Eight new bibenzyl derivatives from Dendrobium candidum.

Eight bibenzyl derivatives, namely dendrocandins J-Q (1-8), were isolated from the stems of Dendrobium candidum. Their structures were elucidated by 1D and 2D NMR experiments and mass spectrometry. Compounds 1-8 were examined for antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl free radical scavenging assay, and the IC50 values were 36.8, 70.2, 45.0, 60.5, 87.6, 50.4, 22.3, and 30.3 µM, respectively.

Stimulation of dragon's blood accumulation in Dracaena cambodiana via fungal inoculation.

Dragon's blood is a rare and precious traditional medicine used by different cultures since ancient times. However, studies on enhancing the rapid accumulation of dragon's blood in Dracaena cambodiana and determining its formation mechanism are unavailable. In this study, the activities of two fungi, namely, BJDC01 and BJDC05, and their effect on promoting the accumulation of five main compositions of dragon's blood in D. cambodiana were investigated for the first time. Results of field tests conducted for ten months indicated that the contents of Loureirin D, 4,4'-dihydroxy-2'-dimethoxychalcone, Loureirin A and Loureirin B in two fungal-inoculated materials were 1.67 to 2.85 times greater than those of natural samples, and thus were significantly higher than those of the control groups. The content of 4,4'-dihydroxy-2'6'-dimethoxydihydrochalcone in each fungal-inoculated sample was close to that of the natural sample, and was more than twice of each of the control group. By combining the results of morphological characterizations, both BJDC01 and BJDC05 can stimulate the accumulation of the compositions of dragon's blood. This stimulation may be considered as a defense response of D. cambodiana tree against the invasion of foreign fungi. Thus, this study provides a potential way of producing dragon's blood via the inoculation of two fungal elicitors.

Sclerotial formation of Polyporus umbellatus by low temperature treatment under artificial conditions.

BACKGROUND: Polyporus umbellatus sclerotia have been used as a diuretic agent in China for over two thousand years. A shortage of the natural P. umbellatus has prompted researchers to induce sclerotial formation in the laboratory. METHODOLOGY/PRINCIPAL FINDING: P. umbellatus cultivation in a sawdust-based substrate was investigated to evaluate the effect of low temperature conditions on sclerotial formation. A phenol-sulfuric acid method was employed to determine the polysaccharide content of wild P. umbellatus sclerotia and mycelia and sclerotia grown in low-temperature treatments. In addition, reactive oxygen species (ROS) content, expressed as the fluorescence intensity of mycelia during sclerotial differentiation was determined. Analysis of ROS generation and sclerotial formation in mycelia after treatment with the antioxidants such as diphenyleneiodonium chloride (DPI), apocynin (Apo), or vitamin C were studied. Furthermore, macroscopic and microscopic characteristics of sclerotial differentiation were observed. Sclerotia were not induced by continuous cultivation at 25°C. The polysaccharide content of the artificial sclerotia is 78% of that of wild sclerotia. In the low-temperature treatment group, the fluorescent intensity of ROS was higher than that of the room temperature (25°C) group which did not induce sclerotial formation all through the cultivation. The antioxidants DPI and Apo reduced ROS levels and did not induce sclerotial formation. Although the concentration-dependent effects of vitamin C (5-15 mg mL(-1)) also reduced ROS generation and inhibited sclerotial formation, using a low concentration of vitamin C (1 mg mL(-1)) successfully induced sclerotial differentiation and increased ROS production. CONCLUSIONS/SIGNIFICANCE: Exposure to low temperatures induced P. umbellatus sclerotial morphogenesis during cultivation. Low temperature treatment enhanced ROS in mycelia, which may be important in triggering sclerotial differentiation in P. umbellatus. Moreover, the application of antioxidants impaired ROS generation and inhibited sclerotial formation. Our findings may help to provide new insights into the biological mechanisms underlying sclerotial morphogenesis in P. umbellatus.

Simultaneous structural identification of natural products in fractions of crude extract of the rare endangered plant Anoectochilus roxburghii using H NMR/RRLC-MS parallel dynamic spectroscopy.

Nuclear magnetic resonance/liquid chromatography-mass spectroscopy parallel dynamic spectroscopy (NMR/LC-MS PDS) is a method aimed at the simultaneous structural identification of natural products in complex mixtures. In this study, the method is illustrated with respect to (1)H NMR and rapid resolution liquid chromatography-mass spectroscopy (RRLC-MS) data, acquired from the crude extract of Anoectochilus roxburghii, which was separated into a series of fractions with the concentration of constituent dynamic variation using reversed-phase preparative chromatography. Through fraction ranges and intensity changing profiles in (1)H NMR/RRLC-MS PDS spectrum, (1)H NMR and the extracted ion chromatogram (XIC) signals deriving from the same individual constituent, were correlated due to the signal amplitude co-variation resulting from the concentration variation of constituents in a series of incompletely separated fractions. 1H NMR/RRLC-MS PDS was then successfully used to identify three types of natural products, including eight flavonoids, four organic acids and p-hydroxybenzaldehyde, five of which have not previously been reported in Anoectochilus roxburghii. In addition, two groups of co-eluted compounds were successfully identified. The results prove that this approach should be of benefit in the unequivocal structural determination of a variety of classes of compounds from extremely complex mixtures, such as herbs and biological samples, which will lead to improved efficiency in the identification of new potential lead compounds.

Quantitative determination of five glucosyloxybenzyl 2-isobutylmalates in the tubers of Gymnadenia conopsea and Coeloglossum viride var. bracteatum by HPLC.

Glucosyloxybenzyl 2-isobutylmalates are one group of important active constituents in the tubers of Gymnadenia conopsea R. Br. and Coeloglossum viride (L.) Hartm. var. bracteatum (Willd.). For the purpose of quality evaluation of these two Chinese herbal medicines, it is necessary to use a rapid and reliable assay that is suitable for the determination of their active constituents. A high-performance liquid chromatography method is firstly developed for the simultaneous quantification of five glucosyloxybenzyl 2-isobutylmalates in the tubers. The analytes including dactylorhin B, dactylorhin E, loroglossin, dactylorhin A, and militarine are isolated from the tubers of G. conopsea. The compounds are separated on an Agilent Hydrosphere C(18) (150 x 4.6 mm i.d., 5 microm) column using a mobile phase of acetonitrile-water including 0.3% acetic acid (adjusted with 36% acetic acid) with gradient elution at a flow rate of 1.0 mL/min. Detection is set at a UV wavelength of 221.5 nm. The recovery of the method is 97.7-101.0%, and linearity (r > 0.9998) is obtained for all the analytes. The assay is successfully applied to determine the contents of the analytes in the tubers of G. conopsea and C. viride var. bracteatum collected from different regions of China.

New bibenzyl derivatives from the tubers of Pleione yunnanensis.

Four new bibenzyl derivatives, shancigusins A-D (1-4) and five known bibenzyls (5-9) were isolated from the tubers of Pleione yunnanensis (Orchidaceae). The structures of these compounds were determined by extensive analyses of their spectroscopic data.

[Advances in studies on chemical components and pharmacology of epiphytic type medicinal plants in the Orohid family].

Many of the epiphytic Orchids are used as traditional Chinese medicine. The chemical components and pharmacology have been studied in recent 15 years. This article reviewed the studies which will be beneficial to reveal the relatives among these medicinal plants in the Orchid Family and be helpful to develop new drugs.

[Studies on chemical components and pharmacological activities of geobiontic type medicinal plants in Orchidaceae family].

Geobiontic type medicinal plants subjected to Orchidaceae family are used as important traditional Chinese medicine. Scientists are paying more attentions to their chemical components and pharmacology recently. This paper reviewed their chemical components involved in phenanthrene, bibenzene, flavone, sterol, terpenes, alkoloids and pharmacology such as antibacterium, cytotoxic activity, antihyperliposis effects. All these information are beneficial to reveal the relative among these medicinal plants in Orchidaceae family and are helpful to develop new drugs.

[Study on chemical constituents in herbs of Anoectochilus roxburghii II].

OBJECTIVE: To study the chemical constituents of Anoectochilus roxburghii. METHOD: Silica gel and sephadex LH-20 column chromotography were used in the isolation from the ethanol extracts of the whole plant, the compounds were determined on the basis of various modern spectroscopic analysis and physical constants. RESULT: Five compounds were isolated from the CHCl3 soluble portion, identified as p-Hydroxybenzaldehyde (I), ferulic acid (II), quercetin (III), daucosterol (IV), cirsilineol (V). CONCLUSION: All these compounds were isolated from the plant for the first time, compound V was isolated from the Orchid Family for the first time, the other compounds were isolated from this genus for the first time.

[Study on HPLC-FPS of Pueraria of different sources].

OBJECTIVE: To make comparative study on HPLC-FPS of several kinds of Pueraria lobata and P. thomsonii from different sources. METHOD: Kromasil C18 column was used, with mixture of acetonitrile and water as mobile phase in a gradient mode. The wavelength of measurement was 250 nm. RESULT AND CONCLUSION: The fingerprints of P. lobata and P. thomsonii were obtained. This method can be used to identify P. lobata and P. thomsonii from different sources conveniently, and it may be practically valuable for the quality control of sample for P. lobata or P. thomsonii and its preparation.