Oleocanthal is a minor constituent of olive oil with strong anti-inflammatory activities. Since the pathogenesis of many chronic diseases involves inflammatory and oxidative components, oleocanthal is a promising agent to prevent these conditions. This review aimed to summarise the current beneficial health effects of oleocanthal and the molecular basis of its biological actions. The anti-inflammatory, antioxidative, antimicrobial, anticancer and neuroprotective activities of oleocanthal have been examined by previous studies. Of these, studies on the anticancer effects have been the most extensive. Oleocanthal was reported to suppress melanoma, breast, liver, and colon cancer cells. Neurological studies focused on the effects of oleocanthal against Alzheimer’s disease. Oleocanthal improved clearance of the amyloid beta protein from neurons and reduced the inflammation of astrocytes. Despite the positive results, validation of the biological effects of oleocanthal in animal disease models is limited and should be emphasized in the future. As a conclusion, oleocanthal may act together with other bioactive compounds in olive oil to achieve its therapeutic potential. The use of oleocanthal alone as a single therapeutic measure awaits validation from future studies.

Obesity is a major risk factor for diabetes, and these two metabolic conditions cause significant healthcare burden worldwide. Chronic inflammation and increased oxidative stress due to exposure of cells to excess nutrients in obesity may trigger insulin resistance and pancreatic β-cell dysfunction. Tocotrienol, as a functional food component with anti-inflammatory, antioxidant, and cell signaling-mediating effects, may be a potential agent to complement the current management of obesity and diabetes. The review aimed to summarize the current evidence on the anti-obesity and antidiabetic effects of tocotrienol. Previous studies showed that tocotrienol could suppress adipogenesis and, subsequently, reduce body weight and fat mass in animals. This was achieved by regulating pathways of lipid metabolism and fatty acid biosynthesis. It could also reduce the expression of transcription factors regulating adipogenesis and increase apoptosis of adipocytes. In diabetic models, tocotrienol was shown to improve glucose homeostasis. Activation of peroxisome proliferator-activated receptors was suggested to be responsible for these effects. Tocotrienol also prevented multiple systemic complications due to obesity and diabetes in animal models through suppression of inflammation and oxidative stress. Several clinical trials have been conducted to validate the antidiabetic of tocotrienol, but the results were heterogeneous. There is no evidence showing the anti-obesity effects of tocotrienol in humans. Considering the limitations of the current studies, tocotrienol has the potential to be a functional food component to aid in the management of patients with obesity and diabetes.

Osteoarthritis is a major cause of morbidity among the elderly worldwide. It is a disease characterized by localized inflammation of the joint and destruction of cartilage, leading to loss of function. Impaired chondrocyte repair mechanisms, due to inflammation, oxidative stress and autophagy, play important roles in the pathogenesis of osteoarthritis. Olive and its derivatives, which possess anti-inflammatory, antioxidant and autophagy-enhancing activities, are suitable candidates for therapeutic interventions for osteoarthritis. This review aimed to summarize the current evidence on the effects of olive and its derivatives, on osteoarthritis and chondrocytes. The literature on animal and human studies has demonstrated a beneficial effect of olive and its derivatives on the progression of osteoarthritis. In vitro studies have suggested that the augmentation of autophagy (though sirtuin-1) and suppression of inflammation by olive polyphenols could contribute to the chondroprotective effects of olive polyphenols. More research and well-planned clinical trials are required to justify the use of olive-based treatment in osteoarthritis.

Tocotrienol (T3) is a subfamily of vitamin E known for its wide array of medicinal properties. This review aimed to summarize the health benefits of T3, particularly in prevention or treatment of non-communicable diseases (NCDs), including cardiovascular, musculoskeletal, metabolic, gastric, and skin disorders, as well as cancers. Studies showed that T3 could prevent various NCDs, by suppressing 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) in the mevalonate pathway, inflammatory response, oxidative stress, and alternating hormones. The efficacy of T3 in preventing/treating these NCDs is similar or greater compared to tocopherol (TF). TF may lower the efficacy of T3 because the efficacy of the combination of TF and T3 was lower than T3 alone in some studies. Data investigating the effects of T3 on osteoporosis, arthritis, and peptic ulcers in human are limited. The positive outcomes of T3 treatment obtained from the preclinical studies warrant further validation from clinical trials.Nutrients 2020, 12, 259 2 of 84 Nutrients 2020, 12, 259 4 of 84 the order δ > γ > β > α [45]. Using HepG2 cells, γT3 was shown to stimulate apolipoprotein B (Apo-B) degradation by decreasing its translocation into the endoplasmic reticulum (ER) lumen. This action eventually caused a reduction in the number of Apo-B in lipoprotein particles [46]. Other reports showed that γT3 and δT3 had the potential to reduce the hepatic TG synthesis and very-low-density lipoprotein (VLDL) secretion by suppressing expression of genes involved in lipid homeostasis, particularly the TG, cholesterol, and VLDL biosynthesis. Moreover, δT3 also promoted the efflux of LDL through LDL receptor expression [47]. A summary of the literature on effect of T3 supplementation on lipid profile of hypercholesterolemic model in vitro is shown in Table 1.Animal models of dyslipidemia have been used to investigate the effects of T3 on lipid profile. Several animals have been tested, including chicken, swine and rodents (rats, hamsters, guinea pigs). In chickens fed with a varying level of αTF and γT3, Qureshi et al. (1996) showed that αTF enhanced the inhibition of HMGCR by γT3. They further stipulated that the vitamin E mixture should contain 15-20% of αTF and approximately 60% of γT3 or δT3 for optimal anti-cholesterol effects [48]. In the subsequent study, demonstrated that combination of 50 ppm T3-rich fraction (TRF) and 50 ppm lovastatin was more effective in suppressing HMGCR activity compared to lovastatin alone in chickens. The combination also reduced serum TC and LDL-C, TG, Apo-B, thromboxane B 2 , and platelet factor 4 in contrast to individual treatment [49]. Using chicken supplemented with 50 ppm of δT3, Qureshi et al. (2011) further revealed that δT3 reduced TC and LDL-C besides suppressing the lipid elevating effects of dexamethasone and potentiated the TG-lowering effect of riboflavin [50]. Using genetically hypercholesterolemic swine, Qureshi et al. (1991) demonstrated the significant effect of TRF in lowering serum TC, LDL-C, Apo-B, thrombo...

Metabolic syndrome (MetS) and osteoporosis are two medical problems plaguing the ageing populations worldwide. Though seemingly distinctive to each other, metabolic derangements are shown to influence bone health. This review summarises the relationship between MetS and bone health derived from epidemiological studies and explains the mechanistic basis of this relationship. The discourse focuses on the link between MetS and bone mineral density, quantitative sonometric indices, geometry and fracture risk in humans. The interesting sex-specific trend in the relationship, probably due to factors related to body composition and hormonal status, is discussed. Mechanistically, each component of MetS affects the bone distinctly, forming a complex interacting network influencing the skeleton. Lastly, the effects of MetS management, such as pharmacotherapies, exercise and bariatric surgery, on bone, are presented. This review aims to highlight the significant relationship between MetS and bone, and proper management of MetS with the skeletal system in mind could prevent cardiovascular and bone complications.