Mimicking effects of cholesterol in lipid bilayer membranes by self-assembled amphiphilic block copolymers.

The effect of cholesterol on biological membranes is important in biochemistry. In this study, a polymer system is used to simulate the consequences of varying cholesterol content in membranes. The system consists of an AB-diblock copolymer, a hydrophilic homopolymer hA, and a hydrophobic rigid homopolymer C, corresponding to phospholipid, water, and cholesterol, respectively. The effect of the C-polymer content on the membrane is studied within the framework of a self-consistent field model. The results show that the liquid-crystal behavior of B and C has a great influence on the chemical potential of cholesterol in bilayer membranes. The effects of the interaction strength between components, characterized by the Flory-Huggins parameters and the Maier-Saupe parameter, were studied. Some consequences of adding a coil headgroup to the C-rod are presented. Results of our model are compared to experimental findings for cholesterol-containing lipid bilayer membranes.

Tilt Modulus of Bilayer Membranes Self-Assembled from Rod-Coil Diblock Copolymers.

Quantitatively understanding membrane fission and fusion requires a mathematical model taking their underlying elastic degrees of freedom, such as the molecule's tilt, into account. Hamm-Kozlov's model is such a framework that includes a tilt modulus along with the bending modulus and Gaussian modulus. This paper investigates the tilt modulus of liquid-crystalline bilayer membranes by applying self-consistent field theory. Unlike the widely used method in molecular dynamics simulation which extracts the tilt modulus by simulating bilayer buckles with various single modes, we introduce a tilt constrain term in the free energy to stabilize bilayers with various tilt angles. Fitting the energy curve as a function of the tilt angle to Hamm-Kozlov's elastic energy allows us to extract the tilt modulus directly. Based on this novel scheme and focused on the bilayers self-assembled from rod-coil diblock copolymers, we carry out a systematic study of the dependence of the tensionless A-phase bilayer's tilt modulus on the microscopic parameters.

Analytical Calculation of the Elastic Moduli of Self-Assembled Liquid-Crystalline Bilayer Membranes.

Liquid-crystalline orders are ubiquitous in membranes and could significantly affect the elastic properties of the self-assembled bilayers. Calculating the free energy of bilayer membranes with different geometries and fitting them to their theoretical expressions allow us to extract the elastic moduli, such as the bending modulus and Gaussian modulus. However, this procedure is time-consuming for liquid-crystalline bilayers. In paper reports a novel method to calculate the elastic moduli of the self-assembled liquid-crystalline bilayers within the self-consistent field theory framework. Based on the asymptotic expansion method, we derive the analytical expression of the elastic moduli, which reduces the computational cost significantly. Numerical simulations illustrate the validity and efficiency of the proposed method.

Anatomic measurement and clinical significance of the middle and lower thoracic segments in normal adults / Medición anatómica e importancia clínica de los segmentos torácico medio e inferior en adultos normales

Thoracic disc herniation (TDH) has high technical difficulty and serious complications, and the clinical anatomy of thoracic intervertebral foramen is less. Collecting 10 adult male cadavers, measuring the longitudinal diameter of the dorsal root ganglion (D1), the transverse diameter of the dorsal root ganglion (D2), horizontal sagittal diameter of the upper edge of the intervertebral disc (S1), the high of intervertebral foramen (H1), the height of articulationes costovertebrales (H2), the height of intervertebral disk (H3), the angel of the dorsal root ganglion (a). The aim of this study is to explore the safe area of middle and lower thoracic section and provide anatomical basis for the selection of operative cannula. Mastering the certain rules of the anatomical structure of the middle and lower thoracic segments, and referring to the above parameters in clinical, is conducive to the selection of the working casing during surgery.

La hernia de disco torácico (TDH) tiene una alta dificultad técnica y complicaciones graves, y la anatomía clínica del agujero intervertebral torácico es menor. Recolectando 10 cadáveres machos adultos, midiendo el diámetro longitudinal del ganglio de la raíz dorsal (D1), el diámetro transversal del ganglio de la raíz dorsal (D2), el diámetro sagital horizontal del borde superior del disco intervertebral (S1), el colmo del intervertebral agujero (H1), la altura de las articulaciones costovertebrales (H2), la altura del disco intervertebral (H3), el ángel del ganglio de la raíz dorsal (α). El objetivo de este estudio es explorar el área segura de la sección torácica media y baja y proporcionar una base anatómica para la selección de la cánula operatoria. Dominar ciertas reglas de la estructura anatómica de los segmentos torácicos medio e inferior, y referirse a los parámetros anteriores en clínica, es propicio para la selección de la carcasa de trabajo durante la cirugía.

Elastic properties of self-assembled bilayer membranes: Analytic expressions via asymptotic expansion.

Bilayer membranes self-assembled from amphiphilic molecules are ubiquitous in biological and soft matter systems. The elastic properties of bilayer membranes are essential in determining the shape and structure of bilayers. A novel method to calculate the elastic moduli of the self-assembled bilayers within the framework of the self-consistent field theory is developed based on an asymptotic expansion of the order parameters in terms of the bilayer curvature. In particular, the asymptotic expansion method is used to derive analytic expressions of the elastic moduli, which allows us to design more efficient numerical schemes. The efficiency of the proposed method is illustrated by a model system composed of flexible amphiphilic chains dissolved in hydrophilic polymeric solvents.

A comparative study of sagittal spinal-pelvic parameters between patients with adolescent idiopathic scoliosis and healthy controls / Un estudio comparativo de los parámetros sagitales de la columna vertebral-pélvic entre pacientes adolescentes con escoliosis idiopática y controles sanos

This study aimed to investigate the sagittal spinal-pelvic morphological changes, as well as the relationship between pelvic anatomical changes and the spinal-pelvic plane in patients with adolescent idiopathic scoliosis (AIS), in order to provide guidelines for orthopedic surgery in AIS. X-ray data were collected for retrospective analysis from 30 patients diagnosed as AIS in the Departments of Radiology at the Second Affiliated Hospital of Inner Mongolia Medical University and the Inner Mongolia International Mongolian Medical Hospital from April 2014 to November 2018, along with 30 normal adolescents as control. Pelvic parameters, including pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS), a spinal parameter, lumbar lordosis (LL), and anatomical parameters, including sacral width (SW) and femoral head- sacrum distance (FH-S), were measured. The spinal-pelvic parameters were compared between AIS patients and normal controls and also between male and female AIS patients. Pearson correlation was performed to analyze correlation between spinal-pelvic parameters and between spinal-pelvic parameters and anatomical parameters in both AIS patients and normal controls. PT was significantly lower in AIS patients than in normal controls (P < 0.05), whereas no significant difference was found in the other spinal-pelvic parameters, i. e. , LL, PI, and SS. There was a significant difference in PT between sexes in AIS patients. SS was significantly correlated with LL in EIA patients (P < 0.05, r > 0.5). SS was significantly correlated with LL and PI, and PT with LL, PI, and SS in normal controls (all P < 0.05), and there was no significant correlation between the other sagittal spinal-pelvic parameters (P > 0.05). FH-S was significantly correlated with LL, PI, SS, and PT in AIS patients (all P < 0.05). AIS affects some of the sagittal spinalpelvic parameters and anatomical parameters. In AIS, there is a significant correlation between the spinal-pelvic parameters, and the anatomical parameter is significantly correlated with multiple spinal-pelvic parameters.

Este estudio tuvo como objetivo investigar los cambios morfológicos sagitales de la columna vertebral-pélvica, así como la relación entre los cambios anatómicos pélvicos y el plano espinal-pélvico en pacientes con escoliosis idiopática adolescente (EIA), con el fin de proporcionar pautas para la cirugía ortopédica en AIS. Se obtuvieron los datos de rayos X para el análisis retrospectivo de 30 pacientes diagnosticados como EIA en los Departamentos de Radiología del hospital Second Affiliated Hospital of Inner Mongolia Medical University y el hospital Inner Mongolia International Mongolian Medical Hospital, desde abril de 2014 hasta noviembre del 2018, junto con 30 adolescentes normales como control. Se midieron los parámetros pélvicos, que incluyeron incidencia pélvica (IP), inclinación pélvica (P) y pendiente sacra (PS), un parámetro espinal, lordosis lumbar (LL) y parámetros anatómicos, que incluyeron el ancho sacro (AS) y la distancia del sacro cabeza femoral (FH-S). Los parámetros espinalpélvicos se compararon entre los pacientes con EIA y los controles normales, como también entre pacientes con EIA masculinos y femeninos. La correlación de Pearson se realizó para analizar la correlación entre los parámetros espinal-pélvicos y entre los parámetros espinal-pélvicos y los parámetros anatómicos tanto en pacientes con EIA como en controles normales. PT fue significativamente menor en pacientes con EIA que en los controles normales (P <0,05), mientras que no se encontraron diferencias significativas en los otros parámetros espinal-pélvicos, i. mi. , LL, PI y SS. Hubo una diferencia significativa en PT en pacientes de ambos sexos con EIA. SS se correlacionó significativamente con LL en pacientes con EIA (P <0,05, r> 0,5). SS se correlacionó significativamente con LL y PI, y PT con LL, PI y SS en controles normales (todos P <0,05), y no hubo correlación significativa entre los otros parámetros sagitales de la columna vertebral-pélvica (P> 0,05) FH-S se correlacionó significativamente con LL, PI, SS y PT en pacientes con EIA (todos P <0,05). EIA afecta algunos de los parámetros sagitales de la columna vertebral-pélvica y los parámetros anatómicos. En EIA, existe una correlación significativa entre los parámetros espinal-pélvicos, y el parámetro anatómico se correlaciona significativamente con múltiples parámetros espinales-pélvicos.

Elastic properties of liquid-crystalline bilayers self-assembled from semiflexible-flexible diblock copolymers.

The mechanical response and shape of self-assembled bilayer membranes depend crucially on their elastic properties. Most of the studies focused on the elastic properties of fluid membranes, despite the ubiquitous presence of membranes with liquid-crystalline order. Here the elastic properties of liquid-crystalline bilayers self-assembled from diblock copolymers composed of a semiflexible block are studied theoretically. Specifically, the self-consistent field theory (SCFT) is applied to a model system composed of semiflexible-flexible diblock copolymers dissolved in flexible homopolymers that act as solvents. The free energy of self-assembled tensionless bilayer membranes in three different geometries, i.e. planar, cylindrical and spherical, is obtained by solving the SCFT equations using a hybrid method, in which the orientation-dependent functions are treated using the spherical harmonics, whereas the position-dependent operators are treated using the compact difference schemes. The bending modulus κM and Gaussian modulus κG of the bilayer are extracted from the free energies. The effects of the molecular parameters of the system, such as the chain rigidity and the orientational interaction, are systematically examined.

MNAT1 is overexpressed in colorectal cancer and mediates p53 ubiquitin-degradation to promote colorectal cancer malignance.

BACKGROUND: MNAT1 (menage a trois 1, MAT1), a cyclin-dependent kinase-activating kinase (CAK) complex, high expresses in various cancers and is involved in cancer pathogenesis. However, mechanisms underlying its regulation in carcinogenesis are unclear. METHODS: The tissue microarray of colorectal cancer (CRC) was used to evaluate MNAT1 expressions in CRC tissues using immunohistochemistry, CRC cell lines were also detected MNAT1 expression using Western-blotting. MNAT1 and shMNAT1 vectors were constructed, and transfected into CRC cells. Cell growths of the transfected cells were observed using MTT and colony formation. The affects of MNAT1 on p53 expression were analyzed using Western-blotting and Real-time PCR. Immunoprecipitation assay was used to analyze the interaction p53 and MNAT1, and Western-blotting was used to test the effects of MNAT1 on p53 downstream molecules. The apoptosis of CRC cells with MNAT1 or shMNAT1 were analyzed using flow cytometry. BABL/c athymic nude mice were used to observe the effect of MNAT1 on CRC cell growth in vivo. RESULTS: MNAT1 was found to be overexpressed in CRC tissues and cells, and MNAT1 expressions in CRC tissue samples were associated with CRC carcinogenesis and poor patient outcomes. MNAT1-knockin increased CRC cell growth and colony formation, and MNAT1-knockdown dramatically decreased cell motility and invasion. MNAT1 physically interacted with p53, MNAT1 also increased the interaction of MDM2 with p53. Strikingly, MNAT1 mediated p53 ubiquitin-degradation. MNAT1 shortened p53 half-life, and ectopic MNAT1 expression decreased p53 protein stability. Moreover, MNAT1 induced RAD51 and reduced p21, cleaved-caspase3, cleaved-PARP and BAX expression. MNAT1 inhibited CRC cell apoptosis. shMANT1 decreased tumor growths in nude mice following p53 increase. CONCLUSION: MNAT1 binds to p53, mediates p53 ubiquitin-degradation through MDM2, increases cell growth and decreases cell apoptosis, and finally promotes CRC malignance. MNAT1 binding to p53 and mediating p53 ubiquitin-degradation axis represents a novel molecular joint in the p53 pathway.

Overexpression of MICAL2, a novel tumor-promoting factor, accelerates tumor progression through regulating cell proliferation and EMT.

Molecule interacting with CasL 2 (MICAL2), a microtubule associated monooxygenase, is involved in cell growth, axon guidance, vesicle trafficking and apoptosis. Recent studies have demonstrated that MICAL2 is highly expressed in tumor and accelerates tumor progression and it is deemed to be a novel tumor-promoting factor. MICAL2 overexpression increases cell proliferation to accelerate tumor growth, and MICAL2 also promotes epithelial-mesenchymal transition (EMT)-related proteins to increase cancer cell metastasis. On mechanism, MICAL2 induces EMT by regulating SRF (serum response factor)/MRTF-A (myocardin related transcription factor A) signaling, Semaphorin/Plexin pathway and inducing ROS (Reactive oxygen species) production. In the present review, we introduced MICAL family, expatiated the structure and functions of MICALs, and summarized the mechanisms of MICAL2 involving tumor progression. The challenges and perspectives for MICAL2 in tumor are also discussed.

Liquid crystalline bilayers self-assembled from rod-coil diblock copolymers.

The structure and phase behaviour of bilayer membranes self-assembled from rod-coil diblock copolymers are studied using the self-consistent field theory, focusing on the occurrence and relative stability of liquid crystalline phases induced by the geometric shape and orientational interaction of the rod-blocks. A variety of liquid crystalline bilayers, corresponding to the smectic phases in bulk systems, are predicted to occur as equilibrium phases of the system. The ordered morphologies and phase behaviour of the system are analyzed. Phase diagrams of the self-assembled bilayers are constructed. The theoretical results provide an understanding of the formation mechanisms of these intricate phases.

Largely different contents of terpenoids in beef red-flesh tangerine and its wild type.

BACKGROUND: Niurouhong (Citrus reticulata Blanco. Niurouhong) (NRH) is a spontaneous beef-red flesh mutant with distinctive flavor compared with its wild type orange-red flesh Zhuhongju (ZHJ). To illustrate the biochemical mechanism of its special flesh color and flavor, fruits at commercial mature stage were used to profile the volatiles in the flavedo and determine the levels of carotenoids, limonoid aglycones and phytohormones in the juice sacs in two seasons. RESULTS: Our results showed the content of total volatile terpenoids in NRH was 1.27-fold that in ZHJ. The components of volatiles were found to be common between the two tangerines. This result indicates that the distinctive flavor of NRH might not be derived from the presence/absence of specific volatiles; instead, it was derived from the altered concentrations or balance of α-citral, ß-citral, 2-cyclohexen-1-one, (S)-3-methyl-6-(1-methylethenyl) and n-hexadecanoic acid. Analyses of the contents of total and specific carotenoids indicated that the beef-red color of NRH flesh might be largely attributed to the over accumulation of ß-cryptoxanthin and ß-carotene. However, lower ABA level was found in NRH than in ZHJ, reflecting a possible feedback regulation of ABA biosynthesis on carotenogenesis and the balance in the metabolism among terpenoids. CONCLUSIONS: Collectively, our study suggested that the MEP pathway was enhanced in NRH tangerine. However, a certain unknown co-regulatory mechanism might be present in the metabolism pathway of secondary metabolites (especially terpenoids) in beef-red flesh mutant. Our study provides new insights into the regulatory network of terpenoid metabolism and mutation mechanism of red-fleshed citrus.

Nucleic acid aptamer application in diagnosis and therapy of colorectal cancer based on cell-SELEX technology.

Nucleic acid aptamers are a class of high-affinity nucleic acid ligands. They serve as "chemical antibodies" since their high affinity and specificity. Nucleic acid aptamers are generated from nucleic acid random-sequence using a systematic evolution of ligands by exponential enrichment (SELEX) technology. SELEX is a process of effectively selecting aptamers from different targets. A newly developed cell-based SELEX technique has been widely used in biomarker discovery, early diagnosis and targeted cancer therapy, particular at colorectal cancer (CRC). Combined with nanostructures, nano-aptamer-drug delivery system was constructed for drug delivery. Various nanostructures functionalized with aptamers are highly efficient and has been used in CRC therapeutic applications. In the present, we introduce a cell- SELEX technique, and summarize the potential application of aptamers as biomarkers in CRC diagnosis and therapy. And some characteristics of aptamer-targeted nanocarriers in CRC have been expatiated. The challenges and perspectives for cell-SELEX are also discussed.

Digital Anatomical Measurement for Anterolateral Fixation of Middle and Lower Thoracic Vertebrae.

BACKGROUND The key to its successful application is to determine the best entry point for the vertebral screw(s). This study aimed to provide a reference for clinical anterolateral fixation through digital measurement of computed tomography (CT) data to identify relevant anatomical positions in the middle and lower thoracic vertebrae (T4-T12) of 30 adults. MATERIAL AND METHODS We performed digital measurement of anatomical positions in the middle and lower thoracic vertebrae (T4-T12) of 30 adults. ABBREVIATIONS: Left height of vertebral body, LHV; Right height of vertebral body, RHV; Anterior height of vertebral body, AHV; Middle height of vertebral body, MHV; Posterior height of vertebral body, PHV; Superior sagittal diameter of vertebral body, SSDV; Superior transverse diameter of vertebral body, STDV; inferior sagittal diameter of vertebral body, ISDV; Inferior transverse diameter of vertebral body, ITDV; (1) Left (right) height of vertebral body, [L(R)HV]; Anterior (middle, posterior) height of vertebral body [A(M,P)HV]; Superior (inferior) sagittal diameter of vertebral body, [S(I)SDV]; Superior (inferior) transverse diameter of vertebral body, [S(I)TDV]. RESULTS The transverse diameters of vertebral bodies were always larger than the sagittal diameter for 3~4 mm. The distance between 2 vertebrae (interval of 1 vertebra) range were (52-56) mm for T4-T7 and (44-48) mm for T8-T12, and the surgeons could collate these data to choose a suitable stick length. CONCLUSIONS Bone graft should prune into laterigrade cuboid, it can recover A-P and bilateral physiological functions load, and the height of the vertebral body increased from T4 to T12.

Experimental Application of Bone Marrow Mesenchymal Stem Cells for the Repair of Intervertebral Disc Annulus Fibrosus.

BACKGROUND This study provides experimental results on the applicability of bone marrow mesenchymal stem cells (BMSCs) for the repair of intervertebral disc annulus fibrosus in rabbits. MATERIAL AND METHODS Thirty healthy rabbits were randomized into an observation group (n=15) and a control group (n=15). Both groups underwent degeneration of intervertebral disc annulus fibrosus. The observation group was treated with a solution of BMSCs and dexamethasone sodium phosphate, while the control group was treated with dexamethasone sodium phosphate only. RESULTS The two groups were compared for efficacy and pathological conditions after treatment. Both disc height index and level of type II collagen in nucleus pulposus were significantly higher in the observation group than in the control group at 2, 4, 8, and 12 weeks after degeneration (p<0.05 for all comparisons). The percentages of grade 0 and grade 1 were significantly higher in the observation group than in the control group (p<0.05 for both grade 0 and 1 comparisons), while the percentage of grade 4 and grade 5 were significantly lower in the observation group than in the control group (p<0.05 for both grade 4 and 5 comparisons). CONCLUSIONS BMSCs cultured in vitro can effectively repair intervertebral disc annulus fibrosus, which is of positive significance, and thus is clinically recommended.

Isolation and characterization of a catalase gene "HuCAT3" from pitaya (Hylocereus undatus) and its expression under abiotic stress.

Abiotic stresses usually cause H2O2 accumulation, with harmful effects, in plants. Catalase may play a key protective role in plant cells by detoxifying this excess H2O2. Pitaya (Hylocereus undatus) shows broad ecological adaptation due to its high tolerance to abiotic stresses, e.g. drought, heat and poor soil. However, involvement of the pitaya catalase gene (HuCAT) in tolerance to abiotic stresses is unknown. In the present study, a full-length HuCAT3 cDNA (1870 bp) was isolated from pitaya based on our previous microarray data and RACE method. The cDNA sequence and deduced amino acid sequence shared 73-77% and 75-80% identity with other plant catalases, respectively. HuCAT3 contains conserved catalase family domain and catalytic sites. Pairwise comparison and phylogenetic analysis indicated that HuCAT3 is most similar to Eriobotrya japonica CAT, followed by Dimocarpus longan CAT and Nicotiana tabacum CAT1. Expression profile analysis demonstrated that HuCAT3 is mainly expressed in green cotyledons and mature stems, and was regulated by H2O2, drought, cold and salt stress, whereas, its expression patterns and maximum expression levels varied with stress types. HuCAT activity increased as exposure to the tested stresses, and the fluctuation of HuCAT activity was consistent with HuCAT3 mRNA abundance (except for 0.5 days upon drought stress). HuCAT3 mRNA elevations and HuCAT activities changes under cold stress were also in conformity with the cold tolerances among the four genotypes. The obtained results confirmed a major role of HuCAT3 in abiotic stress response of pitaya. This may prove useful in understanding pitaya's high tolerance to abiotic stresses at molecular level.

Synthesis and biological evaluation of novel 6-chloro-quinazolin derivatives as potential antitumor agents.

Series of novel derivatives of 6-chloro-quinazolin, which this moiety was linked to a 1,5-diaryl-1,4-pentadien-3-one system, have been synthesized and tested for their antitumor activities in vitro against a panel of three human cancer cell lines (MGC-803, Bcap-37, and PC3 cells). Bioassay results indicated that most of the prepared compounds demonstrated good activities against various cancer cells. 6-chloro-quinazolin derivatives 5a and 5f were the most active members in this study, and experimental results of fluorescent staining and flow cytometry analysis revealed that they could induce apoptosis in MGC-803 and Bcap-37 cells, with apoptosis ratios of 31.7% and 21.9% at 24 h of treatment at 10 µM in MGC-803 cells. Those two quinazoline derivatives could be considered as useful templates for future development to obtain more potent antitumor agents.

Anatomical characteristics of infra-lamina ridge in Chinese population / Características anatómicas del puente infra-laminar en la población china

The aim of our study was to observe the occurrence rate and morphological characteristics of Infra-Lamina ridge (ILR) in Chinese population and provide a comprehensive reference for its clinical implication. Vertebrae columns of 82 sets of Chinese adult skeletons were collected. The shape of ILR was classified into three types; the occurrence of it in different sides and sexes were counted. The length, width, thickness of ILR were measured using a caliper with 0.02 mm accuracy. The ILR was usually found to occur from C7 to L5, with its frequency higher from T8 to 12, and highest at T10being up to 80.5%. There was significant statistical difference to the occurrence rate by side, sex and vertebral level. The largest values in its length and width were from T9 to T12. The ILR at T10 was largest in dimensions, being 4.1±2.1 mm in length and 4.4±2.3 mm in width. The ILR is more frequently detected in female and at the left side, at the lower thoracic spine with a larger dimension.

El objetivo de nuestro estudio fue observar la tasa de incidencia y características morfológicas del puente infra-laminar (PIL) en la población china y ofrecer una referencia completa por su implicación clínica. Se utilizaron 82 series de vértebras pertenecientes a esqueletos adultos chinos. La forma del PIL se clasificó en tres tipos; además se cuantificó la presenciade la misma en diferentes lados y sexos. La longitud, ancho y grosor del PIL se midieron utilizando un caliper con 0,02 mm de precisión. Se encontró que el PIL por lo general se producía desde C7 a L5 , con una mayor frecuencia entre T8 y T12, la más alta en T10 donde alcanzó el 80,5%. No hubo diferencia estadísticamente significativa en la tasa de ocurrencia según lado, sexo y el nivel de la vértebra. Los mayores valores de longitud y ancho fueron de T9 a T12. El PIL en T10 tuvo las mayores dimensiones, con una longitud de 4,1±2,1 mm y ancho de 4,4±2,3 mm. El PIL se detecta con mayor frecuencia en mujeres y la lado izquierdo, con una mayor dimensión en la columna torácica inferior.

Chemical composition and in vitro evaluation of the cytotoxic and antioxidant activities of supercritical carbon dioxide extracts of pitaya (dragon fruit) peel.

BACKGROUND: Hylocereus polyrhizus and Hylocereus undatus are two varieties of the commonly called pitaya fruits, and pitaya fruits have gained popularity in many countries all over the world. However, studies on chemical composition and the nutritional quality of pitaya flesh peel are limited. RESULTS: Extracts of pitaya (H. polyrhizus and H. undatus) peel were extracted by supercritical carbon dioxide extraction, and analyzed by gas chromatography-mass spectrometry analysis. Their cytotoxic and antioxidant activities were investigated. The main components of H. polyrhizus extract were ß-amyrin (15.87%), α-amyrin (13.90%), octacosane (12.2%), γ-sitosterol (9.35%), octadecane (6.27%), 1-tetracosanol (5.19%), stigmast-4-en-3-one (4.65%), and campesterol (4.16%), whereas H. undatus were ß-amyrin (23.39%), γ-sitosterol (19.32%), and octadecane (9.25%), heptacosane (5.52%), campesterol (5.27%), nonacosane (5.02%), and trichloroacetic acid, hexadecyl ester (5.21%). Both of the two extracts possessed good cytotoxic activities against PC3, Bcap-37, and MGC-803 cells (IC50 values ranging from 0.61 to 0.73 mg/mL), and the activities of their main components were also studied. Furthermore, these extracts also presented some radical scavenging activities, with IC50 values of 0.83 and 0.91 mg/mL, respectively. CONCLUSION: This paper provides evidence for studying the chemical composition of supercritical carbon dioxide extracts of pitaya peel and their biological activity.