Effect of orally ingested diosgenin into diet on skin collagen content in a low collagen skin mouse model and its mechanism of action.

Aims: Influence on collagen content with oral ingestion of diosgenin (Dios) was investigated in established low collagen skin mouse model. And its mechanism of action was investigated using primary cultured fibroblasts.

Main Methods: Hairless mice were fed a low protein diet with Dios for 8weeks and the contents of collagen in skin were determined by measuring the content of hydroxyproline (Hyp).

Pharmacokinetics of Paradol Analogues Orally Administered to Rats.

The kinetics parameters of paradols with different acyl chain lengths have been evaluated to determine their antiobesity site of action. Rats were orally administered olive oil containing 0-, 6-, 8-, or 12-paradol, and blood samples were collected at different time points. The concentrations of the paradols in the plasma were analyzed both with and without β-glucuronidase treatment.

Relationship between the acyl chain length of paradol analogues and their antiobesity activity following oral ingestion.

6-Paradol is known to activate thermogenesis in brown adipose tissue (BAT), and paradol analogues with different acyl chain lengths possess different pungency thresholds. In this study, the influence of the acyl chain length on the antiobesity activity of the paradol analogues was investigated. The antiobesity activity of 6-paradol in mice fed a high-fat diet for 8 weeks was greater than that of dihydrocapsiate.

Novel effects of diosgenin on skin aging.

Extracts of Dioscorea coomposita or Dioscorea villosa are consumed as supplemental health foods at the time of climacteric. The extracts contain large amounts of the plant steroid, diosgenin. Here, we studied the safety and efficacy of diosgenin against skin aging at the time of climacteric.

Tight junction proteins in keratinocytes: localization and contribution to barrier function.

Recent research suggests that tight junctions (TJs) are located in the stratum granulosum, where they contribute to the barrier function of the epidermis. In this study, we investigated the formation of functional TJs in cultured normal human epidermal keratinocytes. We observed the development of permeability barrier function through the process of Ca(2+)-induced differentiation.

Changes in responses of UVB irradiated skin of brownish guinea pigs with aging.

It is known that skin often shows irregular pigmentation during aging, which is frequently associated with hyperpigmentation. Many studies have utilized brownish A1 guinea pigs to investigate the pathogenesis of ultraviolet B (UVB)-induced skin pigmentation, however, responses associated with aging following UVB irradiation have not been elucidated. To characterize those responses, dorsal skin of A1 guinea pigs from 14-weeks to 5-yr old were investigated.

Effect of ingested concentrate and components of sake on epidermal permeability barrier disruption by UVB irradiation.

Daily topical applications of the concentrate of sake (CS) have been shown to reduce epidermal barrier disruption in murine skin caused by ultraviolet B (UVB) radiation, while one of the components of sake, ethyl alpha-D-glucoside (alpha-EG), also reduces barrier disruption. We confirmed the effect of oral ingestion of various doses of CS on epidermal barrier disruption caused by UVB irradiation in hairless mice. Then, to identify the effective components, we quantitatively analyzed alpha-EG, organic acids, and glycerol, the main components of CS, and examined the effect of various concentration of each on barrier disruption.

Pigmentation in intrinsically aged skin of A1 guinea pigs.

It is known that skin often shows irregular pigmentation during aging which is frequently associated with hyperpigmentation. Many studies have utilized brownish A1 guinea pigs to investigate the pathogenesis of ultraviolet (UV)-induced skin pigmentation, however, changes associated with intrinsic aging in A1 guinea pig skin have not been documented. To characterize such changes, skin from the dorsal and neck areas of 20-week, 1-, 2-, 3- and 5-yr-old guinea pigs was examined.

Claudin-based tight junctions are crucial for the mammalian epidermal barrier: a lesson from claudin-1-deficient mice.

The tight junction (TJ) and its adhesion molecules, claudins, are responsible for the barrier function of simple epithelia, but TJs have not been thought to play an important role in the barrier function of mammalian stratified epithelia, including the epidermis. Here we generated claudin-1-deficient mice and found that the animals died within 1 d of birth with wrinkled skin. Dehydration assay and transepidermal water loss measurements revealed that in these mice the epidermal barrier was severely affected, although the layered organization of keratinocytes appeared to be normal.