Optimization of the Ultrasonic-Assisted Extraction Technology of Steroidal Saponins from Polygonatum kingianum Collett & Hemsl and Evaluating Its Quality Planted in Different Areas

Polygonati Rhizoma: A review on the extraction, purification, structural characterization, biosynthesis of the main secondary metabolites and anti-aging effects

ETHNOPHARMACOLOGICAL RELEVANCE

Polygonati Rhizome (PR) is a plant that is extensively widespread in the temperate zones of the Northern Hemisphere. It is a member of the Polygonatum family of Asparagaceae. PR exhibits diverse pharmacological effects and finds applications in ethnopharmacology, serving as a potent tonic for more than two millennia. PR's compounds endow it with various pharmacological properties, including anti-aging, antioxidant, anti-fatigue, anti-inflammatory, and sleep-enhancing effects, as well as therapeutic potential for osteoporosis and age-related diseases.

AIM OF THE STUDY

This review seeks to offer a thorough overview of the processing, purification, extraction, structural characterization, and biosynthesis pathways of PR. Furthermore, it delves into the anti-aging mechanism of PR, using organ protection as an entry point.

MATERIALS AND METHODS

Information on PR was obtained from scientific databases (Google Scholar, Web of Science, ScienceDirect, SciFinder, PubMed, CNKI) and books, doctoral theses, and master's dissertations.

RESULTS

In this investigation, 49 polysaccharides were extracted from PR, and the impact of various processing, extraction, and purification techniques on the structure and activity of these polysaccharides was evaluated. Additionally, 163 saponins and 46 flavonoids were identified, and three key biosynthesis pathways of secondary metabolites were outlined. Notably, PR and Polygonat Rhizomai polysaccharides (PRP) exhibit remarkable protective effects against age-induced injuries to the brain, liver, kidney, intestine, heart, and vessels, thereby promoting longevity and ameliorating the aging process.

CONCLUSIONS

PR, a culinary and therapeutic herb, is rich in active components and pharmacological activities. Based on this review, PR plays a meaningful role in lifespan extension and anti-aging, which can be attributed to PRP. Future research should delve deeper into the structural aspects of PRP that underlie its anti-aging effects and explore potential synergistic interactions with other compounds. Moreover, exploring the potential applications of PR in functional foods and pharmaceutical formulations is recommended to advance the development of industries and resources focused on healthy aging.

Activities of polysaccharide fractions from corn silk: Hemostatic, immune, and anti-lung cancer potentials

Corn silk is the stigma and style of corn and is rich in polysaccharides. Despite the extensive research on its polysaccharides, the hemostatic characteristics of effective parts and the related activities remain insufficiently explored. Corn silk polysaccharide (CSP) was extracted with hot water and purified using a diethylaminoethyl cellulose membrane. Then, it was separated with sephadex G-150 to obtain five fractions. These fractions were investigated for their potential in hemostasis, antioxidant, immune response, and anti-lung cancer activities. CSP-2, CSP-3, and CSP-4 significantly affected the coagulation indicators activated partial thromboplastin time (APTT) and thrombin time (TT) at 125-500 μg/mL. Corn silk flavonoids and saponins at 32.25 μg/mL significantly prolonged APTT, TT, and prothrombin time (PT). CSP-2, with potent antioxidant ability, approaches Vitamin C. At 25 μg/mL, CSPs nearly reached the phagocytosis of neutral red of lipopolysaccharides. The five fractions promoted the proliferation of RAW264.7 cells at 25-800 μg/mL and stimulated NO secretion at 25-100 μg/mL. CSP-2 also showed an 86 % inhibition rate effect on A549 at 200 μg/mL. These results indicate that CSP not only has hemostatic effects but also has immune and anti-lung cancer activities. Thus, it is a potential candidate compound with immune activity for managing bleeding in cancer.

Saponins of North Atlantic Sea Cucumber: Chemistry, Health Benefits, and Future Prospectives

Frondosides are the major saponins (triterpene glycosides) of the North Atlantic sea cucumber (Cucumaria frondosa). Frondosides possess amphiphilic characteristics due to the presence of various hydrophilic sugar moieties and hydrophobic genin (sapogenin). Saponins are abundant in holothurians, including in sea cucumbers that are widely distributed across the northern part of the Atlantic Ocean. Over 300 triterpene glycosides have been isolated, identified, and categorized from many species of sea cucumbers. Furthermore, specific saponins from sea cucumbers are broadly classified on the basis of the fron-dosides that have been widely studied. Recent studies have shown that frondoside-containing extracts from C. frondosa exhibit anticancer, anti-obesity, anti-hyperuricemic, anticoagulant, antioxidant, antimicrobial, antiangiogenic, antithrombotic, anti-inflammatory, antitumor, and immunomodulatory activities. However, the exact mechanism(s) of action of biological activities of frondosides is not clearly understood. The function of some frondosides as chemical defense molecules need to be understood. Therefore, this review discusses the different frondosides of C. frondosa and their potential therapeutic activities in relation to the postulated mechanism(s) of action. In addition, recent advances in emerging extraction techniques of frondosides and other saponins and future perspectives are discussed.

A Method for Improving Microbial Conversion of Diosgenin and Separation and Identification of the Product

Diosgenin, a hydrolysis product from Dioscorea plants, can be used as a precursor of steroid drugs (e.g., progesterone, testosterone, and glucocorticoid). However, traditional acid hydrolysis production wastes water and causes severe environmental pollution. The extraction of diosgenin through microbial transformation is the most green and environmentally friendly method at present. In order to improve the efficiency of the extraction of diosgenin through microbial transformation, we proposed a new method of strain mutagenesis. After mutagenesis, the response surface methodology was used to optimize the solid-state fermentation medium, thereby improving the diosgenin yield. We found that the optimal formulation was 5.5% sucrose, 0.6% NH4H2PO4, and 26.6% wheat bran. The final extraction rate of diosgenin reached 0.439% (the value of diosgenin per g. of starting plant dry material). Compared with 0.338% before optimization, it had increased 1.29 times. Furthermore, two other compounds were isolated from the fermentation products. These were identified as diosgenone (C27H41O3) and yuccagenone (C27H42O3). Traditional diosgenone is obtained through the oxidation of diosgenin with oxalic acid, but the method in this study is directly obtained from Dioscorea rhizome powder. The price of Dioscorea rhizome powder is much lower than diosgenin, thus greatly reducing the cost of obtaining diosgenone. This method provides a basis for subsequent research on other pharmacological compounds.

Saponins as Natural Emulsifiers for Nanoemulsions

The awareness of sustainability approaches has focused attention on replacing synthetic emulsifiers with natural alternatives when formulating nanoemulsions. In this context, a comprehensive review of the different types of saponins being successfully used to form and stabilize nanoemulsions is presented, highlighting the most common natural sources and biosynthetic routes. Processes for their extraction and purification are also reviewed altogether with the recent advances for their characterization. Concerning the preparation of the nanoemulsions containing saponins, the focus has been initially given to screening methods, lipid phase used, and production procedures, but their characterization and delivery systems explored are also discussed. Most experimental outcomes showed that the saponins present high performance, but the challenges associated with the saponins' broader application, mainly the standardization for industrial use, are identified. Future perspectives report, among others, the emerging biotechnological processes and the use of byproducts in a circular economy context.