Differences in Chemical Constituents between Dalbergia oliveri Heartwood and Sapwood and Their Effect on Wood Color

The purpose of this study was to characterize and quantify the chemical constituents of heartwood and sapwood of Dalbergia oliveri extract in order to investigate the chemical components that determine the formation of heartwood’s color. In this work, the types of pigments in heartwood and sapwood extract were analyzed using UV-Visible (UV) Spectrophotometer, and the main pigment components of heartwood and sapwood extract were identified and quantified using ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS). The results showed that the difference in content of the main components between heartwood and sapwood of Dalbergia oliveri was slight, and the lignin structure between heartwood and sapwood is basically identical; flavonoid pigments were found to be the primary chromophoric components of heartwood and sapwood extract. However, a total of 21 flavonoids were identified in heartwood and sapwood, of which the unique substances to heartwood were vitexin, isorhamnetin, and pelargonidin, and the content of isoliquiritigenin, formononetin, and biochanin A were 253, 37, and 583 times higher in the heartwood than in the sapwood, respectively, which could be the main pigment components affecting the significant color difference between heartwood and sapwood of Dalbergia oliveri. These results will provide a foundation for revealing the underlying mechanism of color difference between heartwood and sapwood and provide a theoretical basis for wood coloring

Chemical Composition of Dalbergia tonkinensis Heartwood Extracts and Comparison with Dalbergia odorifera

Dalbergia tonkinensis is very similar to Dalbergia odorifera in material, texture, and other macroscopic characteristics, and a comparison of the commonalities and differences in the chemical composition of the extractives may help to distinguish the two. However, the chemical composition of Dalbergia tonkinensis heartwood is unknown. The total flavonoid content of Dalbergia tonkinensis heartwood was determined to range between 49.67 to 101.95 mg, which indicated that Dalbergia tonkinensis is as equally rich in flavonoids as Dalbergia odorifera. Thirty-one flavonoids were identified via ultra-performance liquid chromatography-mass spectrometry in Dalbergia tonkinensis. Among them, the contents of 15 medicinal active flavonoids with were determined, and the liquiritigenin, naringenin, formononetin, pinocembrin, and biochanin A contents were found to be high. The 12 volatile compositions of Dalbergia tonkinensis heartwood identified via gas chromatography-mass spectrometry were very similar to those of Dalbergia odorifera and were dominated by trans-nerolidol, caryophyllene oxide, and eudesmol. The relationship between the chemical composition of Dalbergia tonkinensis and Dalbergia odorifera heartwood extracts was determined via a principal component analysis, and the results indicated that there was no significant difference in chemical composition between the two. This suggested that Dalbergia tonkinensis could be used as a potential substitute for Dalbergia odorifera

Chemical Composition of Dalbergia tonkinensis Heartwood Extracts and Comparison with Dalbergia odorifera

Dalbergia tonkinensis is very similar to Dalbergia odorifera in material, texture, and other macroscopic characteristics, and a comparison of the commonalities and differences in the chemical composition of the extractives may help to distinguish the two. However, the chemical composition of Dalbergia tonkinensis heartwood is unknown. The total flavonoid content of Dalbergia tonkinensis heartwood was determined to range between 49.67 to 101.95 mg, which indicated that Dalbergia tonkinensis is as equally rich in flavonoids as Dalbergia odorifera. Thirty-one flavonoids were identified via ultra-performance liquid chromatography-mass spectrometry in Dalbergia tonkinensis. Among them, the contents of 15 medicinal active flavonoids with were determined, and the liquiritigenin, naringenin, formononetin, pinocembrin, and biochanin A contents were found to be high. The 12 volatile compositions of Dalbergia tonkinensis heartwood identified via gas chromatography-mass spectrometry were very similar to those of Dalbergia odorifera and were dominated by trans-nerolidol, caryophyllene oxide, and eudesmol. The relationship between the chemical composition of Dalbergia tonkinensis and Dalbergia odorifera heartwood extracts was determined via a principal component analysis, and the results indicated that there was no significant difference in chemical composition between the two. This suggested that Dalbergia tonkinensis could be used as a potential substitute for Dalbergia odorifera

Adsorption Property, Kinetic and Equilibrium Studies of Activated Carbon Fiber Prepared from Liquefied Wood by Zncl₂ Activation

Activated carbon fiber was prepared from liquefied wood by chemical activation with ZnCl2 (Z-LWACF) at different impregnation ratios, with a particular focus on its adsorption property, kinetic and isotherm. The characterization and properties of Z-LWACFs were investigated by nitrogen adsorption/desorption, X-ray photoelectron spectroscopy (XPS), methylene blue (MB) and iodine adsorption. Two activation process methods were employed to prepare Z-LWACF and contrasted with others fibers. The results showed that the Z-LWACF obtained by one-step ZnCl2 activation present higher yields and specific surface area than others fibers. Besides, the change of MB adsorption value at different impregnation ratios was consistent with pore structure distribution above 1.5 nm pore size, indicating that larger micropores (1.5 to 2 nm) and mesopores played a major role in the MB adsorption by Z-LWACF. The kinetics of MB adsorption process was found to follow the pseudo-second-order kinetic model and the adsorption rate was controlled by chemisorption. It was also found that MB adsroption by Z-LWACF belonged to monolayer adsorption and Z-LWACF was easy to adsorb MB

Variation of Chemical Components in Sapwood, Transition Zone, and Heartwood of Dalbergia odorifera and Its Relationship with Heartwood Formation

Heartwood has a high economic value because of its natural durability, beautiful color, special aroma, and richness in active ingredients used in traditional Chinese medicine. However, the mechanism of heartwood formation remains unclear. Dalbergia odorifera was selected as the object of research to analyze this variation in the chemical composition of sapwood, transition zone, and heartwood as well as to elucidate the relationship between this variation and the formation of heartwood. The variation of secondary metabolites was analyzed using gas chromatography-mass spectrometry and ultra-high performance liquid chromatography–mass spectrometry, the variation of lignin was analyzed using Fourier transform infrared spectroscopy and ultraviolet visible spectrophotometry, and the variation law of mineral elements was analyzed using atomic absorption spectrophotometry. The results demonstrated that contents of characteristic secondary metabolites in Dalbergia odorifera were mainly distributed in heartwood (84.3–96.8%), increased from the outer to inner layers of the xylem, and sudden changes occurred in the transition zone (the fourth growth ring). The Dalbergia odorifera lignin can be identified as typical “syringyl–guaiacyl (S–G)” lignin, and the color darkened from the outside to the inside. The results demonstrated that there were more benzene rings and conjugated C=O structures in the heartwood. Additionally, the variation of minerals in the xylem was related to elemental types; the average concentrations of Mg, Ca, Fe and Sr were higher in the heartwood than in the sapwood, whereas the concentrations of K and Zn were higher in the sapwood than in the heartwood owing to the reabsorption of elements. The concentrations of Na and Cu were similar in the heartwood and sapwood. The composition and structural characteristics of secondary metabolites, lignin, and mineral elements in the three typical xylem regions (sapwood, transition zone and heartwood) of Dalbergia odorifera changed. The most abrupt change occurred in the narrow xylem transition zone, which is the key location involved in heartwood formation in Dalbergia odorifera