Structural characterization and antioxidant activity of water-soluble lignin-carbohydrate complexes (LCCs) isolated from wheat straw.

Lignin-carbohydrate complex (LCC) was proven to possess antioxidant activities. To understand structures and antioxidant activities of LCC, water-soluble LCC-stalk, LCC-sheath and LCC-leaf were isolated from ball-milled wheat straw stalk, sheath and leaf by successive dissolution in LiCl/DMSO solvent, water extraction and purification. LCCs were later structurally characterized by wet chemistry, chromatography and spectroscopy respectively. Their antioxidant activities were evaluated by ferric reducing antioxidant power (FRAP) and DPPH radical scavenging assays. The results showed that three LCCs were carbohydrate-rich (≈70%) and presented relatively narrow molecular weight distribution (PI < 2.0). The lignin moieties of LCCs were mainly connected with ß-O-4' structures, and phenyl glycoside and γ-ester linkages were main LCC linkages in LCCs. However, guaiacyl units were the predominant lignin units in LCC-stalk and LCC-sheath, while syringyl units were predominant in LCC-leaf. Intermolecular cross-linkages were mainly pCA-bridges in LCC-stalk and FA-bridges in LCC-sheath and LCC-leaf. Besides, LCC-sheath featured higher polysaccharide content exhibited higher molecular weight, fewer LCC linkages and better antioxidant activities (DPPH radical scavenging rate up to 74.91%) than both LCC-stalk (74.55%) and LCC-leaf (64.52%). This work helped to know LCCs in wheat straw well and inspire the application of LCC as potential antioxidants.

Distribution study of tryptanthrin in rat tissues by HPLC and its relationship with meridian tropism of indigo naturalis in traditional Chinese medicine.

The aim of the present study is to characterize the distribution of tryptanthrin (TRYP) in rat tissues following oral administration at a dose of 100 mg/kg and its relationship with meridian tropism (MT) of indigo naturalis (IN) in traditional Chinese medicine (TCM). For quantitative analysis in biological samples, a sensitive, inexpensive and accurate high-performance liquid chromatographic method was developed and validated with 2-hydroxy acetophenone as internal standard, a Shimadzu C18 column and water-acetonitrile (55:45, v/v) as mobile phase. Acceptable intra-day and inter-day precision at high, medium and low concentration was acquired with RSD ranging from 0.87 to 5.22% and from 1.25 to 6.47%, respectively. Good assay and extraction recoveries were obtained with a single and relatively fast step to precipitate protein. The extraction recovery of TRYP ranged from 87.5 to 94.5 %. TRYP concentration was highest in the liver and remained for a much longer time than in other tissues. It could also be detected in kidney, lung, heart and spleen, but not in brain under the experimental conditions. The results confirmed the traditional knowledge of TCM that MT of IN belongs to the liver meridians and demonstrated that TRYP is one of the active constituents of the MT of IN.

[Study on the chemical changes of whole constituents in the preparing process of kansui root].

OBJECTIVE: To study the chemical changes of whole constituents in the preparing process of kansui root in order to uncover the mechanism of detoxication in preparing process. METHODS: The raw and prepared kansui were extracted with water and methanol and analyzed with HPLC respectively. RESULTS: Seven constituents disappeared in the prepared kansui and four new consitituents were produced in the water extracts. The concentration of four other constituents decreased. In the methoanol extract, two constituents disappeared and one constituent produced during preparing process. The concentration of six other constituents increased in the methanol extracts. CONCLUSION: The mechanism of detoxication of kansui root preparing process is may be that the toxic constituents decomposing or water solubility reducing.