Biological Properties of Oleanolic Acid Derivatives Bearing Functionalized Side Chains at C-3.

Triterpene acids are a class of pentacyclic natural carboxylic compounds endowed with a variety of biological activities including antitumor, antimicrobial, and hepatoprotective effects. In this work, several oleanolic acid derivatives were synthesized by structurally modifying them on the C-3 position. All synthesized derivatives were evaluated for possible antibacterial and antiviral activity, and among all the epimers, 6 and 7 demonstrated the best biological activities. Zone-of-inhibition analyses were conducted against two strains, E. coli as a Gram-negative and S. aureus as a Gram-positive model. Subsequently, experiments were performed using the microdilution method to determine the minimum inhibitory concentration (MIC). The results showed that only the derivative with reduced hydrogen bonding ability on ring A possesses remarkable activity toward E. coli. The conversion from acid to methyl ester implies a loss of activity, probably due to a reduced affinity with the bacterial membrane. Before the antiviral activity, the cytotoxicity of triterpenes was evaluated through a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Samples 6 and 7 showed less than 50% cytotoxicity at 0.625 and 1 mg/mL, respectively. The antiviral activity against SARS-CoV-2 and PV-1 did not indicate that triterpene acids had any inhibitory capacity in the sub-toxic concentration range.

The essential oil chemical composition of a rare ethnopharmacoligical plant: Verbascum creticum (L.) Cav.

The genus Verbascum L, belonging to the Scrophulariaceae family, is native to Europe, Africa and Asia. The use of plants of this genus in the popular medicine has been largely reported. In the present study the chemical composition of the essential oil from aerial parts of Verbascum creticum (L.) Cav., a rare plant, never previously investigated, known for its anti-inflammatory properties of the intestinal mucosa and in the treatment of acute and chronic catarrhs, growing in Algeria, Baleares, Calabria, Sardinia, Sicily, Spain and Tunisia, was evaluated by GC-MS. The main components of its essential oil (Vc) were 1-octen-3-ol (23.9%), cis-3-hexen-1-ol (9.4%), phenylethanal (4.6%), and 2-methyl-benzofurane (4.6%). The comparison with all the other studied essential oils of genus Verbascum is discussed. Furthermore, a review of the use of the Verbascum species in the popular medicine has been carried out.

The essential oil chemical composition of a sicilian (Italy) accession of Doronicum caucasicum M. Bieb.

Doronicum is a relatively small genus belonging to the tribe Senecioneae (Fam. Asteraceae), distributed in Asia, Europe, and North Africa. Some of its species are considered toxic due to the presence of pyrrolizidine alkaloids whereas some other ones are largely utilised in the ethnopharmacology of several countries. In the present study, the essential oil composition of a Sicilian accession of Doronicum caucasicum M. Bieb (syn. D. orientale Hoffm.), not previously investigated, is particularly rich in sesquiterpene hydrocarbons (80.3%) with germacrene D (58.9%), α-humulene (8.8%), and ß-caryophyllene (6.5%) as main metabolites. A comparison with all the essential oils from Doronicum taxa studied so far has been carried out.

Chemical Characterization, Free Radical Scavenging, and Cellular Antioxidant Properties of the Egadi Island Endemic Brassica macrocarpa Guss Leaf Extract.

The genus Brassica is an important source of food in the Mediterranean diet with documented nutritional and medicinal properties. However, few studies have investigated the phytochemical composition and the biological activity of wild Sicilian taxa. Thus, we aimed to study the chemical profile and the antioxidant potential, in vitro and in LPS-stimulated RAW 264.7 cells, of a methanolic extract of leaves of wild Brassica macrocarpa Guss (B. macrocarpa) (Egadi Islands; Sicily-Italy). B. macrocarpa methanolic extract showed a large amount of glucosinolates and different phenolic compounds. It exhibited antioxidant activity in the DPPH assay and in LPS-stimulated RAW 264.7 cells, being able to reduce NO and ROS levels and NOS2 mRNA expression. Our study demonstrated that Sicilian B. macrocarpa methanolic extract, in LPS-stimulated macrophages, efficiently counteracts oxidative stress and displays radical scavenging activity. Future studies are required to identify the contribution of the single phytocomponents, to characterize the action mechanism, and to reveal possible applications in human health.

Stachys durandiana Coss., an endemic plant of Morocco: chemical composition of its aerial parts essential oil.

The genus Stachys L. (Lamiaceae) comprises more than 300 species as annual or perennial herbs or small shrubs, spread in temperate regions of Mediterranean, Asia, America, and Southern Africa and several species have been used in the traditional medicine of many countries. Section Stachys, one of nineteen sections of genus Stachys, is divided in two subsections: Sylvaticae and Circinatae. In the present study the chemical composition of the essential oil from aerial parts of Stachys durandiana Coss., endemic of Morocco, and belonging to subsection Circinatae, was analysed by GC-MS. No report has been previously published on this species. The result showed the presence of large quantity of monoterpene hydrocarbons (73.3%), being α-pinene (38.0%) ß-pinene (14.8%), and limonene (11.1%) the principal constituents. Furthermore, a complete review on the chemical composition and biological properties of all the other Stachys taxa, belonging to section Stachys, studied so far, was carried out.

Cladanthus scariosus Essential Oil and Its Principal Constituents with Cytotoxic Effects on Human Tumor Cell Lines.

Cladanthus is a small genus of the Asteraceae family comprising just five species that, apart from Cladanthus mixtus (L.) Chevall., has a large distribution in all the Mediterranean countries, mainly in the North Africa area. Several ethnopharmacological uses have been reported for species of this genus. Notably, Cladanthus scariosus (Ball) Oberpr. & Vogt is endemic to Morocco. Seeking to delve deeper into the phytochemistry and pharmacological aspects of this species, in this work, we investigated the essential oil (EO) obtained from the aerial parts of a locally sourced accession, hitherto unexplored, growing wild near Tizi n'Ticha, Morocco. The chemical composition of the EO, obtained by the hydrodistillation method, was evaluated by GC and GC-MS. The most abundant EO constituent was germacrene D (13.2%), the principal representative of the sesquiterpene hydrocarbons class (27.2%). However, the major class of constituents was monoterpene hydrocarbons (43.0%), with α-pinene (11.9%), sabinene (10.2%), p-cymene (8.5%), and α-phellandrene (5.2%) as the most abundant. The EO and its main constituents have been tested for their possible cytotoxic activity against three human tumor cell lines (MDA-MB 231, A375, and CaCo2) using the MTT assay, with corresponding IC50 values of 13.69, 13.21, and 22.71 µg/mL, respectively. Germacrene D and terpinen-4-ol were found to be the most active constituents with IC50 values between 3.21 and 9.53 µg/mL. The results demonstrate remarkable cytotoxic activity against the three human tumor cell lines studied, and in the future, further analyses could demonstrate the excellent potential of C. scariosus EO as an antitumor agent.

Chemical Profile and Healthy Properties of Sicilian Diplotaxis harra subsp. crassifolia (Raf.) Maire.

This study was aimed at investigating the phytochemical profile and bioactivity of Diplotaxis harra subsp. crassifolia (Brassicaceae), a species from central-southern Sicily (Italy), where it is consumed as a salad. For this purpose, LC-ESI/HRMSn analysis of the ethanolic extract was performed, highlighting the occurrence, along with flavonoids, hydroxycinnamic acid derivatives, and oxylipins, of sulfated secondary metabolites, including glucosinolates and various sulfooxy derivatives (e.g., C13 nor-isoprenoids, hydroxyphenyl, and hydroxybenzoic acid derivatives), most of which were never reported before in the Brassicaeae family or in the Diplotaxis genus. Following ethnomedicinal information regarding this species used for the treatment of various pathologies such as diabetes and hypercholesterolemia, D. harra ethanolic extract was evaluated for its antioxidant potential using different in vitro tests such as 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), Ferric Reducing Ability Power, and ß-carotene bleaching tests. The inhibitory activity of carbohydrate-hydrolyzing enzymes (α-amylase and α-glucosidase) and pancreatic lipase was also assessed. In the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid assay, an IC50 value comparable to the positive control ascorbic acid (2.87 vs. 1.70 µg/mL, respectively) was obtained. The wild-wall rocket salad extract showed a significant α-amylase inhibitory effect. Obtained results indicate that Sicilian wild-wall rocket contains phytochemicals that can prevent hyperglycemia, hyperlipidemia, and obesity.

Screening of the essential oil of Thapsia garganica subsp. messanensis (Guss.) Brullo & al., an endemic plant of Sicily (Italy).

The genus Thapsia L., belonging to the Scandiceae tribe of the Apiaceae family, is mainly distributed in the Mediterranean area, North Africa, and the Iberian Peninsula. The use of plants of this genus in popular medicine dates back to the age of ancient Greeks. In the present study the chemical composition of the essential oil from aerial parts of Thapsia garganica subsp. messanensis (Guss.) Brullo & al., an endemic plant of Sicily, never previously investigated, was evaluated by GC-MS. The main components of its essential oil (Tgm) were 1,4-dimethylazulene (17.0%), chamazulene (10.1%), 3-methyl nonane (7.0%), and butyl heptanoate (4.6%). The comparison with all the other studied essential oils of the genus Thapsia is discussed.

Paeonia mascula subsp. russoi (biv.) Cullen & Heywood: the chemical composition of the aerial parts essential oils of two different populations collected in Sicily (Italy).

In the present study, the chemical composition of the essential oil from aerial parts of two populations of Paeonia mascula subsp. russoi, collected in Sicily, was evaluated by GC-MS. No previously phytochemical investigation has been reported for this subspecies. The main components of the essential oil of the population with pink flowers were salicylaldehyde (34.31%), nonanal (16.95%) and 2-hexenal (10.17%), whereas essential oil of the population with white flowers, was shown to be rich of myrtanal (14.14%), eugenol (14.02%) and salicylaldehyde (12.21%). Furthermore, a complete literature review, not present in literature, on the composition of the essential oils of all the other taxa of Paeonia, studied so far, was performed. PCA and HCA analyses of the composition of essential oils obtained from the aerial parts were also carried out.

The essential oil composition of Phlomis bovei subsp. maroccana Maire, an endemic species of Morocco.

Phlomis L. is a genus belonging to the Lamiaceae family, distributed in Macaronesia, the Mediterranean basin, Northeast Africa, Central Asia, and Western Himalaya. Plants of this genus are used against various diseases in the ethno-medicine of several countries and some of them are also utilised for culinary purposes. In the present study, the essential oil chemical composition of the aerial parts of Phlomis bovei subsp. maroccana Maire, an endemic species of Morocco, was analysed by GC-MS. No previous paper has been previously published on this taxon. Main constituents of the essential oil were sesquiterpene hydrocarbons (44.48%) with curcumene (11.20%), a very rare compound in Phlomis essential oils, ß-himachalene (6.22%), and ß-cedrene (3.81%) as principal metabolites. 1-hexadecanol (7.75%) and 1-octadecanol (5.32%) were the main constituents among the alcohols (19.66%). A comparison with all the other essential oils from Phlomis taxa has been carried out.

Synthetic Derivatives of Natural ent-Kaurane Atractyligenin Disclose Anticancer Properties in Colon Cancer Cells, Triggering Apoptotic Cell Demise.

The antitumor activity of different ent-kaurane diterpenes has been extensively studied. Several investigations have demonstrated the excellent antitumor activity of synthetic derivatives of the diterpene atractyligenin. In this research, a series of new synthetic amides and their 15,19-di-oxo analogues obtained from atractyligenin by modifying the C-2, C-15, and C-19 positions were designed in order to dispose of a set of derivatives with different substitutions at the amidic nitrogen. Using different concentrations of the obtained compounds (10-300 µM) a reduction in cell viability of HCT116 colon cancer cells was observed at 48 h of treatment. All the di-oxidized compounds were more effective than their alcoholic precursors. The di-oxidized compounds had already reduced the viability of two colon cancer cells (HCT116 and Caco-2) at 24 h when used at low doses (2.5-15 µM), while they turned out to be poorly effective in differentiated Caco-2 cells, a model of polarized enterocytes. The data reported here provide evidence that di-oxidized compounds induced apoptotic cell death, as demonstrated by the appearance of condensed and fragmented DNA in treated cells, as well as the activation of caspase-3 and fragmentation of its target PARP-1.

Phytochemical Characterization, Antioxidant, and Anti-Proliferative Activities of Wild and Cultivated Nigella damascena Species Collected in Sicily (Italy).

The use of Nigella damascena seeds in the culinary field or as aerial parts infusions in the pharmaceutical and cosmetic fields is widely reported. The biological activity of this plant, as demonstrated over the years, is closely related to its phytochemical content. This investigation focused on the comparative study of the same plants of N. damascena, one totally wild (WND), while the other two, one with white flowers (CWND) and the other with blue flowers (CBND), were subject to cultivation, irrigation, and manual weeding. Using the potential of 1D and 2D-NMR spectroscopy, coupled with MS/MS spectrometric studies, the three methanolic extracts of N. damascena were investigated. Chemical studies have highlighted the presence of triterpene saponin compounds and various glycosylated flavonoids. Finally, the in vitro antiproliferative and antioxidant activities of the three individual extracts were evaluated. The antiproliferative activity performed on U-937, HL-60, and MCF-7 tumor cell lines highlighted a greater anticancer effect of the CBND and CWND extracts compared to the data obtained using WND. The antioxidant activity, however, performed to quantify ROS generation is comparable among the extracts used.

The chemical composition of the aerial parts' essential oil of Limonium lobatum (L.f.) Chaz. growing wild in Algeria.

The Limonium genus (Plumbaginaceae) includes several species of perennial herbs and shrubs belonging to a particular type of halophytes, known as 'recretohalophytes'. Limonium species are widely distributed in the Mediterranean region, mainly in the North-Eastern and Southern countries and several bioactivities have been well documented. In the present study, the chemical composition of the essential oil (EO) of the aerial parts of Limonium lobatum (L.f.) Chaz., a species never chemically previously studied and collected in Algeria, which grows in South Spain, North Africa, and SW Asia, was analysed using GC-MS. The main constituents of the EO were monoterpenes involving eucalyptol (14.21%), ß-pinene (8.62%), ß-myrcene (8.18%). Among the sesquiterpene compounds ß-caryophyllene (8.94%) was the major one. The chemical profile of the EO presented here was compared with the EOs of previously investigated Limonium taxa. Furthermore, a complete literature review on the ethno-pharmacological uses of Limonium species was performed.

Phytochemical profile, in vitro antioxidant and antibacterial activities of different extracts of an Algerian endemic: Teucrium atratum.

Teucrium atratum Pomel. is a species belonging to the Lamiaceae family used in Algerian folk medicine. The present work essentially aimed to assess the phenolic composition and to evaluate some of the biological effects of different extracts, never previously studied, of T. atratum growing in Algeria. High levels of total phenolic and flavonoids were recorded in the hydromethanolic extract. Chlorogenic acid, isoquercetin, coumarin, cinnamic acid, quercetin dihydrate, and catechin were identified in the methanolic extract by mean of HPLC. The antioxidant activity assessed showed that the methanolic extract was the most active, while, the hydromethanolic extract showed a great power to reduce iron. In addition, all extracts had a significant antibacterial effect against the four tested bacterial strains, with Staphylococcus aureus as the most sensitive one. These findings can be a starting point to evaluate the plant as a source of natural bioactive compounds with antioxidant and antibacterial effects.

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).

Seseli tortuosum L. subsp. tortuosum Essential Oils and Their Principal Constituents as Anticancer Agents.

Seseli tortuosum L. subsp. tortuosum, belonging to the Apiaceae family, is a species that grows in Europe, mainly in the Mediterranean regions. The history of its application in traditional medicine highlights its various biological properties. Trying to explore the phytochemistry and pharmacological aspects of this species, the essential oils (EOs) extracted from flowers, stems, and roots of a locally wild accession, never previously investigated, growing in Sicily, Italy, were investigated. The chemical composition of all EOs, obtained by the hydrodistillation method, was evaluated by GC-MS. The most abundant class of all investigated samples was that of monoterpene hydrocarbons (79.98-91.21%) with p-cymene, α-pinene, ß-pinene, and ß-ocimene as major compounds. These EOs, and their main components, were tested for their possible anticancer activity. Obtained data provided evidence that among the different EOs tested, at the dose of 100 µg/mL, those extracted from stems and roots were particularly effective, already at 24 h of treatment, in reducing the cell viability of 42% and 95%, respectively, in HCT116 colon cancer cell line. These EOs also exerted a remarkable cytotoxic effect that was accompanied by morphological changes represented by cell shrinkage as well as a reduction in residual cell population. Differently, modest effects were found when EOs extracted from flowers were tested in the same experimental conditions. The evaluation of the phytocompounds mainly represented in the EOs extracted from different parts of the plant and tested in a range of concentrations between 20 and 200 µg/mL, revealed that α-pinene, ß-pinene, and p-cymene exerted only modest effects on cell viability. Differently, a remarkable effect was found when ß-ocimene, the most abundant phytocomponent in EOs from roots, was tested on colon cancer cells. This phytocompound, among those identified in EOs from Seseli tortuosum L. subsp. tortuosum, was found to be the most effective in reducing colon cancer cell viability with IC50 = 64.52 µg/mL at 24 h of treatment. All together, these data suggest that ß-ocimene could be responsible for the effects observed in colon cancer cells.

The chemical composition of the aerial parts' essential oil of matthiola fruticulosa (L.) maire growing in Sicily, Italy.

Matthiola Aiton is a genus belonging to the Brassicaceae family, distributed in Macaronesia, the Mediterranean basin, and the Saharo-Sindian region. Plants of this genus are used against various diseases in the ethno-medicine of several countries and a complete review of their usage has been carried out in this paper. In the present study, the essential oil chemical composition of the aerial parts of the Sicilian accession of Matthiola fruticulosa (L.) Maire, a species growing in South-Western Europe, Northern Africa, and Western Asia, was analysed by GC and GC-MS. No previous paper has been previously published on the essential oil of this species. Main constituents of the oil were sulphur compounds (45.5%) with the two quite rare cis and trans isomers of 5-(methylthio)-4-pentenenitrile as principal metabolites (16.3% and 10.7%, respectively). Principal compound of the oil was the diterpene phytol (16.5%) whereas other terpenoids were less abundant (10.6%).

The chemical composition of the aerial parts essential oils of Centaurea erycina (Asteraceae), an endemic species of Sicily (Italy).

In the present study, the chemical composition of the essential oil from aerial parts of a very rare Centaurea species, not previously investigated, Centaurea erycina Raimondo and Bancheva, collected in Sicily, was evaluated by GC-MS. The new species, classified just twenty years ago, belongs to Centaurea cineraria group (sect. Pannophyllum Hayek, Asteraceae) and grows in an extremely limited area in the NW part of Sicily. The oil was shown to be rich of aldehydes (41.4%) and sesquiterpenes (33.4%). The main components of the essential oil were ß-caryophyllene (13.4%), caryophyllene oxide (12.6%), hexanal (11.9%), and trans-2-hexenal (10.0%). Furthermore, a complete literature review on the composition of the essential oils of all the other taxa of Centaurea, belonging to sections Pannophyllum, studied so far, was carried out.

Phytochemical investigation and antitumor activity of coumarins from Sicilian accession of Ferulago nodosa (L.) Boiss. roots.

Ferulago nodosa (L.) Boiss. (Apiaceae) is a species occurring in the Balkan-Tyrrhenian area being present in Crete, Greece, Albania, and probably in Macedonia. From the roots of this accession of species, not previously investigated, four coumarins, grandivittin, aegelinol benzoate, felamidin and aegelinol, and two terpenoids, (2E)-3-methyl-4-[(3-methyl-1-oxo-2-buten-1yl)oxy]-2-butenoic acid and pressafonin-A, were isolated and spectroscopically characterized. The last one was never detected in Ferulago species. The evaluation of the anti-tumor effects of F. nodosa coumarins on colon cancer HCT116 cells showed only a modest effect on reduction of tumor cell viability. For aegelinol, the reduction of colon cancer cell viability already appears with 25 µΜ, while using 50 e 100 µM doses of marmesin the residual viability amounted to 70% and 54%, respectively. This effect resulted more evident at higher doses of compounds (at 200 µM from 80% to 0%). The most effective compounds resulted coumarins lacking ester group.

The chemical composition of the aerial parts' essential oil of Geocaryum capillifolium (Guss.) Coss growing in Sicily (Italy).

The three genera Geocaryum Coss., Conopodium W.D.J. Koch, and Bunium L. are closely related, and their correct identification is complex. The first two genera are distributed in Europe and North Africa, while several Bunium species also occur in Asia. In the present study, we analysed the chemical composition of the essential oil of the aerial parts of Geocaryum capillifolium (Guss.) Coss. a rare species collected in Sicily, which also grows in the Iberian Peninsula, Algeria, and Greece, was analysed using GC-MS. The main constituents of the essential oil were sesquiterpene hydrocarbons involving cis-ß-farnesene (31.2%), trans-ß-caryophyllene (20.0%), and germacrene D (8.5%). The chemical profile of the essential oil presented here was compared with the oils of previously investigated Geocaryum, Conopodium, and Bunium taxa, as reported in the literature. To the best of our knowledge, no report has been previously published about the essential oil of the Sicilian accession of this species.