Ethyl acetate fraction of Garcina epunctata induces apoptosis in human promyelocytic cells (HL-60) through the ROS generation and G0/G1 cell cycle arrest: A bioassay-guided approach

Number of deaths due to cancer diseases is increasing in the world. There is an urgent need to develop alternative therapeutic measures against the disease. Our study reports the cytotoxicity activity of Garcina epunctata (gutifferae) in human promyelocytic leukemia cells (HL-60) and prostate cancer cells (PC-3) was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Changes in mitochondrial membrane potential (MMP), reactive oxygen species (ROS) and morphological changes associated with apoptosis were examined by flow cytometry and Hoescht staining respectively. The results of in vitro antiproliferative screening of fractions and extract from G. epunctata indicated that three fractions inhibited the viability of PC-3 cells with IC₅₀ varied from 50 to 88 μ/ml while two fractions inhibited the proliferation of HL-60 cells with IC₅₀ range between 47.5 and 12 μg/ml. Among the entire fraction tested, Hex-EtOAc (75:25) showed cytotoxic effects on the two cell lines and EtOAc fraction was most active only HL-60 cells (12 μg/ml). Treatment of HL-60 cells with G. epunctata (20, 50, 100 μg/ml) for 24 h led to a significant dose-dependent increase in the percentage of cells in sub-G1 phase by analysis of the content of DNA in cells, and a number of apoptotic bodies containing nuclear fragments were observed in cells treated with 100 μg/ml. The EtOAc fraction of G. epunctata treatment significantly arrested HL-60 cells at the G0/G1 phase (p < 0.05) and ROS was significantly elevated as well as the loss of membrane mitochondrial potential in a concentration dependant manner. The results demonstrated that the EtOAc fraction of G. epunctata inhibited the proliferation of HL-60 cells, leading to cell cycle arrest and programmed cell death, which was confirmed to occur through the mitochondrial pathway.     

Influence of drying and cooking process on the phytochemical content,antioxidant and hypoglycaemic properties of two bell Capsicum annum L. cultivars

The present study evaluates the influence of drying and cooking processes on the health properties of two bell Capsicum annuum L. cultivars Roggiano and Senise compared with fresh peppers. The content of phytochemicals decreased in the order fresh > dried > dried frying processes. HPLC analysis was applied to quantify five flavonoids from peppers. Apigenin was identified as main constituent. Its content was affected by drying and dried frying processes. The antioxidant activity was evaluated by DPPH, ABTS, β-carotene bleaching test and Fe-chelating activity assay. A comparable radical scavenging activity was observed for both cultivars. Interestingly, frying process did not influenced this property. Roggiano peppers exhibited the highest antioxidant activity using β-carotene bleaching test with IC₅₀ values of 38.1 and 24.9 μg/mL for total extract and n-hexane fraction, respectively. GC–MS analysis of lipophilic fraction revealed the presence of fatty acids and vitamin E as major components. In the inhibition of the carbohydrate-hydrolyzing enzymes fresh Senise peppers exerted the strongest activity against α-amylase with an IC₅₀ value of 55.3 μg/mL. Our results indicate that C. annuum cultivars Roggiano and Senise have an interestingly potential health benefits not influenced by processes that are used before consumption.     

Antiproliferative effects of lectins from Canavalia ensiformis and Canavalia brasiliensis in human leukemia cell lines

The antiproliferative activity of lectins Canavalia ensiformis (ConA) and Canavalia brasiliensis (ConBr) were studied using human leukemia MOLT-4 and HL-60 cell lines. It was revealed that both ConA and ConBr were markedly cytotoxic to cells using MTT and NAC assays. The IC₅₀ values were approximately 3 and 20 μg/mL for ConA and ConBr, respectively, for both MOLT-4 and HL-60 cells. However, in normal human peripheral blood lymphocytes, the lectins were not cytotoxic, even when tested at concentrations as high as 200 μg/ml. Using comet assay, the lectins produced a rate of DNA damage exceeding 80% in MOLT-4 and HL-60 cells. Fluorescence analysis revealed the morphology characteristic of apoptosis, with low concentrations of apoptotic bodies and fragmented DNA (5 μg/ml). Flow cytometric analysis demonstrated an accumulation of cells in the sub-G1 cell cycle that is characteristic of DNA fragmentation, and a decrease in membrane integrity at high concentrations. Lastly, we evaluated the alterations in mitochondrial potential that reduced after treatment with lectins. Our results indicate that ConA and ConBr inhibited cell proliferation selectively in tumor cells and that apoptosis was the main death mechanism. Therefore, lectins can be considered a class of molecules with a high antitumor activity potential.     

Comparative in vitro and ex-vivo myelotoxicity of aflatoxins B1 and M1 on haematopoietic progenitors (BFU-E,CFU-E,and CFU-GM): Species-related susceptibility

Haemato- and myelotoxicity are adverse effects caused by mycotoxins. Due to the relevance of aflatoxins to human health, the present study, employing CFU-GM-, BFU-E- and CFU-E-clonogenic assays, aimed at (i) comparing, in vitro, the sensitivity of human vs. murine haematopoietic progenitors to AFB1 and AFM1 (0.001–50 μg/ml), (ii) assessing whether a single AFB1 in vivo treatment (0.3–3 mg/kg b.w.) alters the ability of murine bone marrow cells to form myeloid and erythroid colonies, and (iii) comparing the in vitro with the in vitro ex-vivo data.We demonstrated (i) species-related sensitivity to AFB1, showing higher susceptibility of human myeloid and erythroid progenitors (IC₅₀ values: about 4 times lower in human than in murine cells), (ii) higher sensitivity of CFU-GM and BFU-E colonies, both more markedly affected, particularly by AFB1 (IC₅₀: 2.45 ± 1.08 and 1.82 ± 0.8 μM for humans, and 11.08 ± 2.92 and 1.81 ± 0.20 μM for mice, respectively), than the mature CFU-E (AFB1 IC₅₀: 12.58 ± 5.4 and 40.27 ± 6.05 μM), irrespectively of animal species, (iii) regarding AFM1, a species- and lineage-related susceptibility similar to that observed for AFB1 and (iv) lack of effects after AFB1 in vivo treatment on the proliferation of haematopoietic colonies.     

Cytotoxic activity of sanguinarine and dihydrosanguinarine in human promyelocytic leukemia HL-60 cells

The benzo[c]phenanthridine alkaloid sanguinarine has been studied for its antiproliferative activity in many cell types. Almost nothing however, is known about the cytotoxic effects of dihydrosanguinarine, a metabolite of sanguinarine. We compared the cytotoxicity of sanguinarine and dihydrosanguinarine in human leukemia HL-60 cells. Sanguinarine produced a dose-dependent decline in cell viability with IC₅₀ (inhibitor concentration required for 50% inhibition of cell viability) of 0.9 μM as determined by MTT assay after 4 h exposure. Dihydrosanguinarine showed much less cytotoxicity than sanguinarine: at the highest concentration tested (20 μM) and 24 h exposure, dihydrosanguinarine decreased viability only to 52%. Cytotoxic effects of both alkaloids were accompanied by activation of the intrinsic apoptotic pathway since we observed the dissipation of mitochondrial membrane potential, induction of caspase-9 and -3 activities, the appearance of sub-G₁ DNA and loss of plasma membrane asymmetry. This aside, sanguinarine also increased the activity of caspase-8. As shown by flow cytometry using annexin V/propidium iodide staining, 0.5 μM sanguinarine induced apoptosis while 1–4 μM sanguinarine caused necrotic cell death. In contrast, dihydrosanguinarine at concentrations from 5 μM induced primarily necrosis, whereas apoptosis occurred at 10 μM and above. We conclude that both alkaloids may cause, depending on the alkaloid concentration, both necrosis and apoptosis of HL-60 cells.     

Cytotoxicity and genotoxicity of phenazine in two human cell lines

Phenazine was recently identified as a drinking water disinfection byproduct (DBP), but little is known of its toxic effects. We examined in vitro cytotoxicity and genotoxicity of phenazine (1.9–123 μM) in HepG2 and T24 cell lines. Cytotoxicity was determined by an impedance-based real-time cell analysis instrument. The BrdU (5-bromo-2′-deoxyuridine) proliferation and MTT ((3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) viability assays were used to examine mechanisms of cytotoxicity. Genotoxicity was determined using the alkaline comet assay. Concentration-dependent cytotoxicity was observed in HepG2 cells, primarily due to an antiproliferative effect (BrdU 24 h IC₅₀: 11 μM; 48 h IC₅₀: 7.8 μM) observed as low as 1.9 μM. T24 cells experienced a minor antiproliferative effect (BrdU 24 h IC₅₀: 47 μM; 48 h IC₅₀: 17 μM). IC₅₀ values for HepG2 proliferation and viability were 54–77% lower compared to T24 cells. In both cell lines, IC₅₀ values for proliferation were 66–90% lower than those for viability. At phenazine concentrations producing equivalent cytotoxicity, HepG2 cells (1.9–30.8 μM) experienced no significant genotoxic effects, while T24 cells (7.7–123 μM) experienced significant genotoxicity at ⩾61.5 μM. While these effects were seen at phenazine concentrations above those found in disinfected water, the persistence of the antiproliferative effect and the differential toxicity in each cell line deserves further study.     

Inhibition of sphingosine kinase-2 ablates androgen resistant prostate cancer proliferation and survival

BackgroundEndogenous sphingolipid signaling has been shown to play an important role in prostate cancer endocrine resistance.MethodsThe novel SphK2 inhibitor, ABC294640, was used to explore SphK signaling in androgen resistant prostate cancer cell death signaling.ResultsIt dose-dependently decreased PC-3 and LNCaP cell viability, IC₅₀ of 28 ± 6.1 μM (p < 0.05) and 25 ± 4.0 μM (p < 0.05), respectively. ABC294640 was more potent in long-term clonogenic survival assays; IC₅₀ of 14 ± 0.4 μM (p < 0.05) in PC-3 cells and 12 ± 0.9 μM (p < 0.05) in LNCaP cells. Intrinsic apoptotic assays failed to demonstrate increased caspase-9 activity. Ki-67 staining demonstrated decreased proliferation by 50 ± 8.4% (p < 0.01) in PC-3 cells.ConclusionsSphK2 inhibition decreases androgen resistant prostate cancer viability, survival, and proliferation independently of the intrinsic apoptotic pathway. Findings are in contrast to recent observations of ABC29460 acting dependently on the intrinsic pathway in other endocrine resistant cancer cell lines.     

Genotoxicity and antileishmanial activity evaluation of Physalis angulata concentrated ethanolic extract

Antileishmanial in vitro tests, as well as Ames and micronucleus assays were performed with a concentrated ethanolic extract of Physalis angulata (EEPA)ResultsEEPA did not present mutagenic effect in Salmonella typhimurium strains at concentration reaching 3000 μg/plate and did not induce mutagenic effects after two oral administrations with a 24 h interval at a dose level of 2000 mg/kg. EEPA presented antileishmanial activity and presented an IC₅₀ value of 5.35 ± 2.50 μg/mL and 4.50 ± 1.17 μg/mL against Leishmania amazonensis and Leishmania braziliensis promastigotes, respectively. In the cytotoxicity test against macrophages, the EEPA had a LC₅₀ of 6.14 ± 0.59 μg/mL. Importantly, the IC₅₀ against L. amazonensis intracellular amastigotes was 1.23 ± 0.11 μg/mL.ConclusionEEPA extract is non-mutagenic and presented a promising pharmacological effect against Leishmania parasites.     

Inhibitory vs. protective effects of N-acetyl-l-cysteine (NAC) on the electromechanical properties of the spontaneously beating atria of the frog (Rana ridibunda): An ex vivo study

The results of this study have shown that N-acetyl-l-cysteine (NAC), a compound used for protection of tissues or cell cultures against the deleterious effects of various environmental pollutants, has certain unusual effects on the contraction of the spontaneously beating atria of the frog isolated in saline (ex vivo): (1) NAC, 6.0 and 10.0 mM, eliminated, in a concentration-dependent manner, the contractile properties of the atria (force and frequency) within minutes, without affecting its electrical properties; (2) the IC₅₀ of NAC for the force was 5.09 ± 1.01 mM (n = 6) [4.98–5.19 mM, 95% confidence interval (CI)], significantly lower than the IC₅₀ for the frequency, 6.15 ± 1.01 mM, (6.02–6.29 mM, 95% CI), indicating that working atria cells are more sensitive to NAC than autorhythmic cells. The no-observed-effect concentration (NOEC) was 1–2 mM; (3) the pattern of NAC-induced inhibition of electromechanical activity was similar to that of verapamil, an indication that NAC possibly affects L-type voltage-gated calcium channels; (4) NAC at 2 mM protected against cadmium-induced inhibition of atria contraction. The IC₅₀ for cadmium was 17.9 ± 1.1 μM (n = 6) (16.9–19.0 μM, 95% CI), while in the presence of 2 mM NAC, it became 123.3 ± 1.0 μΜ (n = 6) (114.8–132.4 μM, 95% CI). The same concentration of NAC failed to exert any protective effects against rotenone (5 μM)-induced inhibition of atria contraction. The protective effects of NAC are probably due to chelation of cadmium, rather than scavenging of oxidants.     

Zinc enhances CDKN2A,pRb1 expression and regulates functional apoptosis via upregulation of p53 and p21 expression in human breast cancer MCF-7 cell

Zinc (Zn) is an essential trace elements, its deficiency is associated with increased incidence of human breast cancer. We aimed to study the effect of Zn on human breast cancer MCF-7 cells cultured in Zn depleted and Zn adequate medium. We found increased cancer cell growth in zinc depleted condition, further Zn supplementation inhibits the viability of breast cancer MCF-7 cell cultured in Zn deficient condition and the IC_25, IC₅₀ value for Zn is 6.2 μM, 15 μM, respectively after 48 h. Zn markedly induced apoptosis through the characteristic apoptotic morphological changes and DNA fragmentation after 48 h. In addition, Zn deficient cells significantly triggered intracellular ROS level and develop oxidative stress induced DNA damage; it was confirmed by elevated expression of CYP1A, GPX, GSK3β and TNF-α gene. Zinc depleted MCF-7 cells expressed significantly (p ≤ 0.001) decreased levels of CDKN2A, pRb1, p53 and increased the level of mdm2 expression. Zn supplementation (IC₅₀ = 15 μM), increased significantly CDKN2A, pRB1 & p53 and markedly reduced mdm2 expression; also protein expression levels of CDKN2A and pRb1 was significantly increased. In addition, intrinsic apoptotic pathway related genes such as Bax, caspase-3, 8, 9 & p21 expression was enhanced and finally induced cell apoptosis. In conclusion, physiological level of zinc is important to prevent DNA damage and MCF-7 cell proliferation via regulation of tumor suppressor gene.     

Anti-inflammatory activity of edible brown alga Saccharina japonica and its constituents pheophorbide a and pheophytin a in LPS-stimulated RAW 264.7 macrophage cells

Anti-inflammatory activity of Saccharina japonica and its active components was evaluated via in vitro inhibitory activities against lipopolysaccharide (LPS)-induced nitric oxide (NO) production, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) expression in RAW 264.7 murine macrophage cells. Since the methanolic extract of S. japonica showed strong anti-inflammatory activity, it was fractionated with several solvents. Among the fractions, the ethyl acetate fraction demonstrated the highest inhibition of LPS-induced NO production (IC₅₀ = 25.32 μg/mL), followed by the CH₂Cl₂ fraction (IC₅₀ = 75.86 μg/mL). Considering the yield and anti-inflammatory potential together, the CH₂Cl₂ fraction was selected for chromatographic separation to yield two active porphyrin derivatives, pheophorbide a and pheophytin a, together with an inactive fucoxanthin. In contrast to fucoxanthin, pheophorbide a and pheophytin a showed dose-dependent inhibition against LPS-induced NO production at nontoxic concentrations in RAW 264.7 cells. Both compounds also suppressed the expression of iNOS proteins, while they did not inhibit the COX-2 expression in LPS-stimulated macrophages. These results indicate that pheophorbide a and pheophytin a are two important candidates of S. japonica as anti-inflammatory agents which can inhibit the production of NO via inhibition of iNOS protein expression. Thus, these compounds hold great promise for use in the treatment of various inflammatory diseases.     

Anticancer,antioxidant and antibiotic activities of mushroom Ramaria flava

Ramaria flava is a species of edible mushroom with some bioactivity. The anticancer, antioxidant and antibiotic activities and chemical composition of R. flava ethanol extract (EE) were evaluated. The present study exhibited that the EE displayed the strongest inhibitory activity against tumor cell MDA-MB-231 with an IC₅₀ value of 66.54 μg/mL in three tested tumor cell lines, and the inhibition percent was 71.66% at the concentration of 200 μg/mL (MTT assay). The total phenolic compounds varied among four fractions of the EE from 6.66 to 61.01 mg gallic acid equivalent (GAE) per g dry weight. Water fraction exhibited high DPPH and OH radical-scavenging activities with low IC₅₀ values of 5.86 and 18.08 μg/mL, respectively. Meanwhile, three phenolic compounds from water fraction were also identified by HPLC. The antibiotic activities of the EE were evaluated against three microorganisms and three fungi strains by means of the agar well diffusion method and the poisoned medium technique, respectively. The EE also showed moderate antibiotic activities. These results suggest that R. flava could hold a good potential source for human health.     

Characterization of estrogenic and androgenic activity of phthalates by the XenoScreen YES/YAS in vitro assay

The presented study investigates and compares the estrogenic and androgenic activities of commonly used diesters of phthalic acid (phthalates) using the XenoScreen YES/YAS assay. Phthalates are commonly used plasticizers in polymers dedicated for i.e. food and drug containers. Since phthalates are not chemically bonded to the polymer, they can leach or migrate from the polymer. Therefore, phthalates are identified as contaminants in a variety of consumer products. Investigation of estrogenic and androgenic activities of phthalates (DEP, DBP, BBP, DEHP and DINP) showed no significant effect of tested substances either on hERα or hAR receptors. Phthalates exhibited strong anti-estrogenic (IC₅₀ for BBP = 8.66 μM, IC₅₀ for DEHP = 3.61 μM and IC₅₀ for DINP = 0.065 μM) and anti-androgenic (IC₅₀ for BBP = 5.30 μM, IC₅₀ for DEHP = 2.87 μM and IC₅₀ for DINP = 0.068 μM) activities.     

Evaluation of in vitro cytotoxicity of one-dimensional chain [Fe(salen)(L)]n complexes against human cancer cell lines

The 1d-polymeric iron(III) complexes [Fe(salen)(μ-L)]_n (1–6), involving a deprotonated form of the N-donor heterocyclic compounds (L) imidazole (complex 1), 1,2,4-triazole (2), benztriazole (3), 5-methyltetrazole (4), 5-aminotetrazole (5) and 5-phenyltetrazole (6), were studied for their in vitro cytotoxic activity against human cancer cell lines including lung carcinoma (A549), cervix epithelial carcinoma (HeLa), osteosarcoma (HOS), malignant melanoma (G361), breast adenocarcinoma (MCF7), ovarian carcinoma (A2780) and cisplatin-resistant ovarian carcinoma (A2780cis). Cytotoxicity in vitro (IC₅₀ = 0.39–0.48 μM) was achieved for 2–6 against A2780 (IC₅₀ of cisplatin equals 11.5 μM) as well as for 5 and 6 against all the tested cells, with IC₅₀ = 2.5–37.7 μM. The Uv–Vis spectroscopic study showed that the complexes are unstable in organic solvents (e.g. dimethyl sulfoxide, dimethylformamide) containing even trace amounts of water (and thus also in the medium, i.e. 0.1% DMF, v/v, used in the MTT assay), where they partially or completely decompose to the mixtures involving, besides [Fe(salen)(μ-L)]_n itself, also the starting compounds [{Fe(salen)}₂(μ-O)] and appropriate organic compound (HL). In efforts to find how the resulting cytotoxicity of the most active compounds 5 and 6 is influenced by this fact, the in vitro cytotoxicity testing of mixtures of reactants [{Fe(salen)}₂(μ-O)] and HL, as well as the respective reactants, was also performed. It has been found that the cytotoxicity of 5 and 6 against all the tested cell lines is probably caused by a combined effect of the individual components presented within the corresponding mixture in the medium used.     

Disruption of the PI3K/AKT/mTOR signaling cascade and induction of apoptosis in HL-60 cells by an essential oil from Monarda citriodora

We have isolated an essential oil from Monarda citriodora (MC) and characterized its 22 chemical constituents with thymol (82%), carvacrol (4.82%), β-myrcene (3.45%), terpinen-4-ol (2.78%) and p-cymene (1.53%) representing the major constituents. We have reported for the first time the chemotherapeutic potential of MC in human promyelocytic leukemia HL-60 cells by means of apoptosis and disruption of the PI3K/AKT/mTOR signaling cascade. MC and its major constituent, thymol, inhibit the cell proliferation in different types of cancer cell lines like HL-60, MCF-7, PC-3, A-549 and MDAMB-231. MC was found to be more cytotoxic than thymol in HL-60 cells with an IC₅₀ value of 22 μg/ml versus 45 μg/ml for thymol. Both MC and thymol induce apoptosis in HL-60 cells, which is evident by Hoechst staining, cell cycle analysis and immuno-expression of Bcl-xL, caspase-3,-8,-9 and PARP-1 cleavage. Both induce apoptosis by extrinsic and intrinsic apoptotic pathways that were confirmed by enhanced expression of death receptors (TNF-R1, Fas), caspase-9, loss of mitochondrial membrane potential and regression of Bcl-2/Bax ratio. Interestingly, both MC and thymol inhibit the downstream and upstream signaling of PI3K/AKT/mTOR pathway. The degree of apoptosis induction and disruption of the PI3K signaling cascade by MC was significantly higher when compared to thymol.     

Cylindrospermopsin,a blue-green algal toxin,inhibited human luteinised granulosa cell protein synthesis in vitro

The blue-green algal toxin cylindrospermopsin (CYN) inhibits protein synthesis, and CYP450 enzymes metabolise CYN to cytotoxic endproducts. Human chorionic gonadotrophin (hCG) stimulates the de novo synthesis of StAR and CYP450 aromatase. Human IVF-derived granulosa cells (GC) (n = 7) were exposed to 0–5 μM CYN ± 1 IU/ml hCG for 2–24 h. After 24 h pre-culture GC responded to hCG by increasing estradiol 17β (E₂) and progesterone (P₄) synthesis. Three micromolar of CYN ± 1 IU/ml hCG for 24 h was not cytotoxic and did not affect basal or hCG-stimulated E₂ or P₄ production, but did inhibit protein synthesis (p < 0.05, n = 4). hCG-stimulated steroidogenesis was not reduced by CYN, suggesting a lack of effect on StAR or CYP450 aromatase protein synthesis. hCG enhanced the effects of CYN on GC protein synthesis. Twenty four hours exposure to 0.1 μM CYN did not affect GC, supporting the establishment of a 0.0024 μM Guideline level for CYN in public water supplies.     

Evaluation of antigenotoxic activity of isoliquiritin apioside from Glycyrrhiza glabra L.

Prevention of manifestation of events characteristic of carcinogenesis is being emphasized a rational strategy to combat cancer. Reactive oxygen species (ROS) play an important role in tumor initiation through oxidative damage of DNA. In search for lead molecules in cancer chemoprevention from natural products, a fraction ‘Rlicca’ isolated from Glycyrrhiza glabra was studied for modulatory effect against hydrogen peroxide and 4-nitroquinoline-N-oxide induced genotoxicity in Escherichia coli PQ37 using SOS chromotest and in human peripheral blood lymphocytes using the Comet assay. The fraction ‘Rlicca’ at a concentration of 191 μM decreased the SOS inducing potency (SOSIP) of hydrogen peroxide (1.0 mM) and NQO (20 μg/ml) by 83.72% and 68.77%, respectively. In the human blood lymphocytes, ‘Rlicca’ reduced the tail moment induced by hydrogen peroxide (25 μM) and NQO (5 μg/ml) by 88.04% and 76.64%, respectively, using the Comet assay. The spectroscopic data of ‘Rlicca’ fraction revealed it to be isoliquiritin apioside, a chalcone oligoglycoside. This is the first report of isoliquiritin apioside with marked potential to combat oxidative stress-induced genotoxicity.     

Intracellular trafficking of nuclear localization signal conjugated nanoparticles for cancer therapy

Doxorubicin (DOX) is an anticancer drug with an intracellular site of action in the nucleus. For high antitumour activity, it should be effectively internalized into the cancer cells and accumulate in the nucleus. In this study, we have prepared a nuclear localization signal conjugated doxorubicin loaded Poly (d,l-lactide-co-glycolide) nanoparticles (NPs), to deliver doxorubicin to the nucleus efficiently. Physico-chemical characterization of these NPs showed that the drug is molecularly dispersed in spherical and smooth surfaced nanoparticles. NPs (～226 nm in diameter, 46% encapsulation efficiency) under in vitro conditions exhibited sustained release of the encapsulated drug (63% release in 60 days). Cell cytotoxicity results showed that NLS conjugated NPs exhibited comparatively lower IC₅₀ value (2.3 μM/ml) than drug in solution (17.6 μM/ml) and unconjugated NPs (7.9 μM/ml) in breast cancer cell line MCF-7 as studied by MTT assay. Cellular uptake studies by confocal laser scanning microscopy (CLSM) and fluorescence spectrophotometer showed that greater amount of drug is targeted to the nucleus with NLS conjugated NPs as compared to drug in solution or unconjugated NPs. Flow cytometry experiments results showed that NLS conjugated NPs are showing greater cell cycle (G2/M phase) blocking and apoptosis than native DOX and unconjugated NPs. In conclusion, these results suggested that NLS conjugated doxorubicin loaded NPs could be potentially useful as novel drug delivery system for breast cancer therapy.     

Brine shrimp toxicity of various polarities leaves and fruits crude fractions of Ziziphus jujuba native to Oman and their antimicrobial potency

Ziziphus jujuba (Z. jujube) is a herb used traditionally for the treatment of different aliment since ancient times, however, the scientific information on this plant is still insufficient. The pure active chemical compounds and crude extracts of Z. jujube can be used in food, formulated pharmaceutical products, natural antioxidant, antibiotics, anticancer agent and preservatives. Therefore, the objective of this work is to determine the cytotoxic and antimicrobial activities of different polarity of crude fractions of locally grown Z. jujube by applying brine shrimp lethality and agar gel disc diffusion bioassay. The cytotoxic result reveals that all prepared crude fractions from the leaves and fruits were lethal to all shrimp larvae at a concentration of 1000 μg/ml. Among the leaves crude fractions, butanol extract showed the highest cytotoxic activity with LC₅₀ value of 8.69 μg/ml, whereas the lowest activity was in chloroform crude extract with LC₅₀ value of 45.12 μg/ml. Similarly, in fruits, the highest activity was in ethyl acetate extract with an LC₅₀ value of 11.62 μg/ml and the lowest was in water extract with an LC₅₀ value of 149.28 μg/ml. The methanol and its corresponding fractions were displayed moderate antimicrobial activity against Gram (+ and ?) bacteria at various concentrations with a zone of inhibition range of 0–17 mm. Therefore, the active polar crude fraction of Z. jujuba or its pure component could be candidates for use as safe, effective and comparatively cheap antibiotics and anticancer agents.     

Synthetic polysulfane derivatives induce cell cycle arrest and apoptotic cell death in human hematopoietic cancer cells

Natural polysulfanes including diallyltrisulfide (DATS) and diallyltetrasulfide (DATTS) from garlic possess antimicrobial, chemopreventive and anticancer properties. However these compounds exhibit chemical instability and reduced solubility, which prevents their potential clinical applicability. We synthesized six DATS and DATTS derivatives, based on the polysulfane motif, expected to exhibit improved physical and chemical properties and verified their biological activity on human leukemia cells.We identified four novel cytotoxic compounds (IC₅₀ values: compound 1, 24.96 ± 12.37 μM; compound 2, 22.82 ± 4.20 μM; compound 3, 3.86 ± 1.64 μM and compound 5, 40.62 ± 10.07 μM, compared to DATTS: IC₅₀: 9.33 ± 3.86 μM). These polysulfanes possess excellent differential toxicity, as they did not affect proliferating mononuclear blood cells from healthy donors.We further demonstrated ability of active compounds to induce apoptosis in leukemia cells by analysis of nuclear fragmentation and of cleavage of effector and executioner caspases. Apoptosis was preceded by accumulation of cells in G2/M phase with a pro-metaphase-like nuclear pattern as well as microtubular alterations. Prolonged and persistent arrest of cancer cells in early mitosis by the benzyl derivative identifies this compound as the most stable and effective one for further mechanistic and in vivo studies.