Biological Activities of Sesquiterpene Lactones Isolated from the Genus Centaurea L. (Asteraceae)

Centaurea polyacantha and C. maroccana: the chemical composition of the aerial parts essential oils of these Centaurea species (Asteraceae) collected in Morocco

In the present study, the chemical composition of the essential oil from the aerial parts of two Centaurea species not previously investigated, C. polyacantha Willd. (sect. Seridia, Asteraceae) and C. maroccana Ball. (sect. Calcitrapa, Asteraceae), collected in Morocco, was evaluated by GC-MS. The main components of the essential oil of the first one were limonene (18.2%), β-bisabolene (11.5%), (Z)-β-farnesene (8.6%), and spathulenol (8.3%), whereas the C. maroccana essential oil, practically devoid of terpenoids, was shown to be rich in some unusual Centaurea metabolites: 1-hexadecanol (24.9%), docosane (23.7%), and 1-octadecanol (19.5%). Furthermore, a complete literature review on the composition of the essential oils of all the other taxa of Centaurea, belonging to sections Seridia and Calcitrapa, studied so far, was performed.

Disafynol: A polyacetylene dimer from Centaurea schmidii enhancing breast cancer cell apoptosis via oxidative and ER stress pathways

Phytochemical analysis of the aerial parts of Centaurea schmidii Wagenitz (Asteraceae) led to the isolation of disafynol, a novel polyacetylene, for the first time. This study investigated its anti-cancer effects and the mechanisms underlying these effects in MDA-MB-231 (estrogen receptor-negative) and MCF-7 (estrogen receptor-positive) breast cancer cell lines. The cytotoxic effects of disafynol were evaluated using various concentrations to measure cell viability, apoptosis, reactive oxygen species (ROS) levels, mitochondrial membrane potential (MMP), caspases-12/6 activity, and protein aggregation. Expression of apoptotic markers and endoplasmic reticulum (ER) stress-related genes was analyzed by western blot and reverse transcription-PCR analyses, respectively. Disafynol exhibited dose-dependent cytotoxicity, with greater potency in MDA-MB-231 cells (IC50: 10.6 µM) compared to MCF-7 cells (IC50: 30 µM), indicating hormone receptor-independent manner of cell growth inhibition. Treating cells with disafynol caused significant apoptosis, marked by enhanced ROS production and reduced MMP. Meanwhile, disafynol induced Bcl-2 downregulation, Bax upregulation, and caspase-12/6 activities in both breast cancer cells. Additionally, disafynol triggered ER stress, as evidenced by protein aggregation and upregulation of genes related to ER stress, including BIP, ATF4, CHOP, and XBP-1. Overall, disafynol demonstrates significant pro-apoptotic effects on breast cancer cells by inducing oxidative stress and activating the ER stress pathway. Its hormone receptor-independent cytotoxicity suggests potential therapeutic applications for treating breast cancers, including triple-negative subtypes.

Costunolide inhibits the progression of TPA-induced cell transformation and DMBA/TPA-induced skin carcinogenesis by regulation of AKT-mediated signaling

BACKGROUND

Costunolide (COS), a sesquiterpene lactone extracted from the roots of Saussurea costus, is known to possess anticancer properties in various cancers, including colon, oral, and lung cancers, but its mechanism of action in skin carcinogenesis has not yet been explored. Present study investigates the chemopreventive mechanism of COS on skin inflammation and carcinogenesis both in vitro and in vivo.

METHODS

The cytotoxicity of COS was examined on a normal murine epidermal cell line, JB6, by treating with COS using the WST-8 assay. Subsequently, the effect of COS on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced cellular transformation was assessed through a soft-agar assay. Furtherly, cell cycle and apoptosis analysis and the expression of related proteins were determined via flow cytometry and Western blotting, respectively. The effects of COS on tumor promotion induced by DMBA/TPA treatment and the underlying molecular mechanisms in mouse skin carcinogenesis were identified through H&E staining and immunohistochemical analysis.

RESULTS

COS significantly inhibited colony growth and number in TPA-induced JB6 cells transformation, arrested the cell cycle at the G2/M phase, increased p21 expression, and decreased cyclin B expression. In addition, COS induced cell apoptosis and increased the related markers expression including cleaved caspase-3 and - 7. COS suppressed the expression of phosphorylated AKT and its downstream signaling proteins and effectively reduced the translocation of phosphorylated NF-κB from the cytosol to the nucleus. Moreover, COS reduced papilloma formation in mouse skin and inhibited hyperplasia and phosphorylated AKT expression in tissues.

CONCLUSION

These results demonstrate that COS inhibits TPA-induced cellular transformation and skin carcinogenesis both in vitro and in vivo through the AKT signaling pathway. Our findings suggest the potential of COS as a chemopreventive agent for skin carcinogenesis, highlighting its significance for further investigation in cancer prevention and therapy.

Sesquiterpene Lactones as Promising Phytochemicals to Cease Metastatic Propagation of Cancer

Cancer metastasis remains the most challenging issue in cancer therapy. Recent reports show that cancer metastasis accounts for over 90% of cancer-associated deaths in the world. Metastasis is a multi-step process by which cancer cells spread to distant tissues and organs beyond the primary site. The metastatic propagation of different cancers is under the surveillance of several regulating processes and factors related to cellular signaling pathways. Plant-derived phytochemicals are bioactive components of plants with a variety of biological and medicinal activities. Several phytochemicals have been shown to target various molecular factors in cancer cells to tackle metastasis. Sesquiterpene lactones, as a diverse group of plant-derived phytochemicals with a variety of biological activities, have been shown to suppress the promotion and progression of different cancer types by acting on multiple cell-signaling pathways. This review article briefly describes the process of metastasis and its components. Then, sesquiterpene lactones with the ability to target and inhibit invasion, migration, and metastasis along with the molecular mechanisms of their effects on different cancers are described in detail.

A study on the antioxidant, anti-inflammatory, and xanthine oxidase inhibitory activity of the Artemisia vulgaris L. extract and its fractions

ETHNOPHARMACOLOGICAL RELEVANCE

Vietnamese people use mugwort (Artemisia vulgaris L.) to treat arthritis and gout. Our previous research shows that mugwort contains flavonoids, and its extract possesses antibacterial and anti-inflammatory activities. However, no publications have been on the xanthine oxidase inhibitory activity of mugwort and acute anti-inflammatory activity in vivo.

AIM OF THE STUDY

The study aimed to verify the antioxidant, xanthine oxidase inhibitory, and anti-inflammatory capabilities of mugwort extract in vitro and in vivo, isolate phyto-compounds from potential bioactive fractions, and then evaluate their potential in inhibiting xanthine oxidase.

METHODS

According to established methods, the extract and the active flavonoids were obtained using different chromatographic techniques. DPPH, ABTS, reducing power, and H2O2 elimination were used to evaluate antioxidant activity. The model of LPS-induced RAW264.7 cells was used to measure the inhibition of NO production. The carrageenan-induced paw oedema model was used to assess acute inflammation in mice. In vitro, xanthine oxidase inhibition assay was applied to investigate the effects of extract/compounds on uric acid production. Chemical structures were identified by spectral analysis.

RESULTS

The assessment of the acute inflammatory model in mice revealed that both the 96% ethanol and the 50% ethanol extracts significantly decreased oedema in the mice's feet following carrageenan-induced inflammation. 96% ethanol extract exhibited a better reduction in oedema at the low dose. The analysis revealed that the ethyl acetate fraction had the highest levels of total polyphenols and flavonoids. Additionally, this fraction demonstrated significant antioxidant activity in various assays, such as DPPH, ABTS, reducing power, and H2O2 removal. Furthermore, it displayed the most potent inhibition of xanthine oxidase, an anti-inflammatory activity. Five phytochemicals were isolated and determined from the active fraction such as luteolin (1), rutin (2), apigenin (3), myricetin (4), and quercetin (5). Except for rutin, the other compounds demonstrated the ability to inhibit effective xanthine oxidase compared to standard (allopurinol). Moreover, quercetin (5) inhibited NO production (IC50 21.87 μM).

CONCLUSION

The results indicate that extracts from A. vulgaris effectively suppressed the activity of xanthine oxidase and exhibited antioxidant and anti-inflammatory properties, potentially leading to a reduction in the production of uric acid in the body and eliminating ROS. The study identified mugwort extract and bioactive compounds derived from Artemisia vulgaris, specifically luteolin, apigenin, and quercetin, as promising xanthine oxidase inhibitors. These findings suggest that further development of these compounds is warranted. At the same time, the above results also strengthen the use of mugwort to treat gout disease in Vietnam.

Chemical Composition and Lipid Bioactive Components of Centaurea thracica Dwelling in Bulgaria

Centaurea thracica (Janka) Hayek is a plant common in southern Bulgaria. The inflorescences were collected during June and September 2021, while their seeds were obtained in September 2021. The chemical and lipid composition of the inflorescences during the vegetation process of the plant were established. A significant decrease in total proteins (from 8.7 to 7.4%), glyceride oils (2.0-1.7%), and ash (4.5-4.2%) content was observed, while the amount of carbohydrates (72.3-77.2%) and fibers (28.7-35.8%) increased. During the vegetation of the plant, the content of oleic and linoleic acids increased up to 2-3 times, while the level of palmitic acid decreased. The lipids from the seeds were rich in oleic (53.0%) and palmitic (36.2%) acids. The tocopherol content in the oils of the inflorescences during vegetation increased from 58 to 110 mg/kg, and the content in the oil from the seeds was 260 mg/kg. The phospholipid content decreased during vegetation, and differences were observed in the composition between the inflorescences and the seeds. The high content of oleic acid, linoleic acid, tocopherols, and phospholipids determine the nutritional and biological value of the oils isolated from Centaurea thracica, and contribute to their potential use in various directions.

Study on the metabolism of natural sesquiterpene lactones in human liver microsomes using LC-Q-TOF-MS/MS

Sesquiterpene lactones are naturally occurring, highly active -specialised metabolites, which are biosynthesized by important medicinal plants, fulfilling many functions. The in vitro metabolism of parthenolide (1), grosheimin (2), carbetolide C (3), 8α-O-(3,4-dihydroxy--methylenebutanoyloxy)-dehydromelitensin (4) and arteludovicinolide A (5) was examined using human liver microsomes. Phase I, phase II (glucuronidation), as well as combined phase I + II metabolism were studied. Metabolites were identified via liquid chromatography-high resolution quadrupole time-of-flight mass spectrometry. Monohydroxylated, hydrated, carboxylated, methylated derivatives, together with corresponding monoglucuronides were detected, suggesting that the metabolism of sesquiterpene lactones is changeable due to structural features and scaffold diversity, though the lactone ring is the main site of metabolism.

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).

Sesquiterpene lactones as emerging biomolecules to cease cancer by targeting apoptosis

Apoptosis is a programmed cell death comprising two signaling cascades including the intrinsic and extrinsic pathways. This process has been shown to be involved in the therapy response of different cancer types, making it an effective target for treating cancer. Cancer has been considered a challenging issue in global health. Cancer cells possess six biological characteristics during their developmental process known as cancer hallmarks. Hallmarks of cancer include continuous growth signals, unlimited proliferation, resistance to proliferation inhibitors, apoptosis escaping, active angiogenesis, and metastasis. Sesquiterpene lactones are one of the large and diverse groups of planet-derived phytochemicals that can be used as sources for a variety of drugs. Some sesquiterpene lactones possess many biological activities such as anti-inflammatory, anti-viral, anti-microbial, anti-malarial, anticancer, anti-diabetic, and analgesic. This review article briefly overviews the intrinsic and extrinsic pathways of apoptosis and the interactions between the modulators of both pathways. Also, the present review summarizes the potential effects of sesquiterpene lactones on different modulators of the intrinsic and extrinsic pathways of apoptosis in a variety of cancer cell lines and animal models. The main purpose of the present review is to give a clear picture of the current knowledge about the pro-apoptotic effects of sesquiterpene lactones on various cancers to provide future direction in cancer therapeutics.

Anthemis tricolor Containing Unusual Totarol with Cytotoxic and Acetylcholinesterase-Inhibitory Activity

Anthemis tricolor is an endemic species of Cyprus, and there is very limited information on its chemistry and pharmacological activities. The study aims to identify the in-vitro cytotoxic and acetylcholinesterase activities of Anthemis tricolor. The compounds responsible for the activities were also identified. Potent extracts of A. tricolor were subjected to preparative isolation and spectral structure determination studies. The chloroform extract contained many components, and due to the small quantity of extract available, enough pure compound(s) cannot be obtained for structure determination studies, though the n-hexane extract afforded two known compounds, totarol (1) and taraxasterol (2). The structures of the compounds (1 and 2) were determined by 1 H and 13 C NMR experiments. The pure compounds were also tested for their acetylcholinesterase inhibitory properties. For compound 1, the IC50 value was found to be 87.88 μg/mL. However, no inhibition was seen for 2. Anthemis tricolor was established to be a valuable source of pharmacologically active compounds and requires further studies.

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 β-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.

Sesquiterpene Lactones Isolated from Centaurea cineraria L. subsp. cineraria Inhibit the Radicle Growth of Broomrape Weeds

The plant Centaurea cineraria L. subsp. cineraria has been investigated as a potential source of inhibitors of broomrape radicle growth. The latter are weeds that pose a threat to agriculture and for which there are few methods available for the control of infestations. Four sesquiterpene lactones have been isolated from C. cineraria L. subsp. cineraria aerial parts and identified as isocnicin, cnicin, salonitenolide, and 11β,13-dihydrosalonitenolide using spectroscopic, spectrometric, and optical methods. Salonitenolide and 11β,13-dihydrosalonitenolide have been isolated for the first time from this plant. Tested at 1.0-0.1 mM against the broomrape species Phelipanche ramosa, Orobanche minor, Orobanche crenata, and Orobanche cumana, isocnicin, cnicin, and salonitenolide demonstrated remarkable inhibitory activity (over 80% in most of the cases) at the highest concentrations. Structure-activity relationship conclusions indicated the significance of the α,β-unsaturated lactone ring. In addition, the synthetic acetylated derivative of salonitenolide showed the strongest activity among all compounds tested, with inhibitions close to 100% at different concentrations, which has been related to a different lipophilicity and the absence of H-bond donor atoms in its structure. Neither the extracts nor the compounds exhibited the stimulating activity of broomrape germination (induction of suicidal germination). These findings highlight the potential of C. cineraria to produce bioactive compounds for managing parasitic weeds and prompt further studies on its sesquiterpene lactones as tools in developing natural product-based herbicides.

Evaluation of Fatty Acid Contents and Biological Activities of Jurinea turcica

The fatty acid profile, antioxidant/antibacterial, and cytotoxic effects of the extracts obtained from Jurinea turcica B.Doğan& A.Duran have been evaluated for the first time in the current study. The fatty acid profile of ethanolic extracts was determined using the Soxhlet extractor by a gas chromatography-mass spectrometer. The antioxidant and antibacterial activities were measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and ferrous reduction tests and the disc diffusion technique. Additionally, the cytotoxicity and wound healing assays were performed on A549 cells. The highest amount of component in the leaf extract was docosanoic acid methyl ester, whereas abundant arachidonic acid methyl ester was mainly found in the flower extract. The IC50 values, the 50 % scavenging value for the DPPH radical, were 179.13 and 124.67 μg/mL for the leaf and flower extracts, respectively. IC50 values (the half-maximal inhibitory concentration) were 10.4 and 24.7 μg/mL for the flower and leaf extracts, respectively. The leaf extract showed more potent antibacterial activity on Enterococcus faecalis (17 mm) and Staphylococcus aureus (16 mm) bacteria than the flower extract. In conclusion, the extracts of J. turcica have anti-cancerogenic and antibacterial effects. Leaf extracts have antibacterial and anti-metastatic effects, while flower extracts show antioxidant, cytotoxic, and apoptotic properties in A549 cells.

Characterization of Health Beneficial Components in Discarded Leaves of Three Escarole (Cichorium endivia L.) Cultivar and Study of Their Antioxidant and Anti-Inflammatory Activities

Plants of genus Cichorium (Asteraceae) can be used as vegetables with higher nutritional value and as medicinal plants. This genus has beneficial properties owing to the presence of a number of specialized metabolites such as alkaloids, sesquiterpene lactones, coumarins, unsaturated fatty acids, flavonoids, saponins, and tannins. Cichorium endivia L., known as escarole, has achieved a common food status due to its nutritionary value, bitter taste, and the presence of healthy components, and is eaten cooked or raw in salads. Presently, wastes derived from the horticultural crops supply chain are generated in very large amounts. Vegetable waste comprises the discarded leaves of food sources produced during collection, handling, transportation, and processing. The external leaves of Cichorium endivia L. are a horticultural crop that is discarded. In this work, the phytochemical profile, antioxidant, and anti-inflammatory activities of hydroalcoholic extract obtained from discarded leaves of three cultivars of escarole (C. endivia var. crispum 'Capriccio', C. endivia var. latifolium 'Performance' and 'Leonida') typical horticultural crop of the Campania region were investigated. In order to describe a metabolite profile of C. endivia cultivars, the extracts were analysed by HR/ESI/Qexactive/MS/MS and NMR. The careful analysis of the accurate masses, the ESI/MS spectra, and the ¹H NMR chemical shifts allowed for the identification of small molecules belonging to phenolic, flavonoid, sesquiterpene, amino acids, and unsaturated fatty acid classes. In addition, the antioxidant potential of the extracts was evaluated using cell-free and cell-based assays, as well as their cytotoxic and anti-inflammatory activity. All the extracts showed similar radical-scavenging ability while significant differences between the three investigated cultivars emerged in the cell-based assays. The obtained data were ascribed to the content of polyphenols and sesquiterpenes in the extracts. Accordingly, C. endivia by-products can be deemed an interesting material for healthy product formulations.

Antimicrobial activity in Asterceae: The selected genera characterization and against multidrug resistance bacteria

Plants from the Asteraceae family are widely used as ethno medicines to treatment parasitic, malaria, hematemesis, pruritus, pyretic, anthelmintic, wound healing. The aim of this review is to provide an overview of Asteraceae plants antimicrobial activity. The most relevant results from the published studies are summarized and discussed. The species in genus of Artemisia, Echinacea, Centaurea, Baccharis, and Calendula showed antimicrobial activity. Most of these species are usually used as ethno medicines to treat infection, inflammation, and parasitics. The effective part or component for antimicrobial was essential oil and crude extract, and essential oil attracted more attention. It was also reported that nanoparticles coated with crude extract were effective against multidrug resistant bacteria. For multidrug resistant bacteria study, the species in Armtemisia were the most investigated, and Staphylococcus aureus and Escherichia coli were the most studied multidrug resistant strains. The antimicrobial activity was evaluated mainly based on the results of minimum inhibitory concentration (MIC). Few reports have been reported on minimum bactericide concentration (MBC) and its antibacterial mechanisms. According to the reported study results, some plants in Asteraceae have the potential to be developed as bacteriostatic agents and against multidrug resistant bacteria. However, most studies are still in vitro, further clinical and applied studies are needed.

Differential Metabolomic Fingerprinting of the Crude Extracts of Three Asteraceae Species with Assessment of Their In Vitro Antioxidant and Enzyme-Inhibitory Activities Supported by In Silico Investigations

The Asteraceae is a large family, rich in ornamental, economical, and medicinally valuable plants. The current study involves the analytical and pharmacological assessment of the methanolic extracts of three less investigated Asteraceae plants, namely Echinops ritro, Centaurea deflexa, and Tripleurospermum decipiens, obtained by three different extraction methodologies viz. maceration (MAC), ultrasound-assisted extraction (UAE), and homogenizer-assisted extraction (HAE). LC-MS-MS analysis of E. ritro, C. deflexa, and T. decipiens extracts led to the identification of ca. 29, 20, and 33 metabolites, respectively, belonging to flavonoids, phenolic acids, and fatty acids/amides. Although there were significant differences in the quantitative metabolite profiles in the extracts of E. ritro and T. decipiens based on the used extraction method, no significant variation was observed in the extracts of C. deflexa in the three implemented extraction techniques. The antioxidant activities of the nine extracts were assessed in vitro using six different assays viz. DPPH, ABTS, CUPRAC, FRAP, PDA, and metal chelation assay (MCA). The HAE/UAE extracts of E. ritro and the UAE/ MAC extracts of C. deflexa displayed the highest antioxidant activity in the DPPH assay, while the UAE extract of T. decipiens showed the strongest antioxidant activity in both the CUPRAC and MCA assays. The enzyme inhibitory activities of the nine extracts were studied in vitro on five different enzymes viz. tyrosinase, α-amylase, α-glucosidase, acetylcholinesterase (AChE), and butyrylcholinestrase (BChE), affecting various pathological diseases. Concerning C. deflexa, its MAC /UAE extracts showed the strongest inhibition on α-amylase, while its UAE/HAE extracts displayed strong inhibitory power on AChE. However, no significant difference was observed on their effects on tyrosinase or BChE. For T. decipiens, its UAE/HAE showed potent inhibition to α-glucosidase, MAC/ HAE significantly inhibited AChE and BChE, while UAE could strongly inhibit tyrosinase enzyme. For E. ritro, all extracts equally inhibited α-amylase and α-glucosidase, MAC/HAE strongly affected tyrosinase, HAE/MAC best inhibited BChE, while HAE inhibited AChE to a greater extent. Chemometric analysis using PCA plot was able to discriminate between the plant samples and between the implemented extraction modes. The in vitro enzyme inhibitory activities of the extracts were supported by in silico data, where metabolites, such as the lignan arctiin and the flavonoid vicenin-2, dominating the extract of C. deflexa, displayed strong binding to AChE. Similarly, chlorogenic and dicaffeoyl quinic acids, which are some of the major metabolites in the extracts of E. ritro and T. decipiens, bound with high affinity to α-glucosidase.

Guaiane-rich phytochemical profile of Centaurea kotschyi subsp. persica (Boiss.) Wagenitz and identification of hypoglycaemic metabolites

Phytochemical investigation of the aerial parts obtained from the Turkish plant Centaurea kotschyi subsp. persica led to the isolation of nine sesquiterpene lactones belonging to the guaiane class, including the undescribed kotschyols A and B, a monoterpene lactone (daphnauranin E), four known lignans (matairesinol, matairesinoside, arctiin and arctigenin) and an undescribed dihydrobenzofuran neolignan (4-O-glucosylcrataegifin A). The structures of these compounds were defined by spectroscopic analysis, including ECD and 1D/2D NMR, and chemical conversion. Spurred from the traditional use of C. kotschyi subsp. persica and previous reports on the activity of its extracts, the isolated compounds were evaluated for their hypoglycaemic activity disclosing the bioactive components.

A Phytochemical Analysis, Microbial Evaluation and Molecular Interaction of Major Compounds of Centaurea bruguieriana Using HPLC-Spectrophotometric Analysis and Molecular Docking

Centaurea is one of the most important genera within the family Asteraceae. An investigation of the phytochemical composition of Centaurea bruguieriana using Gas-Chromatography coupled to Mass spectrometry (GC-MS) was performed. Antimicrobial activity was evaluated using the minimum inhibitory concentration method (MIC) and validated by molecular docking for the major compounds of the most active fraction (1,10-di-epi-cubenol and methyl 8-oxooctanoate) of C. bruguieriana against three bacterial receptors (TyrRS, DNA gyrase, and dihydrofolate reductase (DHFR)). Evaluation of antioxidant activity was conducted using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. High-performance liquid chromatography (HPLC) was used to identify and quantify the contents of major compounds from ethyl acetate fraction (luteolin 7-O-glucoside, chlorogenic acid, kaempferol and isorhamnetin). The antimicrobial activity test showed that the chloroform fraction was more active against all microbial strains. The results of the molecular docking of two major compounds from chloroform fraction showed that good affinities were made between 1,10-di-epi-cubenol and the three selected receptors (TyrRs: −6.0 Kcal/mol against −8.2 Kcal/mol obtained with clorobiocin (standard); DNA gyrase: −6.6 Kcal/mol against −9.1 Kcal/mole obtained with clorobiocin; DHFR: −7.4 Kcal/mol against −6.3 Kcal/mol obtained with SCHEMBL2181345 Standard). Antioxidant evaluation showed that the ethyl acetate fraction was the most active fraction in DPPH (IC50 49.4 µg/mL) and ABTS (IC50 52.8 µg/mL) models. HPLC results showed the contents of luteolin 7-O-glucoside (7.4 µg/mg), and chlorogenic acid (3.2 µg/mg). Our study demonstrated that C. bruguierana is a promising source of bioactive compounds.

HPLC-DAD phenolics screening and in vitro investigation of haemostatic, antidiabetic, antioxidant and photoprotective properties of Centaurea tougourensis Boiss. & Reut

Introduction

Traditional medicine has an important place in human history and this since antiquity. Indeed, during Egyptian and Chinese civilization era, many detailed manuscripts, describing the therapeutic effect of plants, were found which suggest that folk medicine is the basis of the actual medicine.

Objective

To investigate the phytochemical and pharmacological properties of the n-butanol (n-BuOH) and ethyl acetate (EA) extracts of the aerial part of Centaurea tougourensis.

Methods

The phytochemical evaluation was done based on HPLC-DAD approach. The antioxidant activity was determined by DPPH and cupric ion reducing antioxidant capacity (CUPRAC), while the hemostatic effect was performed using plasma recalcification time (PRT) method. The antidiabetic capacity was investigated by alpha-amylase inhibition assay and the photoprotective test was evaluated by the measurement of sun protection factor (SPF).

Results

13 phenolic compounds were identified in both extracts of C. tougourensis. These extracts showed antioxidant, haemostatic, antidiabetic and photoprotective properties with a dose-dependent manner. Amounts of n-BuOH activities were found higher, with a respective IC50 value of 0.72±0.07 μg/ml in DPPH assay, an A0.50 value lower than 3.125 μg/ml in CUPRAC assay besides a shortening rate percentage of coagulation (86.71%) in haemostatic assay, a moderate inhibition effect on alpha amylase activity with an IC50 value of (711.5±0.03 μg/ml) and a maximum sun protection factor of (56.035). These results were mostly found highly significant (p<0.001) when compared to respective standards.

Conclusion

This study demonstrated some pharmacological effects of C. tougourensis which suggests that our plant could be a good candidate to treat some illnesses related to oxidative stress, bleeding or skin cancer.

Cajamolides A-N: Cytotoxic and anti-inflammatory sesquiterpene lactones from Calea jamaicensis

In the search for bioactive compounds from natural sources against cancer and inflammation, Calea jamaicensis (L.) L., a plant endemic to Panama, was investigated. Using multiple chromatographic steps, seventeen sesquiterpene lactones together with nine chromene derivatives were isolated from the non-polar extract of the plant. Among them, fourteen sesquiterpene lactones and three chromanes are described herein for the first time. Structure elucidation was achieved by extensive spectroscopic analysis and comparison with reported data. The isolated sesquiterpene lactones were tested against HeLa, SK-MEL-28 and HePG2 cancerous cell lines for their cytotoxic effects, as well as in the ICAM-1 assay for their anti-inflammatory potential. This study revealed strong cytotoxic agents on the one hand and strong inhibitors on the other. The compounds inhibited the TNF-α induced ICAM-1 expression on the endothelial HMEC-1 cells in a dose-dependent manner and with no toxicity observed on this non-cancerous cell line. In addition to the well-known cytotoxic activities of sesquiterpene lactones, further exploration may offer a novel therapeutic approach to cope with inflammatory diseases and the genus Calea may serve as a biobank for the isolation of potential phytopharmaceuticals, which could be utilized as leads in drug discovery and therapy.

In vitro cytotoxic and anti-inflammatory activities of sesquiterpene lactones from Centaurea papposa (Coss.) Greuter

In the pursuit of highly active specialized metabolites from endemic plants, Centaurea papposa (Coss.) Greuter, an endemic plant in Algeria and Tunisia, was investigated and afforded eleven sesquiterpene lactones (1-11). Cytotoxic evaluation of these compounds using the in vitro MTT assay on three human cancerous cell lines (HeLa, SK-MEL-28 and HepG2), revealed that isolates 4, 8 and 9 (IC₅₀ ≤ 10 μM) could be potential anti-cancer drugs for cervical cancer according to the National Cancer Institute. Further evaluation of the in vitro anti-inflammatory activity showed that compounds 1 and 4 inhibited the TNF-α induced ICAM-1 expression in HMEC-1 endothelial cells at a maximum of 21% and 2% of the control (IC₅₀ values 21.9 and 5.7 μM, respectively). The Michael reactions of the α-methylene-γ-lactone ring seem to be responsible for the strong activity, while no toxicity was observed in the HMEC-1 cells in all the range of tested concentrations (6.25-50.0 µM).

Identification and characterization of SlbHLH, SlDof and SlWRKY transcription factors interacting with SlDPD gene involved in costunolide biosynthesis in Saussurea lappa

The genes involved in costunolide biosynthesis in Saussurea lappa have been identified recently by our lab. However, the study of transcriptional regulators of these genes was lacking for better opportunities for engineering the pharmacologically important biosynthetic pathway. Therefore, we cloned the promoter region of diphosphomevalonate decarboxylase gene (DPD) and analyzed its cis-acting regulatory elements to reveal the potential transcription factor (TF) binding sites for Dof, bHLH and WRKY family proteins in the gene promoter. The transcriptome study approach followed by the hidden Markov model based search, digital gene expression, co-expression network analysis, conserved domain properties and evolutionary analyses were carried out to screen out seven putative TFs for the DPD-TF interaction studies. Yeast one-hybrid assays were performed and three TFs were reported, namely, SlDOF2, SlbHLH3 and SlWRKY2 from Dof, bHLH and WRKY families, respectively that interacted positively with the DPD gene of the costunolide biosynthetic pathway. The tissue specific relative gene expression studies also supported the linked co-expression of the gene and its interacting TFs The present report will improve the understanding of transcriptional regulation pattern of costunolide biosynthetic pathway.

Sokovic M, Barros L, Ferreira ICFR. Chemical Composition and Plant Growth of Centaurea raphanina subsp. mixta Plants Cultivated under Saline Conditions

The aim of this report was to study the effect of salinity (control: 2dS/m, S1: 4 dS/m and S2: 6 dS/m) and harvest time (first harvest on 9 May 2018 and second harvest on 19 April 2018) on the growth and the chemical composition of Centaurea raphanina subsp. mixta plants. The plants of the first harvest were used for the plant growth measurements (fresh weight and moisture content of leaves, rosette diameter, number and thickness of leaves), whereas those of the second harvest were not used for these measurements due to the flowering initiation, which made the leaves unmarketable due to their hard texture. The results of our study showed that C. raphanina subsp. mixta plants can be cultivated under mild salinity (S1 treatment) conditions without severe effects on plant growth and yield, since a more severe loss (27.5%) was observed for the S2 treatment. In addition, harvest time proved to be a cost-effective cultivation practice that allows to regulate the quality of the final product, either in edible form (first harvest) or for nutraceutical and pharmaceutical purposes as well as antimicrobial agents in food products. Therefore, the combination of these two agronomic factors showed interesting results in terms of the quality of the final product. In particular, high salinity (S2 treatment) improved the nutritional value by increasing the fat, proteins and carbohydrates contents in the first harvest, as well as the tocopherols and sugars contents (S1 and S2 treatments, respectively) in the second harvest. In addition, salinity and harvest time affected the oxalic acid content which was the lowest for the S2 treatment at the second harvest. Similarly, the richest fatty acid (α-linolenic acid) increased with increasing salinity at the first harvest. Salinity and harvest time also affected the antimicrobial properties, especially against Staphylococcus aureus, Bacillus cereus and Trichoderma viride, where the extracts from the S1 and S2 treatments showed high effectiveness. In contrast, the highest amounts of flavanones (pinocembrin derivatives) were detected in the control treatment (second harvest), which was also reflected to the highest antioxidant activity (TBARS) for the same treatment. In conclusion, C. raphanina subsp. mixta plants seem to be tolerant to medium salinity stress (S1 treatment) since plant growth was not severely impaired, while salinity and harvesting time affected the nutritional value (fat, proteins, and carbohydrates) and the chemical composition (tocopherols, sugars, oxalic acid, fatty acids), as well as the bioactive properties (cytotoxicity and antimicrobial properties) of the final product.

Applications of Sesquiterpene Lactones: A Review of Some Potential Success Cases

Sesquiterpene lactones, a vast range of terpenoids isolated from Asteraceae species, exhibit a broad spectrum of biological effects and several of them are already commercially available, such as artemisinin. Here the most recent and impactful results of in vivo, preclinical and clinical studies involving a selection of ten sesquiterpene lactones (alantolactone, arglabin, costunolide, cynaropicrin, helenalin, inuviscolide, lactucin, parthenolide, thapsigargin and tomentosin) are presented and discussed, along with some of their derivatives. In the authors’ opinion, these compounds have been neglected compared to others, although they could be of great use in developing important new pharmaceutical products. The selected sesquiterpenes show promising anticancer and anti-inflammatory effects, acting on various targets. Moreover, they exhibit antifungal, anxiolytic, analgesic, and antitrypanosomal activities. Several studies discussed here clearly show the potential that some of them have in combination therapy, as sensitizing agents to facilitate and enhance the action of drugs in clinical use. The derivatives show greater pharmacological value since they have better pharmacokinetics, stability, potency, and/or selectivity. All these natural terpenoids and their derivatives exhibit properties that invite further research by the scientific community.

Wild and Cultivated Centaurea raphanina subsp. mixta: A Valuable Source of Bioactive Compounds

Centaurea raphanina subsp. mixta (DC.) Runemark is a wild edible species endemic to Greece. This study evaluated the chemical composition and bioactive properties of wild and cultivated C. raphanina subsp. mixta plants. Wild plants had higher nutritional value than cultivated ones, whereas cultivated plants contained more tocopherols. Glucose and sucrose were higher in cultivated plants and trehalose in wild ones. Oxalic and total organic acids were detected in higher amounts in cultivated samples. The main fatty acids were α-linolenic, linoleic and palmitic acid, while wild plants were richer in polyunsaturated fatty acids. Two pinocembrin derivatives were the main phenolic compounds being detected in higher amounts in wild plants. Regarding the antioxidant activity, wild and cultivated plants were more effective in the oxidative haemolysis (OxHLIA) and thiobarbituric acid reactive substances (TBARS) assays, respectively. Moreover, both extracts showed moderate cytotoxicity in non-tumor cell lines (PLP2), while cultivated plants were more effective against cervical carcinoma (HeLa), breast carcinoma (MCF-7) and non-small lung cancer (NCI-H460) cell lines. Finally, wild plants showed higher antimicrobial activity than cultivated plants against specific pathogens. In conclusion, the cultivation of C.raphanina subsp. mixta showed promising results in terms of tocopherols content and antiproliferative effects, however further research is needed to decrease oxalic acid content.

Terpene core in selected aromatic and edible plants: Natural health improving agents

Aromatic plants synthesize and produce aromatic molecules, among these compounds some of them belong to terpenes and terpenoids. Plant species have specific genes involved in secondary metabolism which allows them to synthesize various compounds with terpene core. These kinds of plant species are also known as herbal drugs and they are primarily used as components in medicinal products or simply as health foods. This chapter will focus on terpene and terpenoid compounds found in selected edible and aromatic plants belonging to several plant families. Selected plant species are briefly discussed. Biologically active compounds with terpene core are most frequently found in essential oils of the edible and aromatic species, as well as they are separately isolated and identified from the extracts. Health beneficial effects coming from terpene compounds found in edible and aromatic plants are further presented and include antimicrobial, antiviral, cytotoxic, anticancer, anti-inflammatory and many other pharmacological activities.

The new paradigm for androgenetic alopecia and plant-based folk remedies: 5α-reductase inhibition, reversal of secondary microinflammation and improving insulin resistance

ETHNOPHARMACOLOGICAL RELEVANCE

Research in the past half a century has gradually sketched the biological mechanism leading to androgenetic alopecia (AGA). Until recently the aetiological paradigm has been too limited to enable intelligent commentary on the use of folk remedies to treat or reduce the expression of this condition. However, our understanding is now at a point where we can describe how some folk remedies work, predict how effective they will be or why they fail.

RESULTS

The new paradigm of AGA is that inheritance and androgens (dihydrotestosterone) are the primary contributors and a secondary pathology, microinflammation, reinforces the process at more advanced stages of follicular miniaturisation. The main protagonist to microinflammation is believed to be microbial or Demodex over-colonisation of the infundibulum of the pilosebaceous unit, which can be ameliorated by antimicrobial/acaricidal or anti-inflammatory therapies that are used as adjuvants to androgen dependent treatments (either synthetic or natural). Furthermore, studies reveal that suboptimal androgen metabolism occurs in both AGA and insulin resistance (low SHBG or high DHT), suggesting comorbidity. Both can be ameliorated by dietary phytochemicals, such as specific classes of phenols (isoflavones, phenolic methoxy abietanes, hydroxylated anthraquinones) or polycyclic triterpenes (sterols, lupanes), by dual inhibition of key enzymes in AGA (5α-reductase) and insulin resistance (ie., DPP-4 or PTP1B) or agonism of nuclear receptors (PPARγ). Evidence strongly indicates that some plant-based folk remedies can ameliorate both primary and secondary aetiological factors in AGA and improve insulin resistance, or act merely as successful adjuvants to mainstream androgen dependent therapies.

CONCLUSION

Thus, if AGA is viewed as an outcome of primary and secondary factors, then it is better that a 'multimodal' or 'umbrella' approach, to achieve cessation and/or reversal, is put into practice, using complementation of chemical species (isoflavones, anthraquinones, procyanidins, triterpenes, saponins and hydrogen sulphide prodrugs), thereby targeting multiple 'factors'.