Synthesis and Evaluation of Artemisinin-Based Hybrid and Dimer Derivatives as Antimelanoma Agents.

A library of hybrid and dimer compounds based on the natural scaffold of artemisinin was synthesized. These derivatives were obtained by coupling of artemisinin derivatives, artesunate, and dihydroartemisinin with a panel of phytochemical compounds. The novel artemisinin-based hybrids and dimers were evaluated for their anticancer activity on a cervical cancer cell line (HeLa) and on three complementary metastatic melanoma cancer cell lines (SK-MEL3, SK-MEL24, and RPMI-7951). Two hybrid compounds obtained by coupling of artesunate with eugenol and tyrosol, and one of the dimer compounds containing curcumin, emerged as the most active and cancer-selective derivatives.

An olive oil-derived antioxidant mixture ameliorates the age-related decline of skeletal muscle function.

Age-related skeletal muscle decline is characterized by the modification of sarcolemma ion channels important to sustain fiber excitability and to prevent metabolic dysfunction. Also, calcium homeostasis and contractile function are impaired. In the aim to understand whether these modifications are related to oxidative damage and can be reverted by antioxidant treatment, we examined the effects of in vivo treatment with an waste water polyphenolic mixture (LACHI MIX HT) supplied by LACHIFARMA S.r.l. Italy containing hydroxytirosol (HT), gallic acid, and homovanillic acid on the skeletal muscles of 27-month-old rats. After 6-week treatment, we found an improvement of chloride ClC-1 channel conductance, pivotal for membrane electrical stability, and of ATP-dependent potassium channel activity, important in coupling excitability with fiber metabolism. Both of them were analyzed using electrophysiological techniques. The treatment also restored the resting cytosolic calcium concentration, the sarcoplasmic reticulum calcium release, and the mechanical threshold for contraction, an index of excitation-contraction coupling mechanism. Muscle weight and blood creatine kinase levels were preserved in LACHI MIX HT-treated aged rats. The antioxidant activity of LACHI MIX HT was confirmed by the reduction of malondialdehyde levels in the brain of the LACHI MIX HT-treated aged rats. In comparison, the administration of purified HT was less effective on all the parameters studied. Although muscle function was not completely recovered, the present study provides evidence of the beneficial effects of LACHI MIX HT, a natural compound, to ameliorate skeletal muscle functional decline due to aging-associated oxidative stress.

First-time comparison of the in vitro antimalarial activity of Artemisia annua herbal tea and artemisinin.

Artemisia annua tea has been proven to be a very effective treatment for malaria in various clinical trials, but to date its efficacy has not been investigated in vitro. A study was therefore performed to evaluate the effects of A. annua tea on Plasmodium falciparum cultures in vitro. The concentration of artemisinin in the herbal tea preparation was also determined. The herbal tea extract was tested against chloroquine (CQ)-sensitive D10 and CQ-resistant W2 strains of P. falciparum using the parasite lactate dehydrogenase assay. Quantification of artemisinin in the extract of leaves of A. annua was performed using proton nuclear magnetic resonance ((1)H-NMR). Results of the in vitro tests were consistent with the clinical efficacy of A. annua tea [50% inhibitory concentration (IC(50)) for strain D10=1.11±0.21 µg/ml; IC(50) for strain W2=0.88±0.35 µg/ml]. The concentration of artemisinin in A. annua tea (0.18±0.02% of dry weight) was far too low to be responsible for the antimalarial activity. The artemisinin present in the tea is probably co-solubilised with other ingredients, some of which also have antimalarial activity and act synergistically with it. These compounds also merit further research to determine whether their presence hinders the development of parasite resistance compared with pure artemisinin.

Hydroxytyrosol attenuates peripheral neuropathy in streptozotocin-induced diabetes in rats.

Peripheral neuropathy is one of the most frequent and severe complications of diabetes. Hydroxytyrosol (HT), the major antioxidant polyphenolic compound of olive oil, has been investigated as a new potential treatment to counteract the progression of peripheral diabetic neuropathy in rats. An established model of streptozotocin-induced diabetes has been used. After confirmation of hyperglycemia, diabetic and nondiabetic animals were randomized to receive either a low dose or a high dose of HT, or the corresponding vehicle, for 6 weeks. At the end of the 6-week period of treatment, HT blunted plasma thiobarbituric acid-reactive substances increase (p < 0.05) and significantly reduced nerve conduction velocity (p < 0.05) and thermal nociception impairment in diabetic rats (p < 0.05). Sciatic nerve Na(+), K(+)-ATPase activity reduction was also abolished by HT (p < 0.05). The present study provides evidence of the therapeutic potential of the natural substance hydroxytyrosol in the early stage of diabetic neuropathy.

Phytochemical analysis of a herbal tea from Artemisia annua L.

Strategies to control diffusion of malaria needs to account for the increase of resistance of the parasite to the conventional antimalarial drugs. It has been proposed that a traditional aqueous preparation from Artemisia annua, with a low content of the active compound, artemisinin, may reduce the risk of resistance of the protozoa and be relatively more effective in the treatment of the disease. The solubility properties of the molecule have been the matter of concern about the therapeutic usefulness of herbal teas from A. annua. The present study aimed at analysing the chemical profile of a tea infusion from A. annua. Tea from A. annua was prepared through infusion of the plant aerial parts in water for 1, 24 and 48 h. Content of artemisinin was determined by HPLC-ELSD. Overall chemical characterization of the extracts was carried out by a combination of metabolomic techniques. The artemisinin content varied only slightly in the three different extracts (about 0.12%). A series of mono-caffeoyl- and mono-feruloyl-quinic acids, di-caffeoyl- and di-feruloyl-quinic acids was identified as main components of the tea infusion, together with some flavonoids. Reconstitution of the same extracts in less polar or apolar solvents resulted in a different composition with no phenolics and a much lower concentration of artemisinin.

Molecular cloning and heterologous expression of a laccase gene from Pleurotus eryngii in free and immobilized Saccharomyces cerevisiae cells.

A full length cDNA encoding an extracellular laccase was isolated by reverse transcription polymerase chain reaction from the mycelia of the mushroom Pleurotus eryngii. The isolated sequence, denoted Ery3, encodes for a mature laccase isoenzyme of 531 amino acid residues with a predicted molecular weight of 56.6 kDa. All sequence motifs, being the signature sequences used to identify the laccases, were found in the Ery3 protein sequence. The Ery3 cDNA was expressed in Saccharomyces cerevisiae and the effects of copper concentration and cultivation temperature were investigated. S. cerevisiae cells were immobilized in calcium alginate gel and the optimal immobilization parameters for the enhanced production of laccase were determined. The immobilization was most effective with 3% sodium alginate, 0.1 M calcium chloride and an initial biomass of 4.5 x 10(8) cells. The enzyme yield obtained with immobilized cells (139 mU ml(-1)) showed a 1.6-fold increase compared to the highest yield obtained with free cells. The alginate beads showed good stability and retained 84% capacity of enzyme production after seven repeated cycles of batch fermentation. The immobilization system proved to increase the proteolytic stability of the recombinant Ery3 protein. To our knowledge, this is the first report on S. cerevisiae whole-cell immobilization for recombinant laccase production.