Prevalence of Diterpenes in Essential Oil of Euphorbia mauritanica L.: Detailed Chemical Profile, Antioxidant, Cytotoxic and Phytotoxic Activities.

Plants belonging to Euphorbia L. genus are considered very interesting from a medicinal point of view due to their diverse metabolites and bioactivities. The essential oil (EO) of Euphorbia mauritanica L. is not studied up to date. Therefore, the present study aimed to explore the chemical profile of this EO and evaluate its antioxidant, cytotoxic, and allelopathic potentialities. The EO was extracted from the whole plant via hydrodistillation and then, analyzed by gas chromatography/mass spectrometry (GC/MS). The correlation of E. mauritanica with the other Euphorbia plants was established using chemometric analysis. The antioxidant activity was determined based on scavenging of the free radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The anti-proliferation of the EO on the Hep G2 and MCF-7 cells was evaluated. Finally the allelopathic activity of the EO was assessed against the two noxious weeds, Dactyloctenium aegyptium and Urospermum picroides. Forty-one compounds were identified using GC/MS analysis, with an abundance of terpenoids (91.54 %) that were categorized into mono- (30.75 %), sesqui- (15.23 %), and diterpenes (45.56 %). Interestingly, the results revealed the preponderance of diterpenoid constituents although they are rarely found in the EOs of the plant kingdom. The major compounds were (3E)-cembrene A (18.66 %), verticiol (17.05 %), limonene (7.91 %), eucalyptol (7.26 %), α-pinene (5.61 %), neo-cembrene A (3.52 %), kaur-16-ene (3.24 %), and cembrene (3.09 %). The EO showed moderate antioxidant activity where it attained IC50 values of 83.34 and 64.21 µg mL-1 for DPPH and ABTS compared to 23.01 and 19.23 µg mL-1 for ascorbic acid as standard, respectively. The EO exhibited very weak cytotoxic effect on MCF-7 and Hep G2 cells. The EO showed significant allelopathic activities against the weeds D. aegyptium and U. picroides in a concentration-dependent manner. EO was found more effective against U. picroides than D. aegyptium with IC50 values of 0.79, 0.45, and 0.67 mg mL-1 and 1.17, 0.55, and 1.08 mg mL-1 for germination, root, and shoot growth, respectively. Due to the high content of diterpenes in E. mauritanica, further study is recommended for more characterization of pure forms of the identified diterpenes as well as evaluating their bioactivity either solely or synergistically.

Volatiles Profiling, Allelopathic Activity, and Antioxidant Potentiality of Xanthium Strumarium Leaves Essential Oil from Egypt: Evidence from Chemometrics Analysis.

The essential oil (EO) of Xanthium strumarium L. leaves (family: Asteraceae) was extracted by hydrodistillation, and then analyzed by gas chromatography-mass spectrometry (GC-MS). Forty-three essential compounds were identified. The sesquiterpenoids represented the major constituents (72.4%), including oxygenated (61.78%) and non-oxygenated (10.62%) sesquiterpenes, followed by monoterpenes (25.19%). The diterpenoids and oxygenated hydrocarbons were determined as minor compounds. The main constituents of the EO were 1,5-dimethyltetralin (14.27%), eudesmol (10.60%), l-borneol (6.59%), ledene alcohol (6.46%), (-)-caryophyllene oxide (5.36%), isolongifolene, 7,8-dehydro-8a-hydroxy (5.06%), L-bornyl acetate (3.77%), and aristolene epoxide (3.58%). A comparative analysis was stated here between the EO of Egyptian X. strumarium and those previously reported from Pakistan, Iran, and Brazil based on chemometic tools such as principal components analysis (PCA) and agglomerative hierarchical clustering (AHC). The EO of X. strumarium showed weak 1, 1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity with IC50 321.93 µL/L-1, which was comparable to ascorbic acid as a reference. However, the EO exhibited significant allelopathic potential regarding the germination and growth of the noxious weed Bidens pilosa in a concentration-dependent manner. Therefore, further study is recommended to characterize the EO from X. strumarium as an eco-friendly green bioherbicide against weeds, as well as determine their mode of actions.

Essential Oil Composition, Antioxidant and Allelopathic Activities of Cleome droserifolia (Forssk.) Delile.

People rely on the synthetic chemical pesticides in most of the agricultural practices, which have a serious problem on human health and ecosystem. Essential oil (EO), derived from wild plants, offers a new opportunity to explore eco-friendly green biocides. This study aimed to characterize the chemical constituents of EO from Egyptian ecospecies of Cleome droserifolia (Forssk.) Delile and evaluate its antioxidant and allelopathic potential. The EO was extracted from aerial parts by hydrodistillation and analyzed by GC/MS. To assess the allelopathic potential, EO concentrations from 50 to 200 µL L-1 were tested on Trifolium repens and three weeds. Antioxidant activity was determined using DPPH. Hydrodistillation yielded 0.64 % of dark yellow oil, which comprises 35 compounds, in which sesquiterpene was a major class and represented by 61.97 % of the total essential oil. Moreover, the dominant sesquiterpenes are cis-nerolidol, α-cadinol, δ-cadinene, and γ-muurolene. The speed of germination index, shoot and root length of clover and weeds were reduced in a concentration-dependent manner. The IC50 values of C. droserifolia EO on germination of T. repens, Cuscuta trifolii, Melilotus indicus, and Chenopodium murale were 181.6, 183.5, 159.0, and 157.5 µL L-1 , respectively. From the obtained data, we concluded that C. droserifolia EO could provide a hope to produce environment-friendly bioherbicide as well as a natural resource of antioxidants.

Faster N Release, but Not C Loss, From Leaf Litter of Invasives Compared to Native Species in Mediterranean Ecosystems.

Plant invasions can have relevant impacts on biogeochemical cycles, whose extent, in Mediterranean ecosystems, have not yet been systematically assessed comparing litter carbon (C) and nitrogen (N) dynamics between invasive plants and native communities. We carried out a 1-year litterbag experiment in 4 different plant communities (grassland, sand dune, riparian and mixed forests) on 8 invasives and 24 autochthonous plant species, used as control. Plant litter was characterized for mass loss, N release, proximate lignin and litter chemistry by 13C CPMAS NMR. Native and invasive species showed significant differences in litter chemical traits, with invaders generally showing higher N concentration and lower lignin/N ratio. Mass loss data revealed no consistent differences between native and invasive species, although some woody and vine invaders showed exceptionally high decomposition rate. In contrast, N release rate from litter was faster for invasive plants compared to native species. N concentration, lignin content and relative abundance of methoxyl and N-alkyl C region from 13C CPMAS NMR spectra were the parameters that better explained mass loss and N mineralization rates. Our findings demonstrate that during litter decomposition invasive species litter has no different decomposition rates but greater N release rate compared to natives. Accordingly, invasives are expected to affect N cycle in Mediterranean plant communities, possibly promoting a shift of plant assemblages.

Allelopathic Activity and Chemical Composition of Rhynchosia minima (L.) DC. Essential Oil from Egypt.

Aromatic plants attract the attention of many researchers worldwide due to their worthy applications in agriculture, human prosperity, and the environment. Essential oil (EO) could be exploited as effective alternatives to synthetic compounds as it has several biological activities including allelopathy. The EO from the aerial parts of Rhynchosia minima was extracted by hydrodistillation and investigated by gas chromatography/mass spectrometry (GC/MS). Different concentrations (50, 100, 150 and 200 µL L-1 ) of the EO were prepared for investigation of their allelopathic potential on two weeds; Dactyloctenium aegyptium and Rumex dentatus. Twenty-eight compounds, mainly sesquiterpenes (69.13%) were determined. The major compounds are α-eudesmol, 2-allyl-5-tert-butylhydroquinone, caryophyllene oxide, trans-caryophyllene, and τ-cadinol. The EO from the R. minima showed a significant inhibition of D. aegyptium and R. dentatus germination, while the seedling growth was stimulated. Therefore, it is not recommended to treat these noxious weeds with the EO of R. minima before the germination. In contrast, the apparent stimulatory effect on the seedling growth offers further studies to use the EO of R. minima to enhance the fitness of different economic crops. However, characterization of green bio-herbicides such as EO (allelochemicals) from wild plants raises a new opportunity for the incorporation of new technology of bio-control against the noxious weeds.

Comparing chemistry and bioactivity of burned vs. decomposed plant litter: different pathways but same result?

Litter burning and biological decomposition are oxidative processes co-occurring in many terrestrial ecosystems, producing organic matter with different chemical properties and differently affecting plant growth and soil microbial activity. We tested the chemical convergence hypothesis, i.e., materials with different initial chemistry converge toward a common profile, with similar biological effects, as the oxidative process advances, for burning and decomposition. We compared the molecular composition, assessed by 13 C NMR, of seven plant litter types either fresh, decomposed for 30, 90, 180 d in a microcosms incubation experiment, or heated at 100°C, 200°C, 300°C, 400°C, 500°C for 30 minutes. We used litter water extracts (5% dry weight) as treatments in bioassays on plant (Lepidium sativum) and fungal (Aspergillus niger) growth, and a washed quartz sand amended with litter (0.5% dw) to assess heterotrophic respiration by flux chamber (i.e., [µg of CO2 released]·[g added litter]-1 ·d-1 ). We observed different molecular variations for materials either burning (i.e., a sharp increase of aromatic C and a decrease of other fractions above 200°C) or decomposing (i.e., early increase of alkyl, methoxyl, and N-alkyl C and decrease of O-alkyl and di-O-alkyl C fractions). Soil respiration and fungal growth decreased with litter age and heating severity, down to 20% relative to fresh litter. Plants were inhibited on fresh litter (on average 13% of the control), but recovered on aged (180 d) and heated (30 min at 500°C) materials, up to 126% and 63% of the control, respectively. Correlation between the intensity of 13 C NMR signals in litter spectra and bioassay results showed that O-alkyl, methoxyl, and aromatic C fractions are crucial to understand organic matter effects, with plant response negatively affected by labile C but positively associated to lignification and pyrogenic C. The pattern of association of soil respiration and fungal growth to these C fractions was essentially opposite to that observed for plant root growth. Our findings suggest a functional convergence of decomposed and burned organic substrates, emerging from the balance between the bioavailability of labile C sources and the presence of recalcitrant and pyrogenic compounds, oppositely affecting different trophic levels.

Anti-inflammatory, Antipyretic, and Antinociceptive Effects of a Cressa cretica Aqueous Extract.

Cressa cretica is a widely grown halophytic plant traditionally used for the treatment of different ailments. Previous investigations reported its biological activity on a wide spectrum of diseases. In this study, in vivo antinociceptive, anti-inflammatory, and antipyretic activities of C. cretica aqueous extract whole plant were evaluated. In addition, the total polyphenol content, the total flavonoid content, and the chemical characterization of the extract were performed. C. cretica showed writhing inhibition in acetic acid-induced peripheral nociception of 43 and 48 % at doses of 50 and 100 mg/kg, respectively. The same doses increased latency time in a hot plate model of central analgesia by 66 and 78 % compared to the control group, respectively. The acute anti-inflammatory effect of the extract was explored in the carrageenan-induced rat hind paw test. The inhibition of paw volume was better than that of the standard drug indomethacin. C. cretica significantly decreased rectal temperature in the rats injected with Brewer's yeast. C. cretica aqueous extract showed both central and peripheral antinociceptive activities and was effective as an anti-inflammatory and antipyretic. Phenolic compounds, including chlorogenic acids and flavonol glycosides, were identified by HPLC-PDA-ESI-MS techniques. These findings indicate the medicinal importance of this traditionally used plant as a therapeutic remedy for different ailments.

Postsurgical Pyoderma Gangrenosum Versus Necrotizing Fasciitis: Can We Spot the Difference?

BACKGROUND: Pyoderma gangrenosum is a rare noninfectious cutaneous disease characterized by expanding areas of skin ulceration around necrotic centers with purulent debris. Exceptionally, it can be precipitated by surgery alone, and this entity has been described as postsurgical pyoderma gangrenosum (PSPG). Cases of PSPG in the literature are rare. METHODS: We performed a retrospective review of the current literature on PSPG and highlight some observed differences between these conditions. We also present our experience of PSPG imitating an infectious process post reduction mammoplasty. RESULTS: Although PSPG can demonstrate fever, malaise, systemic signs, and serology that mimic the sepsis of necrotizing fasciitis, we identify some features that can aid diagnosis of pyoderma gangrenosum in the absence of pathergy (which is pathognomonic). These include premorbid inflammatory bowel disease, hematological malignancy, or inflammatory polyarthritis; the exquisite and disproportionate pain associated (in particular within surrounding normal skin); symmetrical changes on both breasts; specific histopathological changes with absence of microorganisms; cutaneous wounds demonstrating an ulcerated, violaceous, and undermined edge; and, in this case, bilaterally spared nipple-areola complexes suggesting progression within continuous skin up to but not across incision lines. CONCLUSIONS: We hope that, in encouraging a higher index of suspicion, prompt diagnosis, and accurate treatment, a better outcome for both patient and surgeon can be achieved in future cases.