Phenolic composition, antioxidant and antimicrobial activities of free and bound phenolic extracts of Moringa oleifera seed flour

Phytochemicals of Moringa oleifera: a review of their nutritional, therapeutic and industrial significance

Moringa oleifera Lam., also known as the ‘drumstick tree,’ is recognized as a vibrant and affordable source of phytochemicals, having potential applications in medicines, functional food preparations, water purification, and biodiesel production. The multiple biological activities including antiproliferation, hepatoprotective, anti-inflammatory, antinociceptive, antiatherosclerotic, oxidative DNA damage protective, antiperoxidative, cardioprotective, as well as folk medicinal uses of M. oleifera (MO) are attributed to the presence of functional bioactive compounds, such as phenolic acids, flavonoids, alkaloids, phytosterols, natural sugars, vitamins, minerals, and organic acids. The low molecular weight of M. oleifera cationic proteins (MOCP) extracted from the seeds is very useful and is used in water purification, because of its potent antimicrobial and coagulant properties. Also, the M. oleifera methyl esters (MOME) produced from the oil of the seeds meet the major specifications of the biodiesel standard of Germany, Europe, and United States (US). Thus, MO is emerging as one of the prominent industrial crops for sustainable biodiesel production in tropical and subtropical countries. In view of the high nutritional, nutraceutical, and industrial values, it is important to compile an updated comprehensive review on the related aspects of this multipurpose and miracle tree. Hence, the present study is focused on the nutritionally significant bioactives and medicinal and biological properties, to explore the potential applications of MO in nutritionally rich food preparations. Furthermore, water coagulation, proteins, and fatty acid methyl esters from the MO seeds are reviewed, to explore their possible industrial applications in biodiesel production and water purification. In addition, the future perspectives in these areas are suggested.

Insoluble-Bound Phenolics in Food

This contribution provides a review of the topic of insoluble-bound phenolics, especially their localization, synthesis, transfer and formation in plant cells, as well as their metabolism in the human digestive system and corresponding bioactivities. In addition, their release from the food matrix during food processing and extraction methods are discussed. The synthesis of phenolics takes place mainly at the endoplasmic reticulum and they are then transferred to each organ through transport proteins such as the ATP-binding cassette (ABC) and multidrug and toxic compound extrusion (MATE) transporter at the organ’s compartment membrane or via transport vesicles such as cytoplasmic and Golgi vesicles, leading to the formation of soluble and insoluble-bound phenolics at the vacuole and cell wall matrix, respectively. This part has not been adequately discussed in the food science literature, especially regarding the synthesis site and their transfer at the cellular level, thus this contribution provides valuable information to the involved scientists. The bound phenolics cannot be absorbed at the small intestine as the soluble phenolics do (5%–10%), thus passing into the large intestine and undergoing fermentation by a number of microorganisms, partially released from cell wall matrix of foods. Bound phenolics such as phenolic acids and flavonoids display strong bioactivities such as anticancer, anti-inflammation and cardiovascular disease ameliorating effects. They can be extracted by several methods such as acid, alkali and enzymatic hydrolysis to quantify their contents in foods. In addition, they can also be released from the cell wall matrix during food processing procedures such as fermentation, germination, roasting, extrusion cooking and boiling. This review provides critical information for better understanding the insoluble-bound phenolics in food and fills an existing gap in the literature.

Miracle Fruit (Synsepalum dulcificum) Exhibits as a Novel Anti-Hyperuricaemia Agent

Miracle fruit (Synsepalum dulcificum) belongs to the Sapotaceae family. It can change flavors on taste buds, transforming acidic tastes to sweet. We evaluated various miracle fruit extracts, including water, butanol, ethyl acetate (EA), and hexane fractions, to determine its antioxidant effects. These extracts isolated from miracle fruit exerted potential for reduction of uric acid and inhibited xanthine oxidase activity in vitro and in monosodiumurate (MSU)-treated RAW264.7 macrophages. Moreover, we also found that the butanol extracts of miracle fruit attenuated oxonic acid potassium salt-induced hyperuricaemia in ICR mice by lowering serum uric acid levels and activating hepatic xanthine oxidase. These effects were equal to those of allopurinol, suggesting that the butanol extract of miracle fruit could be developed as a novel anti-hyperuricaemia agent or health food.

Relative bioavailability of folate from the traditional food plant Moringa oleifera L. as evaluated in a rat model

Moringa oleifera is an affordable and rich source of dietary folate. Quantification of folate by HPLC showed that 5-formyl-5,6,7,8-tetrahydrofolic acid (502.1 μg/100 g DW) and 5,6,7,8-tetrahydrofolic acid (223.9 μg/100 g DW) as the most dominant forms of folate in M. oleifera leaves. The bioavailability of folate and the effects of folate depletion and repletion on biochemical and molecular markers of folate status were investigated in Wistar rats. Folate deficiency was induced by keeping the animals on a folate deficient diet with 1 % succinyl sulfathiazole (w/w). After the depletion period, animals were repleted with different levels of folic acid and M. oleifera leaves as a source of folate. Feeding the animals on a folate deficient diet for 7 weeks caused a significant (3.4-fold) decrease in serum folate content, compared to non-depleted control animals. Relative bioavailability of folate from dehydrated leaves of M. oleifera was 81.9 %. During folate depletion and repletion, no significant changes in liver glycine N-methyl transferase and 5-methyltetrahydrofolate-homocysteine methyltransferase expression were recorded. In RDA calculations, only 50 % of natural folate is assumed to be bioavailable. Therefore, the bioavailability of folate from Moringa is much higher, suggesting that M. oleifera based food can be used as a significant source of folate.

Adjuvant properties of water extractable arabinoxylans with different structural features from wheat flour against model antigen ovalbumin

Despite the numerous benefits of AX on the immune system and gut bacteria, the potential adjuvant activity of WEAX on immune responses has not been adequately investigated.

Nepenthes khasiana mediated synthesis of stabilized gold nanoparticles: Characterization and biocompatibility studies

The current study summarizes a unique green process for the synthesis of gold nanoparticles by simple treatment of gold salts with aqueous extract of Nepenthes khasiana (NK)--a red listed medicinal plant and its characterization. Study on the effect of different process parameters like temperature, pH and stirring on surface and stability characteristics has been demonstrated. Formation of GNPs was visually observed by change in color from colorless to wine red and characterized by UV-Visible spectroscopy, FT-IR spectroscopy, Zetasizer, X-RD, ICP-AES, SEM-EDAX, AFM and TEM. In vitro stability studies of gold colloidal dispersion in various blood components suggest that, NK mediated GNPs exhibit remarkable in vitro stability in 2% bovine serum albumin, 2% human serum albumin (HSA), 0.2M histidine, and 0.2M cysteine but unstable in 5% NaCl solution and acidic pH. Biocompatibility of NK stabilized GNPs against normal mouse fibroblasts (L929) cell lines revealed nontoxic nature of GNPs and thus provides exceptional opportunities for their uses as nanomedicine for diagnosis and drug therapy. The role of antioxidant phytochemicals (flavonoids and polyphenols) of NK extract in synthesis of biocompatible and stabilized GNPs was demonstrated by estimating total flavonoid content, total phenolic content and total antioxidant capacity of extract before and after formation of GNPs. Fast and easy synthesis of biocompatible GNPs possesses unique physical and chemical features which serve as an advantage for its use in various biomedical applications. The overall approach designated in the present research investigation for the synthesis of GNPs is based on all 12 principles of green chemistry, in which no man-made chemical other than the gold chloride was used.

Phytochemical composition, GC-MS analysis, in vitro antioxidant and antibacterial potential of clove flower bud (Eugenia caryophyllus) methanolic extract

Plant derived pharmacologically active compounds have gained importance in food and pharmaceutical industries. The aim of the present study is to identify and study the antioxidant, antimicrobial properties of the phytochemicals present in the crude extract of Eugenia caryophyllus flower buds. The antioxidant activity of the methanol, acetone and chloroform extract was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The methanol extract showed better radical scavenging activity than other selected solvents. Preliminary screening of phytochemicals was carried out in methanol extract and total phenol content was found high. Antibacterial activity was determined by well diffusion assay and methanol extract was found effective against Klebsiella pneumonia. FTIR and GC-MS results indicate the presence of aromatic compounds and major constituents were found to be eugenol and eugenyl acetate. Results of this study implied that Eugenia caryophyllus flower bud extract could be considered as health nutriments in food and pharmaceutical industries.

RETRACTED: Green synthesis of zinc oxide nanoparticles using Moringa oleifera leaf extract and evaluation of its antimicrobial activity

The development of semiconductor materials made a considerable progress of catalytic technologies. In the present study, a simple and eco-friendly chemical direction for the synthesis of zinc oxide nanoparticles (ZnO NPs) using leaf extract of Moringa oleifera has been used. The prepared ZnO NPs were characterized various techniques such as UV-Vis absorption spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FT-IR) and photoluminescence spectroscopy (PL). XRD analysis revealed the wurtzite hexagonal structure of ZnO NPs. FT-IR confirmed the presence of functional groups of both leaf extract and ZnO NPs. The particles size, morphology and topography determined from FE-SEM. The intense and narrow width of zinc and oxygen have high purity and crystalline were identified using EDX. UV-Vis absorption showed the characteristic absorption peak of ZnO NPs. The results of antimicrobial activities revealed that maximum zones of inhibition was observed Gram (+ve) positive bacteria and followed by the Gram (-ve) negative bacteria and fungal at concentration of 200μg/mL of ZnO NPs.

Chemical constitution and effect of extracts of tomato plants byproducts on the enteric viral surrogates

Byproducts of tomato are known to include phenolic compounds but have not been studied in depth. In this study, the phenolic compositions of (stem, leaf, root, and whole plant) of two tomato cultivars, Pitenza and Floradade, were analyzed by HPLC-DAD. In parallel, the antiviral effects of crude extracts on viral surrogates, the bacteriophages MS2 and Av-05 were evaluated. The leaf extracts from the two varieties showed the highest concentration of phenolic compounds. The compounds identified were gallic acid, chlorogenic acid, ferulic acid, cafeic acid, rutin, and quercetin, and they represented 3174.3 and 1057.9 mg/100 g dried weight of the Pitenza and Floradade cultivars, respectively. MS2 and Av-05 titers at 5 mg/mL were reduced by 3.47 and 5.78 log10 PFU/mL and 3.78 and 4.93 log10 PFU/mL by Pitenza and Floradade cultivar leaf extract, respectively. These results show that tomato extracts are natural sources of bioactive substances with antiviral activity.

Antioxidative and antimicrobial activities of the extracts from the seed coat of Bambara groundnut (Voandzeia subterranea)

Antioxidative and antimicrobial activities of extracts from Bambarra groundnut seed coat, prepared using water, ethanol and acetone as the media at various temperatures (30, 60, 90 °C) were investigated.

Antioxidant, antimicrobial and phytochemical variations in thirteen Moringa oleifera Lam. cultivars

A study was undertaken to assess variation in antioxidant, antimicrobial and phytochemical properties of thirteen Moringa oleifera cultivars obtained from different locations across the globe. Standard antioxidant methods including the DPPH scavenging, ferric reducing power (FRAP) and β-carotene-linoleic acid model were used to evaluate the activity. Variation in the antioxidant activity was observed, with TOT4951 from Thailand being the most active, with activity five times higher than that of ascorbic acid (reference compound). A different trend was observed for the activity in the FRAP and β-carotene-linoleic acid assays. Antimicrobial activity was tested against Gram-positive (Staphylococcus aureus) and Gram-negative (Klebsiella pneumoniae) strains using the microdilution method. Acetone extracts of all cultivars exhibited good antibacterial activity against K. pneumoniae (MIC values of 0.78 mg/mL). The remaining extracts exhibited weak activity against the two microorganisms. For the antifungal activity, all the extracts exhibited low activity. Variations were observed in the total phenolic and flavonoid contents. Cultivars TOT5169 (Thailand) and SH (South Africa) exhibited highest amounts of total phenolic compounds while TOT5028 (Thailand) exhibited the lowest amounts of five times lower than the highest. The information offer an understanding on variations between cultivars from different geographical locations and is important in the search for antioxidant supplementation and anti-ageing products.