Endophytic fungi of Lycium barbarum: isolation, determination, bioactivity and separation of compounds.

Lycium barbarum is widely distributed in China and used as a traditional Chinese medicine herb to treat dizziness, abdominal pain, dry cough, headache and fatigue. Several studies have examined the endophytes of L. barbarum from northwest China; however, few have focused on that from eastern China. The objective of this study was to isolate and determine the endophytic fungi of L. barbarum from Shandong province, as well as to obtain and identify active secondary metabolites from the endophytes. In this study, 17 endophytic fungi were isolated from L. barbarum and denoted as GQ-1 to GQ-17, respectively. These fungi were further classified into ten genera based on the morphological and ITS identification. The crude extracts of these fungi were obtained by using liquid fermentation and EtOAc extraction, and their antibacterial, cytotoxic, and antioxidant activities were evaluated. The results showed that GQ-6 and GQ-16 exhibited high inhibitory activity; GQ-6 and GQ-9 showed high cytotoxic activity and GQ-5 exhibited high scavenging capability for DPPH free radicals. Additionally, Cladosporium sp. GQ-6 was used to investigate the secondary metabolites. The crude extracts were purified by using column chromatography, reverse column, and liquid chromatography, and four monomeric compounds were identified, including two known compounds (α-acetylorcinol (1) and cladosporester B (2)) and two new compounds (cladosporacid F (3) and cladosporester D (4)). The anti-fungal and antibacterial activities of these compounds were confirmed, but no cytotoxic activity was observed. In conclusion, endophytic fungi of L. barbarum from eastern China can serve as a potential source of active natural products with antibacterial and antioxidant properties.

Antimicrobial Potential of Endophytic Fungi From Artemisia argyi and Bioactive Metabolites From Diaporthe sp. AC1.

Endophytic fungi of medicinal plants are important sources of active natural products. In this study, 26 fungi were isolated from Artemisia argyi, which were belonging to eight genera, namely, Alternaria, Fusarium, Chaetomium, Phoma, Diaporthe, Trichoderma, Gibberella, and Colletotrichum. The antimicrobial activities of all fungal extracts were tested by using the cup-plate method against Staphylococcus aureus, Salmonella enteritidis, and Fusarium graminearum. The results demonstrated that 25 extracts (96%) exhibited inhibitory activity against at least one of the tested pathogenic microorganisms. The strain Diaporthe sp. AC1, which showed good antimicrobial activity and high yield of crude extract from fermentation, was selected for the study of secondary metabolites. The crude extract of strain AC1 was purified by silica gel column chromatography, Sephadex LH-20 gel column chromatography, and HPLC, and finally, a new compound phomopsolide G (1), together with three known phomopsolides (2-4) and four other known compounds (5-8), was obtained. The structures of the compounds were elucidated by NMR and/or HR-MS spectroscopy. Microdilution method and MTT colorimetry were used to determine the bioactivity of the compounds. The study demonstrated that the new compound 1 had moderate antifungal activity against F. graminearum, Fusarium moniliforme, and Botrytis cinerea and weak antibacterial activity against Staphylococcus aureus. Compound 1 also showed weak cytotoxicity against HepG2, A549, and MDA-MB-231, with IC50 values of 89.91, 107.65, and 53.97 µM. Additionally, other compounds also exhibited antimicrobial and/or cytotoxic activities. The findings provided the basis for searching drug and agricultural lead compounds from A. argyi-associated fungi resources.

A novel nanobody and mimotope based immunoassay for rapid analysis of aflatoxin B1.

Mimotopes could replace mycotoxins and their conjugates to develop immunoassay methods. The mimotopes obtained by phage display technology were mainly using monoclonal antibodies or polyclonal antibodies as targets. However, the mimotope of recombinant antibody has not been selected and applied to immunoassay for mycotoxin. The purpose of this study was to prove that an immunoassay for mycotoxin could be developed based on both recombinant antibody and its mimotope. Using aflatoxin B1 (AFB1) as a model system, mimotopes of an aflatoxin nanobody Nb28 were screened by phage display. A rapid magnetic beads-based directed competitive ELISA (MB-dcELISA) was developed utilizing Nb28 and its mimotope ME17. The 50% inhibitory concentration and the detection limit of the MB-dcELISA were 0.75 and 0.13 ng/mL, respectively, with a linear range of 0.24-2.21 ng/mL. Further validation study indicated good recovery (84.2-116.2%) with low coefficient of variable (2.2%-15.9%) in spiked corn, rice, peanut, feedstuff, corn germ oil and peanut oil samples. The developed immunoassay based on nanobody and mimotope provides a new strategy for the monitoring of AFB1 and other toxic small molecular weight compounds.

[Determination of phenols and triterpenoid saponins in stems of Sargentodoxa cuneata].

The methods to determine the total phenols, total saponins, and marker constituents salidroside, chlorogenic acid and 3, 4-dihydroxy-phenylethyl-ß-D-glucopyranoside in the samples of Sargentodoxae Caulis were established to provide the evidence for the improvement and revision of the quality standard of the crude material recorded in the Chinese Pharmacopoeia (2015 Edition). The content of total phenols was determined by ultraviolet spectrophotometry, using gallic acid as a reference substance. The content of total saponins was determined by ultraviolet spectrophotometry, using 3-O-[ß-D-xylopyranosyl-(1-2)-O-ß-D-glucuronopyranosyl]-28-O-[ß-D-glucopyranosyl] asiatic acid as a reference substance. The contents of salidroside, chlorogenic acid and 3,4-dihydroxy-phenylethyl-ß-D-glucopyranoside were detected by HPLC. The linear ranges were 1.01-7.04 mg x L(-1) for total phenols, 37.7-201 µg for total saponins, 0.025 8-1.55 µg for salidroside, 0.076 2-5.44 µg for chlorogenic acid, and 0.064 9-3.47 µg for 3,4-dihydroxy-phenylethyl-ßP-D-glucopyranoside, respectively. Their average recoveries were 99.12%, 99.11% 105.5%, 99.08%, and 101.6%, respectively. The contents of total phenols and total saponins were 3. 04% -11. 9% and 0. 87% -3. 63%. The contents of salidroside, chlorogenic acid and 3,4-dihydroxy-phenylethyl-ß-D-glucopyranoside fluctuated from 0.018% to 0. 572%, from 0.041% to 1.75% and from 0.035% to 1.32%. The established methods were reproducible, and they could be used for the quality control of Sargentodoxae Caulis. The present investigation suggested that total phenols, salidroside, and chlorogenic acid should be recorded in the quality standard of Sargentodoxae Caulis and their contents should not be less than 6.8% for total phenols, 0.040% for salidroside, and 0.21% for chlorogenic acid.

[Study on quality standard of Sophora flavescens root extract].

As a part of the project for the Chinese Pharmacopoeia (2015 edition), the quality standard of Sophora flavescens root extract was investigated and established. According to the methods described in the Appendix of Chinese Pharmacopoeia (2010 edition), the water and ash inspections were carried out. The marker components trifolirhizin, sophoraflavanone G, oxymatrine and oxysophocarpine in the samples were identified by qualitative TLC. The determination of oxymatrine, matrine, oxysophocarpine and sophocarpine was conducted by HPLC and the total flavonoids were measured by ultraviolet spectrophotometry, using sophoraflavanone G as reference substance. The results indicated the spots on the plate were clear with good resolution and the contents of oxymatrine, matrine, oxysophocarpine and sophocarpine in the 13 batches of the samples were 3.87% - 11.1%, 0.970% - 4.33%, 1.30% - 2.59% and 0.260% - 1.14%, respectively. The total flavoids in the 13 batches of the samples were 3.88% - 7.93%. In the study, the validated methods were reproducible and the established quality standard was feasible, which could be used for the quality control of S. flavescens root extract and related preparations.

[Rapid determination of the multi-marker ingredients in Heterosmilacis Japonicae Rhizoma and Sophorae Flavescentis Radix with near-infrared diffused reflection spectroscopy].

A rapid NIRS method for determination of macrozamin in Heterosmilacis japonicae rhizoma (HJR), and the total content of oxymatrine and matrine (OMT + MT) as well as the total content of oxysophocarpine and sophocarpine (OSC + SC) in sophorae flavescens radix (SFR) was developed to explore the application feasibility of NIRS for the quality assurance system of Chinese patent drugs. The contents of macrozamin in HJR samples, and OMT + MT and OSC + SC in SFR samples were determined by HPLC as reference values. The NIR spectra of the samples were measured in a diffused reflection mode. The different characteristic wavebands and pretreatment methods were optimized. The quantitative calibration models between the NIR spectra and the content reference values of marker components in HJR and SFR samples, were established with partial least square method, and further optimized through the cross validation and external validation. The contents of macrozamin in 88 batches of HJR samples were over the range of 0.36-12.88 mg · g(-1). The total contents of OMT + MT and OSC + SC in 75 batches of SFR samples were over the range of 8.87-66.31 and 2.30-15.11 mg · g(-1), respectively. The performance of the final models for macrozamin, OMT + MT and OSC + SC was evaluated well according to correlation coefficients (r), root mean square error of cross-validation (RMSECV) and root mean square error of prediction (RMSEP). The R2 values of the cross-validation for macrozamin, OMT + MT and OSC + SC were 0.9025, 0.9491 and 0.9137, and those of RMSECV were 0.961, 2.45 and 0.724 mg · g(-1) respectively. The R2 values of external validation for the three models were 0.9817, 0.9826 and 0.9609, and those of RMSEP were 0.693, 2.27 and 0.658 mg · g(-1), respectively. This is the first report on rapid determination of macrozamin in Heterosmilacis japonicae rhizoma, and oxymatrine, matrine, oxysophocarpine and sophocarpine in sophorae flavescens radix by NIRS method. The presented method can fulfill the requirement of rapid acquirement of chemical information of raw medicinal materials prior the manufacturing of compound Kushen injection.