Juniper (Juniperus communis L.) berries are widely used as a culinary spice and flavoring ingredient. While their volatile profile is well characterized, much less is known about the composition and biological activity of their nonvolatile constituents. Here, we show that a commercial carbonic extract prepared from juniper berry seasoning displays positive allosteric modulator (PAM)-like activity at the cannabinoid type-1 receptor (CB1R). Bioactivity-guided fractionation identified deoxypodophyllotoxin as a principal contributor to this effect. In the presence of a CB1R orthosteric agonist, this cyclolignan enhanced cAMP- and ERK-dependent signaling and β-arrestin recruitment, supporting a modulatory interaction with CB1R. Oral administration of the seasoning extract and related cyclolignans altered murine nociceptive responses without impairing motor coordination. These findings identify deoxypodophyllotoxin as a food-derived CB1R modulator and suggest that nonvolatile constituents of juniper berries may contribute to sensory responses associated with food consumption.

The development of advanced cell culture models has overcome the limitations of conventional monolayer cultures, still doubts remain about the reliability of data obtained using traditional systems, as well as the comparability of results from different models. This is highly relevant to preclinical drug analysis, where in vitro studies determine the fate of molecules. We investigated the molecular mechanisms that regulate the activity of cannabidiolic acid (CBDA) in a 3D model of a glioblastoma cell line, comparing the results with those obtained on a conventional monolayer model of the same cells. CBDA targeted the translation initiation factor EIF2A in both tested models. However, the downstream consequences of the CBDA-EIF2A interaction differed between cells cultured in 3D and 2D, since the biological functions and interactome of EIF2A were found to change significantly. Overall, this study sheds new light on the difficulties associated with comparing results obtained using different in vitro models.

Human dihydroorotate dehydrogenase (hDHODH), catalyzing the rate-limiting step of the pyrimidine biosynthesis pathway (PBP), is a drug target extensively investigated for various diseases including cancer, autoimmune disorders, and viral infections. We present evidence that the heterodimeric phloroglucinylpyrone arzanol potently inhibits hDHODH by competing with ubiquinone for binding to the lipophilic patch (LP) of the enzyme. Co-crystallization experiments on the enzyme-arzanol complex provided further insights into the binding pocket of hDHODH, revealing detailed features that could inspire the design of innovative inhibitors. The cellular translation of these enzymatic and biochemical data was validated in antiviral assays on SARS-CoV-2 infected cells. Taken together, these results exemplify the potential of natural products to explore novel areas of the protein druggable space and provide information relevant to multiple critical areas of drug discovery.

Cannabidiol (CBD) and cannabidivarin (CBDV) have shown promising clinical efficacy for the management of epilepsy, and beneficial effects have been demonstrated for CBD in a diversity of other pathologies (pain, schizophrenia, Tourette syndrome, anxiety). However, the mechanism(s) involved are still largely elusive, as are the molecular target(s) involved. CBD and CBDV do not orthosterically bind the cannabinoid type-1 (CB1) and type-2 (CB2) receptors, showing only modest allosteric modulation of both end-points. CBD and CBDV are biosynthesized as optically highly pure (-)-enantiomers, and most bioactivity data refer to these forms. (+)-CBD and related analogues [(+)-cannabidiolic acid (CBDA), its esters, and (+)-CBDV] can be obtained by chemical synthesis, and we present evidence that the (+)- and (-)-enantiomers of CBD, CBDV and of a selection of derivatives of CBDA have distinct binding profiles and functional activity at the CB1/CB2 receptors. Thus, with the single exception of the methyl ester of CBDA, all the (+)-enantiomers showed higher affinities than the (-)-isomers for both receptors, in particular for the CB2 receptors. The affinity of the (+)-enantiomers for both CB1 and CB2 receptors showed a marked dependence on the nature of the alkyl residue on the aromatic ring and the esterification pattern of CBDA. Potency was rarely in the low nM value for CB1, but generally so for CB2. Enantiomers showing low nM activity were further investigated for their intrinsic activity using GTP gamma S binding assays. This proved that (+)-CBD, (+)-CBDV and the methyl ester of (+)-CBDA are agonists at the CB2 receptor, with the beta-hydroxyethyl ester of (+)-CBDA being an inverse agonist, and its beta-hydroxypentyl ester behaving as an agonist at CB1 and an inverse agonist at CB2. Finally, we assayed in vitro the anti-inflammatory and neuroprotective properties of three compounds [(+)-CBD, (+)-CBDV and (+)-CBDA methyl ester] strongly activating CB2, showing their ability to reduce the production of proinflammatory factors and protecting neurons against their toxicity. Remarkably, these benefits were eliminated by the selective blockade of the CB2 receptor,

The berries of Piper borbonense (Miq.) C. DC., a wild vine native to Madagascar, are prized for their distinctive aroma and flavor, considered superior to the ones of the domesticated peppers (P. nigrum L., P. longum L.). The scarcity of studies on P. borbonense, locally known as voatsipérifery, makes it difficult to secure the identity of its berries and complement its sensory analysis. This supports the need for a comprehensive phytochemical investigation utilizing complementary analytical techniques. Headspace gas chromatography highlighted differences in the "volatilome" of P. borbonense and P. nigrum, while an untargeted metabolomic analysis, based on the LC-MS2-based feature-based molecular networking tool, annotated different classes of compounds (monoterpenoids, sesquiterpenoids, monolignols, lignans, and piperamides). This analysis next guided the isolation of 40 fully characterized compounds, including two new natural products [the sesquiterpene lactone 4-hydroxyisogelehomanolide (29) and the hydroxycinnamate ester borbonensin (38)]. The phytochemical profile of voatsipérifery is remarkable for the presence of the nonvolatile monoterpene p-menth-5-en-1,2-diol (23), of sesquiterpene lactones, and of large amounts of sesamin (34), a marker trait that clearly distinguishes it from those of the cultivated peppers of commerce and was confirmed with a parallel investigation of P. nigrum. Overall, our study underlines the relevance of advanced metabolomic approaches to characterize the phytochemical profile of spices and identify specific marker compounds.

Phytocannabinoids (pCBs) from Cannabis sativa represent an important class of bioactive molecules, potentially useful for the treatment of a wide range of diseases. Their efficacy is due to their ability to interact with multiple targets of the endocannabinoid system, including the thermosensitive transient receptor potential (Thermo-TRPs), namely TRPV1-4, TRPA1, and TRPM8 channels. Previously, we demonstrated a shift in selectivity toward TRPA1 in the activity profile of the main pCBs, that is, CBD, ∆8-THC, CBG, CBC, and CBN, by swapping the pentyl chain with the α,α-dimethylheptyl (DMH) one. Using these derivatives as a starting point, here we investigate the effects on the thermo-TRPs activity profile of the integration of a quinone group into the resorcinol scaffold. We found that, while the activity on TRPA1 is substantially retained, an increase in potency/efficacy on the TRPV3 modulation is observed. Docking studies were used to elucidate the binding modes of the most active compounds toward this receptor, providing a rationale for this biological activity. In summary, we show that the quinone derivatives of DMH-pCBs are endowed with a TRPA1/TRPV3 desensitizing activity, potentially useful for the treatment of skin diseases sustained by inflammatory conditions.

Eukaryotic Initiation Translation Factor 2A (EIF2A) is considered to be primarily responsible for the initiation of translation when a cell is subjected to stressful conditions. However, information regarding this protein is still incomplete. Using a combination of proteomic approaches, we demonstrated that EIF2A is the molecular target of the naturally occurring bioactive compound cannabidiolic acid (CBDA) within human glioblastoma cells. This finding allowed us to undertake a study aimed at obtaining further information on the functions that EIF2A plays in tumor cells. Indeed, our data showed that CBDA is able to activate EIF2A when the cells are in no-stress conditions. It induces conformational changes in the protein structure, thus increasing EIF2A affinity towards the proteins participating in the Eukaryotic Translation Machinery. Consequently, following glioblastoma cells incubation with CBDA we observed an enhanced neosynthesis of proteins involved in the stress response, nucleic acid translation and organization, and protein catabolism. These changes in gene expression resulted in increased levels of ubiquitinated proteins and accumulation of the autophagosome. Our results, in addition to shedding light on the molecular mechanism underlying the biological effect of a phytocannabinoid in cancer cells, demonstrated that EIF2A plays a critical role in regulation of protein homeostasis.

The optical purity of cannabichromene (CBC, 1a) is affected by the matrix in which it is generated by thermolysis from its native carboxylated form (cannabichromenic acid, CBCA, 1b). Thus, thermolysis at 130 °C in planta caused a marked decrease of the enantiomeric excess (ee), while, under the same conditions, only a modest decrease of optical purity was observed when thermolysis was carried out in extracto. To rationalize these puzzling observations, the kinetics of thermal (100 °C) racemization of enantiopure cannabichromene (1a) was evaluated by enantioselective ultrahigh performance liquid chromatography in solvents (decalin and isopropyl alcohol, neat and acidified with TFA) and surfaces (native and silanized borosilicate glass) of complementary polarity. Optical stability was more than halved in isopropanol compared to decalin (t1/2 50 h vs 135 h), but acidification had no effect on racemization. However, contact with a solid surface dramatically accelerated the process, with a t1/2 of only 6 h on both glass surfaces. The overall extent of racemization of enantiopure CBC (1a) was compared under conditions commonly used for decarboxylation (heating at 130 °C) between a decalin solution and a thin film on three different surfaces (native and silanized borosilicate glass and powdered blank cannabis biomass). In line with the kinetic data, a significant erosion of enantiopurity was observed on all solid surfaces compared to the solution. These observations suggest that discrepancies in the reported enantiomeric purity of natural CBC could be not only of biogenetic derivation but also be associated with the decarboxylation protocol of cannabichromenic acid (1b). These findings, while relevant for the exploitation of the bioactivity of natural CBC for human health, should also prompt the adoption of a standardized decarboxylation protocol for the studies on the configurational status of CBC (1a) in cannabis and, in general, of cannabinochromanoids in nature.

Melanoma is a skin cancer caused by the malignant transformation of melanocytes and cutaneous melanoma represents the most aggressive and deadliest type of skin cancer with an increasing incidence worldwide. The main purpose of the present research was to evaluate the anticancer effects of the natural bioactive compounds xanthomicrol (XAN) and eupatilin (EUP) in human A375 malignant skin melanoma cells, a cell line widely used as an in vitro model of cutaneous melanoma. XAN and EUP are lipophilic methoxylated flavones with antioxidant, anti-inflammatory, and antitumor properties. The effects of XAN and EUP on cell viability, morphology, lipid profile, oxidative status, apoptosis, and mitochondrial membrane polarization were determined and compared in A375 cells. At 24 h-incubation (MTT assay), XAN significantly reduced viability at the dose range of 2.5–200 μM, while EUP showed a significant cytotoxicity from 25 μM. Moreover, both methoxylated flavones induced (at 10 and 25 μM, 24 h-incubation) marked cell morphological alterations (presence of rounded and multi-nucleated cells), signs of apoptosis (NucView 488 assay), and a noteworthy mitochondrial membrane depolarization (MitoView 633 assay), coupled to a marked lipid profile modulation, including variations in the ratio of phospholipid/cholesterol and a decrease in the oleic, palmitic, and palmitoleic acid amounts. Moreover, a remarkable time-dependent ROS generation (2′,7′-dichlorodihydrofluorescein diacetate assay) was observed during 3 h-incubation of A375 cancer cells in the presence of XAN and EUP (10 and 25 μM). Our results confirm the potential antitumor effect of natural EUP and XAN in cutaneous melanoma by the activation of multiple anticancer mechanisms.

Background Tigilanol tiglate (TT) is a protein kinase C (PKC)/C1 domain activator currently being developed as an intralesional agent for the treatment of various (sub)cutaneous malignancies. Previous work has shown that intratumoral (I.T.) injection of TT causes vascular disruption with concomitant tumor ablation in several preclinical models of cancer, in addition to various (sub)cutaneous tumors presenting in the veterinary clinic. TT has completed Phase I dose escalation trials, with some patients showing signs of abscopal effects. However, the exact molecular details underpinning its mechanism of action (MoA), together with its immunotherapeutic potential in oncology remain unclear.Methods A combination of microscopy, luciferase assays, immunofluorescence, immunoblotting, subcellular fractionation, intracellular ATP assays, phagocytosis assays and mixed lymphocyte reactions were used to probe the MoA of TT in vitro. In vivo studies with TT used MM649 xenograft, CT-26 and immune checkpoint inhibitor refractory B16-F10-OVA tumor bearing mice, the latter with or without anti-programmed cell death 1 (PD-1)/anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) mAb treatment. The effect of TT at injected and non-injected tumors was also assessed.Results Here, we show that TT induces the death of endothelial and cancer cells at therapeutically relevant concentrations via a caspase/gasdermin E-dependent pyroptopic pathway. At therapeutic doses, our data demonstrate that TT acts as a lipotoxin, binding to and promoting mitochondrial/endoplasmic reticulum (ER) dysfunction (leading to unfolded protein responsemt/ER upregulation) with subsequent ATP depletion, organelle swelling, caspase activation, gasdermin E cleavage and induction of terminal necrosis. Consistent with binding to ER membranes, we found that TT treatment promoted activation of the integrated stress response together with the release/externalization of damage-associated molecular patterns (HMGB1, ATP, calreticulin) from cancer cells in vitro and in vivo, characteristics indicative of immunogenic cell death (ICD). Confirmation of ICD in vivo was obtained through vaccination and rechallenge experiments using CT-26 colon carcinoma tumor bearing mice. Furthermore, TT also reduced tumor volume, induced immune cell infiltration, as well as improved survival in B16-F10-OVA tumor bearing mice when combined with immune checkpoint blockade.Conclusions These data demonstrate that TT is an oncolytic small molecule with multiple targets and confirms that cell death induced by this compound has the potential to augment antitumor responses to immunotherapy.

The distribution, chemistry, and molecular bioactivity of tiglianes are reviewed from the very beginning of the studies on these diterpenoids, summarizing their clinical and toxicological literature mostly in its more recent and controversial aspects, and critically analyzing various proposals for their biosynthesis.

Musk yarrow (Achillea erba-rotta subsp. moschata (Wulfen) I. Richardson) is endemic to the Central Alps, and is used to flavour alcoholic beverages. Despite its popularity as aromatizing agent and its alleged beneficial effects on digestion, the phytochemical profile of the plant is still largely unknown and undiscovered. As a consequence, its authentication in aromatized products is impossible beyond sensory analysis allowing forgery. To address these issues, we phytochemically characterized a sample of musk yarrow from the Italian Eastern Alps, identifying, in addition to widespread phytochemicals (taraxasterol, apigenin), the guaianolides 3, 8, 9; the seco-caryophyllane 6; and the polymethoxylated lipophilic flavonoids 1, 4, and 5. The flavonoid xanthomicrol 1, a major constituent of the plant, was cytotoxic to HeLa cells, but only modestly affected primary 3T3 fibroblasts. On account of their stability, detectability by UV absorption, and concentration, the oxygenated flavonoids qualify as markers to validate the supply chain of the plant growers to consumers.

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-β-diketone system to trigger complex skeletal rearrangements and pave the way to new areas of the natural products chemical space.

Despite their early discovery, the bioactivity of acidic cannabinoids was long overlooked. Issues of stability and a pharmacological focus on Δ9-THC and its biological profile combined to relegate the non-narcotic native form of phytocannabinoids to a sort of investigational limbo. Recent studies have disclosed an attractive bioactivity profile for specific acidic phytocannabinoids but concerns about their limited stability have remained substantially unaddressed. To solve this issue, we have developed the hydroxamate derivatives of Δ8-tetrahydrocannabinolic acid-A (Δ8-THCA-AH, 6) and cannabidiolic acid (CBDAH, 5) as novel acidic cannabinoid bioisosteres, and we report here their synthesis and bioactivity profile against specific cannabinoid targets, as well as promising in vivo activity in a murine model of polycystic ovary syndrome (PCOS) associated with obesity.

Skin oxidative stress results in structural damage, leading to premature senescence, and pathological conditions such as inflammation and cancer. The plant-derived prenylated pyrone-phloroglucinol heterodimer arzanol, isolated from Helichrysum italicum ssp. microphyllum (Willd.) Nyman aerial parts, exhibits anti-inflammatory, anticancer, antimicrobial, and antioxidant activities. This study explored the arzanol protection against hydrogen peroxide (H2O2) induced oxidative damage in HaCaT human keratinocytes in terms of its ability to counteract cytotoxicity, reactive oxygen species (ROS) generation, apoptosis, and mitochondrial membrane depolarization. Arzanol safety on HaCaT cells was preliminarily examined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and microscopic observation. The arzanol pre-incubation (5-100 μM, for 24 h) did not induce cytotoxicity and morphological alterations. The phloroglucinol, at 50 μM, significantly protected keratinocytes against cytotoxicity induced by 2 h-incubation with 2.5 and 5 mM H2O2, decreased cell ROS production induced by 1 h-exposure to all tested H2O2 concentrations (0.5-5 mM), as determined by the 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA) assay, and lipid peroxidation (thiobarbituric acid reactive substances [TBARS] method). The 2-h incubation of keratinocytes with H2O2 determined a significant increase of apoptotic cells versus control cells, evaluated by NucView® 488 assay, from the dose of 2.5 mM. Moreover, an evident mitochondrial membrane potential depolarization, monitored by fluorescent mitochondrial dye MitoView™ 633, was assessed at 5 mM H2O2. Arzanol pre-treatment (50 μM) exerted a strong significant protective effect against apoptosis, preserving the mitochondrial membrane potential of HaCaT cells at the highest H2O2 concentrations. Our results validate arzanol as an antioxidant agent for the prevention/treatment of skin oxidative-related disorders, qualifying its potential use for cosmeceutical and pharmaceutical applications.

Covering: up to the end of 2022The area of scalemic natural products is often enigmatic from a mechanistic standpoint, since low optical purity is observed in compounds having multiple contiguous stereogenic centers resulting from mechanistically distinct biogenetic steps. A scalemic state is rarely the result of a sloppy enzymatic activity, rather resulting from the expression of antipodal enzymes/directing proteins or from the erosion of optical purity by enzymatic or spontaneous reactions. Evidence for these processes is critically reviewed, identifying the mechanisms most often associated to the enzymatic generation of scalemic natural products and also discussing analytical exploitations of natural products' scalemicity.

Cannabichromene (CBC, 1a) occurs in Cannabis (Cannabis sativa) as a scalemate having a composition that is strain-dependent in terms of both enantiomeric excess and enantiomeric dominance. In the present work, the chirality of CBC (1a), a noncrystalline compound, was shown not to be significantly affected by standard conditions of isolation and purification, and enantiomeric self-disproportionation effects were minimized by carrying out the chiral analysis on crude fractions rather than on purified products. A genetic basis for the different enantiomeric state of CBC in Cannabis therefore seems to exist, implying that the chirality status of natural CBC (1a) in the plant is associated with the differential expression of CBCA-synthase isoforms and/or of associated directing proteins with antipodal enantiospecificity. The biological profile of both enantiomers of CBC should therefore be investigated independently to assess the contribution of this compound to the activity of Cannabis preparations.