Lipase inhibitory and LDL anti-oxidative triterpenes from Abies sibirica

In Silico Study, Physicochemical, and In Vitro Lipase Inhibitory Activity of α,β-Amyrenone Inclusion Complexes with Cyclodextrins

α,β-amyrenone (ABAME) is a triterpene derivative with many biological activities; however, its potential pharmacological use is hindered by its low solubility in water. In this context, the present work aimed to develop inclusion complexes (ICs) of ABAME with γ- and β-cyclodextrins (CD), which were systematically characterized through molecular modeling studies as well as FTIR, XRD, DSC, TGA, and SEM analyses. In vitro analyses of lipase activity were performed to evaluate possible anti-obesity properties. Molecular modeling studies indicated that the CD:ABAME ICs prepared at a 2:1 molar ratio would be more stable to the complexation process than those prepared at a 1:1 molar ratio. The physicochemical characterization showed strong evidence that corroborates with the in silico results, and the formation of ICs with CD was capable of inducing changes in ABAME physicochemical properties. ICs was shown to be a stronger inhibitor of lipase activity than Orlistat and to potentiate the inhibitory effects of ABAME on porcine pancreatic enzymes. In conclusion, a new pharmaceutical preparation with potentially improved physicochemical characteristics and inhibitory activity toward lipases was developed in this study, which could prove to be a promising ingredient for future formulations.

Biological activity evaluations of chemical constituents derived from Mongolian medicinal forage plants and their applications in combating infectious diseases and addressing health problems in humans and livestock

Mongolian nomadic people possess traditional knowledge of wild plants that grow in their areas of habitation. Many of these are forage plants in nature and are consumed by livestock. However, these plants are known to have medicinal and/or toxic properties. To establish a scientific understanding of the plants, and in turn, offer sound knowledge on their applications and effective use, it is essential to collect data pertaining to the chemical constituents of each plant. Therefore, the first objective of this study was to identify and determine the structural constituents of the forage plants that were available to our research group. Furthermore, in an attempt to demonstrate the biological activities of the isolated chemical compounds, we focused on solving some of the social issues affecting Mongolian communities, including protozoan diseases affecting livestock, vectors of infectious diseases, and the general health of humans and their livestock. The results of the chemical constituents derived from Mongolian medicinal plants and their biological activities that were studied in the recent decade are also described herein.

Temperate Zone Plant Natural Products-A Novel Resource for Activity against Tropical Parasitic Diseases

The use of plant-derived natural products for the treatment of tropical parasitic diseases often has ethnopharmacological origins. As such, plants grown in temperate regions remain largely untested for novel anti-parasitic activities. We describe here a screen of the PhytoQuest Phytopure library, a novel source comprising over 600 purified compounds from temperate zone plants, against in vitro culture systems for Plasmodium falciparum, Leishmania mexicana, Trypanosoma evansi and T. brucei. Initial screen revealed 6, 65, 15 and 18 compounds, respectively, that decreased each parasite's growth by at least 50% at 1-2 µM concentration. These initial hits were validated in concentration-response assays against the parasite and the human HepG2 cell line, identifying hits with EC50 < 1 μM and a selectivity index of >10. Two sesquiterpene glycosides were identified against P. falciparum, four sterols against L. mexicana, and five compounds of various scaffolds against T. brucei and T. evansi. An L. mexicana resistant line was generated for the sterol 700022, which was found to have cross-resistance to the anti-leishmanial drug miltefosine as well as to the other leishmanicidal sterols. This study highlights the potential of a temperate plant secondary metabolites as a novel source of natural products against tropical parasitic diseases.

Phytochemical and biological studies on rare and endangered plants endemic to China. Part XIV. Structurally diverse terpenoids from the twigs and needles of the endangered plant Picea brachytyla

A phytochemical investigation on the MeOH extract of the twigs and needles of the endangered plant Picea brachytyla led to the isolation and characterization of thirty-eight structurally diverse terpenoids. Seven of these molecules are previously undescribed, including three abietane-type (brachytylins A-C) and one labdane-type (brachytylin D) diterpenoids, an unseparated C-24 epimeric mixture of cycloartane-type triterpenoids (brachytylins E/F, ratio: 1:1), and a rare rearranged 12(1 → 6)-abeo-megastigmane glycoside (brachytylins G). Their structures and absolute configurations were determined by extensive spectroscopic (e.g., detailed 2D NMR and ECD) methods and/or X-ray diffraction analyses. All the isolates were evaluated for their inhibitory activities against the adenosine triphosphate (ATP)-citrate lyase (ACL) and the Src homology-2 domain containing protein tyrosine phosphatase-2 (SHP2). Among them, abiesadine J showed inhibitory effect against ACL, displaying an IC₅₀ value of 17 μM. 3S,23R-Dihydroxycycloart-24-en-26-oic acid exhibited inhibitory effect on SHP2, with an IC₅₀ value of 19 μM. Meanwhile, 3R*,23S*-dihydroxycycloart-24-en-26-oic acid was found to have inhibitory effects against both ACL and SHP2, with IC₅₀ values of 16 and 12 μM, respectively.

An Abies procera-derived tetracyclic triterpene containing a steroid-like nucleus core and a lactone side chain attenuates in vitro survival of both Fasciola hepatica and Schistosoma mansoni

Two economically and biomedically important platyhelminth species, Fasciola hepatica (liver fluke) and Schistosoma mansoni (blood fluke), are responsible for the neglected tropical diseases (NTDs) fasciolosis and schistosomiasis. Due to the absence of prophylactic vaccines, these NTDs are principally managed by the single class chemotherapies triclabendazole (F. hepatica) and praziquantel (S. mansoni). Unfortunately, liver fluke resistance to triclabendazole has been widely reported and blood fluke insensitivity/resistance to praziquantel has been observed in both laboratory settings as well as in endemic communities. Therefore, the identification of new anthelmintics is necessary for the sustainable control of these NTDs in both animal and human populations. Here, continuing our work with phytochemicals, we isolated ten triterpenoids from the mature bark of Abies species and assessed their anthelmintic activities against F. hepatica and S. mansoni larval and adult lifecycle stages. Full ¹H and ¹³C NMR-mediated structural elucidation of the two most active triterpenoids revealed that a tetracyclic steroid-like nucleus core and a lactone side chain are associated with the observed anthelmintic effects. When compared to representative mammalian cell lines (MDBK and HepG2), the most potent triterpenoid (700015; anthelmintic EC₅₀s range from 0.7 μM–15.6 μM) displayed anthelmintic selectivity (selectivity indices for F. hepatica: 13 for newly excysted juveniles, 46 for immature flukes, 2 for mature flukes; selectivity indices for S. mansoni: 14 for schistosomula, 9 for immature flukes, 4 for adult males and 3 for adult females) and induced severe disruption of surface membranes in both liver and blood flukes. S. mansoni egg production, a process responsible for pathology in schistosomiasis, was also severely inhibited by 700015. Together, our results describe the structural elucidation of a novel broad acting anthelmintic triterpenoid and support further investigations developing this compound into more potent analogues for the control of both fasciolosis and schistosomiasis.

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Abies species contain anthelmintic phytochemical triterpenoids.

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The triterpenoid 700015 affects larval, juvenile and adult fluke viabilities.

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700015 is moderately selective against both fluke species.

Triterpenoids

Covering: 2013. Previous review: Nat. Prod. Rep., 2015, 29, 1028-1065This review covers the isolation and structure determination of triterpenoids reported during 2013 including squalene derivatives, lanostanes, holostanes, cycloartanes, cucurbitanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes, isomalabaricanes and saponins; 350 references are cited.

General Toxicity and Antifungal Activity of a New Dental Gel with Essential Oil from Abies Sibirica L

Background

The aim of this study was to analyze the antifungal activity and the general toxicity of a new dental gel containing essential oil from the tree Abies sibirica L., which grows in the Republic of Kazakhstan.

Material/Methods

The essential oil from Abies sibirica L. was obtained by microwave heating method using the STARTE Microwave Extraction System. Adjutants used to prepare the oil were carbomer 974P, glycerin, polysorbate 80, xylitol, triethanolamine, and purified water, all allowed for medical usage. The antifungal activity of the essential oil was assessed by monitoring the optical density of Candida albicans in a microplate reader. The safety was determined by analyzing the acute and subacute toxicity.

Results

The essential oil obtained by the microwave heating method revealed a higher antifungal activity in comparison with the essential oil obtained by the steam distillation method. No obvious changes were detected in guinea pigs following cutaneous application of the gel. Enteral administration of the essential oil caused minimal functional and histological changes in mice after 4 weeks. The new harmless dental gel containing pine oil from Abies sibirica L. was provided for the purposes of this particular clinical research.

Conclusions

The high antifungal activity of the gel is the basis for more in-depth studies on its safety and pharmacological activity.

Triterpenoids from the branch and leaf of Abies fargesii

Eighteen triterpenoids, abifarines A-R, including fourteen previously unknown and four artifacts, together with six known ones, were isolated from the branch and leaf of Abies fargesii. Their structures were elucidated by spectroscopic data analysis. The relative configurations of abifarines A and F were further confirmed by single-crystal X-ray diffraction analysis with Mo Kα irradiation. All compounds were evaluated for their in vitro cytotoxicity against the mouse cancer B16 cell line, and human cancer HepG2 and MCF7 cell lines. (24R)-cycloartane-3β,24,25-triol and (24R)-cycloartane-3β,24,25,28-tetrol showed moderate anti-proliferative effect for B16 and HepG2 cell lines with IC50 values of 32.9, 19.5 μM and 26.4, 21.5 μM, respectively.

Triterpenoids from Abies faxoniana and their cytotoxic activities

Two previously unreported triterpenoids (1 and 2) and four known compounds were isolated from Abies faxoniana. Compound 1 has a α,β-unsaturated-γ-lactone ring conjugated with the C-22/23 olefin in the C-17 side chain. The structures of the new compounds were established on the basis of spectroscopic data analysis. These compounds were tested for their cytotoxicities against six human tumour cell lines. Compound 1 showed cytotoxic activities against MCF-7 and A549 cells with IC₅₀ values of 7.5 and 8.7 μM, respectively.

Epimeric spirolactone-type triterpenoids from Abies faxoniana Rehd

Phytochemical investigation of Abies faxoniana Rehd. led to the isolation of two pairs of new epimeric spirolactone-type triterpenoids (1/1' and 2/2') and 11 known terpenoids (3-13). Compounds 1/1' and 2/2' were isolated as epimeric mixtures due to the C-23 ketal tautomerism in their spirolactone structures. The dynamic HPLC manifested that the C-23 epimeric mixtures interconverted into each other in solution. Structure determinations were based on extensive NMR and HRESIMS spectroscopic analysis. Meanwhile, their cytotoxic activities were tested by MTT method. Compound 5 showed cytotoxicities against MCF-7 and A549 cells with IC50 values of 6.5 and 5.7μM, respectively. Compounds 1/1' had IC50 values of 10.0 and 12.3μM for Huh7 and SMMC7721 cells, respectively.

Terpenoids with anti-inflammatory activity from Abies chensiensis

The phytochemical investigation of Abies chensiensis led to the isolation and identification of nine new compounds including eight triterpenoids (1-8) and a new abietane-type diterpene (9), along with three known compounds (10-12). The absolute configuration of 9 was assigned by X-ray diffraction analysis. Compounds 1-11 were evaluated for the anti-inflammatory activity. Among the tested compounds, 1, 2, 5 and 6 exhibited potent inhibitory activity with IC50 values of 15.97, 18.73, 20.18 and 10.97μM, respectively.

Lanostane-type triterpenoids from Abies faxoniana and their DNA topoisomerase inhibitory activities

Nine lanostane-type triterpenoids were isolated from branches and leaves of Abies faxoniana, along with 10 known compounds. Two were isolated as inseparable mixtures of epimers at C-23 of the γ-lactone ring that had a lactol structure. The structures of the nine compounds were established by spectroscopic analysis and circular dichroism (CD) data. The absolute configurations at the stereogenic centres of two of the known compounds were confirmed by X-ray crystallography. One compound showed cytotoxic activities against HCT-116, MCF-7, and A549 cells with IC50 values of 8.9, 7.6, and 4.2μM, respectively. The isolated compounds were tested for their effects on human DNA topoisomerases I and II. One was found to be a selective inhibitor of human topo II activity with an IC50 value of 53.5μM, which was comparable to that of the topo II inhibitor etoposide (IC50=49.6μM).

Spirochensilides A and B, Two New Rearranged Triterpenoids from Abies chensiensis

Two new triterpenoids, spirochensilides A (1) and B (2) were isolated from Abies chensiensis. Comprehensive spectroscopic analysis revealed that 1 and 2 are the first example of triterpenoids possessing a unique 8,10-cyclo-9,10-seco and methyl-rearranged carbon skeleton. The single crystal X-ray diffraction analyses and computational methods allowed the absolute configuration assignments of the two compounds. A plausible biogenetic pathway of spirochensilide A (1) is also proposed.