D. Nedra Karunaratne

Chemical and functional properties of fibre concentrates obtained from by-products of coconut kernel.

The coconut kernel residues obtained after extraction of coconut milk (MR) and virgin coconut oil (VOR) were analysed for their potential as dietary fibres. VOR was defatted and treated chemically using three solvent systems to isolate coconut cell wall polysaccharides (CCWP). Nutritional composition of VOR, MR and CCWPs indicated that crude fibre, neutral detergent fibre, acid detergent fibre and hemicelluloses contents were higher in CCWPs than in VOR and MR. MR contained a notably higher content of fat than VOR and CCWPs. The oil holding capacity, water holding capacity and swelling capacity were also higher in CCWPs than in VOR and MR. All the isolates and MR and VOR had high metal binding capacities. The CCWPs when compared with commercially available fibre isolates, indicated improved dietary fibre properties. These results show that chemical treatment of coconut kernel by-products can enhance the performance of dietary fibre to yield a better product.

Antioxidant Constituents from Xylopia championii.

Abstract Xylopia championii. Hook. f. & Thoms. (Annonaceae) is endemic to Sri Lanka. The antioxidant and antifungal activities of five alkaloids, oxopurpureine, (+)-laudanidine, (−)-discretine, nordicentrine, and dehydrocorytenchine, isolated from the stem bark and stem of X. championii., were studied. The alkaloids, (+)-laudanidine and (−)-discretine, at a concentration of 0.5 mg/mL, exhibited exceptionally high antioxidant activity, where as nordicentrine and dehydrocorytenchine showed moderate activity as compared with the standard antioxidant dl-α -tocopherol in the DPPH assay. All five alkaloids were subjected to an antifungal bioassay against Clodosporium cladosporioides.. Nordicentrine showed the most potent antifungal activity at 6 μ g/spot, and (-)-discretine showed moderate activity at 30.0 μg/spot.

Alginate nanoparticles protect ferrous from oxidation: Potential iron delivery system

A novel, efficient delivery system for iron (Fe2+) was developed using the alginate biopolymer. Iron loaded alginate nanoparticles were synthesized by a controlled ionic gelation method and was characterized with respect to particle size, zeta potential, morphology and encapsulation efficiency. Successful loading was confirmed with Fourier Transform Infrared spectroscopy and Thermogravimetric Analysis. Electron energy loss spectroscopy study corroborated the loading of ferrous into the alginate nanoparticles. Iron encapsulation (70%) was optimized at 0.06% Fe (w/v) leading to the formation of iron loaded alginate nanoparticles with a size range of 15-30nm and with a negative zeta potential (-38mV). The in vitro release studies showed a prolonged release profile for 96h. Release of iron was around 65-70% at pH of 6 and 7.4 whereas it was less than 20% at pH 2.The initial burst release upto 8h followed zero order kinetics at all three pH values. All the release profiles beyond 8h best fitted the Korsmeyer-Peppas model of diffusion. Non Fickian diffusion was observed at pH 6 and 7.4 while at pH 2 Fickian diffusion was observed.

Chitosan-Alginate Nanoparticle System Efficiently Delivers Doxorubicin to MCF-7 Cells

A chitosan-alginate nanoparticle system encapsulating doxorubicin (DOX) was prepared by a novel ionic gelation method using alginate as the crosslinker. These nanoparticles were around 100 nm in size and more stable with higher positive zeta potential and had higher % encapsulation efficiency (95%) than DOX loaded chitosan nanoparticles (DOX Csn NP) crosslinked with sodium tripolyphosphate (STPP). FTIR spectroscopy and thermogravimetric analysis revealed successful loading of DOX. In vitro drug release showed an initial release phase followed by slow release phase with higher cumulative release obtained with DOX loaded chitosan-alginate nanoparticles (DOX Csn-Alg NP). The in vitro cytotoxicity of DOX released from the two nanoparticle systems showed a notable difference on comparison with that of free DOX on the MCF-7 cell line. The SRB assay, AO/EB staining, and fluorescence uptake study indicated that free DOX only showed dose dependent cytotoxicity, whereas both dose and time dependency were exhibited by the two sets of NPs. While both systems show sustained release of DOX, from the cell viability plots, DOX Csn-Alg NPs showed their superiority over DOX Csn NPs. The results obtained are useful for developing DOX Csn-Alg NPs as a sustained release carrier system for DOX.

Antidiabetic Properties, Bioactive Constituents, and Other Therapeutic Effects of Scoparia dulcis.

This review discusses the antidiabetic activities of Scoparia dulcis as well as its antioxidant and anti-inflammatory properties in relation to the diabetes and its complications. Ethnomedical applications of the herb have been identified as treatment for jaundice, stomach problems, skin disease, fever, and kidney stones, reproductory issues, and piles. Evidence has been demonstrated through scientific studies as to the antidiabetic effects of crude extracts of S. dulcis as well as its bioactive constituents. The primary mechanisms of action of antidiabetic activity of the plant and its bioactive constituents are through α-glucosidase inhibition, curbing of PPAR-γ and increased secretion of insulin. Scoparic acid A, scoparic acid D, scutellarein, apigenin, luteolin, coixol, and glutinol are some of the compounds which have been identified as responsible for these mechanisms of action. S. dulcis has also been shown to exhibit analgesic, antimalarial, hepatoprotective, sedative, hypnotic, antiulcer, antisickling, and antimicrobial activities. Given this evidence, it may be concluded that S. dulcis could be promoted among the masses as an alternative and complementary therapy for diabetes, provided further scientific studies on the toxicological and pharmacological aspects are carried out through either in vivo or clinical means.

Effect of Lipid Composition on In Vitro Release and Skin Deposition of Curcumin Encapsulated Liposomes

Liposomal encapsulation improves numerous physiochemical and biological properties of curcumin. The aim of this work was to impart slow release and skin delivery of curcumin via liposomal encapsulation. Liposomes were made using egg yolk phosphatidylcholine as the staple lipid while incorporating polysorbate 80 and stearylamine to prepare hybrid liposomes and positively charged liposomes, respectively. Negatively charged liposomes exhibited the highest encapsulation efficiencies 87.8±4.3% and loading capacities 3.4±0.2%. The sizes of all formulations were about 250 nm, while stearylamine increased the polydispersity index. Positively charged liposomes showed lower degradation temperatures than negatively charged liposomes by 10–15°C, attributable to the presence of stearylamine. The melting temperatures of positively charged liposomes 40–50°C were much higher than those of negatively charged liposomes 14-15°C, which may have affected release and skin deposition behavior of liposomes. The positively charged liposomes exhibited the slowest release of curcumin in phosphate buffered saline pH 6.8 and the release profiles of all liposomal formulations conformed to the Gompertz model. The negatively charged liposomes facilitated the highest skin deposition of curcumin as revealed by studies conducted using excised pig ear skin. Concisely, positively and negatively charged liposomes were optimal for slow release and skin deposition of curcumin, respectively.

Improved Delivery of Caffeic Acid through Liposomal Encapsulation

Photoageing resulting from long term exposure of the skin to UV light can be minimized by scavenging the reactive photochemical intermediates with antioxidants. For effective photoprotection, the antioxidant must overcome the barrier properties of the skin and reach the target site in significant amounts. The present study aims to improve the skin penetration of caffeic acid, a very effective free radical scavenger, by encapsulating in liposomes. Caffeic acid loaded liposomes prepared using the reverse phase evaporation technique showed 70% encapsulation efficiency and size around 100 nm with zeta potential of −55 mV. In vitro diffusion through a dialysis membrane enabled 70% release of encapsulated caffeic acid within 7 h, whereas 95% of free caffeic acid diffused within 4 h in PBS solution pH 7.4. Liposomal caffeic acid permeation through pig skin epidermis in a Franz cell apparatus was 45 % during 7 h. In contrast, free caffeic acid was almost nonpermeable <5% to pig skin during this time. The DPPH assay indicated that skin penetration did not destroy the antioxidant activity of liposomal caffeic acid or free caffeic acid. In conclusion, we confirm that liposomal caffeic acid may be successfully employed as an effective photoprotective agent against UV mediated skin damage.

A Study on Cytotoxic and Apoptotic Potential of a Triterpenoid Saponin (3-O--L-Arabinosyl Oleanolic Acid) Isolated from Schumacheria castaneifolia Vahl in Human Non-Small-Cell Lung Cancer (NCI-H292) Cells

Lung cancer is the major cause of cancer death among men. A number of natural compounds have proven to be useful in the treatmet of lung cancer. This study was aimed to determine cytotoxic and apoptotoic effects of a natural compound 3-O-α-L-arabinosyl oleanolic acid (3-O-L-AO) isolated from Schumacheria castaneifolia in non-small-cell lung cancer (NCI-H292) cells. Cytotoxic effects of 3-O-L-AO were determined by Sulforhodamine B (SRB) assay and apoptotic effects were tested by evaluating (a) apoptotsis related morphological changes, (b) caspase 3/7 activity, and (c) expression of Bax, p53, and survivin genes. Oxidative stress markers (reactive oxygen species (ROS), glutathione-S-transferase (GST), and glutathione (GSH)) were also analysed in 3-O-L-AO treated NCI-H292 cells. 3-O-L-AO exerted potent cytotoxic effects in NCI-H292 cells while being less cytotoxic to normal lung (MRC-5) cells. Exposure to 3-O-L-AO caused upregulation of Bax and p53 and downregulation of survivin in NCI-H292 cells. Activation of caspase 3/7 and morphological features related to apoptosis further confirmed 3-O-L-AO induced apoptosis. Furthermore, elevated ROS and GST levels and decreased GSH levels suggested 3-O-L-AO can induce apoptosis, possibly causing oxidative stress in NCI-H292 cells. Overall results suggest that 3-O-L-AO can be considered as an effective anticancer agent for the treatment of lung cancer.

Antioxidant activity and a new butanolide from the primitive endemic genus Hortonia

The antioxidant activity of MeOH and dichloromethane extracts of the leaves and their alkaloid fractions of the three representative species of the endemic genus Hortonia were evaluated using DPPH radical scavenging bioassay. The results showed that the percentage yield of the basic compounds from all three species was very low. In general, the antioxidant activity of the leaf extracts and their acid washings was very low. It was also determined, contrary to what had been reported, that the alkaloid boldine was not found in detectable amounts in any of the acid washed fractions. Chemical investigations of the three species yielded a new butanolide, which was characterized by NMR and mass spectral data. DOI: http://dx.doi.org/10.4038/jnsfsr.v42i3.7402 J.Natn.Sci.Foundation Sri Lanka 2014 42 (3): 279-282