in organ and callus cultures and their antioxidant activity. Fourteen free phenolic acids were detected using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) while antioxidant activity was evaluated using oxygen radical absorbance capacity (ORAC) and 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity. Cytokinins had a significant effect on the biochemical accumulation of hydroxybenzoic and hydroxycinnamic acid derivatives in H. hemerocallidea organ cultures. In particular, meta-topolin-treated organ cultures produced high concentrations of gallic, protocatechuic, gentisic, p-hydroxybenzoic, m-hydroxybenzoic, salicylic, chlorogenic and trans-cinnamic acids. The isoprenoid CK, N(6)-(2-isopentenyl)-adenine significantly increased the accumulation of hydroxycinnamic acid derivatives, namely, caffeic, p-coumaric, sinapic and ferulic acids. Cytokinin-treated organ cultures exhibited a significant increase in antioxidant activity, particularly in the ORAC model. In callus cultures, CKs decreased the concentrations of hydroxycinnamic acid derivatives and antioxidant activity when compared to the control. Overall, both CK type and concentration had a significant effect on plant regeneration, callus proliferation, biochemical accumulation of free phenolic acids and antioxidant activity of the resultant extracts.

Analyses of the essential oil from Bunium persicum fruit and its antioxidant constituents

This study was aimed to analyze and identify the antioxidant constituents of the essential oil of Bunium persicum (Apiaceae) fruit. The essential oil was obtained by hydrodistillation and analyses by GC-FID and GC-MS. The essential oil was tested for antioxidant capacity in DPPH radical scavenging and linoleic acid/β-carotene assays. The TLC-bioautography method based on DPPH radical assay and GC analyses were carried out to characterize the major antioxidant compounds in the essential oil. GC analyses showed the presence of sixteen compounds with p-cymene (31.1%), cuminaldehyde (22.2%), and γ-terpinene (11.4%) as the main components in the essential oil. The oil exhibited good radical scavenging [IC50 (DPPH·) = 4.47 (3.96 - 5.05) mg/mL] and antilipid peroxidation [IC50 (β-carotene bleaching) = 0.22 (0.16 - 0.31) mg/mL] activities. The TLC tests resulted in identification of cuminaldehyde, p-cymene-7-ol, and cuminyl acetate as the main constituents of the active oil fraction.

Anti-biofilm activity of Marula - a study with the standardized bark extract

ETHNOPHARMACOLOGICAL RELEVANCE

Marula (Sclerocarya birrea; family - Anacardiaceae) is an African plant, which enjoys wide socio-economic importance particularly in southern part of Africa. The fruits are consumed as food and also as alcoholic beverage (cream liquor). In different parts of Africa, the decoction of the bark is traditionally used for the treatment of dysentery, diarrhoea, and various other infectious conditions. The aim of the study was to investigate the anti-biofilm properties of the methanol extract of Marula bark (stem bark of Sclerocarya birrea), with a view towards combating the emergence of antimicrobial resistance often associated with bacterial biofilms.

MATERIALS AND METHODS

The standardized methanol extract was initially tested for its antimicrobial property. The crystal violet assay was used for evaluating anti-biofilm (biofilm formation by Pseudomonas aeuginosa) activity. Further in order to study the mechanism of anti-biofilm activity, the same was evaluated for understanding its role on various quorums sensing mediated phenomenon (swarming motility assay, protease and pyoverdin assay) that are known to be associated with the formation of biofilms and pathogenicity.

RESULTS

The methanol extract showed no inhibition of bacterial growth up to a concentration of 200 µg/ml. Interestingly, the sample produced anti-biofilm activity (around 75% decrease; 100 µg/ml) at sub-lethal concentration. Further it also significantly reduced the QS mediated swarming motility. The release of various virulent factors (protease and pyoverdin) was found to be lowered when pre-treated with the extract.

CONCLUSION

The present study illustrates the anti-biofilm property Sclerocarya birrea. The standardized extract significantly disrupted the quorum sensing mediated production of biofilm formation and also inhibited swarming ability of the cells. The extract displayed a regulatory role on the secretion of protease and pyoverdin, two QS dependent pathogenic factors found in Pseudomonas aeruginosa. This study also validates the ethnobotanical use of Marula.

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.

Conservation strategy for Pelargonium sidoides DC: phenolic profile and pharmacological activity of acclimatized plants derived from tissue culture

ETHNOPHARMACOLOGICAL RELEVANCE

Pelargonium sidoides DC (Geraniaceae), a popular medicinal plant used in folk medicine in the treatment of respiratory-related infections has gained international prominence due to its usage in several herbal formulations. This has led to high demand and the subsequent decimation of wild populations.

AIM OF THE STUDY

Using plant tissue culture techniques, Pelargonium sidoides plants were cloned in vitro, acclimatized under greenhouse conditions and evaluated for their phytochemical content and pharmacological activity.

METHODS

Phenolic content in extracts of in vitro-derived, greenhouse-acclimatized and wild Pelargonium sidoides plants were analyzed using UPLC-MS/MS. The oxygen radical absorbance capacity (ORAC), 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity and minimum inhibitory concentration (MIC) of the extracts against bacterial and fungal strains were evaluated.

RESULTS

Similarities in phenolic profiles were identified confirming the chemical signatures that characterize Pelargonium sidoides plants. Extracts of greenhouse-acclimatized and wild plants exhibited comparable antimicrobial and antioxidant properties.

CONCLUSIONS

Overall, the study highlights the potential of integrating plant tissue culture technologies in conservation strategies of medicinal plants. In particular, the results strongly suggest the feasibility of both large-scale cultivation and plant part substitution as alternative solutions to the current destructive overharvesting practices of wild Pelargonium sidoides populations.

In Vitro Anti-diabetic Activity of Sclerocarya Birrea and Ziziphus Mucronata

Type 2 diabetes mellitus is on the increase worldwide. Current treatments possess undesirable side-effects and therefore investigations into alternative remedies, which may be cost-effective and devoid of such side-effects, are on-going. Aqueous and methanol extracts of the bark of Sclerocarya birrea (A. Rich.) Hochst. subsp. caffra (Sond.) Kokwaro (Anacardiaceae) and Ziziphus mucronata Willd. subsp. mucronata (Rhamnaceae) were subjected to testing in order to assess their in vitro anti-diabetic activity. Total polyphenolic content and antioxidant activity, as well as the effect on α-amylase, α-glucosidase and cytotoxicity, were measured. Furthermore, glucose uptake was evaluated in C2C12 myotubes, 3T3-L1 adipocytes and HepG2 hepatocarcinoma cells, and insulin secretion in RIN-m5F rat pancreatic β-cells. The extracts of both plants inhibited the activities of α-amylase and α-glucosidase in a concentration dependent manner, with results being comparable with the positive control, acarbose. All the extracts contained antioxidant activity, with the methanol extracts of S. birrea displaying the strongest free radical scavenging capacity (IC50 = 2.16 μg/mL). Most of the extracts were not cytotoxic to the cell lines with IC50 values > 100 μg/mL. Extracts of both plants significantly increased glucose uptake in C2C12, 3T3-L1 and HepG2 cells. However, insulin secretion from RIN-m5F cells was not altered. This study provides evidence that the plants possess in vitro anti-diabetic properties.

Antimicrobial, antioxidant, mutagenic and antimutagenic activities of Distephanus angulifolius and Ormocarpum trichocarpum

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of Distephanus angulifolius and Ormocarpum trichocarpum are used for treating stomach-related ailments in traditional medicine.

AIMS OF THE STUDY

The present study evaluated the antibacterial, antioxidant, mutagenic and antimutagenic properties of extracts obtained from the leaves of Distephanus angulifolius and Ormocarpum trichocarpum.

MATERIALS AND METHODS

The microtitre bioassay was used to determine the antibacterial activity against three Gram-positive and three Gram-negative bacteria. Antioxidant activity was determined using the free-radical scavenging and β-carotene-linoleic acid model assays. The safety and possible protective properties of the extracts were investigated using Ames test.

RESULTS

Dichloromethane fractions of both plants displayed a broad-spectrum antibacterial activity with minimum inhibitory concentrations ranging from 0.16 to 0.63 mg/ml. A dose-dependent antioxidant activity was recorded in both plant species. All the evaluated samples showed no mutagenic as well as weak or no antimutagenic properties in the absence of exogenous metabolic activation.

CONCLUSION

The results demonstrated the antibacterial and antioxidant activities of the leaves obtained from the two plant species. Furthermore, the data provides a rationale for the use of the plant species in treating stomach-related ailments in traditional medicine.

Profiling of Phytochemicals in Tissues from Sclerocarya birrea by HPLC-MS and Their Link with Antioxidant Activity

High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was employed to investigate the differences in phytochemicals in roots, bark, and leaf of Sclerocarya birrea (marula) for methanol and water extracts that exhibited the best antioxidant activities. As many as 36 compounds were observed in the extracts of these tissues of which 27 phenolic compounds were tentatively identified. The HPLC-MS/MS results showed flavonoid glycosides were prominent in leaf extracts while the galloylated tannins were largely in bark and root extracts. Four flavonoid glycosides that were reported for the first time in the marula leaf have been identified. The HPLC-MS/MS studies also illustrated different degrees (highest degree = 3) of oligomerisation and galloylation of tannins in the bark and root extracts.

Phenolic composition, antioxidant and anti-acetylcholinesterase activities of the Tunisian Scabiosa arenaria

CONTEXT

There is a need for the discovery of novel natural antioxidants and acetylcholinesterase inhibitors (AChEIs) that are safe and effective at a global level. This is the first study on antioxidant and anti-acethylcholinesterase activity of Scabiosa arenaria Forssk (Dipsacaceae).

OBJECTIVE

The antioxidant potential and anti-acetylcholinesterase (AChE) activity of S. arenaria were investigated.

MATERIAL AND METHODS

The crude, ethyl acetate (EtOAc), butanol (n-BuOH) and water extracts prepared from flowers, fruits and stems and leaves of S. arenaria were tested to determine their total polyphenol content (TPC), total flavonoid content (TFC), total condensed tannin content (CTC) and their antioxidant activity by using 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), reducing power and β-carotene bleaching inhibition activity. Anti-AChE activity was also determined.

RESULTS

EtOAc and n-BuOH fractions of fruits had both the highest (TPC) (269.09 mg gallic acid equivalents/g dry weight). The crude extract of stems and leaves had the highest TFC (10.9 mg quercetin equivalent/g dry weight). The n-BuOH fraction of stems and leaves had the highest CTC (489.75 mg catechin equivalents/g dry weight). The EtOAc fraction of flowers exhibit a higher activity in each antioxidant system with a special attention for DPPH assay (IC50 = 0.017 mg/mL) and reducing power (EC50 = 0.02 mg/mL). The EtOAc and n-BuOH fractions of stems and leaves showed strong inhibition of AChE (IC50 = 0.016 and 0.029 mg/mL, respectively).

DISCUSSION AND CONCLUSIONS

These results suggest the potential of S. arenaria as a possible source of novel compounds and as an alternative antioxidant and AChEIs.

Commercially Important Medicinal Plants of South Africa: A Review

There is a growing interest in natural plant-based remedies as a source for commercial products. Around 80% of the South African population use traditional medicines to meet their primary health care needs; however, only a few South African medicinal plants have been exploited to their full potential in terms of commercialization. The opportunity for bioprospecting of plant compounds for novel pharmaceuticals remains largely untapped. Certain renowned medicinal plants of international acclaim including buchu and rooibos are currently contributing to local enterprise; however, other exciting opportunities exist for commonly used plants which have not yet reached the international arena. This paper focuses on the key research and development contributions of 10 commercially important medicinal plants of South Africa. Traditional uses, scientific validation, commercialisation developments, as well as both potential opportunities and setbacks are discussed.

Pharmacological properties and protein binding capacity of phenolic extracts of some Venda medicinal plants used against cough and fever

ETHNOPHARMACOLOGY RELEVANCE

Several ailments are caused by infectious bacteria and in other diseases; they act as co-infection which complicate human life by causing health hazards. In Venda (South Africa), many plants are used in traditional medicine to treat cough and fever.

AIM OF THE STUDY

This study was aimed at evaluating the antibacterial and antifungal properties, cyclooxygenases (COX), acetylcholinesterase (AChE) enzyme inhibitory effects and the phenolic composition as well as mutagenic properties of six medicinal plants used by the Venda people of Limpopo Province of South Africa against cough and fever.

MATERIALS AND METHODS

The petroleum ether (PE), dichloromethane (DCM), 80% ethanol (EtOH) and water extracts of six plants were tested against four infectious bacteria (Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus) and a fungus Candida albicans. The same extracts were evaluated for their ability to inhibit COX-1 and -2 enzymes. Methanolic and water extracts of the same plant were tested for acetylcholinesterase inhibitory effects. Total phenolics, flavonoids, gallotannins and condensed tannins were determined. The ability of the extracts to bind and precipitate proteins was also investigated. The extracts were investigated for genotoxicity with and without S9 (metabolic activation) against three Salmonella typhimurium tester strains TA98, TA100 and TA102.

RESULTS

The organic extracts of Rhus lancea leaves exhibited the best antibacterial activity with minimum inhibitory concentration (MIC) values ranging from 0.0061 to 0.049mg/ml. The best antifungal activity was observed from a DCM extract of Syzygium cordatum leaves with a MIC value of 0.195mg/ml. The methanolic and water extracts of the same plant exhibited high inhibitory effects towards AChE with IC(50) values of 0.22 and 0.26mg/ml, respectively. The highest levels of flavonoids and gallotannins were detected in Spirostachys africana bark; 11.57 and 48.88μg/g, respectively. The highest percentages (1.2%) of condensed tannins were detected in Uvaria caffra leaves. The high levels of phenolic compounds may have been responsible for high antimicrobial activities for extracts of S. africana bark and U. caffra leaves. S. cordatum leaves represented the highest affinity for protein binding with 93%. All the extracts were non-mutagenic towards the three tested strains with and without S9 metabolic activation.

CONCLUSION

The result obtained in this study goes a long way in validating the ethnobotanical usage of these medicinal plants in the treatment of cough and fever by the Venda people. However, more evidence obtainable from other assays not performed here are urgently required to confirm these results.