Distinction of water-soluble constituents between natural and cultured Cordyceps by capillary electrophoresis

Cordyceps is an expensive traditional Chinese medicine, which has anti-tumor activity and significant effects on the immune system. In Southeast Asia, Cordyceps is commonly sold in capsule form as a health food product. Most of these products are derived from cultured Cordyceps mycelia. Because of the price difference, some manufacturers claim their products are from natural Cordyceps. In order to distinguish among various types of Cordyceps in the market, the profiles of water-soluble constituents derived from different sources of Cordyceps were determined by capillary electrophoresis (CE). Both natural and cultured Cordyceps showed three peak clusters migrated at 5–7, 9–11 and 12–13 min, and the height and resolution of these peak clusters were rather distinct. Peak cluster at 9–11 min was identified as adenosine, guanosine and uridine, and shared a similarity between natural and cultured products. In contrast, the peak cluster at 5–7 min was characteristic of natural Cordyceps, regardless of hosts and sources. By using the peak characteristics of CE profiles of different Cordyceps samples, hierarchical clustering analysis was performed. The result shows that those samples of natural Cordyceps were grouped together distinct from the cultured and commercial products. Thus, the CE profiles could serve as fingerprints for the quality control of Cordyceps.     

Catalytic characteristics of a sn-1(3) regioselective lipase from Cordyceps militaris

A total of 39 agricultural products were screened for natural sources of lipases with distinctive positional specificity. Based on this, Cordyceps militaris lipase (CML) was selected and subsequently purified by sequential chromatography involving anion-exchange, hydrophobic-interaction, and gel-permeation columns. As a result of the overall purification procedure, a remarkable increase in the specific activity of the CML (4.733 U/mg protein) was achieved, with a yield of 2.47% (purification fold of 94.54). The purified CML has a monomeric structure with a molecular mass of approximately 62 kDa. It was further identified as a putative extracellular lipase from C. militaris by the partial sequence analysis using ESI-Q-TOF MS. In a kinetic study of the CML-catalyzed hydrolysis, the values of V_max, K_m, and k_cat were determined to be 4.86 μmol·min⁻¹·mg⁻¹, 0.07 mM, and 0.29 min⁻¹, respectively. In particular, the relatively low K_m value indicated that CML has a high affinity for its substrate. With regard to positional specificity, CML selectively cleaved triolein at the sn-1 or 3 positions of glycerol backbone, releasing 1,2(2,3)-diolein as the major products. Therefore, CML can be considered a distinctive biocatalyst with sn-1(3) regioselectivity. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2744, 2019.     

Morphological and phylogenetic studies onCordyceps sinensis distributed in southwestern China

Cordyceps is one of the target genera for modern mycological studies. Among themCordyceps sinensis is the most famous but poorly defined species because the fungus is endemic in districted regions of east Eurasia. We have explored the various growing regions and habitats where the fungus grows in the wild. We also examined authentic cultures for the species. We analyzed the sequences of ITS1, 2 and 5.8 S rDNA regions ofC. sinensis materials collected from 11 localities of southwestern China. Phylogenetic analyses were performed with these sequences and with additional sequences obtained from GenBank. All sequences formed a single cluster, which comprised two subgroups. Our results strongly suggested that intraspecific variation was rather small and that some species that are morphologically similar toC. sinensis but with different names might be synonymous withC. sinensis. The difference in the pharmaceutical activity among these collectedC. sinensis from different regions will be studied in the future.     

Bioconversion of Ginsenoside Rf into Its Hydrated Derivative with Elevated Anti-inflammatory Effect by a Highly Specific Biocatalytic System of Cordyceps Sinensis

The presence of 25-OH moiety has been proved to enhance the bioactivity of dammarane saponins in many cases. However, such modification by previous strategies had compromised yield and purity of target products. Herein ginsenoside Rf was specifically transformed into 25-OH-(20S)-Rf with a conversion rate of 88.03 % by a Cordyceps Sinensis-mediated biocatalytic system. The formulation of 25-OH-(20S)-Rf was calculated by HRMS, whilst its structure was validated by ¹H-NMR, ¹³C-NMR, HSQC, and HMBC analysis. Time-course experiments unveiled straightforward hydration of the double bond on Rf with undetectable side reactions and maximum production of 25-OH-(20S)-Rf on the 6^th day, which collectively suggested the suitable timing of harvesting this target compound. In vitro bioassay of (20S)-Rf and 25-OH-(20S)-Rf against lipopolysaccharide-induced macrophages indicated a significant boost of anti-inflammatory effects after the C24−C25 double bond was hydrated. Therefore, the biocatalytic system in this article could be leveraged to deal with macrophage-mediated inflammation under defined circumstances.