OBJECTIVE: The skin interacts strictly with the surrounding environment. Despite an efficient system of protection, its integrity is continuously assaulted by a massive group of external stresses. UV irradiations repr...OBJECTIVE: The skin interacts strictly with the surrounding environment. Despite an efficient system of protection, its integrity is continuously assaulted by a massive group of external stresses. UV irradiations represent one of the most harmful factors for the cutaneous tissue. Both UV-A and UV-B can induce deep modifications of the different layers of the skin, including a weakening of its barrier function properties, DNA damages and degradation of the extracellular matrix. The aim of this project was to assess the UV protection activity of two natural compounds, the birch sap from Betula alba and organic extract from Inonotus obliquus (chaga mushroom) used separately or in a complex. METHODS: The anti-oxidant (ROS and MDA quantification, catalase and SOD activity measurement), anti-inflammatory (IL-1β, IL-6, IL-8, IL-10, TNF-α and INF-γ dosages) and the DNA protection/repair activities (DNA lesion site analysis) of birch sap and chaga mushroom extracts tested separately or in a complex containing organic birch sap 5% and Inonotus obliquus extracts 2% were evaluated in vitro after exposure of cultured keratinocytes and fibroblasts or reconstructed epidermis to UV-A/UV-B irradiations. RESULTS: We observed that birch sap from Betula alba and extracts from Inonotus obliquus prevent the formation of ROS and decrease the oxidative stress induced under UV irradiations, suggesting a strong anti-oxidant activity. In addition, the tested products showed an immunomodulatory effect by reducing the quantity of pro-inflammatory cytokines upon UV irradiations. UV-induced DNA damages of keratinocytes were also reduced by birch sap and chaga mushroom extracts. CONCLUSION: Here, for the first time, we have shown the photo-protection activity of extracts obtained from Betula alba and Inonotus obliquus mushroom on skin cells exposed to UV-A and UV-B irradiations. Due to their anti-oxidant, anti-inflammatory and DNA protection/repair activities, the tested products represent promising candidates in the development of cosmetic products with anti-photo-aging activity.展开更多
Experiments were conducted to determine two pieces of information essential to identify practices necessary to ensure tapping trees for birch sap collection is both sustainable and profitable—the selection of the tim...Experiments were conducted to determine two pieces of information essential to identify practices necessary to ensure tapping trees for birch sap collection is both sustainable and profitable—the selection of the time to initiate tapping birch trees to obtain maximum yields, and the volume of nonconductive wood (NCW) associated with taphole wounds in birch trees. The yields obtained from various timing treatments varied between sapflow seasons, but indicate that using test tapholes to choose the appropriate time to initiate tapping is likely to result in optimum yields from birch trees. The volume of NCW associated with taphole wounds in birch trees was highly variable and generally quite large, averaging 220 times the volume of the taphole drilled, and requiring relatively high radial growth rates to maintain NCW at sustainable levels over the long-term. However, more conservative tapping practices, including reduced taphole depth and increased dropline length, as well as thinning and other stand management practices, can be used to reduce the minimum growth rates required. Producers can use this information to ensure that they use tapping practices that will result in sustainable outcomes and obtain the maximum possible sap yields from their trees.展开更多
文摘OBJECTIVE: The skin interacts strictly with the surrounding environment. Despite an efficient system of protection, its integrity is continuously assaulted by a massive group of external stresses. UV irradiations represent one of the most harmful factors for the cutaneous tissue. Both UV-A and UV-B can induce deep modifications of the different layers of the skin, including a weakening of its barrier function properties, DNA damages and degradation of the extracellular matrix. The aim of this project was to assess the UV protection activity of two natural compounds, the birch sap from Betula alba and organic extract from Inonotus obliquus (chaga mushroom) used separately or in a complex. METHODS: The anti-oxidant (ROS and MDA quantification, catalase and SOD activity measurement), anti-inflammatory (IL-1β, IL-6, IL-8, IL-10, TNF-α and INF-γ dosages) and the DNA protection/repair activities (DNA lesion site analysis) of birch sap and chaga mushroom extracts tested separately or in a complex containing organic birch sap 5% and Inonotus obliquus extracts 2% were evaluated in vitro after exposure of cultured keratinocytes and fibroblasts or reconstructed epidermis to UV-A/UV-B irradiations. RESULTS: We observed that birch sap from Betula alba and extracts from Inonotus obliquus prevent the formation of ROS and decrease the oxidative stress induced under UV irradiations, suggesting a strong anti-oxidant activity. In addition, the tested products showed an immunomodulatory effect by reducing the quantity of pro-inflammatory cytokines upon UV irradiations. UV-induced DNA damages of keratinocytes were also reduced by birch sap and chaga mushroom extracts. CONCLUSION: Here, for the first time, we have shown the photo-protection activity of extracts obtained from Betula alba and Inonotus obliquus mushroom on skin cells exposed to UV-A and UV-B irradiations. Due to their anti-oxidant, anti-inflammatory and DNA protection/repair activities, the tested products represent promising candidates in the development of cosmetic products with anti-photo-aging activity.
文摘Experiments were conducted to determine two pieces of information essential to identify practices necessary to ensure tapping trees for birch sap collection is both sustainable and profitable—the selection of the time to initiate tapping birch trees to obtain maximum yields, and the volume of nonconductive wood (NCW) associated with taphole wounds in birch trees. The yields obtained from various timing treatments varied between sapflow seasons, but indicate that using test tapholes to choose the appropriate time to initiate tapping is likely to result in optimum yields from birch trees. The volume of NCW associated with taphole wounds in birch trees was highly variable and generally quite large, averaging 220 times the volume of the taphole drilled, and requiring relatively high radial growth rates to maintain NCW at sustainable levels over the long-term. However, more conservative tapping practices, including reduced taphole depth and increased dropline length, as well as thinning and other stand management practices, can be used to reduce the minimum growth rates required. Producers can use this information to ensure that they use tapping practices that will result in sustainable outcomes and obtain the maximum possible sap yields from their trees.
