Recent progress on triterpenoid derivatives and their anticancer potential

Cancer poses a significant global public health challenge, with commonly used adjuvant or neoadjuvant chemotherapy often leading to adverse side effects and drug resistance. Therefore, advancing cancer treatment necessitates the ongoing development of novel anticancer agents with diverse structures and mechanisms of action. Natural products remain crucial in the process of drug discovery, serving as a primary source for pharmaceutical leads and therapeutic advancements. Triterpenoids are particularly compelling due to their complex structures and wide array of biological activities. Recent research has demonstrated that naturally occurring triterpenes and their derivatives have the potential to serve as promising candidates for new drug development. This review aims to comprehensively explore the anticancer properties of triterpenoids and their synthetic analogs, with a focus on recent advancements. Various aspects, such as synthesis, phytochemistry, and molecular simulation for structure-activity relationship analyses, are summarized. It is anticipated that triterpenoid derivatives will emerge as notable anticancer agents following further investigation into their mechanisms of action and in vivo studies.

Application of 18β-glycyrrhetinic acid in the structural modification of natural products: a review

18β-Glycyrrhetinic acid (GA) is an oleane-type pentacyclic triterpene saponin obtained from glycyrrhizic acid by removing 2 glucuronic acid groups. GA and its analogues are active substances of glycyrrhiza aicd, with similar structure and important pharmacological effects such as anti-inflammatory, anti-diabetes, anti-tumor and anti-fibrosis. Although GA combined compounds are in the clinical trial stages, its application potential is severely restricted by its low bioavailability, water solubility and membrane permeability. In this article, synthetic methods and structure-activity relationships (SARs) of GA derivatives from 2018 to present are reviewed based on pharmacological activity. It is hoped that this review can provide reference for the future development of potential GA preclinical candidate compounds, and furnish ideas for the development of pentacyclic triterpenoid lead compounds.

A review of typical biological activities of glycyrrhetinic acid and its derivatives

Glycyrrhetinic acid, a triterpenoid compound primarily sourced from licorice root, exhibits noteworthy biological attributes, including anti-inflammatory, anti-tumor, antibacterial, antiviral, and antioxidant effects. Despite these commendable effects, its further advancement and application, especially in clinical use, have been hindered by its limited druggability, including challenges such as low solubility and bioavailability. To enhance its biological activity and pharmaceutical efficacy, numerous research studies focus on the structural modification, associated biological activity data, and underlying mechanisms of glycyrrhetinic acid and its derivatives. This review endeavors to systematically compile and organize glycyrrhetinic acid derivatives that have demonstrated outstanding biological activities over the preceding decade, delineating their molecular structures, biological effects, underlying mechanisms, and future prospects for assisting researchers in finding and designing novel glycyrrhetinic acid derivatives, foster the exploration of structure-activity relationships, and aid in the screening of potential candidate compounds.

Evaluation of the Anticancer Activity and Mechanism Studies of Glycyrrhetic Acid Derivatives toward HeLa Cells

In this paper, a series of glycyrrhetic acid derivatives 3a–3f were synthesized via the esterification reaction. The cytotoxicity of these compounds against five tumor cells (SGC-7901, BEL-7402, A549, HeLa and B16) and normal LO2 cells was investigated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. The results showed that compound 3a exhibited high antiproliferative activity against HeLa cells (IC50 = 11.4 ± 0.2 μM). The anticancer activity was studied through apoptosis, cloning, and scratching; the levels of the intracellular ROS, GSH, and Ca2+; and the change in the mitochondrial membrane potential, cell cycle arrest and RNA sequencing. Furthermore, the effects of compound 3a on gene expression levels and metabolic pathways in HeLa cells were investigated via transcriptomics. The experimental results showed that this compound can block the cell cycle in the S phase and inhibit cell migration by downregulating Focal adhesion kinase (FAK) expression. Moreover, the compound can reduce the intracellular glutathione (GSH) content, increase the Ca2+ level and the intracellular ROS content, and induce a decrease in the mitochondrial membrane potential, further leading to cell death. In addition, it was also found that the mechanism of compounds inducing apoptosis was related to the regulation of the expression of mitochondria-related proteins B-cell lymphoma-2 (Bcl-2), Bcl-2-Associated X (Bax), and the activation of the caspase proteins. Taken together, this work provides a help for the development of glycyrrhetinic acid compounds as potential anticancer molecules.

Glycyrrhetinic acid: a promising scaffold for the discovery of anticancer agents

INTRODUCTION

Oleanane-type pentacyclic triterpenes named glycyrrhetinic acids (GAs) featuring a C-30 carboxylic acid group, are extracted from the licorice (Glycyrrhiza uralensis). Numerous biological properties of GA have been reported and have attracted researchers from all over the world in recent years due to the peculiar GA scaffold-based semisynthetic cytotoxic effects.

AREAS COVERED

This review represents the applications of semisynthetic derivatives of GA for the development of future cancer treatments. Included in the review are important structural features of the semisynthetic GAs crucial for cytotoxic effects.

EXPERT OPINION

Numerous semisynthetic GA derivatives illustrated excellent cytotoxic effects toward various cancer cells. Notably the C-₃(OH) at ring A along with C_30-CO₂H at ring E as vital structural features, make GA very appealing as a lead scaffold for medicinal chemistry, since these two groups permit the creation of further chemical diversity geared toward improved cytotoxic effects. Furthermore, numerous GA derivatives have been synthesized and indicate that compounds featuring cyanoenone moieties in ring A, or compounds having the amino group or nitrogen comprising heterocycles and hybrids thereof, illustrate more potent cytotoxicity. Furthermore, GA has a great capability to be conjugated with other anticancer molecules to synergistically enhance their combined cytotoxicity.

Antibacterial and antitumoral properties of 1,2,3-triazolo fused triterpenes and their mechanism of inhibiting the proliferation of HL-60 cells

Antimicrobial resistance and cancer are two important problems affecting human health. Actively developing novel antibiotics and anticancer medicines is a priority. Natural pentacyclic triterpenoids have attracted wide attention due to their significant biological activities. In this study, a series of 1,2,3-triazolo fused triterpenoids (betulin, oleanolic acid and ursolic acid) were functionalized on the A-ring by an in-house developed multi-component triazolization reaction. The compounds were investigated for antitumoral activity in twelve cancer cell lines and were also tested for antibacterial activity against four bacteria. In terms of anticancer effects, compounds 5b-f and 8a-d displayed strong cytotoxic activity in pancreatic adenocarcinoma (Capan-1), chronic myeloid leukemia (Hap-1), acute myeloid leukemia (HL-60), acute lymphoblastic leukemia (Jurkat) and non-Hodgkin lymphoma (Rec-1) cell lines. Among them, compound 5f exhibited the most potent antiproliferative effect on HL-60 cells. Further pharmacological research confirmed that compound 5f caused mitochondrial dysfunction and arrested the cell cycle in the G0/G1 phase to induce apoptosis of HL-60 cells. In addition, compound 5f also induced autophagy to inhibit the proliferation of HL-60 cells. Antibacterial screening revealed that compounds 2a-g and 5a-d showed modest activity against Gram-negative bacteria (Escherichia coli and Salmonella enterica subsp. enterica) with especially compounds 2c and 2d being potent inhibitors of Salmonella enterica subsp. enterica growth. Because of their promising anticancer and antibacterial activity, this series of compounds deserve further study.