Semisynthetic modifications of antitubercular lanostane triterpenoids from Ganoderma

Synthesis and Investigation of Biological Activity of New Betulonic Acid Derivatives Containing 1,2,3-Triazole Fragments

The results of this study showed that the compounds synthesized by the authors have significant potential due to their antibacterial and cytotoxic properties. The apparent antibacterial activity demonstrated by the compounds suggests that they are active antimicrobial agents against common microbial pathogens that cause various socially significant infectious diseases. Compound 6 showed pronounced antimicrobial activity against the Gram-positive test strain Staphylococcus aureus ATCC 6538, and compound 7 demonstrated pronounced antimicrobial activity against the Gram-negative test strain Escherichia coli ATCC 25922 (MIC = 6.3 µg/mL). This allowed us to consider these compounds to have great potential.

Promising Ursolic Acid as a Novel Antituberculosis Agent: Current Progress and Challenges

Tuberculosis (TB) stands as the second most prevalent cause of global human mortality from infectious diseases. In 2022, the World Health Organization documented an estimated number of global TB cases reaching 7.5 million, which causes death for 1.13 million patients. The continuous growth of drug-resistant TB cases due to various mutations in the Mycobacterium tuberculosis (MTB) strain, raises the urgency of the exploration of novel anti-TB treatments. Ursolic acid (UA) is a natural pentacyclic triterpene found in various plants that has shown potential as a novel anti-TB agent. This review aims to provide an overview of the therapeutic prospects of UA against MTB, with a particular emphasis on in silico, in vitro, and in vivo studies. Various mechanisms of action of UA against MTB are briefly recapped from in silico studies, such as enoyl acyl carrier protein reductase inhibitors, FadA5 (Acetyl-CoA acetyltransferase) inhibitors, tuberculosinyl adenosine transferase inhibitors, and small heat shock protein 16.3 inhibitor. The potential of UA to overcome drug resistance and its synergistic effects with existing antituberculosis drugs are briefly explained from in vitro studies using a variety of methods, such as Microplate Alamar Blue Assay, Mycobacteria Growth Indicator Tube 960 and Resazurin Assays, morphological change evaluation using transmission electron microscopy, and in vivo studies using BALB/C infected with multi drug resistant clinical isolates. Besides its promising mechanism as an antituberculosis drug, its complex chemical composition, limited availability and supply, and lack of intellectual property are also reviewed as those are the most frequently occurring challenges that need to be addressed for the successful development of UA as novel anti-TB agent.

Natural Bio-Compounds from Ganoderma lucidum and Their Beneficial Biological Actions for Anticancer Application: A Review

Ganoderma lucidum (G. lucidum) has been known for many centuries in Asian countries under different names, varying depending on the country. The objective of this review is to investigate the scientific research on the natural active bio-compounds in extracts obtained from G. lucidum with significant biological actions in the treatment of cancer. This review presents the classes of bio-compounds existing in G. lucidum that have been reported over time in the main databases and have shown important biological actions in the treatment of cancer. The results highlight the fact that G. lucidum possesses important bioactive compounds such as polysaccharides, triterpenoids, sterols, proteins, nucleotides, fatty acids, vitamins, and minerals, which have been demonstrated to exhibit multiple anticancer effects, namely immunomodulatory, anti-proliferative, cytotoxic, and antioxidant action. The potential health benefits of G. lucidum are systematized based on biological actions. The findings present evidence regarding the lack of certainty about the effects of G. lucidum bio-compounds in treating different forms of cancer, which may be due to the use of different types of Ganoderma formulations, differences in the study populations, or due to drug-disease interactions. In the future, larger clinical trials are needed to clarify the potential benefits of pharmaceutical preparations of G. lucidum, standardized by the known active components in the prevention and treatment of cancer.

Chemical analysis and antitubercular activity evaluation of the dried mycelial powders of the basidiomycete Ganoderma australe TBRC-BCC 22314

The isolation of lanostane triterpenoids possessing significant anti-tuberculosis (anti-TB) activity from mycelial cultures of the basidiomycete Ganoderma australe strain TBRC-BCC 22314 was previously reported. To demonstrate the potential of the dried mycelial powder for utilization in anti-TB medicinal products, its authentic chemical analysis was performed. Considering the possibility of the changes in the lanostane compositions and anti-TB activity by sterilization, both autoclave treated and non-autoclaved mycelial powder materials were chemically investigated. The study led to the identification of the lanostanes responsible for the activity of the mycelial extract against Mycobacterium tuberculosis H37Ra. The anti-TB activity of the extracts from autoclaved and non-autoclaved mycelial powders were the same (MIC 3.13 μg/mL). However, the analytical results revealed several unique chemical conversions of the lanostanes under the sterilization conditions. The most potent major lanostane, ganodermic acid S (1), was shown to be significantly active also against the extensively drug-resistant (XDR) strains of M. tuberculosis.

Progress Toward the Asymmetric de Novo Synthesis of Lanostanes: A Counter Biomimetic Cucurbitane-to-Lanostane Type Transformation

An oxidative rearrangement has been established that enables a cucurbitane-to-lanostane type rearrangement that is counter to known biomimetic transformations that proceed in an opposite direction by way of a lanostane-to-cucurbitane transformation. Here, an oxidative dearomatization/Wagner-Meerwein rearrangement with a substrate bearing the characteristic cucurbitane triad of quaternary centers at C9, C13 and C14, and possessing an alkene at C11-C12, proceeds in a manner that selectively shifts the methyl group at C9 to C10 in concert with the establishment of a sterically hindered allylic cation. The major product isolated from this transformation is formed by trapping of the allylic cation by addition of acetate to C12, rather than termination of the cascade by loss of a proton at C8. While proceeding by way of a unique sequence of bond-forming reactions that begins by oxidative dearomatization, this process achieves what we believe is an unprecedented cucurbitane-to-lanostane transformation, generating a product that contains the characteristic lantostane triad of quaternary centers at C10, C13 and C14 while also delivering a functionalized C-ring.

A nostoxanthin-producing bacterium, Sphingomonas nostoxanthinifaciens sp. nov., alleviates the salt stress of Arabidopsis seedlings by scavenging of reactive oxygen species

A novel, nostoxanthin-producing, endophytic bacterium, designated as AK-PDB1-5^T, was isolated from the needle-like leaves of the Korean fir (Abies koreana Wilson) collected from Mt. Halla in Jeju, South Korea. A 16S rRNA sequence comparison indicated that the closest phylogenetic neighbors were Sphingomonas crusticola MIMD3^T (95.6%) and Sphingomonas jatrophae S5-249^T (95.3%) of the family Sphingomonadaceae. Strain AK-PDB1-5^T had a genome size of 4,298,284 bp with a 67.8% G + C content, and digital DNA-DNA hybridization and OrthoANI values with the most closely related species of only 19.5-21% and 75.1-76.8%, respectively. Cells of the strain AK-PDB1-5^T were Gram-negative, short rods, oxidase- and catalase-positive. Growth occurred at pH 5.0-9.0 (optimum pH 8.0) in the absence of NaCl at 4-37°C (optimum 25-30°C). Strain AK-PDB1-5^T contained C_14:0 2OH_, C_16:0 and summed feature 8 as the major cellular fatty acids (> 10%), while sphingoglycolipid, phosphatidylethanolamine, phosphatidylglycerol, phospholipids and lipids were found to be the major polar lipids. The strain produces a yellow carotenoid pigment; natural products prediction via AntiSMASH tool found zeaxanthin biosynthesis clusters in the entire genome. Biophysical characterization by ultraviolet-visible absorption spectroscopy and ESI-MS studies confirmed the yellow pigment was nostoxanthin. In addition, strain AK-PDB1-5^T was found significantly promote Arabidopsis seedling growth under salt conditions by reducing reactive oxygen species (ROS). Based on the polyphasic taxonomic analysis results, strain AK-PDB1-5^T was determined to be a novel species in the genus Sphingomonas with the proposed name Sphingomonas nostoxanthinifaciens sp. nov. The type strain is AK-PDB1-5^T (= KCTC 82822^T = CCTCC AB 2021150^T).

Toward the Asymmetric de Novo Synthesis of Lanostanes: Construction of 7,11-Dideoxy-Δ5-lucidadone H

Efforts to establish an asymmetric entry to hexanorlanostanes has resulted in a concise synthesis of 7,11-dideoxy-Δ5-lucidadone H from epichlorohydrin. By exploiting metallacycle-mediated annulative cross-coupling (to establish a functionalized hydrindane) and stereoselective formation of the steroidal C9-C10 bond to establish a stereodefined 9-alkyl estrane, 14 subsequent steps have been established to generate a hexanorlanostane system. Key transformations include formal inversion of the C13 quaternary center, oxidative dearomatization/group-selective Wagner-Meerwein rearrangement, and Lewis acid mediated semi-Pinacol rearrangement.

Fungal-derived compounds and mycogenic nanoparticles with antimycobacterial activity: a review

Tuberculosis (TB) is a persistent lung infection caused by Mycobacterium tuberculosis. The disease is characterized by high mortality rates of over 1 million per year. Unfortunately, the potency and effectiveness of currently used anti-TB drugs is gradually decreasing due to the constant development of persistence and resistance by M. tuberculosis. The adverse side effects associated with current anti-TB drugs, along with anti-TB drug resistance, present an opportunity to bio-prospect novel potent anti-TB drugs from unique sources. Fundamentally, fungi are a rich source of bioactive secondary metabolites with valuable therapeutic potential. Enhancing the potency and effectiveness of fungal-based anti-TB drug leads by chemical synthesis and/or modification with nanomaterials, may result in the discovery of novel anti-TB drugs. In this review, the antimycobacterial activity of fungal-derived compounds and mycogenic nanoparticles are summarized. Numerous fungal-derived compounds as well as some mycogenic nanoparticles that exhibit strong antimycobacterial activity that is comparable to that of approved drugs, were found. If fully explored, fungi holds the promise to become key drivers in the generation of lead compounds in TB-drug discovery initiatives.