Phytochemical characterization and biological activity of secondary metabolites from three Limonium species

The chemical composition of the aerial parts' essential oil of Limonium lobatum (L.f.) Chaz. growing wild in Algeria

The Limonium genus (Plumbaginaceae) includes several species of perennial herbs and shrubs belonging to a particular type of halophytes, known as 'recretohalophytes'. Limonium species are widely distributed in the Mediterranean region, mainly in the North-Eastern and Southern countries and several bioactivities have been well documented. In the present study, the chemical composition of the essential oil (EO) of the aerial parts of Limonium lobatum (L.f.) Chaz., a species never chemically previously studied and collected in Algeria, which grows in South Spain, North Africa, and SW Asia, was analysed using GC-MS. The main constituents of the EO were monoterpenes involving eucalyptol (14.21%), β-pinene (8.62%), β-myrcene (8.18%). Among the sesquiterpene compounds β-caryophyllene (8.94%) was the major one. The chemical profile of the EO presented here was compared with the EOs of previously investigated Limonium taxa. Furthermore, a complete literature review on the ethno-pharmacological uses of Limonium species was performed.

In vitro antiglycation and antioxidant properties of Eugenia pyriformis leaves and fruits

Eight phenolic compounds were isolated from Eugenia pyriformis leaves fraction by semi-preparative HPLC and characterized by Nuclear Magnetic Resonance (NMR) and mass spectrometry (ESI-MS). Five compounds were isolated and identified for the first time in E. pyriformis species, while this is the first report of the accumulation of isoquercitrin, quercitrin, and the aglycone quercetin in its leaves. E. pyriformis leaves and fruits extracts, as well as the compounds isolated from the leaves most active fraction, were evaluated for their antiglycation and antioxidant activities. The mixture of myricetin-3-O-(2″-O-galloyl)-α-L-rhamnoside and myricetin-3-O-(4″-O-galloyl)-α-L-rhamnoside showed the highest antiglycation activity. These results suggest that this species is a promising source of bioactive compounds. Further studies to investigate the inhibition of the glycation process in vivo are necessary to evaluate its use in the treatment and/or prevention of advanced glycation end-products (AGEs)-associated diseases.

Comprehensive identification and quantification of unexploited phenolic compounds from red and yellow araçá (Psidium cattleianum Sabine) by LC-DAD-ESI-MS/MS

LC-DAD-ESI-MS/MS was used to comprehensively characterise the non-extractable phenolic compounds (NEPC) in red and yellow araçá genotypes. Results showed a total of 45 and 43 phenolic compounds in the NEPC fraction and, similarly, 51 and 50 compounds in extractable phenolic compounds (EPC) fraction from red and yellow araçá, respectively. Gallic acid and ellagic acid were the unique compounds found in both fractions. The NEPC fraction represented about 35% (m/m) of the total phenolic content and was characterised by an abundance of phenolic acids, while the EPC fraction was rich in flavanols. Although NEPC represented one-third of the total phenolic compounds found in araçá, its antioxidant capacity (against peroxyl radical) was 50% higher than the EPC fraction. The results of this work show that the NEPC fraction of araçá has great diversity and a relatively high concentration of low-molecular-weight phenolic compounds with high antioxidant capacity.

Antiplasmodial natural products: an update

Background

Malaria remains a significant public health challenge in regions of the world where it is endemic. An unprecedented decline in malaria incidences was recorded during the last decade due to the availability of effective control interventions, such as the deployment of artemisinin-based combination therapy and insecticide-treated nets. However, according to the World Health Organization, malaria is staging a comeback, in part due to the development of drug resistance. Therefore, there is an urgent need to discover new anti-malarial drugs. This article reviews the literature on natural products with antiplasmodial activity that was reported between 2010 and 2017.

Methods

Relevant literature was sourced by searching the major scientific databases, including Web of Science, ScienceDirect, Scopus, SciFinder, Pubmed, and Google Scholar, using appropriate keyword combinations.

Results and Discussion

A total of 1524 compounds from 397 relevant references, assayed against at least one strain of Plasmodium, were reported in the period under review. Out of these, 39% were described as new natural products, and 29% of the compounds had IC₅₀ ≤ 3.0 µM against at least one strain of Plasmodium. Several of these compounds have the potential to be developed into viable anti-malarial drugs. Also, some of these compounds could play a role in malaria eradication by targeting gametocytes. However, the research into natural products with potential for blocking the transmission of malaria is still in its infancy stage and needs to be vigorously pursued.

A New Prenylated Isoflavonoid From Limonium leptophyllum

Phytochemical investigation of methanolic extract of Limonium leptophyllum (Plumbaginaceae), led to the isolation of 1 new isoflavonoid with a rare 5-membered dihydrofuran ring (1, leptoisoflavone A) and 8 known compounds. The known isolated compounds were identified as euchrenone b9 (2), auriculasin (3), kaempferol (4), avicularoside (5), myricetin-3-arabinoside (6), trans-N-feruloyltyramine (7), trans-N-caffeoyltyramine (8), and β-sitosterol (9). The crude methanolic extract exhibited moderate activity toward endocannabinoid receptors. Auriculasin (3) showed activity toward cannabinoid receptor type 1 (86.7% displacement with IC50 8.92 μM).