Sesquiterpenes, flavonoids, shikimic acid derivatives and pyrrolizidine alkaloids from Senecio kingii Hook

Insect Antifeedant Benzofurans from Pericallis Species

In this work, we have studied the benzofurans of Pericallis echinata (aerial parts and transformed roots), P. steetzii (aerial parts and transformed roots), P. lanata (aerial parts), and P. murrayi (aerial parts and roots). This work has permitted the isolation of the new benzofurans 10-ethoxy-11-hydroxy-10,11-dihydroeuparin (10), (-)-eupachinin A ethyl ether (12), 11,15-didehydro-eupachinin A (13), 10,12-dihydroxy-11-angelyloxy-10,11-dihydroeuparin (14), 2,4-dihydroxy-5-formyl-acetophenone (15) isolated for the first time as a natural product, 11-angelyloxy-10,11-dihydroeuparin (16), and 12-angelyloxyeuparone (17), along with several known ones (1-9, 11). In addition, the incubation of the abundant component, 6-hydroxytremetone (1), with the fungus Mucor plumbeus has been studied. Benzofurans in the tremetone series (1, 1a, 2-5, 18, 18a), the euparin series (6, 7, 7a, 8-10, 14, 16), and the eupachinin-type (11, 12) were tested for antifeedant effects against the insect Spodoptera littoralis. The antifeedant compounds (1, 4, 6, 11, 12) were further tested for postingestive effects on S. littoralis larvae. The most antifeedant compounds were among the tremetone series, with 3-ethoxy-hydroxy-tremetone (4) being the strongest antifeedant. Glucosylation of 1 by its biotransformation with Mucor plumbeus gave inactive products. Among the euparin series, the dihydroxyangelate 14 was the most active, followed by euparin (6). The eupachinin-type compounds (11, 12) were both antifeedants. Compounds 4, 11, and 12 showed antifeedant effects without postingestive toxicity to orally dosed S. littoralis larvae. Euparin (6) had postingestive toxicity that was enhanced by the synergist piperonyl butoxide.

Cumulative Data of 1H and 13C NMR Signals and Specific Rotations of Eremophilane Sesquiterpenoids. 1. Bicyclic Eremophilanes (1)

1H and 13C Nuclear Magnetic Resonance (NMR) signals and specific rotations of eremophilane sesquiterpenoids are cumulated as a series of review articles. In the first chapter of this review, 332 bicyclic eremophilanes, namely with no furan or lactone rings (except for epoxides), without 3-OR functionality (except for hydroxy, acetoxy, and carbonyl) are listed in tables. These data may help chemists working in the area of natural products chemistry as well as synthetic scientists.

Histopathological evaluation of Senecio rhizomatus Rusby in 7,12-dimethylbenz(α) anthracene-induced breast cancer in female rats

Background and Aim:

Senecio rhizomatus Rusby (SrR) is a medicinal plant of the Asteraceae family and traditionally consumed as infusion in the Andean region from Peru for inflammatory disorders. This study aimed to determine the histopathological changes afforded by SrR in 7, 12-dimethylbenz[a]anthracene (DMBA)-induced breast cancer (BC) in rats.

Materials and Methods:

An ethanolic extract of SrR aerial parts was prepared by maceration with 96% ethanol, and the chemical components were identified by gas chromatography coupled to mass spectrometry; the antioxidant activity was determined by 1,1-diphenyl-2-picril-hidrazil (DPPH) assay; and the acute toxicity was assessed according to the OCED 423 guidelines. In a pharmacological study, 30 female Holztman rats were distributed randomly into five groups, as follows. Group I: Negative control (physiological serum, 2 mL/kg); Group II. DMBA (80 mg/Kg body weight); and Groups III, IV, and V: DMBA + ethanol extract of SrR at doses of 10, 100, and 200 mg/kg, respectively.

Results:

The antioxidant activity of the SrR extract against DPPH was 92.50% at 200 mg/mL. The oral administration of SrR at doses of 50, 300, 2000, and 5000 mg/kg did not show any clinical evidence of toxicity or occurrence of death. The groups that received SrR presented a lower frequency of tumors and acumulative tumor volume compared with the DMBA group (p<0.05); the DMBA group exhibited a higher incidence of necrosis and moderate mitosis, up to 66.67% and 100.00%, respectively. Finally, infiltrating carcinoma with extensive tumor necrosis was evidenced.

Conclusion:

In experimental conditions, the ethanolic extract of SrR had a protective effect in DMBA-induced BC in female rats. Furthermore, the antioxidant activity of its main phytochemicals could be responsible for the effect observed, and SrR seems to be a safe extract in the preclinical phase.

Inhibitory effects of compounds from the roots of Potentilla longifolia on lipid accumulation

Potentilla longifolia is a kind of Chaoyao medicine, which is a branch of traditional Chinese medicine. The plant is often referred to as ganyancao or ganyearmcao, which means that it has a significant therapeutic effect on liver inflammation. In previous experiments, we found that a water extract of ganyearmcao inhibited lipid accumulation. In the present study, we isolated one new (ganyearmcaoone A, 1) and eight known compounds (2–9) from a water extract of the dried roots of ganyearmcao; all of the compounds were isolated for the first time from this medicinal plant. We elucidated the chemical structures of these compounds using comprehensive analyses of HR-ESI-MS and 1D, 2D NMR. We evaluated the inhibitory effects of the nine compounds on lipid accumulation in 3T3-L1 cells; we did so using photographic and quantitative assessments of the lipid content with oil red O staining and by measuring triglyceride levels. Compared with the control, compounds 6 and 9 significantly inhibited differentiation of 3T3-L1 cells and lipid accumulation. Compound 1 showed potential inhibitory effects on lipid accumulation. Molecular docking results indicated that compounds 6 and 9 may efficiently bind to AMPK and its downstream kinase (SCD1), thereby inhibiting lipid accumulation. Our results demonstrate that ganyearmcao and its components may play an important role in treating diseases related to lipid accumulation in the future.

Insect Antifeedant Components of Senecio fistulosus var. fistulosus-Hualtata

From a bioactive methanolic extract of Senecio fistulosus, the antifeedant effects of the alkaloidal and non-alkaloidal fractions were tested against the insects Spodoptera littoralis, Myzus persicae and Rhopalosiphum padi, with the non-alkaloidal fraction being antifeedant. The phytochemical study of the non-alkaloidal fraction of S. fistulosus, resulted in the isolation of four compounds, two 9-oxo-furanoeremophilanes (1, 2), an eremophilanolide, 1β,10β-epoxy-6-acetoxy-8α-hydroxy-eremofil-7(11)-en-8β,12-olide (3) and a maaliol derivative (4). The alkaloidal fraction yielded two known pyrrolizidine alkaloids (5, 6). Compounds 1, 3 and 4 are new natural products. Furanoeremophilane 2 was a strong antifeedant against S. littoralis and maaliane 4 inhibited the settling of M. persicae.

Label-free quantitative proteomics to investigate the response of strawberry fruit after controlled ozone treatment

To elucidate postharvest senescence in strawberry (Fragaria ananassa Duch. var. 'JingTaoXiang') fruit in response to ozone treatment at different concentrations (0, 2.144, 6.432, and 10.72 mg m-3), a label-free quantitative proteomic investigation was performed. Postharvest physiological quality traits including respiration rate, firmness, titratable acid, and anthocyanin content were characterized. The observed protein expression profile after storage was related to delayed senescence in strawberries. A total of 2413 proteins were identified in differentially treated strawberry fruits, and 382 proteins were differentially expressed between the four treatments on day 7 and the initial value (blank 0). Proteins related to carbohydrate and energy metabolism and anthocyanin biosynthesis, cell stress response, and fruit firmness were characterized and quantified. Ozone treatment at the concentration of 10.72 mg m-3 effectively delayed the senescence of the strawberry. The proteomic profiles were linked to physiological traits of strawberry fruit senescence to provide new insights into possible molecular mechanisms.

Elucidating the mass spectrum of the retronecine alkaloid using DFT calculations

Pyrrolizidine alkaloids are natural molecules playing important roles in different biochemical processes in nature and in humans. In this work, the electron ionization mass spectrum of retronecine, an alkaloid molecule found in plants, was investigated computationally. Its mass spectrum can be characterized by three main fragment ions having the following m/z ratios: 111, 94, and 80. In order to rationalize the mass spectrum, minima and transition state geometries were computed using density functional theory. It was showed that the dissociation process includes an aromatization of the originally five-membered ring of retronecine converted into a six-membered ring compound. A fragmentation pathway mechanism involving dissociation activation barriers that are easily overcome by the initial ionization energy was found. From the computed quantum chemical geometric, atomic charges, and energetic parameters, the abundance of each ion in the mass spectrum of retronecine was discussed.

Structure-Dependent Cytotoxic Effects of Eremophilanolide Sesquiterpenes

The aim of this research was to determine the cytotoxic action of sixteen structurally-related eremophilane-type sesquiterpenes, isolated from several species of Senecio, against a panel of cancer cell lines. The cytotoxic activities were evaluated by WST-1 test and the IC50 values calculated. The investigated compounds exerted dose-dependent cytotoxic actions against selected cancer cell lines and no-tumoral HS5 cell line. The comparative structure-activity relationships demonstrated the importance of C-1, C-6, and C-8 substituents in the molecule. Our results show that eremophilane-type sesquiterpenes may represent an important source of novel potential antitumor agents due to their pronounced cytotoxic actions towards malignant cells.

A plant from the altiplano of Northern Chile Senecio nutans, inhibits the Vibrio cholerae pathogen

BACKGROUND

In the altiplano of Northern Chile the plant Senecio nutans is habitually used as an infusion to relieve the effects of altitude sickness (locally known as "puna"). It is also used to alleviate the bronchitis, whooping cough, asthma, stomachache, tiredness and fever. The extreme conditions under which these plant grow and scientific data that shows the inhibiting potential of the essential oils of plants of the genus Senecio represents great potential in the study of their application to control pathogens like Vibrio Cholera.

METHODS

The essential oil from aerial parts of S. nutans was isolated by hydrodistillation and the chemical composition characterized by GC-MS analyses. The antibacterial potential and determination of MIC value, was estimated in both micro and macro dilution method.

RESULTS

The GC-MS analysis of essential oil of S. nutans showed the presence of methyl cinnamate (44.9 %), p-cymenol (27.2 %), and terpinen-4-ol (6.8 %), α-terpineol (4.1 %), t-cadinol (3.5 %), methyl hydrocinnamate (2.1 %), δ-cadinene (2.0 %), p-cymene (1.9 %), γ-terpinene (1.8 %), α-cadinol (1.6 %), cis-sabinene hydrate (1.1 %), caryophyllene (0.9 %), β-pinene (0.8 %), and α-terpinene (0.6 %) as major components. Moreover, the oil of S. nutans exhibited an important antibacterial activity with a diameter of inhibition zone growth of 22 mm and the MIC value of 0.4 mg/mL against pathogenic bacteria V. cholerae.

CONCLUSIONS

The results show for the first time the antibacterial activity of the essential oils of S. nutans against the V. cholerae pathogen, an activity that can be applied as a preventive treatment against the action of pathogen.