Kalin Yanbo Zhang

Review of research on Dendrobium, a prized folk medicine.

Medicinal plants of the Dendrobium genus are highly prized, and hence, methodologies have been developed to authenticate Dendrobium drugs from its adulterants. Many bioactive constituents of Dendrobium species have been identified. The macromolecules included lectins; the enzymes chalcone synthase, sucrose synthase, and cytokinin oxidase; and polysaccharides. The polysaccharides display immunomodulatory and hepatoprotective activities. Alkaloids exhibit antioxidant, anticancer, and neuroprotective activities. Other compounds manifest antioxidant, anticancer, and immunomodulatory.

Baicalein antagonizes rotenone-induced apoptosis in dopaminergic SH-SY5Y cells related to Parkinsonism

BackgroundTwo active compounds, baicalein and its glycoside baicalin were found in the dried root of Scutellaria baicalensis Georgi, and reported to be neuroprotective in vitro and in vivo. This study aims to evaluate the protective effects of baicalein on the rotenone-induced apoptosis in dopaminergic SH-SY5Y cells related to parkinsonism.MethodsCell viability and cytotoxicity were determined by MTT assay. The degree of nuclear apoptosis was evaluated with a fluorescent DNA-binding probe Hoechst 33258. The production of reactive oxidative species (ROS) and loss of mitochondrial membrane potential (ΔΨm) were determined by fluorescent staining with DCFH-DA and Rhodanmine 123, respectively. The expression of Bax, Bcl-2, cleaved caspase-3 and phosphorylated ERK1/2 was determined by the Western blots.ResultsBaicalein significantly increased viability and decreased rotenone-induced death of SH-SY5Y cells in a dose-dependent manner. Pre- and subsequent co-treatment with baicalein preserved the cell morphology and attenuated the nuclear apoptotic characteristics triggered by rotenone. Baicalein antagonized rotenone-induced overproduction of ROS, loss of ΔΨm, the increased expression of Bax, cleaved caspase-3 and phosphorylated ERK1/2 and the decreased expression of Bcl-2.ConclusionThe antioxidative effect, mitochondrial protection and modulation of anti-and pro-apoptotic proteins are related to the neuroprotective effects of baicalein against rotenone induced cell death in SH-SY5Y cells.

Cordymin, an antifungal peptide from the medicinal fungus Cordyceps militaris

Cordymin, an antifungal peptide with a molecular mass of 10,906 Da and an N-terminal amino acid sequence distinct from those of previously reported proteins, was purified from the medicinal mushroom Cordyceps militaris. The isolation protocol comprised ion exchange chromatography of the aqueous extract on SP-Sepharose and Mono S and gel filtration on Superdex 75 by a fast protein liquid chromatography system. Cordymin was adsorbed on both cation exchangers. The peptide inhibited mycelial growth in Bipolaris maydis, Mycosphaerella arachidicola, Rhizoctonia solani and Candida albicans with an IC(50) of 50 μM, 10 μM, 80 μM, and 0.75 mM, respectively. However, there was no effect on Aspergillus fumigatus, Fusarium oxysporum and Valsa mali when tested up to 2 mM. The antifungal activity of the peptide was stable up to 100°C and in the pH range 6-13, and unaffected by 10 mM Zn(2+) and 10 mM Mg(2+). Cordymin inhibited HIV-1 reverse transcriptase with an IC(50) of 55 μM. Cordymin displayed antiproliferative activity toward breast cancer cells (MCF-7) but there was no effect on colon cancer cells (HT-29). There was no mitogenic activity toward mouse spleen cells and no nitric oxide inducing activity toward mouse macrophages when tested up to 1 mM.

Dendrobium candidum extract increases the expression of aquaporin-5 in labial glands from patients with Sjögren's syndrome.

This study aimed to investigate the mechanism of Dendrobium candidum extract in promoting expression of aquaporin-5 for treatment of Sjögrens syndrome (SS). Sixteen patients with SS suffered from deficient secretion of saliva due to an autoimmune destruction of salivary glands leading to dry mouth symptoms (xerostomia). However, glandular dysfunction also occurred without destruction. Based upon its abnormal distribution in SS salivary glands, a potential role of the water channel protein aquaporin-5 (AQP-5) in the pathogenesis of SS was proposed. After oral administration of D. candidum extracted liquid (DCEL) for 1 week, saliva and salivary gland biopsies from labial glands of patients were collected and examined by employing immunoreactivity and immunohistochemistry techniques. Results showed that salivary secretion increased by about 65% in patients treated with DCEL as compared with the control group. Higher labeling indices (percentage of acinus area immunoreactive for AQP-5) in the biopsies were found in SS patients who had taken DCEL. This study demonstrated that D. candidum would regulate the expression of AQP-5 in labial glands of SS patients and thereby promoted secretion of saliva to improve dry mouth symptoms.

Glyceollin, a soybean phytoalexin with medicinal properties

This review covers the biosynthesis of glyceollin and its biological activities including antiproliferative/antitumor action (toward B16 melanoma cells, LNCaP prostate cancer cells, and BG-1 ovarian cancer cells), anti-estrogenic action (through estrogen receptors α- and β-), antibacterial action (toward Erwinia carotovora, Escherichia coli, Bradyrhizobium japonicum, Sinorhizobium fredii ), antinematode activity, and antifungal activity (toward Fusarium solani, Phakospora pachyrhizi, Diaporthe phaseolorum, Macrophomina phaseolina, Sclerotina sclerotiorum, Phytophthora sojae, Cercospora sojina, Phialophora gregata, and Rhizoctonia solani). Other activities include insulinotropic action and attenuation of vascular contractions in rat aorta.

Application of SCAR (sequence characterized amplified region) analysis to authenticate Lycium barbarum (wolfberry) and its adulterants

Fructus Lycii (Gouqizi) is well known in Chinese herbal medicine for its restorative function of benefiting the liver and kidney, replenishing vital essence and improving eyesight. However, ten species and varieties of Lycium have benn found to be substitutes or adulterants of Lycium barbarum (wolfberry) in commercial markets in the Hong Kong Special Administrative Region and in China generally. L. barbarum cv. ‘Tianjinense’ and Lycium chinense var. potaninii are the most common examples. It is difficult to differentiate among the Lycium species by traditional morphological and histological analyses. An easy and reliable approach based on SCAR (sequence characterized amplified region) analysis was developed in the present study to differentiate L. barbarum from other Lycium species. Two characteristic bands of approx. 700 and 650 bp were detected on the RAPD (random amplification of polymorphic DNA) profiles generated from samples of L. barbarum and L. chinense var. potaninii using the primer OPC‐7. They were isolated and sequenced. Two primer sets, based on the sequences, could amplify a single specific band in samples of L. barbarum respectively, whereas no bands were detected in samples of L. chinense var. potaninii. The results confirmed that the SCAR technique can be employed for authenticating L. barbarum and its adulterants.

Purification and characterization of a laccase with inhibitory activity toward HIV-1 reverse transcriptase and tumor cells from an edible mushroom (pleurotus cornucopiae)

A 66-kDa laccase, with an N-terminal sequence different from those of other mushroom laccases, was purified from fresh fruiting bodies of the edible mushroom Pleurotus cornucopiae by using affinity chromatography on Affi-gel blue gel, ion exchange chromatography on Mono Q and gel filtration on Superdex 75. The procedure resulted in a 16-fold purification and a specific enzyme activity of 17.3 U mg(-1). The optimum pH and temperature for the purified laccase were pH 4 and 40 degrees C, respectively. This laccase inhibited proliferation of murine leukemia cell line L1210 and human hepatoma cell line HepG2, and reduced the activity of HIV-1 reverse transcriptase with an IC50 of 22 microM. There was neither mitogenic activity toward mouse splenocytes, nor hemagglutinating/hemolytic activity toward rabbit erythrocytes. This study yielded information about the potentially exploitable activities of P. cornucopiae laccase.

Evaluation of chemical constituents and important mechanism of pharmacological biology in dendrobium plants.

Dendrobium species, commonly known as “Shihu” or “Huangcao,” represents the second largest genus of Orchidaceae, which are used commonly as tonic herbs and healthy food in many Asian countries. The aim of this paper is to review the history, chemistry, and pharmacology of different Dendrobium species on the basis of the latest academic literatures found in Google Scholar, PubMed, Sciencedirect, Scopus, and SID.

Protective effect of Dendrobium officinale polysaccharides on experimental Sjogren's syndrome

Sjogrens syndrome (SS), usually described as a chronic inflammation which results in xerostomia (dry mouth) and xerophthalmia (dry eyes). According to the theory of traditional Chinese medicine, body fluid impairment causes the dryness, inducing water secretion deficiency. Discovery of a family of water-specific membrane channel proteins, the aquaporins, provides an interesting molecular mechanism of water permeability and transportation which were found abnormal in tissues of SS patients. Thus, this dryness may lead to the dysfunction in organs as various systematic manifestations. We established an autoallergic mouse model in vivo, and human salivary gland cell line A-253 in vitro. Polysaccharides of Dendrobium officinale (DP) were administrated as treatment, which was described to nourish yin and promote the body fluid. Results showed that immunization with SG autoantigen induced decrease of body weight and increased water intake, decreased AQP5 expression in a series of organs related to body fluid. Sera from model mice induced apoptosis of A-253 cells with activation of caspase-3. Administration of DP could reverse these pathological changes in both the animal and cell model. Thus, DP may be a promising candidate for the treatment of SS by up-regulating the expression of AQP-5 and protecting cells from apoptosis.

Network pharmacological identification of active compounds and potential actions of Erxian decoction in alleviating menopause-related symptoms.

BackgroundErxian decoction (EXD) is used to treat menopause-related symptoms in Chinese medicine. This study aims to identify the bioactive compounds and potential actions of EXD by network pharmacological analysis.MethodsTwo databases, the Traditional Chinese Medicine Systems Pharmacology database and TCM Database@Taiwan, were used to retrieve literature of phytochemicals of EXD. STITCH 4.0 and the Comparative Toxicogenomics Database were used to search for compound–protein and compound–gene interactions, respectively. DAVID Bioinformatics Resources 6.7 and Cytoscape 3.01 with Jepetto plugin software were used to perform a network pharmacological analysis of EXD.ResultsA total of 721 compounds were identified in EXD, of which 155 exhibited 2,656 compound–protein interactions with 1,963 associated proteins determined by STITCH4.0 database, and of which 210 had 14,893 compound–gene interactions with 8,536 associated genes determined by Comparative Toxicogenomics Database. Sixty three compounds of EXD followed the Lipinski’s Rule with OB ≥30% and DL index ≥0.18, of which 20 related to 34 significant pathway- or 12 gene- associated with menopause.ConclusionsTwenty compounds were identified by network pharmacology as potential effective ingredients of EXD for relieving menopause with acceptable oral bioavailability and druggability.