Posidonia oceanica (L.) Delile Ethanolic Extract Modulates Cell Activities with Skin Health Applications.

Seagrasses are high plants sharing adaptive metabolic features with both terrestrial plants and marine algae, resulting in a phytocomplex possibly endowed with interesting biological properties. The aim of this study is to evaluate the in vitro activities on skin cells of an ethanolic extract obtained from the leaves of Posidonia oceanica (L.) Delile, family Potamogetonaceae, herein named Posidonia ethanolic extract (PEE). PEE showed high radical scavenging activity, high phenolic content, and resulted rich in chicoric acid, as determined through HPLC-MS analysis. The use of MTT assay on fibroblasts showed a PEE cytotoxicity threshold (IC05) of 50 µg/mL at 48 h, while a sub-toxic dose of 20 µg/mL induced a significant increase of fibroblast growth rate after 10 days. In addition, an ELISA assay revealed that PEE doses of 5 and 10 µg/mL induced collagen production in fibroblasts. PEE induced dose-dependent mushroom tyrosinase inhibition, up to about 45% inhibition at 1000 µg/mL, while 50% reduction of melanin was observed in melanoma cells exposed to 50 µg/mL PEE. Finally, PEE lipolytic activity was assessed by measuring glycerol release from adipocytes following triglyceride degradation. In conclusion, we have collected new data about the biological activities of the phytocomplex of P. oceanica seagrass on skin cells. Our findings indicate that PEE could be profitably used in the development of products for skin aging, undesired hyperpigmentation, and cellulite.

Antiproliferative hydroxy-fatty acids from the fodder legume Stylosanthes guianensis.

Stylosanthes guianensis is a fodder legume native from South America and widely grown worldwide. Dried plant material was purchased on the web and taxonomically identified by light and SEM microscopy, and morphological analysis of plants germinated from seeds. The plant was extracted with dichloromethane:2-propanol (9:1). Bioguided fractionation using calcein-AM cytotoxicity assay on HeLa and A431 tumor cells allowed to isolate a lipophilic fraction, endowed with strong cytotoxicity. By means of 1- and 2-D NMR, HPLC-MS, and HR-ESIMS it could be seen that the fraction was an inseparable mixture of complex lipids, mainly consisting of esterified 3-hydroxy fatty acids. Acidic methanolysis of the mixture yielded 3-OH C10 and C12 carboxylic acids, together with palmitic, stearic, and arachidonic acids. Mass values indicate the presence of dimeric and trimeric combinations of 3-hydroxy, C10/C12 acids, and C16/C18/C20 acids, linked via ester bond. Monomeric hydroxyl-fatty acids were also observed, in particular derivatives of mono-hydroxy and di-hydroxy linolenic, linoleic, and oleic acids. 3-O-acylated, esterified fatty acids are unusual in higher plants, and recall motifs of Gram-negative endotoxin lipid A. These oxylipins are likely to be responsible for the antiproliferative activity of S. guianensis, suggesting possible use of the plant in the development of antitumor drugs.

Oleuropein-Enriched Olive Leaf Extract Affects Calcium Dynamics and Impairs Viability of Malignant Mesothelioma Cells.

Malignant mesothelioma is a poor prognosis cancer in urgent need of alternative therapies. Oleuropein, the major phenolic of olive tree (Olea europaea L.), is believed to have therapeutic potentials for various diseases, including tumors. We obtained an oleuropein-enriched fraction, consisting of 60% w/w oleuropein, from olive leaves, and assessed its effects on intracellular Ca(2+) and cell viability in mesothelioma cells. Effects of the oleuropein-enriched fraction on Ca(2+) dynamics and cell viability were studied in the REN mesothelioma cell line, using fura-2 microspectrofluorimetry and MTT assay, respectively. Fura-2-loaded cells, transiently exposed to the oleuropein-enriched fraction, showed dose-dependent transient elevations of cytosolic Ca(2+) concentration ([Ca(2+)]i). Application of standard oleuropein and hydroxytyrosol, and of the inhibitor of low-voltage T-type Ca(2+) channels NNC-55-0396, suggested that the effect is mainly due to oleuropein acting through its hydroxytyrosol moiety on T-type Ca(2+) channels. The oleuropein-enriched fraction and standard oleuropein displayed a significant antiproliferative effect, as measured on REN cells by MTT cell viability assay, with IC50 of 22 µg/mL oleuropein. Data suggest that our oleuropein-enriched fraction from olive leaf extract could have pharmacological application in malignant mesothelioma anticancer therapy, possibly by targeting T-type Ca(2+) channels and thereby dysregulating intracellular Ca(2+) dynamics.