Identification and Extraction Optimization of Active Constituents in Citrus junos Seib ex TANAKA Peel and Its Biological Evaluation

Recent Advances in the Management of Rosacea through Natural Compounds

Rosacea is a chronic skin disorder that affects more than 5% of the world's population, with the number increasing every year. Moreover, studies show that one-third of those suffering from rosacea report a degree of depression and are less compliant with treatment. Despite being the subject of prolonged studies, the pathogenesis of rosacea remains controversial and elusive. Since most medications used for the management of this pathology have side effects or simply do not yield the necessary results, many patients lose trust in the treatment and drop it altogether. Thus, dermato-cosmetic products with natural ingredients are gaining more and more notoriety in front of synthetic ones, due to the multiple benefits and the reduced number and intensity of side effects. This review is a comprehensive up-to-date report of studies that managed to prove the beneficial effects of different botanicals that may be useful in the short and long-term management of rosacea-affected skin. Based on recent preclinical and clinical studies, this review describes the mechanisms of action of a large array of phytochemicals responsible for alleviating the clinical symptomatology of the disease. This is useful in further aiding and better comprehending the way plant-based products may help in managing this complex condition, paving the way for research in this area of study.

Process Optimization Based on Biological Effects and Biomarker Contents of Camellia japonica L. for the Development of Anti-Hyperuricemic and Anti-Wrinkle Source

The purpose of this study was to simultaneously develop anti-hyperuricemic and anti-wrinkle source using Camellia japonica leaf (CJ). CJ extract was prepared. Its contents of biomarkers and biological activities were then analyzed. First, we investigated the extraction efficiency. The extraction rate was 10% or less with hot water or 80% ethanol. HPLC analysis revealed that CJ extract contained rutin, hyperoside, isoquercitrin, chlorogenic acid (CGA), gallocatechin gallate (GCG), and phillygenin. As a result of measuring contents of biomarkers in the extract, CGA was detected in 20, 40, and 60% ethanol extracts. GCG showed the highest content in the hot water extract. Hyperoside and isoquercitrin showed the highest contents in the 80% ethanol extract. Philligenin showed an even content of 0.1% or more in all samples except for 40% ethanol extract. Rutin showed the highest content in 80% ethanol extract. Elastase inhibitory abilities of six extracts and PPRM were investigated at a concentration of 0.5 mg/mL. Results revealed that PPRM and 80% ethanol extract showed about 80% and 62% inhibition, respectively. As a result of comparing elastase inhibitory activities of biomarkers, hyperoside, isoquercitrin, and philligenin showed higher activities. Among six extracts, the extract that could be used as an anti-hyperuricemic source was 80% ethanol extract. When xanthine oxidase (XO) inhibitory activities of biomarkers were evaluated, rutin and hyperoside showed excellent activities. In particular, when XO activity was measured by mixing rutin and hyperoside with 80% ethanol extract, the same efficacy as 80% ethanol extract was obtained. It was predicted that 80% ethanol extract could be used simultaneously as an anti-hyperuricemic and anti-wrinkle source. Further studies are needed to determine anti-hyperuricemic activities of rutin and hyeproside in vivo.

Ameliorative Effect of Citrus junos Tanaka Waste (By-Product) Water Extract on Particulate Matter 10-Induced Lung Damage

Citrus junos Tanaka (CJ)-related products are well-accepted by consumers worldwide; thus, they generate huge amounts of waste (peel, pulp, and seed) through CJ processing. Although some CJ by-products (CJBs) are recycled, their use is limited owing to the limited understanding of their nutritional and economic value. The exposure to particulate matter (PM) increases the risk of respiratory diseases. In this study, we investigated the ameliorative effects of CJB extracts (100, 200 mg/kg/day, 7 days) on PM10-induced (10 mg/kg, intranasal, 6 h) lung damage in BALB/c mice. Cell type-specific signaling pathways are examined using the A549 (PM10, 200 μg/mL, 6 h) and RAW264.7 (LPS, 100 ng/mL, 6 h) cell lines. The CJB extracts significantly attenuated PM10-induced pulmonary damage and inflammatory cell infiltration in a mouse model. The essential protein markers in inflammatory signaling pathways, such as AKT, ERK, JNK, and NF-κB for PM10-induced phosphorylation, were dramatically reduced by CJB extract treatment in both the mouse and cell models. Furthermore, the CJB extracts reduced the production of reactive oxygen species and nitric oxide in a dose-dependent manner in the cells. Comprehensively, the CJB extracts were effective in reducing PM10-induced lung injuries by suppressing pulmonary inflammation, potentially due to their anti-inflammatory and antioxidant properties.

A Narrative Review of the Effects of Citrus Peels and Extracts on Human Brain Health and Metabolism

As life expectancy increases, age-associated diseases such as Alzheimer's disease (AD) become a major health problem. The onset of AD involves neurological dysfunction due to amyloid-β accumulation, tau hyperphosphorylation, oxidative stress, and neuroinflammation in the brain. In addition, lifestyle-related diseases-such as dyslipidemia, diabetes, obesity, and vascular dysfunction-increase the risk of developing dementia. The world population ages, prompting the development of new strategies to maintain brain health and prevent the onset of dementia in older and preclinical patients. Citrus fruits are abundant polymethoxylated flavone and flavanone sources. Preclinical studies reported that these compounds have neuroprotective effects in models of dementia such as AD. Interestingly, clinical and epidemiological studies appear to support preclinical evidence and show improved cognitive function and reduced associated disease risk in healthy individuals and/or patients. This review summarizes the recent evidence of the beneficial effects of citrus peels and extracts on human cognition and related functions.

Citrus junos Tanaka Peel Extract and Its Bioactive Naringin Reduce Fine Dust-Induced Respiratory Injury Markers in BALB/c Male Mice

Particulate matter (PM) 10 refers to fine dust with a diameter of less than 10 µm and induces apoptosis and inflammatory responses through oxidative stress. Citrus junos Tanaka is a citrus fruit and contains bioactive flavonoids including naringin. In the present study, we aimed to identify the preventive effect of Citrus junos Tanaka peel extract (CPE) against PM10-induced lung injury. As a proof of concept, NCI-H460 cells were treated with CPE (800 μg/mL, 12 h) in conjunction with PM10 to examine intracellular antioxidative capacity in the pulmonary system. In an in vivo model, male BALB/c mice (n = 8/group) were randomly assigned into five groups: NEG (saline-treated), POS (PM10 only), NAR (PM10 + naringin, 100 mg/kg), CPL (PM10 + CPE low, 100 mg/kg), and CPH (PM10 + CPE high, 400 mg/kg). Intervention groups received dietary supplementations for 7 days followed by PM10 exposure (100 mg/kg, intranasal instillation). Compared to the NEG, the CPE decreased to 22% of the ROS generation and significantly increased cell viability in vitro. The histological assessments confirmed that pulmonary damages were alleviated in the PM10 + CPL group compared to the POS. Pro-inflammatory cytokines and NF-κB/apoptosis signaling-related markers were decreased in the PM10 + CPL group compared to the POS. These results indicated that CPE showed promising efficacy in preventing pulmonary injuries in vivo. Such protection can be explained by the anti-oxidative capacity of CPE, likely due to its bioactives, including naringin (7.74 mg/g CPE). Follow-up human intervention, as well as population-level studies, will further shed light on the preventive efficacy of CPE against pulmonary damage in humans.

Chemical Variation of Chenpi (Citrus Peels) and Corresponding Correlated Bioactive Compounds by LC-MS Metabolomics and Multibioassay Analysis

The peel of Citrus reticulata “Chachi” (CP) possesses various health-promoting benefits and is not only one of the most famous Chinese herbal medicine, but also an ingredient in fermented foods. In the present study, the effects of storage years (1-, 3-, 4-, 5-, 6-, and 11-years) on the chemical profiling and potential bioactive compounds of CP were compared by metabolomics and in vitro bioactivity analysis. With the increase of storage time, the content of hesperidin significantly decreased, but nobiletin, 3,5,6,7,8,3′,4′-heptamethoxyflavone, and tangeretin were increased. Meanwhile, the antioxidant activity of CP was enhanced. Phenolic acids, flavonol glycosides, fatty acids, and alkyl glycosides were marker compounds that were responsible for distinguishing the storage time of CP. Correlation analysis suggested that some polyphenols including quercetin-glucoside, quinic acid, trihydroxydimethoxyflavone, and rutin were potential antioxidant compounds in CP. The dichloromethane and n-butanol fractions showed the better antioxidant capacity and inhibitory effects on glucose-hydrolysis enzymes. They mainly contained ferulic acid, nobiletin, 3,5,6,7,8,3′,4′-heptamethoxyflavone, kaempferol, and hesperidin.

A Narrative Review of Human Clinical Trials on the Impact of Phenolic-Rich Plant Extracts on Prediabetes and Its Subgroups

Phenolic-rich plant extracts have been demonstrated to improve glycemic control in individuals with prediabetes. However, there is increasing evidence that people with prediabetes are not a homogeneous group but exhibit different glycemic profiles leading to the existence of prediabetes subgroups. Prediabetes subgroups have been identified as: isolated impaired fasting glucose (IFG), isolated impaired glucose tolerance (IGT), and combined impaired fasting glucose and glucose intolerance (IFG/IGT). The present review investigates human clinical trials examining the hypoglycemic potential of phenolic-rich plant extracts in prediabetes and prediabetes subgroups. Artemisia princeps Pampanini, soy (Glycine max (L.) Merrill) leaf and Citrus junos Tanaka peel have been demonstrated to improve fasting glycemia and thus may be more useful for individuals with IFG with increasing hepatic insulin resistance. In contrast, white mulberry (Morus alba Linn.) leaf, persimmon (Diospyros kaki) leaf and Acacia. Mearnsii bark were shown to improve postprandial glycemia and hence may be preferably beneficial for individuals with IGT with increasing muscle insulin resistance. Elaeis guineensis leaf was observed to improve both fasting and postprandial glycemic measures depending on the dose. Current evidence remains scarce regarding the impact of the plant extracts on glycemic control in prediabetes subgroups and therefore warrants further study.

Pressurized Extraction as an Opportunity to Recover Antioxidants from Orange Peels: Heat treatment and Nanoemulsion Design for Modulating Oxidative Stress

Orange peel by-products generated in the food industry are an important source of value-added compounds that can be potentially reused. In the current research, the effect of oven-drying (50–70 °C) and freeze-drying on the bioactive compounds and antioxidant potential from Navelina, Salustriana, and Sanguina peel waste was investigated using pressurized extraction (ASE). Sixty volatile components were identified by ASE-GC-MS. The levels of terpene derivatives (sesquitenenes, alcohols, aldehydes, hydrocarbons, and esters) remained practically unaffected among fresh and freeze-dried orange peels, whereas drying at 70 °C caused significative decreases in Navelina, Salustriana, and Sanguina peels. Hesperidin and narirutin were the main flavonoids quantified by HPLC-MS. Freeze-dried Sanguina peels showed the highest levels of total-polyphenols (113.3 mg GAE·g⁻¹), total flavonoids (39.0 mg QE·g⁻¹), outstanding values of hesperedin (187.6 µg·g⁻¹), phenol acids (16.54 mg·g⁻¹ DW), and the greatest antioxidant values (DPPH•, FRAP, and ABTS^•+ assays) in comparison with oven-dried samples and the other varieties. Nanotechnology approaches allowed the formulation of antioxidant-loaded nanoemulsions, stabilized with lecithin, starting from orange peel extracts. Those provided 70–80% of protection against oxidative UV-radiation, also decreasing the ROS levels into the Caco-2 cells. Overall, pressurized extracts from freeze-drying orange peel can be considered a good source of natural antioxidants that could be exploited in food applications for the development of new products of commercial interest.

Polyphenol Profile and Antimicrobial and Cytotoxic Activities of Natural Mentha × piperita and Mentha longifolia Populations in Northern Saudi Arabia

New sources of polyphenols with anticancer, antioxidant, and antimicrobial properties in arid environments are critical for the development of alternative medicines and natural remedies. This study explored the polyphenol profiles and biological activities of methanolic leaf extracts from natural Mentha × piperita and Mentha longifolia populations in northern Saudi Arabia. Chromatographic analyses identified several polyphenols in M. × piperita including phenolic acids: rosmarinic acid (1547.6 mg/100 g DW (dry weight)), cryptochlorogenic acid (91.7 mg/100 g DW), and chlorogenic acid (69.4 mg/100 g DW), as well as flavonoids: naringin (328.8 mg/100 g DW) and cynaroside (162.8 mg/100 g DW). The major polyphenols in M. longifolia were: rosmarinic acid (781.6 mg/100 g DW), cryptochlorogenic acid (191.1 mg/100 g DW), p-coumaric acid (113.0 mg/100 g DW), m-coumaric acid (112.2 mg/100 g DW), and chlorogenic acid (63.8 mg/100 g DW). M. × piperita and M. longifolia leaf extracts had high antioxidant activities due to the major polyphenols (cynaroside, rosmarinic and cryptochlorogenic acids). M. × piperita had higher activities against different cancer cells than M. longifolia. Naringin, cryptochlorogenic acid, and rosmarinic acid had the highest activities against cancer cells. The leaf extracts had antibacterial effects against most bacteria species (Pseudomonas aeruginosa was most sensitive), which was attributed to the polyphenols. Antifungal activities were similarly broad (Aspergillus flavus was most sensitive) and attributed to naringin, cryptochlorogenic acid, and caffeic acid. Populations of M. × piperita and M. longifolia in Northern Riyadh may be a valuable source of natural biologically active compounds.

A Simple HPLC Method for the Quantitative Determination of Silybin in Rat Plasma: Application to a Comparative Pharmacokinetic Study on Commercial Silymarin Products

Silybin (SBN) is a major active constituent of silymarin, a mixture of flavonoids found in fruits and seeds of milk thistle. The aim of this study was to describe a simple bioanalytical method for quantifying SBN in rat plasma. A simple protein deproteinization procedure with acetonitrile (ACN) was employed for plasma sample preparation. A reversed column and gradient elution of a mobile phase (mixture of phosphate buffer (pH 5.0) and ACN) were used for chromatographic separation. The selectivity, linearity (50–5000 ng/mL), precision, accuracy, recovery, matrix effect, and stability for this method were validated as per the current Food and Drug Administration (FDA) guidelines. Our method for SBN was applied to a comparative pharmacokinetic study on four different commercial silymarin products. This in vivo rat study demonstrated that product #4 significantly enhanced the relative oral bioavailability of SBN, as compared to product #1–3. Therefore, the bioanalytical method proposed herein could serve as a promising alternative for preclinical pharmacokinetic studies on silymarin products and, by extension, clinical use after partial modification and validation.