Anogeissus leiocarpus (DC.) Guill. & Perr. (Combretaceae): A review of the traditional uses, phytochemistry and pharmacology of African birch.

Anogeissus leiocarpus (DC.) Guill. & Perr. belongs to the family Combretaceae and is used both by African traditional medical practitioners and livestock rearers to treat diseases such as African trypanosomiasis, animal diarrhoea, asthma, cancer, cough, diabetes, dysentery, erectile dysfunction, fever, giardiasis, helminthiases, meningitis, menstrual disorders, monkeypox, oral infections, poliomyelitis, sickle cell anaemia, snake bites, toothache, urinary schistosomiasis, and yellow fever. Some of these activities have been associated with the presence of polyphenols in the plant which include ellagic acid derivatives, flavonoids, stilbenes, tannins, and triterpenes. Several bioactive molecules have been identified from A. leiocarpus. These include the main active constituents, ellagitannins, ellagic acid derivates, flavonoids and triterpenes. Pharmacological studies have confirmed its antibacterial, antifungal, antihyperglycemic, antihypertensive, antimalarial, antioxidative, antiparasitic, antitumour and anti-ulcer effects. The stem bark has been investigated mainly for biological activities and phytochemistry, and it is the most mentioned plant part highlighted by the traditional users in ethnomedicinal surveys. In vitro and in vivo models, which revealed a wide range of pharmacological actions against parasites causing helminthiasis, leishmaniasis, malaria and trypanosomiasis, have been used to study compounds from A. leiocarpus. Because of its uses in African traditional medicine and veterinary practices, A. leiocarpus has received considerable attention from researchers. The current review provides a comprehensive overview and critical appraisal of scientific reports on A. leiocarpus, covering its traditional uses, pharmacological activities and phytochemistry.

Ceibinin, a new positional isomer of mangiferin from the inflorescence of Ceiba pentandra (Bombacaceae), elicits similar antioxidant effect but no anti-inflammatory potential compared to mangiferin.

Ceiba pentandra (L.) Gaertn. (Bombacaceae) is popular for the quality of its wood. However, its leaf, stem bark and root bark have been popular in ethnomedicine and, apart from the inflorescence, have been subject of extensive phytochemical investigations. In this study, two compounds were isolated from the crude methanol extract of the inflorescence. Through data from UV, NMR, MS, electrochemical studies, differential scanning calorimetry, and thermogravimetric analysis, the structures were elucidated as 3-C-ß-d-glucopyranosyl-1,3,6,7-tetrahydroxyxanthone (1) and 2-C-ß-d-glucopyranosyl-1,3,6,7-tetrahydroxyxanthone (mangiferin, 2). They were assessed for antioxidant efficacy (DCFDA assay) and for anti-inflammatory efficacy using the lipopolysaccharide (LPS)-induced inflammation model in the RAW 264.7 macrophages (nitrite levels quantified, using Griess Assay, as surrogate for nitric oxide (NO)). Compound 1 (named ceibinin) was established as a novel positional isomer of mangiferin (2). While both 1 and 2 were antioxidant against basal and hydrogen peroxide (100 µM)-induced oxidative stress (6.25 µg/ml abrogated peroxide-induced oxidative stress), ceibinin (1) demonstrated no anti-inflammatory potential, unlike mangiferin (2) which, as previously reported, showed anti-inflammatory effect. Our work reports a positional isomer of mangiferin for the first time in C. pentandra and demonstrates how such isomerism could underlie differences in biological activities and thus the potential for development into therapeutics.

Shikonin and Juglone Inhibit Mycobacterium tuberculosis Low-Molecular-Weight Protein Tyrosine Phosphatase a (Mt-PTPa).

Low-molecular-weight protein tyrosine phosphatases (LMW-PTPs) are involved in promoting the intracellular survival of Mycobacterium tuberculosis (Mtb), the causative organism of tuberculosis. These PTPs directly alter host signalling pathways to evade the hostile environment of macrophages and avoid host clearance. Among these, protein tyrosine phosphatase A (Mt-PTPa) is implicated in phagosome acidification failure, thereby inhibiting phagosome maturation to promote Mycobacterium tuberculosis (Mtb) survival. In this study, we explored Mt-PTPa as a potential drug target for treating Mtb. We started by screening a library of 502 pure natural compounds against the activities of Mt-PTPa in vitro, with a threshold of 50% inhibition of activity via a <500 µM concentration of the candidate drugs. The initial screen identified epigallocatechin, myricetin, rosmarinic acid, and shikonin as hits. Among these, the naphthoquinone, shikonin (5, 8-dihydroxy-2-[(1R)-1-hydroxy-4-methyl-3-pentenyl]-1,4-naphthoquinone), showed the strongest inhibition (IC50 33 µM). Further tests showed that juglone (5-hydroxy-1,4-naphthalenedione), another naphthoquinone, displayed similar potent inhibition of Mt-PTPa to shikonin. Kinetic analysis of the inhibition patterns suggests a non-competitive inhibition mechanism for both compounds, with inhibitor constants (Ki) of 8.5 µM and 12.5 µM for shikonin and juglone, respectively. Our findings are consistent with earlier studies suggesting that Mt-PTPa is susceptible to specific allosteric modulation via a non-competitive or mixed inhibition mechanism.

Cytotoxic triterpenoid saponins from the root of Olax subscorpioidea Oliv. (Olacaceae).

Bioactivity-guided phytochemical fractionation of the methanol extract of Olax subscorpioidea root has led to the isolation of six triterpenes. Three of these compounds are previously undescribed triterpenoid saponins: oleanolic acid 3-O-[α-L-rhamnopyranosyl-(1→3)-ß-D-glucopyranosyl-(1 â†’ 2)-6-O-methyl-ß-D-glucuronopyranoside]-28-O-ß-D-glucopyranosyl ester (2), oleanolic acid 3-O-[ß-D-glucopyranosyl-(1 â†’ 4)-ß-D-glucopyranosyl-(1 â†’ 3)-ß-D-glucopyranoside] (3), and oleanolic acid 3-O-[ß-D-glucopyranosyl-(1 â†’ 4)-6-O-methyl-ß-D-glucuronopyranoside] ester (5). Other reported known compounds include two triterpene glycosides: oleanolic acid 3-O-[ß-D-glucopyranosyl-(1 â†’ 4)-6-O-methyl-ß-D-glucuronopyranoside]-28-O-ß-D-glucopyranosyl ester (1) and oleanolic acid 3-O-[ß-D-glucopyranosyl-(1 â†’ 4)-ß-D-glucuronopyranoside] (4); and a triterpene acid, oleanolic acid (6). The structures of these compounds were elucidated by spectroscopic means. The isolated compounds were tested against human cervical cancer (HeLa), colorectal cancer (Caco-2) and breast cancer (MCF-7) cell lines using the in vitro 3-[4,5-dimethylthiazole-2-yl] 3,5-diphenyltetrazolium bromide (MTT) assay, with vincristine as positive control. The cytotoxicity assay showed that compounds 3 and 5 exhibited significant inhibitory effects on the HeLa cell line, with IC50 values of 7.42 ± 0.34 µM and 10.27 ± 1.26 µM; and moderate effects on MCF-7 (IC50 values, 36.67 ± 1.23 µM and 43.83 ± 0.65 µM) and Caco-2 (IC50 values, 35.83 ± 0.55 µM and 39.03 ± 4.38 µM, respectively) cell lines. They were also more selectively cytotoxic than vincristine against the cancer cell lines, when compared with cytotoxicity against the normal lung cell line MRC5.

The Use of Micro-Ribbons and Micro-Fibres in the Formulation of 3D Printed Fast Dissolving Oral Films.

Three-dimensional printing (3DP) allows production of novel fast dissolving oral films (FDFs). However, mechanical properties of the films may not be desirable when certain excipients are used. This work investigated whether adding chitosan micro-ribbons or cellulose microfibres will achieve desired FDFs by fused deposition modelling 3DP. Filaments containing polyvinyl alcohol (PVA) and paracetamol as model drug were manufactured at 170 °C. At 130 °C, filaments containing polyvinylpyrrolidone (PVP) and paracetamol were also created. FDFs were printed with plain or mesh patterns at temperatures of 200 °C (PVA) or 180 °C (PVP). Both chitosan micro-ribbons and cellulose micro-fibres improved filament mechanical properties at 1% w/w concentration in terms of flexibility and stiffness. The filaments were not suitable for printing at higher concentrations of chitosan micro-ribbons and cellulose micro-fibres. Furthermore, mesh FDFs containing only 1% chitosan micro-ribbons disintegrated in distilled water within 40.33 ± 4.64 s, while mesh FDFs containing only 7% croscarmellose disintegrated in 55.33 ± 2.86 s, and croscarmellose containing films showed signs of excipient scorching for PVA polymer. Cellulose micro-fibres delayed disintegration of PVA mesh films to 108.66 ± 3.68 s at 1% w/w. In conclusion, only chitosan micro-ribbons created a network of hydrophilic channels within the films, which allowed faster disintegration time at considerably lower concentrations.

Cola rostrata K. Schum. constituents induce cytotoxicity through reactive oxygen species generation and mitochondrial membrane depolarisation.

Aim: While the traditional use of Cola rostrata in treating illnesses and diseases has not been reported, the presence of cytotoxic principles has been reported in phylogenetically and biogeographically related species within the Cola genus. This study, therefore, evaluated the cytotoxic potential of extracts of the plant, and the associated cellular and molecular mechanisms. Methods: Activity-based fractionation of the extracts was carried out and cytotoxicity was assessed in the human cervical cancer cell line, HeLa, and the transformed human lung cell line, MRC5-SV2, using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay complemented with brightfield imaging. The 2',7'-dichlorofluorescein diacetate (DCFDA) assay was used to assess induction of cellular reactive oxygen species (ROS), while flow cytometry of 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethyl-imidacarbocyanine iodide (JC-1)-stained cells assessed the loss of mitochondrial membrane potential (∆ΨM). Gas chromatography-mass spectrometry (GC-MS) analysis was carried out on an active fraction. Results: Extracts of the fruit epicarp and leaf were cytotoxic against the cell lines. Half-maximal inhibitory concentration (IC50) values for the 48 h cytotoxicity of the ethanol extract of the epicarp against HeLa and MRC5-SV2 cells were 48.0 µg/mL ± 12.1 µg/mL and 40.4 µg/mL ± 7.2 µg/mL, respectively, while fractions from second-level partitioning of the hexane fraction of the leaf extract elicited cytotoxicity with IC50 values ranging from 12.8 µg/mL ± 1.0 µg/mL to 39.6 µg/mL ± 7.2 µg/mL in both cell lines, following 48 h treatment. GC-MS revealed the presence of seventeen compounds in a hexane fraction of the leaf extract, including even- and odd-chain fatty acids, the most abundant of which were n-hexadecanoic acid, decanoic acid 10-(2-hexylcyclopropyl); and octadecanoic acid. The mechanisms of cytotoxicity of most active fractions involved generation of ROS and mitochondrial membrane depolarisation. Conclusions: The findings show that C. rostrata is rich in cytotoxic phytochemicals which could be isolated for developing new anti-cancer agents.

Synthesis, substitution kinetics, DNA/BSA binding and cytotoxicity of tridentate N

The pincer complexes, [Pd(L1)Cl]BF4 (PdL1), [Pd(L2)Cl]BF4 (PdL2), [Pd(L3)Cl]BF4 (PdL3), [Pd(L4)Cl]BF4 (PdL4) were prepared by reacting the corresponding ligands, 2,6-bis[(1H-pyrazol-1-yl)methyl]pyridine (L1), bis[2-(1H-pyrazol-1-yl)ethyl]amine (L2), bis[2-(1H-pyrazol-1-yl)ethyl]ether (L3), and bis[2-(1H-prazol-1-yl)ethyl]sulphide (L4) with [PdCl2(NCMe)]2 in the presence NaBF4. The solid-state structures of complexes PdL1-PdL4 confirmed a tridentate coordination mode, with one chloro ligand completing the coordination sphere to afford square-planar complexes. Chemical behaviour of the complexes in solution confirms their stability in both aqueous and DMSO stock media. The electrochemical properties of the compounds showed irreversible two-electron reduction process. Kinetic reactivity of Pd complexes with the biological nucleophiles viz, thiourea (Tu), L-methionine (L-Met) and guanosine 5'-diphosphate disodium salt (5'-GMP) followed the order: PdL2 < PdL3 < PdL4, and PdL2 < PdL1. The kinetic reactivity is subject to the electronic effects of the spectator ligand(s), and the trend was supported by the DFT computed results. The palladium complexes PdL1-PdL4 bind to calf thymus (CT-DNA) via intercalation mode. In addition, the bovine serum albumin (BSA) showed good binding affinity to the complexes. The mode of quenching mechanism of the intrinsic fluorescence of CT-DNA and BSA by the complexes was found to be static. The order of interactions of the complexes with DNA and BSA was in tandem with the rate of substitution kinetics. The complexes, however, displayed relatively low cytotoxicity (IC50 > 100 µM) when tested against the human cervical adenocarcinoma (HeLa) cell line and the transformed human lung fibroblast cell line (MRC-5 SV2).

West African medicinal plants and their constituent compounds as treatments for viral infections, including SARS-CoV-2/COVID-19.

OBJECTIVES: The recent emergence of the COVID-19 pandemic (caused by SARS-CoV-2) and the experience of its unprecedented alarming toll on humanity have shone a fresh spotlight on the weakness of global preparedness for pandemics, significant health inequalities, and the fragility of healthcare systems in certain regions of the world. It is imperative to identify effective drug treatments for COVID-19. Therefore, the objective of this review is to present a unique and contextualised collection of antiviral natural plants or remedies from the West African sub-region as existing or potential treatments for viral infections, including COVID-19, with emphasis on their mechanisms of action. EVIDENCE ACQUISITION: Evidence was synthesised from the literature using appropriate keywords as search terms within scientific databases such as Scopus, PubMed, Web of Science and Google Scholar. RESULTS: While some vaccines and small-molecule drugs are now available to combat COVID-19, access to these therapeutic entities in many countries is still quite limited. In addition, significant aspects of the symptomatology, pathophysiology and long-term prognosis of the infection yet remain unknown. The existing therapeutic armamentarium, therefore, requires significant expansion. There is evidence that natural products with antiviral effects have been used in successfully managing COVID-19 symptoms and could be developed as anti-COVID-19 agents which act through host- and virus-based molecular targets. CONCLUSION: Natural products could be successfully exploited for treating viral infections/diseases, including COVID-19. Strengthening natural products research capacity in developing countries is, therefore, a key strategy for reducing health inequalities, improving global health, and enhancing preparedness for future pandemics.

Peristrophe bicalyculata (Retz) Nees contains principles that are cytotoxic to cancer cells and induce caspase-mediated, intrinsic apoptotic death through oxidative stress, mitochondrial depolarisation and DNA damage.

The plant Peristrophe bicalyculata (Retz) Nees is used for the treatment of cancer. While its leaf extracts have been shown to inhibit the growth of some cancer cells, there is little information supporting the constituents' anti-tumour potential. This study, therefore, investigated the effects of the plant's leaf extracts on cancer cells and the associated cellular/molecular mechanisms. Extracts were prepared using hexane (PBH), chloroform (PBC), ethyl acetate (PBE) and methanol (PBM) and constituents were identified by Liquid Chromatography-Mass Spectrometry (LC-MS). Their cytotoxic effects on human cervical (HeLa) and lung cancer (MRC5-SV2) cells were assessed using the MTT and LDH release assays. Reactive oxygen species (ROS) production was assessed using 2',7'-dichlorofluorescein diacetate (DCFDA) and mitochondrial membrane potential by staining with JC-1 (5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolyl-carbocyanine iodide). Caspase activation was determined using a Caspase-Glo-3/7 assay, and DNA damage by the Comet assay. Changes to mRNA expression were assessed using Quantitative Real-Time PCR. PBC, PBE and PBM reduced cell viability and induced LDH release, with IC50 values (48 h, MTT, in µg/ml), respectively, of 6.21 ± 0.70, 23.39 ± 3.92, and 22.43 ± 3.58 (HeLa); and 1.98 ± 0.33, 8.57 ± 1.91 and 28.24 ± 5.57 (MRC5-SV2). PBC induced ROS, while PBC, PBE and PBM impaired mitochondrial membrane potential and induced caspase 3/7 activation. PBC and PBE induced DNA damage, and PBE induced caspase-3 mRNA expression. Constituents of the extracts included derivatives of gallic acid, dipeptides, diterpenoids and flavones. We conclude that P. bicalyculata contains cytotoxic principles that could be potential leads for developing novel anti-cancer agents.

Potent Nrf2-inducing, antioxidant, and anti-inflammatory effects and identification of constituents validate the anti-cancer use of Uvaria chamae and Olax subscorpioidea.

BACKGROUND: Uvaria chamae (UC) and Olax subscorpioidea (OS) roots are included in traditional anti-cancer remedies and some studies have identified their chemopreventive/chemotherapeutic potential. This study aimed to identify some cellular/molecular mechanisms underlying such potential and the associated chemical constituents. METHODS: Effect on the viability of cancer cells was assessed using the Alamar Blue assay; ability to modulate oxidative stress was assessed using the 2',7'-dichlorofluorescein diacetate (DCFDA) assay; potential to modulate Nuclear factor erythroid 2-related factor like-2 (Nrf2) activity was assessed in the AREc32 luciferase reporter cell line; and anti-inflammatory effect was assessed using lipopolysaccharide-induced nitric oxide release model in the RAW264.7 cells (Griess Assay). Chemical constituents were identified through liquid chromatography-mass spectrometry (LC-MS). RESULTS: Extracts up to 100 µg/ml were non-toxic or mildly toxic to HeLa, AREc32, PC3 and A549 cells (IC50 > 200 µg/ml). Each extract reduced basal and peroxide-induced levels of reactive oxygen species (ROS) in HeLa cells. OS and UC activated Nrf2, with UC producing nearly four-fold induction. Both extracts demonstrated anti-inflammatory effects. Chamanetin, isochamanetin, isouvaretin, uvaricin I and other compounds were found in U. chamae root extract. CONCLUSION: As Nrf-2 induction, antioxidant and anti-inflammatory activities are closely linked with chemoprevention and chemotherapy of cancers, the roles of these plants in traditional anti-cancer remedies are further highlighted, as is their potential as sources of drug leads.

Anthelmintic activity and non-cytotoxicity of phaeophorbide-a isolated from the leaf of Spondias mombin L.

ETHNOPHARMACOLOGICAL RELEVANCE: Helminthosis (worm infection) is a disease of grazing livestock, with significant economic implications. Increasing resistance to existing synthetic anthelmintics used to control helminthosis and the unwanted presence of residues of the anthelmintics reported in meat and dairy products present a serious global health challenge. These challenges have necessitated the development of novel anthelmintics that could combat drug resistance and exhibit better safety profiles. Spondias mombin L. (Anacardiaceae) is a plant that has been used traditionally as a worm expeller. AIM OF STUDY: The aim of the work reported herein was to isolate and characterise anthelmintic compound(s) from S. mombin leaf, establishing their bioactivity and safety profile. MATERIALS AND METHODS: Adult Haemonchus placei motility assay was used to assess anthelmintic bioactivity. Bioassay-guided chromatographic fractionation of acetone extract of S. mombin leaf was carried out on a silica gel stationary phase. The structure of the compound was elucidated using spectroscopy (1H and 13C NMR) and Liquid Chromatography-Mass Spectrometry (LC-ESI-MS). Screening to exclude potential cytotoxicity against mammalian cells (H460, Caco-2, MC3T3-E1) was done using alamar blue (AB) and CellTitreGlo (CTG) viability reagents. RESULTS: The acetone extract yielded an active fraction 8 (Ethyl acetate: methanol 90:10; anthelmintic LC50: 3.97 mg/mL), which yielded an active sub-fraction (Ethyl acetate: Methanol 95:5; anthelmintic LC50: 53.8 µg/mL), from which active compound 1 was isolated and identified as phaeophorbide-a (LC50: 23.0 µg/mL or 38.8 µM). The compound was not toxic below 200 µM but weakly cytotoxic at 200 µM. CONCLUSIONS: Phaeophorbide-a (1) isolated from S. mombin leaf extract and reported in the plant for the first time in this species demonstrated anthelmintic activity. No significant toxicity to mammalian cells was observed. It therefore represents a novel anthelmintic pharmacophore as a potential lead for the development of novel anthelmintics.

Physiological and Pathological Factors Affecting Drug Delivery to the Brain by Nanoparticles.

The prevalence of neurological/neurodegenerative diseases, such as Alzheimer's disease is known to be increasing due to an aging population and is anticipated to further grow in the decades ahead. The treatment of brain diseases is challenging partly due to the inaccessibility of therapeutic agents to the brain. An increasingly important observation is that the physiology of the brain alters during many brain diseases, and aging adds even more to the complexity of the disease. There is a notion that the permeability of the blood-brain barrier (BBB) increases with aging or disease, however, the body has a defense mechanism that still retains the separation of the brain from harmful chemicals in the blood. This makes drug delivery to the diseased brain, even more challenging and complex task. Here, the physiological changes to the diseased brain and aged brain are covered in the context of drug delivery to the brain using nanoparticles. Also, recent and novel approaches are discussed for the delivery of therapeutic agents to the diseased brain using nanoparticle based or magnetic resonance imaging guided systems. Furthermore, the complement activation, toxicity, and immunogenicity of brain targeting nanoparticles as well as novel in vitro BBB models are discussed.

The Effects of Solid and Liquid Lipids on the Physicochemical Properties of Nanostructured Lipid Carriers.

The aim of this work was to identify from a review of current literature the effects of lipids used in the development of Nanostructured Lipid Carriers (NLCs) on the physicochemical properties of the resulting formulation. The size of the solid lipid, affected by the molecular weight and the complexity of the structure, tends to affect the particle size of the final formulation proportionally; the higher the molecular weight and the more complex the molecular structure, the bigger the particle size of the NLCs. However, there is no straight correlation between the size and the structure of the liquid lipid and the particle size. Moreover, there seems to be a correlation of the solid to liquid lipid ratio which affects the particle size; there has been a trend of increasing particle size when more solid lipid was used. Regarding the entrapment efficiency, it is highly affected by the drug and its interaction with the lipids, as its solubility in the lipids needs to be high so the drug can stay entrapped within the lipid core. There was no direct correlation between the type of lipid used or the ratio and the zeta potential, which affects the stability of the NLCs.

Kola nut from Cola nitida vent. Schott administered to pregnant rats induces histological alterations in pups' cerebellum.

Kola nut (from Cola nitida) is popular in Nigeria and West Africa and is commonly consumed by pregnant women during the first trimester to alleviate morning sickness and dizziness. There is, however, a dearth of information on its effects on the developing brain. This study, therefore, investigated the potential effects of kola nut on the structure of the developing neonatal and juvenile cerebellum in the rat. Pregnant Wistar rats were administered water (as control) or crude (aqueous) kola nut extract at 400, 600, and 800 mg/kg body weight orally, from pregnancy to day 21 after birth. On postnatal days 1, 7, 14, 21 and 28, the pups were weighed, anaesthetised, sacrificed and perfused with neutral buffered formalin. Their brains were dissected out, weighed and the cerebellum preserved in 10% buffered formalin. Paraffin sections of the cerebellum were stained with haematoxylin and eosin for cerebellar cytoarchitecture, cresyl violet stain for Purkinje cell count, Glial Fibrillary Acidic Protein (GFAP) immunohistochemistry (IHC) for estimation of gliosis, and B-cell lymphoma 2 (Bcl-2) IHC for apoptosis induction. The kola nut-treated rats exhibited initial reduction in body and brain weights, persistent external granular layer, increased molecular layer thickness, and loss of Bergmann glia. Their Purkinje cells showed reduction in density, loss of dendrites and multiple layering, and their white matter showed neurodegeneration (spongiosis) and GFAP and Bcl-2 over-expression, with evidence of reactive astrogliosis. This study, therefore, demonstrates that kola nut, administered repeatedly at certain doses to pregnant dams, could disrupt normal postnatal cerebellar development in their pups. The findings suggest potential deleterious effects of excessive kola nut consumption on human brain and thus warrant further studies to understand the wider implications for human brain development.

Bioactivity and cytotoxicity profiling of vincosamide and strictosamide, anthelmintic epimers from Sarcocephalus latifolius (Smith) Bruce leaf.

ETHNOPHARMACOLOGICAL RELEVANCE: The leaf of Sarcocephalus latifolius is known to be used traditionally by the Fulanis in Nigeria to deworm animals. As helminthosis remains a major constraint to profitable livestock production worldwide, a precarious situation aggravated by the advent of resistant parasites, the discovery of new anthelmintics is a priority, necessitating exploration of medicinal plants for their anthelmintic principles. AIM OF THE STUDY: To identify and characterise compounds with anthelmintic activity from the leaf of Sarcocephalus latifolius. MATERIALS AND METHODS: Powdered S. latifolius leaves were extracted by successive maceration with n-hexane, chloroform and acetone. The dried extracts were evaluated for anthelmintic activity against Haemonchus placei adult worms, and the most active extract was subjected to bioassay-guided chromatographic separations. The isolated compounds were evaluated for cytotoxicity against the mammalian HeLa and MC3T3-E1 cell lines, using alamar blue and CellTitreGloTM to quantify cell viability. LC50 values were computed from the in vitro anthelmintic activity data by fitting to a non-linear regression equation (variable slope). Isolated compounds were characterized using spectroscopic and mass spectrometric analyses. RESULTS: Anthelmintic activity LC50 values for n-hexane, chloroform and acetone extracts were 47.85, 35.76 and 5.72 (mg/mL), respectively. Chromatographic separation of acetone extract afforded two bioactive epimers, identified as vincosamide (LC50 14.7 mg/mL) and strictosamide (LC50 12.8 mg/mL). Cytotoxicity evaluation showed that, below 200 µg/mL (400 µM), neither compound was toxic to the HeLa or MC3T3-E1 cells. CONCLUSION: Vincosamide and strictosamide could serve as novel scaffolds for the development of anthelmintic derivatives with improved potency and helminth selectivity.

The Inclusion of a Matrix Metalloproteinase-9 Responsive Sequence in Self-assembled Peptide-based Brain-Targeting Nanoparticles Improves the Efficiency of Nanoparticles Crossing the Blood-Brain Barrier at Elevated MMP-9 Levels.

This study investigated whether the inclusion of a matrix metalloproteinase-9 (MMP-9) responsive sequence in self-assembled peptide-based brain-targeting nanoparticles (NPs) would enhance the blood-brain barrier (BBB) penetration when MMP-9 levels are elevated both in the brain and blood circulation. Brain-targeting peptides were conjugated at the N-terminus to MMP-9-responsive peptides, and these were conjugated at the N-terminus to lipid moiety (cholesteryl chloroformate or palmitic acid). Two constructs did not have MMP-9-responsive peptides. NPs were characterised for size, charge, critical micelle concentration, toxicity, blood compatibility, neural cell uptake, release profiles, and in vitro BBB permeability simulating normal or elevated MMP-9 levels. The inclusion of MMP-9-sensitive sequences did not improve the release of a model drug in the presence of active MMP-9 from NPs compared to distilled water. 19F NMR studies suggested the burial of MMP-9-sensitive sequences inside the NPs making them inaccessible to MMP-9. Only cholesterol-GGGCKAPETALC (responsive to MMP-9) NPs showed <5% haemolysis, <1 pg/mL release of IL-1ß at 500 µg/mL from THP1 cells, with 70.75 ± 5.78% of NPs crossing the BBB at 24 h in presence of active MMP-9. In conclusion, brain-targeting NPs showed higher transport across the BBB model when MMP-9 levels were elevated and the brain-targeting ligand was responsive to MMP-9.

Isolation and Characterisation of Two Quercetin Glucosides with Potent Anti-Reactive Oxygen Species (ROS) Activity and an Olean-12-en Triterpene Glucoside from the Fruit of Abelmoschus esculentus (L.) Moench.

Abelmoschus esculentus (Okra) is used in the traditional treatment of cancer, hyperlipidaemia and hyperglycaemia. We, therefore, investigated its composition and potential cytotoxic or antioxidant properties that might underlie its phytotherapeutic applications. Its methanolic fruit extract yielded compounds 1, 2 and 3, identified through NMR, UV and MS analyses as olean-12-en-3-O-ß-d-glucopyranoside, isoquercitrin (quercetin glucoside) and 5,7,3',4'-tetrahydroxy-flavonol-3-O-[ß-d-glucopyranosyl-(1→6)]-ß-d-glucopyranoside (quercetin diglucoside), respectively. Following 48 h exposure, oleanene glucoside was mildly toxic to the HeLa and the MRC5-SV2 cancer cells, isoquercitrin was not toxic except at 100 µg/ml in HeLa, and quercetin diglucoside elicited no toxicity. In a 2',7'-dichlorofluorescein diacetate (DCFDA) assay of intracellular levels of reactive oxygen species (ROS), hydrogen peroxide increased ROS levels, an effect not affected by oleanene glucoside but protected against by isoquercitrin and quercetin diglucoside, with IC50 values, respectively, of 2.7±0.5 µg/ml and 1.9±0.2 µg/ml (3 h post-treatment) and 2.0±0.8 µg/ml and 1.5±0.4 µg/ml (24 h post-treatment.) This is the first report of this oleanene skeleton triterpenoid in the plant. The work provides some insight into why the plant is included in remedies for cancers, cardiovascular complications and diabetes, and reveals it as a potential source of novel therapeutics.

Pentagalloylglucose, isolated from the leaf extract of Anacardium occidentale L., could elicit rapid and selective cytotoxicity in cancer cells.

BACKGROUND: The leaf of Anacardium occidentale L. has been a component of many herbal recipes in South-Western Nigeria. The work reported herein, therefore, explored the phytochemical composition of this plant and the potential anti-cancer activity of an isolated chemical constituent. METHODS: Phytochemical methods (including chromatographic analysis) combined with spectroscopic and spectrometric analyses (IR, HRMS and NMR (1D and 2D)) were used to identify chemical constituents. Cytotoxic effects were determined using the MTT viability assay and bright-field imaging. Induction of oxidative stress was determined using the fluorescence-based 2',7'-dichlorofluorescein diacetate (DCFDA) assay. RESULTS: For the first time in the plant, Compound 1 was isolated from the leaf extract and identified as pentagalloylglucose. Compound 1 was significantly cytotoxic against the cancer cell lines HeLa (human cervical adenocarcinoma cell line) and MRC5-SV2 (human foetal lung cancer cell line), with IC50 of 71.45 and 52.24 µg/ml, respectively. The selectivity index (SI) for Compound 1 was 1.61 (IC50 against the normal human foetal lung fibroblast cell line MRC-5 was 84.33µg/ml), demonstrating better cancer cell-selectivity compared to doxorubicin with a SI of 1.28. The cytotoxic activity of Compound 1 in HeLa cells was also rapid, as shown by its concentration- and time-dependent 3 h and 6 h cytotoxicity profiles, an effect not observed with doxorubicin. Generation of reactive oxygen species at high concentrations of pentagalloylglucose to induce oxidative stress in cancer cells was identified as a mechanistic event that led to or resulted from its cytotoxicity. CONCLUSIONS: We suggest that pentagalloylglucose is selectively cytotoxic to cancer cells, and at high concentrations could exhibit pro-oxidant effects in those cells, as opposed to its general anti-oxidant effects in cells. Also, the presence of Compound 1 (pentagalloylglucose) in the plant and its cancer cell-selective cytotoxicity provide some rationale for the ethno-medicinal use of the plant's leaf extract for treating diseases associated with excessive cell proliferation. Further studies are required to dissect the molecular mechanisms and players differentially regulating the biphasic anti-oxidant and pro-oxidant effects of pentagalloylglucose in normal and cancer cells.

Development of Brain Targeting Peptide Based MMP-9 Inhibiting Nanoparticles for the Treatment of Brain Diseases with Elevated MMP-9 Activity.

Latent and active levels of cerebral matrix metalloproteinase 9 (MMP-9) are elevated in neurological diseases and brain injuries, contributing to neurological damage and poor clinical outcomes. This study aimed developing peptide-based nanoparticles with ability to cross the blood-brain-barrier (BBB) and inhibit MMP-9. Three amphiphilic peptides were synthesised containing brain-targeting ligands (HAIYPRH or CKAPETALC) conjugated with MMP-9 inhibiting peptide (CTTHWGFTLC) linked by glycine (spacer) at the N-terminus, and the peptide sequences were conjugated at the N- terminus to cholesterol. 19F NMR assay was developed to measure MMP-9 inhibition. Cell toxicity was evaluated by the LDH assay, and dialysis studies were conducted with/without fetal bovine serum. An in vitro model was employed to evaluate the ability of nanoparticles crossing the BBB. The amphiphilic peptide (Cholesterol-GGGCTTHWGFTLCHAIYPRH) formed nanoparticles (average size of 202.8 nm) with ability to cross the BBB model. MMP-9 inhibiting nanoparticles were non-toxic to cells, and reduced MMP-9 activity from kobs of 4.5 × 10-6s-1 to complete inhibition. Dialysis studies showed that nanoparticles did not disassemble by extreme dilution (40 folds), but gradually hydrolysed by serum enzymes. In conclusion, the MMP-9 inhibiting nanoparticles reduced the activity of MMP-9, with acceptable serum stability, minimal cell toxicity and ability to cross the in vitro BBB model.