A Green Extraction Method to Achieve the Highest Yield of Limonin and Hesperidin from Lime Peel Powder (Citrus aurantifolia).

Green extraction is aimed at reducing energy consumption by using renewable plant sources and environmentally friendly bio-solvents. Lime (Citrus aurantifolia) is a rich source of flavonoids (e.g., hesperidin) and limonoids (e.g., limonin). Manufacturing of lime products (e.g., lime juice) yields a considerable amount of lime peel as food waste that should be comprehensively exploited. The aim of this study was to develop a green and simple extraction method to acquire the highest yield of both limonin and hesperidin from the lime peel. The study method included ethanolic-aqueous extraction and variable factors, i.e., ethanol concentrations, pH values of solvent, and extraction temperature. The response surface methodology was used to optimize extraction conditions. The concentrations of limonin and hesperidin were determined by using UHPLC-MS/MS. Results showed that the yields of limonin and hesperidin significantly depended on ethanol concentrations and extraction temperature, while pH value had the least effect. The optimal extraction condition with the highest amounts of limonin and hesperidin was 80% ethanol at pH 7, 50 °C, which yields 2.072 and 3.353 mg/g of limonin and hesperidin, respectively. This study illustrates a green extraction process using food waste, e.g., lime peel, as an energy-saving source and ethanol as a bio-solvent to achieve the highest amount of double bioactive compounds.

Mangiferin and Hesperidin Transdermal Distribution and Permeability through the Skin from Solutions and Honeybush Extracts (Cyclopia sp.)-A Comparison Ex Vivo Study.

Polyphenolic compounds-mangiferin and hesperidin-are, among others, the most important secondary metabolites of African shrub Cyclopia sp. (honeybush). The aim of this study was to compare the percutaneous absorption of mangiferin and hesperidin from solutions (water, ethanol 50%, (v/v)) and extracts obtained from green and fermented honeybush (water, ethanol 50%, (v/v)). Research was performed with the Bronaugh cells, on human dorsal skin. The mangiferin and hesperidin distributions in skin layers (stratum corneum, epidermis, and dermis) and in acceptor fluid (in every 2, 4, 6, and 24 h) were evaluated by HPLC-Photodiode Array Coulometric and Coulometric Electrochemical Array Detection. The transdermal distribution of hesperidin was also demonstrated by fluorescence microscopy. Results indicated that mangiferin and hesperidin were able to cross the stratum corneum and penetrate into the epidermis and dermis. An advantage of hesperidin penetration into the skin from the water over ethanol solution was observed (451.02 ± 14.50 vs. 357.39 ± 4.51 ng/cm2), as well as in the mangiferin study (127.56 ± 9.49 vs. 97.23 ± 2.92 ng/cm2). Furthermore, mangiferin penetration was more evident from nonfermented honeybush ethanol extract (189.85 ± 4.11 ng/cm2) than from solutions. The permeation of mangiferin and hesperidin through the skin to the acceptor fluid was observed regardless of whether the solution or the honeybush extract was applied. The highest ability to permeate the skin was demonstrated for the water solution of hesperidin (250.92 ± 16.01 ng/cm2), while the hesperidin occurring in the extracts permeated in a very low capacity. Mangiferin from nonfermented honeybush ethanol extract had the highest ability to permeate to the acceptor fluid within 24 h (152.36 ± 8.57 ng/cm2).

Kirenol, darutoside and hesperidin contribute to the anti-inflammatory and analgesic activities of Siegesbeckia pubescens makino by inhibiting COX-2 expression and inflammatory cell infiltration.

ETHNOPHARMACOLOGICAL RELEVANCE: The Chinese traditional medicine of Siegesbeckia pubescens Makino (SM), which has the effect of healing rheumatism and promoting joint health, is often used to treat rheumatoid arthritis and ischemic stroke. AIM OF THE STUDY: To clarify the mechanisms underlying the anti-inflammatory and analgesic influence of active components in the ethanol extract of Siegesbeckia pubescens Makino (ESM). MATERIALS AND METHODS: The active ingredients in the ESM were identified practicing high-performance liquid chromatography-diode array detection (HPLC-DAD). Four models including xylene-induced ear oedema, complete Freund's adjuvant (CFA)-induced hind paw oedema, acetic acid-induced pain writhing and lipopolysaccharide (LPS)-induced RAW264.7 cell migration, were used to clarify the anti-inflammatory and analgesic mechanisms of the active ingredients in the ESM. RESULTS: (1) Three active ingredients of kirenol, darutoside and hesperidin were identified in the ESM, with relative proportion of 0.6%, 0.2% and 0.01%, respectively; hesperidin was reported for the first time in the ESM. (2) Both the ESM and its active ingredients could effectively alleviate the degree of swelling of the auricle and toes, increase the threshold of heat pain, decrease the overexpression of inflammatory protein cyclooxygenase-2 (COX-2) in the skin tissue of the tested parts of the toes, and reduce the number of writhes induced by acetic acid in mice. (3) ESM and its active ingredients also dose-dependently inhibited the migration of RAW264.7 cells. CONCLUSIONS: ESM and its active ingredients can effectively attenuate the expression of inflammatory factors induced by chemical inflammation, prevent the infiltration of inflammatory cells, and exert good anti-inflammatory and antinociceptive activities.

Application of accelerated solvent extraction coupled with online two-dimensional countercurrent chromatography for continuous extraction and separation of bioactive compounds from Citrus limon peel.

Drug discovery from complex mixtures, like Chinese herbs, is challenging and extensive false positives make it difficult to obtain compounds with anti-Alzheimer's activity. In this study, a continuous method comprised of accelerated solvent extraction coupled with online two-dimensional countercurrent chromatography was developed for the efficient, scaled-up extraction and separation of six bioactive compounds from Citrus limon peels: neoeriocitrin, isonaringin, naringin, hesperidin, neohesperidin, and limonin. These active compounds were isolated and purified from the raw plant materials by two-dimensional countercurrent chromatography separation via two sets of an n-hexane/n-butanol/methanol/water solvent system: 0.23:1.00:0.25:1.13 and 0.47:1.00:0.38:1.46, v/v/v/v. The compounds were collected in yields of 0.22, 0.25, 0.10, 0.31, 0.29, and 0.28 mg/g, respectively, with purities of 95.79, 96.47, 97.69, 97.22, 98.11, and 98.82%, respectively. Subsequently, a simple and efficient in vitro method was developed for rapidly evaluating the acetylcholinesterase inhibitory activities of six bioactive components. Furthermore, the PC12 cell model and the in vitro metabolism of cytochromes P450 were employed to verify the monomers obtained from the continuous method. The results demonstrated that these six bioactive extracts from the C. limon peels were strong acetylcholinesterase inhibitors.

The Effects of Different Varieties of Aurantii Fructus Immaturus on the Potential Toxicity of Zhi-Zi-Hou-Po Decoction Based on Spectrum-Toxicity Correlation Analysis.

In accordance with the provision in China Pharmacopoeia, Citrus aurantium L. (Sour orange-SZS) and Citrus sinensis Osbeck (Sweet orange-TZS) are all in line with the requirements of Aurantii Fructus Immaturus (ZS). Both kinds of ZS are also marketed in the market. With the frequent occurrence of depression, Zhi-Zi-Hou-Po decoction (ZZHPD) has attracted wide attention. Currently, studies have shown that ZZHPD has a potential toxicity risk, but the effect of two commercial varieties of ZS on ZZHPD has not been reported. In this study, the toxicity differences of ZZHPD prepared by SZS and TZS were revealed through repeated administration experiments in rats. This indicated that different varieties of ZS could affect the toxicity of the prescription. In order to further study the chemical material basis of the toxicity difference, the fingerprints of ZZHPD prepared by different varieties of ZS were established by high-performance liquid chromatography (HPLC). Five different characteristic peaks were screened by non-target chemometrics. They were identified as geniposide, neoeriocitrin, naringin, hesperidin, and neohesperidin using an HPLC-time-of-flight mass spectrometry analyzer (TOF/MS) and an HPLC-triple stage quadrupole mass spectrometry analyzer (QqQ-MS/MS). Combined with a quantitative analysis and previous studies on promoting the intestinal absorption of geniposide, it is speculated that the synergistic effects of the components may be the main reason for the difference of toxicity among the different medicinal materials. This study provides a reference for the clinical, safe use of ZZHPD, and also provides a new perspective for the study of the potential toxic substances of traditional Chinese medicine compound preparations.

Citrus peels waste as a source of value-added compounds: Extraction and quantification of bioactive polyphenols.

A method combining solid-liquid extraction based on ethanolic aqueous solution, cLC-DAD and chemometrics, was performed to extract and quantify polyphenols from citrus peels. LC-MS/MS was also employed for chemical profiling. The effect of extraction variables on the recovery was examined by experimental factorial design. Data were evaluated using multifactorial-ANOVA, response surface analysis and Principal Component Analysis. trans-Ferulic and p-coumaric antioxidants were found in lower quantities (<1.4 mg·g-1) in all peel extracts. Narangin flavonoid was also identified in all samples, while rutin flavonol was determined in the concentration range of 3.3-4.7 mg·g-1. The most abundant polyphenol in the extracts obtained from all evaluated citrus samples was the flavanone hesperidin (280-673 mg·g-1). Furthermore, peel extracts were evaluated in terms of total polyphenol and flavonoid content, total antioxidant activity and DPPH free radical scavenging. The obtained results suggested that evaluated citrus peel by-products could be reused as a source of polyphenols and transformed into value-added products.

Effect of citrus peel extracts on the cellular quiescence of prostate cancer cells.

The re-entry of quiescent cancer cells to the cell cycle plays a key role in cancer recurrence, which can pose a high risk after primary treatment. Citrus peel extracts (CPEs) contain compounds that can potentially impair tumour growth; however the mechanism of action and effects on cell cycle regulation remain unclear. In this study, the capacity of an ethyl acetate : hexane extract (CPE/hexane) and water extract (CPE/water) to modulate the cell cycle re-entry of quiescent (PC-3 and LNCaP) prostate cancer cells was tested in an in vitro culture system. Cell cycle analysis showed that the quiescent PC-3 and LNCaP cancer cells in the presence of CPE/water were impaired in their ability to enter the S phase where only 2-3% reduction of G0/G1 cells was noted compared to 12-18% reduction of control cells. In contrast, the CPE/hexane did not show any cell cycle inhibition activity in both cell lines. A low DNA synthesis rate and weak apoptosis were observed in quiescent cancer cells treated with CPEs. Hesperidin and narirutin, the predominant flavonoids found in citrus fruits, were not responsible for the observed biological activity, implicating alternative bioactive compounds. Notably, citric acid was identified as one of the compounds present in CPEs that acts as a cell cycle re-entry inhibitor. Citric acid exhibited a higher cell toxicity effect on PC-3 prostate cancer cells than non-cancerous RWPE-1 prostate cells, suggesting specific benefits for cancer treatment. In conclusion, CPE containing citric acid together with various bioactive compounds may be used as a chemopreventive agent for post-therapy cancer patients.

Acute and sub-chronic oral toxicity studies of hesperidin isolated from orange peel extract in Sprague Dawley rats.

Citrus sinensis contains glycoside hesperetin-7-rhamnoglucoside (hesperidin) which harbor an array of therapeutic potentials including antioxidant, anticancer, and anti-inflammatory. However, a systematic examination of safety is needed before its utilization. Hence, the present investigation is aimed to evaluate acute and sub-chronic toxicity of hesperidin isolated from the citrus fruit. Hesperidin (73%) was isolated from a methanolic extract of dried peel of the citrus fruit, characterized using FTIR, and standardized by HPLC. Its acute oral toxicity (AOT) and sub-chronic toxicity studies were carried out in Sprague-Dawley rats. Hesperidin (5000 mg/kg) showed 10% mortality in AOT. In sub-chronic toxicity study, hesperidin (250 and 500 mg/kg) did not induce any abnormalities in body weight, food consumption, clinical signs, ophthalmological and neurological observations, urine analysis, hematology, clinical chemistry, organ weights, and gross pathology. However, hesperidin (1000 mg/kg) showed significant (p < 0.05) alterations in body and organ weights, hematology, clinical chemistry, and tissue histopathology. To conclude, hesperidin has median lethal dose (LD50) of 4837.5 mg/kg, and Low Observed Adverse Effect Level (LOAEL) at 1000 mg/kg for both male and female Sprague-Dawley rats. Thus, hesperidin isolated from citrus fruit showed a good safety profile in animal study.

Hesperidin, a major flavonoid in orange juice, might not affect lipid profile and blood pressure: A systematic review and meta-analysis of randomized controlled clinical trials.

Previous studies have led to conflicting results regarding the effect of hesperidin supplementation on cardiometabolic markers. This study aimed to evaluate the efficacy of hesperidin supplementation on lipid profile and blood pressure through a systematic review and meta-analysis of randomized controlled trials (RCTs). PubMed, Web of Science, Scopus, and Google Scholar, as well as the reference lists of the identified relevant RCTs, were searched up to May 2018. Effect sizes were pooled by using the random effects model. Ten RCTs (577 participants) were eligible to be included in the systematic review. The meta-analysis revealed that hesperidin supplementation had no effect on serum total cholesterol (weighted mean difference [WMD] = -1.04 mg/dl; 95% confidence interval [CI]: -5.65, 3.57), low-density lipoprotein cholesterol (WMD = -1.96 mg/dl; 95% CI [-7.56, 3.64]), high-density lipoprotein cholesterol (WMD = 0.16 mg/dl; 95% CI [-1.94, 2.28]), and triglyceride (WMD = 0.69 mg/dl; 95% CI [-5.91, 7.30]), with no significant between-study heterogeneity. Hesperidin supplement also had no effect on systolic (WMD = -0.85 mmHg; 95% CI [-3.07, 1.36]) and diastolic blood pressure (WMD = -0.48 mmHg; 95% CI [-2.39, 1.42]). Hesperidin supplementation might not improve lipid profile and blood pressure. Future well-designed trials are still needed to confirm these results.

Deep eutectic solvent as a green solvent for enhanced extraction of narirutin, naringin, hesperidin and neohesperidin from Aurantii Fructus.

INTRODUCTION: In the present study, a green and efficient extraction method using deep eutectic solvents as extraction solvent was developed for extracting the four major active compounds narirutin, naringin, hesperidin and neohesperidin from Aurantii Fructus. METHODOLOGY: A series of tunable deep eutectic solvents were prepared and investigated by mixing choline chloride or betaine to different hydrogen-bond donors, and betaine/ethanediol was found to be the most suitable extraction solvent. To achieve the best extraction yield, the primary factors affecting the extraction efficiency, such as hydrogen-bond acceptor/hydrogen-bond donor ratio, water content in deep eutectic solvents, extraction temperature, solid/liquid ratio and extraction time, were investigated. RESULTS: The optimal extraction conditions were 40% of water in betaine/ethanediol (1:4) at 60°C for heated extraction of 30 min and solid/liquid ratio 1:100 g/mL. Under the optimum extraction condition, the extraction yields of narirutin, naringin, hesperidin, and neohesperidin were 8.39 ± 0.61, 83.98 ± 1.92, 3.03 ± 0.35 and 35.94 ± 0.63 mg/g, respectively, which were much higher than those of methanol as extraction solvent (5.5 ± 0.48, 64.23 ± 1.51, 2.16 ± 0.15 and 30.14 ± 0.62 mg/g). CONCLUSION: The present results showed that deep eutectic solvents could be promising green and efficient solvents for extraction of the bioactive ingredients from traditional Chinese medicine.

Scrophularia lucida L. as a valuable source of bioactive compounds for pharmaceutical applications: In vitro antioxidant, anti-inflammatory, enzyme inhibitory properties, in silico studies, and HPLC profiles.

The genus Scrophularia has received much interest with regards to its traditional uses against eczema, psoriasis, and mastitis. Yet, the medicinal properties of some species still need to be scientifically validated. The present study was designed to investigate into the biological properties of various solvent extracts (ethyl acetate, methanol, and aqueous) of the roots and aerial parts of Scrophularia lucida based on its antioxidant, anti-inflammatory, and enzyme inhibitory activities together with phytochemical screening. Our results revealed that the solvent extracts differed in their biological effectiveness. The root ethyl acetate extract showed the highest ABTS scavenging, FRAP, CUPRAC, and inhibitory activity against AChE and α-glucosidase. The ethyl acetate extract of the aerial parts displayed the highest BChE and α-amylase inhibition and antioxidant effect in the phosphomolybdenum assay, while the methanol extracts of both parts were the most effective DPPH• scavengers and tyrosinase inhibitors. The methanol extracts of the root and aerial parts also inhibited NO production in lipopolysaccharide (LPS)-stimulated murine leukemic monocyte-macrophage cell (4.99% and 10.77%, respectively), at 31.25 µg/mL concentration. The highest TPC (34.98 mg GAE/g extract) and TFC (48.33 mg RE/g extract) were observed in the ethyl acetate extract of the root and aerial parts, respectively. The most abundant compounds in the root ethyl acetate extract were luteolin (852 µg/g extract), rosmarinic acid (522 µg/g extract), and hesperidin (394 µg/g extract) while kaempferol was most abundant in the ethyl acetate extract of the aerial parts (628 µg/g extract). In silico experiments were conducted on tyrosinase and the higher docking values were observed for rosmarinic acid and hesperidin. The present findings provide base line information which tend to support the potential use of S. lucida in the management of several chronic diseases, including Alzheimer's disease and diabetes mellitus.

Hesperidin Suppresses Renin-Angiotensin System Mediated NOX2 Over-Expression and Sympathoexcitation in 2K-1C Hypertensive Rats.

Hesperidin, a flavonoid derived from citrus fruits, possesses several beneficial effects including anti-oxidation and anti-inflammation. The aim of this study was to investigate the effects of hesperidin on the renin-angiotensin system (RAS) cascade that mediated oxidative stress and sympathoexcitation in two-kidney, one-clipped (2K-1C) hypertensive rats. 2K-1C hypertension was induced in male Sprague-Dawley rats. Hypertensive rats were treated with hesperidin at 20[Formula: see text]mg/kg or 40[Formula: see text]mg/kg or losartan at 10[Formula: see text]mg/kg beginning at three weeks after surgery and then continued for four weeks ([Formula: see text]/group). Hesperidin reduced blood pressure in a dose-dependent manner in hypertensive rats compared to untreated rats ([Formula: see text]). Increased plasma angiotensin converting enzyme (ACE) activity and angiotensin II levels, as well as, upregulated AT1 receptor protein expression in aortic tissues were attenuated in hypertensive rats treated with hesperidin. Hesperidin suppressed oxidative stress markers and NADPH oxidase over-expression, and restored plasma nitric oxide metabolites in 2K-1C rats. This was associated with improvement of the vascular response to acetylcholine in isolated mesenteric vascular beds and aortic rings from 2K-1C rats treated with hesperidin ([Formula: see text]). Enhancement of nerve-mediated vasoconstriction related to high plasma noradrenaline in the 2K-1C group was alleviated by hesperidin treatment ([Formula: see text]). Furthermore, losartan exhibited antihypertensive effects by suppressing the RAS cascade and oxidative stress and improved vascular dysfunction observed in 2K-1C rats ([Formula: see text]). Based on these results, it can be presumed that hesperidin is an antihypertensive agent. Its antihypertensive action might be associated with reducing RAS cascade-induced NOX2 over-expression and sympathoexcitation in 2K-1C hypertensive rats.

Enhanced anti-oxidative effect of fermented Korean mistletoe is originated from an increase in the contents of caffeic acid and lyoniresinol.

Viscum album var. coloratum (Korean mistletoe; KM) is an herbal medicine that is used worldwide for the treatment of various immunological disorders and cancers. KM extract showed enhanced anti-oxidative effects in 2,2-diphenyl-1-picrylhydrazyl, Trolox equivalent antioxidant capacity, and 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate acetyl ester assays after being fermented with a crude enzyme extract from a soybean paste fungus, Aspergillus kawachii. High-performance liquid chromatography analysis showed four increased peaks in enzyme treated KM. The increased peaks were isolated and identified as caffeic acid (1), hesperetin (2), syringaldehyde (3), and lyoniresinol (4). Among the four compounds, only 1 and 4 showed strong anti-oxidative activity. Therefore, the fermentation increased the contents of 1 and 4, which consequently increased the anti-oxidative activity of KM.

Phytochemical analysis, antimicrobial, antioxidant activities and total phenols of Ferulago carduchorum in two vegetative stages (flower and fruit).

Ferulago carduchorum (Apiaceae family) is an endemic plant of Iran. The crude extract and four fractions of aerial parts of F. carduchorum in two vegetative stages (flower and fruit) were studied for their total phenolic contents, antimicrobial and antioxidant activities using folin-ciocalteu assay, micro dilution method and DPPH assay, respectively. The results indicated that the best antioxidant activity was determined in flower crude extract (IC50=0.44 mg/mL). The flower ethyl acetate fraction (FLE) showed better antimicrobial and antifungal activities than other fractions. So, FLE was selected for phytochemical investigations, resulting in isolation of a flavonoid (hesperetin). Hesperetin showed antimicrobial activity. The results showed that the antimicrobial and antioxidant effects during the flowering are obviously more than the fruit season.

Chemical Evidence for Potent Xanthine Oxidase Inhibitory Activity of Ethyl Acetate Extract of Citrus aurantium L. Dried Immature Fruits.

Xanthine oxidase is a key enzyme which can catalyze hypoxanthine and xanthine to uric acid causing hyperuricemia in humans. Xanthine oxidase inhibitory activities of 24 organic extracts of four species belonging to Citrus genus of the family Rutaceae were assayed in vitro. Since the ethyl acetate extract of C. aurantium dried immature fruits showed the highest xanthine oxidase inhibitory activity, chemical evidence for the potent inhibitory activity was clarified on the basis of structure identification of the active constituents. Five flavanones and two polymethoxyflavones were isolated and evaluated for inhibitory activity against xanthine oxidase in vitro. Of the compounds, hesperetin showed more potent inhibitory activity with an IC50 value of 16.48 µM. For the first time, this study provides a rational basis for the use of C. aurantium dried immature fruits against hyperuricemia.

Application of ionic liquids in vacuum microwave-assisted extraction followed by macroporous resin isolation of three flavonoids rutin, hyperoside and hesperidin from Sorbus tianschanica leaves.

Rutin, hyperoside and hesperidin were effectively extracted from Sorbus tianschanica leaves by an ionic liquid vacuum microwave-assisted method. A series of ionic liquids with various anions and alkyl chain length of the cations were studied and the extraction was performed in [C6mim][BF4] aqueous solution. After optimization by a factorial design and response surface methodology, total extraction yield of 2.37mg/g with an error of 0.12mg/g (0.71±0.04mg/g, 1.18±0.06mg/g and 0.48±0.02 for rutin, hyperoside and hesperidin, respectively) was achieved under -0.08MPa for vacuum, 19min and 420W for microwave irradiation time and power, and 15mL/g for liquid-solid ratio. The proposed method here is more efficient and needs a shorter extraction time for rutin, hyperoside and hesperidin from S. tianschanica leaves than reference extraction techniques. In stability studies performed with standard rutin, hyperoside and hesperidin, the target analytes were stable under the optimum conditions. The proposed method had a high reproducibility and precision. In addition, separation of rutin, hyperoside and hesperidin from [C6mim][BF4] extraction solution was completed effectively by AB-8 macroporous resin adsorption and desorption process. Ionic liquid vacuum microwave-assisted extraction is a simple, rapid and efficient sample extraction technique.

Isolation and identification of chemical constituents from Origanum majorana and investigation of antiproliferative and antioxidant activities.

BACKGROUND: Origanum majorana L., belonging to the Lamiaceae family, has great potential and has been used as a folk medicine against asthma, indigestion, headache and rheumatism; in addition, the essential oils of this plant have been used widely in the food industry. Plant materials have been harvested from the Medicinal and Aromatic Plant Field of Gaziosmanpasa University. Air-dried plant materials were boiled in water, filtered, and the solvent part subsequently extracted with hexane and ethyl acetate. The chromatographic method was applied to the ethyl acetate extract to isolate bioactive secondary metabolites, the structures of which were elucidated by spectroscopic techniques: basically one-dimensional and two-dimensional nuclear magnetic resonance and quadrupole time-of-flight liquid chromatography. Antiproliferative and antioxidant activities of isolated secondary metabolites were determined. RESULTS: 5,6,3'-Trihydroxy-7,8,4'-trimethoxyflavone, hesperetin, hydroquinone, arbutin and rosmarinic acid were isolated from the water-soluble ethyl acetate extract of aerial parts of O. majorana. Antioxidant activities of isolated compounds and water-soluble ethyl acetate extract were investigated using assays of DPPH(•), ABTS(•+), reducing power and total phenolic content. Antiproliferative activities of the isolated compounds and plant extracts were investigated against C6 and HeLa cell lines using BrdU cell proliferation enzyme-linked immunosorbent assay and xCELLigence assay, respectively. Both hesperetin and hydroquinone were determined to have stronger antiproliferative activities against C6 and HeLa cells than the other isolated compounds and 5-fluorouracil. CONCLUSION: The results showed that the extract and isolated compounds exhibited significant antioxidant activities. Hence this plant has the potential to be a natural antioxidant in the food industry and an anticancer drug.

Comparison of Ensemble Strategies in Online NIR for Monitoring the Extraction Process of Pericarpium Citri Reticulatae Based on Different Variable Selections.

Different ensemble strategies were compared in online near-infrared models for monitoring active pharmaceutical ingredients of Traditional Chinese Medicine. Bagging partial least square regression and boosting partial least square regression were adopted to near-infrared models, to determine hesperidin and nobiletin content during the extraction process of Pericarpium Citri Reticulatae in a pilot scale system. Different pretreatment methods were investigated, including Savitzky-Golay smoothing, derivatives, multiplicative scatter correction, standard normal variate, normalize, and combinations of them. Two different variable selection methods, including synergy interval partial least squares and backward interval partial least squares algorithms, were performed. Based on the result of the synergy interval partial least squares algorithm, bagging partial least square regression and boosting partial least square regression were adopted into the quantitative analysis. The results demonstrated that the established approach could be applied for rapid determination and real-time monitoring of hesperidin and nobiletin in Pericarpium Citri Reticulatae (Citrus reticulata) during the extraction process. Comparing the results, the boosting partial least square regression provided a slightly better accuracy than the bagging partial least square regression. Finally, this paper provides a promising ensemble strategy on online near-infrared models in Chinese medicine.

In situ detection and identification of hesperidin crystals in satsuma mandarin (Citrus unshiu) peel cells.

INTRODUCTION: Hesperidin, a flavonoid known to have important pharmacological effects, accumulates particularly in the peels of satsuma mandarin (Citrus unshiu). Although histochemical studies have suggested that hesperidin forms crystals in some tissues of the Rutaceae and Umbelliferae, there has been no rigorous in situ detection or identification of hesperidin crystals in C. unshiu. OBJECTIVE: To characterise the chemical component of the crystals found in C. unshiu peels using Raman microscopy. METHODS: Sections of C. unshiu peels were made. The distribution and morphology of crystals in the sections were analysed microscopically. Raman microscopy was used to detect hesperidin in the sections directly. RESULTS: The crystals were more abundant in immature peel and were observed particularly in areas surrounding vascular bundles, around the border between the flavedo and albedo layers and just below the epidermal cells. In the morphological analysis by scanning electron microscopy, needle-shaped crystals aggregated and formed clusters of spherical crystals. Spectra obtained by Raman microscopy of the crystals in the peel sections were consistent with those of the hesperidin standard. CONCLUSION: This study showed the detailed distribution of crystals in C. unshiu peels and their main component was identified using Raman microscopy to be hesperidin for the first time.

Development of new reference material neohesperidin for quality control of dietary supplements.

BACKGROUND: Neohesperidin is an important natural flavanone glycoside distributed in several citrus species. This compound is widely used as a raw material for food additives in the food industry. The request for certified reference materials (CRMs) in dietary supplements was stipulated by the National Administrative Committee for CRMs and was underpinned by the need to improve the accuracy and comparability of measurement data and to establish metrological traceability of analytical results. RESULTS: This paper reports the sample preparation methodology, homogeneity and stability studies, value assignment and uncertainty estimation of a new certified reference material of neohesperidin (GBW09522). Differential scanning calorimetry, coulometric titration and mass balance methods proved to be sufficiently reliable and accurate for certification purposes. The certified value of neohesperidin CRM is 994 g kg(-1) with an expanded uncertainty of 4 g kg(-1) (k = 2). The reference material described above was homogeneous and stable for 12 months at a storage temperature of 25 °C. CONCLUSION: The new CRM of neohesperidin can be used to validate analytical methods and improve the accuracy of measurement data as well as quality control of neohesperidin-related dietary supplements, foods, traditional herbs and pharmaceutical formulations.