Antitumor Profile of Carbon-Bridged Steroids (CBS) and Triterpenoids

Abstract

This review focuses on the rare group of carbon-bridged steroids (CBS) and triterpenoids found in various natural sources such as green, yellow-green, and red algae, marine sponges, soft corals, ascidians, starfish, and other marine invertebrates. In addition, this group of rare lipids is found in amoebas, fungi, fungal endophytes, and plants. For convenience, the presented CBS and triterpenoids are divided into four groups, which include: (a) CBS and triterpenoids containing a cyclopropane group; (b) CBS and triterpenoids with cyclopropane ring in the side chain; (c) CBS and triterpenoids containing a cyclobutane group; (d) CBS and triterpenoids containing cyclopentane, cyclohexane or cycloheptane moieties. For the comparative characterization of the antitumor profile, we have added several semi- and synthetic CBS and triterpenoids, with various additional rings, to identify possible promising sources for pharmacologists and the pharmaceutical industry. About 300 CBS and triterpenoids are presented in this review, which demonstrate a wide range of biological activities, but the most pronounced antitumor profile. The review summarizes biological activities both determined experimentally and estimated using the well-known PASS software. According to the data obtained, two-thirds of CBS and triterpenoids show moderate activity levels with a confidence level of 70 to 90%; however, one third of these lipids demonstrate strong antitumor activity with a confidence level exceeding 90%. Several CBS and triterpenoids, from different lipid groups, demonstrate selective action on different types of tumor cells such as renal cancer, sarcoma, pancreatic cancer, prostate cancer, lymphocytic leukemia, myeloid leukemia, liver cancer, and genitourinary cancer with varying degrees of confidence. In addition, the review presents graphical images of the antitumor profile of both individual CBS and triterpenoids groups and individual compounds.

In Silico Prediction of Steroids and Triterpenoids as Potential Regulators of Lipid Metabolism

“…The steroid 24,26-cyclo-19-norcholesta-1,3,5 (10),22-tetraen-3-ol (13) is characterized by the presence of an aromatic A ring containing a cyclopropane ring in the side chain was isolated from the Hainan soft coral Dendronephthya studeri [45]. The ring A-aromatic bile acid 3-hydroxy-19-norchola-1,3,5 (10),22-tetraen-24-oic acid (14) was isolated from methanol extract of the marine sponge Sollasella moretonensis, collected from the seabed of northern Queensland, Australia [46].…”

“…In both natural and synthetic steroids, when an additional ring is formed within the steroid skeleton, through a direct bond between any two carbon atoms (or more) of the steroid ring system or an attached side chain, such steroids (or triterpenoids) are called carbon-bridged steroids [13,[200][201][202].…”

“…Of the more than 500 carbon-bridged steroids and triterpenoids studied, we found only twelve lipids that have a confidence level of more than 90 percent as potential lipid regulators. We give their description and their sources in nature below [13,203].…”

“…Carbon-bridged steroids (CBS) and triterpenoids belong to a rare group of natural hormones found in various natural sources such as green, yellow-green, and red algae, sea sponges, soft corals, ascidians, starfish, and other marine invertebrates. In addition, this group of rare lipids is found in amoebas, fungi, fungal endophytes, and plants [13,203].…”

“…The regulation of lipid metabolism is of interest primarily in the context of the regulation of energy flow and the way of its integration with other energy sources in tissues. A special role in the regulation of lipid metabolism is played by hormones such as adrenaline and norepinephrine, glucagon, glucocorticoids, hormones of the anterior pituitary gland, as well as thyroxine and sex hormones [12][13][14][15][16][17][18][19][20].…”