Oleocanthal, a phenolic component of extra-virgin olive oil, has been recently linked to reduced risk of Alzheimer's disease (AD), a neurodegenerative disease that is characterized by accumulation of β-amyloid (Aβ) and tau proteins in the brain. However, the mechanism by which oleocanthal exerts its neuroprotective effect is still incompletely understood. Here, we provide in vitro and in vivo evidence for the potential of oleocanthal to enhance Aβ clearance from the brain via up-regulation of P-glycoprotein (P-gp) and LDL lipoprotein receptor related protein-1 (LRP1), major Aβ transport proteins, at the blood-brain barrier (BBB). Results from in vitro and in vivo studies demonstrated similar and consistent pattern of oleocanthal in controlling Aβ levels. In cultured mice brain endothelial cells, oleocanthal treatment increased P-gp and LRP1 expression and activity. Brain efflux index (BEI%) studies of (125)I-Aβ40 showed that administration of oleocanthal extracted from extra-virgin olive oil to C57BL/6 wild-type mice enhanced (125)I-Aβ40 clearance from the brain and increased the BEI% from 62.0 ± 3.0% for control mice to 79.9 ± 1.6% for oleocanthal treated mice. Increased P-gp and LRP1 expression in the brain microvessels and inhibition studies confirmed the role of up-regulation of these proteins in enhancing (125)I-Aβ40 clearance after oleocanthal treatment. Furthermore, our results demonstrated significant increase in (125)I-Aβ40 degradation as a result of the up-regulation of Aβ degrading enzymes following oleocanthal treatment. In conclusion, these findings provide experimental support that potential reduced risk of AD associated with extra-virgin olive oil could be mediated by enhancement of Aβ clearance from the brain.

The proto-oncogene receptor tyrosine kinase c-Met encodes the high-affinity receptor for hepatocyte growth factor (HGF). Dysregulation of the HGF-c-Met pathway plays a significant oncogenic role in many tumors. Overexpression of c-Met is a prognostic indicator for some transitional cell carcinomas. Extra-virgin olive oil (EVOO) provides a variety of minor phenolic compounds with beneficial properties. (-)-Oleocanthal (1) is a naturally occurring minor secoiridoid isolated from EVOO, which showed potent anti-inflammatory activity via its ability to inhibit COX-1 and COX-2. It altered the structure of neurotoxic proteins believed to contribute to the debilitating effects of Alzheimer's disease. Computer-Assisted Molecular Design (CAMD) identified 1 as a potential virtual c-Met inhibitor hit. Oleocanthal inhibited the proliferation, migration, and invasion of the epithelial human breast and prostate cancer cell lines MCF7, MDA-MB-231, and PC-3, respectively, with an IC (50) range of 10-20 µM, and demonstrated anti-angiogenic activity via downregulating the expression of the microvessel density marker CD31 in endothelial colony forming cells with an IC (50) of 4.4 µM. It inhibited the phosphorylation of c-Met kinase IN VITRO in the Z'-LYTE™ assay, with an IC (50) value of 4.8 µM. (-)-Oleocanthal and EVOO can have potential therapeutic use for the control of c-Met-dependent malignancies.

Numerous clinical and preclinical studies have suggested several health promoting effects for the dietary consumption of extra-virgin olive oil (EVOO) that could protect and decrease the risk of developing Alzheimer’s disease (AD). Moreover, recent studies have linked this protective effect to oleocanthal, a phenolic secoiridoid component of EVOO. This protective effect of oleocanthal against AD has been related to its ability to prevent amyloid-β (Aβ) and tau aggregation in vitro, and enhance Aβ clearance from the brains of wild type mice in vivo; however, its effect in a mouse model of AD is not known. In the current study, we investigated the effect of oleocanthal on pathological hallmarks of AD in TgSwDI, an animal model of AD. Mice treatment for 4 weeks with oleocanthal significantly decreased amyloid load in the hippocampal parenchyma and microvessels. This reduction was associated with enhanced cerebral clearance of Aβ across the blood-brain barrier (BBB). Further mechanistic studies demonstrated oleocanthal to increase the expression of important amyloid clearance proteins at the BBB including P-glycoprotein and LRP1, and to activate the ApoE-dependent amyloid clearance pathway in the mice brains. The anti-inflammatory effect of oleocanthal in the brains of these mice was also obvious where it was able to reduce astrocytes activation and IL-1β levels. Finally, we could recapitulate the observed protective effect of oleocanthal in an in vitro human-based model, which could argue against species difference in response to oleocanthal. In conclusion, findings from in vivo and in vitro studies provide further support for the protective effect of oleocanthal against the progression of AD.

The isolation of the new enantiomers of 8-hydroxymanzamine A (1), manzamine F (2), along with the unprecedented manzamine dimer, neo-kauluamine from an undescribed genus of Indo-Pacific sponge (family Petrosiidae, order Haplosclerida) is reported. The relative stereochemistry of neo-kauluamine was established through detailed analysis of NOE-correlations combined with molecular modeling. The significance of the manzamines as in vivo antimalarial agents with superior activity to the clinically used drugs artemisinin and chloroquine is discussed along with the activity in vitro against the AIDS-opportunistic infectious diseases tuberculosis and toxoplasmosis. Reexamination of the sponges identified as Prianos, and Pachypellina, in earlier publications has confirmed that these are members of the same genus as the sponge described here, but differ at the species level.