Advances in the synthesis and pharmacological activity of lupane-type triterpenoid saponins

Abstract

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.

Microbial transformations of betulinic and betulonic acids

“…The 13 C NMR data showed the best fit with two new CHOH groups at positions 7 and 15 with significant downfield shift as expected for a change from CH 2 to CHOH. The signals for neighboring 6,8,14, and 16 showed downfield shifts as expected. In proton NMR, the dd signal at 3.92 ppm can be assigned to the CHOH at position 15.…”

“…Betulinic acid (1c) derivatives were reported to have anticancer [1][2][3] and anti-HIV [4][5][6][7] activities. Several semisynthetic derivatives of betulinic acid 1c were found to improve oral bioavailability and pharmacological activity [5][6][7] where the synthetic modifications were mostly centered on addition of sugars or polar groups to the C-3 hydroxyl and C-28 carboxyl groups of betulinic acid 1c ( Fig. 1; Table 1).…”

Betulin Complex in γ-Cyclodextrin Derivatives: Properties and Antineoplasic Activities in In Vitro and In Vivo Tumor Models

“…Complexation with cyclodextrins is a well-known procedure to achieve this goal. Increasing the water solubility of these cholesterol-like triterpenoids by addition of hydrosoluble sections, such as sugar moieties at the C3 and/or C28 position of the lupane framework or synthesis of saponosides, led to potent pharmacological activity [19]. Natural and semisynthetic CDs have been involved in triterpene complexation [20] with good solubility but rather small stability constant values of the complexes, in which the best results were obtained with γ-CD derivatives.…”

Comparative Study on Phytochemical Composition and <i>In Vitro</i> Radical Scavenging Activity of Ethanolic Extracts of <i>Landolphia</i> <i>lanceolata</i> and Nutraceutical-C24/7

“…Alkaloids are anaesthetics, stimulants and anticancer agents [26]. Saponins have been reported to be cytotoxic and cholesterol lowering agents [27][28] Saponins possess antimicrobial, antiviral, antifungal, hypocholesterolaemic, immunostimulant, membrane permeabilising, insecticidal and molluscidal [29][30][31]. Tannins possess antioxidant, antimicrobial and antiviral, protein precipitating and iron-binding properties [30].…”