Bioavailability and nutrikinetics of rosemary tea phenolic compounds in humans

Eco-friendly carboxymethyl cellulose films incorporated with phenolic compounds from hydrodistillation wastewater of rosemary essential oil

The food packaging industry seeks innovative materials that enhance food preservation while promoting sustainability. This study investigated the development of carboxymethyl cellulose (CMC) films incorporating both rosemary essential oil (EO) and phenolic compounds extracted from the hydrodistillation wastewater of rosemary. The aqueous extract (AE), rich in rosmarinic acid, caffeic acid, chlorogenic acid, vanillic acid, luteolin, rosmanol, and carnosic acid, was used to improve the bioactive properties of the films. Four formulations were produced: CMC (control), CMC/EO (with essential oil), CMC/AE (with aqueous extract), and CMC/EO/AE (with both EO and AE). The incorporation of EO and AE increased the film thickness and altered microstructural properties, with EO-containing films exhibiting larger voids due to oil droplet coalescence. Films with AE showed a significantly higher yellowing index and superior UV barrier properties, which could protect light-sensitive foods. FTIR and XRD analyses confirmed successful incorporation of bioactive compounds, while solubility tests revealed that EO-containing films were fully soluble, whereas AE-containing films exhibited reduced solubility (~50 %), enhancing their potential for moisture-sensitive food applications. EO increased film flexibility by 45 %, whereas AE-containing films demonstrated improved antioxidant activity, with FRAP and TEAC values approximately 300 % and 700 % higher, respectively, compared to the control. These films have potential for food packaging applications, particularly for lipid-rich foods prone to oxidative degradation (e.g., nuts, dairy, processed meats) and fresh produce susceptible to photodegradation. By utilizing a by-product of the essential oil industry, this study contributes to the development of sustainable and functional food packaging solutions.

p-Hydroxycinnamic Acids: Advancements in Synthetic Biology, Emerging Regulatory Targets in Gut Microbiota Interactions, and Implications for Animal Health

p-hydroxycinnamic acids (p-HCAs), a class of natural phenolic acid compounds extracted from plant resources and widely distributed, feature a C6-C3 phenylpropanoid structure. Their antioxidant, anti-inflammatory, and antibacterial activities have shown great potential for applications in food and animal feed. The interactions between p-HCAs and the gut microbiota, as well as their subsequent effects on animal health, have increasingly attracted the attention of researchers. In the context of a greener and safer future, the progress and innovation in biosynthetic technology have occupied a central position in ensuring the safety of food and feed. This review emphasizes the complex mechanisms underlying the interactions between p-HCAs and the gut microbiota, providing a solid explanation for the remarkable bioactivities of p-HCAs and their subsequent impact on animal health. Furthermore, it explores the advancements in the synthetic biology of p-HCAs. This review could aid in a basis for better understanding the underlying interactions between p-HCAs and gut microbiota and animal health.

Modulation of Gut Microbiota Composition and Microbial Phenolic Catabolism of Phenolic Compounds from Achillea millefolium L. and Origanum majorana L

The impact of the nonbioaccessible fraction of two phenolic-rich extracts from Achillea millefolium L. (yarrow) and Origanum majorana L. (marjoram) on the modulation of the human gut microbiota was investigated in vitro. Microbial metabolism of the phenolic compounds was also addressed. In general, phenolic acids or O-glycosidic flavones quickly disappeared, in contrast to methoxy- or C-glycosidic flavonoids. This colonic metabolism yielded phloroglucinol, 3,4-dimethoxyphenylacetic acid, 3-(4-hydroxyphenyl)-propionic acid, and 4-hydroxybenzoic acid as the main metabolites of the microbial catabolism of rosmarinic acid or caffeoylquinic acids, among others. The 16S rRNA gene sequencing showed that the most promising modulatory effect was related to the increase in Bifidobacterium spp., Collinsella spp., Romboutsia, and Akkermansia muciniphila for both plant extracts, along with Blautia spp. and Dialister for yarrow extract. This beneficial modulation was accompanied by the increase in butyric acid production, highlighting the potential prebiotic-like effect on the gut microbiota of these two previously unstudied edible plants.

Rosmarinic Acid: A Potential Therapeutic Agent in Gastrointestinal Cancer Management-A Review

Gastrointestinal cancers are still the leading cause of death worldwide. This is related, among other things, to the non-specific symptoms, especially in the initial stages, and also to the limited possibilities for treatment. Therefore, research is still being conducted to improve the detection of this type of cancer and increase the effectiveness of therapy. The potential application of natural compounds in cancer management deserves special attention. In the group of such products, there are polyphenolic compounds that reveal, e.g., anti-oxidative, anti-carcinogenic, anti-inflammatory, anti-diabetic, and neuroprotective properties. One of these polyphenols is rosmarinic acid, commonly found in plants such as the Boraginaceae and Nepetoideae subfamilies of the Lamiaceae (mint) family. A number of studies have considered the positive effects of rosmarinic acid in the treatment of many cancers, including gastrointestinal ones such as oral, stomach, pancreas, colon, and liver cancers. The main aim of this paper was to summarize the mechanisms of action of rosmarinic acid in gastrointestinal cancers.

A critical examination of human data for the biological activity of phenolic acids and their phase-2 conjugates derived from dietary (poly)phenols, phenylalanine, tyrosine and catecholamines

Free or conjugated aromatic/phenolic acids arise from the diet, endogenous metabolism of catecholamines (adrenaline, noradrenaline, dopamine), protein (phenylalanine, tyrosine), pharmaceuticals (aspirin, metaprolol) plus gut microbiota metabolism of dietary (poly)phenols and undigested protein. Quantitative data obtained with authentic calibrants for 112 aromatic/phenolic acids including phase-2 conjugates in human plasma, urine, ileal fluid, feces and tissues have been collated and mean/median values compared with in vitro bioactivity data in cultured cells. Ca 30% of publications report bioactivity at ≤1 μmol/L. With support from clinical studies, it appears that the greatest benefit might be produced in vascular tissues by C6-C3 metabolites, including some of gut microbiota origin and some phase-2 conjugates, 15 of which are 3',4'-disubstituted with multiple sources including caffeic acid and hesperetin, plus one unsubstituted and two mono-substituted examples which can originate from protein. There is an unexamined potential for synergy. Free-living and washout plasma data are scarce. Some metabolites have been overlooked, notably phenyl-lactic, phenyl-hydracrylic and phenyl-propanoic acids, especially those from amino acids plus glycine, hydroxy-glycine and glutamine conjugates. Phenolic acids and conjugates from multiple sources exhibit biological activities, some of which are likely relevant in vivo and link to biomarkers of health. Further targeted studies are justified.

An untargeted metabolomics approach applied to the study of the bioavailability and metabolism of three different bioactive plant extracts in human blood samples

Advances in the understanding of bioavailability and metabolism of bioactive compounds have been achieved primarily through targeted or semi-targeted metabolomics approaches using the hypothesis of potential metabolized compounds. The recent development of untargeted metabolomics approaches can present great advantages in this field, such as in the discovery of new metabolized compounds or to study the metabolism of compounds from multiple matrices simultaneously. Thus, this study proposes the use of an untargeted metabolomics strategy based on HPLC-ESI-QTOF-MS for the study of bioavailability and metabolism of bioactive compounds from different vegetal sources. Specifically, this study has been applied to plasma samples collected in an acute human intervention study using three matrices (Hibiscus sabdariffa, Silybum marianum and Theobroma cacao). This approach allowed the selection of those significant variables associated with exogenous metabolites derived from the consumption of bioactive compounds for their subsequent identification. As a result, 14, 25 and 3 potential metabolites associated with supplement intake were significantly detected in the plasma samples from volunteers who ingested the H. sabdariffa (HS), S. marianum (SM) and T. cacao (TC) extracts. Furthermore, Tmax values have been computed for each detected compound. The results highlight the potential of untargeted metabolomics for rapid and comprehensive analysis when working with a wide range of exogenous metabolites from different plant sources in biological samples.

Rosemary (Rosmarinus officinalis L.) polyphenols and inflammatory bowel diseases: Major phytochemicals, functional properties, and health effects

Major polyphenols in Rosmarinus officinalis L. primarily consist of phenolic acids, phenolic diterpenes, and flavonoids, all of which have pharmacological properties including anti-inflammatory and antibacterial characteristics. Numerous in vitro and animal studies have found that rosemary polyphenols have the potential to decrease the severity of intestinal inflammation. The beneficial effects of rosemary polyphenols were associated with anti-inflammatory properties, including improved gut barrier (increased mucus secretion and tight junction), increased antioxidant enzymes, inhibiting inflammatory pathways and cytokines (downregulation of NF-κB, NLRP3 inflammasomes, STAT3 and activation of Nrf2), and modulating gut microbiota community (increased core probiotics and SCFA-producing bacteria, and decreased potential pathogens) and metabolism (changes in SCFA and bile acid metabolites). This paper provides a better understanding of the anti-inflammatory properties of rosemary polyphenols and suggests that rosemary polyphenols might be employed as strong anti-inflammatory agents to prevent intestinal inflammation and lower the risk of inflammatory bowel disease and related diseases.

Optimizing the ultrasonic extraction of polyphenols from mango peel and investigating the characteristics, antioxidant activity and storage stability of extract nanocapsules in maltodextrin/whey protein isolate

In this study, the extraction and nanoencapsulation of mango peel extract (MPE) were investigated to enhance its stability and preserve its antioxidant properties. Initially, using the central composite design (CCD)-response surface methodology (RSM), optimal conditions for the extraction of MPE via an ultrasonic system were determined to be a temperature of 10.53 °C, a time of 34.35 min, and an ethanol concentration of 26.62 %. Subsequently, the extracted extract was spray-dried and nanoencapsulated using three types of coatings: maltodextrin, whey protein isolate (WPI), and their combination. The results showed that nanoencapsulation led to a significant improvement in the stability of phenolic compounds in the extract during storage compared to free extract. Furthermore, capsules prepared with the combined coating exhibited the highest levels of phenolic compounds and antioxidant activity. Therefore, it can be concluded that nanoencapsulation can serve as an effective method for preserving the bioactive properties of MPE.

Preparation, chemical profiles, antioxidative activities, and angiotensin-converting enzyme 2 inhibitory effect of date fruit vinegar

Date palm (Phoenix dactylifera L.) is an important commercial crop extensively consumed as a staple food and has been applied in many ethnomedical systems. Fruit vinegar is a preservative, condiment, and beverage with a spectrum of health benefits. Studies about the preparation, chemical profiles, and bioactivities of date fruit vinegar (DFV) are fundamental requirements for industrialization production. This study focused on the lab-scaled producing conditions, chemical profiles of DFV, and its bioactivities in vitro. According to the results, a date wine containing 9.75% methanol was obtained by yeast fermenting the enzyme-hydrolyzed date juice with 23.11% ± 0.39% of total sugar content. The optimized acidic fermentation conditions were an inoculation amount of 0.02%, a fermentation temperature of 31.14°C, and an initial alcohol content of 7.78%. Total acidity and total phenolic contents of the DFV were 7.74% ± 0.29% and 1.44 mg gallic acid equivalent/mL, respectively. In total, 32 organic acids were quantitated in the unaged DFV, with acetic, L-malic, and oxoglutaric acids as the predominant compounds. A total of 930 volatiles were identified in the DFV, including 186 esters, 177 terpenoids, and 148 heterocyclic compounds. There are 18 phenolic acids presented in the DFV. In addition, 42 flavonoids were quantitated in the DFV, including catechin, taxifolin, and cynaroside. The results of free radical scavenging activities and reducing power demonstrated that the DFV displayed good antioxidant properties. The DFV also acted well on angiotensin-converting enzyme 2 inhibition. These results suggest that the DFV can be industrially developed as a dietary supplement.

Bioavailability of bioactive compounds in Hibiscus sabdariffa beverage as a potential anti-inflammatory

The absorption and metabolism of bioactive compounds (BCs) in a Hibiscus sabdariffa drink (HbD) were evaluated by the in vivo bioavailability of organic acids (OA) and phenolic compounds (PC's). An acute single-blind clinical study in humans was conducted. Twelve volunteers consumed a HbD and a control drink (CD). Urine and plasma samples were taken after consuming both beverages. OA and PC's of the beverages (HbD and CD) and the biological samples (urine and plasma) were characterized by HPLC-DAD-MS. Thirthy-eight compounds in HbD and four CD were detected and quantified, equivalent to 937.37 mg and 1.22 mg per 60 mL, respectively. Hibiscus acid was the most abundant OA in both drinks. Additionally, hydroxycinnamic acids, flavonoids, anthocyanins, and anthocyanidins were also detected in HbD, although their amount represented 10% of the total BCs. 25 different metabolites were identified, 15 in urine and 23 in plasma. The microbiota extensively biotransformed PCs and their amount was lower than organic acids, particularly hibiscus acid and hydroxycitric acid. The colonic metabolites derived from PCs and organic acids would be behind the anti-inflammatory bioactivity described for Hibiscus sabdariffa L. (Malvaceae family). However, further studies are necessary to evaluate the metabolites responsible for their anti-inflammatory activity.

Next-generation analytical platforms for antioxidant capacity assessment: The urge for realistic and physiologically relevant methods

Bioactive compounds, such as carotenoids, alkaloids, and phenolics, are well known because of their alleged health benefits when consumed regularly in a balanced healthy diet. Some well-documented bioactivities are antioxidant, antihypertensive, antihyperglycemic, antilipidemic, anti-obesity, anti-inflammatory, and antimicrobial capacities. Trying to associate the chemical composition of distinct sources and their bioactivity using in vitro methods, several assays have been developed, implemented, and optimised to recapitulate human physiological conditions. However, in most cases, pitfalls are apparent, and no single test tube-based assay can predict in vivo responses. The need for a more physiologically relevant cell-based method to evaluate the antioxidant capacity of putative antioxidants is apparent. Therefore, in this Review, the current state-of-the-art in food science and nutrition is aligned with cell biology/bioengineering approaches to propose combining in vitro digestion and absorption to obtain a bioavailable fraction containing antioxidants. Overall, human plasma, 2-dimensional human cell lines, such as erythrocytes, lymphocytes, hepatocytes, enterocytes and, ultimately, 3-dimensional spheroids (organoids) could be used as biologically relevant models to assess the antioxidant activity of compounds, foods, and nutraceuticals. This versatile approach is deemed suitable, accurate, reproducible, and physiologically relevant to evaluate the protective effects of antioxidants against ROS-mediated oxidation in vitro.

Microbial degradation and transformation of PPCPs in aquatic environment: A review

The Pharmaceuticals and Personal Care Products (PPCPs) presence at harmful levels has been identified in aquatic ecosystems all over the world. Currently, PPCPs are more common in aquatic regions and have been discovered to be extremely harmful to aquatic creatures. Waste-water treatment facilities are the primary cause of PPCPs pollution in aquatic systems due to their limited treatment as well as the following the release of PPCPs. The degree of PPCPs elimination is primarily determined by the method applied for the remediation. It must be addressed in an eco-friendly manner in order to significantly improve the environmental quality or, at the very least, to prevent the spread as well as effects of toxic pollutants. However, when compared to other methods, environmentally friendly strategies (biological methods) are less expensive and require less energy. Most biological methods under aerobic conditions have been shown to degrade PPCPs effectively. Furthermore, the scientific literature indicates that with the exception of a few extremely hydrophobic substances, biological degradation by microbes is the primary process for the majority of PPCPs compounds. Hence, this review discusses about the optimistic role of microbe concerned in the degradation or transformation of PPCPs into non/less toxic form in the polluted environment. Accordingly, more number of microbial strains has been implicated in the biodegradation/transformation of harmful PPCPs through a process termed as bioremediation and their limitations.

Beneficial effects of phenolic compounds: native phenolic compounds vs metabolites and catabolites

In the human body, the positive effects of phenolic compounds are increasingly observed through their presence in tissues and organs in their native form or in the form of metabolites or catabolites formed during digestion, microbial metabolism, and host biotransformation. The full extent of these effects is still unclear. The aim of this paper is to review the current knowledge of beneficial effects of native phenolic compounds or their metabolites and catabolites focusing on their role in the health of the digestive system, including disorders of the gastrointestinal and urinary tracts and liver. Studies are mostly connecting beneficial effects in the gastrointestinal and urinary tract to the whole food rich in phenolics, or to the amount of phenolic compounds/antioxidants in food. Indeed, the bioactivity of parent phenolic compounds should not be ignored due to their presence in the digestive tract, and the impact on the gut microbiota. However, the influence of their metabolites and catabolites might be more important for the liver and urinary tract. Distinguishing between the effects of parent phenolics vs metabolites and catabolites at the site of action are important for novel areas of food industry, nutrition and medicine.

Rosmarinic Acid and Related Dietary Supplements: Potential Applications in the Prevention and Treatment of Cancer

Cancer constitutes a severe threat to human health and quality of life and is one of the most significant causes of morbidity and mortality worldwide. Natural dietary products have drawn substantial attention in cancer treatment and prevention due to their availability and absence of toxicity. Rosmarinic acid (RA) is known for its excellent antioxidant properties and is safe and effective in preventing and inhibiting tumors. This review summarizes recent publications on culture techniques, extraction processes, and anti-tumor applications of RA-enriched dietary supplements. We discuss techniques to improve RA bioavailability and provide a mechanistic discussion of RA regarding tumor prevention, treatment, and adjuvant therapy. RA exhibits anticancer activity by regulating oxidative stress, chronic inflammation, cell cycle, apoptosis, and metastasis. These data suggest that daily use of RA-enriched dietary supplements can contribute to tumor prevention and treatment. RA has the potential for application in anti-tumor drug development.

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.

Ultrasound-assisted extraction of functional compound from mulberry (Morus alba L.) leaf using response surface methodology and effect of microencapsulation by spray drying on quality of optimized extract

This study aimed to optimize the ultrasound-assisted extraction (UAE) condition of mulberry leaf extract (MLE) using response surface methodology and to microencapsulate MLE by spray drying using different coating materials and ratios of coating material and MLE. The extraction results showed that MLE from condition of 60 °C (X₁, temperature), 30 min (X₂, time) and 60% v/v (X₃, ethanol concentration) exhibited the highest bioactive compound and antioxidant activity (DPPH and FRAP assay). Based on this optimal condition, MLE was further encapsulated by spray drying. It was found that MLE encapsulated with resistant maltodextrin at ratio of MLE and resistant maltodextrin 1:1 (w/w) showed the highest encapsulation yield (%) and encapsulation efficiency (%). Water solubility, moisture content and water activity were non-significant (p > 0.05) among the microcapsules. The scanning electron microscope (SEM) revealed that the types of coating material affected their microstructures and microcapsules prepared by resistant maltodextrin as coating material had a spherical shape, smooth surface and less shrinkage than microcapsules prepared by maltodextrin and gum arabic which had rough surfaces. The highest antioxidant activity was obtained from microcapsule prepared by gum arabic at ratio of MLE and gam arabic 1:2 (w/w). In conclusion, optimal condition from UAE and encapsulation by spray drying suggest the critical potential for production of functional food with improved bioactive compound stability and maximized antioxidant activity.

LC-MS/MS-QTOF Screening and Identification of Phenolic Compounds from Australian Grown Herbs and Their Antioxidant Potential

Culinary spices and herbs have been used to impart a characteristic flavour and aroma in food due to their appealing fragrance. Recently, bioactive compounds from herbs, especially phenolics, have gained much attention due to their potential health outcomes. The aim of this study was to characterize and quantify the phenolic compounds from 10 widely used Australian-grown herbs (oregano, rosemary, bay, basil, sage, fenugreek, dill, parsley, mint and thyme). For this purpose, liquid chromatography mass spectrometry (LC-MS) was used for the complete profiling of polyphenolic compounds and quantification of abundant phenolic compounds was completed with high-performance liquid chromatography—photodiode array detection (HPLC-PDA). Polyphenols from Australian-grown herbs were estimated through total phenolic content (TP), total flavonoids (TF) and total tannins (TT) along with their in-vitro antioxidant activities. Oregano and mint were estimated with the highest value of TP (140.59 ± 9.52 and 103.28 ± 8.08 mg GAE/g, milligram gallic acid equivalent/gram) while rosemary and mint had the highest TF (8.19 ± 0.74 and 7.05 ± 0.43 mg QE (quercetin equivalent)/g). In this study, eighty-four (84) phenolic compounds were screened and confirmed through LC-MS/MS by comparing their masses and fragmentation pattern with published libraries. The results of this study validate the use of these herbs as bioactives and their positive impact on human health.

Antidiabetic potential of dietary polyphenols: A mechanistic review

Diabetes is a metabolic disorder that has caused enormous harm to the public health worldwide. In this study, we evaluated the potential of phenolic compounds on diabetes management, addressing their mechanisms of action, in addition to discussing the digestion, absorption, metabolism, bioavailability, and toxic effects of these compounds. The intake of phenolic compounds can play a fundamental role on diabetes management, since they can reduce blood glucose levels, oxidative stress, protein glycation, inhibit the activity of dipeptidyl peptidase - IV and other key enzymes related to carbohydrate metabolism, activate various biochemical pathways to improve pancreatic β-cell functions, increase insulin secretion, and improve insulin resistance. In this way, they can be considered a potential strategy in the development of pharmaceutical approaches that aim to reduce complications resulting from the progression of this metabolic pathology.

The Role of High-Resolution Analytical Techniques in the Development of Functional Foods

The approaches based on high-resolution analytical techniques, such as nuclear magnetic resonance or mass spectrometry coupled to chromatographic techniques, have a determining role in several of the stages necessary for the development of functional foods. The analyses of botanical extracts rich in bioactive compounds is one of the fundamental steps in order to identify and quantify their phytochemical composition. However, the compounds characterized in the extracts are not always responsible for the bioactive properties because they generally undergo metabolic reactions before reaching the therapeutic targets. For this reason, analytical techniques are also applied to analyze biological samples to know the bioavailability, pharmacokinetics and/or metabolism of the compounds ingested by animal or human models in nutritional intervention studies. In addition, these studies have also been applied to determine changes of endogenous metabolites caused by prolonged intake of compounds with bioactive potential. This review aims to describe the main types and modes of application of high-resolution analytical techniques in all these steps for functional food development.

Rosemary Tea Consumption Alters Peripheral Anxiety and Depression Biomarkers: A Pilot Study in Limited Healthy Volunteers

Background: Rosmarinus officinalis L.is traditionally used as an infusion in the treatment of several diseases and in particular against neuropsychiatric disorders, such as anxiety and depression. It was established that rosemary extracts show an antidepressant effect on animal models. However, to the best of our knowledge, there is no scientific data that highlights the therapeutic effects of rosemary intake on human mental health.Aim:This study investigated whether rosemary tea consumption affects the plasma levels of anxiety and depression biomarkers in healthy volunteers.Methods:Twenty-two healthy volunteers aged between 20 and 50 years old consumed rosemary tea prepared from 5 g of dried rosemary in 100 mL boiled water once a day for 10 days. Plasma concentrations of Brain-Derived Neurotrophic Factor (BDNF), Interleukine-6 (IL-6), Interleukine-4 (IL-4), Tumor Necrosis Factor- alpha (TNF-α), Interferon-gamma (IFNϒ), and cortisol were measured by enzyme-linked immunosorbent assay using commercial ELISA kits (R&D systems) before rosemary consumption and at the end of the experiment.Results:Rosemary tea consumption significantly increased the concentration of BDNF([BDNF]D0 = 22363.86 ± 12987.66 pg/mL, [BDNF]D10 = 41803.64 ± 28109.19, p = 0.006) and TNF-α([TNF-α] D0 = 39.49 ± 14.44 pg/mL, [TNF-α] D10 = 56.24 ± 39.01, p = 0.016). However, a slight variation that was statistically non-significant in INFϒ, cortisol, IL-4, IL-6 levels and in the ratio IL-4/INFϒ was observed (p > 0.05).Conclusion:Our findings highlight the promising anxiolytic and/or antidepressant effects of rosemary tea consumption in healthy volunteers since it increases the level of the most reliable depression biomarker BDNF. However, more powerful studies with larger sample size, carefully-chosen target population and, an extended intervention period are required.