Fu-Lan Hsu

In Vivo Antioxidant Activities of Essential Oils and Their Constituents from Leaves of the Taiwanese Cinnamomum osmophloeum

Cinnamomum osmophloeum Kaneh is an indigenous tree species in Taiwan. In this study, phytochemical characteristics and antioxidant activities of the essential oils and key constituents from the leaves of two C. osmophloeum clones were investigated. The two trees possess two chemotypes, which were classified as the cinnamaldehyde type and camphor type. We demonstrated that the essential oils from C. osmophloeum leaves exerted in vivo antioxidant activities in Caenorhabditis elegans. In addition, trans-cinnamaldehyde and D-(+)-camphor, which respectively represent the major compounds in the cinnamaldehyde-type and camphor-type trees, exerted significant in vivo antioxidant activities against juglone-induced oxidative stress in C. elegans. Moreover, expressions of antioxidative-related genes, including superoxide dismutase (SOD) and glutathione S-transferase (GST), were significantly induced by trans-cinnamaldehyde and D-(+)-camphor from C. osmophloeum leaves. Our results showed that the essential oils from C. osmophloeum leaves and their major compounds might have good potential for further development as nutraceuticals or antioxidant remedies.

Removal of arsenic from groundwater by using a native isolated arsenite-oxidizing bacterium ☆

Arsenic (As) contamination of groundwater is a significant public health concern. In this study, the removal of arsenic from groundwater using biological processes was investigated. The efficiency of arsenite (As(III)) bacterial oxidation and subsequent arsenate (As(V)) removal from contaminated groundwater using bacterial biomass was examined. A novel As(III)-oxidizing bacterium (As7325) was isolated from the aquifer in the blackfoot disease (BFD) endemic area in Taiwan. As7325 oxidized 2300μg/l As(III) using in situ As(III)-contaminated groundwater under aerobic conditions within 1d. After the oxidation of As(III) to As(V), As(V) removal was further examined using As7325 cell pellets. The results showed that As(V) could be adsorbed efficiently by lyophilized As7325 cell pellets, the efficiency of which was related to lyophilized cell pellet concentration. Our study conducted the examination of an alternative technology for the removal of As(III) and As(V) from groundwater, indicating that the oxidation of As(III)-contaminated groundwater by native isolated bacterium, followed by As(V) removal using bacterial biomass is a potentially effective technology for the treatment of As(III)-contaminated groundwater.

The ameliorative and toxic effects of selenite on Caenorhabditis elegans.

Selenium is an essential trace nutrient that has a narrow exposure window between its beneficial and detrimental effects. We investigated how selenium affected the development, fertility, and cholinergic signaling of the nematode, Caenorhabditis elegans. Our results showed that selenite supplementation at 0.01 and 0.05 μM accelerated development and increased the brood size, while the addition of 20 μM selenite retarded the developmental rate and decreased the brood size. We also showed that the 0.01 μM selenite-pretreated nematodes were more resistant to paralysis induced by an acetylcholinesterase inhibitor, aldicarb, and a nicotinic acetylcholine receptor agonist, levamisole, compared to untreated worms. In contrast, 20 μM selenite-pretreated animals were more sensitive to aldicarb- and levamisole-induced paralysis compared to untreated worms. We measured the internal selenium in supplemented worms using inductively coupled plasma atomic emission spectroscopy, and the data obtained suggested that selenite added to growth medium was taken up by the worms. Taken together, these results suggest that selenite exerts both ameliorative and toxic effects on C.elegans, depending on the amount. Our investigations here thus reinforce our understanding of the ameliorative and toxic effects of selenium on development, reproduction, and cholinergic signaling.

Antioxidant Activity, Delayed Aging, and Reduced Amyloid-β Toxicity of Methanol Extracts of Tea Seed Pomace from Camellia tenuifolia

There is a growing interest in the exploitation of the residues generated by plants. This study explored the potential beneficial health effects from the main biowaste, tea seed pomace, produced when tea seed is processed. DPPH radical scavenging and total phenolic content assays were performed to evaluate the in vitro activities of the extracts. Caenorhabditis elegans was used as in vivo model to evaluate the beneficial health effects, including antioxidant activity, delayed aging, and reduced amyloid-β toxicity. Among all soluble fractions obtained from the extracts of tea seed pomace from Camellia tenuifolia, the methanol (MeOH)-soluble fraction has the best in vivo antioxidant activities. The MeOH-soluble extraction was further divided into six fractions by chromatography with a Diaion HP-20 column eluted with water/MeOH, and fraction 3 showed the best in vitro and in vivo antioxidant activities. Further analysis in C. elegans showed that the MeOH extract (fraction 3) of tea seed pomace significantly decreased intracellular reactive oxygen species, prolonged C. elegans lifespan, and reduced amyloid-β (Aβ) toxicity in transgenic C. elegans expressing human Aβ. Moreover, bioactivity-guided fractionation yielded two potent constituents from fraction 3 of the MeOH extract, namely, kaempferol 3-O-(2″-glucopyranosyl)-rutinoside and kaempferol 3-O-(2″-xylopyranosyl)-rutinoside, and both compounds exhibited excellent in vivo antioxidant activity. Taken together, MeOH extracts of tea seed pomace from C. tenuifolia have multiple beneficial health effects, suggesting that biowaste might be valuable to be explored for further development as nutraceutical products. Furthermore, the reuse of agricultural byproduct tea seed pomace also fulfills the environmental perspective.

Essential Oil Alloaromadendrene from Mixed-Type Cinnamomum osmophloeum Leaves Prolongs the Lifespan in Caenorhabditis elegans

Cinnamomum osmophloeum Kaneh. is an indigenous tree species in Taiwan. The present study investigates phytochemical characteristics, antioxidant activities, and longevity of the essential oils from the leaves of the mixed-type C. osmophloeum tree. We demonstrate that the essential oils from leaves of mixed-type C. osmophloeum exerted in vivo antioxidant activities on Caenorhabditis elegans. In addition, minor (alloaromadendrene, 5.0%) but not major chemical components from the leaves of mixed-type C. osmophloeum have a key role against juglone-induced oxidative stress in C. elegans. Additionally, alloaromadendrene not only acts protective against oxidative stress but also prolongs the lifespan of C. elegans. Moreover, mechanistic studies show that DAF-16 is required for alloaromadendrene-mediated oxidative stress resistance and longevity in C. elegans. The results in the present study indicate that the leaves of mixed-type C. osmophloeum and essential oil alloaromadendrene have the potential for use as a source for antioxidants or treatments to delay aging.

Effects of chemical modification reagents on acoustic properties of wood.

Summary The acoustic properties of several chemically modified Sitka spruce samples (Picea sitchensis Carr.) were evaluated in the longitudinal direction of wood specimens. Sitka spruce treated with glyoxal and carboxymethyl cellulose (CMC) displayed superior acoustic properties to those obtained by the other treatments. The acoustic converting efficiency (ACE) of the glyoxal-CMC treated Sitka spruce was 1.84 times of that of the untreated specimen and the specific dynamic Youngs modulus (E′/r) was retained without decrement after such treatment. Changes in the tanδ of Sitka spruce treated with glyoxal and different concentrations of 1,4-butanediol were opposite. With a low concentration of 1,4-butanediol (10%), the tanδ of the treated specimen decreased as a result of the formation of crosslinked cyclic structures. The potential presence of more alkyl hydroxyl groups in the Sitka spruce, after being treated with glyoxal and a high concentration of 1,4-butanediol (20%), resulted in the increment of tanδ and the decrement of ACE. The impairment of the acoustic properties of Sitka spruce was caused by the introduction of free chains with endwise carboxylic acid groups into cell walls after the succinic anhydride treatment. Slight improvement on the ACE of Sitka spruce was achieved by the reaction with acetic anhydride and the decrease in the tanδ was about 15%, which was attributed to the partial formation of crosslinked matrix. These results revealed the improvement of the acoustic properties of chemically modified wood that was probably achieved only by the formation of network structures between wood components and reagents.

Both Phosphorus Fertilizers and Indigenous Bacteria Enhance Arsenic Release into Groundwater in Arsenic-Contaminated Aquifers.

Arsenic (As) is a human carcinogen, and arsenic contamination in groundwater is a worldwide public health concern. Arsenic-affected areas are found in many places but are reported mostly in agricultural farmlands, yet the interaction of fertilizers, microorganisms, and arsenic mobilization in arsenic-contaminated aquifers remains uncharacterized. This study investigates the effects of fertilizers and bacteria on the mobilization of arsenic in two arsenic-contaminated aquifers. We performed microcosm experiments using arsenic-contaminated sediments and amended with inorganic nitrogenous or phosphorus fertilizers for 1 and 4 months under aerobic and anaerobic conditions. The results show that microcosms amended with 100 mg/L phosphorus fertilizers (dipotassium phosphate), but not nitrogenous fertilizers (ammonium sulfate), significantly increase aqueous As(III) release in arsenic-contaminated sediments under anaerobic condition. We also show that concentrations of iron, manganese, potassium, sodium, calcium, and magnesium are increased in the aqueous phase and that the addition of dipotassium phosphate causes a further increase in aqueous iron, potassium, and sodium, suggesting that multiple metal elements may take part in the arsenic release process. Furthermore, microbial analysis indicates that the dominant microbial phylum is shifted from α-proteobacteria to β- and γ-proteobacteria when the As(III) is increased and phosphate is added in the aquifer. Our results provide evidence that both phosphorus fertilizers and microorganisms can mediate the release of arsenic to groundwater in arsenic-contaminated sediments under anaerobic condition. Our study suggests that agricultural activity such as the use of fertilizers and monitoring phosphate concentration in groundwater should be taken into consideration for the management of arsenic in groundwater.

Failure mechanism of hollow tree trunks due to cross-sectional flattening

Failure of hollow trees in urban areas is a worldwide concern, and it can be caused by different mechanisms, i.e. bending stresses or flattening-related failures. Here we derive a new analytical expression for predicting the bending moment for tangential cracking, and compare the breaking moment of various failure modes, including Brazier buckling, tangential cracking, shear failure and conventional bending failure, as a function of t/R ratio, where t and R are the trunk wall thickness and trunk radius, respectively, of a hollow tree. We use Taiwan red cypress as an example and show that its failure modes and the corresponding t/R ratios are: Brazier buckling (Mode I), tangential cracking followed by longitudinal splitting (Mode II) and conventional bending failure (Mode III) for 0 < t/R < 0.06, 0.06 < t/R < 0.27 and 0.27 < t/R < 1, respectively. The exact values of those ratios may vary within and among species, but the variation is much smaller than individual mechanical properties. Also, shear failure, another type of cracking due to maximum shear stress near the neutral axis of the tree trunk, is unlikely to occur since it requires much larger bending moments. Hence, we conclude that tangential cracking due to cross-sectional flattening, followed by longitudinal splitting, is dominant for hollow trunks. Our equations are applicable to analyse straight hollow tree trunks and plant stems, but are not applicable to those with side openings or those with only heart decay. Our findings provide insights for those managing trees in urban situations and those managing for conservation of hollow-dependent fauna in both urban and rural settings.

Detection of Internal Holes in Swietenia mahagoni Disks Using a Stress Wave Device

The objectives of this study were to evaluate the feasibility of detecting different sizes and positions of hidden defects in trees using a 2-sensor stress wave device. In addition, we attempted to evaluate the detection resolution of the stress wave method which was rarely discussed previously. Artificial holes were created in Swietenia mahagoni disks to imitate natural decay in a trunk and were then detected using stress waves. The results revealed that as the diameter of the artificial hole increased, the radial transit time of the disk increased. This increasing tendency was repeated in the relationship between the radial relative transit time (RT) and the relative hole diameter (RD) and was discordant in the tangential direction. The tangential RT was greatly influenced by the position of the hole: it was highly related to the RD when the hole was near the 2 sensors; while it is not related to the RD when the hole was far from the 2 sensors. We also found that detection resolutions of stress waves, defined as the diameter or area ratio when the radial velocity had decreased by 10%, were 0.29 and 8.4%, respectively. A tree was considered to be decayed when the relative velocity (RV) was ＜ 0.9 and was considered hazardous when the RV was ＜ 0.66 with a central hole. On the basis of the results obtained, it appears that a 2-sensor stress wave device allows the nondestructive inspection of the presence, size, and location of defects in trees and could be a cost-effective way to perform tree risk assessments.