Natural Sesquiterpene Lactones Enhance Oxacillin and Gentamicin Effectiveness Against Pathogenic Bacteria Without Antibacterial Effects on Beneficial Lactobacilli

This is a report on the synergistic interactions (SIs) between melampolide‐type sesquiterpene lactones 1–8 from Acanthospermum hispidum DC., and oxacillin or gentamicin, against four pathogenic strains of Staphylococcus aureus and Enterococcus faecalis; two of them were multi‐resistant strains obtained from chronic infectious processes. Our results showed that all associations of 1–8 with antibiotics (ATBs) are more effective than pure ATBs to control pathogenic strains of S. aureus and E. faecalis. The most relevant SIs were observed when the major lactone of A. hispidum, acanthospermal B [5], was combined with gentamicin (protein synthesis inhibitor) against an ex vivo culture of methicillin‐resistant S. aureus SAR 1, displaying a significant MIC reduction in 5 (312.5 to 78.1 µg/mL), and gentamicin (120 µg/mL to 3 µg/mL). Compound 4 improved the antibiotic potency of oxacillin (cell wall synthesis inhibitor) against ampicillin‐resistant E. faecalis (60 µg/mL to 1.5 µg/mL). It is important to remark that three beneficial lactobacilli were resistant to 1–8 and their mixtures with gentamicin or oxacillin in effective concentrations against pathogenic bacteria. Synergism between ATBs and phytochemicals is a therapeutically helpful concept to improve ATB efficacy and prevent resistance. The present results show that selective SIs occur between melampolides and gentamicin or oxacillin, and open a new field of research. Copyright © 2015 John Wiley & Sons, Ltd.     

Flavonoids from Sophora moorcroftiana and their Synergistic Antibacterial Effects on MRSA

Synergy is now a widely recognized approach that has direct applicability for new pharmaceuticals. The ethanolic extract of the aerial parts of the herb Sophora moorcroftiana showed significant antibacterial activity against drug‐resistant Staphylococcus aureus, and its minimum inhibitory concentration (MIC) was 8 µg/mL. In a phytochemical study of the extract, five flavonoids were obtained. However, the isolates exhibited antibacterial activity in the range of 32–128 µg/mL, which was weaker than the extract. In combination with antibiotics, the antibacterially inactive compound genistein (1) and diosmetin (4) showed significant synergistic activity against drug‐resistant S. aureus. In combination with norfloxacin, genistein (1) reduced the MIC to 16 µg/mL and showed synergy against strain SA1199B with a fractional inhibitory concentration index (FICI) of 0.38. With the antibiotics norfloxacin, streptomycin and ciprofloxacin, diosmetin (4) showed synergy against SA1199B, RN4220 and EMRSA‐15, with FICI values of 0.38, 0.38 and 0.09, respectively. In an efflux experiment to elucidate a plausible mechanism for the observed synergy, genistein showed marginal inhibition of the NorA efflux protein. Copyright © 2013 John Wiley & Sons, Ltd.     

Inhibition of bacterial growth and biofilm production by constituents from Hypericum spp

Biofilm embedded bacterial pathogens such as Staphylococcus spp., Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii are difficult to eradicate and are major sources of bacterial infections. New drugs are needed to combat these pathogens. Hypericum is a plant genus that contains species known to have antimicrobial properties. However, the specific constituents responsible for the antimicrobial properties are not entirely known, nor have most compounds been tested as inhibitors of biofilm development. The investigation presented here tested seven secondary metabolites isolated from the species Hypericum densiflorum, Hypericum ellipticum, Hypericum prolificum, and Hypericum punctatum as inhibitors of bacterial growth and biofilm production. Assays were conducted against Staphylococcus epidermidis, Staphylococcus aureus, clinical methicillin‐resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter baumannii. Five of the seven compounds demonstrated growth inhibition against the Gram‐positive bacteria with minimum inhibitory concentrations (MIC) ranging from 1.95 µg/mL to 7.81 µg/mL. Four of the secondary metabolites inhibited biofilm production by certain Gram‐positive strains at sub‐MIC concentrations. Copyright © 2011 John Wiley & Sons, Ltd.     

Antitubercular and Antibacterial Activity of Quinonoid Natural Products Against Multi‐Drug Resistant Clinical Isolates

Multi‐drug resistant Mycobacterium tuberculosis and other bacterial pathogens represent a major threat to human health. In view of the critical need to augment the current drug regime, we have investigated therapeutic potential of five quinonoids, viz. emodin, diospyrin, plumbagin, menadione and thymoquinone, derived from natural products. The antimicrobial activity of quinonoids was evaluated against a broad panel of multi‐drug and extensively drug‐resistant tuberculosis (M/XDR‐TB) strains, rapid growing mycobacteria and other bacterial isolates, some of which were producers of β‐lactamase, Extended‐spectrum β‐lactamase (ESBL), AmpC β‐lactamase, metallo‐beta‐lactamase (MBL) enzymes, as well as their drug‐sensitive ATCC counterparts. All the tested quinones exhibited antimycobacterial and broad spectrum antibacterial activity, particularly against M. tuberculosis (lowest MIC 0.25 µg/mL) and Gram‐positive bacteria (lowest MIC <4 µg/mL) of clinical origin. The order of antitubercular activity of the tested quinonoids was plumbagin > emodin ~ menadione ~ thymoquinone > diospyrin, whereas their antibacterial efficacy was plumbagin > menadione ~ thymoquinone > diospyrin > emodin. Furthermore, this is the first evaluation performed on these quinonoids against a broad panel of drug‐resistant and drug‐sensitive clinical isolates, to the best of our knowledge. Copyright © 2013 John Wiley & Sons, Ltd.     

In Vitro Antibacterial Activity and Synergistic Antibiotic Effects of Phlorotannins Isolated from Eisenia bicyclis Against Methicillin‐Resistant Staphylococcus aureus

Six phlorotannins, isolated from Eisenia bicyclis, were evaluated for antibacterial activity against methicillin‐resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentrations (MIC) of the compounds were in the range 32 to 64 µg/mL. Phlorofucofuroeckol‐A (PFF) exhibited the highest anti‐MRSA activity, with an MIC of 32 µg/mL. An investigation of the interaction between these compounds and the β‐lactam antibiotics ampicillin, penicillin, and oxacillin revealed synergistic action against MRSA in combination with compound PFF. To our knowledge, this is the first report on the anti‐MRSA activity of phlorotannins from E. bicyclis. The results obtained in this study suggest that the compounds derived from E. bicyclis can be a good source of natural antibacterial agents against MRSA. Copyright © 2012 John Wiley & Sons, Ltd.     

Evaluation of Turkish seaweeds for antiprotozoal, antimycobacterial and cytotoxic activities

As part of our continuing research on seaweeds, crude MeOH extracts of two green, three brown and six red algae collected from Marmara, Black, Aegean and Mediterranean Seas were screened. Four parasitic protozoa, i.e. Plasmodium falciparum, Trypanosoma brucei rhodesiense, T. cruzi, Leishmania donovani and the tubercle bacillus Mycobacterium tuberculosis were used as test organisms for the in vitro assays. The selective toxicity of the extracts was also determined against mammalian L6 cells. All seaweed extracts were active against T. brucei rhodesiense; the Dasya pedicellata extract was the most potent (IC₅₀ value 0.37 µg/mL). The same extract also weakly inhibited the growth of T. cruzi (IC₅₀ 62.02 µg/mL). All seaweed extracts also showed leishmanicidal activity (IC₅₀ values 16.76–69.98 µg/mL). The majority of the extracts also exhibited antiplasmodial potential and the most potent extracts were those from D. pedicellata (IC₅₀ 0.38 µg/mL), Codium bursa (IC₅₀ 1.38 µg/mL) and Caulerpa rasemosa (IC₅₀ 3.12 µg/mL). One brown and two red algal extracts showed some weak activity against Mycobacterium tuberculosis (MIC values 125–256 µg/mL). Except for the extract of Dasya pedicellata, none of the extracts displayed any cytotoxicity. This is the second study investigating the antiprotozoal activities of Turkish marine algae and identifies Dasya pedicellata, an understudied algal species, as a candidate for further studies. Copyright © 2010 John Wiley & Sons, Ltd.     

Activity of Scottish Plant,Lichen and Fungal Endophyte Extracts against Mycobacterium aurum and Mycobacterium tuberculosis

With tuberculosis the leading bacterial killer worldwide and other mycobacterial diseases on the increase, the search for new antimycobacterial agents is timely. In this study, extracts from plants, lichens and fungal endophytes of Scottish provenance were screened for activity against Mycobacterium aurum and M. tuberculosis H₃₇Rv. The best activity against M. aurum was observed for extracts of Juniperus communis roots and Cladonia arbuscula (MIC = 4 µg/mL), and a fungal endophyte isolated from Vaccinium myrtillus (MIC = 8 µg/mL). The best activity against M. tuberculosis was observed for extracts of C. arbuscula, Empetrum nigrum, J. communis roots, Calluna vulgaris aerial parts, Myrica gale roots and stems (93 to 99% inhibition at 100 µg/mL). Potent antitubercular activity (90 to 96% inhibition at 100 µg/mL) was also observed for the ethanol extracts of Xerocomus badius, Chalciporus piperatus, Suillus luteus and of endophytes isolated from C. vulgaris, E. nigrum, Vaccinium vitis‐idaea and V. myrtillus. The results obtained this study provide, in part, some scientific basis for the traditional use of some of the selected plants in the treatment of tuberculosis. They also indicate that fungal endophytes recovered from Scottish plants are a source of antimycobacterial agents worthy of further investigation. Copyright © 2009 John Wiley & Sons, Ltd.     

Quinolone Alkaloids from Fructus Euodiae Show Activity Against Methicillin‐Resistant Staphylococcus aureus

Fructus Euodiae is used in Traditional Chinese Medicine to treat infection. In this study, four of the quinolone alkaloids isolated from Fructus Euodiae showed activity against methicillin‐resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentrations (MIC) were 8–128 µg/mL, which were equivalent to or lower than the control antibiotics, oxacillin, erythromycin and tetracycline (MIC ≥128 µg/mL). Among these isolated quinolone alkaloids, evocarpine with a 13 carbon alkenyl chain substituent at position‐2 showed the best activity against MRSA. This study has demonstrated the potential of quinolone alkaloids from Fructus Euodiae as anti‐MRSA compounds and supports the traditional use of the fruit as a treatment for bacterial infections. Copyright © 2013 John Wiley & Sons, Ltd.     

Two New Xanthones from Hypericum sampsonii and biological activity of the isolated compounds

Phytochemical investigation of the CH₂Cl₂ extract of the aerial part of Hypericum sampsonii yielded two new prenylated xanthones, hypericumxanthone A and B, together with three known xanthones. Their structures were elucidated by analysis of physical and spectral (UV, IR, mass and NMR) data and comparison of spectroscopic data with those reported previously. All these compounds were evaluated for in vitro antibacterial activity against methicillin‐resistant Staphylococcus aureus (MRSA). Two new compounds were also tested for their cytotoxicity against human breast (MCF‐7), hepatoma (HepG2), colon (HT‐29) and lung (A549) tumour cell lines. Two new compounds showed moderate antibacterial activities at minimum inhibitory concentrations (MIC) of 16 and 32 µg/mL, respectively, whereas the positive standard antibacterial drug, vancomycin, showed an MIC of 8 µg/mL. The other compounds were inactive against MRSA. In addition, hypericumxanthone B showed weak inhibitory activities against four human tumour cell lines. Copyright © 2010 John Wiley & Sons, Ltd.     

Drug Resistance Reversal Potential of Isoliquiritigenin and Liquiritigenin Isolated from Glycyrrhiza glabra Against Methicillin‐Resistant Staphylococcus aureus (MRSA)

Isoliquiritigenin (ISL) and liquiritigenin (LTG) are structurally related flavonoids found in a variety of plants. Discovery of novel antimicrobial combinations for combating methicillin‐resistant Staphylococcus aureus (MRSA) infections is of vital importance in the post‐antibiotic era. The present study was taken to explore the in vitro and in vivo combination effect of LTG and ISL with β‐lactam antibiotics (penicillin, ampicillin and oxacillin) against mec A‐containing strains of MRSA. Minimum inhibitory concentration (MIC) of both LTG and ISL exhibited significant anti‐MRSA activity (50–100 µg/mL) against clinical isolates of MRSA. The result of in vitro combination study showed that ISL significantly reduced MIC of β‐lactam antibiotics up to 16‐folds [∑ fractional inhibitory concentration (FIC) 0.312–0.5], while LTG reduced up to 8‐folds (∑FIC 0.372–0.5). Time kill kinetics at graded MIC combinations (ISL/LTG + β‐lactam) indicated 3.27–9.79‐fold and 2.59–3.48‐fold reduction in the growth of clinical isolates of S. aureus respectively. In S. aureus‐infected Swiss albino mice model, combination of ISL with oxacillin significantly (p < 0.05, p < 0.01, p < 0.001) lowered the systemic microbial burden in blood, liver, kidney, lung and spleen tissues in comparison with ISL, oxacillin alone as well as untreated control. Considering its synergistic antibacterial effect, we suggest both ISL and LTG as promising compounds for the development of novel antistaphylococcal combinations. Copyright © 2016 John Wiley & Sons, Ltd.     

Antielastase and free radical scavenging activities of compounds from the stems of Cornus kousa

Bioassay‐guided investigation of the stems of Cornus kousa led to the isolation of 12 compounds such as four triterpenoids: betulinic acid (1), maslinic acid (2), arjunolic acid (3), 3‐isoarjunolic acid (4), four flavanoids; catechin (5), epi‐catechin (6), 2‐hydroxynaringenin (7), 2‐hydroxynaringenin‐7‐O‐β‐d ‐glucopyranoside (8), two ellagic acid derivatives; 3,4,3′‐tri‐O‐methylellagic acid (9), 3,4‐di‐O‐methylellagic acid (10), a daucosterol (11) and a sucrose derivative; (3′‐O‐p‐coumaroyl)‐β‐d ‐fructofuranosy‐(2?1)‐(6‐O‐p‐coumaroyl)‐α‐d ‐glucopyranoside (12). Their structures were elucidated on the basis of spectroscopic studies as well as by comparison with available data in the literature. The free radical scavenging activity and elastase inhibition activity were investigated for the development of antiaging ingredients as a raw material for use in cosmetics. Among these compounds, compounds 1, 2 and 8 showed significant elastase inhibition activity and IC₅₀ was 10.81 µg/mL, 21.21 µg/mL and 44.63 µg/mL, respectively, on porcine pancreatic elastase, whereas compounds 5, 6, 7 and 8 showed significant free radical scavenging activity and SC₅₀ was 8.37 µg/mL, 9.31 µg/mL, 9.23 µg/mL and 17.45 µg/mL, respectively. Copyright © 2007 John Wiley & Sons, Ltd.     

In vitro Antitubercular Activity of 3‐Deoxysappanchalcone Isolated From the Heartwood of Caesalpinia sappan Linn.

Responsible for nearly 1.5 million deaths every year, the infectious disease tuberculosis remains one of the most serious challenges to global health. The emergence of multidrug‐resistant tuberculosis and, more recently, extensively drug‐resistant tuberculosis poses a significant threat in our effort to control this epidemic. New drugs are urgently needed to combat the growing threat of antimicrobial resistance. To achieve this goal, we screened approximately 500 species of medicinal plant methanol extracts and their solvent partitioned fractions for potential inhibitors of Mycobacterium tuberculosis growth. Using microdilution screening, the ethyl acetate solvent partitioned fraction from the heartwood of Caesalpinia sappan exhibited strong antitubercular activity. We isolated the active compound and identified it as 3‐deoxysappanchalcone. The extracted 3‐deoxysappanchalcone possessed activity against both drug‐susceptible and drug‐resistant strains of M. tuberculosis at MIC₅₀s of 3.125–12.5 μg/mL in culture broth and MIC₅₀s of 6.25–12.5 μg/mL inside macrophages and pneumocytes. 3‐Deoxysappanchalcone was also found to act in partial synergy with streptomycin/ethambutol against M. tuberculosis H37Rv. 3‐Deoxysappanchalcone had no cytotoxicity against the A549 cell line up to a concentration of 100 μg/mL (selectivity index > 8–32). Further studies are warranted to establish the in vivo effect and therapeutic potential of 3‐deoxysappanchalcone. Copyright © 2017 John Wiley & Sons, Ltd.     

Antimycobacterial Activity and Low Cytotoxicity of Leaf Extracts of Some African Anacardiaceae Tree Species

Treatment of tuberculosis (TB) is a challenge because of multidrug‐resistant and extremely drug‐resistant strains of Mycobacterium tuberculosis. Plant species contain antimicrobial compounds that may lead to new anti‐TB drugs. Previous screening of some tree species from the Anacardiaceae family revealed the presence of antimicrobial activity, justifying further investigations. Leaf extracts of 15 Anacardiaceae tree species were screened for antimycobacterial activity using a twofold serial microdilution assay against the pathogenic Mycobacterium bovis and multidrug resistant M. tuberculosis and rapidly growing mycobacteria, Mycobacterium smegmatis, Mycobacterium fortuitum and Mycobacterium aurum. The vaccine strain, M. bovis and an avirulent strain, H37Ra M. tuberculosis, were also used. Cytotoxicity was assessed using a colorimetric assay against Vero kidney, human hepatoma and murine macrophage cells. Four out of 15 crude acetone extracts showed significant antimycobacterial activity with minimum inhibitory concentration varying from 50 to 100 µg/mL. Searsia undulata had the highest activity against most mycobacteria, followed by Protorhus longifolia. M. fortuitum was the strongest predictor of activity against multidrug‐resistant TB (correlation coefficient = 0.65). Bioautography against M. aurum and M. fortuitum worked well as indicators of the Rf values of active compounds yielding strong zones of inhibition. The leaf extracts of S. undulata and P. longifolia had more than ten different antimycobacterial compounds and had low cytotoxicity with LC₅₀ values above 100 µg/mL. Copyright © 2016 John Wiley & Sons, Ltd.     

Antiparasitic,nematicidal and antifouling constituents from Juniperus berries

A bioassay‐guided fractionation of Juniperus procera berries yielded antiparasitic, nematicidal and antifouling constituents, including a wide range of known abietane, pimarane and labdane diterpenes. Among these, abieta‐7,13‐diene (1) demonstrated in vitro antimalarial activity against Plasmodium falciparum D6 and W2 strains (IC₅₀ = 1.9 and 2.0 µg/mL, respectively), while totarol (6), ferruginol (7) and 7β‐hydroxyabieta‐8,13‐diene‐11,12‐dione (8) inhibited Leishmania donovani promastigotes with IC₅₀ values of 3.5–4.6 µg/mL. In addition, totarol demonstrated nematicidal and antifouling activities against Caenorhabditis elegans and Artemia salina at a concentration of 80 µg/mL and 1 µg/mL, respectively. The resinous exudate of J. virginiana afforded known antibacterial E‐communic acid (4) and 4‐epi‐abietic acid (5), while the volatile oil from its trunk wood revealed large quantities of cedrol (9). Using GC/MS, the two known abietanes totarol (6) and ferruginol (7) were identified from the berries of J. procera, J. excelsa and J. phoenicea. Copyright © 2008 John Wiley & Sons, Ltd.     

In vitro Antimicrobial Activity of Royleanone Derivatives Against Gram‐Positive Bacterial Pathogens

Infections caused by multiresistant bacterial pathogens are a significant problem worldwide, turning the search for natural compounds to act as alternatives to antibiotics of major importance. The aim of the present study was to investigate the in vitro antimicrobial activity of 7α‐acetoxy‐6β‐hydroxyroyleanone (1), isolated from Plectranthus grandidentatus (Lamiaceae), and 11 additional royleanone abietane derivatives of 1 (2–12) against important Gram‐positive human bacterial pathogens. Results showed that the aromatic and alkylic esters 2, 3 and 5 are more active than 1 against Enterococcus and Staphylococcus (minimum inhibitory concentration (MIC) values ranging from 0.98 to 62.50 µg/mL). Moreover, 7α‐acetoxy‐6β‐hydroxy‐12‐O‐(4‐chloro)benzoylroyleanone (2) gave rise to a new antibacterial‐prototype (MIC values of 3.91–15.63 µg/mL against Staphylococcus and of 0.98–3.91 µg/mL against Enterococcus). The results showed that the compounds under analysis also present antimicrobial activity against resistant bacteria. The hydrophobic extra‐interactions with bacterial targets seem to play an important role on the activity of royleanones derivatives. Copyright © 2013 John Wiley & Sons, Ltd.     

Antimicrobial,antioxidant and anti‐inflammatory activity of young shoots of the smoke tree,Cotinus coggygria Scop

In this study, we investigated the antimicrobial activity of the young shoots of the smoke tree, Cotinus coggygria Scop., Anacardiaceae. The acetone extract and the derived ethyl acetate fraction effectively inhibited the growth of Gram‐positive and Gram‐negative bacteria (MIC 25–200 µg/ml), while the chloroform fraction showed pronounced activity against the yeast Candida albicans (MIC 3.12 µg/ml). The ethyl acetate fraction exhibited a significant ferric‐reducing ability (10.7 mmol Fe²⁺/g extract), a very high DPPH radical scavenging activity (SC₅₀ = 1.7 µg/ml) and inhibition of lipid peroxidation (IC₅₀ = 41.8 µg/ml). High amounts of total phenolics (929.8 mg/g), tannins (833.8 mg/g) and flavonoids (35.5 mg/g) were determined in the ethyl acetate fraction, which also exerted significant anti‐inflammatory (76.7%) and cytotoxic effects (IC₅₀ = 15.6 µg/ml). Copyright © 2012 John Wiley & Sons, Ltd.     

Antioxidant/Antibacterial Activities of a Topical Phytopharmaceutical Formulation Containing a Standardized Extract of Baccharis incarum,an Extremophile Plant Species from Argentine Puna

The antimicrobial and antioxidant activities of standardized extracts of Baccharis incarum in 60° and 80° ethanol and of a phytopharmaceutical formulation obtained from them were measured. Baccharis tinctures showed antimicrobial activity against clinically isolated antibiotic resistant Staphylococcus aureus and Enterococcus faecalis, with MIC values of 40–80 µg GAE/mL. Both tinctures exhibited ABTS^●+ scavenging activity with SC₅₀ values between 1.6 and 4.0 µg GAE/mL. The tinctures were not genotoxic in the Salmonella assay. For this reason, the tincture in 60° ethanol was incorporated into a topical pharmaceutical formulation (Hydrogel/ Carbopol® 934). The phytopharmaceutical formulation also showed antibacterial and antioxidant activities in the in vitro assays. The hydrogel showed microbiological, chemical, physical and functional stability during storage at room temperature. Studies that measure drug release as a determination of bioavailability were also carried out using the Franz diffusion cell (FC). The results demonstrated the release of two bioactive compounds (chlorogenic acid and 4′,5‐dihydroxy‐3′,3,6,7,8‐pentamethoxyflavone) from the phytotherapic preparation in HPLC studies of FC receptor solution. In consequence, the phytopreparation applied topically could be used to treat skin and soft tissue infection produced by methicillin‐resistant Staphylococcus aureus (MRSA) or Enterococcus faecalis and opens new opportunities for the use of active natural ingredients in the cosmeceutical field as antiacne and antioxidant. Copyright © 2012 John Wiley & Sons, Ltd.     

1‐methyl malate from Berberis integerrima fruits enhances the antibacterial activity of ampicillin against Staphylococcus aureus

The enhancement of the antibacterial activity of ampicillin by different extracts of Berberis integerrima fruits was evaluated against Staphylococcus aureus. Disk diffusion and agar dilution methods were used to determine the antibacterial activity of ampicillin in the absence and presence of different plant extracts or various fractions eluted by column chromatography. A clinical isolate of S. aureus was used as a test strain. The active component of B. integerrima fruits involved in the enhancement of ampicillin activity was purified and identified as 1‐methyl malate using different spectroscopic methods. Both the ethanol extract of B. integerrima fruits and 1‐methyl malate enhanced the antibacterial activity of ampicillin. The total extract as well as 1‐methyl malate increased the antibacterial activity of ampicillin against the test strain. The potency of ampicillin against the test strain was increased 64‐fold when tested with a sub‐toxic concentration of total extract of B. integerrima fruits. Also, 1‐methyl malate increased the bactericidal activity of ampicillin. In the presence of 2 mg/mL of 1‐methyl malate the MIC of ampicillin for S. aureus decreased from 128 to 1 µg/mL (128‐fold). Copyright © 2009 John Wiley & Sons, Ltd.     

Damnacanthal from the Congolese Medicinal Plant Garcinia huillensis has a Potent Preferential Cytotoxicity against Human Pancreatic Cancer PANC‐1 Cells

Screening of eight Congolese medicinal plants showed that the CHCl₃ and MeOH extracts of Aframomum melegueta (PC₅₀ = 47.8 µg/mL and 13.8 µg/mL, respectively) and CHCl₃ extracts of Garcinia huillensis (PC₅₀ = 17.8 µg/mL) and Securidaca longepedunculata (PC₅₀ = 23.4 µg/mL) had preferential cytotoxicity against human pancreatic cancer PANC‐1 cells under nutrient‐deprived conditions. The active constituents of the CHCl₃ extract of G. huillensis were examined and 12 known anthraquinones were identified. Among them, damnacanthal (1) caused preferential necrotic cell death of PANC‐1 and PSN‐1 cells under nutrient‐deprived and serum‐sensitive conditions (PC₅₀ = 4.46 µm and 3.77 µm , respectively). Copyright © 2012 John Wiley & Sons, Ltd.     

Antiviral and anticancer activities of 13(E)‐labd‐13‐ene‐8α,15‐diol isolated from Brachyglottis monroi

The antiviral activity of 13(E)‐labd‐13‐ene‐8α,15‐diol (1), isolated from Brachyglottis monroi, was examined against human rhinovirus 2 (HRV2) and 3 (HRV3), and the anticancer activity on human cancer cells (A549 and Hep2). Compound (1) showed strong anti‐HRV2 and HRV3 activity with a 50% inhibitory concentration (IC₅₀) of 2.68 and 0.87 µg/mL, respectively, and a 50% cytotoxicity concentration (CC₅₀) of 59.45 µg/mL. Ribavirin only showed anti‐HRV3 activity with an IC₅₀ of 30.48 µg/mL and a CC₅₀ > 100 µg/mL. The addition of compound (1) to HRV‐infected HeLa cells directly reduced the formation of visible cytopathic effect (CPE) and it directly interacted with HRV particles. Furthermore, A549 and Hep2 cells incubated with 32 µg/mL of compound (1) for 48 h exhibited antilung and antilaryngeal cancer activities, with a viability of less than 50%. These results suggest that compound (1) may be used as a potential antiviral and anticancer agent. Copyright © 2009 John Wiley & Sons, Ltd.