Dendrobium Candidum Research Articles

Chemical constituents of Dendrobium candidum

The column chromatography on silica gel, sephadex LH-20 preparative HPLC were used to separate and purify the compounds from the stems of Dendrobium candidum. Twenty compounds were isolated and identified as 3,4'-dihydroxy-5-methoxybibenzyl(1), dihydroresveratrol(2), dendromoniliside E(3), denbinobin(4),2,4,7-trihydroxy-9, 10-dihydrophenanthrene(5), aduncin(6), (-)-loliolide(7), adenosine(8), uridine(9), guanosine(10), sucrose(11), 5-hydroxymethyl-furaldehyde(12), n-octacostyl ferulate(13), defuscin(14), n-triacontyl cis-p-coumarate(15), daucosterol(16), beta-sitosterol(17), hexadecanoic acid(18), hentriacontane(19), and heptadecanoic acid(20). Their structures were elucidated on the basis of spectroscopic data and physicochemical properties. All of the compounds were isolated from this plant for the first time.

Quantitive variation of polysaccharides content in cultivatedDendrobium candidum

To reveal the variation content of polysaccharides in cultivated Dendrobium candidum and the relationship between germplasms, harvesting and polysaccharides content for the breeding of quality of D. candidium. The morphological characteristics were recorded when 33 samples were collected. The content of polysaccharides was determined by phenol-sulphuric acid method. The average content of polysaccharides in 2-year-old samples was 34.47% (25.63%-41.65%). The polysaccharides content of samples were significantly different among germplasms and physiological ages. The polysaccharides content of cultivated D. candidum is higher than that of wild materials. Germplasms and physiological age impact on the polysaccharides content significantly. D. candidum breeding and the control of harvesting can increase polysaccharides content.

In vitro Antioxidant Activity of Polysaccharides with Different Molecular Weights from Dendrobium candidum

Crude polysaccharide from Dendrobium candidum (DSP) was successively fractionated with different concentration ethanol and three polysaccharides named DSP1, DSP2 and DSP3 were obtained at the concentrations of 90%, 70% and 40%, respectively. Subsequently, DSP and its three fractions were tested for antioxidant activity in vitro. Results showed that DSP1 had the strongest DPPH radical scavenging activity, total antioxidant activity, inhibition against Fe2+-VC-induced lipid peroxidation and inhibition against erythrocyte hemolysis induced by H2O2, DSP and DSP3 took the second place and DSP2. had the weakest biological activities. The hydroxyl radical scavenging capacity of these test samples followed the order of DSP DSP3 DSP1 DSP2. In addition, all fractions of Dendrobium candidum polysaccharides showed potential for protecting against DNA damage mediated by hydroxyl radicals. These results suggested that polysaccharides from Dendrobium candidum had antioxidant potential, which might be closely associated with their molecule weight.

Cryopreservation of Dendrobium candidum Wall. ex Lindl. protocorm-like bodies by encapsulation-vitrification

Protocorm-like bodies (PLBs) of Dendrobium candidum Wall. ex Lindl., orchid, were successfully cryopreserved using an encapsulation vitrification method. PLBs were precultured in liquid Murashige and Skoog (MS) medium containing 0.2 mg l−1 α-naphthalene acetic acid and 0.5 mg l−1 6-benzyladenine enriched with 0.75 M sucrose, and grown under continuous light (36 μmol m−2 s−1) at 25 ± 1°C for 5 days. PLBs were osmoprotected with a mixture of 2 M glycerol and 1 M sucrose for 80 min at 25°C and dripped in a 0.5 M CaCl2 solution containing 0.5 M sucrose at 25 ± 1°C and left for 15 min to form Ca-alginate beads (about 4 mm in diameter). Then, these were dehydrated with a plant vitrification solution 2 (PVS2) consisting of 30% (w/v) glycerol, 15% (w/v) ethylene glycol, and 15% (w/v) dimethyl sulfoxide in 0.5 M sucrose, pH 5.8, for 150 min at 0°C. Encapsulated and dehydrated PLBs were plunged directly into liquid nitrogen for 1 h. Cryopreserved PLBs were then rapidly re-warmed in a water bath at 40°C for 3 min and then washed with MS medium containing 1.2 M sucrose for three times at 10 min intervals. Within 60 days, plantlets with the cryopreserved PLBs developed normal shoots and roots, and without any observed morphological abnormalities, were obtained. The survival rate of encapsulated-vitrified PLBs was above 85%. Thus, this encapsulation-vitrification method was deemed promising for cryopreservation of PLBs of D. candidum.

Identification and classification of Dendrobium candidum species by fingerprint technology with capillary electrophoresis

A capillary electrophoresis fingerprint method was established to evaluate the quality of Dendrobium candidum. The method of sample preparation and the electrophoresis condition were optimized to obtain highly sensitive and specific capillary electropherogram. The analysis was performed on a fused-silica capillary (65 cm×75 µm i.d). The detection wavelength was 195 nm and a voltage of 20 kV was applied. The background electrolyte was a 40 mmol/L sodium borate solution (5% methanol, v/v) adjusted to pH 9.5 with 0.1 mmol/L NaOH solution. Medicinal materials were extracted by ethanol reflux for 2 h. The capillary electrophoresis fingerprints of 69-sample of Dendrobium candidum species from 10 different areas showed 15 characteristic peaks which could be applied to identification of this species. The coefficients were from 0.854 to 0.963 between standard fingerprint and each sample. The quantitative data of the fingerprints were analyzed by principal component analysis (PCO), UPGMA cluster analysis and the results showed that samples from different regions could be divided into three groups. Moreover, a rapid and convenient discriminant function was established to classify the Dendrobium candidum plants. The data revealed that the coincidence rate of all samples attached 100% by this discriminant model. The method is reliable and could be used to control the quality of medicinal plants including Dendrobium candidum species in the future.

ChemInform Abstract: Two New Compounds from Dendrobium candidum.

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Four New Bibenzyl Derivatives from Dendrobium candidum

Four new bibenzyl derivatives, namely, dendrocandins F-I (1-4), were isolated from the stems of Dendrobium candidum. Their structures were elucidated by the analysis of spectroscopic data. Dendrocandins F and G represent the fourth and fifth example of bisbibenzyl derivates with a dibenzopyran ring between two units, respectively. Dendrocandin H represents the first example of a bibenzyl derivative formed by a bibenzyl and a 1,4-phenanthraquinone unit via a dibenzopyran ring. Compounds 1-4 were examined for antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay.

Three New Bibenzyl Derivatives from Dendrobium candidum

Three new compounds were isolated from the stems of Dendrobium candidum: (S)-3,4,4'-trihydroxy-5,alpha-dimethoxybibenzyl (1), named dendrocandin C; (S)-3,4,4'-trihydroxy-5-methoxy-alpha-ethoxybibenzyl (2), named dendrocandin D; and 3,3',4,4'-tetrahydroxy-5-methoxybibenzyl (3), named dendrocandin E. Their structures were elucidated by 1D- and 2D-NMR spectroscopy and mass spectroscopy. The isolated compounds exhibited potent antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging test, with IC(50) values of 34.2, 34.5, and 15.6 microM for compounds 1, 2, and 3, respectively. Vitamin C was used as positive control with IC(50) 23.2 microM.

Genetic characterization of the nine medicinal Dendrobium species using RAPD

The nine species of Dendrobium were distinguished from each other by the banding pattern generated by the sixteen 10-mer oligonucleotide primers in the random amplified polymorphic DNA (RAPD) reaction. Distinctive bands generated from the nine species were observed. RAPD analysis was also applied to estimate the genetic relationship among the nine species. A dendrogram was constructed based on a data matrix of 323 polymorphic bands originated by the sixteen random primers. Four groups were identified, one consisting of Dendrobium huoshanense and Dendrobium loddigesii, the second consisting of Dendrobium bellatulum and Dendrobium fimbriatum. The third cluster contained Dendrobium candidum, Dendrobium densiflorum and Dendrobium exile. The rest were grouped in the fourth cluster. The principal coordinate analysis (PCA), that is, the plot drawn on the basis of the RAPD data, clearly distinguished the nine species into four groups, which also support the notion in the dendrogram described above.

First report of Phytophthora nicotianae causing blight of Dendrobium candidum in Zhejiang province, China

First report of Phytophthora nicotianae causing blight of Dendrobium candidum in Zhejiang province, China

Protocorm-like body (PLB) formation and plant regeneration from the callus culture of Dendrobium candidum Wall ex Lindl.

An efficient system was established for a higher frequency of protocorm-like body (PLB) formation from the callus of Dendrobium candidum Wall ex Lindl. The calluses were induced from longitudinally bisected segments of protocorms and subcultured two times every 40d on Murashige and Skoog medium with macronutrients at half strength, micronutrients at full strength, 2% sucrose, and with 8.8μM 6-Benzylaminopurine. PLB formation was achieved when calluses were transferred onto the same basal medium without any plant growth regulators. PLBs developed into intact plantlets about 2cm in height and with four roots when on basal medium with 2.7μM 1-naphthaleneacetic acid. Plantlets were transplanted into vermiculite with a 95% survival rate in a greenhouse. Histological observations proved that globular somatic embryos could be produced from the inside and surface of the embryogenic callus during PLB formation.

Two New Compounds from Dendrobium candidum

Two new compounds were isolated from the stems of Dendrobium candidum: (R)-3,4-dihydroxy-5,4',alpha-trimethoxybibenzyl (1), named dendrocandin A; and 4-[2-[(2S,3S)-3-(4-hydroxy-3,5-dimethoxyphenyl)-2-hydroxymethyl-8-methoxy-2,3-dihydrobenzo[1,4]dioxin-6-yl]ethyl]-1-methoxyl benzene (2), dendrocandin B. Five previously known bibenzyls were also identified: 4,4'-dihydroxy-3,5-dimethoxybibenzyl (3), 3,4-dihydroxy-5,4'-dimethoxybibenzyl (4), 3-O-methylgigantol (5), dendrophenol (6), and gigantol (7).

Effect of sound wave stress on antioxidant enzyme activities and lipid peroxidation of Dendrobium candidum

The effect of sound wave stress on important medicinal plant, Dendrobium candidum Wall. ex Lindl, was investigated, including the responses on malondialdehyde (MDA) content, the activities change of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX). Results were found that the activities of SOD, CAT, POD and APX enhanced totally in different organs of D. candidum, as leaves, stems and roots, in response to the stress. Furthermore there happened similar shift of antioxidant enzymes activities, which increased in the initial stimulation and decreased afterwards. Data showed SOD, CAT, POD and APX activities ascended to max at day 9, 6, 9 and 12 in leaves, at day 9, 6, 12 and 9 in stems, and at day 12, 6, 9 and 9 in roots, respectively. As a lipid peroxidation parameter, MDA content in different organs increased in the beginning, dropped afterward, and increased again in the late. Anyway the total trend was the rise of MDA level compared to the control. It was interesting that the MDA content appeared the lowest levels almost when the antioxidant enzymes activities were up to the highest. Our results demonstrated the different organs of D. candidum might produce accumulation of active oxygen species (AOS) under initial treatment of sound wave stress. Later AOS might start to reduce due to the enhancement of antioxidant enzymes activities treated by the stress. The data revealed that the antioxidant metabolism was to be important in determining the ability of plants to survive in sound stress, and the up regulation of these enzymes activities would help to reduce the build up of AOS, which could protect plant cells from oxidative damage. Moreover, different cell compartments might activate different defensive system to reduce excessive amount of AOS. Finally the mechanism of this action was also discussed simply.

Ultrastructural characters of a Physarum melleum on living leaves of Dendrobium candidum in China

A known species, Physarum melleum, was found fruiting on living leaves of Dendrobium candidum, which was collected in China in 2004. Its morphological characters were revealed by light microscopy (LM), environmental scanning electron microscopy (ESEM) and scanning electron microscopy (SEM). Character variations were distinguished by its olive-yellow peridium and its always thinner capillitium containing globulose granular material between the large calcareous nodes. The calcium carbonate granules, deposited on stalks, peridium and hypothallus as well as within stalks, were globose and smooth.

High-frequency shoot regeneration through transverse thin cell layer culture in Dendrobium Candidum Wall Ex Lindl.

An efficient in vitro propagation protocol for Dendrobium candidum Wall ex Lindl. using transverse thin cell layer (tTCL) culture system was established. The frequency of shoot regeneration and the number of adventitious buds produced from the regenerated shoots significantly relied on the concentration of plant growth regulators, and the position and orientation of the explant. Murashige and Skoog (MS) medium with half-strength macronutrients and 2% sucrose, supplemented with 1.2 mg l−1 naphthaleneacetic acid (NAA) and 1.2 mg l−1 6-benzyladenine (6-BA), was optimal for shoot regeneration. Upon this medium, the youngest explant inoculated in the upright orientation exhibited a high frequency of shoot regeneration (92%), and the highest number of adventitious buds (an average of 24.5) per explant. Rooting of shoots and adventitious buds was achieved on MS medium with half-strength macronutrients and 2% sucrose with 1.0 mg l−1 NAA and 1.0 mg l−1 indole-3-acetic acid (IAA). Plantlets were transplanted into vermiculite with a 95% survival rate in a greenhouse. Ontogenetic studies revealed that the shoots originated from the stem vascular bundles.

An electrochemical approach to monitor pH change in agar media during plant tissue culture

In this work, metal oxide microelectrodes were developed to monitor pH change in agar media during plant tissue culture. An antimony wire was produced by a new approach “capillary melt method”. The surface of the obtained antimony wire was oxidized in a potassium nitrate melt to fabricate an antimony oxide film for pH sensing. Characterization results show that the oxide layer grown on the wire surface consists of Sb 2O 3 crystal phase. The sensing response, open-circuit potential, of the electrode has a good linear relationship ( R 2 = 1.00) with pH value of the test solution. Adding organic compounds into the test media would not affect the linear relationship, although the slope of the lines varied with different ingredients added. The antimony oxide electrodes were employed to continuously monitor pH change of agar culture media during a 2-week plant tissue culture of Dendrobium candidum. The antimony oxide electrode fabricated this way has the advantages of low cost, easy fabrication, fast response, and almost no contamination introduced into the system. It would be suitable for in situ and continuous pH measurement in many bio applications.

The biopesticide market for global agricultural use

The biopesticide market for global agricultural use

In vitro propagation of the chinese medicinal plant, Dendrobium candidum wall. ex lindl., from axenic nodal segments

Dendrobium candidum Wall. Ex Lindl. is an important species used in the formulation of Shih-hu, a Chinese traditional medicine. An efficient protocol for in vitro propagation of D. candidum using the axenic nodal segments of the shoots, originated from the in vitro germinated seedlings, was developed. The seeds from 120-d-old capsules after pollination were first germinated on half-strength Murashige and Skoog (MS) basal medium supplemented with 30 g l−1 sucrose. After 4 mo., the seedlings were subcultured on a similar medium supplemented with 1 ml l−1 HYPONeX, 80 g l−1 potato homogenate and 2 g l−1 activated charcoal for further growth. Axenic nodal segments excised from 9-mo.-old seedlings were cultured on the medium in the presence of 2 mg l−1 benzyladenine (BA) and 0.1 mg l−1 naphthaleneacetic acid (NAA). After 75 d, 73.2% of the explants gave rise to buds/shoots. The elongated shoots were rooted on the medium containing 0.2 mg l−1 NAA and the plantlets were successfully acclimatized in soil.

A method for isolating functional RNA from callus of Dendrobium candidum contented rich polysaccharides

Isolation of high-quality RNA from Dendrobium candidum is particularly difficult. D. candidum contains considerable amounts of polysaccharides that coprecipitate with RNA, which render RNA unsuitable for either cDNA synthesis and/or PCR amplification. In this paper, a rapid and efficient method was described for functional RNA isolation from the callus of D. candidum. The procedure included: (i) an extraction with phenol and isopropyl alcohol, to remove proteins and polyphenols; (ii) purifications by lithium chloride, pre-cooled (−20 °C) ethanol successively to remove polysaccharides. The method resulted in high-quality RNA suitable for DDRT-PCR and cDNA library analysis finally.

Accumulation of soluble sugars, heat-stable proteins and dehydrins in cryopreservation of protocorm-like bodies of Dendrobium candidumby the air-drying method

Summary Protocorm-like bodies (PLBs) of Dendrobium candidum were successfully cryopreserved by the air-drying method. The optimal water content before freezing seemed to be at the range of 0.1 g H 2 O/g DW (11 % on fresh weight basis) to 0.5 g H 2 O/g DW (33 % on fresh weight basis). Changes in soluble sugars, heat-stable proteins and dehydrins during desiccation of PLBs were analyzed. Extensive accumulation of soluble sugars was observed at water content of about 7.2 g H 2 O/g DW (after 24 h desiccation), and the sugars content did not increase further during the following desiccation. The amount of heat-stable protein increased significantly when water content decreased to 1.0 g H 2 O/g DW (after approximately 66 h desiccation). Results from immunological detection showed that two bands of the heat-stable proteins with respective molecular masses of 28.7 and 34.3 kDa were dehydrins which appeared when water content dropped to 1.0 g H 2 O/g DW. Therefore, it seemed that accumulation of dehydrins happened later than that of soluble sugars. Interestingly, exogenous ABA treatment of PLBs before desiccation could also induce the accumulation of soluble sugars, heat-stable proteins and dehydrins. The possible roles of these substances in the acquisition of dehydration and freezing tolerance were discussed.