Phytochemical Characterization of Cannabis sativa L. Roots from Northeastern Brazil

This article describes the phytochemical study of Cannabis sativa roots from northeastern Brazil. The dried plant material was pulverized and subjected to exhaustive maceration with ethanol at room temperature, obtaining the crude ethanolic extract (Cs-EEBR). The volatile compounds were analyzed by gas chromatography coupled with mass spectrometry (GC/MS), which allowed to identify 22 compounds by comparing the linear retention index (LRI), the similarity index (SI) and the fragmentation pattern of the constituents with the literature. By this technique the major compounds identified were: friedelan-3-one and β-sitosterol. In addition, two fractions were obtained from Cs-EEBR by classical column chromatography and preparative thin layer chromatography. These fractions were analyzed by NMR and IR and together with the mass spectrometry data allowed to identify the compounds: epifriedelanol, friedelan-3-one, β-sitosterol and stigmasterol. The study contributed to the phytochemical knowledge of Cannabis sativa, specifically the roots, as there are few reports on the chemical constituents of this part of the plant.     

Lichenochemical Screening and Antioxidant Capacity of Four Tunisian Lichen Species

The phenolic composition and antioxidant capacity of four Tunisian lichen species, Cladonia rangiformis, Flavoparmelia caperata, Squamarina cartilaginea and Xanthoria parietina, were determined in order to provide a better understanding of their lichenochemical composition. Powdered material of F. caperata was the richest in total phenolic content (956.68 μg GAE g⁻¹ DW) and S. cartilaginea in proanthocyanidin content (77.31 μg CE g⁻¹ DW), while the acetone extract of X. parietina showed the highest flavonoid content (9.56 μg CE g⁻¹ DW). The antioxidant capacity of all lichen extracts and crude material was evaluated by DPPH^. scavenging, iron-chelating, and iron-reducing powers. Results showed that methanol extracts of S. cartilaginea had the highest DPPH^. antioxidant capacity (IC₅₀=0.9 μg mL⁻¹) and the highest iron-reducing power was attributed to the acetone extract of this species. All extracts of all species were further screened by Fourier-transform infrared spectroscopy (FT-IR) and nuclear resonance spectroscopy (NMR); results showed an abundance of phenols, aromatic compounds, and fatty acids. Overall, our results showed that the investigated species are a rich source of potentially bioactive compounds with valuable properties.     

Reduced impact of ocean acidification on growth and swimming performance of newly hatched tropical sharks (Chiloscyllium plagiosum)

ABSTRACT

Sharks have been facing unprecedented pressure over the last decades, and ocean acidification may represent an additional threat, particularly during their most susceptible life stages. Hence, the present study aimed to investigate the effects of ocean acidification (control pCO₂ ~ 400 μatm; high pCO₂ ~ 900 μatm) on the growth, swimming performance and cholinergic system of juvenile white-spotted bamboo sharks (Chiloscyllium plagiosum). After 45 days of exposure, we observed that high CO₂ did not affect most of the end-points studied. However, somatic growth rate and the percentage of time that sharks spent swimming was significantly reduced under high CO₂ conditions. Moreover, AChE activity decreased in two of the seven brain macroareas analyzed, the telencephalon and optic lobes. As this near-threatened shark species showed small sub-lethal effects to high CO₂ levels, we argue that within a longer time-frame they can potentially reduce individual performance with cascading consequences to shark population dynamics.     

2-styrylchromones as novel inhibitors of xanthine oxidase. A structure-activity study

The purpose of this study was the evaluation of the xanthine oxidase (XO) inhibition produced by some synthetic 2-styrylchromones. Ten polyhydroxylated derivatives with several substitution patterns were synthesised, and these and a positive control, allopurinol, were tested for their effects on XO activity by measuring the formation of uric acid from xanthine. The synthesised 2-styrylchromones inhibited xanthine oxidase in a concentration-dependent and non-competitive manner. Some IC50 values found were as low as 0.55 microM, which, by comparison with the IC50 found for allopurinol (5.43 microM), indicates promising new inhibitors. Those 2-styrylchromones found to be potent XO inhibitors should be further evaluated as potential agents for the treatment of pathologies related to the enzyme's activity, as is the case of gout, ischaemia/reperfusion damage, hypertension, hepatitis and cancer.     

Recovery of tubulin functions after freeze-drying in the presence of trehalose

Microtubules represent cytoplasmic structures that are indispensable for the maintenance of cell morphology and motility generation. Due to their regular structural organization, microtubules have become of great interest for preparation of in vitro nanotransport systems. However, tubulin, the major building protein of microtubules, is a thermolabile protein and is usually stored at −80 °C to preserve its conformation and polymerization properties. Here we describe a novel method for freeze-drying of assembly-competent tubulin in the presence of a nonreducing sugar trehalose. Even after prolonged storage at ambient temperature, rehydrated tubulin is capable of binding antimitotic drugs and assembling to microtubules that bind microtubule-associated proteins in the usual way. Electron microscopy confirmed that rehydrated tubulin assembles into normal microtubules that are able to generate motility by interaction with the motor protein kinesin in a cell-free environment. Freeze-drying also preserved preformed microtubules. Rehydrated tubulin and microtubules can be used for preparation of diverse in vitro and in vivo assays as well as for preparation of bionanodevices.     

2-Styrylchromones: novel strong scavengers of reactive oxygen and nitrogen species

2-Styrylchromones are a small group of naturally occurring chromones, vinylogues of flavones (2-phenylchromones). Natural and synthetic 2-styrylchromones have been tested in different biological systems, showing activities with potential therapeutic applications. In particular, the potential and hitherto understudied antioxidant behavior of these compounds has been raised as a matter of interest. Thus the present work consisted in the study of the in vitro scavenging activities for reactive oxygen species (ROS) and reactive nitrogen species (RNS) of various 2-styrylchromone derivatives and structurally similar flavonoids. Some of the studied 2-styrylchromones proved to be extremely efficient scavengers of the different ROS and RNS, showing, in some cases, IC(50)s under 1 microM. The hydroxylation pattern of 2-styrylchromones, especially in the B-ring but also in the A ring, modulates the activity of these compounds, the catecholic derivatives being the most effective scavengers. The styryl pattern also contributes to their observed outstanding antioxidant activity. In conclusion, the scavenging activities for ROS/RNS of 2-styrylchromone derivatives, here shown for the first time, provide novel and most promising compounds to be applied as antioxidants.     

Potassium-induced alleviation of salinity stress in <Emphasis Type="Italic">Brassica campestris</Emphasis> L.

Salinity is an important abiotic factor that adversely affects major agricultural soils of the world and hence limits crop productivity. An optimum mineral-nutrient status of plants plays critical role in determining plant tolerance to various stresses. A pot experiment was conducted on mustard (Brassica campestris L.) to study the protective role of added potassium (K, 40 mg kg⁻¹ soil) against salinity-stress (0, 40 and 80 mM NaCl)-induced changes in plant growth, photosynthetic traits, ion accumulation, oxidative stress, enzymatic antioxidants and non-enzymatic antioxidants at 30 days after sowing. Increasing NaCl levels decreased the growth, photosynthetic traits and the leaf ascorbate and glutathione content but increased the leaf ion accumulation and oxidative stress, and the activity of antioxidant enzymes. In contrast, K-nutrition improved plant growth, photosynthetic traits, activity of antioxidant enzymes and the ascorbate and glutathione content, and reduced ion accumulation and oxidative stress traits in the leaves, more appreciably at 40 mM than at 80 mM NaCl. The study illustrates the physiological and biochemical basis of K-nutrition-induced NaCl tolerance in mustard as a means to achieving increased crop productivity in a sustainable way.