An efficient, economical synthesis of hydroxytyrosol and its protected forms via Baeyer–Villiger oxidation

Biosynthesis and Biotechnological Synthesis of Hydroxytyrosol

Hydroxytyrosol (HT), a plant-derived phenolic compound, is recognized for its potent antioxidant capabilities alongside a spectrum of pharmacological benefits, including anti-inflammatory, anti-cancer, anti-bacterial, and anti-viral properties. These attributes have propelled HT into the spotlight as a premier nutraceutical and food additive, heralding a new era in health and wellness applications. Traditional methods for HT production, encompassing physico-chemical techniques and plant extraction, are increasingly being supplanted by biotechnological approaches. These modern methodologies offer several advantages, notably environmental sustainability, safety, and cost-effectiveness, which align with current demands for green and efficient production processes. This review delves into the biosynthetic pathways of HT, highlighting the enzymatic steps involved and the pivotal role of genetic and metabolic engineering in enhancing HT yield. It also surveys the latest progress in the biotechnological synthesis of HT, examining innovative strategies that leverage both genetically modified and non-modified organisms. Furthermore, this review explores the burgeoning potential of HT as a nutraceutical, underscoring its diverse applications and the implications for human health. Through a detailed examination of both the biosynthesis and biotechnological advances in HT production, this review contributes valuable insights to the field, charting a course towards the sustainable and scalable production of this multifaceted compound.

Biomimetic synthesis of hydroxytyrosol from conversion of tyrosol by mimicking tyrosine hydroxylase

Hydroxytyrosol, one of the most powerful natural antioxidants, exhibits certificated benefits for human health. In this study, a biomimetic approach to synthesize hydroxytyrosol from the hydroxylation of tyrosol was established. EDTA-Fe²⁺ coordination complex served as an active center to simulate tyrosine hydroxylase. H₂O₂ and ascorbic acid were used as oxygen donor and hydrogen donor, respectively. Hydroxy radical and singlet oxygen contributed to active species. The biomimetic system displayed analogous component, structure, and activity with TyrH. Hydroxytyrosol titer of 21.59 mM, and productivity of 9985.92 mg·L^-1·h^-1 was achieved with 100 mM tyrosol as substrate. The proposed approach provided efficient and convenient route to quickly produce high amount of hydroxytyrosol.

Antioxidant and Biological Activities of Hydroxytyrosol and Homovanillic Alcohol Obtained from Olive Mill Wastewaters of Extra-Virgin Olive Oil Production

Some constituents of the Mediterranean diet, such as extra-virgin olive oil (EVOO) contain substances such as hydroxytyrosol (HT) and its metabolite homovanillic alcohol (HA). HT has aroused much interest due to its antioxidant activity as a radical scavenger, whereas only a few studies have been made on the HA molecule. Both chemical synthesis and extraction techniques have been developed to obtain these molecules, with each method having its advantages and drawbacks. In this study, we report the use of tyrosol from olive mill wastewaters as a starting molecule to synthesize HT and HA, using a sustainable procedure characterized by high efficiency and low cost. The effects of HT and HA were evaluated on two cell lines, THP-1 human leukemic monocytes and L-6 myoblasts from rat skeletal muscle, after treating the cells with a radical generator. Both HT and HA efficiently inhibited ROS production. In particular, HT inhibited the proliferation of the THP-1 leukemic monocytes, while HA protected L-6 myoblasts from cytotoxicity.

A Three-Step, Gram-Scale Synthesis of Hydroxytyrosol, Hydroxytyrosol Acetate, and 3,4-Dihydroxyphenylglycol

Hydroxytyrosol and two other polyphenols of olive tree, hydroxytyrosol acetate and 3,4-dihydroxyphenylglycol, are known for a wide range of beneficial activities in human health and prevention from diseases. The inability to isolate high, pure amounts of these natural compounds and the difficult and laborious procedures for the synthesis of them led us to describe herein an efficient, easy, cheap, and scaling up synthetic procedure, from catechol, via microwave irradiation.

Chemical, physical and biotechnological approaches to the production of the potent antioxidant hydroxytyrosol

Hydroxytyrosol (HT) is a polyphenol of interest to the food, feed, supplements and pharmaceutical sectors. It is one of the strongest known natural antioxidants and has been shown to confer other benefits such as anti-inflammatory and anti-carcinogenic properties, and it has the potential to act as a cardio- and neuroprotectant. It is known to be one of the compounds responsible for the health benefits of the Mediterranean diet. In nature, HT is found in the olive plant (Olea europaea) as part of the secoiridoid compound oleuropein, in its leaves, fruit, oil and oil production waste products. HT can be extracted from these olive sources, but it can also be produced by chemical synthesis or through the use of microorganisms. This review looks at the production of HT using plant extraction, chemical synthesis and biotechnological approaches.