Experimental Design and Optimization of Recovering Bioactive Compounds from Chlorella vulgaris through Conventional Extraction

Microalgae contain an abundance of valuable bioactive compounds such as chlorophylls, carotenoids, and phenolics and, consequently, present great commercial interest. The aim of this work is the study and optimization of recovering the aforementioned components from the microalgae species Chlorella vulgaris through conventional extraction in a laboratory-scale apparatus using a “green” mixture of ethanol/water 90/10 v/v. The effect of three operational conditions—namely, temperature (30–60 °C), duration (6–24 h) and solvent-to-biomass ratio (20–90 mLsolv/gbiom), was examined regarding the extracts’ yield (gravimetrically), antioxidant activity, phenolic, chlorophyll, and carotenoid contents (spectrophotometric assays), as well as concentration in key carotenoids, i.e., astaxanthin, lutein, and β-carotene (reversed-phase–high-performance liquid chromatography (RP–HPLC)). For this purpose, a face-centered central composite design (FC-CCD) was employed. Data analysis resulted in the optimal extraction conditions of 30 °C, for 24 h with 37 mLsolv/gbiom and validation of the predicted models led to 15.39% w/w yield, 52.58 mgextr/mgDPPH (IC50) antioxidant activity, total phenolic, chlorophyll, and carotenoid content of 18.23, 53.47 and 9.92 mg/gextr, respectively, and the total sum of key carotenoids equal to 4.12 mg/gextr. The experimental data and predicted results were considered comparable, and consequently, the corresponding regression models were sufficiently reliable for prediction.

Extraction of Kaempferitrin and Astragalin from Justicia Spicigera by Supercritical Fluid Extraction and Its Comparison with Conventional Extraction

A study of supercritical fluid CO2 extraction of kaempferitrin (KM) and astragalin (KG) from Justicia spicigera (muicle) was conducted. A 33 Box-Behnken design was used to analyze the effects of pressure (200-300 bar), temperature (40-60° C), and co-solvent flow rate (0.5-1.0 mL/min). The highest KM and KG concentration were achieved at a pressure of 300 bar, a temperature of 60° C, and co-solvent flow rate of 1.0 mL/min (ethanol 99.5 %), with a constant CO2 flow rate of 5 mL/min and extraction time of 180 min. Under these conditions, the experimental values for KM and KG (115.08±2.81 and 56.63±9.02 mg/100 g of dry powder, respectively) were similar to those calculated by the models (109.0 and 44.07 mg/100 g of dry powder, respectively). The use of 70 % ethanol as co-solvent in the supercritical extraction process considerably improved the yields of KM and KG (562.71±156.85 and 79.90±18.03 mg/100 g of dry powder, respectively) compared to the 99.5 % ethanol extractions. The conventional extraction showed the highest yields of KM and KG (574.20±65.10 and 113.10±15.06 mg/100 g of dry powder, respectively) at 70° C and extraction time of 120 min. Adequate yields were achieved of KM and KG by supercritical fluid extraction compared with conventional extraction (98 and 70 %, respectively); therefore supercritical fluid extract of J. spicigera could be used in the development of functional foods, as well as its possible use in traditional medicine by the health professionals.

Optimization of Microwave-Assisted Extraction of Polyphenols from Lemon Myrtle: Comparison of Modern and Conventional Extraction Techniques Based on Bioactivity and Total Polyphenols in Dry Extracts

The aromatic herb lemon myrtle is a good source of polyphenols, with high antioxidant and antimicrobial capacity. In this study, the green extraction technique microwave-assisted extraction (MAE) was applied and the extraction parameters were optimized using response surface methodology (RSM) to maximize the extraction yield of phenolic compound and antioxidant properties. Then, it was compared with other popular novel and conventional extraction techniques including ultrasound-assisted extraction (UAE) and shaking water bath (SWB) to identify the most effective technique for extraction of phenolic compounds from lemon myrtle. The results showed that the MAE parameters including radiation time, power, and sample to solvent ratio had a significant influence on the extraction yield of phenolic compounds and antioxidant capacity. The optimal MAE conditions were radiation time of 6 min, microwave power of 630 W, and sample to solvent ratio of 6 g/100 mL. Under optimal conditions, MAE dry extract had similar levels of total phenolic compounds (406.67 ± 8.57 mg GAE/g DW), flavonoids (384.57 ± 2.74 mg CE/g DW), proanthocyanidins (336.54 ± 7.09 mg CE/g DW), antioxidant properties, and antibacterial properties against (Staphylococcus lugdunensis and Bacillus cereus) with the other two methods. However, MAE is eight-times quicker and requires six-times less solvent volume as compared to UAE and SWB. Therefore, MAE is recommended for the extraction of polyphenols from lemon myrtle leaf.

Microwave Assisted Extraction of Papaya Leaves and Investigation on Antioxidant Activity

Microwave assisted extraction (MAE) has gained lot of attention due to its advantages such as less solvent consumption, short time period, higher extraction efficiency, therefore serves as better alternative for conventional extraction methods of plant materials. Plant phenolic compounds are important constituents responsible for reducing the oxidative stress that induces tissue damage which is the one of the major causative factors associated with the chronic disease. Papaya plant is a medicinal plant which became popular for the treatment of dengue fever due to its property. Considering the current medicinal importance of the papaya plant, the present study was aimed at microwave assisted extraction of phenolic content from papaya leaf using ethanol, water as solvent and investigate their antioxidant potential. In order to compare the extraction efficiency of phenolic compounds, conventional extraction and microwave assisted extraction method was used to prepare the extracts. Then extracts were subjected to preliminary phytochemical analysis followed by the estimation of total phenolic content by using Folin-Ciocalteu method. Antioxidant activity was investigated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The alcoholic and aqueous extracts of papaya leaf showed the presence of steroids, alkaloids, saponins, carbohydrates, phenolic compounds by preliminary phytochemical analysis. FTIR spectrum of both aqueous and ethanolic extract showed characteristic peak at 3314.62 cm-1, 1635 cm-1 which provide evidence for presence of phenolic compounds. The total phenolic content of the alcoholic and aqueous leaf extracts from MAE was found to be 43.58mg and 80.58 mg/g papaya leaf powder of the Gallic acid equivalent (GAE), respectively. Aqueous solvent was found to be suitable for extraction of phenolic content from papaya leaf and Microwave assisted extracts showed higher phenolic content and therefore potential antioxidant activity. Therefore, papaya leaf is a good candidate to be used as a natural antioxidant for the treatment of various diseases.

Downstream Processing Stages, Comparative Analysis & Extraction Methodologies in Generation of Cannabinoids from Cannabis Sativa L. (Hemp)

Due to the intoxicating effects of only a few cannabinoids, the cannabis plant has long been prohibited by legislation in several countries. Recent scientific advancements, along with a growing public awareness of cannabis as a medicinal commodity, prompted law reform, resulting in a historic shift in which demand increased tenfold in less than five years. The technology necessary for cannabis processing and extraction of the most valuable chemical components from the cannabis flower, on the other hand, remains the processing bottleneck. The downstream processing stages and concepts involved in generating cannabinoids from Cannabis Sativa L. (Hemp) biomass are discussed in this study. I evaluated and criticised several pre-treatment procedures and technical alternatives available for large-scale extraction in both categories by dividing extraction technology into seed and trichome. The major focus was on solvent extraction methods, as well as the important decision-making criteria at each stage and the applicable contemporary technology in the sector. I looked at the variables that impact cannabis transformation and how they affect the medicinal functioning of the finished goods. According to current trends, extraction technologies are constantly reviewed and improved, yet they still fall short of market demands. Cannabis sativa has hundreds of bioactive chemicals, making it one of the oldest therapeutic plants utilised by humans. Although the plant's medicinal benefits are undeniable, the biological consequences and interaction of these chemicals are yet unknown. These chemicals' extraction techniques are becoming an important element of current Cannabis-based therapy. Despite this, little is known about how different techniques impact the final composition of Cannabis extracts and, as a result, their medicinal benefits. Different extraction methods, such as maceration, Soxhlet, ultrasound-assisted extraction, and supercritical CO2 extraction methods, were evaluated in this study. The extracts were tested in vitro on human colon cancer and healthy colon cells for cannabis content, antioxidant effects, and in vitro bioactivity. Findings indicate that properly produced cannabis extracts can dramatically reduce cancer cell viability while sparing healthy cells from harmful effects. However, because post-processing of extracts alters not only the actual quantities of the various cannabinoids, but also their relative ratio to the main extracts, it is difficult to anticipate therapeutic response solely on the composition of the crude extract. These effects must be carefully addressed while developing novel medicinal extracts in the future. The natural non-psychoactive and psychoactive cannabinoids in cannabis are increasing its medicinal relevance. To effectively use the natural cannabinoids for therapeutic and forensic reasons, efficient extraction and quantification are required. In comparison to most conventional extraction methods, the supercritical fluid extraction (SFE) process has gained increasing interest due to its selective extraction, short processing time (partly due to the efficient solvent removal process – supercritical fluid to vapour – leaving a solvent free product), low operating cost, and low environmental impact. Microwave-assisted extraction, solid phase microextraction, hard-cap espresso, Soxhlet extraction, high-throughput homogenization, ultrasound-assisted extraction, vacuum distillation of lipid-based extract, and liquid–liquid extraction are discussed as advantages of SFE of cannabinoids over conventional extraction procedures.

Agro-industrial waste as a source of bioactive compounds: ultrasound-assisted extraction from blueberry (Vaccinium myrtillus) and raspberry (Rubus idaeus) pomace

Blueberry and raspberry pomace are a rich source of bioactive compounds that have not been commercially utilized yet, and ultrasound-assisted technology can efficiently extract these compounds. Also, the use of water as a solvent added to the ultrasound-assisted technology improves this eco-friendly process. Therefore, an aqueous eco-friendly extraction, including extraction time and ultrasound presence or absence (conventional extraction) was performed in order to extract bioactive compounds from blueberry and raspberry pomace. Response parameters included levels of anthocyanins, phenolic compounds, and flavonoids, and antioxidant activity determined by DPPH, ABTS, and FRAP methods. Analysis of variance results indicated that ultrasound-assisted extraction for 45 min. was feasible to extract the bioactive compounds. The antioxidant content of the extract obtained by the ultrasound-assisted process was 1.4 times higher on average and the total phenolic concentration was 1.6 times higher (for blueberry 5.02 and for raspberry 2.53 mg gallic acid equivalent/g) compared with those obtained by the conventional process. Thus, the ultrasound-assisted extraction method can be a profitable alternative to extract bioactive compounds from blueberry and raspberry pomace, as it is energy efficient, requires fewer chemicals, and produces less effluent. This eco-friendly technology is therefore viable for food, nutraceutical, and cosmetic industries, and also for reducing food waste.

Pressurized Liquid Extraction Combined with Enzymatic-Assisted Extraction to Obtain Bioactive Non-Extractable Polyphenols from Sweet Cherry (Prunus avium L.) Pomace

Sweet cherry generates large amounts of by-products within which pomace can be a source of bioactive phenolic compounds. Commonly, phenolic compounds have been obtained by conventional extraction methodologies. However, a significant fraction, called non-extractable polyphenols (NEPs), stays held in the conventional extraction residues. Therefore, in the present work, the release of NEPs from cherry pomace using pressurized liquid extraction (PLE) combined with enzyme-assisted extraction (EAE) using PromodTM enzyme is investigated for the first time. In order to study the influence of temperature, time, and pH on the NEPs extraction, a response surface methodology was carried out. PLE-EAE extracts displayed higher TPC (75 ± 8 mg GAE/100 g sample) as well as, PA content, and antioxidant capacity than the extracts obtained by PLE (with a TPC value of 14 ± 1 mg GAE/100 g sample) under the same extraction conditions, and those obtained by conventional methods (TPC of 8.30 ± 0.05 mg GAE/100 g sample). Thus, PLE-EAE treatment was more selective and sustainable to release NEPs from sweet cherry pomace compared with PLE without EAE treatment. Besides, size-exclusion chromatography profiles showed that PLE-EAE allowed obtaining NEPs with higher molecular weight (>8000 Da) than PLE alone.