Simultaneous Determination of Phenolic Compounds in Plasma by LC-ESI-MS/MS and Their Bioavailability after the Ingestion of Table Olives

Determination of pentacyclic triterpenes and polyphenols from table olives in colon and plasma and their chemopreventive effects on 1,2-dimethylhydrazine-induced preneoplastic lesions in rat colon

Table olives are a rich dietary source of pentacyclic triterpenes (PT) and polyphenols (P), many of which have demonstrated significant antiproliferative and proapoptotic activities. This study aimed to evaluate the effect of this food on the early stages of colon carcinogenesis induced by 1,2-dimethylhydrazine (DMH) at 20 mg kg-1. Male Sprague-Dawley rats were administered either water or a suspension of Arbequina table olives (OA; 3.85 g kg-1) by gavage at 10 mL kg-1 for 49 days. Each group was then divided into two subgroups that received subcutaneous injections of the carcinogen (DMH+/Olives- and DMH+/Olives+) or the solvent (DMH-/Olives- and DMH-/Olives+) on days 8, 15, and 22. Analysis by LC-MS of AO enabled us to calculate the administered doses of PT (12.38 mg kg-1) and P (4.02 g kg-1) as well as the colon content of these compounds. At the end of the intervention, we found 5.1% of PT and 0.2% of P of the administered dose in the colonic content of the DMH+/Olives+ group. The highest concentrations were for maslinic and oleanolic acids (321 ± 67 and 84.8 ± 14.3 nmol g-1, respectively) followed by hydroxytyrosol (3.31 ± 0.24 nmol g-1). The supplementation with AO reduced aberrant crypt foci by 54.1%, and mucin depleted foci by 35.7% compared to the control group. The daily consumption of table olives exerts chemopreventive activities by reducing preneoplastic intestinal lesions, which might be explained, at least in part, by the significant concentrations of PT and P remaining in the colon.

Comparison of In Vitro Biotransformation of Olive Polyphenols Between Healthy Young and Elderly

BACKGROUND

Olive leaves are a rich source of polyphenols, predominantly secoiridoids, flavonoids, and simple phenols, which exhibit various biological properties. Extracts prepared from olive leaves are associated with hypoglycemic, hypotensive, diuretic, and antiseptic properties. Upon ingestion, a substantial fraction of these polyphenols reaches the colon where they undergo extensive metabolism by the gut microbiota. Host characteristics, like age, can influence the composition of the gut microbiome, potentially affecting the biotransformation of these compounds. Therefore, it can be hypothesised that differences in the gut microbiome between young and elderly individuals may impact the biotransformation rate and the type and amount of metabolites formed.

METHODS

An in vitro biotransformation model was used to mimic the conditions in the stomach, small intestine and colon of two age groups of healthy participants (20-30 years old, ≥65 years old), using oleuropein as a single compound and an olive leaf extract as test compounds. The bacterial composition and metabolite content were investigated.

RESULTS

The study revealed that, while the same metabolites were formed in both age groups, in the young age group, less metabolite formation was observed, likely due to a reduced viable cell count. Most biotransformation reactions took place within the first 24 h of colon incubation, and mainly, deglycosylation, hydrolysis, flavonoid ring cleavage, and demethylation reactions were observed. A bacterial composition analysis showed a steep drop in α-diversity after 24 h of colon incubation, likely due to favourable experimental conditions for certain bacterial species.

CONCLUSIONS

Both age groups produced the same metabolites, suggesting that the potential for polyphenols to exert their health-promoting benefits persists in healthy older individuals.

Progress, pharmacokinetics and future perspectives of luteolin modulating signaling pathways to exert anticancer effects: A review

Luteolin (3, 4, 5, 7-tetrahydroxyflavone) are natural flavonoids widely found in vegetables, fruits and herbs, with anti-tumor, anti-inflammatory and antioxidant effects, and also play an anti-cancer effect in various cancers such as lung, breast, prostate, and liver cancer, etc. Specifically, the anti-cancer mechanism includes regulation of various signaling pathways to induce apoptosis of tumor cells, inhibition of tumor cell proliferation and metastasis, anti-angiogenesis, regulation of immune function, synergistic anti-cancer drugs and regulation of reactive oxygen species levels of tumor cells. Specific anti-cancer mechanisms include regulation of various signaling pathways to induce apoptosis, inhibition of tumor cell proliferation and metastasis, anti-angiogenesis, reversal of epithelial-mesenchymal transition, regulation of immune function, synergism with anti-cancer drugs and regulation of reactive oxygen species levels in tumor cells. This paper integrates the latest cutting-edge research on luteolin and combines it with the prospect of future clinical applications, aiming to explore the mechanism of luteolin exerting different anticancer effects through the regulation of different signaling pathways, so as to provide a practical theoretical basis for the use of luteolin in clinical treatment and hopefully provide some reference for the future research direction of luteolin.

Luteolin, a flavone ingredient: Anticancer mechanisms, combined medication strategy, pharmacokinetics, clinical trials, and pharmaceutical researches

Current pharmaceutical research is energetically excavating the pharmacotherapeutic role of herb-derived ingredients in multiple malignancies' targeting. Luteolin is one of the major phytochemical components that exist in various traditional Chinese medicine or medical herbs. Mounting evidence reveals that this phytoconstituent endows prominent therapeutic actions on diverse malignancies, with the underlying mechanisms, combined medication strategy, and pharmacokinetics elusive. Additionally, the clinical trial and pharmaceutical investigation of luteolin remain to be systematically delineated. The present review aimed to comprehensively summarize the updated information with regard to the anticancer mechanism, combined medication strategies, pharmacokinetics, clinical trials, and pharmaceutical researches of luteolin. The survey corroborates that luteolin executes multiple anticancer effects mainly by dampening proliferation and invasion, spurring apoptosis, intercepting cell cycle, regulating autophagy and immune, inhibiting inflammatory response, inducing ferroptosis, and pyroptosis, as well as epigenetic modification, and so on. Luteolin can be applied in combination with numerous clinical anticarcinogens and natural ingredients to synergistically enhance the therapeutic efficacy of malignancies while reducing adverse reactions. For pharmacokinetics, luteolin has an unfavorable oral bioavailability, it mainly persists in plasma as glucuronides and sulfate-conjugates after being metabolized, and is regarded as potent inhibitors of OATP1B1 and OATP2B1, which may be messed with the pharmacokinetic interactions of miscellaneous bioactive substances in vivo. Besides, pharmaceutical innovation of luteolin with leading-edge drug delivery systems such as host-guest complexes, nanoparticles, liposomes, nanoemulsion, microspheres, and hydrogels are beneficial to the exploitation of luteolin-based products. Moreover, some registered clinical trials on luteolin are being carried out, yet clinical research on anticancer effects should be continuously promoted.

Pharmacokinetics of Hydroxytyrosol and Its Sulfate and Glucuronide Metabolites after the Oral Administration of Table Olives to Sprague-Dawley Rats

The pharmacokinetics (PK) of hydroxytyrosol and its metabolites were characterized following oral administration to Sprague-Dawley rats of 3.85 and 7.70 g of destoned Arbequina table olives/kg. Plasma samples were analyzed using a fully validated method consisting of liquid extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Noncompartmental PK analysis of hydroxytyrosol demonstrated linear PK between doses of 2.95 and 5.85 mg hydroxytyrosol/kg. Half-life was approximately 2.5 h, while mean residence time was around 4 h. Clearance occurred by conversion to two sulfate and two glucuronide conjugates. The area under the plasma concentration-time curve (AUC) ratios of metabolites versus parent hydroxytyrosol was approximately 7-9-fold for the sulfate and below 0.25 for the glucuronide, indicating sulfation as the predominant metabolic pathway. Despite extensive metabolism, hydroxytyrosol remained in plasma for up to 8 h with AUCs of 4293 and 8919 min·nmol/L for the doses of 3.85 and 7.70 g/kg, respectively. Therefore, table olives provide a more sustained plasma profile than other foods containing hydroxytyrosol, which may enhance its health-protecting activities.

Correlation Analysis between Dietary Intake of Tyrosols and Their Food Sources and Urinary Excretion of Tyrosol and Hydroxytyrosol in a European Population

This study analyzed the correlations between the acute and habitual intake of dietary tyrosols, their main food sources, and 24 h urine excretions of tyrosol (Tyr) and hydroxytyrosol (OHTyr) in participants from the European Prospective Investigation into Cancer and Nutrition study (EPIC). Participants (n = 419) were healthy men and women aged from 34 to 73 years from 8 EPIC centers belonging to France, Italy, and Germany. Acute and habitual dietary data were collected using a standardized 24 h dietary recall software and validated country-specific dietary questionnaires, respectively. The intake of 13 dietary tyrosols was estimated using the Phenol-Explorer database. Excretions of Tyr and OHTyr in a single 24 h urine sample were analyzed using tandem mass spectrometry. Urinary excretions of Tyr, OHTyr, and their sum (Tyr + OHTyr) correlated more strongly with their corresponding acute (rhopartial~0.63) rather than habitual intakes (rhopartial~0.47). In addition, individual and combined urinary excretions of Tyr and OHTyr were weakly to moderately correlated with the acute and habitual intake of other individual tyrosol precursors (rhopartial = 0.10-0.44) and especially with major food sources, such as wine (rhopartial = 0.41-0.58), olive oil (rhopartial = 0.25-0.44), and beer (rhopartial = 0.14-0.23). Urinary Tyr + OHTyr excretions were similarly correlated with the acute intake of total tyrosols but differently correlated with food sources among countries. Based on these results, we conclude that 24 h urinary excretions of Tyr + OHTyr could be proposed as biomarkers of total tyrosol intake, preferably for acute intakes.

Table olive elicits antihypertensive activity in spontaneously hypertensive rats

BACKGROUND

Table olives are a food with a high content of bioactive compounds with cardioprotective properties, such as oleic acid, polyphenols, and pentacyclic triterpenes. Here, we investigate the effect of the intake of table olives on blood pressure (BP) and body weight in spontaneously hypertensive rats (SHR) and their normotensive controls, Wistar Kyoto (WKY) rats. 'Arbequina' table olives (3.85 g kg^-1 ) were administered by gavage to SHR and WKY rats in short-term (1 day) and long-term (7 weeks) experiments. BP was measured by the tail-cuff method, and polyphenols and triterpenes were determined in olives and plasma by liquid chromatography-mass spectrometry.

RESULTS

Administration of 'Arbequina' olives to WKY rats did not exert any change in BP in any of the experiments. However, in SHR, the single dose induced a transient reduction in BP of approximately 15 mmHg, from the second to the tenth hour after the administration. In the long-term assay, a similar decrease was established in the second week and was maintained throughout the experiment. Moreover, the daily administration of olives to rats did not affect their body weight when compared with controls in either the WKY rats or SHR. The determination of polyphenols and triterpenes in plasma indicated that, at the end of the experiment, only maslinic acid, oleanolic acid, hydroxytyrosol, and luteolin were found, all of them being compounds with already described capacity to decrease BP.

CONCLUSION

The results suggest that the daily intake of table olives could decrease BP in hypertension without affecting body weight, indicating that table olives could contribute to improving cardiovascular health. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Amelioration of radiation-induced liver damage by p-coumaric acid in mice

Radiation-induced liver damage (RILD) is a spiny problem in radiotherapy or other circumstances that exposure to radiation. The need for radioprotective agent is increasing to protect liver tissue. This study aimed to explore the hepatoprotective effect of p-coumaric acid (CA) against RILD. C57BL/6 male mice were exposed to 4 Gy irradiation and administrated with CA for 4 days starting on the same day of irradiation. Mice were sacrificed to obtain blood and liver tissues on day 3.5 or 14 post irradiation, respectively. The blood and liver tissues were collected. As compared with the only irradiated group, CA supplementation improved liver morphology, decreased serum alanine aminotransferase and aspartate aminotransferase, inhibited BCL2-associated X (BAX) protein expression, and improved the mice hematopoietic function. CA at the dose of 100 mg/kg body weight showed better effect compared to the other doses. Thus, CA might possess potential to protect against RILD.

Recent Analytical Approaches for the Study of Bioavailability and Metabolism of Bioactive Phenolic Compounds

The study of the bioavailability of bioactive compounds is a fundamental step for the development of applications based on them, such as nutraceuticals, functional foods or cosmeceuticals. It is well-known that these compounds can undergo metabolic reactions before reaching therapeutic targets, which may also affect their bioactivity and possible applications. All recent studies that have focused on bioavailability and metabolism of phenolic and terpenoid compounds have been developed because of the advances in analytical chemistry and metabolomics approaches. The purpose of this review is to show the role of analytical chemistry and metabolomics in this field of knowledge. In this context, the different steps of the analytical chemistry workflow (design study, sample treatment, analytical techniques and data processing) applied in bioavailability and metabolism in vivo studies are detailed, as well as the most relevant results obtained from them.