Antioxidant, Antimicrobial, and Anti-Inflammatory Effects of Liriodendron chinense Leaves.

Liriodendron chinense has been widely utilized in traditional Chinese medicine to treat dispelling wind and dampness and used for alleviating cough and diminishing inflammation. However, the antioxidant, antimicrobial, and anti-inflammatory effects of L. chinense leaves and the key active constituents remained elusive. So, we conducted some experiments to support the application of L. chinense in traditional Chinese medicine by investigating the antioxidant, antibacterial, and anti-inflammatory abilities, and to identify the potential key constituents responsible for the activities. The ethanol extract of L. chinense leaves (LCLE) was isolated and extracted, and assays measuring ferric reducing antioxidant power, total reducing power, DPPH•, ABTS•+, and •OH were used to assess its in vitro antioxidant capacities. Antimicrobial activities of LCLE were investigated by minimal inhibitory levels, minimum antibacterial concentrations, disc diffusion test, and scanning electron microscope examination. Further, in vivo experiments including macro indicators examination, histopathological examination, and biochemical parameters measurement were conducted to investigate the effects of LCLE on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. LCLE was further isolated and purified through column chromatography, and LPS-induced RAW264.7 cells were constructed to assess the diminished inflammation potential of the identified chemical composites. ABTS•+ and •OH radicals were extensively neutralized by the LCLE treatment. LCLE administration also presented broad-spectrum antimicrobial properties, especially against Staphylococcus epidermidis by disrupting cell walls. LPS-induced ALI in mice was significantly ameliorated by LCLE intervention, as evidenced by the histological changes in the lung and liver tissues as well as the reductions of nitric oxide (NO), TNF-α, and IL-6 production. Furthermore, three novel compounds including fragransin B2, liriodendritol, and rhamnocitrin were isolated, purified, and identified from LCLE. These three compounds exhibited differential regulation on NO accumulation and IL-10, IL-1ß, IL-6, TNF-α, COX-2, and iNOS mRNA expression in RAW264.7 cells induced by LPS. Fragransin B2 was more effective in inhibiting TNF-α mRNA expression, while rhamnocitrin was more powerful in inhibiting IL-6 mRNA expression. LCLE had significant antioxidant, antimicrobial, and anti-inflammatory effects. Fragransin B2, liriodendritol, and rhamnocitrin were probably key active constituents of LCLE, which might act synergistically to treat inflammatory-related disorders. This study provided a valuable view of the healing potential of L. chinense leaves in curing inflammatory diseases.

Can leaf drought tolerance predict species abundance and its changes in tropical-subtropical forests?

Climate change has resulted in an increase in drought severity in the species-rich tropical and subtropical forests of southern China. Exploring the spatiotemporal relationship between drought-tolerance trait and tree abundance provides a means to elucidate the impact of droughts on community assembly and dynamics. In this study, we measured the leaf turgor loss point (πtlp) for 399 tree species from three tropical forest plots and three subtropical forest plots. The plot area was 1 ha and tree abundance was calculated as total basal area per hectare according to the nearest community census data. The first aim of this study was to explore πtlp abundance relationships in the six plots across a range of precipitation seasonality. Additionally, three of the six plots (two tropical forests and one subtropical forest) had consecutive community censuses data (12-22 years) and the mortality ratios and abundance year slope of tree species were analyzed. The second aim was to examine whether πtlp is a predictor of tree mortality and abundance changes. Our results showed that tree species with lower (more negative) πtlp were more abundant in the tropical forests with relative high seasonality. However, πtlp was not related to tree abundance in the subtropical forests with low seasonality. Moreover, πtlp was not a good predictor of tree mortality and abundance changes in both humid and dry forests. This study reveals the restricted role of πtlp in predicting the response of forests to increasing droughts under climate change.

Tree growth is correlated with hydraulic efficiency and safety across 22 tree species in a subtropical karst forest.

Karst forests are habitats in which access to soil water can be challenging for plants. Therefore, safe and efficient xylem water transport and large internal water storage may benefit tree growth. In this study, we selected 22 tree species from a primary subtropical karst forest in southern China and measured their xylem anatomical traits, saturated water content (SWC), hydraulic conductivity (Ks) and embolism resistance (P50). Additionally, we monitored growth of diameter at breast height (DBH) in 440 individual trees of various sizes over three consecutive years. Our objective was to analyze the relationships between xylem structure, hydraulic efficiency, safety, water storage and growth of karst tree species. The results showed significant differences in structure but not in hydraulic traits between deciduous and evergreen species. Larger vessel diameter, paratracheal parenchyma and higher SWC were correlated with higher Ks. Embolism resistance was not correlated with the studied anatomical traits, and no tradeoff with Ks was observed. In small trees (5-15 cm DBH), diameter growth rate (DGR) was independent of hydraulic traits. In large trees (>15 cm DBH), higher Ks and more negative P50 accounted for higher DGR. From lower to greater embolism resistance, the size-growth relationship shifted from growth deceleration to acceleration with increasing tree size in eight of the 22 species. Our study highlights the vital contributions of xylem hydraulic efficiency and safety to growth rate and dynamics in karst tree species; therefore, we strongly recommend their integration into trait-based forest dynamic models.

Co-ordination between leaf biomechanical resistance and hydraulic safety across 30 sub-tropical woody species.

BACKGROUND AND AIMS: Leaf biomechanical resistance protects leaves from biotic and abiotic damage. Previous studies have revealed that enhancing leaf biomechanical resistance is costly for plant species and leads to an increase in leaf drought tolerance. We thus predicted that there is a functional correlation between leaf hydraulic safety and biomechanical characteristics. METHODS: We measured leaf morphological and anatomical traits, pressure-volume parameters, maximum leaf hydraulic conductance (Kleaf-max), leaf water potential at 50 % loss of hydraulic conductance (P50leaf), leaf hydraulic safety margin (SMleaf), and leaf force to tear (Ft) and punch (Fp) of 30 co-occurring woody species in a sub-tropical evergreen broadleaved forest. Linear regression analysis was performed to examine the relationships between biomechanical resistance and other leaf hydraulic traits. KEY RESULTS: We found that higher Ft and Fp values were significantly associated with a lower (more negative) P50leaf and a larger SMleaf, thereby confirming the correlation between leaf biomechanical resistance and hydraulic safety. However, leaf biomechanical resistance showed no correlation with Kleaf-max, although it was significantly and negatively correlated with leaf outside-xylem hydraulic conductance. In addition, we also found that there was a significant correlation between biomechanical resistance and the modulus of elasticity by excluding an outlier. CONCLUSIONS: The findings of this study reveal leaf biomechanical-hydraulic safety correlation in sub-tropical woody species.

[Source Profiles of Industrial Emission-Based VOCs in Chengdu].

The volatile organic compound (VOC) emission characteristics of various production procedures were analyzed through GC-MS after the emissions of typical enterprises such as automobile manufacturing, petrochemical, and other industries had been sampled with SUMMA canisters. Each production procedure in the automobile manufacturing and petrochemical industries was considered. The results showed that each automobile manufacturing procedure had its own dominant species, and alkanes (32%) and aromatics (35%) were the main emission species of coating spraying. The emission characteristics of furniture manufacturing were highly correlated with the raw materials, and the VOC emission species were mainly composed of aromatics (50%) and oxygenated VOCs (OVOCs) (38%). As for the petrochemical industry, VOC concentrations in various process plant areas ranged from 49 µg·m-3 to 1387 µg·m-3. As the main products of the refining area were C5-C9 gasoline and benzene series, whereas comparatively more solvents were used in the chemical area, which would generate alkene products, VOC concentrations greatly differed in the various process plant areas. In terms of electronic manufacturing, OVOCs were the main emission species, accounting for more than 50% of total VOCs. Alkanes and OVOCs were the main contributors to VOC emissions in shoemaking, accounting for 52% and 36% on average, respectively, which was strongly related to the species of the used solvents. The VOC emission species of automobile manufacturing were quite different, predominantly including n-dodecane and 2-butanone. The emission species of furniture manufacturing mainly included styrene, ethyl acetate, m/p-xylene, etc., which are typical species of coatings and diluents. As for the differences in the emission species of process plant areas in the petrochemical industry, styrene was the main species in the refining area, 1,3-butadiene in the chemical area, C3-C5 alkanes in the storage area, and C6-C8 alkanes in the wastewater treatment area. The main emission species of electronic manufacturing were ethanol, acetone, and other aldehyde ketone species. The emission species of shoemaking enterprises are mainly C5 and C6 alkanes. According to the results of ozone formation potential (OFP), alkenes and aromatics were the main VOC emission species that contribute significantly to the OFP in the automobile manufacturing and petrochemical industries, with relatively high pollution source reaction activity. The results showed that the emission ratio (17%-96%) and OFP contributions of OVOCs were significant in various industries. Therefore, for VOC emission control, in addition to focusing on the control of aromatics and alkenes, attention should also be paid to OVOCs.

[Source Profiles of VOCs Associated with Typical Industrial Processes in Chengdu].

The characteristics of volatile organic compound (VOCs) species from various production procedures of wood-based panel production and other industrial processes in Chengdu were analyzed through gas chromatography-mass spectrometry (GC-MS) and other methods specified in national standards after the emissions of typical enterprises of wood-based panel production, pharmaceutical manufacturing, chemical production and other industrial processes in Chengdu had been sampled using sampling bottles and SUMMA canisters. Generally, the process of wood-based panel production includes glue making, glue mixing, sorting, and hot pressing, whereas the process of pharmaceutical manufacturing includes workshop production and wastewater treatment. The results showed that the main contribution species of VOCs in wood-based panel production and pharmaceutical manufacturing is oxygenated VOCs (OVOCs), accounting for more than 50% of the total VOCs emitted. The species from organized and unorganized emissions of formaldehyde manufacturing differed significantly. The main species of organized emissions was OVOCs, and that of unorganized emissions was halohydrocarbons. Emissions of VOCs from coating manufacturing were strongly correlated with the raw materials, and the corresponding emission species were composed mainly of aromatics and OVOCs. Except for glue mixing, the main species of VOCs in other process procedures of wood-based panel production was formaldehyde, with emission proportion of more than 50%. The primary species of VOCs in various processes of pharmaceutical manufacturing was ethanol; however 1,4-dioxane, ethyl acetate, and toluene were also important species. Moreover, the main VOCs from formaldehyde manufacturing were composed mainly of acetone and ethanol, and those of coating manufacturing were aromatic hydrocarbons such as p-xylene. The ozone formation potential was to characterize the reactivity of pollution sources in VOCs from wood-based panel production, pharmaceutical manufacturing, and chemical production. The results showed that the species of VOCs in different industries contributed similarly to the reactivity and that these species were mainly high-activity species such as formaldehyde, ethanol, and other OVOCs as well as some aromatic hydrocarbons. Therefore, supervision and regulation of enterprises of industrial processes is required with a focus on species with relatively large ozone formation potential. In addition, it is necessary to analyze the emission characteristics and chemical mechanism of various industries and to control O3 generation from the sources.