Min-Jay Chung

Phytochemicals from Cunninghamia konishii Hayata Act as Antifungal Agents

The aims of the present study were to isolate and identify the antifungal compounds from the ethanolic extract of Cunninghamia konishii wood and to evaluate their antifungal activities against wood decay fungi. The results showed that the n-Hex soluble fraction of the ethanolic extract from C. konishii wood had an excellent inhibitory effect against Lenzites betulina, Trametes versicolor, Laetiporus sulphureus, and Gloeophyllum trabeum, with IC(50) values of 33, 46, 62, and 49 μg/mL, respectively. By following the bioactivity-guided fractionation procedure, four sesquiterpenes, T-cadinol, cedrol, T-muurolol, and (-)-epi-cedrol, and three diterpenes, 13-epi-manool, cis-abienol, and isoabienol, were identified from the active subfractions. Among the main constituents of the ethanolic extract from C. konishii, T-cadinol, cedrol, and T-muurolol efficiently inhibited the growth of four wood-rot fungi at the concentration of 100 μg/mL, with antifungal indices of 51.4-100.0%, 68.3-100.0%, and 39.5-100.0%, respectively. Results of this study show that the ethanolic extract of C. konishii wood may be considered as a potent source of T-cadinol, cedrol, and T-muurolol as new natural antifungal agents.

Profiling of volatile compounds of Phyllostachys pubescens shoots in Taiwan.

This study examined the influence of heating temperature and duration on volatile aromatic components of spring and winter Phyllostachys pubescens shoots using SPME. Results from GC-MS analyses revealed that the main constituents in both bamboo shoots at ambient temperature include methoxy-phenyl oxime, followed by n-hexanol and 3Z-hexenal, which gives a fresh green aroma. Comparing the different compounds, between spring and winter shoots, revealed that spring bamboo shoots at ambient temperature comprise 12.30% methyl salicylate, which provides protection against insect attack, and 9.71% epi-cedrol; while winter bamboo shoots comprise 17.00% 1-octen-3-ol, which produces a distinct mushroom aroma. After heating at 100 °C for 60 min, a marked increase in relative content of benzyl salicylate (43.30%) and a significant decrease in methyl salicylate content in spring bamboo shoots were observed; while the major compound in winter bamboo shoots was n-heneicosane (78.09%) and the content of specific 1-octen-3-ol significantly decreased.

Chemical Composition and Antitermitic Activity against Coptotermes formosanusShiraki of Cryptomeria japonica Leaf Essential Oil

Cryptomeria japonica D. Don, called ‘sugi’ in Japanese, is an abundant and renewable potential resource of valuable natural products that may serve as natural biocides in Taiwan. Hydrodistillation (HD) and steam distillation (SD) were used for extracting the essential oils from C. japonica leaves in this study. The chemical constituents of the two leaf essential oils were identified by GC/MS analysis, and their antitermitic activities were evaluated. The results from the antitermitic tests against Coptotermes formosanus Shiraki showed that the leaf essential oils extracted by HD and SD had excellent antitermitic activities, with LD50 values of 1.57 and 1.72 mg/g after 7 d of testing, respectively. Comparison of the chemical composition of the two leaf essential oils revealed that oxygenated diterpenes (kaur‐16‐ene) and oxygenated sesquiterpenes (β‐elemol) were the dominant constituents. In addition, 13 constituents isolated from the C. japonica leaf essential oils were tested individually against C. formosanus. Among these constituents, β‐elemol and α‐terpineol achieved 100% termite mortality at the dosage of 1 mg/g after 7 d of testing. These results demonstrated that both C. japonica leaf essential oils as well as β‐elemol and α‐terpineol possessed commendable antitermitic activity.

Green color protection of bamboo culms using one-step alkali pretreatment-free process

This study evaluated the protection effectiveness of alcohol-borne reagents for the green color of ma bamboo (Dendrocalamus latiflorus Munro) and moso bamboo (Phyllostachys pubescens Mazel). The results show that the types and concentrations of alcohol-borne reagents, the kinds of solvent, and the conditions of treatment greatly affected the green color of these two bamboo species. Without alkali pretreatment, an excellent green color protection (a* = −14.5) was obtained when the ma bamboo culms were treated with 0.5% methanol-borne copper chloride (CuCl2) at 60°C for 30 min. Similar results were also obtained when ma bamboo culms were treated with 0.5% methanol-borne copper nitrate [Cu(NO3)2] at 60°C for 2 h (a* = −13.5). For moso bamboo, an attractive green color in the bamboo culms was achieved by treating the specimens with 1% methanol-borne copper acetate [Cu(CH3COO)2] at 60°C for 30 min. The a* value of treated specimens was −13.3. In addition, results demonstrated that ultrasonic treatment was more effective on green color protection than conventional water bath treatment. When moso bamboo was treated with 1% copper acetate at 60°C in an ultrasonic bath for only 15 min, a remarkable green color with an a* value of −13.6 was obtained on the bamboo epidermis.

Insecticidal activities of Cunninghamia konishii Hayata against Formosan subterranean termite, Coptotermes formosanus (Isoptera: Rhinotermitidae).

BACKGROUND Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), is a major urban pests in many countries throughout the world. In an attempt to find natural products that could be employed in the effective and environmentally friendly control of the termite, this study investigates, for the first time, the insecticidal activities of the wood and leaf essential oils and ethanolic extracts from Cunninghamia konishii Hayata against C. formosanus according to direct contact application. RESULTS Wood and leaf essential oils and wood ethanolic extract showed the excellent antitermitic activities. Among the four fractions of wood ethanolic extract, the hexane-soluble fraction showed the strongest antitermitic activities. In addition, β-elemol and α-cadinol showed excellent inhibitory action against C. formosanus. CONCLUSION The results clearly reveal that the wood and leaf essential oils and ethanolic extract from C. konishii, and their effective constituents, served as potential, eco-friendly termite-control agents.

Antipathogenic Activities and Chemical Composition of Cinnamomum osmophloeum and Cinnamomum zeylanicum Leaf Essential Oils

Abstract In this study, inhibitory activities of leaf essential oils from Cinnamomum osmophloeum and Cinnamomum zeylanicum and their major constituents (trans-cinnamaldehyde and eugenol) against Rhizoctonia solani were investigated. Furthermore, the relationship between the antipathogenic activity and the chemical structure of trans-cinnamaldehyde and eugenol is discussed. Results demonstrated that leaf essential oils and their major constituents from C. osmophloeum and C. zeylanicum had strong antipathogenic activities against R. solani. Results obtained from the chemical structure–antipathogenic activity relationship study suggested that trans-cinnamaldehyde or (E)-cinnamic acid with an aldehyde (‒CHO) or an acid (‒COOH) group, a conjugated double bond, and a Length of CH chain outside the ring affect their antipathogenic activity. Furthermore, the presence of the methyl moiety in the ortho position may have a considerable influence on the inhibitory action against R. solani. In addition, compounds with a free phenolic hydroxyl (‒OH) group and a double bond at the C7 position of the phenylpropenes also exhibited potent antipathogenic activity.

Environmentally benign methods for producing green culms of ma bamboo (Dendrocalamus latiflorus) and moso bamboo (Phyllostachys pubescens)

The objective of this study was to find an effective method for treating ma bamboo (Dendrocalamus latiflorus) and moso bamboo (Phyllostachys pubescens) using new water-based reagents containing copper. The effects of green-color protection using various treatments on bamboo culms were examined in this study. Two methods were used: heating in a water bath and ultrasonic dipping. The results revealed that excellent green-color protection (a* value of −6.2) was obtained when ma bamboo culms were treated with 0.25% ammoniacal copper quaternary compound-type B (ACQ-B) in a water bath at 100°C for 2 h. It was also found that the wettability of bamboo epidermis increasedsignificantly after pretreatment in a mixture of 1% KOH and surfactant in a water bath at 100°C for 30 min. Furthermore, pretreated moso bamboo culms exhibited excellent green-color protection after they were treated with 0.25% ACQ-B at 100°C for 2 h (a* value of −8.2). This novel treatment method definitely endows the bamboo culms with a fascinating green skin color and consequently could increase the economic value of bamboo products. No improvement in green-color protection was found when ultrasonic energy was added to the water bath at ambient temperature.

Chemical Polymorphism and Composition of Leaf Essential Oils of Cinnamomum kanehirae Using Gas Chromatography/Mass Spectrometry, Cluster Analysis, and Principal Component Analysis

Cinnamomum kanehirae Hayata is an endemic tree species in Taiwan. Leaf essential oils from 26 sources of C. kanehirae were obtained by hydrodistillation and their chemical constituents were analyzed by gas chromatography-mass spectrometry (GC-MS). Fifty-eight compounds were identified from C. kanehirae leaf essential oils. The main constituents in leaf essential oils were linalool, 1,8-cineole, β-selinene, 1-hexadecyne, and α-cadinol. According to the chemical compositions of leaf essential oils and their relative contents obtained from GC-MS analyses, cluster analysis, and principal component analysis, the 26 sources examined were classified into five chemotypes: linalool type, linalool/1,8-cineole type, 1,8-cineole type, linalool/α-cadinol type, and mixed type. The biochemical correlations between the major constituents of C. kanehirae were examined and their relationship is discussed.