[Bioassay-guided isolation of functional components from hot water extract of Chlorella pyrenoidosa].

The main functional ingredients of hot water extract of Chlorella pyrenoidosa (CPE) were investigated through a bioassay-guided fractionation based on free radical scavenging and macrophage proliferation effects. The main functional ingredients of CPE were polysaccharides (PS) that were isolated by high pressure extraction, Sevag method, ethanol precipitation and ultrafiltration separation. Crude polysaccharides were further separated and purified by ion exchange chromatography DEAE52 and size exclusion chromatography Sephadex G-100. The purified fractions were analyzed by gel permeation chromatography. Molecular weights of the purified fractions PS-1-4-2, PS-1-3-2 and PS-2-3-3 were 3.97×104, 2.28×104 and 4.1×10³ Da, respectively. Bioassay-guided fractionation results indicated that CPE could remove free radicals and promote Ana-1 cells proliferation, mainly due to its various components working together. The components of free radicals scavenging mainly concentrated in PS-1-3, PS-1-4, PS-2-3 and PS-2-4. The components of Ana-1 proliferation mainly concentrated in PS-1-3, PS-1-4 and PS-2-3. This study established the activity screening method of main functional component from CPE, and got three new functional ingredients. It can be used to guide the development of high value products, further promote the industrialization process of microalgae energy, and realize microalgae 'high value products, microalgae energy and microalgae carbon' integration of exemplary role.

[Research status and prospect on hot water extract of Chlorella: the high value-added bioactive substance from Chlorella].

Chlorella is nutritious and has been used as a functional food much earlier than the other microalgae. C. pyrenoidosa, the potential microalgae which is currently cultured and developed for the new strategic industry of biofuels production and biological CO2 fixation, is a new resource food announced by the Ministry of Health of the People's Republic of China late 2012. Accumulation of high value-added substances in C. pyrenoidosa during the cultivation for lipid makes it possible to reduce the costs for C. pyrenoidosa-based biofuels production. Among these potential substances, hot water extract of Chlorella (CE), commercially known as "Chlorella growth factor", is the unique one that makes Chlorella more precious than the other algae, and the market price of CE is high. It is believed that CE is effective in growth promotion and immunoregulation. However, there is no systematic analysis on the research status of CE and its bioactivity. The present report summarized recent research progress of CE and its bioactivity. Generally, besides the main effect on immunoregulation and tumor inhibition, CE was efficient in improving metabolic syndrome, scavenging for free radicals, protecting against ultraviolet damage, chelating heavy metals, and protecting liver and bowel. Several major challenges in CE research as well as its prospects were also analysed in the present report.

A comparison on the preparation of hot water extracts from Chlorella pyrenoidosa (CPEs) and radical scavenging and macrophage activation effects of CPEs.

Development of hot water extracts of Chlorella pyrenoidosa (CPE) may help in the reduction of the cost involved in C. pyrenoidosa-based biofuel production. The current extraction conditions of CPE greatly vary and the CPE-related research are developing rather slowly. To find an effective preparation method, in the present study, we have prepared CPEs using high pressures, ultrasonication, and enzymolysis, and we have compared the yields, general ingredients, and bioactivities of these products. The yields of the high pressure and enzymolysis methods were more than 25%. CPE-a, which has been prepared under an extra 0.1 MPa pressure in an autoclave, was rich in protein, and it had the strongest absorbance at 260 and 280 nm, whereas CPE-c and CPE-d, which were prepared via the enzymolysis of cellulase and pectinase, had higher sugar content. The CPEs had no inhibitory influence on the formation of advanced glycation end products, and their metal chelating activities were poor. However, all the products had significant positive effects on in vitro free radical scavenging and macrophage growth promotion. Hydroxyl radicals were scavenged in a concentration-dependent manner by CPE-a, and the cultured macrophage Ana-1 proliferated to 162.98% of the control when CPE-a was administrated at 200 µg mL(-1). Furthermore, phagocytic activity and intracellular nitric oxide levels of Ana-1 were significantly enhanced with the administration of CPE-a. In brief, our results suggest that hot water extraction with high pressure is an effective method for preparing high value-added bio-products from C. pyrenoidosa, which have strong potential for use in free radical scavenging and macrophage activation.

Effects of zinc and manganese on advanced glycation end products (AGEs) formation and AGEs-mediated endothelial cell dysfunction.

AIMS: The present study investigated the effects of ZnCl2 and MnCl2 supplementations on advanced glycation end products (AGEs) formation and AGEs-mediated endothelial cell dysfunction. MAIN METHODS: Fluorescence detection was used to monitor the Maillard reaction. Inductively coupled plasma optical emission spectroscopy was used to test cellular zinc and manganese levels. Real-time reverse transcription polymerase chain reaction and western blot were used to analyze the expression of endothelial nitric oxide synthase (eNOS), nuclear transcription factor kappa B (NF-κB), and receptor for AGEs (RAGE). Intracellular reactive oxygen species (ROS) and nitric oxide (NO) production, NOS activity were determined by fluorescent probe assay, superoxide dismutase (SOD) activity was determined by water soluble tetrazolium salt assay. KEY FINDINGS: MnCl2 showed excellent inhibitory effect on AGEs formation. Primary cultured bovine aortic endothelial cells (BAECs) were exposed to AGEs for 30 min, followed by trace element treatments. Cell viability and the zinc levels declined due to AGEs exposure, which were improved with the supplementations of ZnCl2 and MnCl2. Furthermore, ZnCl2 supplementation effectively enhanced intracellular NO production, elevated eNOS expression and enzymatic activity, and down-regulated NF-κB activation and RAGE expression. MnCl2 dose-dependently impaired ROS formation, down-regulated NF-κB protein expression and nuclear translocation, as well as restored Mn-SOD enzymatic capability. SIGNIFICANCE: Our findings suggested that trace elements relevant to diabetic, such as zinc and manganese played different roles in the formation of AGEs. Both the elements benefited the AGEs-injured BAECs through different mechanisms.

Hypoglycemic effect of aqueous extract of seabuckthorn (Hippophae rhamnoides L.) seed residues in streptozotocin-induced diabetic rats.

An extract of seabuckthorn (Hippophae rhamnoides L.) seed residues has been shown to possess hypoglycemic and hypolipidemic properties in normal mice. The present study investigated the effects of an aqueous extract of seabuckthorn seed residues (ASSR) on serum glucose, lipid profiles and antioxidant parameters in streptozotocin-induced diabetic rats. Male Sprague-Dawley rats were divided into four groups: a normal control group; diabetic control group; diabetic groups supplemented with 5 mg/kg body weight glibenclamide (reference drug) and 400 mg/kg body weight ASSR. Diabetes in rats was induced by intraperitoneal injection of streptozotocin (45 mg/kg body weight). Vehicle (distilled water), glibenclamide and ASSR were administered orally to normal and diabetic rats once a day lasting for 4 weeks. The data showed that administration of ASSR significantly lowered the serum glucose, triglyceride and nitric oxide levels in diabetic rats. Moreover, ASSR treatment also increased serum superoxide dismutase activity and glutathione level markedly. These results show that ASSR has hypoglycemic, hypotriglyceridemic and antioxidant effects in streptozotocin-induced diabetic rats, suggesting that ASSR supplementation can be useful in preventing diabetic complications associated with hyperlipidemia and oxidative stress.

Antihypertensive effect of total flavones extracted from seed residues of Hippophae rhamnoides L. in sucrose-fed rats.

The study was designed to investigate the antihypertensive effect of total flavones extracted from seed residues of Hippophae rhamnoides L. (TFH-SR) and its underlying mechanism in chronic sucrose-fed rats by evaluating its ability to regulate insulin and angiotensin || levels. Feeding of high-sucrose diet (HS: 77% of kcal from carbohydrate, 16% from protein and 6% from lipid, respectively) for 6 weeks resulted in significant rise in systolic blood pressure (SBP) by 25.60%, plasma insulin by 114.24%, triglycerides by 85.14% and activated angiotensin || contents in heart and kidney. However, TFH-SR treatment significantly suppressed the elevated hypertension, hyperinsulinemia and dyslipidemia. Furthermore, TFH-SR (especially at the dose of 150mg/kg/day) increased the circulatory blood angiotensin || level as effective as angiotensin || receptor blocker. These results indicated that TFH-SR exerted its antihypertensive effects at least in part by improving insulin sensitivity and blocking angiotensin || signal pathway. Findings of the present study suggested that TFH-SR might prove to be of potential use in the management of hyperinsulinemia in non-diabetic state with cardiovascular diseases.

[Investigation on inhibitory and apoptosis-inducing effects of saponins from Tribulus terrestris on hepatoma cell line BEL-7402].

OBJECTIVE: To investigate the inhibitory and apoptosis-inducing effects of saponins from Tribulus terrestris (STT) on liver cancer cell line BEL-7402. METHOD: MTT, SRB, Wright staining, acridine orange staining, flow cytometry, and Immunofluorescence microscopy were used to evaluate the effects of STT on BEL-7402 cell line. RESULT: SMT had potent inhibitory effect on BEL-7402 cell line in a concentration-dependent manner. BEL-7402 cells exibited typical morphological alteration of apoptosis when sub-G1 peak could be seen. The expression of Bcl-2 was decreased in STT treated cells as compared with untreated control cells. CONCLUSION: STT exerts its cytotoxic effect on BEL-7402 cells by inducing apoptosis.

[Study on effect of flavonoids from oil-removed seeds of Hippophae rhamnoides on inducing apoptosis of human hepatoma cell].

OBJECTIVE: To investigate the inhibitory and apoptosis-inducing effects of flavonoids from oil-removed seeds of Hippophae rhamnoides (FSH) on liver cancer cell line BEL-7402. METHODS: SRB, Wright staining, electron microscope and flow cytometry are used to study the effects of STT on BEL-7402 cell line. RESULTS: FSH has potent inhibitive effect on BEL-7402 cell line in a concentration-dependent manner. BEL-7402 cells exhibit typical morphological alteration of apoptosis when sub-Gl peak can be seen. CONCLUSION: FSH exerts its inhibitive effect on BEL-7402 cells by inducing apoptosis.