Recent Progress in the Synthesis of Naturally Occurring Triterpenoid Saponins (original) (raw)
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Advances in the synthesis and pharmacological activity of lupane-type triterpenoid saponins
Phytochemistry Reviews, 2010
Lupeol, betulin and betulinic acid are members of the so-called lupane-type triterpenoids. These natural products found worldwide in quite of lot of vegetables, fruits and plant species exhibit promising pharmacological activities including antiinflammatory, anti-HIV and antitumor activities. Nevertheless, the poor pharmacokinetic properties of these cholesterol-like triterpenoids hampered further pharmaceutical developments. The synthesis of lupanetype saponins, i.e., sugar-derived lupanes, seems to be a good avenue to improve both their water solubility and pharmacological activity. The aims of this review are twofold: first, to describe the biological activity of naturally occurring lupane-type saponins, and second, report the different methodologies employed for the elaboration of glycosidic linkages at the C-3 and/or C-28 positions on the lupane core. The synthesis of both natural and unnatural lupane-type saponins is discussed with an emphasis on molecules exhibiting relevant biological activities.
Naturally Occurring Triterpenoid Saponins
Chemistry & Biodiversity, 2010
Dedicated to the memory of Prof. (Mrs) Asima Chatterjee, University of Calcutta, for her devotion to set up a School for Natural Products Research in the Department of Chemistry Naturally occurring new triterpenoid saponins reported from mid-1996 to March, 2007 are reviewed including their physical constants and plant sources, and are compiled in Table 1. New saponins are arranged in Table 1 on the basis of the skeletal structures of their aglycones, e.g., oleanane type, ursane type, lupane type, hopane type, taraxastane type, cycloartane type, lanostane type, tirucallane type, dammarane type, cucurbitane type, and holostane type. The known triterpenoid saponins and prosapogenins of the new saponins, the biological and pharmacological activities of which were published during 1996-2007, are also reviewed together with their plant sources listed in Table 2 according to the skeletal structures of their aglycones in the same fashion as in Table 1. The plant and animal sources of both new and known bioactive triterpenoid saponins are collected in Table 3 in alphabetical order. The biological and pharmacological activities such as antiallergic, antiatherosclerosis and antiplatelet,
International Journal of Pharmacy and Pharmaceutical Sciences, 2015
Saponins are the potential bioactive compounds secreted by plants, endophytic fungi and marine organisms. Saponins are the glycosides containing non sugar portion, aglycone (sapogenin) attached to sugar moiety by glycosidic linkage. Depending on the chemical nature of aglycone, saponins are of triterpenoid and steroid saponins. The present review gives an overview of the biosynthesis pathway of triterpenoid saponins and mechanism of the biosynthesis. The review discusses the biomedical and pharmaceutical importance of triterpenoid saponins as they possess different activities including antimicrobial, haemolytic, hypolipidemic, immunomodulating and cytotoxic activities. The review also focuses on the mechanism of their action towards various activities.
New triterpenoid saponins from the roots of Saponaria officinalis
Natural product communications, 2013
Three new triterpenoid saponins (1-3), along with nine known saponins, were isolated from the roots of Saponaria officinalis L. Two of them: vaccaroside D (4) and dianchinenoside B (5) are known, but not previously reported for S. officinalis, and seven others: saponarioside C (6), D (7), F (8), G (9), I (10), K (11), and L (12) have been previously isolated from this plant. The structures of the new saponins were established as 3-O-beta-D-xylopyranosyl-16alpha-hydroxygypsogenic acid-28-O-[beta-D-glucopyranosyl-(1 -->6)-beta-D-glucopyranoside (1), 3-O-beta-D-xylopyranosyl-16alpha-hydroxygypsogenic acid-28-O-[beta-D-glucopyranosyl-(1-->3)]-[alpha-D-galactopyranosyl-(1-->6)-alpha-D-galactopyranosyl-(1-->6)-beta-D-glucopyranosyl-(1-->6)]-beta-D-glucopyranoside (2) and 3-O-beta-D-xylopyranosyl-gypsogenic acid-28-O-[beta-D-glucopyranosyl-(1-->3)]-[6-O-(3-hydroxy-3-methylglutaryl)-beta-D-glucopyranosyl-(1-->6)]-beta-D-glucopyranoside (3). Their structures were elucida...
Development of semisynthetic triterpenoid saponin derivatives with immune stimulating activity
Vaccine, 2000
Aldehyde-containing triterpene saponins have adjuvant properties, but only those from Quillaja saponaria Molina stimulate the production of cytotoxic T lymphocytes (CTL) against exogenous antigens. Quillaja saponins have two normonoterpene ester moieties, linked linearly to their fucosyl residue, that play a critical role in the stimulation of CTL. These ester moieties are also responsible for these saponins' instability and toxicity. Based on the structure±activity relationships for the dierent groups of Q. saponaria saponins, new semi-synthetic analogs were developed that have the adjuvanticity of quillaja saponins, yet with less toxicity and greater stability in aqueous solutions. The quillaja saponin analogs were prepared by replacing their hydrolytically unstable ester groups with another lipophilic chain linked by a stable amide bond on these saponins' glucuronic acid residue. One of these analogs, GPI-0100, is a dodecylamide saponin derivative that stimulates an antibody isotype pro®le that corresponds to a Th1 type immune response, as well as CTL production against exogenous antigens. 7
Saponins as cytotoxic agents: an update (2010–2021). Part II—Triterpene saponins
Phytochemistry Reviews
Saponins make up an important group of natural glycosidic compounds which are distinguished by triterpene or steroidal aglycone. Although widely distributed in terrestrial flora, especially higher plants, they can also be found in some marine organisms. Cytotoxic activity is one of the most frequently reported from a wide array of pharmacological activities known for these metabolites. The current review is an update of our previous paper—Saponins as cytotoxic agents (Podolak et al. Phytochem Rev 9:425–474, 2010), and covers studies that were since published (2010–2021). This part refers to triterpene saponins and complements the first, which was devoted solely to steroidal saponins (Sobolewska et al. Phytochem Rev 19:139–189, 2020). Cytotoxic activities in vitro and in vivo are presented with a main focus on structure-activity relationships and molecular mechanisms of action.
Synthesis and biological activity of new homolupanes and homolupane saponins
Tetrahedron, 2015
A concise synthesis of 28a-homolupane triterpenes and the corresponding saponins containing Dmannose, D-idose, D-arabinose, and L-rhamnose moieties was elaborated. The overall synthesis of the new triterpenes involved three linear steps starting from readily available 3-O-acetyl-betulinal: elongation of the carbon chain by Wittig reaction followed by enol ether hydrolysis and reduction (or oxidation) of the elongated aldehyde. Saponins were obtained by glycosylation of triterpenes with classical Schmidt donors. Cytotoxic activities of new lupane and homolupane compounds were evaluated in vitro. Several triterpenes and the corresponding saponins exhibited an interesting cytotoxic activity profile against human cancer cell lines. Influence of the side-chain structure and substituents on the cytotoxicity of betulin and homobetulin derivatives was investigated. These results open the way to the synthesis of various lupane-type triterpene and saponin derivatives as potential anticancer compounds.
N-triterpene Saponins in Cancer Therapy: a Review of Mode of Action
Revista Brasileira de Farmacognosia, 2020
Saponins are commonly found in higher plant parts, particularly in roots, tubers, leaves, and seeds, but N-triterpene saponins are rarely found in nature. Here, we focus on molecular structures and anticancer properties particularly in synergistic effects of toxicity, ion channel inhibitory, and opioid receptor modulatory effects of N-triterpene saponins.
Chemosystematically valuable triterpenoid saponins from Glandularia x hybrida
Phytochemistry, 2020
Phytochemical investigation of the ethanolic extract of Glandularia x hybrida roots resulted in the isolation and identification of five previously undescribed saponins, 3-O-β-ᴅ-xylopyranosyl-hederagenin-28-O-β-ᴅ-glucopyranosyl (1→2)-O-β-ᴅ-glucopyranosyl ester, 3-O-β-ᴅ-xylopyranosyl-hederagenin-28-O-β-ᴅ-glucopyranosyl (1→2)-[β-ᴅ-glucopyranosyl (1→6)]-β-ᴅ-glucopyranosyl ester, hederagenin-28-O-β-ᴅ-glucopyranosyl (1→2)-[β-ᴅ-glucopyranosyl (1→6)]-β-ᴅ-glucopyranosyl ester, 23-O-acetyl-3-O-β-ᴅ-xylopyranosyl-pomolic acid-28-O-β-ᴅ-glucopyranosyl ester, and 23-O-acetyl-pomolic acid-3-O-β-ᴅ-xylopyranoside, along with eleven structurally diverse compounds. The structural characterizations of the isolated compounds were determined using physical data, comprehensive 1D and 2D NMR spectral analysis, and HRESIMS. All isolated saponins are hederagenin or pomolic acid glycosides conjugated with differentiable sugar units bound to C-3 and/or C-28 of the aglycone through ether and/or ester glycosidic linkages, respectively. Structural diversity of these isolated secondary metabolites would have a great impact on the future chemosystematic studies of this plant. Four saponins, obtained in good yield were evaluated for their anti-inflammatory activities in a rat model using the carrageenan-induced paw edema protocol. Two of these exhibited significant anti-inflammatory activities demonstrated through inhibition of the paw edema by 64 and 60%.
Synthesis of a Highly Potent Antitumor Saponin OSW-1 and its Analogues
Phytochemistry Reviews, 2005
Twelve years ago a group of cholestane glycosides was isolated from the bulbs of Ornithogalum saundersiae, a species of the lily family without any medicinal folklore background. Similar glycosides were recently isolated from Galtonia candicans. The major component of the mixture of saponins, OSW-1, exhibited subnanomolar antineoplastic activity. While OSW-1 is exceptionally cytotoxic against various tumor cells, it shows little toxicity with normal human pulmonary cells. In this review article the synthetic efforts towards OSW-1 and related cholestane glycosides, as well as the preliminary results of the structure-activity relationship study are presented.