Ultrasound-Assisted Extraction of Phenolic Compounds from Alpinia galanga (L.) Willd. rhizome

In this study, the main purpose is to determine the ultrasound-assisted extraction (UAE) conditions for extracting phenolic compounds obtained from Alpinia galanga (L.) Willd. rhizome. The influences of extraction factors (type of solvent, solvent concentration, solid[1]to-liquid (SL) ratio, time and temperature) on the total polyphenol content (TPC) and 2,2-diphenyl-1-picrylhydrazyl free radical scavenging capacity (DPPHRSC) were investigated. The findings pointed out that all of these factors significantly affected TPC and DPPHRSC. The highest TPC and DPPHRSC obtained from A. galanga root extract were 7.49 ± 0.19 mg GAE g-1 DM and 90.34 % at the acetone concentration of 60 % (v/v), SL ratio of 1:25, extraction time of 20 min and extraction temperature of 40oC. The microstructure of the sample before and after extraction significantly changed under ultrasound radiation

Ultrasound-Assisted Extraction of Phenolic Compounds from Alpinia galanga (L.) Willd. rhizome

In this study, the main purpose is to determine the ultrasound-assisted extraction (UAE) conditions for extracting phenolic compounds obtained from Alpinia galanga (L.) Willd. rhizome. The influences of extraction factors (type of solvent, solvent concentration, solid[1]to-liquid (SL) ratio, time and temperature) on the total polyphenol content (TPC) and 2,2-diphenyl-1-picrylhydrazyl free radical scavenging capacity (DPPHRSC) were investigated. The findings pointed out that all of these factors significantly affected TPC and DPPHRSC. The highest TPC and DPPHRSC obtained from A. galanga root extract were 7.49 ± 0.19 mg GAE g-1 DM and 90.34 % at the acetone concentration of 60 % (v/v), SL ratio of 1:25, extraction time of 20 min and extraction temperature of 40oC. The microstructure of the sample before and after extraction significantly changed under ultrasound radiation

Microwave-Assisted Extraction of Pectin from Passion Fruit Peels under Alkaline Conditions

In this study, microwave-assisted extraction (MAE) of pectin from passion fruit (Passiflora edulis Sims) peels has been investigated together with the alkaline extraction conditions such as NaOH concentration (60-220 mM), solid-to-liquid (SL) ratio (1:20-1:40, g/mL), extraction time (3-11 min), and microwave power (167-502 W) on the yield of crude pectin, purity, and degree of esterification (DE) of pectin. The results indicated that all these factors significantly affected the extraction efficiency and purity of recovered pectin. The best extraction condition was found to be as follows: NaOH concentration of 180 mM, SL ratio of 1:35 g/mL, extraction time of 7 min, and microwave power of 376 W. Under these conditions, the experimental crude pectin yield, purity, and DE value were 14.2%, 87.4%, and 92.6%, respectively. The pectin obtained was considered as high-methoxyl pectin (HMP) and the microstructure of initial peels powder completely changed under microwave heating

Physicochemical Properties and Antibacterial Activity of Essential Oil of Ageratum conyzoides L. Leaves

Essential oil (EO) of Ageratum conyzoides L. leaves was analyzed by gas chromatography – mass spectrometry (GC-MS) method. Physicochemical properties (acid value, saponification value, ester value, density and freezing point), antioxidant capacity and antibacterial capacity were determined. In general, 34 compounds were identified in EO of this material. Moreover, EO has the antioxidant capacity, and the antimicrobial activity was determined by the paper disc diffusion method for antibiotic susceptibility testing. Essential oil does not affect the growth of Staphylococcus aureus - ATCC 25923, Bacillus subtilis - ATCC 11774 and Escherichia coli - ATCC 25922. However, the result also shows that EO of A. conyzoides leaves can inhibit the growth of Salmonella enteritidis - ATCC 13076

Physicochemical Properties and Antibacterial Activity of Essential Oil of Ageratum conyzoides L. Leaves

Essential oil (EO) of Ageratum conyzoides L. leaves was analyzed by gas chromatography – mass spectrometry (GC-MS) method. Physicochemical properties (acid value, saponification value, ester value, density and freezing point), antioxidant capacity and antibacterial capacity were determined. In general, 34 compounds were identified in EO of this material. Moreover, EO has the antioxidant capacity, and the antimicrobial activity was determined by the paper disc diffusion method for antibiotic susceptibility testing. Essential oil does not affect the growth of Staphylococcus aureus - ATCC 25923, Bacillus subtilis - ATCC 11774 and Escherichia coli - ATCC 25922. However, the result also shows that EO of A. conyzoides leaves can inhibit the growth of Salmonella enteritidis - ATCC 13076

Microwave-Assisted Extraction of Pectin from Passion Fruit Peels under Alkaline Conditions

In this study, microwave-assisted extraction (MAE) of pectin from passion fruit (Passiflora edulis Sims) peels has been investigated together with the alkaline extraction conditions such as NaOH concentration (60-220 mM), solid-to-liquid (SL) ratio (1:20-1:40, g/mL), extraction time (3-11 min), and microwave power (167-502 W) on the yield of crude pectin, purity, and degree of esterification (DE) of pectin. The results indicated that all these factors significantly affected the extraction efficiency and purity of recovered pectin. The best extraction condition was found to be as follows: NaOH concentration of 180 mM, SL ratio of 1:35 g/mL, extraction time of 7 min, and microwave power of 376 W. Under these conditions, the experimental crude pectin yield, purity, and DE value were 14.2%, 87.4%, and 92.6%, respectively. The pectin obtained was considered as high-methoxyl pectin (HMP) and the microstructure of initial peels powder completely changed under microwave heating

Essential oil of Citrus hystrix DC.: A mini-review on chemical composition, extraction method, bioactivities, and potential applications in food and pharmaceuticals

Citrus hystrix DC. is a common herb in tropical regions. Its essential oils are now widely researched and applied because of their high economic value and safety for humans and are interesting materials for future trends. This review provides an extensive overview of the biological activities of C. hystrix essential oil, characterized predominantly by citronellal, ?-Pinene, sabinene, limonene, and terpinene-4-ol, which are deciding factors in antimicrobial, antioxidant, insect repellent, anti-tumor, and anti-inflammatory properties. Therefore, it is applied in the fields of food preservation and pharmaceuticals. However, these applications should consider the ratio of these components in the essential oil, which is variable when using materials from different parts of the plant and depending on the original location of the plant, growth stages, traditional or modern extraction methods, and pre-treatment methods

Optimization of ultrasound-assisted extraction of phenolic compounds from fresh Moringa oleifera leaves with a response surface methodology and comparison with the Soxhlet extraction method

ABSTRACT. The present study evaluated the optimum conditions of ultrasound-assisted extraction (UAE) and Soxhlet extraction (SE) of antioxidant capacities and total phenolics from fresh Moringa oleifera leaves, using the response surface methodology. Spectrophotometric method with Folin–Ciocalteu and 2,2-diphenyl-1-picrylhydrazyl (DPPH) reagents was used to determine the total phenolic content (TPC) and the antioxidant activity (AA), respectively. The four models obtained showed the non-linear and quadratic dependences of both measured responses (TPC and AA) which were influenced significantly by all control variables including the acetone solvent (70%, v/v) to solid (SS) ratio, extraction time, and extraction temperature of both extraction methods. Furthermore, at the same extraction temperature, the extraction efficacy of UAE was better than SE as significantly shorter extraction time, less extraction solvent, but higher bio-active content was experienced. The optimal UAE conditions included a SS ratio of 31:1 (mL/g), extraction time of 26 min, and extraction temperature of 59 oC, resulting in the maximum TPC (34.36 mg GAE/g dry weight, DW) and AA (491.9 µmol TE/g DW) in the extracts. In addition, the models proposed were considered to be accurate and reliable for predicting the TPC and AA of fresh M. oleifera leaf extract. The research findings also imply potential applications for ultra-sonication extraction to produce the extracts from fresh M. oleifera leaves for pharmaceutical industry as well as food technology.   KEY WORDS: Antioxidant activity, Herbal plant, Model, Polyphenols, RSM   Bull. Chem. Soc. Ethiop. 2022, 36(2), 261-275.                                                                DOI: https://dx.doi.org/10.4314/bcse.v36i2.

Extraction of Polyphenols from Mentha aquatica Linn. var. crispa

Mentha aquatica Linn. var. crispa is commonly used as a spice in many Asian countries. Although its biological activities, such as its applications, antimicrobial properties, have been studied, its antioxidation properties have not been investigated. This study establishes the most suitable extraction conditions concerning the independent variables affecting the total polyphenol content (TPC) and antioxidant activity (AA) of M. aquatica extract (stem and leaf). Investigated factors include the type of solvent used; solvent concentration, the ratio of raw material to solvent, extraction time and extraction temperature. The efficiency of polyphenol extraction was evaluated by TPC and AA through the ability to neutralize the free radicals 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2\u27-azinobis (3-ethylbenzothiazoline-6- sulfonic acid) (ABTS), and the ferric reducing antioxidant power (FRAP) was used as the evaluation indicator. The results have shown that acetone at a concentration of 50%, at a ratio of 1:20 (w/v), extraction time of 2 h and a temperature of 40 °C give the highest values of TPC and AA, with values of 120.92 mg GAE g-1 dw for TPC, 169.36 μmol TE g-1 dw by DPPH assay, 264.03 μmol by ABTS assay, and 425.35 μmol Fe2+ g-1 dw by FRAP assay. This study demonstrates that extracts of M. aquatica can be used for research as food antioxidant

Extraction of Polyphenols from Mentha aquatica Linn. var. crispa

Mentha aquatica Linn. var. crispa is commonly used as a spice in many Asian countries. Although its biological activities, such as its applications, antimicrobial properties, have been studied, its antioxidation properties have not been investigated. This study establishes the most suitable extraction conditions concerning the independent variables affecting the total polyphenol content (TPC) and antioxidant activity (AA) of M. aquatica extract (stem and leaf). Investigated factors include the type of solvent used; solvent concentration, the ratio of raw material to solvent, extraction time and extraction temperature. The efficiency of polyphenol extraction was evaluated by TPC and AA through the ability to neutralize the free radicals 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2\u27-azinobis (3-ethylbenzothiazoline-6- sulfonic acid) (ABTS), and the ferric reducing antioxidant power (FRAP) was used as the evaluation indicator. The results have shown that acetone at a concentration of 50%, at a ratio of 1:20 (w/v), extraction time of 2 h and a temperature of 40 °C give the highest values of TPC and AA, with values of 120.92 mg GAE g-1 dw for TPC, 169.36 μmol TE g-1 dw by DPPH assay, 264.03 μmol by ABTS assay, and 425.35 μmol Fe2+ g-1 dw by FRAP assay. This study demonstrates that extracts of M. aquatica can be used for research as food antioxidant