Phenolics, flavonoids content and antioxidant activities of 4 Malaysian herbal plants

Water and ethanolic extracts of four Malaysian local herbs, Tenggek burung (Melicope Iunu-ankenda), Kesum (Polygonum minus), Curry leave (Murraya Koenigii) and Salam (Eugenia polyantha) were investigated for their total phenolic content (TPC), total flavonoids content (TFC) and antioxidant activities (AA). Total phenolic content (TPC) of the herbs was determined using Folin-Ciocalteu reagent assay while the total flavonoid content (TFC) was determined based on aluminium chloride-flavonoid assay. The determination of AA was done using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activitiy and β-carotene bleaching assays (BCB). Different extraction solvents significantly affected the TPC, TFC and AA of all herbs studied (p < 0.05). Both Tenggek burung and Kesum showed highest TPC, TFC and AA regardless of extraction solvents compared to Curry leave and Salam. All herbs showed strong positive correlation between TPC and DPPH assay. However, negative and low correlation between TFC and AA were obtained for all herbs studied. This showed that phenolic compounds of certain structures were responsible for the AA of all the herbs in this study. In conclusion, all herbs in this study except curry leave could be inexpensive sources of good natural antioxidants with nutraceutical potential in food industry

Carotenoids retention in leafy vegetables based on cooking methods

Green leafy vegetables are good sources of carotenoids. Generally, food composition databases related to raw foods are available, but data on cooked foods in Malaysia are still lacking. Since carotenoids are prone to degradation during cooking processes, the present study was undertaken to evaluate the extent of nutrient loss in vegetables subjected to two conventional cooking methods, which were boiling and stir-frying with cooking durations of 4 and 8 minutes. The vegetables selected were Chinese cabbage (Brassica Pekinensis var.cephalata), swamp cabbage (Ipomoea aquatica), spinach (Spinacia oleracea), Ceylon spinach (Basella rubra), red spinach (Amaranthus gangeticus), white spinach (Amaranthus viridis) and tapioca shoots(Manihot utilissima). Percentage losses of nutrients after cooking treatment were calculated based on retention factors. Results obtained showed that stir-frying had reduced lutein content for all vegetables ranging from 8-89% while the effect of boiling for lutein varied (0-428%) with different vegetables at both cooking durations of 4 and 8 min. Boiling for 8 min increased retention of β-carotene in all vegetables ranging from 18-380% except for Chinese cabbage and spinach compared with 4 min, while stir-frying generally increased the retention of β-carotene for all vegetables 2-3 times except for spinach. Cooked vegetables have variations in carotenoids composition brought by varying cooking conditions (time and temperature), type of vegetables and the interaction between cooking methods and type of vegetables

Antioxidant peptides purified and identified from the oil palm (Elaeis guineensis Jacq.) kernel protein hydrolysate

Protein extracted from oil palm kernel was hydrolyzed using pepsin-pancreatin (OPKH) and subsequently used to identify the potential antioxidative peptides. Then, the OPKH was purified sequentially by ultrafiltration, reversed-phase and semi-preparative HPLC. Antioxidant capacities (ACs) of the purified peptides from OPKH were evaluated using ferric reducing antioxidant power (FRAP), β-carotene-linoleate bleaching (BCB) assay and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activity assay. Amino acid compositions of the purified peptide fractions were also determined. The amino acid sequence of the antioxidative peptide was identified by liquid chromatography-electrospray ionization/multi-stage mass spectrometry (LC-ESI-Q-TOF-MS/MS) using de novo sequencing. There were nine fractions purified and collected where F6 demonstrated the highest AC. Three antioxidative peptides, Val-Val-Gly-Gly-Asp-Gly-Asp-Val (VVGGDGDV), Val-Pro-Val-Thr-Ser-Thr (VPVTST) and Leu-Thr-Thr-Leu-Asp-Ser-Glu (LTTLDSE) were identified in fraction F6. These peptides did not show any similarity with other antioxidant peptides listed in BLAST database of NCBI. These peptides may be useful ingredients in food and pharmaceutical applications

Ascorbic acid: properties, determination and uses

Vitamin C is one of the most important vitamins in human nutrition. However, the complexity of food matrices and the degradation of this vitamin pose huge challenges during analysis. The chemistry (spectral and physical properties), uses, and analytic methods for the determination of vitamin C are highlighted, along with the strategies used by various researchers to prevent vitamin oxidation during sample extraction. Furthermore, the advantages and disadvantages of different analytic methods, traditional and modern, are also discussed

Cytotoxicity effect of oil palm (Elaeis guineensis) kernel protein hydrolysates

This study was conducted to ascertain the cytotoxicity effect of oil palm (Elaeis guineensis) kernel protein hydrolysates (OPKHs) produced from its protein isolate. A modified microplate titer WST-1 [2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium] assay was used to investigate the cytotoxicity of hydrolysates produced from protease and pepsin-pancreatin hydrolysis at various concentrations (0.1, 1, 10, 100 μg/ml and 1 mg/ml) using HepG2 cell model. Additionally, peptide stimulation test using OPKHs at 1 mg/ml was carried out to investigate whether OPKHs could serve as growth factor for HepG2 cells other than affecting its viability. As a result, oleic acid appeared to normalize the WST-1 readings of HepG2 cells treated with both hydrolysates at 1 mg/ml. The presence of amino acids in OPKHs could stimulate the growth and prolongs the viability of HepG2 cells. Both OPKHs were non-cytotoxic to HepG2 cells at all tested concentrations even at high concentrations. This study indicated that pepsin-pancreatin and protease hydrolysates produced from oil palm kernel protein were non-cytotoxic on HepG2 cells

Investigation of the curative effects of palm vitamin E tocotrienols on autoimmune arthritis disease in vivo

The tocotrienol-rich fraction (TRF) from palm oil contains vitamin E, which possesses potent antioxidant and anti-inflammatory activities. Rheumatoid arthritis (RA) is a chronic joint inflammatory disease characterised by severe joint pain, cartilage destruction, and bone erosion owing to the effects of various pro-inflammatory mediators and cytokines. Here, we investigated the therapeutic effects of TRF in a rat model of collagen-induced arthritis (CIA). Arthritis was induced by a single intradermal injection of collagen type II in Dark Agouti (DA) rats. Rats were then treated with or without TRF by oral gavage from day 28 after the first collagen injection. Arthritic rats supplemented with TRF showed decreased articular index scores, ankle circumferences, paw volumes, and radiographic scores when compared with untreated rats. The untreated arthritic rats showed higher plasma C-reactive protein levels (p < 0.05) and production of pro-inflammatory cytokines than arthritic rats fed TRF. Moreover, there was a marked reduction in the severity of histopathological changes observed in arthritic rats treated with TRF compared with that in untreated arthritic rats. Overall, the results show that TRF had beneficial effects in this rat model of RA

Effects of oil palm tocotrienol rich fraction on the viability and morphology of astrocytes injured with glutamate

Tocotrienol-rich fraction (TRF) is an extract of palm oil that consists of 25% α-tocopherol and 75% tocotrienols. TRF was shown to possess antioxidant, anti-inflammatory, anticancer, neuroprotective and cholesterol-lowering activities. Glutamate is the major mediator of excitatory signals in the mammalian central nervous system. Extreme amounts of glutamate in the extracellular spaces can lead to numerous neurodegenerative diseases. Hence, the efficacy of oil palm TRF and α-tocopherol in protecting astrocytes against glutamate-induced cell death was studied. Specifically, the effectiveness of pre- or post-treatment of TRF and α-tocopherol upon glutamate excitotoxicity was determined by evaluating cell viability and morphology of astrocytes. Cell viability was measured using MTT assay while cell morphology was monitored under fluorescent microscope using the acridine orange/propidium iodide (AO/PI) assay. Exposure to 230 mM glutamate significantly reduced cell viability to 50% in both the pre- and post-treatment studies; however, pre- and post-treatment with TRF and α-tocopherol attenuated the cytotoxic effect of glutamate. Compared to glutamate-injured astrocytes, pre-treatment with 100, 200 and 300 ng/ml TRF significantly improved cell viability following glutamate injury to 86.6%, 86.7% and 93.9%, respectively (p < 0.05). On the contrary, high concentrations of α-tocopherol promote cell death. This study shows that TRF not only provide a better protection against glutamate toxicity (pre-treatment), but was also able to reverse the lipid peroxidation resulting from glutamate insults (post-treatment). The present results demonstrate that TRF, but not α-tocopherol, protected the astrocytes against glutamate-induced cell death, indicating its neuro-protective potential

Therapeutic potential of palm oil vitamin E-derived tocotrienols in inflammation and chronic diseases: Evidence from preclinical and clinical studies

Palm oil is rich in tocotrienols (T3s), a type of vitamin E that has garnered considerable research interest as it exhibits anti-inflammatory as well as antioxidant characteristics that are comparable to or exceed those of tocopherols (Toc). Notably, T3 must be consumed as it cannot be produced by the human body. Here, we reviewed the anti-inflammatory activities of T3s in the prevention and treatment of various inflammatory disorders; focusing on recent preclinical and clinical studies. There is compelling data from experimental models and human studies that shows that T3 administration can inhibit the release of various inflammatory mediators that contribute to age-related disease by enhancing oxidative stress, reducing melanin production and skin damage, and preventing cardiovascular disease and stroke. There is evidence to show that T3s possess neuroprotective, anticancer, and anti-osteoporosis properties. In addition, T3s also protect the gastrointestinal tract, facilitate blood glucose control in people with diabetes, and prevent fatty liver disease. Furthermore, results from some clinical studies suggest that T3s are beneficial nutritional supplements with no evident side-effects when administered to patients with neurological or cardiovascular disorders. There is growing evidence from clinical trials that shows that T3s can help prevent dementia and Alzheimer's disease. More well-designed clinical trials, as well as human intervention studies, are required to confirm the health benefits of palm T3

Effects of palm oil tocotrienol-rich fraction (TRF) and carotenes in ovalbumin (OVA)-challenged asthmatic Brown Norway rats

Synthetic therapeutic drugs for asthma, a chronic airway inflammation characterised by strong eosinophil, mast cell, and lymphocyte infiltration, mucus hyper-production, and airway hyper-responsiveness, exhibit numerous side effects. Alternatively, the high antioxidant potential of palm oil phytonutrients, including vitamin E (tocotrienol-rich fractions; TRF) and carotene, may be beneficial for alleviating asthma. Here, we determined the therapeutic efficacy of TRF, carotene, and dexamethasone in ovalbumin-challenged allergic asthma in Brown Norway rats. Asthmatic symptoms fully developed within 8 days after the second sensitization, and were preserved throughout the time course via intranasal ovalbumin re-challenge. Asthmatic rats were then orally administered 30 mg/kg body weight TRF or carotene. TRF-treated animals exhibited reduced inflammatory cells in bronchial alveolar lavage fluid. TRF- and carotene-treated rats exhibited notable white blood cell reduction comparable to that from dexamethasone. TRF- and carotene-treatment also downregulated pro-inflammatory markers (IL-β, IL-6, TNF-α), coincident with anti-inflammatory marker IL-4 and IL-13 upregulation. Treatment significantly reduced asthmatic rat plasma CRP and IgE, signifying improved systemic inflammation. Asthmatic lung histology displayed severe edema and inflammatory cell infiltration in the bronchial wall, whereas treated animals retained healthy, normal-appearing lungs. The phytonutrients tocotrienol and carotene thus exhibit potential benefits for consumption as nutritional adjuncts in asthmatic disease

Detection of fresh palm oil adulteration with recycled cooking oil using fatty acid composition and FTIR spectral analysis

There is a growing concern over the food safety issue related to increased incidence of cooking oil adulteration with recycled cooking oil (RCO). The objective of this study was to detect fresh palm olein (FPO) adulteration with RCO using fatty acid composition (FAC) and Fourier-transform infrared spectroscopy (FTIR) spectral analyses combined with chemometrics. RCO prepared in the laboratory was mixed with FPO in the proportion ranged from 1% to 50% (v/v) to obtain the adulterated oil samples (AO). FACs for FPO, RCO, and AO were determined using gas chromatography equipped with a flame ionization detector (GC-FID). The compositions of most fatty acids in RCO lied within the normal ranges of Codex standard, except for C8:0, C10:0, C11:0, C15:0, trans C18:1, and polyunsaturated fatty acids (PUFAs), C20:5. PUFAs showed a consistent decreasing trend with increasing magnitude of change with respect to increasing adulteration level and thus might be a good indicator for detecting FPO adulteration with RCO. The evaluation parameters (coefficient of determination, root mean standard error) of the FTIR-partial least square (PLS) model of palm oil adulteration with recycled oil are R2 = 0.995 and 3.25, respectively. For FTIR spectral analysis, the distinct variations in spectral regions and aberrations in characteristic bands between FPO and RCO were observed. The optimized PLS calibration model developed from normal spectral of the combined region at 3602–3398, 3016–2642, and 1845–650 cm−1 overpredict the adulteration level. On the other hand, the discriminant analysis classification model was able to classify the FPO and AO into two distinct groups. Improvement of the principles of combined techniques in authenticating AO from fresh oil is beneficial as a guideline to detect adulteration in cooking oil