Metabolites from Aerial Parts of Glycyrrhiza foetida as Modulators of Targets Related to Metabolic Syndrome.

A detailed phytochemical investigation has been carried out on the aerial parts of G. foetida leading to the isolation of 29 pure compounds, mainly belonging to the amorfrutin and polyphenol classes. Among them, the new amorfrutin N (5) and exiguaflavone L (21) were isolated and their structures elucidated by means of HR-ESIMS and NMR. All the isolated compounds were investigated for modulation of mitochondrial activity and stimulation of glucose uptake via GLUT transporters, two metabolic processes involved in intracellular glucose homeostasis, which, therefore, correlate with the incidence of metabolic syndrome. These experiments revealed that amorfrutins were active on both targets, with amorfrutin M (17) and decarboxyamorfrutin A (2) emerging as mitochondrial stimulators, and amorfrutin 2 (12) as a glucose uptake promoter. However, members of the rich chalcone/flavonoid fraction also proved to contribute to this activity.

Glucose Uptake-Stimulating Metabolites from Aerial Parts of Centaurea sicula.

A comprehensive phytochemical investigation of aerial parts obtained from Centaurea sicula L. led to the isolation of 14 terpenoids (1-14) and nine polyphenols (15-23). The sesquiterpenoid group (1-11) included three structural families, namely, elemanolides (1-6), eudesmanolides (7 and 8), and germacranolides (9-11) with four unreported secondary metabolites (5-8), whose structure has been determined by extensive spectroscopic analysis, including 1D/2D NMR, HR-MS, and chemical conversion. Moreover, an unprecedented alkaloid, named siculamide (24), was structurally characterized, and a possible biogenetic origin was postulated. Inspired by the traditional use of the plant and in the frame of ongoing research on compounds with potential activity on metabolic syndrome, all the isolated compounds were evaluated for their stimulation of glucose uptake, disclosing remarkable activity for dihydrocnicin (10) and the lignan salicifoliol (15).

The Eleutherococcus senticosus fruits' intractum affects changes in the transepithelial electric potential in the distal section of the rabbit's large intestine and inhibits hyaluronidase.

ETHNOPHARMACOLOGICAL RELEVANCE: Eleutherococcus senticosus (Rupr. et Maxim.) Maxim. has been used in traditional Russian medicine due to its recognized immunostimulant and anti-inflammatory activities. Compounds present in the fruits have demonstrated the capability to modulate the activity of enzymes such as hyaluronidase, suggesting their potential value in the development of effective therapies for various conditions where anti-inflammatory properties are beneficial, such as gastrointestinal diseases and tumor growth. AIM OF THE STUDY: In order to support the use of the fruits in folk medicine, this study is aimed to evaluate, post-mortem, the impact of E. senticosus fruits intractum (40 % extract made from fresh fruits) on the transepithelial electrogenic transport of sodium ions in the colon. The objective of this study was also to examine the impact of the intractum on proinflammatory serum hyaluronidase in children diagnosed with acute leukemia. METHODS: The study employed the Ussing technique to examine electrophysiological characteristics of isolated epithelial tissue, using the distal colon wall isolated from 10 New Zealand white male rabbits. The effect of the intractum on the inhibition of human serum hyaluronidase was examined with turbidimetric screening methods, using the blood samples collected from patients diagnosed with acute leukemia. RESULTS: For the first time, we discovered that the intractum used in the stimulation fluid, caused hyperpolarization reactions in colon tissue. Statistical analysis showed that these reactions were significantly different in relation to the control. The intractum significantly inhibited hyaluronidase activity with the mean value by group of 60 %, and 40 % for aescin used as a control. CONCLUSION: The results support the traditional use of the fruits in inflammatory-related diseases. The use of intractum of E. senticosus on the distal colon wall demonstrates its protective effect on the wall integrity and in a relation to hyaluronidase inhibition may additionally indicate its anti-inflammatory property. Thus, the results mean that the intractum may be used in colon-related diseases.

Novel Skeletal Rearrangements of the Tigliane Diterpenoid Core.

To investigate the role of the secondary 5-hydroxy group in the activity of the anticancer drug tigilanol tiglate (2b) (Stelfonta), oxidation of this epoxytigliane diterpenoid from the Australian rainforest plant Fontainea picrosperma was attempted. Eventually, 5-dehydrotigilanol tiglate (3a) proved too unstable to be characterized in terms of biological activity and, therefore, was not a suitable tool compound for bioactivity studies. On the other hand, a series of remarkable skeletal rearrangements associated with the presence of a 5-keto group were discovered during its synthesis, including a dismutative ring expansion of ring A and a mechanistically unprecedented dyotropic substituent swap around the C-4/C-10 bond. Taken together, these observations highlight the propensity of the α-hydroxy-ß-diketone system to trigger complex skeletal rearrangements and pave the way to new areas of the natural products chemical space.

Hydroxylated cyclopamine analogues from Veratrum californicum and their hedgehog pathway inhibiting activity.

Cyclopamine (1), the teratogenic steroidal alkaloid isolated from corn lily (Veratrum californicum), has recently gained renewed interest due to its anticancer potential, that has been translated into the FDA approval of three Hedgehog (Hh) pathway inhibiting antitumor drugs. A chemical analysis of mother liquors obtained from crystallization of cyclopamine, extracted from roots and rhizomes of V. californicum, resulted in the isolation of two unprecedented cyclopamine analogues, 18-hydroxycyclopamine (2) and 24R-hydroxycyclopamine (3), the first compounds of this class to show modifications on rings D-F. The stereostructures of these new natural compounds have been established based on a detailed MS and 1D/2D NMR investigation. The isolated compounds were evaluated with the dual-luciferase bioassay for their inhibition of the hedgehog pathway in comparison to cyclopamine, providing new insights into the structure-activity relationships for this class of compounds.

Phytochemical profile and anti-inflammatory activity of a commercially available Rhodiola rosea root extract.

Rhodiola rosea roots and rhizomes hold an important place in the folk medicines of Russia, Scandinavia, Mongolia, and China as a health supplement for stimulating the nervous system, enhancing physical and mental performances, and nowadays they constitute the active ingredient in many popular commercial preparations sold worldwide as food additives, pharmaceutical remedies, and drinks. This study was aimed at providing a detailed phytochemical characterization of the Rhodiola 5%, a commercially available extract of R. rosea roots, and resulted in the characterization of 18 secondary metabolites, including 13 polyphenols and 6 terpenoids, and in the discovery of the new rhodiosidin (5), the first R. rosea metabolite to show both terpenoid and cinnamoyl moieties. The 5-lipoxygenase inhibiting activity of the main components was characterized and disclosed that rosiridin (6), kenposide A and rosavins are mainly responsible for this activity of the extract.

Cryptic Epoxytiglianes from the Kernels of the Blushwood Tree (Fontainea picrosperma).

The kernels of the Australian blushwood tree (Fontainea picrosperma) are the source of the veterinary anticancer drug tigilanol tiglate (2a, Stelfonta) and contain a concentration of phorboids significantly higher than croton oil, the only abundant source of these compounds previously known. The oily matrix of the blushwood kernels is composed of free fatty acids and not by glycerides as found in croton oil. By active partitioning, it was therefore possible to recover and characterize for the first time a cryptic tigliane fraction, that is, the diterpenoid fraction that, because of its lipophilicity, could not be obtained by solvent partition of crude extracts. The cryptic tigliane fraction accounted for ca. 30% of the tigliane kernel titer and was quantified by 1H NMR spectroscopy and profiled by HPLC-MS. Long-chain (linoleates and/or oleates) 20-acyl derivatives of the epoxytigliane diesters tigilanol tiglate (EBC-46, 2a), EBC-47 (4a), EBC-59 (5a), EBC-83 (6a), and EBC-177 (7a) were identified. By chemoselective acylation of EBC-46 (2a) and EBC-177 (7a) the natural triesters 2b and 7b and a selection of analogues were prepared to assist identification of the natural compounds. The presence of a free C-20 hydroxy group is a critical requirement for PKC activation by phorbol esters. The unexpected activity of 20-linoleoyl triester 2b in a cytotoxicity assay based on PKC activation was found to be related mainly to its hydrolysis to tigilanol tiglate (2a) under the prolonged conditions of the assay, while other esters were inactive. Significant differences between the esterification profile of the epoxytigliane di- and triesters exist in F. picrosperma, suggesting a precise, yet elusive, blueprint of acyl decoration for the tigliane polyol 5-hydroxyepoxyphorbol.

A Nrf-2 Stimulatory Hydroxylated Cannabidiol Derivative from Hemp (Cannabis sativa).

A phytochemical analysis of mother liquors obtained from crystallization of CBD from hemp (Cannabis sativa), guided by LC-MS/MS and molecular networking profiling and completed by isolation and NMR-based characterization of constituents, resulted in the identification of 13 phytocannabinoids. Among them, anhydrocannabimovone (5), isolated for the first time as a natural product, and three new hydroxylated CBD analogues (1,2-dihydroxycannabidiol, 6, 3,4-dehydro-1,2-dihydroxycannabidiol, 7, and hexocannabitriol, 8) were obtained. Hexocannabitriol (8) potently modulated, in a ROS-independent way, the Nrf2 pathway, outperforming all other cannabinoids obtained in this study and qualifying as a potential new chemopreventive chemotype against cancer and other degenerative diseases.

Euphocactoside, a New Megastigmane Glycoside from Euphorbia cactus Growing in Saudi Arabia.

A phytochemical investigation of the aerial parts of Euphorbia cactus Ehrenb. ex Boiss. revealed a new megastigmane, euphocactoside (5), along with eleven known metabolites. Euphocactoside (5) is the 3-O-glucoside derivative of a polyhydroxylated megastigmane showing unprecedented structural features. The structure of euphocactoside, including stereochemical details, was elucidated by extensive spectroscopic analysis based on 1D and 2D nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HR-ESIMS). The isolated compounds were evaluated for their cytotoxic activity against three different human cancer cell lines, namely, A549 (lung), LoVo (colon), and MCF-7 (breast), using MTT assay, and moderate to marginal activities were observed for compounds 1-3, 8 and 9 against all three cell lines.

Cytotoxic Compounds from Alcyoniidae: An Overview of the Last 30 Years.

The octocoral family Alcyoniidae represents a rich source of bioactive substances with intriguing and unique structural features. This review aims to provide an updated overview of the compounds isolated from Alcyoniidae and displaying potential cytotoxic activity. In order to allow a better comparison among the bioactive compounds, we focused on molecules evaluated in vitro by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, by far the most widely used method to analyze cell proliferation and viability. Specifically, we surveyed the last thirty years of research, finding 153 papers reporting on 344 compounds with proven cytotoxicity. The data were organized in tables to provide a ranking of the most active compounds, to be exploited for the selection of the most promising candidates for further screening and pre-clinical evaluation as anti-cancer agents. Specifically, we found that (22S,24S)-24-methyl-22,25-epoxyfurost-5-ene-3ß,20ß-diol (16), 3ß,11-dihydroxy-24-methylene-9,11-secocholestan-5-en-9-one (23), (24S)-ergostane-3ß,5α,6ß,25 tetraol (146), sinulerectadione (227), sinulerectol C (229), and cladieunicellin I (277) exhibited stronger cytotoxicity than their respective positive control and that their mechanism of action has not yet been further investigated.

Phytochemical profile of Centevita®, a Centella asiatica leaves extract, and isolation of a new oleanane-type saponin.

Centella asiatica is a popular medicinal plant and several phytotherapic products in the market include its extracts as active constituents. A LC-MS guided phytochemical investigation on the commercial C. asiatica leaves extract named Centevita® allowed characterization and quantification of 24 secondary metabolites including 10 polyphenols and 14 ursane- or oleanane-type triterpenoids in the sapogenin or saponin form. This metabolomic analysis, besides confirming that the triterpenoid fraction roughly accounts for 45% of the extract weight, also resulted in the discovery of isoterminoloside, a new triglycoside saponin of the unprecedented 2α,3ß,6ß,23-tetrahydroxyolean-13(18)-en-28-oic acid (isoterminolic acid). The structure of isoterminoloside was characterized by a detailed ESI-MS and NMR investigation.

Total Synthesis of the Natural Chalcone Lophirone E, Synthetic Studies toward Benzofuran and Indole-Based Analogues, and Investigation of Anti-Leishmanial Activity.

The potential of natural and synthetic chalcones as therapeutic leads against different pathological conditions has been investigated for several years, and this class of compounds emerged as a privileged chemotype due to its interesting anti-inflammatory, antimicrobial, antiviral, and anticancer properties. The objective of our study was to contribute to the investigation of this class of natural products as anti-leishmanial agents. We aimed at investigating the structure-activity relationships of the natural chalcone lophirone E, characterized by the presence of benzofuran B-ring, and analogues on anti-leishmania activity. Here we describe an effective synthetic strategy for the preparation of the natural chalcone lophirone E and its application to the synthesis of a small set of chalcones bearing different substitution patterns at both the A and heterocyclic B rings. The resulting compounds were investigated for their activity against Leishmania infantum promastigotes disclosing derivatives 1 and 28a,b as those endowed with the most interesting activities (IC50 = 15.3, 27.2, 15.9 µM, respectively). The synthetic approaches here described and the early SAR investigations highlighted the potential of this class of compounds as antiparasitic hits, making this study worthy of further investigation.

Asporychalasin, a bioactive cytochalasan with an unprecedented 6/6/11 skeleton from the Red Sea sediment Aspergillus oryzae.

The cytochalasan asporychalasin (1) was obtained from the marine fungus Aspergillus oryzae, isolated from the Red Sea sediments collected off Jeddah, Saudi Arabia. The chemical structure of 1 was elucidated by extensive spectroscopic analysis and quantum-mechanical calculations of 13C NMR resonances and ECD to possess an unprecedented 6/6/11-fused tricyclic skeleton, including an isoquinolindione ring in place of the typical isoindolone. Asporychalasin exhibited moderate antiproliferative activity against three human cancer cell lines, lung carcinoma (A549), liver carcinoma (HepG2), and breast carcinoma (MCF7), and no toxicity on zebrafish embryos.

Phytochemical Analysis of Anvillea garcinii Leaves: Identification of Garcinamines F-H and Their Antiproliferative Activities.

Anvillea garcinii is a medicinal plant used in the Arab region for intestinal diseases, lung and liver diseases, digestive problems, and as an antidiabetic agent. Repeated chromatographic purifications of A. garcinii leaves led to the isolation of three undescribed guaiane sesquiterpene derivatives, named garcinamines F-H, characterized by the presence of an amino acid unit, along with five known sesquiterpene lactones (garcinamines B-E and 9ß-hydroxyparthenolide). The structures of the new compounds were established using spectroscopic (1D and 2D NMR) and spectrometric methods (ESIMS). Garcinamine H possesses a double bond at the Δ1,10 position, a structural feature rarely reported in guaianolide-type sesquiterpenes. The antiproliferative activity of the isolated sesquiterpenes was screened against three different cancer cell lines, and 9ß-hydroxyparthenolide and garcinamines C and D displayed significant effects against lung carcinoma (A549), colon carcinoma (LoVo), and breast carcinoma (MCF7) cell lines.

Antiproliferative Illudalane Sesquiterpenes from the Marine Sediment Ascomycete Aspergillus oryzae.

The new asperorlactone (1), along with the known illudalane sesquiterpene echinolactone D (2), two known pyrones, 4-(hydroxymethyl)-5-hydroxy-2H-pyran-2-one (3) and its acetate 4, and 4-hydroxybenzaldehyde (5), were isolated from a culture of Aspergillus oryzae, collected from Red Sea marine sediments. The structure of asperorlactone (1) was elucidated by HR-ESIMS, 1D, and 2D NMR, and a comparison between experimental and DFT calculated electronic circular dichroism (ECD) spectra. This is the first report of illudalane sesquiterpenoids from Aspergillus fungi and, more in general, from ascomycetes. Asperorlactone (1) exhibited antiproliferative activity against human lung, liver, and breast carcinoma cell lines, with IC50 values < 100 µM. All the isolated compounds were also evaluated for their toxicity using the zebrafish embryo model.

Isomadecassoside, a New Ursane-Type Triterpene Glycoside from Centella asiatica Leaves, Reduces Nitrite Levels in LPS-Stimulated Macrophages.

A madecassoside-rich fraction obtained from the industrial purification of Centella asiatica leaves afforded a new triterpene glycoside, named isomadecassoside (4), characterized by an ursane-type skeleton and migration of the double bond at Δ20(21) in ring E. The structure of isomadecassoside was established by means of HR-ESIMS and detailed analysis of 1D and 2D NMR spectra, which allowed a complete NMR assignment. Studies on isolated J774A.1 macrophages stimulated by LPS revealed that isomadecassoside (4) inhibited nitrite production at non-cytotoxic concentrations, thus indicating an anti-inflammatory effect similar to that of madecassoside.

Inhibitory effects of cynaropicrin on human melanoma progression by targeting MAPK, NF-κB, and Nrf-2 signaling pathways in vitro.

Malignant melanoma is the deadliest skin cancer, due to its propensity to metastasize. MAPKs and NF-κB pathways are constitutively activated in melanoma and promote cell proliferation, cell invasion, metastasis formation, and resistance to therapeutic regimens. Thus, they represent potential targets for melanoma prevention and treatment. Phytochemicals are gaining considerable attention for the management of melanoma because of their several cellular and molecular targets. A screening of a small library of sesquiterpenes lactones selected cynaropicrin, isolated from the aerial parts of Centaurea drabifolia subsp. detonsa, for its potential anticancer effect against melanoma cells. Treatment of human melanoma cells A375 with cynaropicrin resulted in inhibition of cell proliferation and induction of caspase-3-dependent apoptosis. Furthermore, cynaropicrin reduced several cellular malignant features such migration, invasion, and colonies formation through the inhibition of ERK1/2 and NF-κB activity. Cynaropicrin was able to reduce intracellular reactive oxygen species generation, which are involved in all the stages of carcinogenesis. Indeed, cynaropicrin increased the expression of several antioxidant genes, such as glutamate-cysteine ligase and heme oxygenase-1, by promoting the activation of the transcription factor Nrf-2. In conclusion, our results individuate cynaropicrin as a potential adjuvant chemotherapeutic agent for melanoma by targeting several protumorigenic signaling pathways.

The allylic oxidation of tigliane esters.

As part of a study on the structure-activity relationships of the anticancer agent tigilanol tiglate (EBC-46, 2), the allylic oxidation of phorbol triacetate (1c) and of the acetonide of its 3αH-dihydroderivative (5) was investigated. The aim was to introduce an oxygen function at C-5 en route to point-like analogues of 2, but functionalization of C-10 was instead observed. This was followed by oxidative fragmentation of ring B to the 9,10-secotigliane derivative 6 and oxidation of the endocyclic Δ6 double bond to the C-6/C-10 oxygen bridged 7-oxotigliane 7. Despite the over-functionalization of ring B, these observations suggest the possibility to modify positions overlooked in the oxidase phase of tigliane biosynthesis and explore novel areas of the phorbol chemical space.

Identification and Characterization of Cannabimovone, a Cannabinoid from Cannabis sativa, as a Novel PPARγ Agonist via a Combined Computational and Functional Study.

Phytocannabinoids (pCBs) are a large family of meroterpenoids isolated from the plant Cannabis sativa. Δ9-Tetrahydrocannabinol (THC) and cannabidiol (CBD) are the best investigated phytocannabinoids due to their relative abundance and interesting bioactivity profiles. In addition to various targets, THC and CBD are also well-known agonists of peroxisome proliferator-activated receptor gamma (PPARγ), a nuclear receptor involved in energy homeostasis and lipid metabolism. In the search of new pCBs potentially acting as PPARγ agonists, we identified cannabimovone (CBM), a structurally unique abeo-menthane pCB, as a novel PPARγ modulator via a combined computational and experimental approach. The ability of CBM to act as dual PPARγ/α agonist was also evaluated. Computational studies suggested a different binding mode toward the two isoforms, with the compound able to recapitulate the pattern of H-bonds of a canonical agonist only in the case of PPARγ. Luciferase assays confirmed the computational results, showing a selective activation of PPARγ by CBM in the low micromolar range. CBM promoted the expression of PPARγ target genes regulating the adipocyte differentiation and prevented palmitate-induced insulin signaling impairment. Altogether, these results candidate CBM as a novel bioactive compound potentially useful for the treatment of insulin resistance-related disorders.

Effects of Azadirachta indica seed kernel extracts on early erythrocytic schizogony of Plasmodium berghei and pro-inflammatory response in inbred mice.

BACKGROUND: Medicinal plant research may contribute to develop new pharmacological control tools for vector borne diseases, such as malaria. METHODS: The effects of methanol extracts (ME) obtained from seed kernel of ripe and unripe Azadirachta indica fruits were studied on erythrocytic proliferation of the rodent malaria parasite Plasmodium berghei strain ANKA and on mice pro-inflammatory response, as evaluated by measuring the matrix-metalloproteinase-9 (MMP-9) and tumour necrosis factor (TNF) plasma levels, in two mouse strains (C57BL/6 and BALB/c) which are considered as prototypical of Th1 and Th2 immune response, respectively. RESULTS: ME obtained from seed kernel of unripe Azadirachta indica fruits decreased by about 30% the proportion of erythrocytes infected with the malaria parasite in C57BL/6 mice in the 4 days suppressive test. In this treatment group, MMP-9 and TNF levels were notably higher than those measured in the same mouse strain treated with the anti-malarial drug artesunate, Azadirachta indica kernel extracts from ripe fruits or solvent. In BALB/c mice, treatment with kernel extracts did not influence parasitaemia. MMP-9 and TNF levels measured in this mouse strain were notably lower than those recorded in C57BL/6 mice and did not vary among treatment groups. CONCLUSIONS: The effects of the ME on the parasite-host interactions appeared to be mouse strain-dependent, but also related to the ripening stage of the neem fruits, as only the unripe fruit seed kernel extracts displayed appreciable bioactivity.