Allimacrosides A-E, new steroidal glycosides from Allium macrostemon Bunge

Antioxidant activity of spirostanol saponins from Allii Macrostemonis Bulbus and their contents in different origins and processed products

Allii Macrostemonis Bulbus (AMB), a traditional Chinese edible and medicinal plant, is considered beneficial to health. In this study, we isolated and purified nine steroidal saponins (compounds 1-9) from AMB. Their structures were characterized using physicochemical properties, HR-ESI-MS, 1D and 2D NMR spectroscopy. Among these compounds, compounds 1-5 were newly discovered named macrostemonoside U-Y, respectively. We assessed the in vitro antioxidant properties of the nine steroidal saponins through free radical scavenging and reducing power assays. This provides options for developing natural antioxidants. Additionally, an HPLC-ELSD quantitative analysis method was developed for the nine saponins in 12 batches of AMB from different origins and processing methods. The results showed that the contents of the nine steroidal saponins in AMB varied greatly among different growing environments and processing methods.

Chemical Constituents, Biological Activities, and Proposed Biosynthetic Pathways of Steroidal Saponins from Healthy Nutritious Vegetable-Allium

Allium is a common functional vegetable with edible and medicinal value. Allium plants have a special spicy taste, so they are often used as food and seasoning in people's diets. As a functional food, Allium also has abundant biological activities, some of which are used as drugs to treat diseases. By consuming Allium on a daily basis, people can receive active compounds of natural origin, thereby improving their health status and reducing the likelihood of disease. Steroidal saponins are important secondary metabolites of Allium, which are formed by the steroidal aglycone group and sugar. Steroidal saponins have various physiological activities, such as hypoglycemic, antiplatelet aggregation, anti-inflammatory, antitumor, antimicrobial, and enzyme activity inhibition, which is one of the key reasons why Allium has such significant health benefits. The structural diversity and rich biological activities of steroidal saponins make Allium important plants for both food and medicine. In this paper, the chemical structures, biological activities, and structure-activity relationships of steroidal saponins isolated from Allium are reviewed, and the biosynthetic pathways of some key compounds are proposed as well, to provide a molecular reference basis based on secondary metabolites for the health value of Allium.

Allii Macrostemonis Bulbus: A Comprehensive Review of Ethnopharmacology, Phytochemistry and Pharmacology

The dried bulbs of Allii Macrostemonis Bulbus (AMB) are called “薤白” in China and are mainly distributed in Asia. The plant species included in the 2020 Edition of the Chinese Pharmacopoeia (ChP) are Allium macrostemon Bunge (called xiaogensuan in Chinese, A. macrostemon) and Allium chinense G. Don (called xie in Chinese, A. chinense), respectively. In the traditional Chinese medicine (TCM) theoretical system, AMB is warm in nature, acrid-bitter taste, and attributive to the heart, lung, stomach, large intestine meridian. AMB has the function of activating Yang and removing stasis, regulating Qi and eliminating stagnation. Modern pharmacological studies have shown that AMB has anti-platelet aggregation, hypolipidemic, anti-atherosclerotic, cardiomyocyte, vascular endothelial cell protection, anti-cancer, anti-bacterial, anti-asthmatic, and anti-oxidant effects. In some Asian countries, AMB is often used to treat coronary heart disease (CHD), angina pectoris (AP), asthma, and diarrhea. This review collates the botanical background, ethnopharmacology, phytochemistry, pharmacological activities, quality control, and toxicological studies of AMB, and provides an outlook on the current research deficiencies and future research priorities of AMB, intending to provide ideas for future research directions and commercial development.

Five new spirosterol saponins from Allii Macrostemonis Bulbus

Five new spirostanol saponins (1-5) and seven known compounds (6-12) were isolated from the n-butanol fraction of 75% ethanol extract of Allii Macrostemonis Bulbus. The identification and structural elucidation of all the isolates were performed through extensive 1D and 2D NMR experiments, HR-ESI-MS data analysis and comparisons with literature values. Antioxidant evaluation showed that compounds 6-11 exhibited certain scavenging effects on ABTS radical, where compounds 6, 7 and 11 had IC₅₀ values of 0.208, 0.057 and 0.014 mg·mL^-1, respectively.

Structure, Bioactivity and Analytical Methods for the Determination of Yucca Saponins

Yucca is one of the main sources of steroidal saponins, hence different extracts are commercialized for use as surfactant additives by beverage, animal feed, cosmetics or agricultural products. For a deeper understanding of the potential of the saponins that can be found in this genus, an exhaustive review of the structural characteristics, bioactivities and analytical methods that can be used with these compounds has been carried out, since there are no recent reviews on the matter. Thus, a total of 108 saponins from eight species of the genus Yucca have been described. Out of these, the bioactivity of 68 saponins derived from the isolation of Yucca or other genera has been evaluated. Regarding the evaluation and quality control of the saponins from this genus LC-MS technique is the most often used. Nevertheless, the development of methods for their routine analysis in commercial preparations are needed. Moreover, most of the studies found in the literature have been carried out on Y. schidigera extract, since is the most often used for commercial purposes. Only eight of the 50 species that belong to this genus have been studied, which clearly indicates that the identification of saponins present in Yucca genus is still an unresolved question.

Iridoid Glycosides from the Twigs of Sambucus williamsii var. coreana and Their Biological Activities

Six new iridoid glycosides, sambucusides A-F (1-6), and two known derivatives (7 and 8) were isolated from a methanol extract of the twigs of Sambucus williamsii var. coreana. Their chemical structures were elucidated by spectroscopic methods, including NMR (¹H and ¹³C NMR, ¹H-¹H COSY, HMQC, HMBC, and NOESY) and HRMS. All isolated compounds (1-8) were evaluated for their antiproliferative activities against four human cancer cell lines (A549, SK-OV-3, SK-MEL-2, and Bt549). Their effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-activated BV-2 cells and their neuroprotective effects through induction of nerve growth factor (NGF) in C6 glioma cells were also examined. Compounds 2, 3, and 5 showed cytotoxic effects (IC₅₀ 1.3-8.7 μM) against the SK-MEL-2 and Bt549 cell lines and inhibitory effects on NO production (IC₅₀ of 0.9, 1.3, and 1.2 μM, respectively). Compounds 2, 4, and 8 exhibited NGF-releasing effects (147.0 ± 5.8%, 158.7 ± 5.2%, and 152.6 ± 7.3%, respectively).