Molecular properties and immunomodulatory activities of a water-soluble heteropolysaccharide isolated from Plantago asiatica L. leaves.

This study aims at investigating physical-chemical properties of a water-soluble heteropolysaccharide from Plnatago asiatica L. leaves, and its immunomodulatory effects on macrophages RAW264.7 cells. Hot water-extracted crude polysaccharide from the plant leaves (PLLCP) was fractionated into four fractions by DEAE Sepharose Fast Flow eluted with 0.1-0.5 M NaCl solutions. The most abundant fraction (0.3 M NaCl elution), designated PLLP-2, was identified as a heteropolysaccharide with an average molecular weight (Mw) of 3.54 × 104 and composed mainly of Gal (34.4%), GalA (36.5%), Ara (10.1%) and Rha (8.4%). PLLP-2 was an acidic polysaccharide exhibiting inflaky curly aggregation with smooth surface. PLLCP and its main subfraction PLLP-2 displayed immunomodulatory activities by stimulating the production of pro-inflammatory cytokines, including TNF-α and IL-1ß in macrophage RAW264.7 cells. These results indicate that the main polysaccharide fraction purified from P. asiatica L. leaves is probably pectin, and have potential immunomodulatory function.

Transcutaneous electrical acupoint stimulation for post-traumatic stress disorder: Assessor-blinded, randomized controlled study.

AIM: Transcutaneous electrical acupoint stimulation (TEAS) has the potential to alleviate post-traumatic stress disorder (PTSD). The purpose of this study was to determine whether adding TEAS to sertraline or cognitive behavioral therapy (CBT) could improve the anti-PTSD efficacy. METHODS: In this randomized controlled trial, 240 PTSD patients (60 in each group) were assigned to receive simulated TEAS combined with sertraline (group A) or with CBT (group B), active TEAS combined with CBT (group C), or active TEAS combined with CBT plus sertraline (group D) for 12 weeks. The outcomes were measured using the Clinician-Administered PTSD Scale, PTSD Check List-Civilian Version, and 17-item Hamilton Rating Scale for Depression. RESULTS: While PTSD symptoms reduced over time in all patients, groups C and D had markedly greater improvement in both PTSD and depressive measures than groups A and B in all post-baseline measurement points, with moderate to very large effect sizes of 0.484-2.244. Groups C and D also had a significantly higher rate than groups A and B on clinical response (85.0% and 95.0% vs 63.3% and 60.0%, P < 0.001) and on remission (15.0% and 25.0% vs 3.3% and 1.7%, P < 0.001). The incidence of adverse events was similar between groups A and D and between groups B and C. CONCLUSIONS: Additional TEAS augments the anti-PTSD and antidepressant efficacy of antidepressants or CBT, without increasing the incidence of adverse effects. TEAS could serve as an effective intervention for PTSD and comorbid depression. This trial was registered with www.chictr.org (no.: ChiCTR1800017255).

Cosmetic and Skincare Benefits of Cultivated Mycelia from the Chinese Caterpillar Mushroom, Ophiocordyceps sinensis (Ascomycetes).

Mushrooms are potential sources of novel natural cosmeceutical ingredients. This study was conducted to evaluate the cosmetic (skincare) benefits of the valuable medicinal species Ophiocordyceps sinensis (=Cordyceps sinensis). The mycelial extracts of 2 O. sinensis strains, Cs-HK1 and Cs-4, prepared sequentially with ethyl acetate, ethanol, and hot water were tested with in vitro assays for tyrosinase-, collagenase-, and elastase-inhibitory activity. The ethyl acetate extracts of both fungal strains showed potent antityrosinase and antielastase activity, with low half-maximal inhibitory concentrations (0.14-0.47 mg/mL) comparable to those of the respective reference compounds (arbutin and epigallocatechin gallate). All mycelial extracts exhibited moderate or significant anticollagenase activity; most extracts showed a significant photoprotective effect with a sun protection factor up to 25. The results from this study show the potential use of O. sinensis as a source of cosmetic ingredients for skincare applications.

Three-phase partitioning as an elegant and versatile platform applied to nonchromatographic bioseparation processes.

In recent years, a big trend has been the development of rapid, green, efficient, economical, and scalable approaches for the separation and purification of bioactive molecules from natural sources, which can be used in food, cosmetics, and medicine. As a new nonchromatographic bioseparation technology, three-phase partitioning (TPP) is attracting the attention of a growing number of scientists and engineers. Although a number of studies have been published in the last 40 years regarding the extraction, separation, and purification of numerous bioactive molecules using TPP systems, a background review on TPP partitioning fundamentals and its applications is much needed. Therefore, the present review focuses in detail on the TPP separation process, including the definition of TPP, partitioning mechanisms, parameters for establishing the suitable condition to form precipitate such as concentration of ammonium sulfate, content of tert-butanol, pH and temperature, and the application for separation and purification of protein, enzyme, plant oil, polysaccharide, and other small molecule organic compounds. In addition, the possible directions of future developments in TPP technology are discussed. The review presents a good opportunity, as well as a challenge for scientists, to understand the detailed partitioning rule and to take better use of TPP for the production and separation of various bioactive molecules, which have been intensively applied in the food and medical fields.

Antifatigue Functions and Mechanisms of Edible and Medicinal Mushrooms.

Fatigue is the symptom of tiredness caused by physical and/or psychological stresses. As fatigue is becoming a serious problem in the modern society affecting human health, work efficiency, and quality of life, effective antifatigue remedies other than pharmacological drugs or therapies are highly needed. Mushrooms have been widely used as health foods, because of their various bioactive constituents such as polysaccharides, proteins, vitamins, minerals, and dietary fiber. This paper reviews the major findings from previous studies on the antifatigue effects, the active components of mushrooms, and the possible mechanisms. Many studies have demonstrated the antifatigue effects of edible and medicinal mushrooms. These mushrooms probably mitigate human fatigue through effects on the functional systems, including the muscular, cardiovascular, hormone, and immune system. The bioactive constituents that contribute to the antifatigue effects of mushrooms may include polysaccharides, peptides, nucleosides, phenolic compounds, and triterpenoids. Further research is still needed to identify the active ingredients and to investigate their mechanism of action on the antifatigue effects. Since most previous studies have been carried out in animal models, more human trials should be performed to verify the antifatigue function of edible and medicinal mushrooms.

Biocompatible Polyelectrolyte Complex Nanoparticles from Lactoferrin and Pectin as Potential Vehicles for Antioxidative Curcumin.

Polyelectrolyte complex nanoparticles (PEC NPs) were fabricated via electrostatic interactions between positively charged heat-denatured lactoferrin (LF) particles and negatively charged pectin. The obtained PEC NPs were then utilized as curcumin carriers. PEC NPs were prepared by mixing 1.0 mg/mL solutions of heat-denatured LF and pectin at a mass ratio of 1:1 (w/w) in the absence of NaCl at pH 4.50. PEC NPs that were prepared under optimized conditions were spherical in shape with a particle size of ∼208 nm and zeta potential of ∼-32 mV. Hydrophobic curcumin was successfully encapsulated into LF/pectin PEC NPs with high encapsulation efficiency (∼85.3%) and loading content (∼13.4%). The in vitro controlled release and prominent antioxidant activities of curcumin from LF/pectin PEC NPs were observed. The present work provides a facile and fast method to synthesize nanoscale food-grade delivery systems for the improved water solubility, controlled release, and antioxidant activity of hydrophobic curcumin.

Structure and antioxidative property of a polysaccharide from an ammonium oxalate extract of Phellinus linteus.

In this paper, the novel polysaccharide PL-A11 was purified from an ammonium oxalate extract of Phellinus linteus mycelia. Its physicochemical properties, structural characteristics, and antioxidant activities were investigated. Results showed that PL-A11 had a weight-average molecular weight (Mw) of 13.8kDa and was mainly composed of arabinose, xylose, mannose, and glucose in a molar ratio of 1.1:1.3:1.0:6.6. The backbone of PL-A11 was composed of (1→4)-α-d-glucopyranosyl, (1→2)-α-d-xylopyranosyl, and (1→3)-α-d-arabinofuranosyl residues, whereas the (1→6)-α-d-mannopyranosyl residues formed branches at the O-2 position with 1-linked-α-d-glucopyranosyl terminal residues. From the antioxidative activity tests in vivo, the administration of PL-A11 obviously enhanced the activity of antioxidant enzymes and significantly reduced the level of malondiadehyde (MDA) in the serum and liver of d-galactose-treated aging mice in a dose-dependent manner, as well as effectively stimulated the immune system of aging mice. These findings implied that PL-A11 could be developed as a potential antioxidant for applications in the functional food, pharmaceutical, cosmetic or nutraceutical industries.

Contents and Antioxidant Activities of Polysaccharides in 14 Wild Mushroom Species from the Forest of Northeastern China.

This study aimed to evaluate the polysaccharide contents and antioxidant activities of 14 important wild mushroom species in the Lesser Khingan Range Forest of northeastern China. The fungal species were identified by morphology and DNA matching, belonging to six families: Polyporaceae (four species), Tricholomataceae (three), Russulaceae (three), Lepiotaceae (two), Lycoperdaceae (one), and Paxillaceae (one). Polysaccharides were isolated and partially purified from the water extract of each m ushroom by ethanol precipitation, deproteinization, and dialysis. Antioxidant activities of the mushroom polysaccharides were found to vary with both the species and the assay methods, and the highest three were from Handkea utriformis (535.8 µmol trolox/g), Macrolepiota mastoidea (378.6), and Armillaria ostoyae (329.1) in radical scavenging; H. utriformis (5.94 mmol Fe/g), Lepista nuda (4.65), and A. ostoyae (4.42) in reducing power; and Armillariela cepistipes (484.6 µmol Fe2+/g), H. utriformis (274.8), and M. mastoidea (202.5) in Fe2+ chelating. Several of the polysaccharides showed notable anti-tyrosinase activities, and that of Chroogomphus rutilus was the most potent with an IC50 of 0.46 mg/ml. These wild mushrooms can be useful sources of polysaccharides as potential antioxidants and tyrosinase inhibitors. This is the first systematic study on the wild mushroom species, as well as their polysaccharide contents and biological activities, from this forest.

Mycelial fermentation characteristics and anti-fatigue activities of a Chinese caterpillar fungus, Ophiocordyceps sinensis strain Cs-HK1 (Ascomycetes).

Mycelial fermentation of an Ophiocordyceps sinensis strain Cs-HK1 was carried out in various volumes of stirred-tank fermenters from 1.6-L and 15-L laboratory scale to 2000-L industrial scale. The mycelial growth in most fermenters had a higher rate, due probably to more efficient oxygen supply, than in shake-flasks. The mycelial fermentation was successfully scaled up to 2000-L industrial fermenters, achieving 30 g/L maximum biomass in 5 days. The Cs-HK1 mycelia formed hairy and fluffy pellets in the fermentation medium and the mycelial broth exhibited pseudoplastic rheology following the power law, with the flow behavior index n decreasing from 0.5 to 0.3, and the flow consistency K and the apparent viscosity µα increasing with time and biomass concentration. The mycelial broth containing biomass and extracellular products harvested from 2000-L fermenters was tested for anti-fatigue activities in forced animal swimming experiments. The mycelium hot water extract showed the most significant effects, increasing the swimming endurance of mice up to 100%, and also increasing the glycogen levels and reducing the lactic acid and blood urea nitrogen levels significantly. The results demonstrated the feasibility of Cs-HK1 mycelial fermentation for large-scale production of bioactive and medicinal materials.

Recent advances in Cordyceps sinensis polysaccharides: Mycelial fermentation, isolation, structure, and bioactivities: A review.

Cordyceps (Ophiocordyceps sinensis) sinensis, the Chinese caterpillar fungus, is a unique and precious medicinal fungus in traditional Chinese medicine which has been used as a prestigious tonic and therapeutic herb in China for centuries. Polysaccharides are bioactive constituents of C. sinensis, exhibiting several activities such as immunomodulation, antitumour, antioxidant and hypoglycaemic. As natural C. sinensis fruiting body-caterpillar complexes are very rare and expensive, the polysaccharides documented over the last 15-20 years from this fungal species were mostly extracted from cultivated fungal mycelia (intracellular polysaccharides) or from mycelial fermentation broth (exopolysaccharides). Extraction and purification of the polysaccharides is a tedious process involving numerous steps of liquid and solid phase separations. Nevertheless, a large number of polysaccharide structures have been purified and elucidated. However, relationships between the structures and activities of these polysaccharides are not well established. This review provides a comprehensive summary of the most recent developments in various aspects (i.e., production, extraction, structure, and bioactivity) of the intracellular and exopolysaccharides from mycelial fermentation of C. sinensis fungi. The contents and data will serve as useful references for further investigation, production and application of these polysaccharides in functional foods and therapeutic agents.

Structure and antioxidant activity of a novel poly-N-acetylhexosamine produced by a medicinal fungus.

A novel poly-N-acetylhexosamine (polyhexNAc) about 6 kDa average molecular weight (MW) was isolated from the low-MW fraction of exopolysaccharide produced by liquid fermentation of a medicinal fungus Cordyceps sinensis Cs-HK1. The composition and linkage of sugar residues were determined by mass spectrometry and methylation analysis, and the anomeric configuration and chain linkage were confirmed by NMR. From the analytical results, the molecular structure was elucidated as a [-4-ß-D-ManNAc-(1→3)-ß-D-GalNAc-(1→] disaccharide repeating unit in the main chain with a Gal branch occurring randomly at the 3-position of ManNAc. This polyhexNAc showed notable antioxidant activities with a Trolox equivalent antioxidant capacity of 330 µmol Trolox/g, a ferric reducing ability of plasma of 45.7 µmol Fe(II)/g, and significant cytoprotective effect against H2O2-induced PC12 cell injury. This is the first report on the structure and bioactivity of an extracellular amino-polysaccharide from the Cordyceps species.

Modeling of Fusarium redolens Dzf2 mycelial growth kinetics and optimal fed-batch fermentation for beauvericin production.

Beauvericin (BEA) is a cyclic hexadepsipeptide mycotoxin with notable phytotoxic and insecticidal activities. Fusarium redolens Dzf2 is a highly BEA-producing fungus isolated from a medicinal plant. The aim of the current study was to develop a simple and valid kinetic model for F. redolens Dzf2 mycelial growth and the optimal fed-batch operation for efficient BEA production. A modified Monod model with substrate (glucose) and product (BEA) inhibition was constructed based on the culture characteristics of F. redolens Dzf2 mycelia in a liquid medium. Model parameters were derived by simulation of the experimental data from batch culture. The model fitted closely with the experimental data over 20-50 g l(-1) glucose concentration range in batch fermentation. The kinetic model together with the stoichiometric relationships for biomass, substrate and product was applied to predict the optimal feeding scheme for fed-batch fermentation, leading to 54% higher BEA yield (299 mg l(-1)) than in the batch culture (194 mg l(-1)). The modified Monod model incorporating substrate and product inhibition was proven adequate for describing the growth kinetics of F. redolens Dzf2 mycelial culture at suitable but not excessive initial glucose levels in batch and fed-batch cultures.

Tanshinone biosynthesis in Salvia miltiorrhiza and production in plant tissue cultures.

Salvia miltiorrhiza Bunge (Lamiaceae) root, generally called Danshen, is an important herb in Chinese medicine widely used for treatment of cardiovascular diseases. Diterpenoid tanshinons are major bioactive constituents of Danshen with notable pharmacological activities and the potential as new drug candidates against some important human diseases. The importance of Danshen for traditional and modern medicines has motivated the research interest over two decades in the biosynthesis and biotechnological production of tanshinones. Although diterpenes in plants are presumably derived from the non-mevalonate (MVA) pathway, tanshinone biosynthesis in S. miltiorrhiza may also depend on the MVA pathway based on some key enzymes and genes detected in the early steps of these pathways. Plant tissue cultures are the major biotechnological processes for rapid production of tanshinones and other bioactive compounds in the herb. Various in vitro cultures of S. miltiorrhiza have been established, including cell suspension, adventitious root, and hairy root cultures, which can accumulate the major tanshinones as in the plant roots. Tanshinone production in cell and hairy root cultures has been dramatically enhanced with various strategies, including medium optimization, elicitor stimulation, and nutrient feeding operations. This review will summarize the above developments and also provide our views on future trends.

The effect of tetramethylpyrazine on hydrogen peroxide-induced oxidative damage in human umbilical vein endothelial cells.

Tetramethylpyrazine has been widely used in traditional Chinese medicine to treat cardiovascular diseases such as atherosclerosis and hypertension. The underlying mechanism of cardioprotective effects, however, remains to be elucidated. Here, using human umbilical vein endothelial cells (HUVECs), we have assessed the protective effect of tetramethylpyrazine on H(2)O(2)-induced oxidative damage. After pre-incubation with tetramethylpyrazine (50, 100 and 150 microg/ml) for 24 hr., viability loss in H(2)O(2)-induced HUVECs (76.5% of the control level, p < 0.05, at 400 microM of H(2)O(2) for 12 hr.) was restored in a concentration-dependent manner, and the maximal recovery (88.7% of the control level, p < 0.05) was achieved with tetramethylpyrazine at 150 microg/ml. The production of reactive oxygen species was suppressed by measuring fluorescent intensity of 2',7'-dichorofluorescein (83.1% of the H(2)O(2)-treated group, p < 0.05, at 150 microg/ml of tetramethylpyrazine). Tetramethylpyrazine also increased activities of superoxide dismutase and glutathione peroxidase (144.1% and 118.3% of the H(2)O(2)-treated group, respectively, p < 0.05, at 150 microg/ml of tetramethylpyrazine). In addition, tetramethylpyrazine reduced levels of malonaldehyde, intracellular nitric oxide and nitric oxide synthase (83.8%, 91.2% and 78.7% of the H(2)O(2)-treated group, respectively, p < 0.05, at 150 microg/ml of tetramethylpyrazine). Furthermore, pre-incubation of tetramethylpyrazine with HUVECs for 24 hr. resulted in reduction of apoptosis and removal of cell cycle arrest in the S phase (56.6% and 59.7% of the H(2)O(2)-treated group, respectively, p < 0.01, at 150 microg/ml of tetramethylpyrazine). Altogether, these results suggest that tetramethylpyrazine has a protective effect on H(2)O(2)-induced oxidative damage in HUVECs due to its antioxidant and antiapoptotic properties.

Cloning and characterization of the 1-deoxy-D-xylulose 5-phosphate reductoisomerase gene for diterpenoid tanshinone biosynthesis in Salvia miltiorrhiza (Chinese sage) hairy roots.

Salvia miltiorrhiza Bunge (Chinese sage; Lamiaceae) is a valuable Chinese herbal plant, and its rhizome, known as Danshen in Chinese because of its characteristic red pigment, is the part of the plant used in herbal medicine. The red pigment in S. miltiorrhiza roots is mainly composed of numerous diterpenoid tanshinones, as the major bioactive ingredients of the herb. In plants, diterpenes are synthesized through the MEP (2-C-methyl-D-erythritol 4-phosphate) pathway in the plastids, and DXR [DXP (1-deoxy-D-xylulose 5-phosphate) reductoisomerase] is an enzyme catalysing the first step of the MEP pathway. In the present study, a full-length cDNA encoding DXR (GenBank Nucleotide Sequence Database accession no. DQ991431) was cloned from the hairy roots of S. miltiorrhiza in culture. The enzyme activity of DXR protein was verified by complementation of an Escherichia coli mutant deficient in dxr. The transcription level of the dxr gene in the hairy roots was up-regulated after exposure to hyperosmotic stress and a yeast elicitor in parallel with increased tanshinone accumulation in the hairy roots. This is the first report, to our knowledge, of elicitor-induced dxr transcription and its correlation with the accumulation of diterpenoid tanshinones in S. miltiorrhiza roots.

Ultrahigh diterpenoid tanshinone production through repeated osmotic stress and elicitor stimulation in fed-batch culture of Salvia miltiorrhiza hairy roots.

Hyperosmotic stress (OS, created with 50 g/L sorbitol) and a yeast elicitor (YE, polysaccharide fraction of yeast extract) applied to Salvia miltiorrhiza hairy root cultures had a synergistic effect on the diterpenoid tanshinone production. With a single OS+YE treatment and nutrient feeding, the total tanshinone content of roots was increased by sevenfold (from 0.2 to 1.6 mg/g dry weight (dw)) and the volumetric yield by 13-fold (from 1.95 to 27.4 mg/L) compared to the batch control culture. With repeated feeding of OS and nutrient medium in an extended fed-batch culture process (i.e., 10 mL fresh medium with 50 g/L sorbitol 25 mg/L YE, every 5 days from day 21 to day 60), the total tanshinone content of roots was increased to 18.1 mg/g dw (or 1.8 wt.%) and the volumetric tanshinone yield to 145 mg/L, which were about 100-fold and 70-fold of those, respectively, in the batch control. Another interesting finding was the presence of root fragments (fine particles) with extremely high tanshinone content in the OS+YE treated cultures. It was also possible to reuse the sorbitol medium for the hairy root growth and tanshinone production to reduce the medium expenses.

Inhibitory effects of ethyl acetate extract of Cordyceps sinensis mycelium on various cancer cells in culture and B16 melanoma in C57BL/6 mice.

The cultivated mycelium of a Cordyceps sinensis (Cs) fungus was sequentially extracted by petroleum ether (PE), ethyl acetate (EtOAc), ethanol (EtOH) and hot water. All solvent extracts except hot water extract showed a significant and dose-dependent inhibitory effect on the proliferation of four cancer cell lines, MCF-7 breast cancer, B16 mouse melanoma, HL-60 human premyelocytic leukemia and HepG2 human hepatocellular carcinoma, with IC(50) values below 132 microg/ml. The EtOAc extract, in particular, had the most potent effect against all four cancer cell lines, with IC(50) between 12 microg/ml (on B16) and 45 microg/ml (on MCF-7). In contrast, it had much lower cytotoxicity against normal mouse bone marrow cells. The EtOAc extract contained carbohydrates, adenosine, ergosterol and trace amount of cordycepin, of which ergosterol and related compounds were identified as a major class of active constituents contributing to the in vitro cytotoxicity. In an animal test, the EtOAc extract showed significant inhibiting effect on B16-induced melanoma in C57BL/6 mice, causing about 60% decrease of tumor size over 27 days. Our results suggest that the EtOAc extract of Cs fungal mycelium has strong anti-tumor activity and is a potential source of natural anti-tumor products.

Enhancement of tanshinone production in Salvia miltiorrhiza Bunge (red or Chinese sage) hairy-root culture by hyperosmotic stress and yeast elicitor.

The present study evaluates the use of hyperosmotic stress and a biotic elicitor YE (yeast elicitor; polysaccharide fraction of yeast extract) to stimulate diterpenoid tanshinone production in hairy-root culture of Salvia miltiorrhiza Bunge (Lamiaceae). Sorbitol was applied as an osmoticum at various concentrations (30-100 g/l) to the hairy-root culture in MS (Murashige and Skoog) medium [Murashige and Skoog (1962) Physiol. Plant. 15, 473-497] containing 30 g/l sucrose, and it increased the TT (total tanshinone) content of roots most dramatically at 50-70 g/l (medium osmolality 410-500 mmol/kg; 1 mol/kg approximately 1 osmol/kg), to 4.5-fold of that in the control. The hairy roots showed strong tolerance to hyperosmotic stress, retaining a stable or higher dry weight of roots at osmolality up to 500 mmol/kg. Most remarkably, the combined use of sorbitol (50 g/l) and YE (100 mg/l) increased the TT content 10-fold (1481.6 versus 146.4 microg/g dry root) and the volumetric tanshinone yield 9-fold (16.3 versus 1.77 mg/l) compared with the control. The results suggest that the combined use of hyperosmotic stress and a biotic elicitor can effectively enhance secondary metabolite production in hairy-root cultures.

Development and application of medicinal plant tissue cultures for production of drugs and herbal medicinals in China.

In the search for new drugs and natural remedies, medicinal plants or herbs used in folk and traditional medicines are promising candidates. For the naturally rare and slowly growing plant species, plant tissue culture in bioreactors provides a cost-effective, sustainable and well-controlled means for mass production of the active principles of medicinal plants, and enables fuller utilization of their biosynthetic capacity. Recognizing that natural resources and agricultural land in China are limited,many Chinese research groups have engaged in the development of plant tissue culture techniques and processes for the cultivation and rapid propagation of medicinal plants, and for the biosynthesis and biotransformation of phytomedicines. This review primarily aims to provide a comprehensive summary of the major achievements in this and related research areas in China over the last three decades, but also to identify the difficulties and predict future trends in developing plant tissue culture biotechnology for the manufacture of bioactive natural products.

[Synergistic effects of biotic and abiotic elicitors on the production of tanshinones in Salvia miltiorrhiza hairy root culture].

OBJECTIVE: To investigate the synergistic effects of a biotic elicitor yeast extract and different abiotic elicitors (Ag+, Co2+ and alpha-amino isobutyric acid) on the production of tanshinones in Salvia miltiorrhiza hairy root. METHOD: Different elicitors and their combinations were added to S. miltiorrhiza hairy root culture and the contents of three major tanshinones (crypotanshinone, tanshinone I and tanshinone II A) were analyzed by HPLC. RESULT: The combinations of yeast extract with different abiotic elicitors had notable synergistic effects on the tanshinone I and tanshinone II A production but not on crypotanshinone. The combination of yeast extract and Ag+ (300 micromol x L(-1)) yielded the highest tanshinone I content, which was nearly 14-fold of the control, and the synergistic elicitation coefficient was 3.0. The combination of yeast extract and Co2+ (100 micromol L(-1)) led to the highest tanshinone IIA content, which was about 14.5-fold of the control, and the synergistic elicitation coefficient was 2.1. Only yeast extract combined with alpha-amino isobutyric acid (200 micromol x L(-1)) increased the crypotanshinone content more effectively than single elicitors. The highest crypotanshinone content was 1.28 mg x g(-1), about 30-fold of the control with a synergistic elicitation coefficient of 1.3. CONCLUSION: The elicitation by the combination of a biotic elicitor and an abiotic elicitor can generate a synergistic effect, which is more effective than single elicitors to promote secondary metabolite production in plant tissue cultures.