Lanostane triterpenoids from the stems of Schisandra glaucescens

The role of botanical triterpenoids and steroids in bile acid metabolism, transport, and signaling: Pharmacological and toxicological implications

Bile acids (BAs) are synthesized by the host liver from cholesterol and are delivered to the intestine, where they undergo further metabolism by gut microbes and circulate between the liver and intestines through various transporters. They serve to emulsify dietary lipids and act as signaling molecules, regulating the host's metabolism and immune homeostasis through specific receptors. Therefore, disruptions in BA metabolism, transport, and signaling are closely associated with cholestasis, metabolic disorders, autoimmune diseases, and others. Botanical triterpenoids and steroids share structural similarities with BAs, and they have been found to modulate BA metabolism, transport, and signaling, potentially exerting pharmacological or toxicological effects. Here, we have updated the research progress on BA, with a particular emphasis on new-found microbial BAs. Additionally, the latest advancements in targeting BA metabolism and signaling for disease treatment are highlighted. Subsequently, the roles of botanical triterpenoids in BA metabolism, transport, and signaling are examined, analyzing their potential pharmacological, toxicological, or drug interaction effects through these mechanisms. Finally, a research paradigm is proposed that utilizes the gut microbiota as a link to interpret the role of these important natural products in BA signaling.

Cytotoxic lanostane triterpenoids from the ethanol extract of Schisandra viridis

Three new lanostane triterpenoids, designated as 6-hydroxyl schiglausin A (1), 29-hydroxyl schiglausin D (2), and 6-hydroxyl schiglausin G (3), were isolated from the ethanol extract of the stems of Schisandra viridis. Structural elucidation of all the compounds were performed by spectral methods such as 1D and 2D (¹H-¹H COSY, HMQC, and HMBC) NMR spectroscopy, in addition to high resolution mass spectrometry. The isolated compounds were tested in vitro for cytotoxic activities. As a result, compound 1 exhibited cytotoxic activities for all six tested human lung cancer cell lines with IC₅₀ values less than 10 μM.

Natural Products Targeting Liver X Receptors or Farnesoid X Receptor

Nuclear receptors (NRs) are a superfamily of transcription factors induced by ligands and also function as integrators of hormonal and nutritional signals. Among NRs, the liver X receptors (LXRs) and farnesoid X receptor (FXR) have been of significance as targets for the treatment of metabolic syndrome-related diseases. In recent years, natural products targeting LXRs and FXR have received remarkable interests as a valuable source of novel ligands encompassing diverse chemical structures and bioactive properties. This review aims to survey natural products, originating from terrestrial plants and microorganisms, marine organisms, and marine-derived microorganisms, which could influence LXRs and FXR. In the recent two decades (2000-2020), 261 natural products were discovered from natural resources such as LXRs/FXR modulators, 109 agonists and 38 antagonists targeting LXRs, and 72 agonists and 55 antagonists targeting FXR. The docking evaluation of desired natural products targeted LXRs/FXR is finally discussed. This comprehensive overview will provide a reference for future study of novel LXRs and FXR agonists and antagonists to target human diseases, and attract an increasing number of professional scholars majoring in pharmacy and biology with more in-depth discussion.

Triterpenoids From Kadsura coccinea With Their Anti-inflammatory and Inhibited Proliferation of Rheumatoid Arthritis-Fibroblastoid Synovial Cells Activities

One new 3,4-seco-17,13-friedo-lanostane triterpenoid heilaohuacid A (1), one new 3,4-seco-17,14-friedo-lanostane triterpenoid heilaohuacid B (2), five new 3,4-seco-lanostane triterpenoids heilaohuacids C-D (3–4) and heilaohumethylesters A-C (7–9), one new 3,4-seco-cycloartane triterpenoid heilaohuacid E (5), and one new intact-lanostane triterpenoid heilaohuacid F (6), together with twenty-two known analogues (10–31), were isolated from heilaohu. Their structures were determined using HR-ESI-MS data, 1D and 2D NMR spectra, ¹³C NMR calculations, and electronic circular dichroism (ECD) calculations. Heilaohuacids A and B (1 and 2) contain a 3,4-seco ring A and unprecedented migration of Me-18 from C-13 to C-17 or C-14 to C-18. This type of lanostane triterpenoid derivatives was rarely reported so far. More importantly, all compounds against inflammatory cytokines IL-6 and TNF-α levels on LPS-induced RAW 264.7 macrophages were evaluated, and compounds 4 and 31 significantly inhibited the release level of IL-6 with IC₅₀ values of 8.15 and 9.86 μM, respectively. Meanwhile, compounds 17, 18, and 31 significantly inhibited proliferation of rheumatoid arthritis-fibroblastoid synovial (RA-FLS) cells in vitro with IC₅₀ values of 7.52, 8.85, and 7.97 μM, respectively.

Xuetonglactones A-F: Highly Oxidized Lanostane and Cycloartane Triterpenoids From Kadsura heteroclita Roxb. Craib

Xuetonglactones A–F (1–6), six unreported highly oxidized lanostane- and cycloartane-type triterpenoids along with 22 known scaffolds (7–28) were isolated from the stems of Kadsura heteroclita (Roxb.) Craib. Compared with previous congeners, xuetonglactone A (1), possesses an unprecedented 20,21-α-epoxide, and xuetonglactone D (4) features an unusual 19-α-hydroperoxyl moiety. The structures and the absolute configurations of the compounds were established by extensive one- and two-dimensional NMR, and electronic circular dichroism (ECD) spectroscopic analysis, with those of 1 and 5 confirmed by single-crystal X-ray diffraction technique. Compounds 1 and 2 exhibited inhibition of iNOS activity in LPS-induced macrophages with IC₅₀ values of 22.0, and 17.0 μg/mL, respectively. While compounds 6, 7, 8, and 24 showed potent cytotoxic activities against human cervical cancer cell lines (HeLa) with the IC₅₀ values of 4.0, 5.8, 5.0, and 6.4 μM, and against human gastric cancer cells (BGC 823) with the IC₅₀ values of 2.0, 5.0, 2.5, and 2.0 μM, respectively. Moreover, plausible biogenetic pathways of (1–6) were also proposed.

Plant triterpenoids with bond-missing skeletons: biogenesis, distribution and bioactivity

Covering: up to December 2018 The polycyclic ABCD(E) framework of triterpenoids can miss a single endocyclic C-C bond as a result of a modification of the cyclization cascade that triggers their formation (interrupted- or diverted cascades), or can be the result of post-cyclization ring cleavage by late-stage oxidative modifications (seco-triterpenoids). Because of mechanistic and biogenetic differences, ring opening associated with loss of a skeletal fragment, as in nor-seco-triterpenoids (limonoids, quassinoids), will not be covered, nor will compounds where ring opening is part of a fragmentation cascade or of a multiple diversion from it. Even with these limitations, 342 bond-missing triterpenoids could be retrieved from the literature, with transversal distribution in the plant kingdom. Their structural diversity translates into a variety of biological targets, with dominance of potential applications in the realm of cancer, neuroprotection, and anti-infective therapy. In addition to the bioactivity and chemotaxonomic relevance of bond-missing triterpenoids, current knowledge on the genetic basis of interrupted- and diverted oxidosqualene cyclases will be summarized. This untapped source of enzymes could be useful to selectively modify triterpenoids by metabolic engineering, circumventing the bottlenecks of their isolation (poor yield or inadequate supply chain) to explore new areas of their chemical space.

Cytotoxic lanostane triterpenoids from the stems of Schisandra glaucescens

Phytochemical investigation on the stems of Schisandra glaucescens resulted into the isolation of three new lanostane triterpenoids, 12-hydroxyschiglausin B (1), 12-hydroxykadsuphilactone B (2), and 20R-hydroxyschinalactone C (3). Structural elucidation of all the compounds was accomplished by spectral methods. The isolated compounds were tested in vitro for cytotoxic activities. As a result, triterpenoids 1 and 2 showed cytotoxic activities for all six tested tumor cell lines with IC₅₀ values less than 15 μM.

Natural products as modulators of the nuclear receptors and metabolic sensors LXR, FXR and RXR

Nuclear receptors (NRs) represent attractive targets for the treatment of metabolic syndrome-related diseases. In addition, natural products are an interesting pool of potential ligands since they have been refined under evolutionary pressure to interact with proteins or other biological targets. This review aims to briefly summarize current basic knowledge regarding the liver X (LXR) and farnesoid X receptors (FXR) that form permissive heterodimers with retinoid X receptors (RXR). Natural product-based ligands for these receptors are summarized and the potential of LXR, FXR and RXR as targets in precision medicine is discussed.

Triterpenoids and lignans from the stems of Schisandra glaucescens

Two new triterpenoids, 24( E)-3 α,12 α-dihydroxyl-lanost-9(11),24-dien-26-oid acid (1) and 3,4- seco-24( Z)-6 α,7 β-dihydroxyl-cycloart-4(28),24-dien-3,26-dioic-3-methyl ester (2), and ten known ones (3-12), together with eight lignans (13-20), were isolated from the stems of Schisandra glaucescens. Their structures were established on the basis of extensive spectroscopic analyses. Compounds 1-3, 5-7, 9, 11-13 and 15-18 were isolated from this species for the first time. 1 and 2 were evaluated for their in vitro cytotoxicities against the mouse cancer B16 cell line, human cancer HepG2 and MCF7 cell lines by MTT assay.

FXR antagonism of NSAIDs contributes to drug-induced liver injury identified by systems pharmacology approach

Non-steroidal anti-inflammatory drugs (NSAIDs) are worldwide used drugs for analgesic, antipyretic, and anti-inflammatory therapeutics. However, NSAIDs often cause several serious liver injuries, such as drug-induced liver injury (DILI), and the molecular mechanisms of DILI have not been clearly elucidated. In this study, we developed a systems pharmacology approach to explore the mechanism-of-action of NSAIDs. We found that the Farnesoid X Receptor (FXR) antagonism of NSAIDs is a potential molecular mechanism of DILI through systematic network analysis and in vitro assays. Specially, the quantitative real-time PCR assay reveals that indomethacin and ibuprofen regulate FXR downstream target gene expression in HepG2 cells. Furthermore, the western blot shows that FXR antagonism by indomethacin induces the phosphorylation of STAT3 (signal transducer and activator of transcription 3), promotes the activation of caspase9, and finally causes DILI. In summary, our systems pharmacology approach provided novel insights into molecular mechanisms of DILI for NSAIDs, which may propel the ways toward the design of novel anti-inflammatory pharmacotherapeutics.

Triterpenoids

This review covers the isolation and structure determination of triterpenoids reported during 2012 including squalene derivatives, lanostanes, holostanes, cycloartanes, cucurbitanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes, isomalabaricanes and saponins; 348 references are cited.

Triterpenoids from the Schisandraceae family: an update

Plants from the Schisandraceae family produce architecturally interesting triterpenoids, including lanostanes, cycloartanes, and schinortriterpenoids. This review focuses on their structures, classifications, biogenetic pathways, syntheses, and bioactivities (from February 2008 to May 2014).

Lignans from the fruit of Schisandra glaucescens with antioxidant and neuroprotective properties

Two rare 7,8-seco-lignans (1, 2), three new lignan glycosides (3, 4a, 4b), and 10 known lignans (5-14) were isolated from the fruit of Schisandra glaucescens Diels. The absolute configurations of 1 and 2 were determined by comparing their experimental and calculated electronic circular dichroism spectra. The molecular structures of the new compounds (3, 4a, and 4b), including their absolute configurations, were determined using various spectroscopic methods and hydrolysis reactions. The antioxidant activities of the isolated compounds were tested using 2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power assays. Compounds 4, 7, 8, 10, 11, and 12 exhibited antioxidant activities of varying potential in both assays. Of these compounds, 7 showed the strongest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity, with IC50 values of 15.7 (150 μM DPPH) and 34.6 μM (300 μM DPPH), respectively, and 4, 12, and 7 displayed higher total antioxidant activities than Trolox in the ferric reducing antioxidant power assay. The neuroprotective effects of these compounds against Aβ25-35-induced cell death in SH-SY5Y cells were also investigated. Compounds 1, 2, 6, 7, 8, 11, and 12 exhibited statistically significant neuroprotective effects against Aβ25-35-induced SH-SY5Y cell death compared with the group treated only with Aβ25-35.

Two new compounds from Schisandra glaucescens

One new lignan (7S,8R,7'R,8'R)-7-(3,4-methylenedioxyphenyl)-8,8'-dimethyl-8'-hydroxyl-7'-methoxyl-7'-(3',4'-methylenedioxyphenyl)-tetrahydrofuran (1), one new sesquiterpene 2-hydroxy-11,12-dehydrocalamenene (2), one new natural product erythro-1-(3,4-dimethoxyphenyl)-4-(3,4-methylenedioxyphenyl)-2,3-dimethyl-butane (3), and two known lignans (+)-anwulignan(erythro-1-(4-hydroxy-3-methoxyphenyl)-4-(3,4-methylenedioxyphenyl)-2,3-dimethyl-butane) (4) and ( - )-zuonin-A (5) were isolated from the stems of Schisandra glaucescens Diels. Their structures were elucidated by spectroscopic methods. The cytotoxicity of compounds 1 and 2 was assayed.