Features in the NMR spectra of the aglycones of Agave spp. saponins. HMBC method for aglycone identification (HMAI)

Dereplication of Bioactive Agave Saponin Fractions: The Hidden Saponins

The good phytotoxicity and selectivity against weeds versus tomato or cress make saponin-rich fractions from Agave macroacantha, A. colorata, A. parryi, and A. parrasana attractive candidates as bioherbicides. The saponin contents have only previously been reported for A. macroacantha, and as a consequence, simultaneous dereplication has been performed on saponin-rich fractions from the other plants by mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. This strategy enables the identification of a total of 26 saponins, 14 of which have been described previously and 12 of which are proposed as new saponins. They include isomers and a new sugar chain with a β-d-apiofuranose unit. The method is corroborated by the isolation of eight dereplicated saponins from A. colorata.

Steroidal Saponins with Plant Growth Stimulation Effects; Yucca schidigera as a Commercial Source

Plant growth-stimulation bioactivity of triterpenoid saponins is well known, especially for oleanane-type compounds. Nevertheless, a few phytotoxicity bioassays performed on some steroidal saponins have shown hormesis profiles and growth stimulation on Lactuca sativa roots. The focus of the work described here was on the use of the wheat coleoptile bioassay to evaluate plant growth stimulation, and on the search for a commercially available source of active saponins by bio-guided fractionation strategy. Selected saponins were tested and a cluster analysis showed that those saponins with a sugar chain of more than five units had a hormesis profile, while saponins with growth enhancement had fewer sugar residues. Two saponins showed similar activity to the positive control, namely the phytohormone indole-3-butyric acid (IBA). As a potential source of these metabolites, a commercial extract of Yucca schidigera used as a fertilizer was selected. Bio-guided fractionation led to the identification of two fractions of defined composition and these showed stimulation values similar to the positive control. It was observed that the presence of a carbonyl group at C-12 on the aglycone skeleton led to improved activity. A saponin-rich fraction from Y. schidigera could be proposed to enhance crop quality and production.

Phytochemical and pharmacological studies on Solanum lyratum: a review

Solanum lyratum is one of the temperate plants, broadly distributed in Korea, China, Japan, India, and South-East Asia and well-documented in those oriental ethnic medicine systems for curing cancers, jaundice, edema, gonorrhea, cholecystitis, phlogosis, rheumatoid arthritis, etc. This review systematically summarized the research progress on S. lyratum respecting the botany, traditional uses, phytochemistry, pharmacology, and toxicology to increase people's in-depth understanding of this plant, by data retrieval in a series of online or off-line electronic databases as far as we can reach. Steroidal saponins and alkaloids, terpenoids, nitrogenous compounds, and flavonoid compounds are the main chemical constituents in S. lyratum. Among them, steroidal alkaloids and saponins are the major active ingredients ever found in S. lyratum, exerting activities of anti-cancer, anti-inflammation, anti-microbial, anti-allergy, and anti-oxidation in vivo or in vitro. As a result, S. lyratum has been frequently prescribed for the abovementioned therapeutic purposes, and there are substantial traditional and modern shreds of evidence of its use.

Potential Use of Agave Genus in Neuroinflammation Management

Agavaceae contains about 480 species, commonly used in the production of alcoholic beverages such as tequila and mezcal, making it a resource of economic and cultural importance. Uses of this plant rely mainly on the stem; other components such as the leaves are discarded, generating agro-industrial waste, despite being a source of bioactive and nutraceutical products. Reports show anti-inflammatory and anti-neuroinflammatory effects of these species, with flavonoids and saponins being mainly responsible. Neuroinflammation is a brain process that plays a key role in the pathogenesis of various neurodegenerative disorders and its effects contribute greatly to mortality and morbidity worldwide. This can be triggered by mechanisms such as glial reactions that lead to the release of inflammatory and oxidative molecules, causing damage to the CNS. Treatments do not cure chronic disease associated with inflammation; they only slow its progression, producing side effects that affect quality of life. Plant-based therapy is promising for treating these diseases. Pharmacological activities have been described for the Agavaceae family; however, their role in neuroinflammation has not been fully investigated, and represents an important target for study. This review synthesizes the existing literature on the biologically active compounds of Agave species that are related in some way to inflammation, which will allow us to propose a line of research with this genus on the forefront to orient experimental designs for treating neuroinflammation and associated diseases.

Dereplication of Bioactive Spirostane Saponins from Agave macroacantha

A dereplication strategy using UPLC-QTOF/MSE, the HMAI method, and NMR spectroscopy led to the identification of five main steroidal saponins (1-5), including three previously unknown compounds named macroacanthosides A-C (3-5), in a bioactive fraction of Agave macroacantha. The major saponins were isolated, and some of them together with the saponin-rich fraction were then evaluated for phytotoxicity on a standard target species, Lactuca sativa. The inhibition values exhibited by the pure compounds were confirmed to be in agreement with the phytotoxicity of the saponin-rich fraction, which suggests that the saponin fraction could be applied successfully as an agrochemical without undergoing any further costly and/or time-consuming purification processes. The NMR data of the pure compounds as well as of those corresponding to the same compounds in the fraction were comparable, which indicated that the main saponins could be identified by means of this replication workflow and that no standards are required.