Total Phenolic Content Of Extracts Research Articles

Antioxidant and antibacterial evaluation of Manuka leaves (Leptospermum scoparium) extracted by hydrophobic deep eutectic solvent

Manuka (Leptospermum scoparium) has been studied as a valuable shrub as its leaves are rich in bioactive components such as β-caryophyllene. This study investigated the extractability of hydrophobic deep eutectic solvent (HDES) namely menthol:lactic acid HDES for the total phenolic content (TPC) and antioxidant activity from β-caryophyllene-rich Manuka leaves. Results were also compared with ethanol and n-hexane extracts. The ethanolic extract possessed the highest amount of TPC (86.08 ± 6.22 mg GAE/g DW) among tested extracts. The extraction of TPC using HDES was at a sufficient level (79.82 ± 0.75 mg GAE/g DW), while n-hexane presented poor yield (2.74 ± 0.70 mg GAE/g DW). Higher 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and ferric reducing antioxidant power were found to be in ethanolic extract. The antibacterial effects of Manuka extract obtained by HDES was also assessed and the results were compared with the antibacterial effect of HDES, lactic acid, commercial Manuka essential oil, steam distilled Manuka oil, and β-caryophyllene pure oil. E. coli, Pseudomonas aeruginosa and Staphylococcus epidermidis were tested using agar disc diffusion method. Results revealed that lactic acid, HDES, and Manuka-HDES extract showed toxicity towards the tested bacteria indicating that the bactericidal effect of the Manuka extract was due to the lactic acid as a forming compound. This study verified the possibility of extracting and characterising different bioactive compounds from Manuka leaves using menthol:lactic acid HDES in a single step and thus it could be explored for broader industrial applications.

Chemical, physical, and functional properties of Thai indigenous brown rice flours.

Thai indigenous brown rice flours from Nakhon Si Thammarat, Thailand, namely Khai Mod Rin (KMRF) and Noui Khuea (NKRF), were assessed for quality aspects in comparison with brown Jasmine rice flour (JMRF) and commercial rice flour (CMRF) from Chai Nat 1 variety. All the rice flours had different chemical composition, physical characteristic, and techno-functionality. The KMRF, NKRF, and JMRF were classified as a low amylose type (19.56-21.25% dw). All rice flours had low total extractable phenolic content (0.1-0.3 mg GAE/g dw) with some DPPH● scavenging activity (38.87-46.77%). The variations in the bulk density (1.36-1.83 g/cm3), water absorption capacity (0.71-1.17 g/g), solubility (6.93-13.67%), oil absorption capacity (1.39-2.49 g/g), and swelling power (5.71-6.84 g/g) were noticeable. The least gelation concentration ranged from 4.0 to 8.0% where KMRF was easier to form gel than JMRF, and NKRF/CMRF. The foam capacity of the flours was relatively low (1.30-2.60%). The pasting properties differed among rice flours and the lowest pasting temperature was observed in CMRF. Overall, the chemical, physical, functional, and pasting qualities of flours were substantially influenced by rice variety. The findings offered fundamental information on Thai indigenous rice flour that can be used in food preparations for specific uses.

Antioxidant and antifungal activities of Myrianthus arboreus P. Beauv. (Moraceae), Allanblackia gabonensis Pellegr. (Clusiaceae) and three other Cameroonian medicinal plants

Background: Biological activities of medicinal plants make them attractive alternative complementary medicines. Therefore, this study aimed to assess the antioxidant and antifungal activities of the methanol extract of Myrianthus arboreus, Allanblackia gabonensis, Gladiolus quartinianus, Peperomia fernandopoiana and Vepris soyauxii. Methods: Total phenolic contents (TPC) and flavonoid contents (FC) were evaluated using standard methods. The antioxidant activity of the extracts was determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and ferric reducing power assays. Antifungal activity was evaluated by the broth micro-dilution method. Results: TPC of extracts ranging from 67.89 to 196.01 mgGAE/g TPC were very higher in P. fernandopoiana whole plant (PFW) extract (196.01±10.25 mgGAE/g) and MAL (165.71±10.68 mgGAE/g) whereas the A. gabonensis fruit extract (AGF) and M. arboreus bark extract (MAB) had the highest flavonoid content (66.54 ± 2.12 and 48.13 ± 1.65 mgEC/g of extract, respectively). Apart from M. arboreus leave extract (MAL), all extracts showed important DPPH radical scavenging activity (IC50 < 20 μg/mL). AGFl and PFW exhibited significant ferric reducing power compared to ascorbic acid and other extracts (P<0.05). Each of the tested extracts showed antifungal activity against atleast one of the five pathogenic fungi, with MICs ranging from 128 to 1024 µg/mL. MAL was active on all the tested fungi whereas MAB showed the highest antifungal activity (MIC=128 µg/mL). Conclusion: The findings of this study emphasize the evidence that the methanol extracts of the leave and bark of Myrianthus arboreus could be an alternative to fight against oxidative stresses and infections due to opportunistic yeast pathogens. Keywords: Oxidative stress; fungal infection; medicinal plant; antioxidant activity; antifungal activity.

Phytochemical and antioxidant activity of Cadaba farinosa Forssk stem bark extracts

Abstract Cadaba farinosa is used in traditional medicine for treatment of cancer, diabetes, and rheumatism. The research was aimed at evaluating the phytochemical and antioxidant activity of the extracts. The powdered stem bark was extracted successively with the aid of Soxhlet extractor using n-hexane, ethyl acetate, and methanol. The resulting extracts were concentrated on rotary evaporator and the percentage yields were calculated. The phytochemical and TLC profiles of the extracts were studied. The antioxidant activity of the extracts and ascorbic acid (standard) were determined using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical assay. The total phenolic content of the extracts and tannic acid (standard) were evaluated using Folin–Ciocalteu reagent. The percentage yields of n-hexane, ethyl acetate, and methanol extracts were found to be 1.19, 1.37, and 13.93%, respectively. The phytochemical screening revealed the presence of tannins, flavonoids, saponins, cardiac glycosides, alkaloids, and triterpenoids. The TLC profiles of the extracts revealed the presence of compounds as evidenced from their R f values. The total phenolic content of ethyl acetate and methanol extracts were found to be 135 and 112 mg, respectively. The free radical scavenging activity demonstrated by the extracts was comparable to ascorbic acid. The ethyl acetate extract had higher phenolic content and demonstrated the highest free radical scavenging with IC50 31.07 mg/mL. The results of research have provided strong preliminary evidence of antioxidant activity which may be because of phenolic compounds in the extracts.

How Quantity of Bioactive Compounds of Zataria multiflora Differ Using Traditional or Modern Extraction Methods

For obtaining bioactive compounds, decoction of Zataria multiflora (ZM) plant materials was interactively evaluated and compared with the modern method of ultrasound-assisted extraction (UAE). The interactive effects of several parameters including; liquid to solid (L/S) ratio, extraction time, extraction method, and plant material size were studied and optimized using the response surface methodology (RSM). Interpretation of the model outputs revealed that total phenolic content (TPC) of the resulting extracts is mostly affected by the interactive effect of plant material size and the extraction time, while rosmarinic acid (RA) content is only affected by the extraction method. Decoctions was found to have higher RA content (21.19 (mg/g E)) in comparison to UAE extractions (11.64 (mg/g E)), statistically significant at (p ≤ 0.05). In addition, UAE as the modern method of extraction showed no privilege over the conventional method in the case of RA and TPC extraction. However, results suggest higher efficiency of UAE compared to decoction for extraction of antioxidant compounds by water. Eventually, ZM decoction obtained by the optimal extraction conditions was chemically characterized for the first time by the aid of LC-MS/MS chromatography. Naringenin, which is almost exclusively found in Citrus fruits, besides luteolin-7-O-rutinoside and a natural derivative of citric acid were shown to be the major constituents of ZM decoction.

Kinetics of extraction of total phenolic content from Sesbania grandiflora L. leaves using ultrasound

ABSTRACT The ultrasound-assisted extraction of Total Phenolic Content from Sesbania grandiflora L. leaves and its optimization with kinetics is dealt with in this study. The effect of extraction of solvents (ethanol–water composition), solid to solvent ratio (1:10–1:70), particle size (0.1–0.5x 10−3m), power (50–120 W), and extraction temperature (30–50°C) on total phenolic content (TPC) from Sesbania grandiflora leaf powder has been investigated. The overall optimized parameters for the ultrasound-assisted extraction of Total Phenolic Content from Sesbania grandiflora L. leaves are solid to solvent ratio of 1:50, particle size of 0.4–0.5 × 10−3m, power 120 W, extraction temperature 45°C with the maximum phenolic content of 14.37 × 10−3g GA/g. Comparatively, equilibration time of UAE (240 s) is very low than the conventional batch operation (960 s). A semi-empirical two parameter, Peleg’s model, assists in capturing the reaction kinetics where it elucidates the experimental behavior in a precise way.

Statistical evaluation of main extraction parameters in twenty plant extracts for obtaining their optimum total phenolic content and its relation to antioxidant and antibacterial activities.

The main extraction parameters were statistically evaluated for 20 medicinal plants to obtain the optimum conditions for maximum extraction of total phenolic content (TPC) in each plant. Among various extraction parameters, pH, temperature, and concentration at different levels were studied. The results were analyzed using the analysis of variance to achieve the optimum conditions of phenolic extraction for all plants. Also, investigation of the optimum antioxidant (AnOX) activities using DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) method and antibacterial potential against common pathogenic bacteria of Staphylococcus aureus, Escherichia coli, Pseudomonas spp., and Candida spp. through disk diffusion method for the extract of all plants under the optimum total phenolic concentration of each plant extract confirmed a direct relation among bioactivity and TPC.

Impact of the use of pressurized liquids on the extraction and functionality of proteins and bioactives from brewer’s spent grain

A green methodology based on pressurized liquids (PLE) to extract proteins and obtain highly active extracts from brewer’s spent grain (BSG) is proposed. Box-Behnken experimental design was employed to study the effect of extraction parameters on the protein content (PC), the total phenolic content (TPC), and the antioxidant activity of extracts. Results were compared with those obtained by conventional alkaline extraction assisted with ultrasounds (UAE). The selection of PLE conditions enabled to tailor the PC and TPC of extracts. PLE extracted 36 % more proteins than UAE. PLE extracts showed higher antioxidant, cholesterol esterase inhibition, and ACE inhibitory activities than UAE extract. HPLC-MS/MS enabled to observe that the extraction technique and experimental conditions significantly affected to the kind and amount of extracted proteins, and released peptides, and phenolic compounds. A higher ratio of hydrophobic peptides was observed in PLE extracts, which justified their higher bioactivity.

Phytochemical Analysis, Antioxidant and Anticancer Potential of Sideritis niveotomentosa: Endemic Wild Species of Turkey.

Sideritis niveotomentosa Hub. -Mor. is a local endemic species belonging to the Lamiaceae family. In this study, GC/MS analysis, total antioxidant capacity and anticancer effects of different extracts obtained from S. niveotomentosa were investigated comparatively. Total phenolic contents of extracts were determined by the Folin–Ciocalteu method, total flavonoid contents by aluminum chloride method, and also the free radical scavenging activities of the extracts by DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) assay. The cytotoxic effect of the extracts was studied via MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) assay on DLD1, HL60 and ARH77 cell lines. Pro-apoptotic gene expression levels were also tested in the most sensitive cell line ARH77 by Real-Time PCR. The expression levels of 4 pro-apoptotic genes, APAF, BAX, CASP3, and HRK were found to be upregulated in ARH77 cells that were treated extracts. Results showed that methanolic extracts contain more phenolic content than acetone extracts, consistent with DPPH results. As a result, Sideritis niveotomentosa extracts, especially methanolic extracts, are rich in phenolic content and have a strong radical scavenging effect. In addition, the extracts showed selective effects on cell lines. This study is pioneering in terms of future studies, and the findings provide hope for future experimentation.

Total phenolic content, antioxidant, anti-inflammatory and anti-microbial potentials of Bambara groundnut (Vigna subterranea L.) seed extract

PurposeBambara groundnut is a hard-to-cook grain and this has limited its utilisation to some extent. However, the grain is a good source of phytochemicals with antioxidant properties. This study investigated the total phenol content, antioxidant, anti-inflammatory and anti-microbial potentials of hot-water extract of four Bambara groundnuts differentiated by their seed coats (cream, black, maroon and brown).Design/methodology/approachBambara grains were heated in water at a ratio 1:20 (w/v) and the grains brought to boiling in a controlled water bath. As soon as boiling started, the temperature was reduced to 90 °C to reduce the evaporation rate. The extracts were withdrawn within 30 min, which was chosen from a preliminary study where beyond this time, the extract was drying off and the amount of solution obtained was not sufficient for the initial run. Grain colour and composition and antioxidant, antimicrobial and anti-inflammatory properties of the extract were determined using standard methods.FindingsProtein (20.57–26.31%) and carbohydrate (55.43–61.09%) were the major components of the grain. Grain type and boiling time generally affected the total phenolic content of the extract. Cream Bambara displayed substantially lower total phenolic content at all boiling times compared with the maroon, brown and black Bambara groundnuts. The total flavonoid contents and total phenolic contents of the Bambara groundnut extracts were dependent on the boiling time and type of grain. The extracts showed no activity against Candida albicans, but the maroon coat Bambara demonstrated a peak inhibition of 6.00 mm against Escherichia coli. The total phenolic, flavonoid contents and the antioxidant properties of the grains generally followed the order Maroon > Black > Brown.Originality/valueThis study has demonstrated the possibility of promoting the use of Bambara groundnut beyond the current level of usage by using simple processing method of boiling to extract phytochemicals with medicinal properties.

Application of Response Surface Methodology for optimization ofbivalent extraction from Pomegranate Peel

ABSTRACT In present study, an ideal bivalent extraction system was selected and optimized for phenolic extraction of pomegranate peel .Study reported ethanol: ether bivalent solvent system with phenolic content having potent antioxidant activity. Selected bivalent system was optimized for extraction using response surface methodology (RSM). A Box–Behnken design was employed to analyze the effects of variables (temperature, time and peel concentration) on the extraction of total phenolic content, and antioxidant capacity (FRAP). The optimization study suggested extraction with 2.9% pomegranate peel for 8 hours at 40 OC was found the best for extraction of phenolic compound with potent antioxidant activity. RSM was shown to be an adequate approach for modeling the extraction of phenolic compounds from pomegranate peel.The pomegranate peel was extracted using optimized parameters and extract was concentrated in rotary vacuum evaporator at 45 oC for 6 hours. The concentrated extract was used to formulate antioxidant enriched ice cream product. The ice–cream formulation containing 1% of peel extract was found to be more acceptable in terms of sensory parameters. Proximate analysis of acceptable formulation reveals 3.54% protein, 3.51% fat, 22.24% carbohydrate, 0.83% ash, and 69.88% moisture, however62.871 DPPH % inhibition and 84.96 mg/100ml of AAE, FRAP activity and 363.266 mg/100 ml of GAE phenolic content was also reported with ice cream enriched with 1%peel extract Results shown the antioxidant enriched ice cream could be formulated using extract of pomegranate peel powder with good sensory properties.

Antioxidant Properties and Total Phenolic Contents of Extracts from Three Macroalgae Collected from Chabahar Coasts

Antioxidant Properties and Total Phenolic Contents of Extracts from Three Macroalgae Collected from Chabahar Coasts

Flavonoids from aerial part of Algerian Ajuga iva (L.) schreb.: The HPLC-UV analysis and Antioxidant capacity

The study deals with the evaluation of the antioxidant capacity of extracts from the aerial part of Algerian Ajuga iva. Extraction of flavonoids was carried out by 85% of methanol, then the crude extract was successively separated with ethyl acetate, butanol, and water. The in vitro antioxidant activity was assessed by 1,1-diphenyl-2-picrylhydrazyl, reducing power, and thiobarbituric acid reacting substances assays. Extracts are subject to HPLC-UV analysis. The average total phenol contents of extracts vary between 3.87 ± 0.17 and 149.74 ± 3.94 (gallic acid equivalent per gram of dry extract). Furthermore, tested extracts exhibited a broad range of flavonoid contents varying from 1.54 ± 0.09 to 41.18 ± 1.03 (catechin equivalent per gram of dry extract). Butanol and ethyl acetate fractions displayed the highest antioxidant activity. A good correlation between the phenolic and flavonoid contents and the antioxidant activity was observed. Rutin, caffeic acid, quercetin, p-coumaric acid, luteolin, and cinnamic acid were present in the extracts. The plant could be a potential source of antioxidant agents.

Simultaneous determination of five bioactive constituents in fruit rind extracts of Garcinia lanceifolia using a validated UHPLC-PDA method and evaluation of antioxidant activity

Xanthones and polyisoprenylated benzophenones found in Garcinia species are groups of secondary metabolites with a wide range of bioactivities. Three xanthones namely α-mangostin, β-mangostin, γ-mangostin and two polyisoprenylated benzophenone namely xanthochymol and isoxanthochymol were identified and quantified in the extracts prepared from fruit rinds of G. lanceifolia using a validated UHPLC-PDA method. Total phenolic content of extracts prepared from G. lanceifolia fruit rinds with solvents of varying polarity was determined by the Folin-Ciocalteu method. These extracts were also evaluated for their antioxidant potential using three different in vitro assays namely DPPH free radical, ABTS cation radical and reducing power. α-mangostin was not quantified in hexane and chloroform extracts. β-mangostin could not get quantified in hexane extract. γ-mangostin was not detected in any of the six extracts. The maximum content of xanthochymol (289.26 ± 0.31 mg/g) was detected in hexane extract. Isoxanthochymol content (9.91 ± 0.01 mg/g) was maximum in hexane extract and it was followed by chloroform extract (2.67 ± 0.01 mg/g). The highest total phenolic content was recorded for hexane extract (18.60 ± 1.95 mg/g GAE). In vitro assays established that G. lanceifolia extracts exhibited significant antioxidant activity.

Phenolic Compounds, Antioxidant Activity and Fatty Acid Composition of Roasted Alyanak Apricot Kernel.

The oil recovery from Alyanak apricot kernel was 36.65% in control (unroasted) and increased to 43.77% in microwave-roasted kernels. The total phenolic contents in extracts from apricot kernel were between 0.06 (oven-roasted) and 0.20 mg GAE/100 g (microwave-roasted) while the antioxidant activity varied between 2.55 (oven-roasted) and 19.34% (microwave-roasted). Gallic acid, 3,4-dihydroxybenzoic acid, (+)-catechin and 1,2-dihydroxybenzene were detected as the key phenolic constituents in apricot kernels. Gallic acid contents varied between 0.53 (control) and 1.10 mg/100 g (microwave-roasted) and 3,4-dihydroxybenzoic acid contents were between 0.10 (control) and 0.35 mg/100 g (microwave-roasted). Among apricot oil fatty acids, palmitic acid contents ranged from 4.38 (oven-roasted) to 4.76% (microwave-roasted); oleic acid contents were between 65.73% (oven-roasted) and 66.15% (control) and linoleic acid contents varied between 26.55 (control) and 27.12% (oven-roasted).

Free radical scavenging potential and antibacterial activity of <em>Cola nitida and Garcinia kola</em> extracts against bacterial strains isolated from patients with urinary tract infections

Cola nitida and Garcinia kola are found and widely consumed in West Africa. The seeds of these plants have various traditional uses and are reported to exhibit several bioactivities. Their phytochemical, antioxidant and antibacterial properties of methanol, ethanol and aqueous extracts were investigated in the present study. Phytochemical screening and quantification of total phenolic contents analysis were carried out for phytochemical investigation. Preliminary phytochemical screening revealed the presence of flavonoids, alkaloids, tannins, saponins, protein and glycosides in the seed extracts. Quantitative phytochemical constituents revealed 0.818 ± 0.021and 0.700 ± 0.017mg of phenolic compounds and total flavonoid content of 25.63 ± 1.60 and 25.10 ± 1.85mg in G. kola and C. nitida respectively. The extracts showed potent antioxidant activities compared to standard antioxidants by significantly inhibiting 2, 2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl radical (∙OH), and superoxide anion radicals (O2∙) dose dependently. The methanol extracts of G. kola and C. nitida showed significant inhibitory action (p<0.05) against the bacterial isolates. The minimum inhibitory concentration obtained for methanol extract of the plants and both the mixture was 12mm at 31.25mg/ml for Klebsiella pneumoniae while the ethanol and aqueous extract of the plants and both the mixture was 13mm and 12.33mm at 31.25mg/ml and 125mg/ml respectively for E. coli. A direct correlation was observed between total phenolic content of extracts and radical scavenging potential, thus linking the observed bioactivities of these extracts to the presence of the phytochemical. The mixture of these seed extracts showed greater effect against the bacterial isolates, therefore providing a platform for advance studies in the development of drugs against infectious diseases. Key words: Agar well dilution, antibacterial activity, Cola nitida, Garcinia kola, Free radical scavenging potential

Identification of Phlorotannins in the Brown Algae, Saccharina latissima and Ascophyllum nodosum by Ultra-High-Performance Liquid Chromatography Coupled to High-Resolution Tandem Mass Spectrometry.

Phlorotannins are bioactive polyphenols in brown macroalgae that make these algae interesting as healthy food. Specific phlorotannins are, however, seldom identified, and extracts from different species are often only analysed for total phenolic content (TPC). In this study, our focus was to identify phlorotannin molecules from Saccharina latissima and Ascophyllum nodosum (a species rich in these compounds) using ultra-high-performance liquid chromatography coupled to high-resolution tandem mass spectrometry (UHPLC-HRMS2). Water and ethanol (30 and 80% v/v) were used at solid:liquid ratios, extraction times and temperatures, proposed to result in high TPC in extracts from other species. The S. latissima extracts, however, did not allow phlorotannin detection by either UHPLC-UV/Vis or UHPLC-HRMS2, despite a TPC response by the Folin–Ciocalteu assay, pinpointing a problem with interference by non-phenolic compounds. Purification by solid phase extraction (SPE) led to purer, more concentrated fractions and identification of four phlorotannin species in A. nodosum and one in S. latissima by UHPLC-HRMS2, using extracts in ethanol 80% v/v at a solid:liquid ratio of 1:10 for 20 h at 25 °C with an added 10 h at 65 °C incubation of remaining solids. The phlorotannin with the formula C12H10O7 (corresponding to bifuhalol) is the first identified in S. latissima.

Identification of Phenolic Compounds and Determination of Antioxidant Activity in Extracts and Infusions of Salvia Leaves.

The influence of harvest period and drying method of Salvia officinalis L. leaves on the content of essential oils, polyphenols and antioxidant properties was investigated. Sage leaves were collected twice during plant blossoming (in June and July) and dried traditionally in natural conditions and at 35 °C. Antioxidant activity was assayed in methanol-acetone extracts and infusions of dried leaves with the use of free radical scavenging activity (DPPH) and ferric reducing antioxidant power (FRAP) technique. Total phenolic content in extracts as well as in infusions was determined by the means of Folin–Ciocalteu method. Based on the LC/MS analysis, the polyphenol compounds present in both extracts and in infusions were identified. The extracts contained more polyphenols and were characterized by higher antioxidant activity than infusions. In the extracts significant amount of ferulic acid was found, which was influenced both by the harvest period and drying method. The amount of ferulic acid found in extracts obtained from the June leaves dried traditionally was three times lower (6.185 μg/g DW) than in extracts from July leaves dried in the same conditions. Harvest period had a significant effect on the essential oils’ content, leaves collected in July contained 15% more oils than those collected in June.

Evaluation of chemical composition, trace element content, antioxidant and antimicrobial activities of Verbascum pseudoholotrichum

Given that some Verbascum species are effective against influenza viruses, an endemic species, Verbascum pseudoholotrichum is thought to have the potential to be used in the treatment of virucidal diseases. It was extensively investigated for its antioxidant and antimicrobial activities, chemical and trace element composition. The soxhlet extraction method was applied in the extraction process of the above-ground parts of the plant using three solvents (methanol, ethanol and water). The total phenolic content of extracts was between 175.7 and 186.1 mg GAE/100 g on the dried weight basis. DPPH radical scavenging activity analysis was performed and IC50 values were 0.539–1.254 mg mL−1. In total, 38 compounds were detected by GC–MS analysis. ICP-MS analysis was applied to identify the total contents of 24 elements in dried samples. The antimicrobial activity of the extracts was evaluated on six different pathogens using the spectrophotometric microdilution technique. The obtained minimum inhibitory concentration values were 17.37 µ–113.9 µg mL−1 at the end of the 24-h incubation. The highest and lowest inhibition zones were 5.0 and 0.3 mm for ethanol extract against Bacillus subtilis and water extract against Enterococcus fecalis, respectively, and no resistance was seen against Escherichia coli using disc diffusion method.

Subcritical water extraction of phenolics, antioxidants and dietary fibres from waste date pits

The growing demand for dates, as food, has enhanced its production and increased the total amount of date pits waste. Subcritical water extraction (SCWE) can be used to effectively extract valuable products from date pits. This study was to extract phenolic compounds, total flavonoid content, antioxidants, and dietary fibres from the date seeds using SCWE. The effects of process variables such as feed mixture concentration (x), extraction temperature (T), and extraction time (t) on the yields of total phenolic content (TPC), total flavonoid content (TFC), antioxidants, and dietary fibres were investigated for process optimisation using desirability approach. The results showed that extraction temperature could significantly increase TPC, TFC, and dietary fibres extraction yields, but has less effect on the antioxidant extraction. The feed mixture concentration has shown a significant effect on antioxidant extraction but was insignificant on TPC, TFC, and dietary fibres extractions. The desirability approach of process optimisation validated the feasibility of using SCWE for valuable products extraction from date pits.