Aqueous Acetone Research Articles

PHYTOCHEMICAL STUDY TO VALIDATE THE ETHNOBOTANICAL IMPORTANCE OF Dioscorea steriscus TUBERS OBTAINED FROM ZIMBABWE

Modern people have embraced plants as a source of useful bioactive compounds. As such, plants with medicinal properties have become essential components in human life. The purpose of this study was to investigate the phytochemical profile of the extract of Dioscorea steriscus tubers obtained from Zimbabwe. Phytochemicals were extracted from tubers of D. steriscus using aqueous acetone. UV-Visible Spectrophotometry, Fourier transform infrared (FTIR) spectrometry and highperformance liquid chromatography (HPLC) techniques were used to determine the phytochemical profile of the tuber extract. The yield of phytochemicals extracted from D. steriscus tubers was found to be 6.38 %. The presence of bioactive compounds possessing phenyl, organic hydroxyl, amine, carboxyl, carbonyl, acyl, alkyl and aromatic functional groups was confirmed using UVVisible and FTIR analysis. The presence of substantial amounts of vanillic acid and kaempferol in D. steriscus tubers was confirmed using HPLC analysis. In support of the ethnobotanical values of Dioscorea species, the study confirmed the presence of potent phytochemicals in the extract of D. steriscus tubers obtained from Zimbabwe.

Carbon nanodots for ultrasensitive fluorescent detection of aqueous acetone based on synergistic electron and energy transfer

Sensing of acetone in aqueous solution is important for both environmental and medical applications. However, current probes suffer from low sensitivity and a slow response. In this work, carbon nanodots (CNDs) derived from β-Lactoglobulin were developed for highly sensitive detection of aqueous acetone. The CNDs possessed both spectral matching and surface recognition sites toward acetone. Selective fluorescent quenching of the CNDs by acetone was realized via inner filter effect. Moreover, photoinduced electron transfer from the CNDs to acetone further contributed to the suppressing of the fluorescent signal. The synergistic effect of electron and energy transfer resulted in high sensitivity of the CNDs probe, the limit of detection reached as low as 0.5 μM. The unique ultraviolet emission and tunable surface amino groups of the CNDs were responsible for their superior sensing performance.

The structure of mixtures of water and acetone derived from their cohesive energy densities and internal pressures

The cohesive energy densities ced and the internal pressures Pint of aqueous acetone mixtures are calculated from literature data for the entire composition range at 298.15 K at saturation pressures. The ratios Pint/ced are measures of the ‘structuredness’ of the studied fluids, the small values noted signify ‘tight’ structures, due to the hydrogen bonding. The ‘tighter’ the structure, the larger is the surface tension of the mixtures. This structural feature diminishes in intensity as the temperature and the acetone contents are increased.

Nanofiber Based Organic Solvent Anion Exchange Membranes for Selective Separation of Monovalent anions.

Present anion exchange membranes are generally constructed by simple and positively charged polymers with insufficient organic solvent resistance, and exhibit a low selectivity in the separation of anions. Here, dissolving poly(paraphenylene terephthalamide) nanofibers into small nanofibers and performing a reaction with quaternary ammonium groups in the one-dimensional small nanofibers, high-performance anion exchange membranes were successfully fabricated. By increasing the 2,3-epoxypropyl trimethylammonium chloride content, the synthesized amide nanofiber quaternary ammonium membranes (ANF#QA) exhibited a higher anion exchange capacity (as high as 1.75 mmol·g-1) and achieved a high electrochemical performance. In electrodialysis, the ANF#QA-10 membrane showed an exceptional Cl- selectivity in dilute and concentrated cells. Due to the dense structure and presence of carboxyl groups on the nanofibers, the ANF#QA membranes exhibited a selective separation of monovalent anions. After 48 h of immersion in aqueous acetone solutions, the final ANF#QA-10 membrane exhibited high desalination and concentration efficiency as the initial membrane. This work highlights the promising use of positive charges on small nanofibers, and proposes the design of a special anion exchange membrane, which can be used for electrodialysis in organic solvent solutions, and to selectively separate monovalent anions.

Bioactive Compounds Isolated From In Vitro Callus and Wild Plant of Hibiscus Sabdariffa Linn. And Its Anticancer Activities

Bioactive compounds were isolated from in vitro callus as well as wild plant of Hibiscus sabdariffa Linn. is an annual shrub belonging to the family Malvaceae. The bioactive compounds were isolated from two different organic extracts are methanolic crude and acidified aqueous acetone. These extracts were analyzed antioxidant potential by free radical scavenging activity of DPPH and Total antioxidant activities. The strong DPPH free radical scavenging activity of the acidified aqueous acetone and methanolic extracts of wild plant and in vitro callus of H. sabdariffa showed maximum of 94.03 and 94.50% of inhibition, respectively. IC50 value of acidified aqueous acetone and methanolic extracts of wild plant and in vitro callus was 35.77 and 30.47 µg/mL concentrations, respectively. Based on the antioxidant potential, the isolated compounds were studied the antiviral, anticancer activities. The antiviral activity of H. sabdariffa show evidence of antiviral activity for H1N1 and FLU B viruses by using Vero cell line. The good antiviral activity was observed both extracts as well as isolated compounds. In vitro cytotoxicity study was carried out for the extract and isolated compounds of extracts of plant and callus by used human cervical carcinoma cells (HeLa) and human colon carcinoma cells (HT 29). Apoptosis cell death percentage was observed in and human carcinoma cancer cells (HT 29) with H. sabdariffa and its isolated compounds by DNA fragmentation method. We could observe distinct ladder pattern in the compounds treated cells. The DNA fragmentation induced by the compounds indicating programmed cell death. The present work strongly justifies that the isolated compounds of Hibiscus sabdariffa is a good candidate for anticancer.

Predictive Models for Optimisation of Acetone Mediated Extraction of Polyphenolic Compounds from By-Product of Cider Production

Response surface methodology (RSM) was applied to provide predictive models for optimisation of extraction of selected polyphenolic compounds from cider apple pomace under aqueous acetone. The design of experiment (DoE) was conducted to evaluate the influence of acetone concentration % (v/v), solid-to solvent ratio % (w/v), temperature (&#730C) and extraction time (min) and their interaction on phenolic contents, using the Central Composite Rotatable Design (CCRD). The experimental data were analysed to fit statistical models for recovery of phenolic compounds. The selected models were significant (P 0.05), except for Chlorogenic acid and Quercetin 3-glucoside which had significant lack of fits (P R2 > 0.9000 and adjusted reasonable agrees with predicted . Coefficient of variation < 5% for each determination at the 95% confidence interval. These models could be relied upon to achieve optimal concentrations of polyphenolic compounds for applications in nutraceutical, pharmaceutical and cosmetic industries.

Di-functional luminescent sensors based on Y3+ doped Eu3+ and Tb3+ coordination polymers: fast response and visible detection of Cr3+, Fe3+ ions in aqueous solutions and acetone.

With the careful modulation of the relative ratio of Y3+/Eu3+and Y3+/Tb3+, two series of bimetallic RE-CPs (EuxY1−x and TbxY1−x) were successfully obtained through the isomorphous substitution method. Interestingly, the introduction of Y3+ ions does not change the fluorescence characteristic peak of 1-Eu and 1-Tb, but enhances its fluorescence lifetime and quantum yield. Experimental and theoretical simulation results show the co-doping process changes the intramolecular energy transfer process and reduces the non-radiative transition resulting from concentration quenching. Eu0.1Y0.9 and Tb0.1Y0.9 with the largest luminescence lifetime were selected as the representative research objects, their potential application for the detection of toxic metal ions and organic molecules was further investigated. Interestingly, Eu0.1Y0.9 and Tb0.1Y0.9 demonstrate high sensitivity and good selectivity towards Fe3+, Cr3+ and acetone. Besides, fine fluorescence visibility provides the necessary conditions for the preparation of simple and fast response fluorescent test papers in order to achieve real-time and convenient detection of these toxic materials.

&amp;lt;i&amp;gt;In Vivo&amp;lt;/i&amp;gt; Antioxidant and Anti-inflammatory Effects of &amp;lt;i&amp;gt;Balanites aegyptiaca&amp;lt;/i&amp;gt; (L) Del (Balanitaceae) Galls and Leaves

Balanites aegyptiaca (L.) Del. (Balanitaceae), a tropical plant is well known for its widespread uses in Burkina Faso traditional medicine. The present study aims to evaluate the anti-inflammatory effect of B. aegyptiaca trough the turpentine-induced inflammation. The aqueous acetone extracts of galls and leaves have been used to test the anti-inflammatory effects on adult male Wistar-Bratislava albino rats. Total leukocytes count was performed with an optical microscope (Olympus), using a Burcker-Turk counting-chamber. The nitric oxides synthesis (NOx), the total oxidative status (TOS) and total antioxidant response (TAR) of the serum were measured using a colorimetric assay. The results have showed that all the extracts reduced significantly (p<0.0001) the total leukocytes and total nitrites and nitrates levels in the rats serum. The oxidative stress evaluation showed that the treatment with any dose of B. aegyptiaca gall and leaf extracts was significantly decreased (p<0.0001) the total oxidative status. Moreover, these extracts have been prevented the Turpentine oil induced inflammation by increasing the total antioxidant response. TAR increasing did correlated to TOS decrease by comparison with the inflammation group. In general, an interesting anti-inflammatory effect was found in this study with the greatest activity found in the gall extracts. B. aegyptiaca could then be a potential source of natural antioxidants and anti-inflammatories.

Application of pressurized liquid extraction on isolation of fennel seeds' polyphenols fractions

AbstractDue to nowadays endeavoured green approach, the utilization of environmentally-friendly extraction techniques is encouraged, where pressurized liquid extraction (PLE) provides such possibility. The PLE application allows shorter extraction time and simultaneously less solvent consumption through combined temperature and pressure effect, thus improving energetic and economic efficiency. Accordingly, in order to accomplish satisfactory extraction yield, it is necessary to optimize PLE conditions, depending on sample type and aimed compounds. As fennel (Foeniculum vulgare Mill.) seeds are rich source of structurally different bioactive compounds, this study aimed to examine the influence of PLE temperature (75 and 100 °C), static time (5 and 10 min) and cycle number (1, 2 and 3) on the content of fennel seeds’ polyphenols fractions: total hydroxycinnamic acids (THA), total flavonols (TF) and total flavan-3-ols (TFO). For this purpose, samples of grinded dry fennel seeds were extracted according to the mentioned PLE conditions in serial exhaustive extraction using solvents ordered by its polarity: hexane, aqueous acetone solution (30 %, v/v) and aqueous methanol solution (30 %, v/v). After defatting with hexane, acetone (AE) and methanol (ME) extracts of residues were collected (n = 24) and used for spectrofotometrically determination of THA, TF and TFO. In order to access data about effect of examined PLE conditions on analyzed parameters, results were statistically analyzed using multivariate analysis of variance (MANOVA) and Tukey's HSD test at significance level p ≤ 0.05. Obtained results showed that observed fractions of polyphenols were present in 4–5 folds higher amounts in AE compared to ME, where established grand means in AE were as follows: THA = 312.82 mg/100 g, TF = 113.23 mg/100 g and TFO = 29.01 mg/100 g, while in ME they were THA = 56.90 mg/100 g, TF = 28.78 mg/100 g and TFO were determined in traces. As for influence of extraction temperature and time, content of all tested compounds was significantly affected by examined sources of variation in extracts of both solvent types, except static time on ME’ THA content. Generally, 100 °C/10 min/3 cycles were conditions which yielded the highest THA, TF and TFO in AE, while ME results showed diversity upon examined conditions. Accordingly, the highest THA content was established at lower temperature (75 °C/10 min/2 cycles), while 100 °C/10 min/3 cycles conditions documented the greatest TF content.

Isolation and Characterization of Oligomeric Procyanidins Rich PolyphenolFraction of Cinnamomum Zeylanicum Bark and it’s In Vitro Antidiabetic Studies

Background Cinnamomum zeylanicum Blume bark a spice commonly used in the Indian household has been shown to have insulin-like biological activity.Objective The present work was aimed at isolation and characterization of oligomeric procyanidins OPCs rich polyphenol fraction from C. zeylanicum bark and to carry out its in vitro anti-diabetic activity.Material and Methods The polyphenol fraction from C. zeylanicum bark was afforded by extracting the bark with a series of solvents such as 30 aqueous acetone followed by hexane and butanol. The fraction was subjected to liquid chromatographyndashmass spectrometry LCMS analysis for characterization. From the LCMS data presence of a few OPCs was confirmed. In vitro anti-diabetic activity was performed on the fraction of the bark by alpha-amylase inhibition and non-enzymatic hemoglobin glycosylation assays.Results and Conclusion The fraction showed potential inhibition of glycosylation at half minimal inhibitory concentration IC50 value of 102 microgmL while an alpha-amylase inhibition was observed to be poor at an IC50 value of 540 microgmL. Thus the fraction showed potential anti-diabetic effect by antioxidant mechanism.Keywords C. zeylanicum Polyphenols Oligomeric procyanidins alpha-amylase inhibition Hemoglycosylation

Are fermentation products promising feedstock for high-density bio-fuel? domino reactions for upgrading aqueous acetone–butanol–ethanol mixtures

Upgrading aqueous acetone–butanol–ethanol mixtures to high-density bio-fuels is realized via the three-step domino reaction in a green way.

Bioactive compounds and antioxidant capacity in fennel seeds influenced by pressurized liquid extraction

AbstractFennel (Foeniculum vulgare Mill.) is a well-known aromatic plant, widely used as spice and remedy herb. It provides many beneficial effects and is used as diuretic and expectorant, as well as for various dyspeptic disorders. Beside essential oils, fennel seeds are abundant with various phenols, which are known as strong antioxidants and thereby contribute to human health. Among different extraction methods for phenols isolation, pressurized liquid extraction (PLE) represents a novel technique with numerous advantages over conventional extraction approaches. Its efficiency manifests through combination of high temperature and pressure, enabling extraction time shortening, as well as decreased solvent consumption, thus being environment-friendly technique. In order to achieve maximum extraction yield, it is of great importance to select optimal PLE conditions, e.g., extraction temperature and time. Additionally, solvent selection also affects on content of targeted compounds, where phenols amount depends on polarity of solvent. Hence, the aim of this study was to examine the effect of temperature (75 and 100 °C), static time (5 and 10 min) and cycle number (1, 2 and 3) on total phenols (TP) and total flavonoids (TF) content, as well as the antioxidant capacity (AC) in fennel seeds using three-step exhaustive PLE. Firstly, grinded dry fennel seeds were subjected to PLE using non-polar solvent (hexane) under the mentioned conditions in order to remove seeds' lipid fraction. Afterwards, defatted samples were extracted with polar solvents by the increasing polarity: aqueous acetone solution (30 %, v/v) followed by aqueous methanol solution (30 %, v/v). Obtained acetone (AE) and methanol (ME) extracts (n = 24) were analyzed for TP (Folin-Ciocalteu method), TF (aluminium chloride colorimetric assay) and AC [ferric reducing antioxidant power (FRAP) method]. Multivariate analysis of variance (MANOVA) and Tukey's HSD test (p ≤ 0.05) were applied for statistical analysis of collected data. Expectedly, AE were described with higher values of analyzed parameters (grand means: TP = 416.18 mg/100 g, TF = 41.87 mg/100 g, AC = 359.57 mg AAE/100 g) in comparison with ME (grand means: TP = 80.25 mg/100 g, TF = 16.41 mg/100 g, AC = 96.13 mg AAE/100 g. Furthermore, all examined influences significantly affected TP, TF and AC in all samples, except temperature on TP in ME. Thus, conditions of 100 °C/10 min/3 cycles showed the greatest yield of tested parameters in AE, while 100 °C/5 min/1 cycle were sufficient for maximum TP and AC levels in ME. Regarding TF in ME, slightly longer extraction time was required to achieve the highest efficiency (100 °C/10 min/1 cycle).

Enhanced adsorption of aqueous acetone by modified powdered activated carbon

ABSTRACT Acetone, a small molecule organic compound, is freely soluble and volatile. To improve the removal rate of acetone, three different types of powdered activated carbon (PAC) were compared and then modified with formic acid and NaOH to optimize the adsorption capacities of PAC. The adsorption mechanism and the effect of physical–chemical properties of PAC to the adsorption were clarified. Results show that PAC produced from wood performed best adsorption capacities. The pseudo-second-order model and the Freundlich model accurately described the adsorption behaviour, while lower temperature was more conducive to the adsorption process. PAC giving a higher acetone adsorption capacity had a larger specific surface area, a richer micropore structure, a larger micropore volume, a smoother surface, with more acidic, oxidizing functional groups. The adsorption removal efficiency of modified PACs with formic acid was improved from 60.89% to 82.93%, while NaOH modification decreased the adsorption capacity. The positive effect of formic acid was attributed to the formation of novel acidic oxygen-containing functional groups, which was supported from the NaOH treatment that removed original acidic oxygen-containing functional groups, contrarily the formation of novel alkaline reducing functional groups did not restore the acetone adsorption capacity. We conclude that wooden PAC is a suitable adsorbent for acetone, in particular after pretreatment with formic acid.

Antioxidant Potential and the Characterization of Arachis hypogaea Roots.

Arachis hypogaea roots are used as traditional Chinese medicine to treat different ailments, and the present study involves the exploration and comparison of phenolic profile and antioxidant activities (ABTS+ and DPPH assay) of A. hypogaea root extract in different solvents. 70% aqueous acetone and 70% aqueous ethanol were proved to be the best solvents to recover total phenolic compounds, with a yield of 42.59 ± 1.96 and 41.34 ± 0.92 mg/g dry weight of extract, respectively. ABTS+ radical scavenging activity was the highest in 70% aqueous ethanol, while the absolute methanol extract showed the highest DPPH radical scavenging activity (29.50 ± 2.19 μg/mL). Furthermore, phytochemical profiling of 70% acetone extract of A. hypogaea roots was performed by LC-ESI-TOF-MS analysis which in turn indicated the presence of diverse compounds in the A. hypogaea root extract, namely, quinones, stilbenoids, and flavones and flavonoid glucosides.

Influence of physical and chemical barrel sanitization treatments on the volatile composition of toasted oak wood

Various chemical and physical barrel sanitization methods were evaluated in terms of their effect on oak volatiles in situ. A gas chromatography–mass spectrometry (GC–MS) method using a programmable temperature vaporizing (PTV) injector in solvent-split mode was developed and validated for the analysis of oak volatiles extracted in aqueous acetone. Results revealed that barrel sanitization methods affected oak volatile compounds and that the degree of modification depended on the type of sanitization method and the duration or concentration of the applied treatment. Sanitization predominantly lowered concentrations of oak volatiles when hot water treatment at 80 °C, steam, ethanol treatment, and a 200 ppm peracetic acid treatment were applied. Gaseous sulphur dioxide, aqueous ozone, and hot water treatment at 60 °C, however, had no significant effect. This work provides the first direct comparison of an array of barrel sanitization methods in relation to their impact on desirable oak volatile compounds.

DENDROBENTHAMIDIA CAPITATA (WALL.) HUTCH. FRUIT (BHOMORA): AN OPULENT SOURCE OF POLYPHENOLS WITH ANTIOXIDANT, ANTI-ELASTASE, ANTI-COLLAGENASE, AND ANTI-TYROSINASE ACTIVITIES FROM INDIAN HIMALAYAN REGION

Dendrobenthamidia capitata (Wall.) Hutch. fruit (Bhamora) is a popular yet underexplored wild edible fruit of Uttarakhand state of Indian Himalayan region. Therefore, the present study was aimed to analyze D. capitata fruit for its phenolic contents, antioxidant, anti-elastase, anti-collagenase, and anti-tyrosinase activities using in- vitro assays. Phenolics and flavonoids were extracted using 80 % aqueous acetone and acid acetone as solvents. Our analysis revealed high values of total phenolic contents of 4.38±0.08 mg gallic acid equivalents (GAE). g-1 fruit weight and total flavonoid contents of 7.47±0.66 mg catechin equivalents (CE). g-1 fruit weight in the acid acetone fruit extracts of D. capitata. D. capitata fruit extracts demonstrated remarkable antioxidant activities (ABTS+, 1,1- diphenyl-2-picrylhydrazyl, superoxide anion, linoleate peroxyl radicals scavenging, and ferric reducing activities) and notable anti-elastase, anti-collagenase, and anti-tyrosinase activities. High resolution liquid chromatography– mass spectroscopy analysis revealed presence of six phenolic compounds, namely, dihydrorobinetin, dhydromyricetin, retusin dimethyl ether, rotenone, bergenin (C-glycoside of 4-O-methyl gallic acid) and peucenin in fruit extracts. This study recommends utilization of D.capitata fruit as functional food with prospective pharmaceutical, nutraceutical, and cosmeceutical properties.

DENDROBENTHAMIDIA CAPITATA (WALL.) HUTCH. FRUIT (BHOMORA): AN OPULENT SOURCE OF POLYPHENOLS WITH ANTIOXIDANT, ANTI-ELASTASE, ANTI-COLLAGENASE, AND ANTI-TYROSINASE ACTIVITIES FROM INDIAN HIMALAYAN REGION

Dendrobenthamidia capitata (Wall.) Hutch. fruit (Bhamora) is a popular yet underexplored wild edible fruit of Uttarakhand state of Indian Himalayan region. Therefore, the present study was aimed to analyze D. capitata fruit for its phenolic contents, antioxidant, anti-elastase, anti-collagenase, and anti-tyrosinase activities using in- vitro assays. Phenolics and flavonoids were extracted using 80 % aqueous acetone and acid acetone as solvents. Our analysis revealed high values of total phenolic contents of 4.38±0.08 mg gallic acid equivalents (GAE). g-1 fruit weight and total flavonoid contents of 7.47±0.66 mg catechin equivalents (CE). g-1 fruit weight in the acid acetone fruit extracts of D. capitata. D. capitata fruit extracts demonstrated remarkable antioxidant activities (ABTS+, 1,1- diphenyl-2-picrylhydrazyl, superoxide anion, linoleate peroxyl radicals scavenging, and ferric reducing activities) and notable anti-elastase, anti-collagenase, and anti-tyrosinase activities. High resolution liquid chromatography– mass spectroscopy analysis revealed presence of six phenolic compounds, namely, dihydrorobinetin, dhydromyricetin, retusin dimethyl ether, rotenone, bergenin (C-glycoside of 4-O-methyl gallic acid) and peucenin in fruit extracts. This study recommends utilization of D.capitata fruit as functional food with prospective pharmaceutical, nutraceutical, and cosmeceutical properties.

Analysis of Phenolic Composition of Byproducts (Seeds and Peels) of Avocado (Persea americana Mill.) Cultivated in Colombia.

The byproducts (seeds and peels) of an avocado cultivated in the south of Colombia were extracted with aqueous acetone and their antioxidant properties were measured with ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and DPPH (2,2-diphenyl-1-picrylhydrazyl) assays, and total polyphenol content was determined by Folin–Ciocalteu method. A bioguided fractionation was performed, first by SPE (solid phase extraction) on Amberlite XAD-7, and then by size exclusion chromatography on Sephadex LH-20. The polyphenolic-rich extracts and their fractions were analyzed by ultra-performance liquid chromatography–electrospray ionization–mass spectrometry (UPLC-ESI-MS/MS), finding the presence of organic acids, hydroxycinnamic acids, catechins, free and glycosylated flavonoids, and dimeric and trimeric procyanidins. Catechin, epicatechin, six quercetin derivatives, four dimeric procyanidins (three type B and one type A), and three trimeric procyanidins (two type B and one type A) were detected in the most active fractions of avocado peel and seeds. The most antioxidant fractions contain the higher molecular weight phenolic compounds (condensed tannins).

Components of the extracts of the knot wood of Dalbergia Sissoo Linn. and their antioxidant activity

The composition of the extract from the Dalbergia Sissoo Linn. knot wood was studied. Components obtained by extraction with 95% aqueous acetone were isolated, purified by HPLC, and identified by NMR spectroscopy and mass spectrometry as 7,6,3’,5’-trihydroxyflavanone (1), 7,3’,4’-trihydroxy-6-methoxyflavanone (2), 7,3’,5’-trihydroxyflavanone (3), 6-hydroxy-7-methoxy-4-phenyl-2H-chromen-2-one (dalbergin) (4), 2-methoxy-5-(1-phenylallyl)cyclohexa-2,5-diene-1,4-dione (dalbegione) (5), and 2,4-dimethoxy-5-(1-phenylallyl)phenol (dalbergiphenol) (6). In the extract from the Dalbergia Sissoo Linn. wood knots, compounds 1–3 were found for the first time. The isolated compounds demonstrated notable antioxidant ability determined by using the amperometric method.

Aquatic weeds as novel protein sources: Alkaline extraction of tannin-rich Azolla

The aquatic weed Azolla is a potential protein crop due to its prolific growth and high protein content, supported entirely by nitrogen-fixing symbionts. Alkaline protein extraction at pH 8 followed by acid precipitation allowed recovery of 16–26% of the biomass nitrogen, while at pH 10.5 nitrogen recovery improved to 35–54%. This pH effect was typical of ferns of the family Salviniaceae, and may be explained by high concentrations of condensed tannins (CTs) in the biomass that precipitate protein at mild pH. Two approaches were tested to increase protein yield and reduce protein binding by CTs. Pre-extraction with aqueous acetone (70 v/v%) removed 76–85% of the CTs and subsequent alkaline extraction at pH 12.5 and 95 °C recovered 38% of the biomass nitrogen. Extraction with 1.5% of PEG as a CT-binding agent, also permitted to recover 38% of the nitrogen, under milder conditions of pH 8 and 45 °C.