Protective effect of Helianthus annuus seed byproduct extract on ultraviolet radiation-induced injury in skin cells.

Helianthus annuus seed byproduct is a residual product obtained after seed oil extraction. The present study investigated the preventive and repair effects of the H. annuus seed byproduct ethanol extract (HSE) on ultraviolet radiation (UVR)-induced injury in human immortalized keratinocytes (HaCaTs) and human skin fibroblasts (HSFs). Results revealed that the total phenolic acid and oligosaccharide content in HSE was >50%. HSE had a stronger preventive effect on UVR-induced injury than the repair effect. Moreover, phenolic acids were the main active component of HSE mediating the preventative effect. In HaCaTs and HSFs, HSE prevented UVR-induced injury by inhibiting excessive ROS production. It reduced the secretion of tumor necrosis TNF-α, IL-1α, IL-1ß, IL-6, and IL-8 by inhibiting the level of ROS, thus reducing inflammation-mediated injury to skin cells. In addition, HSE inhibited the expression of various mRNA kinases in the MAPK-ERK/p38/JNK pathway. This downregulated the expression of activator protein-1 (AP-1) mRNA and further reduced the secretion of matrix metalloproteinase (MMP)-1, MMP-3, and MMP-9 as well as reduced UVR-induced injury to the cells. In conclusion, HSE is a broad-spectrum, natural UV filter with high efficiency and low toxicity that has the potential to be used in sunscreen products.

Effects of 5-HT on the cold resistance of mangrove Kandelia obovata seedlings.

5-hydroxytryptamine (5-HT) participates in plant growth and development, and can also delay senescence and cope with abiotic stress. To explore the role of 5-HT in regulating the abilities of mangrove in cold resis-tance, we examined the effects of cold acclimation and the spraying of p-chlorophenylalanine (p-CPA, 5-HT synthesis inhibitor) on leaf gas exchange parameters and CO2 response curves (A/Ca), as well as the endogenous phytohormone content levels in the mangrove species Kandelia obovata seedlings under low temperature stress. The results showed that low temperature stress significantly reduced the contents of 5-HT, chlorophyll, endogenous auxin (IAA), gibberellin (GA), and abscisic acid (ABA). It weakened the CO2 utilization abilities of plants and reduced net photosynthetic rate, which ultimately reduced carboxylation efficiency (CE). Under low temperature stress, exogenous p-CPA reduced the contents of photosynthetic pigments, endogenous hormones, and 5-HT in the leaves, which aggravated the damages caused by low temperature stress on photosynthesis. By enhancing cold acclimation abilities, the endogenous IAA content in the leaves could was reduced under low temperature stress, promoted the production of 5-HT, improved the contents of photosynthetic pigments, GA, and ABA, as well as enhanced photosynthetic carbon assimilation abilities, which would increase photosynthesis in the K. obovata seedlings. Under cold acclimation conditions, the spraying of p-CPA could significantly inhibit the synthesis of 5-HT, promote the production of IAA, and reduce the contents of photosynthetic pigments, GA, ABA, and CE, which would weaken the effects of cold acclimation by improving the cold resistance of mangroves. In conclusion, cold acclimation could improve the cold resistance abilities of K. obovata seedlings by regulating photosynthetic carbon assimilation capacity and the contents of endogenous phytohormone. 5-HT synthesis is one of the necessary conditions for improving the cold resistance abilities of mangroves.

Submergence Tolerance and Germination Dynamics of Roegneria nutans Seeds in Water-Level Fluctuation Zones with Different Water Rhythms in the Three Gorges Reservoir.

The Three Gorges Dam features two water-level fluctuation zones (WLFZs): the preupland drawdown zone (PU-DZ) and the preriparian drawdown zone (PR-DZ). To investigate the vegetation potential of Roegneria nutans in WLFZs, we compared the submergence tolerance and germination dynamics in the natural riparian zone (NRZ), PU-DZ and PR-DZ. We found that the NRZ seeds maintained an 81.3% intactness rate and >91% germination rate. The final seed germination rate and germination dynamics were consistent with those of the controls. Meanwhile, the PU-DZ seeds submerged at 5 m, 10 m, 15 m, and 20 m exhibited intactness rates of 70.5%, 79.95%, 40.75%, and 39.87%, respectively, and >75% germination. Furthermore, the PR-DZ seeds exhibited intactness rates of 22.44%, 61.13%, 81.87%, and 15.36% at 5 m, 10 m, 15 m, and 17 m, respectively, and 80% germination. The germination rates of the intact seeds submerged >10 m were >80%. Finally, the intact seeds germinated quickly in all WLFZs. The high proportion of intact seeds, rapid germination capacity, and high germination rate permit R. nutans seeds to adapt to the complicated water rhythms of the PU-DZ and PR-DZ and indicate the potential for their use in vegetation restoration and recovery. Thus, perennial seeds can be used for vegetation restoration in the WLFZs of large reservoirs and in other regions with water rhythms similar to the Three Gorges Reservoir.

[Drug permeability through buccal mucosa].

OBJECTIVE: To investigate the effects of physicochemical properties of drug on its permeability through buccal mucosa. METHODS: Benzoic acid, caffeine and hydrocortisone were selected as model drugs and their permeability coefficients through isolated porcine buccal mucosa were determined. RESULT: The permeability coefficients of benzoic acid, caffeine and hydrocortisone through isolated porcine buccal mucosa were (1.01 x 10(-4)+/-1.64 x 10(-5))cm.s(-1)ì(2.75 x 10(-5)+/-1.79 x 10(-6))cm.s(-1) and (2.49 x 10(-5)+/-6.32 x 10(-6))cm.s(-1), which were 14,989 and 389 times as those through human skin, respectively. CONCLUSION: The permeability of drugs through buccal mucosa seems to be much better than that through human skin.