Direct entry of cell-penetrating peptide can be controlled by maneuvering the membrane curvature.

A biomembrane's role is to be a barrier for interior cytosol from an exterior environment to execute the cell's normal biological functions. However, a water-soluble peptide called cell-penetrating peptide (CPP) has been known for its ability to directly penetrate through the biomembranes into cells (cytolysis) without perturbating cell viability and expected to be a promising drug delivery vector. Examples of CPP include peptides with multiple arginine units with strong cationic properties, which is the key to cytolysis. Here we show the conclusive evidence to support the mechanism of CPP's cytolysis and way to control it. The mechanism we proposed is attributed to biomembrane's physicochemical nature as lamellar liquid crystal (Lα). Cytolysis occurs as the temporal and local dynamic phase transitions from Lα to an undulated lamellar with pores called Mesh1. We have shown this phase transfer of Lα composed of dioleoyl-phosphatidylcholine (DOPC) with water by adding oligo-arginine (Rx) as CPP at the equilibrium. Using giant unilamellar vesicle composed of DOPC as a single cell model, we could control the level of cytolysis of CPP (FITC-R8) by changing the curvature of the membrane through osmotic pressure modulation. The cytolysis of CPP utilizes biomembrane's inherent topological and functional flexibility corresponding to the stimuli.

Traditional uses, phytochemistry, and pharmacology of Ficus hispida L.f.: A review.

ETHNOPHARMACOLOGICAL RELEVANCE: Ficus hispida L.f. (Moraceae) has long been used as a traditional medicine in India, China, Sri Lanka, Australia, and Myanmar in the treatment of diarrhea, ulcer, anemia, diabetes, inflammation, and cancer. AIM OF THE REVIEW: This review provides a systematic comment on the botany, traditional uses, and phytochemical and pharmacological studies of F. hispida, with an aim to make critical update of the current knowledge and obtain opportunities for further therapeutic potential. MATERIALS AND METHODS: The information was derived from scientific literature databases including PubMed, Baidu Scholar, Google Scholar, Web of Science, and Science Direct. Additional information was gathered from books, Ph.D. and M.Sc. dissertations, and unpublished materials. RESULTS AND DISCUSSION: F. hispida is used especially in Chinese and Indian traditional medical systems as a remedy for skin disorders, respiratory diseases, and urinary diseases. Wound healing, anti-inflammatory, antinociceptive, sedative, antidiarrheal, antiulcer, antimicrobial, antioxidant, hepatoprotective, antineoplastic, and antidiabetic activities have been reported for crude extracts and isolated metabolites, but the methodologies in these studies often have inadequate design and low technical quality. More than 76 compounds have been isolated from F.hispida, including sesquiterpenoids and triterpenoids, flavonoids, coumarins, phenylpropionic acids, benzoic acid derivatives, alkaloids, steroids, other glycosides, and alkanes, but the method of bioassay-guided fractionation is seldom applied in the isolation from F. hispida. CONCLUSION: F. hispida is used widely in traditional medicines and has multiple pharmacological effects that could support traditional uses. However, pharmacological studies should be viewed with caution because of the inappropriate experimental design. More in vitro and in vivo research is urgently needed to study the molecular mechanisms and assess the effective and safe dose of F. hispida.

Potent Anti-Proliferation on the Colon Cancer Cell Line (HT-29) of Liposomal Formulations Entrapped with Semi-Purified Job's Tears (Coix lacryma-jobi Linn.) Fractions.

Liposomes, entrapped with Job's Tears fractions, were prepared by the supercritical carbon dioxide fluid (scCO2) technique with and without sonication. Physical characteristics, which were the particle size, zeta potential, vesicular morphology, microviscosity and bioactivities including anti-proliferative, apoptotic and antioxidative activities of the S1L-S5L liposomal systems, were investigated. The potent anti-proliferative activity with the IC50 value of 4.44±2.31 ug/ml in a colon cancer cell (HT-29) was observed in the S5L. S5L also showed the apoptotic activity of 4.45±0.92% in an HT-29 cell. For antioxidative activities, the S3L showed the highest free radical scavenging activity and lipid peroxidation inhibition, whereas the S4L gave the highest metal chelating activity. This study has demonstrated the potent anti-proliferative activity on an HT-29 cell of the S5L liposomal formulation prepared by the scCO2 technique which can be further developed towards a novel anticancer drug.

C21 steroids from Streptocaulon juventas (Lour) Merr. induce apoptosis in HepG2.

Three new C21 steroids, i.e., (3ß,17α,20S)-pregn-5(6)-ene-3, 17, 20-triol-3-O-ß-d-digitalopyranosyl-(1 → 4)-ß-d-digitalopyranoside (4), (3ß,17α,20S)-pregn-5(6)-ene-3, 17, 20-triol-20-O-ß-d-glucopyranosyl-(1 → 6)-ß-d-glucopyranosyl-(1 → 2)-ß-d-digital-opyranoside (8), (3ß, 20R)-pregn-14(15)-ene-3, 20, 21-triol-3-O-ß-d-glucopy-ranoside (10), along with ten known C21 steroids were isolated from Streptocaulon juventas. Their structures were elucidated on the basis of 1D and 2D NMR spectroscopic techniques, mass spectrometry as well as comparison with the literature. All the isolated compounds were screened for their in vitro cytotoxicity against human liver cancer cells (HepG2) and the structure-activity relationships were also analyzed. Moreover, compounds 1-3, 5, 10-12, which displayed cytotoxic activities in HepG2 cells, were tested for the selective index (SI) by the ratio of cytotoxic effect on human hepatocytes (LO2) to that on HepG2. As a result, new compound 10 exhibited a good inhibitory activity against HepG2 with IC50 value 11.7 µM as well as high SI value 3.5. Furthermore, compound 10 could induce HepG2 cells apoptosis by flow cytometry.

Chemical Constituents of the Seed Cake of Camellia oleifera and Their Antioxidant and Antimelanogenic Activities.

There is a growing interest in the exploitation of agricultural byproducts. This study explored the potential beneficial health effects from the main biowaste, tea seed pomace of Camellia oleifera Abel (Theaceae), produced when tea seed is processed. Eighteen compounds were isolated from the 70% EtOH extract of the seed cake of C. oleifera. Their structures were determined by ESI-MS, 1 H- and 13 C-NMR together with literature data. All fractions and compounds were evaluated for the antioxidant and melanogenesis inhibitory activities. As the result, AcOEt fraction has the best in vitro antioxidant and antimelanogenesis activities, compounds 7 - 12 and 15 showed remarkable antioxidant activity, compounds 4, 6, 8, and 15 - 17 exhibited superior inhibitory activities against melanogenesis. Furthermore, tyrosinase inhibitory activity assay suggested that compound 8 could suppress melanogenesis by inhibiting the expression of tyrosinase.

Six underlying health conditions strongly influence mortality based on pneumonia severity in an ageing population of Japan: a prospective cohort study.

BACKGROUND: Mortality prediction of pneumonia by severity scores in patients with multiple underlying health conditions has not fully been investigated. This prospective cohort study is to identify mortality-associated underlying health conditions and to analyse their influence on severity-based pneumonia mortality prediction. METHODS: Adult patients with community-acquired pneumonia or healthcare-associated pneumonia (HCAP) who visited four community hospitals between September 2011 and January 2013 were enrolled. Candidate underlying health conditions, including demographic and clinical characteristics, were incorporated into the logistic regression models, along with CURB (confusion, elevated urea nitrogen, tachypnoea, and hypotension) score as a measure of disease severity. The areas under the receiver operating characteristic curves (AUROC) of the predictive index based on significant underlying health conditions was compared to that of CURB65 (CURB and age ≥ 65) score or Pneumonia severity index (PSI). Mortality association between disease severity and the number of underlying health conditions was analysed. RESULTS: In total 1772 patients were eligible for analysis, of which 140 (7.9%) died within 30 days. Six underlying health conditions were independently associated: home care (adjusted odds ratio, 5.84; 95% confidence interval, CI, 2.28-14.99), recent hospitalization (2.21; 1.36-3.60), age ≥ 85 years (2.15; 1.08-4.28), low body mass index (1.99, 1.25-3.16), neoplastic disease (1.82; 1.17-2.85), and male gender (1.78; 1.16-2.75). The predictive index based on these conditions alone had a significantly or marginally higher AUROC than that based on CURB65 score (0.78 vs 0.66, p = 0.02) or PSI (0.78 vs 0.71, p = 0.05), respectively. Compared to this index, the AUROC of the total score consisting of six underlying health conditions and CURB score (range 0-10) did not improve mortality predictions (p = 0.3). In patients with one or less underlying health conditions, the mortality was discretely associated with severe pneumonia (CURB65 ≥ 3) (risk ratio: 7.24, 95%CI: 3.08-25.13), whereas in patients with 2 or more underlying health conditions, the mortality association with severe pneumonia was not detected (risk ratio: 1.53, 95% CI: 0.94-2.50). CONCLUSIONS: Mortality prediction based on pneumonia severity scores is highly influenced by the accumulating number of underlying health conditions in an ageing society. The validation using a different cohort is necessary to generalise the conclusion.

Potential cancer chemopreventive and anticancer constituents from the fruits of Ficus hispida L.f. (Moraceae).

ETHNOPHARMACOLOGICAL RELEVANCE: Ficus hispida L.f. (Moraceae) has been used as alternative for traditional medicine in the treatment of various ailments including cancer-cure. The aim of this study was to evaluate the cancer chemopreventive and anticancer activities of crude extracts of F. hispida, with the objective to screen the inhibition of Epstein-Barr virus early antigen, and cytotoxic active components, and provide foundation for potential applications of this promising medical plant. MATERIALS AND METHODS: Compounds were isolated from the MeOH extract of F. hispida fruits, and their structure elucidation was performed on the basis of extensive spectroscopic analysis. The isolated compounds were evaluated for their inhibitory activities against the Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol 13-acetate (TPA) in Raji cells, and cytotoxic activities against human cancer cell lines (HL60, A549, SKBR3, KB, Hela, HT29, and HepG2) and a normal cell (LO2) using MTT method. For the compound with potent cytotoxic activity, its apoptosis inducing activity was evaluated by the observation of ROS generation level expression, and membrane phospholipid exposure and DNA fragmentation in flow cytometry. The mechanisms of the apoptosis induction were analyzed by Western blotting. RESULTS: Nineteen compounds, 1-19, including two new isoflavones, 3'-formyl-5,7-dihydroxy-4'-methoxyisoflavone (2) and 5,7-dihydroxy-4'-methoxy-3'- (3-methyl-2-hydroxybuten-3-yl)isoflavone (3), were isolated from the MeOH extract of F. hispida fruits. Five compounds, isowigtheone hydrate (1), 2, 3, 9, and 19, showed potent inhibitory effects on EBV-EA induction with IC50 values in the range of 271-340 molar ratio 32 pmol-1 TPA. In addition, five phenolic compounds, 1-3, 10, and 13, exhibited cytotoxic activity against two or more cell lines (IC50 2.5-95.8µM), as well as compounds 1 and 3 were also displayed high selectivity for LO2/HepG2 (SI 23.5 and 11.8, respectively), while the compound 1-induced ROS generation leads to activated caspases-3, -8, and -9 apoptotic process in HL60 cells. CONCLUSION: This study has established that the MeOH extract of F. hispida fruits contains isoflavones, coumarins, caffeoylquinic acids, along with other compounds including phenolics and steroid glucoside as active principles, and has demonstrated that the chemical constituents of F. hispida may be valuable as potential chemopreventive and anticancer agents.

Melanogenesis-Inhibitory and Cytotoxic Activities of Chemical Constituents from the Leaves of Sauropus androgynus L. Merr. (Euphorbiaceae).

A new steroid, 20-hydroxyisofucosterol (stigmasta-5,24(28)-diene-3ß,20ß-diol) (7), along with six known compounds 1 - 6 were isolated from the MeOH extract of the leaves of Sauropus androgynus L. Merr. (Euphorbiaceae). The structure of new steroid was determined by HR-APCI-MS and various NMR techniques in combination with literature data. Subsequently, their anti-inflammatory, cytotoxic activities against five human cell lines, as well as inhibitory activities against the α-MSH induced melanogenesis on the B16 cell line were evaluated. As the results, steroid compounds, 6 and 7 exhibited moderate cytotoxic to HL60, AZ521, SKBR3, and A549 tumor cell lines (IC50 26.9 - 45.1 µm) with high tumor selectivity for A549 relative to WI38 cell lines (SI 2.6 and 3.0, resp.). And, flavonoid compounds, 4 and 5 exhibited superior inhibitory activities against melanogenesis (67.0 - 94.7% melanin content), even with no or low toxicity to the cells (90.1 - 99.6% cell viability) at the concentrations from 10 to 100 µm. Furthermore, Western blot analysis suggested that compound 5 could inhibit melanogenesis by suppressing the protein expressions of MITF, TRP-1, TRP-2, and tyrosinase.

Three new cardiac glycosides obtained from the roots of Streblus asper Lour. and their cytotoxic and melanogenesis-inhibitory activities.

Three new cardiac glycosides strophanthidin-3-O-α-l-rhamnopyranosyl-(1→4)-6-deoxy-ß-d-allopyranoside (1), 5ßH-16ß-acetylkamaloside (2), and mansonin-19-carboxylic acid (3) along with seven known steroids including five cardiac glycosides were isolated from the methanol extracts of Streblus asper Lour. roots. The structures of these compounds were established by spectroscopic analyses. The cytotoxicities of crude extracts and all the isolated compounds were evaluated against four human cancer cell lines (HL60, A549, AZ521, and SKBR3). Furthermore, the selective index (SI) of each compound was measured by the ratio of cytotoxic effect on a normal cell line (WI38) to the cytotoxic effect on cancer cell line (A549). The results suggested that cardiac glycosides (2, 4, and 6-8) exhibited significant cytotoxicities with IC50 values from 0.01 to 3.77 µM as well as high selective index for WI38/A549 (SI 1.50-24.26), and they displayed superior selectivities when compared with the reference cisplatin (SI 1.09). Preliminary structure-activity relationships (SARs) were also discussed regarding the type of C-10 group in the cardiac glycosides being a crucial factor in determining the cytotoxic activities and regarding the sugar moieties having much less of an active role than the type of C-10 group. In addition, the melanogenesis-inhibitory abilities of these compounds were also evaluated. Cardiac glycosides (3 and 6-8) displayed moderate inhibition effects on melanogenesis with melanin content (MC) of 26.22-74.90% at a concentration of 100 µM, thus showing high cell viability (CV: 77.94-111.70%) compared with that of the reference arbutin (MC: 82.50% and CV: 107.60%). Furthermore, western blot analysis of melanogenesis-related proteins suggested that 3 could inhibit melanogenesis by suppressing the protein expressions of TRP-2 and tyrosinase.

Biological Activities of Phenolics from the Fruits of Phyllanthus emblica L. (Euphorbiaceae).

Seven phenolic compounds, 1 - 7, including a new organic acid gallate, mucic acid 1-ethyl 6-methyl ester 2-O-gallate (7), were isolated from the MeOH extract of the fruits of Phyllanthus emblica L. (Euphorbiaceae). The structures were elucidated on the basis of extensive spectroscopic analysis and comparison with literature data. Upon evaluated for their antioxidant abilities by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) assays. The inhibitory activities against melanogenesis in B16 melanoma cells induced by α-MSH, as well as cytotoxic activities against four human cancer cell lines were also evaluated. All phenolic compounds, 1 - 7, exhibited potent antioxidant abilities (DPPH: IC50 5.6 - 12.9 µm; ABTS: 0.87 - 8.43 µm Trolox/µm; FRAP: 1.01 - 5.79 µm Fe2+ /µm, respectively). Besides, 5 - 7, also exhibited moderate inhibitory activities against melanogenesis (80.7 - 86.8% melanin content), even with no or low toxicity to the cells (93.5 - 101.6% cell viability) at a high concentration of 100 µm. Compounds 1 - 3 exhibited cytotoxic activity against one or more cell lines (IC50 13.9 - 68.4%), and compound 1 with high tumor selectivity for A549 (SI 3.2).

Melanogenesis-Inhibitory and Cytotoxic Activities of Limonoids, Alkaloids, and Phenolic Compounds from Phellodendron amurense Bark.

Four limonoids, 1 - 4, five alkaloids, 5 - 9, and four phenolic compounds, 10 - 13, were isolated from a MeOH extract of the bark of Phellodendron amurense (Rutaceae). Among these, compound 13 was new, and its structure was established as rel-(1R,2R,3R)-5-hydroxy-3-(4-hydroxy-3-methoxyphenyl)-6-methoxy-1-(methoxycarbonylmethyl)indane-2-carboxylic acid methyl ester (γ-di(methyl ferulate)) based on the spectrometric analysis. Upon evaluation of compounds 1 - 13 against the melanogenesis in the B16 melanoma cells induced with α-melanocyte-stimulating hormone (α-MSH), four compounds, limonin (1), noroxyhydrastinine (6), haplopine (7), and 4-methoxy-1-methylquinolin-2(1H)-one (8), exhibited potent melanogenesis-inhibitory activities with almost no toxicity to the cells. Western blot analysis revealed that compound 6 inhibited melanogenesis, at least in part, by inhibiting the expression of protein levels of tyrosinase, TRP-1, and TRP-2 in α-MSH-stimulated B16 melanoma cells. In addition, when compounds 1 - 13 were evaluated for their cytotoxic activities against leukemia (HL60), lung (A549), duodenum (AZ521), and breast (SK-BR-3) cancer cell lines, five compounds, berberine (5), 8, canthin-6-one (9), α-di-(methyl ferulate) (12), and 13, exhibited cytotoxicities against one or more cancer cell lines with IC50 values in the range of 2.6 - 90.0 µm. In particular, compound 5 exhibited strong cytotoxicity against AZ521 (IC50 2.6 µm) which was superior to that of the reference cisplatin (IC50 9.5 µm).

Potent in vivo anticancer activity and stability of liposomes encapsulated with semi-purified Job's tear (Coix lacryma-jobi Linn.) extracts on human colon adenocarcinoma (HT-29) xenografted mice.

The in vivo anticancer activity and stability of liposomes encapsulated with semi-purified Job's tear (Coix lacryma-jobi Linn.) extracts (S5L), prepared by supercritical carbon dioxide fluid technique, on human colon adenocarcinoma (HT29) xenografted mice were investigated. For the stability and the physicochemical characteristics, S5L showed a high stability of pH, good dispersibility, small particle size and stable zeta potential. Liposomes can protect linoleic acid in the extract comparing with the free S5. S5L kept at 4 °C for 3 months showed the highest linoleic acid content of 63.50%, whereas at 45 °C, the lowest linoleic acid content of 42.66% was observed. The anticancer activity and toxicity on xenografted mice were observed for 14 days. At the end of the experiment, the relative tumor volume (RTV) in the S5L-treated xenografted mice showed a significant RTV reduction. The high dose of S5 and S5L were potent with the highest inhibition of tumor growth of 48.67 and 54.75%, which was 86.94% and 97.81% of 5-fluorouracil, respectively. The apoptotic activity was shown in xenografted mice treated with S5 at medium and high dose, S5L, 5-fluorouracil and commercial product. All treated xenografted mice showed no toxic signs and symptoms, abnormality of internal organs histopathology and blood chemistry. This study has demonstrated the high physicochemical stability of liposomes encapsulated with semi-purified Job's tear extract and their potent anticancer activity on human colon adenocarcinoma xenografted model with the potential for further development to anticolon cancer drug.

Potent in vitro anti-proliferative, apoptotic and anti-oxidative activities of semi-purified Job's tears (Coix lachryma-jobi Linn.) extracts from different preparation methods on 5 human cancer cell lines.

ETHONOPHARMACOLOGICAL RELEVANCES: Job's tears (Coix lacryma-jobi Linn.) is commonly used as an herbal medicine. The low incidence of cancer has been observed in the area of China where regularly consume Job's tears. The effects of preparation methods of Job's tears on anti-cancer activities were investigated. Potent in vitro anti-proliferative, apoptotic and anti-oxidative activities of semi-purified Job's tears extracts from different preparation methods on 5 human cancer cell lines comparing with standards and commercial product were observed. AIM OF STUDY: To study the anti-proliferative, apoptotic and anti-oxidative activities of semi-purified Job's tear extracts from different preparation methods on 5 human cancer cell lines. MATERIALS AND METHODS: The crude methanolic extracts of non-cooked, steamed and roasted Job's tears cultivars were prepared and further semi-purified by liquid-liquid extraction techniques. Both of crude and semi-purified extracts were tested for anti-proliferative, apoptotic induction, anti-oxidative activities and phytochemicals content. RESULTS: The highest yields of crude and-purified extracts were 4.60% and 1.46%, respectively. In crude extracts, the steamed whole Thai Black Loei Job's tears (W-TBL-S1) extract showed the highest anti-proliferative activity in mouth epidermal carcinoma cell (KB) at the IC50 of 43.61±0.76µg/ml (0.005 folds of doxorubicin), whereas the roasted whole Laos White Loei Job's tears (W-LWL-R2) extract showed the highest apoptotic activity in cervical adenocarcinoma (HeLa) at 21.52±1.50% (0.22 and 15.05 folds of doxorubicin and commercial product, respectively). After liquid-liquid extraction, almost all of the semi-purified extracts showed increases in anti-proliferative activity. Ethyl acetate fraction of the roasted whole Laos White Loei Job's tears (W-LWL-R2) showed the highest anti-proliferative activity in HeLa cell at the IC50 of 0.97±0.82µg/ml (7.82 and 45.39 folds of doxorubicin and crude extract, respectively) and apoptotic activity of 18.77±6.31% (0.19 folds of doxorubicin). The commercial product showed no anti-proliferative activity in all cell lines but induced apoptosis in HeLa cell at 1.43±0.34%. The butanol and hexane soluble fractions of the roasted whole of Laos White Loei Job's tears (W-LWL-R2) showed the highest free radical scavenging (SC50) and metal chelating activity (MC50) of 0.31±0.06mg/ml (0.64 folds of ascorbic acid) and 0.08±0.01mg/ml (6.37 folds of EDTA), respectively. All ethyl acetate fractions contain high content of carotenoid and tannin, whereas the hexane soluble fraction of the roasted hull of Laos Black Loei Job's tears (H-LBL-R1) showed the highest linoleic acid content of 8.09±0.74% w/w. CONCLUSIONS: This study has demonstrated the potent anti-cancer activity of the semi-purified extracts from roasted Job's tears with high potential for further development to modern anti-cancer drug.

Interfacial and emulsifying properties of soybean peptides with different degrees of hydrolysis.

In this study, the effects of the degree of hydrolysis on the interfacial and emulsifying properties of soybean peptides were evaluated based on surface and interfacial tension, dynamic light scattering (DLS), and freeze-fracture transmission electron microscopy (FF-TEM) analyses. Of the five evaluated soybean peptides (SP95, SP87, SP75, SP49, and SP23), those with higher degrees of hydrolysis (SP95 and SP87) did not exhibit noticeable surface-active properties in water, whereas those with relatively low degrees of hydrolysis (SP75, SP49, and SP23) exhibited remarkable surface tension-lowering activity. The latter set (SP75, SP49, and SP23) also formed giant associates with average sizes ranging from 64.5 nm to 82.6 nm above their critical association concentration (CAC). Moreover, SP23 with the lowest degree of hydrolysis exhibited excellent emulsifying activity for soybean oil, and FF-TEM analysis demonstrated that the emulsions were stabilized by a lamella-like multilayer peptide structure on the oil droplets that prevented coagulation. The peptide with the lowest degree of hydrolysis (SP23) was effective not only for soybean oil emulsification, but also for the emulsification of liquid paraffin and silicon oil that are generally difficult to emulsify.

Surfactant-like properties of an amphiphilic α-helical peptide leading to lipid nanodisc formation.

Nanodiscs are self-assembled discoidal nanoparticles composed of amphiphilic α-helical scaffold proteins or peptides that wrap themselves around the circumference of a lipid bilayer in a beltlike manner. In this study, an amphiphilic helical peptide that mimics helix 10 of human apoA-I was newly synthesized by solid phase peptide synthesis using Fmoc chemistry, and its physicochemical properties, including surface tension, self-association, and solubilization abilities, were evaluated and related directly to nanodisc formation. The synthesized peptide having hydrophobic and hydrophilic faces behaves like a general surfactant, affording a critical association concentration (CAC) of 2.7 × 10(-5) M and a γCAC of 51.2 mN m(-1) in aqueous solution. Interestingly, only a peptide solution above its CAC was able to microsolubilize L-α-dimyristoylphosphatidylcholine (DMPC) vesicles, and lipid nanodiscs with an average diameter of 9.5 ± 2.7 nm were observed by dynamic light scattering and negative stain transmission electron microscopy. Moreover, the ζ potentials of the lipid nanodiscs were measured for the first time as a function of pH, and the values changed from positive (20 mV) to negative (-30 mV). In particular, nanodisc solutions at acidic pH 4 (20 mV) or basic pH 9 (-20 mV) were found to be stable for more than 6 months as a result of the electrostatic repulsion between the particles.

Water-in-oil emulsions prepared by peptide-silicone hybrid polymers as active interfacial modifier: effects of silicone oil species on dispersion stability of emulsions.

We have recently proposed a new general concept regarding amphiphilic materials that have been named as "active interfacial modifier (AIM)." In emulsion systems, an AIM is essentially insoluble in both water and organic solvents; however, it possesses moieties that are attracted to each of these immiscible liquid phases. Hence, an AIM practically stays just at the interface between the two phases and makes the resulting emulsion stable. In this study, the effects of silicone oil species on the dispersion stability of water-in-oil (W/O) emulsions in the presence of an AIM sample were evaluated in order to understand the destabilization mechanism in such emulsion systems. The AIM sample used in this study is an amphiphilic polymer consisting of a silicone backbone modified with hydrocarbon chains and hydrolyzed silk peptides. The Stokes equation predicts that the sedimentation velocity of water droplets dispersed in a continuous silicone oil phase simply depends on the expression (ρ - ρ0)/η assuming that the droplet size is constant (where ρ is the density of the dispersed water phase, ρ0 is the density of the continuous silicone oil phase, and η is the viscosity of the oil phase). The experimental results shown in this paper are consistent with the Stokes prediction: i.e., in the low-viscous genuine or quasi-Newtonian fluid region, the dispersion stability increases in the following order: dodecamethylpentasiloxane (DPS) < decamethylcyclopentasiloxane (D5) ≤ dodecamethylcyclohexasiloxane (D6). This order agrees well with the order obtained by using the expression (ρ - ρ0)/η as DPS > D5 > D6. This indicates that our emulsion system experiences destabilization through sedimentation, but hardly any coalescence occurs owing to the presence of an additional third phase consisting of the AIM that stabilizes the silicone oil/water interface in the emulsions.

Characterization of mannosylerythritol lipids containing hexadecatetraenoic acid produced from cuttlefish oil by Pseudozyma churashimaensis OK96.

Biosurfactants are surface-active compounds produced by microorganisms. Mannosylerythritol lipids (MEL) are promising biosurfactants produced by Ustilaginomycetes, and their physicochemical and biochemical properties differ depending on the chemical structure of their hydrophilic and/or hydrophobic moieties. To further develop MEL derivatives and expand their potential applications, we focused our attention on the use of cuttlefish oil, which contains polyunsaturated fatty acids (e.g., docosahexaenoic acid, C22:6, and eicosapentaenoic acid, C20:5, as the sole carbon source. Among the microorganisms capable of producing MEL, only nine strains were able to produce them from cuttlefish oil. On gas chromatography-mass spectrometry (GC/MS) analysis, we observed that Pseudozyma churashimaensis OK96 was particularly suitable for the production of MEL-A, a MEL containing hexadecatetraenoic acid (C16:4) (23.6% of the total unsaturated fatty acids and 7.7% of the total fatty acids). The observed critical micelle concentration (CMC) and surface tension at CMC of the new MEL-A were 5.7×10⁻6 M and 29.5 mN/m, respectively, while those of MEL-A produced from soybean oil were 2.7×10⁻6 M and 27.7 mN/m, respectively. With polarized optical and confocal laser scanning microscopies, the self-assembling properties of MEL-A were found to be different from those of conventional MEL. Furthermore, based on the DPPH radical-scavenging assay, the anti-oxidative activity of MEL-A was found to be 2.1-fold higher than that of MEL-A produced from soybean oil. Thus, the newly identified MEL-A is attractive as a new functional material with excellent surface-active and antioxidative properties.

Melanogenesis of methyl myristate loaded niosomes in B16F10 melanoma cells.

The objective of this study was to compare the charge effect of methyl myristate loaded in neutral (Brij 72/cholesterol at 7:3), cationic (Brij 72/cholesterol/dimethyl dioctadecyl ammonium bromide at 7:3:0.65) and anionic niosomes (Brij 72/cholesterol/dicetyl phosphate at 7:3:0.65) for physicochemical characteristics, cytotoxicity in fibroblasts and B16F10 melanoma cells as well as melanogenesis induction activity. The maximum loading and percentage entrapment of methyl myristate were 4.5, 90.68 +/- 7.95 in neutral; 11.0, 92.54 +/- 6.32 in cationic and 0.1% w/w, 74.43 +/- 1.86% in anionic niosomes, respectively. All methyl myristate loaded niosomes were in unilamellar structure under transmission electron microscope and in nanosize at initial and after 3-month storage. The percentages of methyl myristate remaining in all niosomes kept at 4 +/- 2, 30 +/- 2 and 45 +/- 2 degrees C for 3 months were about 82, 74 and 72%, respectively, while the dry free methyl myristate indicated 97.82 +/- 1.74, 96.56 +/- 2.91 and 91.39 +/- 4.32%, respectively. Blank neutral, blank cationic and methyl myristate loaded neutral and cationic niosomes exhibited moderate cytotoxicity in fibroblasts and B16F10 melanoma cells at 56.64 +/- 3.19, 59.72 +/- 1.51; 73.81 +/- 2.86, 82.51 +/- 0.20; 47.34 +/- 2.13, 52.67 +/-2.78 and 73.20 +/- 3.49, 84.34 +/- 2.75% cell viability, respectively. Blank anionic and methyl myristate loaded anionic niosomes indicated no cytotoxicity in both cells. Cytotoxic ratio of cell viability in normal and cancer cells of all niosomes indicated no toxic effect to normal cells. Methyl myristate loaded cationic niosomes demonstrated the highest melanin induction with tyrosinase activity of 1.42 and 1.70 folds of the control and 1.14 and 1.59 folds higher than theophylline, respectively. This study has suggested the potential of methyl myristate loaded cationic niosomes for canities treatment.

Peptide-based gemini amphiphiles: phase behavior and rheology of wormlike micelles.

Aqueous binary phase behavior of a peptide-based gemini amphiphile with glutamic acid and lysine as spacer group, acylglutamyllysilacylglutamate (m-GLG-m where m = 12, 14, and 16), has been reported over a wide range of concentration and temperature. Lauroylglutamyllysillauroylglutamate, 12-GLG-12, self-assembles into spherical micelles above critical micelle concentration (CMC). The micellar region extends up to 32 wt %, and an ordering of spherical micelles into micellar cubic phase, I(1), takes place at 33 wt % at 25 °C. The phase transition, I(1) - hexagonal liquid crystal, (H(1)) - lamellar liquid crystal, (L(α)) has been observed with further increase in concentration; moreover, mixed phases are also observed between the pure liquid crystal domains. Similar phases were observed with 16-GLG-16 above 50 °C (Krafft temperature). The partial ternary phase behavior shows that the micellar solutions of m-GLG-m can solubilize a large amount of cationic amphiphile, alkyltrimethylammonium bromide, C(n)TAB, (where n = 14 (TTAB) and 16 (CTAB)) at 25 °C. An addition of C(n)TAB to the aqueous solutions of 16-GLG-16 in a dilute region forms a transparent solution of viscoelastic wormlike micelles at very low concentration (0.25 wt %) even at ambient condition. A mixture of oppositely charged amphiphiles, m-GLG-m and C(n)TAB, exhibits synergism as a result the amphiphile layer curvature, becomes less positive, and favors the transition from sphere to rod to transient networks (wormlike micelles). The gemini amphiphile, 16-GLG-16, forms wormlike micelles at relatively low concentrations compared to others reported so far. Viscosity increases by six orders of magnitude compared to that of pure solvent. The hydrophobic chain length of m-GLG-m and coamphiphile affects the rheology; the maximum viscosity achieved with 16-GLG-16/H(2)O/CTAB is higher than that of 14-GLG-14/H(2)O/CTAB, 12-GLG-12/H(2)O/CTAB, and 16-GLG-16/H(2)O/TTAB systems. These temperature-sensitive systems exhibited viscoelastic behavior described by the Maxwell mechanical model with a single stress relaxation mode.

Structure and dynamics of poly(oxyethylene) cholesteryl ether wormlike micelles: rheometry, SAXS, and cryo-TEM studies.

In this article, we provide direct evidence for 1-D micellar growth and the formation of a network structure in an aqueous system of poly(oxyethylene) cholesteryl ether (ChEO(20)) and lauryl diethanolamide (L-02) by rheometry, small-angle X-ray scattering (SAXS), and cryo-transmission electron microscopy (cryo-TEM). The ChEO(20) self-assembles into spheroid micelles above the critical micelle concentration and undergoes a 1-D microstructural transition upon the incorporation of L-02, which because of its lipophilic nature tends to be solubilized into the micellar palisade layer and reduces the micellar curvature. The elongated micelles entangle with each other, forming network structures of wormlike micelles, and the system shows viscoelastic properties, which could be described by the Maxwell model. A peak observed in the zero-shear viscosity (η(0)) versus L-02 concentration curve shifted toward higher L-02 concentrations and the value of maximum viscosity (η(0 max)) increased with the increasing ChEO(20) mixing fraction with water. We observed that η(0 max) increased by 2 to 4 orders of magnitude as a function of the ChEO(20) concentration. The Maxwell relaxation time (τ(R)) shows a maximum value at a concentration corresponding to η(0 max) (i.e., τ(R) increases with L-02 concentration and then decreases after attaining a maximum value, whereas the plateau modulus (G(0)) shows monotonous growth). These observations demonstrate microstructural transitions in two different modes: L-02 first induces 1-D micellar growth and as a result the viscosity increases, and finally after the system attains its maximum viscosity, L-02 causes branching in the network structures. The microstructure transitions are confirmed by SAXS and cryo-TEM techniques.