Materials Science Forum Vol. 981

Abstract: The mosquito Aedes aegypti is an epidemic vector of several diseases such as dengue fever and yellow fever. Several pesticides are used to control the mosquito population. Because of their frequent use, some mosquitoes have developed resistance. In the present study, we evaluated the synergistic mosquito-repellent activity of essential oils from Pelargonium radula, Syzgium aromaticum and Citrus aurantifolia against Aedes aegypti by using Y-tube olfactometer. The oils was subsequently analyzed by using GC–MS. These results clearly reveal that the essential oil of C. aurantifolia served as the most potent repellent agent against Aedes aegypti . The results indicate that three constituents; limonene (19.58%) followed by β–pinene (17.12%), geraniol (13.23%) which comprise a large proportion of the C. aurantifolia are likely responsible for the observed repellent activity.

Abstract: Glycosaminoglycans (GAGs) are long unbranched polysaccharide that composed of repeating disaccharide units. They are classified into heparan sulfate (HS), heparin, chondroitin sulfate (CS), dermatan sulfate (DS), keratan sulfate (KS) and hyaluronic acid (HA). During the last decade, demand of GAGs were getting increased due to their potential uses. Vertebrate animal, commonly cartilaginous mammalian tissue, were potential producer of GAGs and have the higher number of biological activities extracted from sea bass waste. Sea bass waste from Lates calcarifer was used as the raw material to extract crude GAGs. Different part of sea bass waste such as, gills, viscera and air bladders were used. The higher content of crude GAGs in sea bass waste was used in cytotoxic and inflammatory study. Different concentration of extract GAGs from gills were used ranging between 0.16-20 mg/mL. GAGs from sea bass waste (gills) showed dose-dependent cytotoxic activity towards MCF-7 cell line in lower concentration. Meanwhile, for anti-inflammatory study GAGs from sea bass waste (gills) showed dose-dependent manner and also reduce NO production in LPS-stimulated cells. This research study concluded that, GAGs from sea bass waste are the alternative source that can be used for cancer and inflammation study.

Abstract: A real-time impedance-based electrochemistry assay was used for assessing the cytotoxicity effect of water extract Hibiscus Rosa-Sinensis on Vero cell line. In this study, H. rosa-sinensis was extracted by using the water extraction with three different concentration which were 200, 100 and 50 µg/mL. The phytochemical compounds in the extract were analyzed by using the Gas Chromatography-Mass Spectrometry (GC-MS). The GC-MS result showed that the extract contains bioactive compounds such as n-hexadecanoic acid, pentadecanoic acid, phenol, 2,4-bis(1,1-dimethylethyl) and octadecanoic acid that have bioactive properties such as cytotoxic and antioxidant. The cytotoxic effect of the extract on normal cell line was assessed by using Real-Time Cell Analysis (RTCA) instrument. The result showed that there was no significant cytotoxicity effect against Vero cell lines. This result showed that the real-time impedance-based assay can be utilized to monitor changes of the cells and to determine the inhibitory concentration of the extract.

Abstract: Oral caries remains a significant public health problem and affects children with early childhood caries (ECC) and severe early childhood caries (S-ECC). However, the mechanisms of these complex multi-species communities are not well understood. This article systematically reviews the studies involving children with caries to learn the demographics of the subjects, their subjects and types of sample, the methodological approaches undertaken, the main findings, and eventually to make recommendations for future research. A search using a designated search string in the Web of Science resulted in 148 articles. A careful examination of each article based on the inclusion criteria resulted in a final 40 articles. Most of the studies were conducted in the United States and China. The studies involved mostly, but not exclusively, children with primary dentition and were having caries. Different types of subjects were sampled from different racial backgrounds and diseases. Different samples were collected, such as supragingival plaque, saliva and biofilm. Clonal analyses and anaerobic approaches were used to characterise the oral microbiome, including shotgun sequencing, pyrosequencing of 16S rRNA genes, and Pacbio sequencing. Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria were among the phyla commonly reported by the studies. Streptococcus mutans was a key aetiologic agent in the development of caries, besides Veillonella, Prevotella spp. and Lactobacillus spp. Some studies developed models and discussed the applications of oral microbiome in relation to diseases. We recommend further reviews on studies strictly on children with caries and studies involving children only for a better generalisation of the findings. More studies relating oral microbiome with dietary intake and other diseases can also be conducted.

Abstract: Therapeutic properties of the medicinal plant are due to the presence of phytochemical constituents. The phytochemical constituents of Plumeria alba flower were investigated by phytochemical screening assays and gas chromatography-mass spectrometry (GC-MS). The phytochemical screening of hexane, dichloromethane, ethyl acetate, butanol, and aqueous extracts of P. alba flower showed it contains a various concentration of saponins, flavonoids, tannins, steroids, volatile oil and phenolic compounds. Several major chemical constituents that were identified is squalene, bis(2-ethylhexyl) phthalate, methyl (methyl 4-O-methyl-α-d-mannopyranoside) uronate and tricyclo [7.2.0.0(2,6)] undecan-5-ol, 2,6,10,10-tetramethyl- (isomer 2) by using GC-MS technique.

Abstract: In this study, biodegradable scaffolds based on hydroxyethyl cellulose (HEC) (5 wt%) and poly (vinyl alcohol) (PVA) (15 wt%) with different percentages of celullose nanocrystal (CNC) (1 and 7 wt%) were fabricated by lyophilization method to get highly porous scaffolds. These scaffolds were made water insoluble by cross-linking via heat treatment. The morphology and thermal properties of HEC/PVA/CNCs scaffolds were characterized by using Scanning Electron Microscope (SEM) and Thermogravimetric Analysis (TGA). The morphological study showed that both prepared scaffold have highly porous structures with good pore interconnected structure. It was observed that thermal properties of scaffolds increased significantly as the concentration of CNCs increased. Cytotoxicity studies on scaffolds were carried out by utilizing human fetal osteoblast (hFOB) cells using DAPI nuclear stain and then confirmed using SEM. hFOB cells were able to attach and spread on all scaffolds. Incorporated CNCs as reinforcing nanofiller on scaffolds promising a superior functionality in bone tissue engineering.

Abstract: Cellulose as a renewable material has received enormous interest in recent time with an effort to minimize the environmental load from mining earthborn functional materials as well as reducing carbon footprint. This work demonstrates that high quality cellulose could be produced from empty fruit bunch of oil palm plantation and could be developed into nanofibers. A small amount of poly (ε-caprolactone) (PCL) was added to the EFB driven cellulose acetate (CA) to develop them as nanofibers by electrospinning technique; this composition was further enhanced by adding curcumin, which is a natural anti-inflammatory, and compared their morphology, structure, mechanical and surface properties.

Abstract: Hibiscus rosa-sinensis which belongs to the family Malvaceae, is a national flower of Malaysia. This glabrous tree can usually grow around 1 to 3 meters tall. The objective of present study was to categorize the essential oil constituent of flowers and leaves extract using different extraction method namely Soxhlet and hydrodistillation. The essential oil obtained from Soxhlet (10.75%) and hydrodistillation (11.40%) were subjected to Gas Chromatography-Mass Spectrometry (GC-MS) for determination of bioactive compounds. The GC-MS analysis was carried out by Agilent 7980A series GC instrument and DB-1MS capillary column with the dimensions of 30 m × 0.25 mm. A total of 21 and 20 compounds were identified for Soxhlet and hyrodistillation technique, respectively. Major compound found in essential oil for Soxhlet apparatus method was (Z,Z,Z)-9-12,15-Octadecatrienoic acid, methyl ester (23.59%) while for hydrodistillation was 1-Methylene-2b-hydroxymethyl-3,3-dimethyl-4b-(3-methylbut-2-enyl)-cyclohexane (16.57%). The presence of numerous bioactive compounds provides insights to the potential of the Hibiscus rosa-sinensis in pharmaceutical industry.

Abstract: Twelve probiotic Lactobacillus strains for poultry were characterised by amplified ribosomal DNA restriction analysis (ARDRA) using Sau3AI, TaqI, HaeIII and AluI restriction endonucleases. Species-specific and strain-specific restriction patterns were observed from the bacterial strains. Numerical analysis of composite analysis of ARDRA exhibited D value of 0.8456. Whereas, the caculated D values of ARDRA patterns generated by Sau3AI, TaqI, HaeIII and AluI were 0.8309, 0.8382,0.8088 and 0.8088, repectively. Composite analysis of ARDRA was the most discriminative method when compared to the individual analysis. ARDRA could distinguished L. reuteri C 10 and L. panis C 17 into single strains. The 16S rRNA gene restriction patterns were also able to group L. gallinarum I 16 and I 26 into single strains. Lactobacillus brevis I 12, I 23, I 25, I 211 and I 218 seem to be multiple clones of the same bacterial strain as are L. reuteri C 1 and C 16. ARDRA is a valuable fingerprinting method to discriminate probiotic Lactobacillus strains.

Abstract: Candida species are known human pathogens that have caused high morbidity and mortality among affected individuals. Candida albicans can switch forms from yeast to hyphae, in which both forms are virulent. Due to its commensal status in normal human microflora, C. albicans poses a virtual threat to humankind because of their dimorphism ability under opportunistic environmental conditions. Because of the increased usage of prophylactic antifungal agents in the treatment of candidiasis, reports of Candida species developing antifungal resistance are increasing. Recent observations of cross-reaction between different classes of antifungal drugs that could yield multidrug-resistant pathogenic Candida species are concerns that need to be urgently addressed.