Extraction of potential bioactive compounds from industrial Tahiti lime (Citrus latifólia Tan.) by-product using pressurized liquids and ultrasound-assisted extraction.

This work evaluated two emerging techniques in extracting phenolic compounds from Tahiti lime pomace - pressurized liquid extraction (PLE) and ultrasound-assisted extraction (UAE). PLE was performed at different temperatures (60 - 110 °C) and times (5 - 40 min), and UAE was carried out varying ultrasound power (160 - 792 W), time (2 - 10 min), and solvent to feed mass ratio (20 - 40 kg solvent/kg dried pomace). Both used ethanol and water (3:1, wt.) as the solvent. The effects of these variables were evaluated on global extraction yield, polyphenols, hesperidin, narirutin yields, and antioxidant capacity. PLE was strongly affected by temperature and extraction time, and the highest temperature (110 °C) provided the best results for global yield, total phenolic, and ORAC, except for hesperidin and narirutin, which were not significative affected by temperature. UAE revealed a weak dependency on power, S/F, and time; however, the lowest power level significantly increased the yields compared to no power application. Thus, P = 480 W, t = 6 min, and S/F = 30 was chosen as the best condition in the UAE in terms of overall extraction yield, total phenolics, specific phenolics, antioxidant capacities, and solvent and energy expenditures. UAE mechanisms were investigated by comparing with heated and stirred maceration, and scanning electron microscopy suggested that total phenolic yield was influenced by mechanisms that only ultrasound can provide. Micrographics confirmed the cavitation effect on Tahiti lime pomace particles' surface. To sum up, PLE resulted in the highest yields and antioxidant capacity, followed by UAE.

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).

New Sustainable Process for Hesperidin Isolation and Anti-Ageing Effects of Hesperidin Nanocrystals.

Hesperidin, a secondary orange (Citrus sinensis) metabolite, was extracted from orange bagasse. No organic solvents or additional energy consumption were used in the clean and sustainable process. Hesperidin purity was approximately 98% and had a yield of 1%. Hesperidin is a known supplement due to antioxidant, chelating, and anti-ageing properties. Herein, hesperidin application to eliminate dark eye circles, which are sensitive and thin skin regions, was studied. In addition, the proposed method for its aqueous extraction was especially important for human consumption. Further, the most effective methods for hesperidin nanonization were explored, after which the nanoemulsions were incorporated into a cream formulation that was formulated for a tropical climate. Silky cream formulations (oil in water) were tested in vitro on artificial 3D skin from cultured cells extracted from skin residues after plastic surgery. The proposed in vitro assay avoided tests of the different formulations in human volunteers and animals. It was shown that one of the nanonized hesperidin formulations was the most skin-friendly and might be used in cosmetics.

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.

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.

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.

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.

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.

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.

Simultaneous extraction and biotransformation process to obtain high bioactivity phenolic compounds from Brazilian citrus residues.

Recent studies have pointed to a reduction in the incidence of some cancers, diabetes, and neuro-degenerative diseases as a result of human health benefits from flavanones. Currently, flavanones are obtained by chemical synthesis or extraction from plants, and these processes are only produced in the glycosylated form. An interesting environmentally friendly alternative that deserves attention regarding phenolic compound production is the simultaneous extraction and biotransformation of these molecules. Orange juice consumption has become a worldwide dietary habit and Brazil is the largest producer of orange juice in the world. Approximately half of the citrus fruit is discarded after the juice is processed, thus generating large amounts of residues (peel and pectinolytic material). Hence, finding an environmentally clean technique to extract natural products and bioactive compounds from different plant materials has presented a challenging task over the last decades. The aim of this study was to obtain phenolics from Brazilian citrus residues with high bioactivity, using simultaneous extraction (cellulase and pectinase) and biotransformation (tannase) by enzymatic process. The highest hesperetin, naringenin and ellagic acid production in the experiment were 120, 80, and 11,250 µg g(-1), respectively, at 5.0 U mL(-1) of cellulase and 7.0 U mL(-1) of tannase at 40°C and 200 rpm. Also, the development of this process generated an increase of 77% in the total antioxidant capacity. These results suggest that the bioprocess obtained innovative results where the simultaneous enzymatic and biotransformatic extracted flavanones from agro-industrial residues was achieved without the use of organic solvents. The methodology can therefore be considered a green technology.

Molecular mechanisms behind the biological effects of hesperidin and hesperetin for the prevention of cancer and cardiovascular diseases.

Hesperidin (Hsd) and its aglycone, hesperetin (Hst), are two flavonoids from citrus species that have various biological properties, particularly those for the prevention of cancer and cardiovascular diseases. Studies have shown both anti-cancer and cancer chemopreventive effects for Hsd and Hst. Cancer chemopreventive properties of Hsd and Hst are mainly associated with their antioxidant, radical scavenging and anti-inflammatory activities. In addition, Hsd and Hst interfere at different stages of cancer. Unlike conventional anti-cancer drugs, Hsd and Hst inhibit tumor growth by targeting multiple cellular protein targets at the same time, including caspases, Bcl-2 (B-cell lymphoma 2) and Bax (Bcl-2 associated X protein) for the induction of apoptosis, and COX-2 (cyclooxygenase-2), MMP-2 (matrix metalloproteinase-2) and MMP-9 for the inhibition of angiogenesis and metastasis. The results of the recent basic and clinical studies revealed the beneficial effects for Hst, Hsd and their derivatives in the treatment of heart failure and cardiac remodeling, myocardial ischemia and infarction, and hypertension. In addition, the valuable effects of Hst and Hsd in the treatment of diabetes and dyslipidemia with their anti-platelet and anticoagulant effects make them good candidates in the treatment of various cardiovascular diseases. In this review, new findings regarding the molecular targets of Hsd and Hst, animal studies and clinical trials are discussed.

Bioassay guided fractionation and identification of active anti-inflammatory constituent from Delonix elata flowers using RAW 264.7 cells.

CONTEXT: Delonix elata (L.) Gamble (Fabaceae) has been used in the Indian traditional medicine system to treat rheumatism and inflammation. AIM: To assess the anti-inflammatory effect of Delonix elata flowers and to isolate the active principle. MATERIALS AND METHODS: The prompt anti-inflammatory constituent was isolated from Delonix elata flower extracts using bioassay guided fractionation in liposaccharide (LPS) stimulated RAW 264.7 macrophage cell line. The anti-inflammatory activity of extracts/fractions/sub-fractions/compounds (10, 25, and 50 µg/ml) was evaluated by estimating the levels of nitric oxide (NO), TNF-α, and IL-1ß after 24 h of LPS induction (1 µg/ml). The isolated active compound was subjected to NMR, IR, and UV analyses for structure determination. RESULTS: In an attempt to search for anti-inflammatory constituents, the active pure principle was isolated and crystallized as a white compound from Delonix elata flowers methanol extract. This active compound (50 µg/ml) decreased the release of inflammatory mediators levels such as NO (0.263 ± 0.03 µM), TNFα (160.20 ± 17.57 pg/ml), and IL-1ß (285.79 ± 15.16 pg/ml) significantly (p < 0.05); when compared to the levels of NO (0.774 ± 0.08 µM), TNFα (501.71 ± 25.14 pg/ml), and IL-1ß (712.68 ± 52.25 pg/ml) from LPS-stimulated macrophage cells. The active compound was confirmed as hesperidin with NMR, IR, and UV spectroscopy data. This is the first report of this compound from Delonix elata flowers. CONCLUSION: The findings of the study support the traditional use of Delonix elata flowers to treat inflammation.

Effect of hesperidin and neohesperidin from bittersweet orange (Citrus aurantium var. bigaradia) peel on indomethacin-induced peptic ulcers in rats.

Hesperidin and neohesperidin are the major flavanones isolated from bittersweet orange. It was recently reported that they have potent anti-inflammatory effects in various inflammatory models. In the present study, the effects of hesperidin and neohesperidin on indomethacin-induced ulcers in rats and the underlying mechanisms were investigated. Gastric ulcers were induced in rats with a single dose of indomethacin. The effects of pretreatment with hesperidin and neohesperidin were assessed in comparison with omeprazole as reference standard. Ulcer index, gene expression of gastric cyclooxygenase-2 (COX-2), tumor necrosis factor alpha (TNF-α), lipid peroxidation product, malondialdhyde (MDA), and reduced glutathione (GSH) content in stomach were measured. Furthermore, gross and histopathological examination was performed. Our results indicated that both hesperidin and neohesperidin significantly aggravated gastric damage caused by indomethacin administration as evidenced by increased ulcer index and histopathological changes of stomach.

UPLC-MS-ELSD-PDA as a powerful dereplication tool to facilitate compound identification from small-molecule natural product libraries.

The generation of natural product libraries containing column fractions, each with only a few small molecules, using a high-throughput, automated fractionation system, has made it possible to implement an improved dereplication strategy for selection and prioritization of leads in a natural product discovery program. Analysis of databased UPLC-MS-ELSD-PDA information of three leads from a biological screen employing the ependymoma cell line EphB2-EPD generated details on the possible structures of active compounds present. The procedure allows the rapid identification of known compounds and guides the isolation of unknown compounds of interest. Three previously known flavanone-type compounds, homoeriodictyol (1), hesperetin (2), and sterubin (3), were identified in a selected fraction derived from the leaves of Eriodictyon angustifolium. The lignan compound deoxypodophyllotoxin (8) was confirmed to be an active constituent in two lead fractions derived from the bark and leaves of Thuja occidentalis. In addition, two new but inactive labdane-type diterpenoids with an uncommon triol side chain were also identified as coexisting with deoxypodophyllotoxin in a lead fraction from the bark of T. occidentalis. Both diterpenoids were isolated in acetylated form, and their structures were determined as 14S,15-diacetoxy-13R-hydroxylabd-8(17)-en-19-oic acid (9) and 14R,15-diacetoxy-13S-hydroxylabd-8(17)-en-19-oic acid (10), respectively, by spectroscopic data interpretation and X-ray crystallography. This work demonstrates that a UPLC-MS-ELSD-PDA database produced during fractionation may be used as a powerful dereplication tool to facilitate compound identification from chromatographically tractable small-molecule natural product libraries.

Isolation of xanthone and benzophenone derivatives from Cyclopia genistoides (L.) Vent. (honeybush) and their pro-apoptotic activity on synoviocytes from patients with rheumatoid arthritis.

A fast and efficient method for the isolation of the C-glucosidated xanthones mangiferin and isomangiferin from the South-African plant Cyclopia genistoides was developed for the first time. The procedure involved extraction, liquid-liquid partitioning with ethyl acetate and subsequent precipitation of mangiferin and isomangiferin from methanol and acetonitrile-water fractions, respectively. Additionally, two benzophenone derivatives: 3-C-ß-glucosides of maclurin and iriflophenone, were isolated from C. genistoides extracts using semi-preparative HPLC. Apart from the above, the isolation procedure also yielded hesperidin and small amounts of luteolin. The structures of the compounds were determined by 1D and 2D NMR experiments and/or LC-DAD-ESI-MS. The selected Cyclopia constituents were screened for pro-apoptotic activity on TNF-α-stimulated synovial cells isolated from rheumatoid arthritis patients. The strongest effect, measured as percent of apoptotic cells, was recorded for isomangiferin (75%), followed by iriflophenone 3-C-ß-glucoside (71%), hesperidin (67%) and mangiferin (65%). The results are encouraging for further studies on the use of the above compounds in the treatment of rheumatoid arthritis.

Purification of naringin and neohesperidin from Huyou (Citrus changshanensis) fruit and their effects on glucose consumption in human HepG2 cells.

Huyou (Citrus changshanensis) is rich in naringin and neohesperidin, which are natural flavanone glycosides with a range of biological activities. Among the different fruit parts, i.e. flavedo, albedo, segment membrane (SM), and juice sacs (JS), albedo showed the highest contents of both compounds, with 27.00 and 19.09mg/g DW for naringin and neohesperidin, respectively. Efficient simultaneous purification of naringin and neohesperidin from Huyou albedo was established by the combination of macroporous D101 resin chromatography and high-speed counter-current chromatography (HSCCC). Purified naringin and neohesperidin were identified by both HPLC and LC-MS, and their effects on glucose consumption were investigated in HepG2 cells. Cells treated with naringin and neohesperidin showed increased consumption of glucose, and this was associated with increased phosphorylation of AMP-activated protein kinase (AMPK). Therefore, naringin and neohesperidin from Huyou may act as potential hypoglycaemic agents through regulation of glucose metabolism.

[A novel C27-steroidal glycoside sulfate from Liriope graminifolia].

An unusual novel C27-steroidal glycoside sulfate was isolated from the underground organs of Liriope graminifolia (Linn.) Baker with three known compounds. Their chemical structures were determined by spectral analysis, including HR-MS, 1D and 2D NMR as (25S)-ruscogenin 1-sulfate-3-O-alpha-L-rhamnopyranoside (1), (25S)-ruscogenin 1-O-beta-D-xylopyranosyl-3-O-alpha-L-rhamnopyranoside (2), hesperidin (3), and 4', 7-dihydroxy-5-methoxyflavanone (4). Compound 1 has cytotoxic activities against K562 and HL60 cells with IC50 values of 18.6 microg x mL(-1) and 16.5 microg x mL(-1), respectively.

Microbial metabolism. Part 13. Metabolites of hesperetin.

The fungal culture, Mucor ramannianus (ATCC 2628) transformed hesperitin (1) to four metabolites: 4'-methoxy-5,7,8,3'-tetrahydroxyflavanone (8-hydroxyhesperetin) (2), 5,7,3',4'-tetrahydroxyflavanone (eriodictyol) (3), 4'-methoxy-5,3'-dihydroxyflavanone 7-sulfate (hesperetin 7-sulfate) (4) and 5,7,3'-trihydroxyflavanone 4'-O-α-quinovopyranoside (eriodictyol 4'-O-α-quinovopyranoside) (5). The structures were established by spectroscopic methods.