Kinetic studies for ultrasound-assisted supercritical carbon dioxide extraction of triterpenic acids from healthy tea ingredient Hedyotis diffusa and Hedyotis corymbosa

Phytochemistry, pharmacology, and medical uses of Oldenlandia (family Rubaceae): a review

The Oldenlandia genus comprises approximately 240 species of plants, yet only a limited number of these have been investigated for their chemical composition and medicinal properties. These species contain a wide range of compounds such as iridoids, anthraquinones, triterpenes, phytosterols, flavonoids, anthocyanidins, vitamins, essential oils, phenolic acids, and coumarins. These diverse phytochemical profiles underscore the pharmacological potential of Oldenlandia plants for various medical purposes. Among other chemical constituents, ursolic acid stands out as the most important active compound in Oldenlandia, owing to its proven anticancer, anti-inflammatory, antimicrobial, and hepatoprotective properties. The evaluation of Oldenlandia's pharmacological prospects indicates that the holistic utilization of the entire plant yields the most significant effects. Oldenlandia diffusa showcases anticancer and anti-inflammatory capabilities attributed to its varying constituents. Across a broad spectrum of pharmacological capacities, anticancer research predominates, constituting the majority of medical uses. Oldenlandia diffusa emerges as a standout for its remarkable anticancer effects against diverse malignancies. Antioxidant applications follow, with O. corymbosa demonstrating potent antioxidant properties alongside O. umbellata and O. diffusa. Subsequent priority lies in anti-inflammatory studies, wherein O. diffusa exhibits noteworthy efficacy, trailed by O. corymbosa also takes the lead in antimicrobial activity, with O. umbellata as a strong contender. Additional investigation is essential to ascertain the relative significance of these species in various pharmacological applications. This comprehensive assessment underscores the multifaceted potential of Oldenlandia as a versatile herbal resource, offering diverse pharmacological capacities. The call for sustained exploration and research remains essential to unlock the full extent of Oldenlandia's medicinal benefits.

Recent advancement in ultrasound-assisted novel technologies for the extraction of bioactive compounds from herbal plants: a review

Herbal plants comprise potent bioactives, and they have a potential for the development of functional foods. Ultrasonication technology can be used to enhance the efficiency and quality of these bioactivities. The present review discussed the ultrasound-assisted novel extraction technologies (supercritical carbon dioxide (CO2) and high pressurized liquid), including mechanistic understanding, influencing factors, extract process efficiency, and the recovery of bioactives with an industrial perspective. The strong observations of this study are the novel ultrasound-induced extraction process variables, such as ultrasound amplitude, sonication time, temperature, solid-solvent ratio, and pressure, are significantly influenced and must be optimized for maximum recovery of bioactives. The novel green technologies (ultrasound and assisted) could remarkably improve the extraction efficiency and enhance the quality of green extract. This review will support technological understanding about the impact on process parameters for the extraction of bioactives for the development of functional foods and nutraceuticals.

Comprehensive HPLC fingerprint analysis based on a two-step extraction method for quality evaluation of Perilla frutescens (L.) Britt

Abundant chemical components are key to ensure the evaluation accuracy of fingerprint analysis of traditional Chinese medicines (TCMs). A two-step extraction method combining supercritical fluid extraction (SFE) and water ultrasonic extraction was established for the quality evaluation of Perilla frutescens (L.) Britt. Weakly polar components were extracted under optimal SFE conditions (15% co-solvent (EtOH : n-hexane = 1 : 14, (v/v)), 40 °C, 250 bar, and 30 min), and polar components were subsequently extracted by an ultrasonic step (100% water as solvent, 40 °C, and 45 min). Then, HPLC methods were established, which were validated to be accurate, stable, and reliable. In this work, 25 batches of samples were evaluated and the data were analysed by similarity analysis (SA) and hierarchical cluster analysis (HCA). The similarity values of SFE extracts and aqueous extracts were respectively 0.616-0.999, and 0.252-0.997, proving the importance of the extraction method for the accuracy of the subsequent fingerprint analysis results. For the HCA, 25 samples were divided into two categories (leaves and stems), among which four batches of leaves with less similarity were considered as stems, indicating that quality differences of P. frutescens depending on medicinal parts and origin exist. The two-step extraction method developed in this work has been proved to be suitable for the quality evaluation of TCMs with complex compositions.

Green Extraction of Bioactive Compounds from Plant Biomass and Their Application in Meat as Natural Antioxidant

Plant extracts are rich in various bioactive compounds exerting antioxidants effects, such as phenolics, catechins, flavonoids, quercetin, anthocyanin, tocopherol, rutin, chlorogenic acid, lycopene, caffeic acid, ferulic acid, p-coumaric acid, vitamin C, protocatechuic acid, vitamin E, carotenoids, β-carotene, myricetin, kaempferol, carnosine, zeaxanthin, sesamol, rosmarinic acid, carnosic acid, and carnosol. The extraction processing protocols such as solvent, time, temperature, and plant powder should be optimized to obtain the optimum yield with the maximum concentration of active ingredients. The application of novel green extraction technologies has improved extraction yields with a high concentration of active compounds, heat-labile compounds at a lower environmental cost, in a short duration, and with efficient utilization of the solvent. The application of various combinations of extraction technologies has proved to exert a synergistic effect or to act as an adjunct. There is a need for proper identification, segregation, and purification of the active ingredients in plant extracts for their efficient utilization in the meat industry, as natural antioxidants. The present review has critically analyzed the conventional and green extraction technologies in extracting bioactive compounds from plant biomass and their utilization in meat as natural antioxidants.

Saponin Stabilization via Progressive Freeze Concentration and Sterilization Treatment

Saponin is a biopesticide used to suppress the growth of the golden apple snail population. This study aims to determine the stabilized conditions for saponin storage. The maceration process was used for saponin extraction, and for saponin concentration, progressive freeze concentration (PFC) was used. Afterwards, stability analysis was performed by storing the sample for 21 days in two conditions: Room temperature (26 °C) and cold room (10 °C). The samples kept in a cold room were sterilized samples that undergo thermal treatment by placing the sample in the water bath. The non-sterilized samples were kept in room temperature condition for 21 days. The results showed that saponin stored in the cold room (sterilized sample) has low degradation with higher concentration than those stored at room temperature in stability analysis with the highest saponin concentration (0.730 mg/mL) at a concentration temperature of −6 °C and concentration time of 15 min. The lowest saponin concentration obtained by saponin stored at room temperature (non-sterilized sample) is 0.025 mg/mL at a concentration temperature of −6 °C and concentration time of 10 min. Thus, the finding concluded that saponin is sensitive to temperature. Hence, the best storage condition to store saponin after thermal treatment is to keep it in a cold room at 10 °C.

Extraction of natural products using supercritical fluids and pressurized liquids assisted by ultrasound: Current status and trends

Natural products are a source of a wide range of chemical compounds, from pigments to bioactive compounds, which can be extracted and used in different applications. Due to consumer awareness, the interest in natural compounds significantly increased in the last decades, prompting the search for more efficient and environmentally friendly extraction techniques and methods. Pressurized liquids and fluids (sub and supercritical) are being explored to extract natural compounds within the green process concept. The combination of these techniques with ultrasound has emerged as an alternative to intensify the extraction process efficiently. In this context, this work presents a comprehensive review and current insights into the use of high-pressure systems, specifically supercritical fluid extraction and pressurized liquid extraction assisted by ultrasound, as emerging technologies for extracting bioactive compounds from natural products. The extraction mechanisms, applications, and the influence of operational parameters in the process are addressed, in addition to an analysis of the main challenges to be overcome for widespread application.

A predictive approach to the antioxidant capacity assessment of green and black tea infusions

Contemporary consumers drink significant amounts of tea because of its health–benefits mainly associated to the presence of polyphenols with high antioxidant activity. Therefore, the information how to obtain tea infusion of the highest quality, i.e. with high antioxidant capacity is needed. In this study, the various models for the prediction of total polyphenols and antioxidant activity of green and black tea infusions were developed and compared. Three mathematical equations: Spiro’s, Peleg’s and logarithmic, and two data mining techniques: multivariate adaptive regression splines (MARS) and artificial neural networks (ANNs) were used to build the predictive models. The results obtained show that Spiro’s model could be used for the prediction of green tea quality expressed as total phenolic content or the antioxidant activity (determination coefficients above 0.99), whereas Peleg’s model is more suitable for black tea quality prediction (determination coefficients above 0.99). Data mining techniques (MARS and ANNs) enable to create models fast and of simple application with very good acceptability (determination coefficients above 0.99).

Insights into the Supercritical CO2 Extraction of Perilla Oil and Its Theoretical Solubility

In the current research, the supercritical carbon dioxide (SCCO2) procedure was used to extract volatile oils from perilla leaves. The yields of the volatile oils and the four main constituents, limonene, perillaldehyde, β-caryophyllene, and (Z,E)-α-farnesene obtained by the SCCO2 procedure were 1.31-, 1.12-, 1.04-, 1.05-, and 1.07-fold higher than those obtained by the hydrodistillation technique, respectively. Furthermore, the duration and temperature of extraction were 40 min and 45 °C lower, respectively, in the former procedure compared to the latter technique. These advantages reveal that SCCO2 not only obtains high-quality extracts, but also meets the requirements of green environmental protection. The theoretical solubilities of the volatile oils acquired by the SCCO2 dynamic extraction at various temperatures and pressures were 1.385 × 10−3–8.971 × 10−3 (g oil/g CO2). Moreover, the three density-based models were well correlated with these theoretical solubility data, with a high coefficient of determination and low average absolute relative deviation.

A green approach for the extraction and characterization of oridonin and ursolic and oleanolic acids from Rabdosia rubescens and its kinetic behavior

An ultrasound-assisted supercritical carbon dioxide (USC-CO2) procedure was developed for the extraction of ursolic acid, oleanolic acid and oridonin from Rabdosia rubescens, with yields that were 9.84-10.46 and 15.43-21.10% higher than those of the conventional SC-CO2 and heat-reflux extractions, respectively. USC-CO2 uses a shorter extraction time (1.83-2.09 times) and less organic solvent (3.39-173.25 times) to operate at a lower extraction temperature (5-16 °C). The dominant component in the extract was oridonin, which may indicate that the kinetic behavior in the extraction system is predominated by that of oridonin. Furthermore, the USC-CO2 and conventional SC-CO2 dynamic extraction kinetics of oridonin from R. rubescens were well described by the second-order rate and Fick's second law models. The extraction rate constant, energy of activation for diffusion, Biot number and thermodynamic parameters were deduced from the data obtained. These results provide valuable insights into the USC-CO2 and conventional SC-CO2 procedures.

Effect of emergent non-thermal extraction technologies on bioactive individual compounds profile from different plant materials

Extraction is the first step for isolation and purification of interesting bioactive compounds, by mixing of the plant material with an adequate solvent. Those bioactive compounds are, usually, secondary metabolites, such as phenolic acids and flavonoids which are present in closed insoluble structures, making its extraction a challenge. There are many different traditional extraction methods, such as Soxhlet, heat reflux, and maceration. Nevertheless, due to several disadvantages, they are being replaced by new methods, using emergent technologies, such as high hydrostatic pressure, ultrasounds, pulsed electric fields, and supercritical fluids. The use of novel technologies allows enhancing mass transfer rates, increasing cell permeability as well as increasing secondary metabolite diffusion, leading to higher extraction yields, fewer impurities on the final extract, extractions at room temperature with thermo-sensitive structures preservation, use of different non-organic solvents, low energy consumption, short operation time, and have no significant or lower effect on the structure of bioactive compounds. This paper aims to review the effect of the main emergent extraction technologies (high hydrostatic pressure, pulsed electric fields, ultrasounds, and supercritical fluid assisted) on the individual profile of bioactive compounds from plant material.

Production of oridonin-rich extracts from Rabdosia rubescens using hyphenated ultrasound-assisted supercritical carbon dioxide extraction

BACKGROUND

Among active components in Rabdosia rubescens, oridonin has been considered a key component and the most valuable compound because it has a wide range of activities beneficial to human health. To produce a high-quality oridonin extract, an alternative hyphenated procedure involving an ultrasound-assisted and supercritical carbon dioxide (HSC-CO₂ ) extraction method to extract oridonin from R. rubescens was developed in this study. Fictitious solubilities of oridonin in supercritical CO₂ (SC-CO₂ ) with ultrasound assistance were measured by using the dynamic method at temperatures ranging from 305.15 K to 342.15 K over a pressure range of 11.5 to 33.5 MPa.

RESULTS

Fictitious solubilities of oridonin at different temperatures and pressures were over the range of 2.13 × 10^-6 to 10.09 × 10^-6 (mole fraction) and correlated well with the density-based models, including the Bartle model, the Chrastil model, the Kumar and Johnston model and the Mendez-Santiago and Teja model, with overall average absolute relative deviations (AARDs) of 6.29%, 4.39%, 3.12% and 5.07%, respectively.

CONCLUSION

Oridonin exhibits retrograde solubility behaviour in the supercritical state. Fictitious solubility data were further determined and obtained a good fit with four semi-empirical models. Simultaneously, the values of the total heat of solution, vaporisation and solvation of oridonin were estimated. © 2016 Society of Chemical Industry.

Solvent Supercritical Fluid Technologies to Extract Bioactive Compounds from Natural Sources: A Review

Supercritical fluid technologies offer a propitious method for drug discovery from natural sources. Such methods require relatively short processing times, produce extracts with little or no organic co-solvent, and are able to extract bioactive molecules whilst minimising degradation. Supercritical fluid extraction (SFE) provides a range of benefits, as well as offering routes to overcome some of the limitations that exist with the conventional methods of extraction. Unfortunately, SFE-based methods are not without their own shortcomings; two major ones being: (1) the high establishment cost; and (2) the selective solvent nature of CO₂, i.e., that CO₂ only dissolves small non-polar molecules, although this can be viewed as a positive outcome provided bioactive molecules are extracted during solvent-based SFE. This review provides an update of SFE methods for natural products and outlines the main operating parameters for extract recovery. Selected processing considerations are presented regarding supercritical fluids and the development and application of ultrasonic-assisted SFE methods, as well as providing some of the key aspects of SFE scalability.

Extraction of α-humulene-enriched oil from clove using ultrasound-assisted supercritical carbon dioxide extraction and studies of its fictitious solubility

Clove buds are used as a spice and food flavoring. In this study, clove oil and α-humulene was extracted from cloves using supercritical carbon dioxide extraction with and without ultrasound assistance (USC-CO2 and SC-CO2, respectively) at different temperatures (32-50°C) and pressures (9.0-25.0MPa). The results of these extractions were compared with those of heat reflux extraction and steam distillation methods conducted in parallel. The extracts obtained using these four techniques were analyzed using gas chromatography and gas chromatography/mass spectrometry (GC/MS). The results demonstrated that the USC-CO2 extraction procedure may extract clove oil and α-humulene from clove buds with better yields and shorter extraction times than conventional extraction techniques while utilizing less severe operating parameters. Furthermore, the experimental fictitious solubility data obtained using the dynamic method were well correlated with density-based models, including the Chrastil model, the Bartle model and the Kumar and Johnston model.