The objective of the study was to determine and compare the effect of several solvents namely hot water, 50 % methanol, ethanol, 50 % ethanol, acetone, 50 % acetone and ethyl acetate on phenolic composition and free radical scavenging activity in black tea and selected herbal infusions from Zimbabwe and Brazil. For the black tea, made from Camellia sinensis, Quickbrew™ was used. Zimbabwean herbal infusions used were Lippia javanica and Ficus sycamore while those from Brazil were Syzygium jambolanum, Cuphea carthagenensis and Ilex paraguariensis. Total phenolic content and free radical scavenging activity were determined using Folin-Ciocalteu and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, respectively. IC50 values for each solvent were calculated and used to interpret radical scavenging activity. Aqueous organic solvents extracted higher quantities of phenolic compounds than in their absolute organic nature. Acetone (50 %) extracted a higher total phenolic content (TPC) in C. sinensis, L. javanica and I. paraguariensis. Hot water extracted the highest TPC in F. sycamore and S. jambolanum while 50 % ethanol was highest in C. carthagenensis. Free radical scavenging activity (FRSA) was not necessarily in the same order as TPC, indicating that high TPC does not always mean high FRSA and vice versa. The highest FRSA for S. jambolanum and C. carthagenensis extracts was in 50 % ethanol, F. sycamore in 50 % methanol, and I. paraguariensis, C. sinensis and L. javanica extracts in 50 % acetone. Ethyl acetate recorded the lowest TPC and FRSA in all plant samples analysed. Generally, solvent used affected TPC and free radical scavenging activity. Organic solvents may need to be separated from phenolics after extraction, as some of them namely acetone, methanol and ethyl acetate can be toxic to humans. Water and ethanol are the least toxic solvents which may need no further separation from extracts.

Effect of Solvent Type on Total Phenolic Content and Free Radical Scavenging Activity of Black Tea and Herbal Infusions

Macadamia is well known for its high-quality kernel; however, its skin and husk, known as waste, have had limited uses as by-products. This study aimed to determine the characteristics of the macadamia nut and to examine the impact of different solvents on the recovery of phenolic compounds (TPC), flavonoids, proanthocyanidins and antioxidant properties of the macadamia skin. The results showed that the kernel, the commercial part, only accounts for about 20% of the nut weight; whereas, the skin or the husk, the waste, account for approximately 40%, revealing that macadamia skin is an abundant starting material for the utilisation of by-products. The type of solvents was found to significantly affect the recovery yields of bioactive compounds from the macadamia skin. The combination of organic solvents, methanol, ethanol, acetonitrile and acetone with water (50%, v/v) had the highest recovery yields for TPC, flavonoids and proanthocyanidins as well as the most potent antioxidant properties, follow...

https://www.tandfonline.com/doi/pdf/10.1080/23311932.2015.1115646

Effect of extraction solvents on recovery of bioactive compounds and antioxidant properties from macadamia (Macadamia tetraphylla) skin waste

Present study was designed to compared the total flavonoids and polyphenols contents and antibacterial activity of hawthorn extracts with different polarities as well as the underlying antibacterial mechanisms. The results showed that among all hawthorn extracts, methanol and ethanol extracts (ME and EE) exhibited high levels of total flavonoids and polyphenols contents, followed by acetone, ethyl acetate, trichloromethane and petroleum ether extracts. ME exhibited the strongest antibacterial activity against tested bacteria, especially Staphylococcus aureus with a 1.25 μg/mL of the minimum inhibitory concentration (MIC) and minimum bactericide concentration (MBC). Further analysis revealed that the main phenolic compounds from ME were epicatechin (281.6 mg/100 g DW), procyanidin B2 (243.5 mg/100 g DW), chlorogenic acid (84.2 mg/100 g DW) and quercetin (78.4 mg/100 g DW). The action mechanism of ME against S. aureus could be ascribed to ME damaging cell wall and cell membrane integrity, inhibiting intracellular enzyme activity, increasing reactive oxygen species (ROS), also changing expression of associated genes and then inducing apoptosis of S. aureus. In addition, the antimicrobial activity of ME against S. aureus has also been demonstrated to be efficient in the food matrix (whole milk).

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Chemical composition, antibacterial activity and action mechanism of different extracts from hawthorn (Crataegus pinnatifida Bge.).

Chamomile has been used as an herbal medication since ancient times and is still popular because it contains various bioactive phytochemicals that could provide therapeutic effects. In this study, a simple and reliable HPLC method was developed to evaluate the quality consistency of nineteen chamomile samples through establishing a chromatographic fingerprint, quantification of phenolic compounds and determination of antioxidant activity. For fingerprint analysis, 12 peaks were selected as the common peaks to evaluate the similarities of commercial samples of chamomile obtained from different manufacturers. A similarity analysis was performed to assess the similarity/dissimilarity of chamomile samples where values varied from 0.868 to 0.990 what indicating that samples from different manufacturers were consistent. Additionally, simultaneous quantification of five phenolic acids (gallic, caffeic, syringic, p-coumaric, ferulic) and four flavonoids (rutin, myricetin, quercetin and keampferol) was performed to interpret the quality consistency. In quantitative analysis, the nine individual phenolic compounds showed good regression (r > 0.9975). Inter- and intra-day precisions for all analysed compounds expressed as relative standard deviation (CV) ranged from 0.05% to 3.12%. Since flavonoids and other polyphenols are commonly recognised as natural antioxidants, the antioxidant activity of chamomile samples was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and ferric reducing/antioxidant power (FRAP) assay. Correlation analysis was used to assess the relationship between antioxidant activity and phenolic composition, and multivariate analysis (PCA and HCA) were applied to distinguish chamomile samples. Results shown in the study indicate high similarity of chamomile samples among them, widely spread in the market and commonly used by people as infusions or teas, as well as that there were no statistically significant differences among them, which in turn is a proof of high quality of commercially available samples of chamomile. The study indicated that the combination of chromatographic fingerprint and quantitative analysis can be readily utilised as a quality consistency method for chamomile and related medicinal preparations. Moreover, the applied strategy seems to be the most promising for the assessment of the investigated plant material.

An Approach Based on HPLC-Fingerprint and Chemometrics to Quality Consistency Evaluation of Matricaria chamomilla L. Commercial Samples.

Mushrooms are rich in pharmacologically-important phytochemicals with reported medicinal values. In this study, the antibacterial activity of Flammulina velutipes (Enoki), Hypsizygus tessellatus (brown (Buna shimeji) and white (Bunapi shimeji) variants) stem extracts prepared with different solvents (water, methanol, acetone, and ethyl acetate) was investigated against Escherichia coli (E. coli ATCC 25922), Serratia marscenscens (S. marscenscens ATCC14756), Bacillus subtilis (B. subtilis ATCC 23857), and Staphylococcus aureus (S. aureus ATCC 25923). Their antioxidant activities were evaluated using radical scavenging assays of 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydrogen peroxide (H2O2) and ferric reducing power (FRP). The water extracts of Enoki, Buna shimeji, and Bunapi shimeji showed bacterial growth inhibition in a concentration-dependent manner. From the obtained results, all the Enoki extracts showed a significant inhibition of the gram positive bacterial species (E. coli and S. marcescens > 68%) and a reduced inhibition of the gram negative bacterial species (B. subtilis and S. aureus < 45%, p < 0.05) after 24 h of incubation, while water extracts of Buna shimeji showed a significantly lower bacterial growth inhibition (< 60%) against all the studied bacteria. Bunapi shimeji extract inhibited S. marscenscens, E. coli, B. subtilis, and S. aureus by 54, 67, 46, and 44%, respectively. Methanol, acetone and ethyl acetate extracts showed significantly lower antibacterial activities (p < 0.05) compared to water extracts. Similarly, water extracts of Enoki, Bunapi shimeji and Buna shimeji showed significant antioxidant activities using DPPH (67.37 ± 0.01, 66.30 ± 0.18 and 42.44 ± 0.18%, respectively), hydrogen peroxide (67.87 ± 0.000, 45.52 ± 0.160 and 52.08 ± 0.000% respectively), and FRP (0.891 ± 0.001, 0.413 ± 0.001 and 0.491 ± 0.001, respectively) at the concentration of 1 mg/mL, compared to their respective methanol, acetone and ethyl acetate fractions. Upon LC-MS analysis of the most potent fraction (Enoki water extract), several phenolic compounds were identified, of which chromogenic acid, Methyl-5-O-caffeoylquinate, Kukoamine A, Kushenol K, Methyl Kushenol C, Glabrol, Sanggenon J, Corylin, and Moracenin C were confirmed. The antioxidant activities of the water extracts of Enoki, Buna shimeji and Bunapi shimeji correlated with their total phenolic and flavonoid contents, which were (166.56 ± 1.50, 108.13 ± 0.32 and 116.71 ± 0.01 µg gallic acid equivalent (GAE)/mg, respectively) and (96.33 ± 0.03, 82.18 ± 0.20 and 91.37 ± 0.15 µg quercetin equivalent (QE)/mg, respectively). Collectively, the study results have shown the studied mushrooms as potential natural sources of pharmacological agents.

Evaluation of antioxidant and antibacterial activities of the stems of Flammulina velutipes and Hypsizygus tessellatus (white and brown var.) extracted with different solvents.

In this study, three types of solvent extracts from two cultivars of papaya fruit (Hongkong and Eksotika) were used to examine the effects of extraction solvent on total phenolics content (TPC), total flavonoids content (TFC) and antioxidant activity by ferric reducing antioxidant power (FRAP), 1,1-diphenyl-2-picryl hydrazyl radical scavenging (DPPH) and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) were determined spectrophotometrically Results showed that extraction solvent had significant effects on TPC, TFC, and antioxidant activity of methanol and acetone extract The highest content of TPC, TFC and antioxidant activity (FRAP, DPPH and ABTS) were found in 50% methanol and 50% acetone extracts The TPC varied for both cultivars (Hongkong and Eksotika) from 1635 to 4665, 6750 to 2338 mg gallic acid/100 g fresh weight, and TFC were between 1940 and 3617, 3981 and 2104 mg quercetin/100 g fresh weight and antioxidant activity (FRAP from 12484 to 9023, 19059 to 15998 mg Trolox equivalents/100 g fresh weight), DPPH were between 4782 and 2872%, 7456 and 3857%) and (ABTS from 5734 to 3149% and 6906 to 3484%), respectively The largest amount of TPC and TFC which leads to more effective radical scavenging effect was shown by 50% methanol extract Moreover, amount of phenolic compounds and antioxidant activities increased in methanol and acetone extract Therefore, a positive correlation occurred between antioxidant activity and phenolics compound Methanol 50% and acetone 50% solvent showed the greatest capability in extracting antioxidants and inhibiting the free radicals produced It was concluded that extraction solvent play important roles on the phenolics compounds and their antioxidant activity of papaya fruit extract

	 

	Key words: Papaya, extraction solvent, antioxidant activity, phenolic compound

https://www.academicjournals.org/article/article1386586217_Addai et al.pdf

Effect of extraction solvents on the phenolic content and antioxidant properties of two papaya cultivars

ABSTRAK Kajian ini dijalankan untuk mengesahkan kemampuan teknologi DNA mikroaturan cip gen Olipro TM FoodPATH bagi mengesan bakteria patogen makanan. Sebanyak 9 jenis DNA bakteria patogen makanan telah digunakan iaitu Bacillus cereus, Escherichia coli O157:H7, Staphylococcus aureus, Vibrio cholerae, Vibrio parahaemolyticus, Listeria monocytogenes, Salmonella spp., Shigella spp. dan Campylobacter spp. Sebanyak 36 kombinasi templat DNA bakteria patogen makanan telah digunakan. Pengesahan bagi mengesan bakteria patogen makanan dilakukan dengan menggunakan kaedah reaksi berantai polimerase (PCR) dan penghibridan Southern-blotting di atas cip gen untuk mengesahkan kemampuannya. Keputusan daripada analisis hibridasi di atas cip gen telah dibandingkan dengan hasil gel elektroforesis 2.0% (w/v). Lima saringan diperlukan untuk menghabiskan 36 kombinasi templat DNA bakteria patogen makanan. Setiap saringan, satu cip gen telah digunakan sebagai kawalan negatif tidak diinokulasikan dengan sebarang kombinasi DNA bakteria patogen makanan. Daripada hasil kajian, didapati bahawa semua kombinasi templat DNA bakteria patogen makanan telah dapat dikesan. Cip yang digunakan sebagai kawalan negatif tidak menunjukkan kehadiran DNA. Oleh itu, daripada kajian ini cip gen Olipro TM FoodPATH didapati memberikan keputusan yang lebih baik berbanding dengan 2.0% (w/v)

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Pengesahan bagi Mengesan Bakteria Patogen Makanan Menggunakan Teknologi Mikroaturan DNA (Validation of Food-borne Pathogen Detection using DNA Microarray Technology)

Sahilah Abd

Papers

Effect of extraction solvents on the phenolic content and antioxidant properties of two papaya cultivars

Pengesahan bagi Mengesan Bakteria Patogen Makanan Menggunakan Teknologi Mikroaturan DNA (Validation of Food-borne Pathogen Detection using DNA Microarray Technology)