Chemical Composition of Kickxia aegyptiaca Essential Oil and Its Potential Antioxidant and Antimicrobial Activities

The exploration of new bioactive compounds from natural resources as alternatives to synthetic chemicals has recently attracted the attention of scientists and researchers. To our knowledge, the essential oil (EO) of Kickxia aegyptiaca has not yet been explored. Thus, the present study was designed to explore the EO chemical profile of K. aegyptiaca for the first time, as well as evaluate its antioxidant and antibacterial activities, particularly the extracts of this plant that have been reported to possess various biological activities. The EO was extracted from the aerial parts via hydrodistillation and then characterized by gas chromatography-mass spectrometry (GC-MS). The extracted EO was tested for its antioxidant activity via the reduction in the free radicals, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). In addition, the EO was tested as an antibacterial mediator against eight Gram-negative and Gram-positive bacterial isolates. Forty-three compounds were identified in the EO of K. aegyptiaca, with a predominance of terpenoids (75.46%). Oxygenated compounds were the main class, with oxygenated sesquiterpenes attaining 40.42% of the EO total mass, while the oxygenated monoterpenes comprised 29.82%. The major compounds were cuminic aldehyde (21.99%), caryophyllene oxide (17.34%), hexahydrofarnesyl acetone (11.74%), ar-turmerone (8.51%), aromadendrene oxide (3.74%), and humulene epoxide (2.70%). According to the IC₅₀ data, the K. aegyptiaca EO revealed considerable antioxidant activity, with IC₅₀ values of 30.48 mg L^-1 and 35.01 mg L^-1 for DPPH and ABTS, respectively. In addition, the EO of K. aegyptiaca showed more substantial antibacterial activity against Gram-positive bacterial isolates compared to Gram-negative. Based on the minimum inhibitory concentration (MIC), the EO showed the highest activity against Escherichia coli and Bacillus cereus, with an MIC value of 0.031 mg mL^-1. The present study showed, for the first time, that the EO of K. aegyptiaca has more oxygenated compounds with substantial antioxidant and antibacterial activities. This activity could be attributed to the effect of the main compounds, either singular or synergistic. Thus, further studies are recommended to characterize the major compounds, either alone or in combination as antioxidants or antimicrobial agents, and evaluate their biosafety.

Isolation and Biological Properties of the Natural Flavonoids Pectolinarin and Pectolinarigenin-A Review

Flavonoids are metabolites widely distributed in plants and commonly present in foods, such as fruits and vegetables. Pectolinarin, which belongs to the flavone subclass, has attracted considerable attention due to its presence in many medicinal plants. It has turned out to be a good biological agent especially due to its antioxidant, anti-inflammatory, antidiabetic, and antitumor activities, evaluated both in vitro and in vivo. Its aglycone, the metabolite pectolinarigenin, is also known for a series of biological properties including anti-inflammatory and antidiabetic effects. In the first overview on the two metabolites here presented, their collection, isolation and the results of their biological evaluation are reported.

Chemical composition, in vitro antioxidant, anticholinesterase and antibacterial activities of Linaria scariosa Desf

The study was performed on the dichloromethane (DCM), ethyl acetate (EAc) and n-butanol (Bu) fractions (F) obtained from the 80% ethanol extract of Linaria scariosa Desf. aerial parts, collected in the North Eastern region of Algeria. Remarkable total phenolic and flavonoid contents were obtained, mainly for EAcF. These results were in accordance with the antioxidant activity of EAcF against DPPH, ABTS, CUPRAC and reducing power tests. DCMF and BuF exhibited significant cholinesterase activity inhibition of BChE and AChE. Moreover, EAcF displayed only moderate antibacterial activities, especially against S. aureus. The biological results were correlated to the chemical components, deduced by both GC-MS analysis of the fractions and the isolation of hemipholin, pectolinarigenin, antirride, antirrinoside, pectolinarin and linariosise, some of which known to exhibit potent effects on the tested biological activities. The study provides the first biological and chemical investigation on Linaria scariosa Desf (unresolved name).

A syn-ent-labdadiene derivative with a rare spiro-β-lactone function from the male cones of Wollemia nobilis

An undescribed labdane-like diterpene with a rare spiro-β-lactone function was identified from the ethanol extract of the male cones of the coniferous tree Wollemia nobilis. This spirolabdadienolide (IUPAC name: syn-ent-8(17),13-labdadien-19,18-olid-15-oic acid methyl ester; trivial name: wollemolide), was isolated by means of traditional and high performance chromatography techniques and structurally elucidated through NMR and MS. In addition, six further known metabolites were evidenced in the extract. Wollemolide, which may be considered an additional chemotaxonomic marker, and 4'-O-methyl-scutellarein, a simple flavonoid, had not been isolated in our previous phytochemical study on the same plant organ. This demonstrates how the molecular pattern of a plant species is in continuous movement and changes with the passing of time according to the climate of the year.

New iridoid glycosides from Anarrhinum pubescens

Six metabolites (1-6) were isolated from the aerial parts of Anarrhinum pubescens Fresen. (Plantaginaceae) growing in Saint Catherine region in Egypt; two of them (1 and 4) are here reported to be newly identified naturally occurring iridoids. The isolated metabolites were identified as 6-O-foliamenthoyl-(6'-O-cinnamoyl)-antirrhinoside (1), 6'-O-cinnamoyl-antirrhinoside (2), the iridoid dimer, pubescensoside (4), antirrhinoside (5), 10-hydroxy-antirrhinoside (6), and the flavonoid, diosmin (3). Identification of the new metabolites was based on analysis of their collected spectroscopic data (NMR and HR-ESI-MS). Furthermore, compounds (1, 4, and 5) were subjected to cytotoxic testing against the human lung carcinoma cell line (A-549); compound 4 showed better cytotoxic activity as indicated by the obtained (IC₅₀).

Phytochemical profile of Euphorbia peplus L. collected in Central Italy and NMR semi-quantitative analysis of the diterpenoid fraction

In this work, the phytochemical profile of the ethanolic extract of Euphorbia peplus L. collected in Central Italy, was reported. This specimen had never been studied before and the analysis was accomplished by means of Column Chromatography for the separation procedure and by means of NMR Spectroscopy and Mass Spectrometry for the identification step. In particular, fourteen compounds were evidenced belonging to five different classes of natural compounds i.e. triterpenoids (pentacyclic and saponin), peculiar diterpenoids (jatrophanes and pepluanes), flavonoids (flavonols), caffeoyl-quinic acids and rare disaccharides. In addition to this, a semi-quantitative analysis on the diterpenoid fraction, by means of NMR Spectroscopy, was also performed in order to provide the real quantities of these compounds in the same fraction and in the total extract. Due to the pronounced chemo variability observed in Euphorbia spp., the availability of a reliable and quick analytical technique, such as that reported in the present study, could be a useful tool in the standardization of plant materials to be used in pharmacological studies or for ethnomedicinal purposes. The technical details for both the general phytochemical analysis and the specific quantitative one, were inserted in this paper. Moreover, the chemotaxonomic and ethnopharmacological relevance of these compounds was also discussed.

Bioactive Constituents of Juniperus turbinata Guss. from La Maddalena Archipelago

A comprehensive phytochemical study of Juniperus turbinata (Cupressaceae) collected from La Maddalena Archipelago (Sardinia, Italy) is reported. Both the essential oil and the ethanolic extract obtained from the aerial parts were analyzed. The essential oil appears to belong to a new chemotype compared to other Mediterranean juniper accessions, as it was favored by geographic isolation of the isles. It showed a low content of monoterpene hydrocarbons and α-terpineol, ent-manoyl oxide, 1,10-di-epi-cubenol as the major constituents. The ethanolic fraction contained mainly diterpenoids. Among these, 15-formyloxyimbricatolic acid (7) is a new natural product since it has hitherto been obtained only by synthetic route. The phenolic fraction contained biflavonoids: cupressuflavone (9), followed by minor amounts of amentoflavone (10) and hinokiflavone (11). The essential oil and six purified compounds (1 - 4, 8 and 9) were assessed for biological activities, namely antioxidant (assessed by DPPH^· , ABTS^·+ and FRAP methods) and cytotoxic effects towards selected human tumor cell lines (MDA-MB 231, A375 and HCT116 cells). Compound 3 exhibited higher radical scavenging activity against ABTS^·+ radical than the reference Trolox. Noteworthy, compound 8 showed powerful effects towards tumor cell lines, with IC₅₀ values in the range of 0.060 - 0.201 μm, which make it a promising anticancer drug candidate.