Optimisation of artemisinin and scopoletin extraction from Artemisia annua with a new modern pressurised cyclic solid-liquid (PCSL) extraction technique.

INTRODUCTION: Artemisia annua is a small herbaceous plant belonging to the Asteraceae family declared therapeutic by the World Health Organisation, in particular for its artemisinin content, an active ingredient at the base of most antimalarial treatments, used every year by over 300 million people. In the last years, owing to low artemisinin content, research of new ways to increase the yield of the plant matrix has led to the use of the total extract taking advantage from the synergic and stabilising effects of the other components. OBJECTIVE: In this work we evaluated and compared the content of artemisinin and scopoletin in extracts of A. annua collected in the Campania Region (southern Italy), by two different extraction processes. METHODOLOGY: Artemisia annua plants were extracted by traditional maceration (TM) in hydroalcoholic solution as a mother tincture prepared according to the European Pharmacopeia and by pressurised cyclic solid-liquid (PCSL) extraction, a new generation method using the Naviglio extractor. RESULTS: The results showed that the PCSL extraction technique is more effective than traditional methods in extracting both phytochemicals, up to 15 times more, reducing the extraction times, without using solvents or having risks for the operators, the environment and the users of the extracts. CONCLUSION: The Naviglio extractor provides extracts with an artemisinin and scopoletin content eight times higher than the daily therapeutic dose, which should be evaluated for its stability over time and biological properties for possible direct use for therapeutic purposes.

Traditional uses, chemical composition and biological activities of Sideritis raeseri Boiss. & Heldr.

Sideritis species have been used in folk medicine for their antimicrobial, antiulcerogenic, digestive and anti-inflammatory properties. Over the years, the phytochemistry of the genus Sideritis has been studied, and various terpenoids, sterols, coumarins and especially flavonoid aglycones and glycosides have been identified. In particular, species from the Balkan Peninsula have been studied and were found to be rich in flavonoids, with valuable antioxidant activity. In the folk medicine of the Balkan countries, Sideritis raeseri is used as a herbal tea in the treatment of inflammation, gastrointestinal disorders and coughs, and also as a tonic, whereas extracts are used as a component of dietary supplements for anaemia. Its dried inflorescences are used to prepare a beverage called 'mountain tea'. In light of the considerable interest generated in the chemistry, pharmacological properties and commercial value of S. raeseri Boiss. & Heldr., we review and summarise the available literature on these plants. The review details the chemical composition of the essential oil, its mineral and polyphenol contents, the naming of these plants and their physicochemical characterisation, and the nuclear magnetic resonance spectral data and biological properties associated with the plant extracts, with a focus on their potential chemotherapeutic applications. © 2016 Society of Chemical Industry.

Polyphenolic Profile and Targeted Bioactivity of Methanolic Extracts from Mediterranean Ethnomedicinal Plants on Human Cancer Cell Lines.

The methanol extracts of the aerial part of four ethnomedicinal plants of Mediterranean region, two non-seed vascular plants, Equisetum hyemale L. and Phyllitis scolopendrium (L.) Newman, and two Spermatophyta, Juniperus communis L. (J. communis) and Cotinus coggygria Scop. (C. coggygria), were screened against four human cells lines (A549, MCF7, TK6 and U937). Only the extracts of J. communis and C. coggygria showed marked cytotoxic effects, affecting both cell morphology and growth. A dose-dependent effect of these two extracts was also observed on the cell cycle distribution. Incubation of all the cell lines in a medium containing J. communis extract determined a remarkable accumulation of cells in the G2/M phase, whereas the C. coggygria extract induced a significant increase in the percentage of G1 cells. The novelty of our findings stands on the observation that the two extracts, consistently, elicited coherent effects on the cell cycle in four cell lines, independently from their phenotype, as two of them have epithelial origin and grow adherent and two are lymphoblastoid and grow in suspension. Even the expression profiles of several proteins regulating cell cycle progression and cell death were affected by both extracts. LC-MS investigation of methanol extract of C. coggygria led to the identification of twelve flavonoids (compounds 1-11, 19) and eight polyphenols derivatives (12-18, 20), while in J. communis extract, eight flavonoids (21-28), a α-ionone glycoside (29) and a lignin (30) were found. Although many of these compounds have interesting individual biological activities, their natural blends seem to exert specific effects on the proliferation of cell lines either growing adherent or in suspension, suggesting potential use in fighting cancer.

Bioactive Compounds of Aristotelia chilensis Stuntz and their Pharmacological Effects.

Aristotelia chilensis ([Molina], Stuntz) a member of the family Eleocarpaceae, is a plant native to Chile that is distributed in tropical and temperate Asia, Australia, the Pacific Area, and South America. The juice of its berries has important medicinal properties, as an astringent, tonic, and antidiarrhoeal. Its many qualities make the maqui berry the undisputed sovereign of the family of so-called "superfruits", as well as a valuable tool to combat cellular inflammation of bones and joints. Recently, it is discovered that the leaves of the maqui berry have important antibacterial and antitumour activities. This review provides a comprehensive overview of the traditional use, phytochemistry, and biological activity of A. chilensis using information collected from scientific journals, books, and electronic searches. Anthocyanins, other flavonoids, alkaloids, cinnamic acid derivatives, benzoic acid derivatives, other bioactive molecules, and mineral elements are summarized. A broad range of activities of plant extracts and fractions are presented, including antioxidant activity, inhibition of visible light-induced damage of photoreceptor cells, inhibition of α-glucosidase, inhibition of pancreatic lipase, anti-diabetic effects, anti-inflammatory effects, analgesic effects, anti-diabetes, effective prevention of atherosclerosis, promotion of hair growth, anti-photo ageing of the skin, and inhibition of lipid peroxidation. Although some ethnobotanical uses have been supported in in vitro experiments, further studies of the individual compounds or chemical classes of compounds responsible for the pharmacological effects and the mechanisms of action are necessary. In addition, the toxicity and the side effects from the use of A. chilensis, as well as clinical trials, require attention.

Gymnema sylvestre R. Br., an Indian medicinal herb: traditional uses, chemical composition, and biological activity.

Gymnema sylvestre R. Br. is one of the most important medicinal plants that grows in tropical forests in India and South East Asia. Its active ingredients and extracts of leaves and roots are used in traditional medicine to treat various ailments and they are present in the market for pharmaceutical and parapharmaceutical products. Commercial products based on substances of plant origin that are generally connoted as natural have to be subjected to monitoring and evaluation by health authorities for their potential impacts on public health. The monitoring and evaluation of these products are critical because the boundary between a therapeutic action and a functional or healthy activity has not yet been defined in a clear and unambiguous way. Therefore, these products are considered borderline products, and they require careful and rigorous studies, in order to use them as complement and/or even replacement of synthetic drugs that are characterized by side effects and high economic costs. This review explores the traditional uses, chemical composition and biological activity of G. sylvestre extracts, providing a general framework on the most interesting extracts and what are the necessary studies for a complete definition of the range of activities.

History of gymnemic acid, a molecule that does not exist. .

In the literature there are hundreds of articles, the first dating back to 1866 and the last to 2014, on gymnemic acid, isolated from Gymnnema sylvestre, from its isolation to the determination of its biological activities. Gymnemic acid has a CAS number but its structure is not specified. Studies during the second half of the 1970s clearly demonstrated that what was being referred to as gymnemic acid is actually a very complex mixture of dozens of substances, belonging to different classes of natural compounds. This plant, whose infusions or complex mixtures of its metabolites are the basis for many formulas sold in pharmacies and by herbalists, has anti-diabetic and slimming effects. It is certainly misleading to talk about gymnemic acid as a specific molecule. There may be doubts about the exact composition of the products, and consequently about their origin and the claimed effects.

Triterpenoids from Gymnema sylvestre and their pharmacological activities.

Because plants are estimated to produce over 200,000 metabolites, research into new natural substances that can be used in the pharmaceutical, agrochemical and agro-industrial production of drugs, biopesticides and food additives has grown in recent years. The global market for plant-derived drugs over the last decade has been estimated to be approximately 30.69 billion USD. A relevant specific example of a plant that is very interesting for its numerous pharmacological properties, which include antidiabetic, anticarcinogenic, and neuroprotective effects is Gymnema sylvestre, used as a medicinal plant in Asia for thousands of years. Its properties are attributed to triterpenoidic saponins. In light of the considerable interest generated in the chemistry and pharmacological properties of G. sylvestre triterpenes and their analogues, we have undertaken this review in an effort to summarise the available literature on these promising bioactive natural products. The review will detail studies on the isolation, chemistry and bioactivity of the triterpenoids, which are presented in the tables. In particular the triterpenoids oxidised at C-23; their isolation, distribution in different parts of the plant, and their NMR spectral data; their names and physico-chemical characterisation; and the biological properties associated with these compounds, with a focus on their potential chemotherapeutic applications.

Synthesis, biophysical characterization and anti-HIV activity of d(TG3AG) Quadruplexes bearing hydrophobic tails at the 5'-end.

Novel conjugated G-quadruplex-forming d(TG3AG) oligonucleotides, linked to hydrophobic groups through phosphodiester bonds at 5'-end, have been synthesized as potential anti-HIV aptamers, via a fully automated, online phosphoramidite-based solid-phase strategy. Conjugated quadruplexes showed pronounced anti-HIV activity with some preference for HIV-1, with inhibitory activity invariably in the low micromolar range. The CD and DSC monitored thermal denaturation studies on the resulting quadruplexes, indicated the insertion of lipophilic residue at the 5'-end, conferring always improved stability to the quadruplex complex (20<ΔTm<40°C). The data suggest no direct functional relationship between the thermal stability and anti-HIV activity of the folded conjugated G-quartets. It would appear that the nature of the residue at 5' end of the d(TG3AG) quadruplexes plays an important role in the thermodynamic stabilization but a minor influence on the anti-HIV activity. Moreover, a detailed CD and DSC analyses indicate a monophasic behaviour for sequences I and V, while for ODNs (II-IV) clearly show that these quadruplex structures deviate from simple two-state melting, supporting the hypothesis that intermediate states along the dissociation pathway may exist.

C-4 gem-dimethylated oleanes of Gymnema sylvestre and their pharmacological activities.

Gymnema sylvestre R. Br., one of the most important medicinal plants of the Asclepiadaceae family, is a herb distributed throughout the World, predominantly in tropical countries. The plant, widely used for the treatment of diabetes and as a diuretic in Indian proprietary medicines, possesses beneficial digestive, anti-inflammatory, hypoglycemic and anti-helmentic effects. Furthermore, it is believed to be useful in the treatment of dyspepsia, constipation, jaundice, hemorrhoids, cardiopathy, asthma, bronchitis and leucoderma. A literature survey revealed that some other notable pharmacological activities of the plant such as anti-obesity, hypolipidemic, antimicrobial, free radical scavenging and anti-inflammatory properties have been proven too. This paper aims to summarize the chemical and pharmacological reports on a large group of C-4 gem-dimethylated pentacyclic triterpenoids from Gymnema sylvestre.

A rapid and simple chromatographic separation of diastereomers of silibinin and their oxidation to produce 2,3-dehydrosilybin enantiomers in an optically pure form.

Silybin A and B were separated from commercial silibinin using the preparative HPLC method. The described method is rapid and effective in obtaining gram-scale amounts of two diastereoisomers with minimal effort. In our approach, silibinin was dissolved in THF (solubility greater than 100 mg/mL), an alternative solvent to H2O or MeOH in which silibinin has a very low solubility (ca 0.05-1.5 mg/mL), and then separated into its two components using preparative RP-HPLC. By starting with purified diastereoisomers, it was possible to obtain the two enantiomers of 2,3-dehydrosilybin in good yields and optically pure using an efficient oxidation procedure. All of the purified products were fully characterised using NMR (¹H, ¹³C), CD, [α](D), and ESI MS analyses. The purities of the products, which were evaluated using analytical HPLC, were greater than 98% in all cases.