Acalypha wilkesiana extracts induce apoptosis by causing single strand and double strand DNA breaks

Ethnopharmacological relevance: The seeds of Acalypha wilkesiana have been used empirically by traditional healers in Southwest Nigeria together with other plants as a powder mixture to treat patients with breast tumours and inflammation. Aim of the study: There is an increasing interest among researchers in searching for new anticancer drugs from natural resources, particularly plants. This study aimed to investigate the anticancer properties of Acalypha wilkesiana extracts and the characteristics of DNA damage against brain and lung cancer cells. Materials and methods: The antiproliferative activity of Acalypha wilkesiana extracts (ethyl acetate, hexane, and ethanol) was examined on human glioma (U87MG), human lung carcinoma (A549), and human lung fibroblast (MRC5) cells. Results: Cell viability MTT assay revealed that ethyl acetate extract of the plant possessed significant antiproliferative effects against both U87MG (GI50 = 28.03 ± 6.44 μg/ml) and A549 (GI50 = 89.63 ± 2.12 μg/ml) cells (p value 300 μg/ml). The ethanol extract showed no antiproliferative effects on any cell line examined. Haematoxylin & Eosin (H & E) staining and single cell gel electrophoresis (SCGE) comet assay confirmed that plant extract-treated cells underwent apoptosis and not necrosis. SCGE comet assays confirmed that plant extracts caused both single strand (SSB) and double strand (DSB) DNA breaks that led to the execution of apoptosis. Conclusion: The extracts (especially ethyl acetate and hexane) of Acalypha wilkesiana possess valuable cytotoxic effects that trigger apoptosis in U87MG and A549 cancer cells through induction of DNA SSBs and DSBs

Large-scale evolutionary surveillance of the 2009 H1N1 influenza A virus using resequencing arrays

In April 2009, a new influenza A (H1N1 2009) virus emerged that rapidly spread around the world. While current variants of this virus have caused widespread disease, particularly in vulnerable groups, there remains the possibility that future variants may cause increased virulence, drug resistance or vaccine escape. Early detection of these virus variants may offer the chance for increased containment and potentially prevention of the virus spread. We have developed and field-tested a resequencing kit that is capable of interrogating all eight segments of the 2009 influenza A(H1N1) virus genome and its variants, with added focus on critical regions such as drug-binding sites, structural components and mutation hotspots. The accompanying base-calling software (EvolSTAR) introduces novel methods that utilize neighbourhood hybridization intensity profiles and substitution bias of probes on the microarray for mutation confirmation and recovery of ambiguous base queries. Our results demonstrate that EvolSTAR is highly accurate and has a much improved call rate. The high throughput and short turn-around time from sample to sequence and analysis results (30 h for 24 samples) makes this kit an efficient large-scale evolutionary biosurveillance tool

Inhibitory Effect of Duabanga grandiflora on MRSA Biofilm Formation via Prevention of Cell-Surface Attachment and PBP2a Production

Formation of biofilms is a major factor for nosocomial infections associated with methicillin-resistance Staphylococcus aureus (MRSA). This study was carried out to determine the ability of a fraction, F-10, derived from the plant Duabanga grandiflora to inhibit MRSA biofilm formation. Inhibition of biofilm production and microtiter attachment assays were employed to study the anti-biofilm activity of F-10, while latex agglutination test was performed to study the influence of F-10 on penicillin-binding protein 2a (PBP2a) level in MRSA biofilm. PBP2a is a protein that confers resistance to beta-lactam antibiotics. The results showed that, F-10 at minimum inhibitory concentration (MIC, 0.75 mg/mL) inhibited biofilm production by 66.10%; inhibited cell-surface attachment by more than 95%; and a reduced PBP2a level in the MRSA biofilm was observed. Although ampicilin was more effective in inhibiting biofilm production (MIC of 0.05 mg/mL, 84.49%) compared to F-10, the antibiotic was less effective in preventing cell-surface attachment. A higher level of PBP2a was detected in ampicillin-treated MRSA showing the development of further resistance in these colonies. This study has shown that F-10 possesses anti-biofilm activity, which can be attributed to its ability to reduce cell-surface attachment and attenuate the level of PBP2a that we postulated to play a crucial role in mediating biofilm formation

Jerantinine B Enhances the Mitochondria-Mediated Apoptosis by p53 Activation in Human Glioblastoma Cells via a Combination with δ-Tocotrienol

Combined treatment using tocotrienols at low dosage with chemotherapeutic agents has been suggested as an alternative to circumvent the single high-dose associated metabolic degradation and non-selective toxicity of the bioactive compounds. A synergism of combined δ-tocotrienol and jerantinine B in killing brain cancer (U87MG) cells that could potentially be mediated via mitochondrial and death receptor pathways has been demonstrated previously. Therefore, the present study was conducted to explore the mitochondrial pathway for the apoptosis induction in U87MG cells via the combination of δ-tocotrienol and jerantinine B at low concentrations. Individual δ-tocotrienol and combined (δ-tocotrienol and jerantinine B) treatments induced G0/G1, whereas, IC 50 of jerantinine B induced G2/M cell cycle arrests in U87MG cells. This was mediated via the activation of Bid, Bax and cytochrome c activities. Interestingly, only the individual jerantinine B and combined treatments induced p53 activation. These findings suggest that the combined treatment mediates an apoptosis via the mitochondrial pathway potentiated by p53 activation and may rationalize a better treatment for brain cancer in the future

Alkaloid extracts of <i>Ficus</i> species and palm oil-derived tocotrienols synergistically inhibit proliferation of human cancer cells

<div><p>Tocotrienols have been reported to possess anticancer effects other than anti-inflammatory and antioxidant activities. This study explored the potential synergism of antiproliferative effects induced by individual alkaloid extracts of <i>Ficus fistulosa</i>, <i>Ficus hispida</i> and <i>Ficus schwarzii</i> combined with δ- and γ-tocotrienols against human brain glioblastoma (U87MG), lung adenocarcinoma (A549) and colorectal adenocarcinoma (HT-29) cells. Cell viability and morphological results demonstrated that extracts containing a mixture of alkaloids from the leaves and bark of <i>F. schwarzii</i> inhibited the proliferation of HT-29 cells, whereas the alkaloid extracts of <i>F. fistulosa</i> inhibited the proliferation of both U87MG and HT-29 cells and showed synergism in combined treatments with either δ- or γ-tocotrienol resulting in 2.2–34.7 fold of reduction in IC₅₀ values of tocotrienols. The observed apoptotic cell characteristics in conjunction with the synergistic antiproliferative effects of <i>Ficus</i> species-derived alkaloids and tocotrienols assuredly warrant future investigations towards the development of a value-added chemotherapeutic regimen against cancers.</p></div

Reversal of Ampicillin Resistance in MRSA via Inhibition of Penicillin-Binding Protein 2a by Acalypha wilkesiana

The inhibitory activity of a semipure fraction from the plant, Acalypha wilkesiana assigned as 9EA-FC-B, alone and in combination with ampicillin, was studied against methicillin-resistant Staphylococcus aureus (MRSA). In addition, effects of the combination treatment on PBP2a expression were investigated. Microdilution assay was used to determine the minimal inhibitory concentrations (MIC). Synergistic effects of 9EA-FC-B with ampicillin were determined using the fractional inhibitory concentration (FIC) index and kinetic growth curve assay. Western blot experiments were carried out to study the PBP2a expression in treated MRSA cultures. The results showed a synergistic effect between ampicillin and 9EA-FC-B treatment with the lowest FIC index of 0.19 (synergism ≤ 0.5). The presence of 9EA-FC-B reduced the MIC of ampicillin from 50 to 1.56 μg mL−1. When ampicillin and 9EA-FC-B were combined at subinhibitory level, the kinetic growth curves were suppressed. The antibacterial effect of 9EA-FC-B and ampicillin was shown to be synergistic. The synergism is due the ability of 9EA-FC-B to suppress the activity of PBP2a, thus restoring the susceptibility of MRSA to ampicillin. Corilagin was postulated to be the constituent responsible for the synergistic activity showed by 9EA-FC-B

Antibacterial and Antioxidant Activities of Synedrella nodiflora (L.) Gaertn. (Asteraceae)

The hexane, ethyl acetate, ethanol and water extracts of Synedrella nodiflora (L.) Gaertn.(Asteraceae) were assessed for their antibacterial and antioxidant capacities. The antioxidant capacities were evaluated using the ferric reducing antioxidant power (FRAP) and β-carotene bleaching assays. The antimicrobial activities were assessed using the classical pour-plate disc diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and death kinetic assays, against six bacterial strains. The ethanol extract displayed significant antioxidant capacities both in the FRAP and β-carotene bleaching assays. The ethanol extract abrogated the growth of all the bacteria tested. Folin-Ciocalteu and aluminium chloride spectrometry assays indicated the presence phenolic compounds, including flavonoids in the ethanol extract

Pentacyclic and hexacyclic cucurbitacins from Elaeocarpus petiolatus

Four undescribed cucurbitacins, designated as petiolaticins A–D, and four known cucurbitacins were isolated from the bark and leaves of Elaeocarpus petiolatus (Jack) Wall. Their chemical structures were elucidated based on detailed analyses of the NMR and MS data. The absolute configuration of petiolaticin A was also determined by X-ray diffraction analysis. Petiolaticin A represents a cucurbitacin derivative incorporating a 3,4-epoxyfuranyl-bearing side chain, while petiolaticin B possesses a furopyranyl unit fused to the tetracyclic cucurbitane core structure. Petiolaticins A, B, and D were evaluated in vitro against a panel of human breast, pancreatic, and colorectal cancer cell lines. Petiolaticin A exhibited the greatest cytotoxicity against the MDA-MB-468, MDA-MB-231, MCF-7, and SW48 cell lines (IC50 7.4, 9.2, 9.3, and 4.6 μM, respectively). Additionally, petiolaticin D, 16α,23α-epoxy-3β,20β-dihydroxy-10αH,23βH-cucurbit-5,24-dien-11-one, and 16α,23α-epoxy-3β,20β-dihydroxy-10αH,23βH-cucurbit-5,24-dien-11-one 3-O-β-D-glucopyranoside were tested for their ability to inhibit cell entry of a pseudotyped virus bearing the hemagglutinin envelope protein of a highly pathogenic avian influenza virus. Petiolaticin D showed the highest inhibition (44.3%), followed by 16α,23α-epoxy-3β,20β-dihydroxy-10αH,23βH-cucurbit-5,24-dien-11-one (21.0%), and 16α,23α-epoxy-3β,20β-dihydroxy-10αH,23βH-cucurbit-5,24-dien-11-one 3-O-β-D-glucopyranoside showed limited inhibition (9.0%). These preliminary biological assays have demonstrated that petiolaticins A and D possess anticancer and antiviral properties, respectively, which warrant for further investigations