Gallotannin Improves the Photoaged-Related Proteins by Extracellular Signal-Regulated Kinases/c-Jun N-Terminal Kinases Signaling Pathway in Human Epidermal Keratinocyte Cells.

Tannins are a type of polyphenols found in several fruits such as grapes and berries, and nuts such as aronias and acorns. Both hydrolyzable tannins and condensed tannins are referred to as tannins. Among the hydrolyzable tannins, gallotannin has a strong antioxidative property and is known to protect the skin by inhibiting the precursors of elastolytic enzymes. However, its mechanism of protection against ultraviolet B (UVB) damage in human fibroblasts and keratinocytes has not yet been elucidated. In this study, we investigate the antioxidant and antiaging effect of gallotannin on UVB-irradiated human cells by studying its effect on extracellular signal-regulated kinases/c-Jun N-terminal kinases (EKRs/JNKs) signaling related to cell growth and differentiation/stress apoptosis. The results showed that gallotannin improved collagen synthesis, reduced metalloproteinase-1 (MMP-1) expression in a dose-dependent manner, and downregulated MMP-1 levels through the ERK/JNK signaling pathway in UVB-irradiated human cells. Gallotannin also increased glutathione but did not increase transforming growth factor beta 1, which induces fibrosis. We propose that gallotannin is a novel agent for protection against UVB, and acts as an antiaging agent that can be used in food, pharmaceuticals, and cosmetics.

5-α Reductase inhibitory effect and astringent activity of green apple rind extract on human keratinocytes and fibroblast cells.

Unripe green apples contain condensed tannins at 10 times higher levels than ripe apples. Tannin not only has strong antioxidant activity, but also an astringent property. In this study, we investigated the effects of green apple rind (GAR) extracts in reducing facial pores and sebum secretion. Among the GAR extracts, the 70% ethanol GAR extract showed the highest antioxidant activity and tannin content. Hence, it was further fractionated with different solvents. Among these rind solvent fractions, the ethyl acetate fraction of the extract (GAR-E) showed astringent activity. Additionally, it exhibited inhibitory effects on 5-α reductase, and induced type 1 collagen and involucrin synthesis. These results suggest that GAR-E can be applied in cosmetics to reduce facial pore size and sebum secretion.

Synthesis and dual biological effects of hydroxycinnamoyl phenylalanyl/prolyl hydroxamic acid derivatives as tyrosinase inhibitor and antioxidant.

We previously reported that caffeoyl-amino acidyl-hydroxamic acid (CA-Xaa-NHOH) acted as both a good antioxidant and tyrosinase inhibitor, in particular when caffeic acid was conjugated with proline or amino acids having aromatic ring like phenylalanine. Here, various hydroxycinnamic acid (HCA) derivatives were further conjugated with phenylalanyl hydroxamic acid and prolyl hydroxamic acid (HCA-Phe-NHOH and HCA-Pro-NHOH) to study the structure and activity relationship as both antioxidants and tyrosinase inhibitors. When their biological activities were evaluated, all HCA-Phe-NHOH and HCA-Pro-NHOH exhibited enhanced antioxidant activity compared to HCA alone. Moreover, derivatives of caffeic acid, ferulic acid, and sinapic acid inhibited lipid peroxidation more efficiently than vitamin E analogue (Trolox). In addition, derivatives of caffeic acid and sinapic acid efficiently inhibited tyrosinase activity and reduced melanin content in melanocytes Mel-Ab cell.

Primary malignant fibrous histiocytoma of the kidney.

Primary renal malignant fibrous histiocytoma is a rare tumor of the kidney. It is clinically and radiologically indistinguishable from a renal cell carcinoma. Even following radical surgery, the tumor shows a strong predilection for local recurrence and the prognosis is generally poor. We report on a 32-year-old man with malignant fibrous histiocytoma of the kidney who remained free of recurrence for 1 year after radical nephrectomy.