A new polyketide glycoside from the rhizospheric Clonostachys rogersoniana associated with Panax notoginseng

Accumulation of antitumor polyketides by fermentation of Rubus delavayi Franch. with Clonostachys rogersoniana

The aim of this work is to explore the effects of herbal medicine on secondary metabolites of microorganisms during fermentation. Clonostachys rogersoniana was found to metabolize only small amounts of polyketide glycosides rogerson B and C on fresh potatoes, but after replacing the medium to the medicinal plant Rubus delavayi Franch., the type and content of the metabolized polyketones showed significant changes. The sugars and glycosides in R. delavayi are probably responsible for the changes in secondary metabolites. Six polyketide glycosides including a new metabolite, rogerson F, and two potential antitumor compounds, TMC-151C and TMC-151D, were isolated from the extract of R. delavayi fermented by C. rogersoniana. In addition, 13C labeling experiments were used to trace the biosynthesis process of these compounds. TMC-151C and TMC-151D showed significant cytotoxic activity against PANC-1, K562 and HCT116 cancer cells but had no obvious cytotoxic activity against BEAS-2B human normal lung epithelial cells. The yields of TMC-151C and TMC-151D reached 14.37 ± 1.52 g/kg and 1.98 ± 0.43 g/kg, respectively, after fermentation at 28 °C for 30 days. This is the first study to confirm that herbal medicine can induce microbes to metabolize active compounds. And the technology of fermenting medicinal materials can bring more economic value to medicinal plants.

Panax notoginseng-microbiota interactions: From plant cultivation to medicinal application

BACKGROUND

Microbiomes and their host plants are closely linked with each other; for example, the microbiome affects plant growth, fitness, nutrient uptake, stress tolerance and pathogen resistance, whereas the host plant supports the photosynthetically carbon-rich nutrition of the microbiome. The importance of the microbiome in plant‒soil ecosystems is unquestioned and has expanded to influence the medicinal application of some herbal plants via the gut microbiota.

PURPOSE

Herbal plant-microbiome interactions may provide novel knowledge to enhance the robustness of herbal plant crop performance and medicinal applications, which requires a systematic review and preceding discussion.

STUDY DESIGN AND METHODS

The interactions between Panax notoginseng and microorganisms (from soil to host) were reviewed from the literature. The terms "Panax notoginseng" and "microbiota" were used in combination with the keywords "microbiota/microbes", "bacteria/bacterium" or "fungi/fungus" or "endophyte", as well as our targeted bioactive phytochemicals, including saponins and ginsenosides.

RESULT

Our study focuses on the famous medicinal herb Panax notoginseng F. H. Chen and proposes that the microbiota is a crucial participant not only in the cultivation of this herbal plant but also in its medicinal application. We also summarize and discuss how these plant‒microbe co-associations shape the assembly of plant-related microbiomes and produce bioactive phytochemicals, as well as influence beneficial herbal traits, such as herbal plant health and pharmacology. In addition, we also highlight future directions.

CONCLUSION

The rhizosphere and endophytic microbiome of Panax notoginseng are indirectly or directly involved in plant health, biomass production, and the synthesis/biotransformation of plant secondary metabolites. Harnessing the microbiome to improve the quality of traditional Chinese medicine and improve the value of medicinal plants for human health is highly promising.

Metabolites from Clonostachys Fungi and Their Biological Activities

Clonostachys (teleomorph: Bionectria) fungi are well known to produce a variety of secondary metabolites with various biological activities to show their pharmaceutical and agrochemical applications. Up to now, at least 229 secondary metabolites, mainly including 84 nitrogen-containing metabolites, 85 polyketides, 40 terpenoids, and 20 other metabolites, have been reported. Many of these compounds exhibit biological activities, such as cytotoxic, antimicrobial, antileishmanial, antimalarial activities. This mini-review aims to summarize the diversity of the secondary metabolites as well as their occurrences in Clonostachys fungi and biological activities.

Applications of microbial co-cultures in polyketides production

Polyketides are a large group of natural biomolecules that are normally produced by bacteria, fungi and plants. These molecules have clinical importance due to their anti-cancer, anti-microbial, anti-oxidant and anti-inflammatory properties. Polyketides are biosynthesized from units of acyl-CoA by different polyketide synthases (PKSs), which display wide diversity of functional domains and mechanisms of action between fungi and bacteria. Co-culture of different micro-organisms can produce novel products distinctive from those produced during single cultures. This study compared the new polyketides produced in such co-culture systems and discusses aspects of the cultivation systems, product structures and identification techniques. Current results indicate that the formation of new polyketides may be the result of activation of previously silent PKSs genes induced during co-culture. This review indicated a potential way to produce pure therapeutic polyketides by microbial fermentation and a potential way to develop functional foods and agricultural products using co-co-culture of different micro-organisms. It also pointed out a new perspective for studies on the process of functional foods, especially those involving multiple micro-organisms.

Five New Phenolic Compounds with Antioxidant Activities from the Medicinal Insect Blaps rynchopetera

Five new phenolic compounds rynchopeterines A–E (1–5), in addition to thirteen known phenolics, were isolated from Blaps rynchopetera Fairmaire, a kind of medicinal insect utilized by the Yi Nationality in Yunnan Province of China. Their structures were established on the basis of extensive spectroscopic analyses (1D and 2D NMR, HR-MS, IR) along with calculated electronic circular dichroism method. Rynchopeterines A–E (1–4) exhibited significant antioxidant activities with IC₅₀ values of 7.67–12.3 μg/mL measured by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Besides, rynchopeterines B (2) and C (3) showed mild cytotoxicity against tumor cell Caco-2 and A549.

Fermentation of Illigera aromatica with Clonostachys rogersoniana producing novel cytotoxic menthane-type monoterpenoid dimers

Five novel menthane-type monoterpenoid dimers were isolated from non-fermented and Clonostachys rogersoniana fermented Illigera aromatica.