Antioxidant activity of different extracts of red pitaya (Hylocereus polyrhizus) seed

Antioxidant activity of three different extracts (ethanolic, chloroformic, and hexanic) of red flesh pitaya (Hylocereus polyrhizus) seed using free radical scavenging assay, linoleic acid model system, and ferric thiocyanate (FTC) method was determined. Ethanolic extract inhibit 74.76% of free radicals at 1000 μg/mL, while chloroformic extract gave the highest inhibition using linoleic acid model system (98.90% at 100 μg/mL) and FTC (96.34%) method. Total phenolic and ascorbic acid contents of the seed were 13.56 ± 2.04 and 0.36 ± 0.01 mg/g, respectively, while catechin was the major flavonoid detected. In conclusion, the study showed that both polar and non-polar compounds contribute to the antioxidative activity measured

Effect of boiling and stir frying on total phenolics, carotenoids and radical scavenging activity of pumpkin (Cucurbita moschato)

Effect of various cooking methods on antioxidant content and radical scavenging activity of pumpkin was evaluated. Pumpkin (Cucurbita moschata) was boiled and stir-fried for 2, 4 and 6 minutes respectively. Beta-carotene and lycopene were determined using HPLC and total phenolics measured using Folin-Ciocalteu method. The free radical scavenging activity of the samples was determined using 1, 1-diphenyl-2-picrylhydrazyl assay. Interestingly, result of the study showed an increase in both beta-carotene (2 to 4 times) and lycopene (17 to 40 times) content of pumpkin after cooking for 2, 4 and 6 minutes. However, the treatment resulted in 18 to 54% losses of total phenolics content of the pumpkin. Nevertheless, the free radical scavenging activity exhibited by cooked pumpkins was found to be high, in the range of 81.1% to 94.6% with IC50 of 1.41 to 1.62mg ml-1

Antioxidative activities of chromatographic fractions obtained from root, fruit and leaf of Mengkudu (Morinda citrifolia L.)

Crude extracts of root, leaf and fruit of Morinda citrifolia were fractionated on a Sephadex LH-20 column with ethanol as eluate. Based on UV absorption intensity of phenolic compound (725 mm) the Sephadex LH-20 column was able to separate fruit, leaf and root extracts into six, five and five fractions, respectively. The results showed that all the fractions tested exhibited considerably high antioxidative activity in the ferric thiocyanate assay and thiobarbituric acid test and the activities of some of the fractions were as good as those of either tocopherol or BHT. The fractions from different parts of the plants were found to contain different amounts of total phenolic compounds, which, interestingly, do not correspond to the antioxidative activity measured. This is probably due to the presence of different phenolics in the samples, with different antioxidative activities which involves various mechanisms inhibiting the oxidation process. The study suggested that root, leaf and fruit of M. citrifolia might contribute significantly to exogenous antioxidant which is crucial in combating oxidative stress

Extraction and determination of oryzanol in rice bran of mixed Herbarium UKMB; AZ 6807: MR 185, AZ 6808: MR 211, AZ6809: MR 29

The level of total lipid and oryzanol content, an important antioxidant compound in locally produced bran was investigated. Total lipid in rice bran was extracted using 3:2 chloroform:methanol mixture yielding 16.4% fat. Oryzanol content was determined without saponification using a reverse-phase HPLC. Four fractions of oryzanol were successfully separated and quantitated. The 4 isomers were cycloartenyl ferulate, 24-methylene cycloartanyl ferulate, campestryl ferulate and mixtures of β–sitosteryl ferulate and cycloartanyl ferulate. The oryzanol content of local mixed varieties ranged from 23.7–43.0 mg g-1. The oryzanol concentration may depend on factors such as plant varieties, processing methods employed, extracting solvent used and ratio of extracting solvent to bran as well as extracting solvent temperatures. This study showed the potential of oryzanol extract from rice bran as a source of antioxidant

Strobilanthes crispus leaves extracts (SCE) induced lipolysis and increased leptin level in diet-induced obese rats fed high-fat diet

The aim of the present study was to assess the anti-obesity and lipolysis effects of Strobilanthes crispus leaves extract (SCE) in diet-induced obese (DIO) rats by administering 1% (w/w) of SCE in drinking water. Methods: Normal Sprague-Dawley rats were induced obese using a high-fat (HF) diet formulation for 14 weeks. DIO rats were subsequently treated with 1% (w/w) SCE while the HF diet was switched to normal rat chow diet. Food intake, water intake and bodyweight were measured weekly. Other parameters e.g. blood lipid profile were determined in normal and DIO rats before and after treatment with SCE. Histopathological changes in the liver were also observed after treatment. Results: Prior to treatment, DIO rats have significantly higher (p < 0.05) bodyweight, adipose tissue and liver weight, plasma leptin levels, lower adipose tissue lipolysis rate and severe fatty livers and the trend continues in non-treated DIO rats served as Control group. DIO rats treated with SCE significantly (p < 0.05) reduced their bodyweight gain, have lower adipose tissue and liver weight, lower leptin level and increased lipolysis rate although no significant effect was found in total bodyweights of treated group. Lower glucose level and improved state of fatty liver was also noted in SCE treated group. The observed anti-obesity effects are most likely the due to lipolysis. Conclusion: SCE may, at least in part, be attributed to the anti-obesity effects found on treated DIO rats

Preliminary study of the chemical composition of rice milling fractions stabilized by microwave heating

The present paper presents a preliminary study of the chemical composition of local stabilized rice bran. The four rice-bran milling fractions, after stabilization by microwave heating on site at the rice mill, were analyzed for their chemical composition. The content of all fractions tested (in g/100 g) consisted of 8.7–18.9 fat, 8.8–15.2 protein, 8.5–12.6 moisture, 4.2–7.7 ash, 22.2–44.8 total carbohydrates (by difference) and 18.3–30.5 total dietary fibre. It is encouraging to note that total phenolic compounds of all fractions were detected at 257–488 mg ferulic acid equivalent per 100 kg, while carotenoid contents were found to be in the range of 58.7–216 μg/100 g. The amino acid composition varied within wide limits with proline, histidine and threonine as the amino acids. Higher concentrations of amino acids found (in decreasing order) were arginine, glutamic acid, aspartic acid and serine. Phosphorus and potassium were among the major mineral constituents of rice bran, with values up to 1633 mg/100 g. The first rice bran fraction was found to be highest in energy, fat and minerals and could be a very good source of dietary fiber and other nutrients

Inhibitory effect of Morinda citrifolia L. on lipoprotein lipase activity.

Efficacy of Morinda citrifolia L. leaf (MLE) and fruit extracts (MFE) in inhibiting lipoprotein lipase (LPL) was determined in vitro. The result of the study showed that the highest inhibition on the LPL activity was exhibited by MLE (66%± 2.1%), which is significantly higher than that demonstrated by MFE (54.5%± 2.5%), green tea extract (GTE) (54.5%± 2.6%), and catechin (43.6%± 6.1%). Percent of LPL inhibition increase with concentration of the extracts. Quantitative analysis of the extracts revealed the presence of high levels of (+)−catechin at 63.5 ± 17 and 53.7 ± 5.7 mg/g in MLE and MFE, respectively, although not as high as that found in GTE (530.6 ± 42 mg/g). Appreciable amount of epicatechin was found in all extracts tested, while rutin was only found in MLE and MFE. The study suggested that both leaf and fruit of M. citrifolia may be used as antiobesity agents in body weight management

Physico-chemical and structural changes of red-fleshed dragon fruit (Hylocereus polyrhizus) during fruit development

BACKGROUND: Determination of physico-chemical (weight, length, diameter, stomatal density, respiration rate, colour, soluble solids concentration, titratable acidity, chlorophyll and betacyanin content) and structural changes of red-fleshed dragon fruit (Hylocereus polyrhizus (Weber) Britton & Rose) was carried out from 5 to 35 days after pollination (DAP) in order to explain their growth, development, maturations and ripening stages. RESULTS: Fruit growth of red-fleshed dragon fruit followed a sigmoid growth pattern. Significant changes in colour were obtained in both peel and pulp as DAP progressed, which were indicated by reductions of L*, C* and h° values as both changed from green to red-violet colour at ripening. Red-violet betacyanin was manifested earlier in pulp at 25 DAP, followed by peel 4-5 days later, and finally both peel and pulp turned full red-violet by 30 DAP. There was a significant increase in soluble solids concentration and titratable acidity with the continuous increase in betacyanin content as DAP progressed. CONCLUSION: The physico-chemical and betacyanin accumulation of red-fleshed dragon fruit changed as it developed, matured and ripened which coincided with structural changes

Optimization of pulsed ultrasound-assisted technique for extraction of phenolics from pomegranate peel of Malas variety: punicalagin and hydroxybenzoic acids

Pomegranate peel is a rich source of phenolic compounds (such as punicalagin and hydroxybenzoic acids). However, the content of such bioactive compounds in the peel extract can be affected by extraction type and condition. It was hypothesized that the optimization of a pulsed ultrasound-assisted extraction (PUAE) technique could result in the pomegranate peel extract with higher yield and antioxidant activity. The main goal was to optimize PUAE condition resulting in the highest yield and antioxidant activity as well as the highest contents of punicalagin and hydroxybenzoic acids. The operation at the intensity level of 105 W/cm2 and duty cycle of 50% for a short time (10 min) had a high efficiency for extraction of phenolics from pomegranate peel. The application of such short extraction can save the energy and cost of the production. Punicalagin and ellagic acid were the most predominant phenolic compounds quantified in the pomegranate peel extract (PPE) from Malas variety. PPE contained a minor content of gallic acid