Valorization of Spent coffee Grounds: A sustainable resource for Bio-based phase change materials for thermal energy storage.

Spent coffee grounds (SCGs) are waste residues arising from the process of coffee brewing and are usually sent to landfills, causing environmental concerns. SCGs contain a considerable amount of fatty acids and is therefore a promising green alternative bio-based phase change material (PCMs) compared to conventional organic and inorganic PCMs. In this study, the extraction of coffee oil from SCGs was conducted using three different organic solvents-ethanol, acetone, and hexane. The chemical composition, chemical, and thermophysical properties of these coffee oil extracts were studied to evaluate their feasibility as a bio-based PCM. Gas chromatography-mass spectroscopy (GC-MS) analysis indicated that coffee oil contains about 60-80 % of fatty acids while the phase transition temperature of the coffee oil extracts is approximately 4.5 ± 0.72 °C, with latent heat values of 51.15 ± 1.46 J/g as determined by differential scanning calorimetry (DSC). Fourier Transform Infrared Spectroscopy (FTIR) and DSC results of coffee oil extracts after thermal cycling revealed good thermal and chemical stability. An application study to evaluate coffee oil extract as a potential cold therapy modality showed that it can maintain temperatures below normal body temperature for up to 46 min. In conclusion, this work exemplifies the potential of SCGs as a promising green and sustainable resource for bio-based PCMs for low-temperature thermal energy storage applications such as cold-chain transportation and cold therapy.

Tissue engineered plant extracts as nanofibrous wound dressing.

Use of plant extracts for treatment of burns and wound is a common practice followed over the decades and it is an important aspect of health management. Many medicinal plants have a long history of curative properties in wound healing. Electrospun nanofibers provide high porosity with large surface area-to-volume ratio and are more appropriate for cell accommodation, nutrition infiltration, gas exchange and waste excretion. Electrospinning makes it possible to combine the advantages of utilizing these plant extracts in the form of nanofibrous mats to serve as skin graft substitutes. In this study, we investigated the potential of electrospinning four different plant extracts, namely Indigofera aspalathoides, Azadirachta indica, Memecylon edule (ME) and Myristica andamanica along with a biodegradable polymer, polycaprolactone (PCL) for skin tissue engineering. The ability of human dermal fibroblasts (HDF) to proliferate on the electrospun nanofibrous scaffolds was evaluated via cell proliferation assay. HDF proliferation on PCL/ME nanofibers was found the highest among all the other electrospun nanofibrous scaffolds and it was 31% higher than the proliferation on PCL nanofibers after 9 days of cell culture. The interaction of HDF with the electrospun scaffold was studied by F-actin and collagen staining studies. The results confirmed that PCL/ME had the least cytotoxicity among the different plant extract containing scaffolds studied here. Therefore we performed the epidermal differentiation of adipose derived stem cells on PCL/ME scaffolds and obtained early and intermediate stages of epidermal differentiation. Our studies demonstrate the potential of electrospun PCL/ME nanofibers as substrates for skin tissue engineering.

Galangin induces apoptosis of hepatocellular carcinoma cells via the mitochondrial pathway.

AIM: To investigate the mechanism by which galangin, a polyphenolic compound derived from medicinal herbs, induces apoptosis of hepatocellular carcinoma (HCC) cells. METHODS: The 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay was used to measure cell viability. Apoptosis was evaluated by in situ uptake of propidium iodide and Hoechst 33258 and was then detected by fluorescence microscopy. Protein expressions were detected by Western blotting. To confirm the apoptotic pathway mediated by galangin, cells were transfected by bcl-2 gene to overexpress Bcl-2 or siRNA to down-regulate Bcl-2 expression. RESULTS: Galangin (46.25-370.0 micromol/L) exerted an anti-proliferative effect, induced apoptosis, and decreased mitochondrial membrane potential in a dose and time-dependent manner. Treatment with galangin induced apoptosis by translocating the pro-apoptotic protein Bax to the mitochondria, which released apoptosis-inducing factor and cytochrome c into the cytosol. Overexpression of Bcl-2 attenuated galangin-induced HepG2 cell apoptosis, while decreasing Bcl-2 expression enhanced galangin-induced cell apoptosis. CONCLUSION: Our data suggests that galangin mediates apoptosis through a mitochondrial pathway, and may be a potential chemotherapeutic drug for the treatment of HCC.