Hoomin Lee

Antioxidant and antimicrobial efficacy of a biflavonoid, amentoflavone from Nandina domestica in vitro and in minced chicken meat and apple juice food models

A biflavonoid, amentoflavone isolated from Nandina domestica and characterized by NMR spectral-data analyses was assessed for its antioxidant, and antibacterial potential in vitro and in food-model systems. Amentoflavone exhibited potent antioxidant ability (19.21-75.52%) on scavenging DPPH, ABTS, superoxide, and hydroxyl radicals. Fluorescent images confirmed bacterial membrane depolarization of both the tested pathogens Staphylococcus aureus and Escherichia coli, with a significant reduction in cell viabilities at their respective MIC of 62.5 and 125 µg/mL. Increasing rates of membrane permeability observed in 260 nm-absorbing material, potassium ion, extracellular ATP, and relative electrical conductivity assays confirmed antibacterial mechanistic role of amentoflavone as also evidenced by microscopic studies of SEM and TEM. There was a marked inhibitory effect of amentoflavone with a significant reduction in cell counts of S. aureus and E. coli in minced chicken and apple juice at 4 °C, thus suggesting its nutritional enhancing efficacy as a natural antioxidant and antimicrobial agent.

Targeting autophagy in gastrointestinal malignancy by using nanomaterials as drug delivery systems

Autophagy is a conserved catabolic process involving large protein degradation by a ubiquitous autophagosomic signaling pathway, which is essential for cellular homeostasis. It is triggered by environmental factors such as stress, lack of nutrients, inflammation, and eliminating intracellular pathogens. Although the mechanisms underlying autophagy are still unclear, increasing evidence illuminates the magnitude of autophagy in a wide range of physiological processes and human diseases. Simultaneously, research community has focused on the triggering of autophagy by the internalization of engineered nanomaterials, which indicates a new line of revolution in cancer cure. However, most studies on nanoparticle-induced autophagy focus on brain, breast, and cervical cancers; limited reports are available on gastrointestinal (GI) cancers. Therefore, the aim of this mini review is to discuss in detail the role of autophagy in GI malignancy and the status of research on nanoparticle-induced autophagy.

Design and development of caffeic acid conjugated with Bombyx mori derived peptide biomaterials for anti-aging skin care applications

Over the last few centuries, aging-related diseases have become a part of the global health care problem. The skin is essentially more sensitive to aging because it is influenced by environmental exposure and genetic (genetically determined) processes. The use of a suitable cosmetic anti-aging material using a biomolecule with conventionally important medicine can help to protect damaged skin tissue. A new topical cosmetic anti-aging material should simulate the function of an extracellular matrix with its enhanced physiochemical, biological oxidative stress, and antioxidant properties. This study examined the significant features of CA–APPPKK (caffeic acid conjugated with peptide (APPPKK)) to determine if it meets the requirements for a cosmetic anti-aging biomolecule. Non-toxic CA–APPPKK was synthesized using a simple approach and CA stabilized with a peptide to form the new biomaterials. The cytotoxicity of the CA–APPPKK was examined with a CCK-8 assay and a reactive oxygen species (ROS) assay to evaluate the biological applications. CA–APPPKK caused a decrease in cell viability and membrane damage, and the degree of induction was dose dependent. The longevity-extending role of CA–APPPKK was attributed to its anti-oxidative activity and increased oxidative stress resistance. The anti-inflammatory capacity of CA–APPPKK was measured using a NO assay. This new approach indicates that CA–APPPKK is a potentially cosmetic anti-aging biomaterial for the prevention of oxidative stress-induced premature skin ageing and can be used to study aging-related diseases.

Rice callus extracts for enhancing skin wound healing

Enhanced cell migration in the course of wound healing is required to repair damaged skin. We investigated the effects of rice callus extracts on the migration of skin keratinocytes. Rice callus extracts were obtained by using three different methods: pressurized hot water, crude ethanol, and liquid-liquid extractions. The extract obtained by using crude ethanol extraction was more effective in the migration of skin cells than that obtained by pressurized hot water extraction (PHWE). The crude ethanol extract (CEE) was further partitioned by performing liquid-liquid extraction. As phenolics are inhibitory compounds affecting cell migration, we analyzed the total phenolic content of the rice callus extracts. The level of phenolics in the n-hexane partitioned extract (n-HPE) of CEE was lower than that in all other partitioned extracts. The n-HPE was most effective in enhancing cell migration. We analyzed wound healingrelated factors including platelet derived growth factor B (PDGF-B), transforming growth factor beta 1 (TGF-β1), heparin-binding epidermal growth factor (HB-EGF), and fibroblast growth factor 2 (FGF-2) after the treatment of n-HPE. Most of the expressions of cell migration-related growth factors increased, but HB-EGF dramatically increased (6.5-fold) in keratinocytes treated with n-HPE. The results indicate that n-HPE contains more stimulating growth factors or proteins and less cell migration inhibiting factors than the other tested extracts; thus, n-HPE treatment produced the greatest enhancement of cell migration.