Optimization of microwave-assisted extraction, antioxidant capacity, and characterization of total flavonoids from the leaves of Alpinia oxyphylla Miq

Methodological advances in formulation and assay of herbal resources-based topical drug delivery systems

Medicinal plants have been utilized for centuries as a source of healing compounds, which consist of thousands of known bioactive molecules with therapeutic potentials. This article aims to explore and emphasize the significance of medicinal plants and bioactive compounds in the development of topical pharmaceutical formulations. The journey from the extraction of phytochemicals to the development of topical pharmaceutical formulations is described with the aid of scientific evidence selected from PubMed, Google Scholar, ScienceDirect, and Web of Science. Articles published in English during 2018-2023 period were considered and selected randomly. The review discusses the extraction process of medicinal plants, solvent selection, and green synthesis of metal nanoparticles. Subsequently, various biological activities of plant extracts are elaborated especially focusing on antimicrobial, antioxidant, anti-inflammatory, and sun protection activities, along with the corresponding in vitro assays commonly employed for the evaluation. The article presents the process of compound isolation through bioactivity-guided fractionation and also the toxicity evaluation of isolated fractions. Finally, the formulation of medicinal plant extracts into topical pharmaceuticals is addressed, emphasizing the stability evaluation procedures necessary for ensuring product quality and efficacy.

Recent Research Progress on the Chemical Constituents, Pharmacology, and Pharmacokinetics of Alpinae oxyphyllae Fructus

Alpinae oxyphyllae fructus (AOF), the dried mature fruit of Alpinia oxyphylla Miquel of the Zingiberaceae family, shows many special pharmacological effects. In recent years, there has been an abundance of research results on AOF. In this paper, the new compounds isolated from AOF since 2018 are reviewed, including terpenes, flavonoids, diarylheptanoids, phenolic acid, sterols, alkanes, fats, etc. The isolation methods that were applied include the microwave-assisted method, response surface method, chiral high-performance liquid chromatography-multiple reaction monitoring-mass spectrometry (HPLC-MRM-MS) analytical method, ultra-high-performance liquid chromatography-quadrupole-electrostatic field orbitrap high-resolution mass spectrometry (UPLC-Orbitrap-HRMS) method, ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method, hot water leaching method, ethanol leaching method, and so on. Additionally, the pharmacological effects of AOF found from 2018 to 2024 are also summarized, including neuroprotection, regulation of metabolic disorders, antioxidant activity, antiapoptosis, antiinflammatory activity, antidiabetic activity, antihyperuricemia, antiaging, antidiuresis, immune regulation, anti-tumor activity, renal protection, hepatoprotection, and anti-asthma. This paper provides a reference for further research on AOF.

Flavonoids: Overview of Biosynthesis, Biological Activity, and Current Extraction Techniques

Recently, increased attention has been paid to natural sources as raw materials for the development of new added-value products. Flavonoids are a large family of polyphenols which include several classes based on their basic structure: flavanones, flavones, isoflavones, flavonols, flavanols, and anthocyanins. They have a multitude of biological properties, such as anti-inflammatory, antioxidant, antiviral, antimicrobial, anticancer, cardioprotective, and neuroprotective effects. Current trends of research and development on flavonoids relate to identification, extraction, isolation, physico-chemical characterization, and their applications to health benefits. This review presents an up-to-date survey of the most recent developments in the natural flavonoid classes, the biological activity of representative flavonoids, current extraction techniques, and perspectives.

Extraction and Purification of Flavonoids from Buddleja officinalis Maxim and Their Attenuation of H2O2-Induced Cell Injury by Modulating Oxidative Stress and Autophagy

Cataracts are an ailment representing the leading cause of blindness in the world. The pathogenesis of cataracts is not clear, and there is no effective treatment. An increasing amount of evidence shows that oxidative stress and autophagy in lens epithelial cells play a key role in the occurrence and development of cataracts. Buddleja officinalis Maxim flavonoids (BMF) are natural antioxidants and regulators that present anti-inflammatory and anti-tumor effects, among others. In this study, we optimized the extraction method of BMFs and detected three of their main active monomers (luteolin, apigenin, and acacetin). In addition, a model of oxidative damage model using rabbit lens epithelial cells induced by hydrogen peroxide (H2O2). By detecting the levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), and OH (OH), the expression of autophagosomes and autolysosomes were observed after MRFP-GFP-LC3 adenovirus was introduced into the cells. Western blotting was used to detect the expression of Beclin-1 and P62. Our research results showed that the optimal extraction parameters to obtain the highest yield of total flavonoids were a liquid−solid ratio of 1:31 g/mL, an ethanol volume fraction of 67%, an extraction time of 2.6 h, and an extraction temperature of 58 °C. Moreover, the content of luteolin was 690.85 ppb, that of apigenin was 114.91 ppb, and the content of acacetin was 5.617 ppb. After oxidative damage was induced by H2O2, the cell survival rate decreased significantly. BMFs could increase the levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and decrease the levels of malondialdehyde (MDA) and OH (OH). After the MRFP-GFP-LC3 virus was introduced into rabbit lens epithelial cells and detecting the expression of P62 and Beclin-1, we found that the intervention of BMF could promote the binding of autophagosomes to lysosomes. Compared with the model group, the level of P62 in the low-, middle-, and high-dose groups of BMF was significantly down-regulated, the level of Beclin-1 was significantly increased, and the difference was statistically significant (p < 0.05). In other words, the optimized extraction method was better than others, and the purified BMF contained three main active monomers (luteolin, apigenin, and acacetin). In addition, BMFs could ameliorate the H2O2-induced oxidative damage to rabbit lens cells by promoting autophagy and regulating the level of antioxidation.

Effects of Extraction Technique on the Content and Antioxidant Activity of Flavonoids from Gossypium Hirsutum linn. Flowers

Cotton is one of the Uyghur medical materials in China and is rich in flavonoids. Flavonoids have important pharmacological effects. The yield of flavonoids in traditional extraction methods is low, which affects the development of flavonoids. Therefore, it is urgent to optimize the extraction techniques. The yield of flavonoids in cotton flowers was effectively improved by response surface methodology, and the highest yield of flavonoids reached 5.66%, and the optimal extraction process conditions were obtained. The DPPH free radical scavenging rate, hydroxyl free radical scavenging rate, superoxide anion free radical scavenging rate, and reducing ability were tested to reflect the antioxidant capacity of flavonoids. The flavonoids had an excellent antioxidant effect. Cell experiments suggested that the flavonoids had the effect of protecting glutamate-induced damage to HT-22 cells. The results of this study provide a theoretical basis for the extraction of cotton flowers flavonoids and the comprehensive evaluation of antioxidant products, as well as the extraction of other plant flavonoids.

Effects of five extraction methods on total content, composition, and stability of flavonoids in jujube

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Five methods of extracting flavonoids from jujube were compared in different aspects.

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The extraction methods can significantly influence the flavonoid compositions.

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DES-UAE method had outstanding ability to maintain the stability of flavonoids.

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DES-UAE is an efficient and green method for extracting flavonoids from jujube.

The present study investigated the effects of different extraction methods including water-water bath (W-WB), ethanol-water bath (E-WB), deep eutectic solvent (DES) combined with ultrasound-assisted extraction (DES-UAE), microwave-assisted extraction (DES-MAE), and enzyme-assisted extraction (DES-EAE) on flavonoids (total flavonoid content, flavonoid composition, and stability) in jujube. The highest total flavonoid content of 8.03 mg/g was obtained by the DES-MAE extraction. Fifteen types of flavonoids were identified from jujube. The amount of rutin produced by the E-WB and DES-UAE methods was 66.88 ± 1.58 μg/g and 45.23 ± 3.22 μg/g, respectively. The retention of flavonoids in DES-UAE extracts were 98.15 ± 0.51%, 64.25 ± 2.21% after 2 h of high temperature treatment at 90 °C and 21 days of dark storage, respectively. The flavonoids extracted by different methods were suitable for dark storage under different light contrasts, where the retention of flavonoids extracted by DES-UAE method was 86.44 ± 2.45%. In conclusion, DES-UAE would be an efficient method for flavonoid extraction from jujube.

Preparation and Recognition Properties of Molecularly Imprinted Nanofiber Membrane of Chrysin

The separation and extraction of chrysin from active ingredients of natural products are of great significance, but the existing separation and extraction methods have certain drawbacks. Here, chrysin molecularly imprinted nanofiber membranes (MINMs) were prepared by means of electrospinning using chrysin as a template and polyvinyl alcohol and natural renewable resource rosin ester as membrane materials, which were used for the separation of active components in the natural product. The MINM was examined using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The adsorption performance, adsorption kinetics, adsorption selectivity, and reusability of the MINM were investigated in static adsorption experiments. The analysis results show that the MINM was successfully prepared with good morphology and thermal stability. The MINM has a good adsorption capacity for chrysin, showing fast adsorption kinetics, and the maximum adsorption capacity was 127.5 mg·g⁻¹, conforming to the Langmuir isotherm model and pseudo-second-order kinetic model. In addition, the MINM exhibited good selectivity and excellent reusability. Therefore, the MINM proposed in this paper is a promising material for the adsorption and separation of chrysin.

Optimization of Flavonoid Extraction from Xanthoceras sorbifolia Bunge Flowers, and the Antioxidant and Antibacterial Capacity of the Extract

In the present work, the extraction process of total flavonoids (TFs) from X. sorbifolia flowers by ultrasound-assisted extraction was optimized under the response surface methodology (RSM) on the basis of single-factor experiments. The optimal extraction conditions were as follows: ethanol concentration of 80%, solid–liquid ratio of 1:37 (g/mL), temperature of 84 °C, and extraction time of 1 h. Under the optimized conditions, the extraction yield of the TFs was 3.956 ± 0.04%. The radical scavenging capacities of TFs against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) were much greater than that of rutin. The results of antibacterial experiments indicated that the TFs displayed strong inhibitory activities on E. coli, S. aureus and Bacillus subtilis. Therefore, X. sorbifolia flowers can be used as a novel source of natural flavonoids, and the TFs have potential applications as natural antioxidants or antibacterial agents in the food and pharmaceutical industries.

Analysis of Bioactive Components in the Fruit, Roots, and Leaves of Alpinia oxyphylla by UPLC-MS/MS

Alpinia oxyphylla (A. oxyphylla) fruit has long been used in traditional Chinese medicine. In our study, the bioactive components of its roots, fruit, and leaves were investigated, and their potential medical value was predicted. The root, fruit, and leaf samples were analyzed using a UPLC-MS/MS system. The mass spectrometry outcomes were annotated by MULTIAQUANT. The “compound-disease targets” were used to construct a pharmacology network. A total of 293, 277, and 251 components were identified in the roots, fruit, and leaves, respectively. The fruit of A. oxyphylla had a higher abundance of flavonols. The roots of A. oxyphylla were enriched in flavonols and phenolic acids. The leaves of A. oxyphylla exhibited high contents of flavonols, phenolic acids, and tannins. Furthermore, network pharmacology analysis showed that flavonoids are the most important effectors in the fruit of A. oxyphylla and phenolic acids are the most important effectors in the roots and leaves. Moreover, the results suggested that the tissues of A. oxyphylla might play a role in the regulation of disease-related genes. The whole plant of A. oxyphylla is rich in natural drug components, and each tissue has high medicinal value. Therefore, comprehensive utilization of A. oxyphylla can greatly improve its economic value.

Comparative transcriptome analysis of Alpinia oxyphylla Miq. reveals tissue-specific expression of flavonoid biosynthesis genes

BACKGROUND

Alpinia oxyphylla Miq. is an important edible and medicinal herb, and its dried fruits are widely used in traditional herbal medicine. Flavonoids are one of the main chemical compounds in A. oxyphylla; however, the genetic and molecular mechanisms of flavonoid biosynthesis are not well understood. We performed transcriptome analysis in the fruit, root, and leaf tissues of A. oxyphylla to delineate tissue-specific gene expression and metabolic pathways in this medicinal plant.

RESULTS

In all, 8.85, 10.10, 8.68, 6.89, and 8.51 Gb clean data were obtained for early-, middle-, and late-stage fruits, leaves, and roots, respectively. Furthermore, 50,401 unigenes were grouped into functional categories based on four databases, namely Nr (47,745 unigenes), Uniprot (49,685 unigenes), KOG (20,153 unigenes), and KEGG (27,285 unigenes). A total of 3110 differentially expressed genes (DEGs) and five distinct clusters with similar expression patterns were obtained, in which 27 unigenes encoded 13 key enzymes associated with flavonoid biosynthesis. In particular, 9 DEGs were significantly up-regulated in fruits, whereas expression of 11 DEGs were highly up-regulated in roots, compared with those in leaves.

CONCLUSION

The DEGs and metabolic pathway related to flavonoids biosynthesis were identified in root, leaf, and different stages of fruits from A. oxyphylla. These results provide insights into the molecular mechanism of flavonoid biosynthesis in A. oxyphylla and application of genetically engineered varieties of A. oxyphylla.

Sweet Cherry Byproducts Processed by Green Extraction Techniques as a Source of Bioactive Compounds with Antiaging Properties

In the cosmetic industry, there is a continuous demand for new and innovative ingredients for product development. In the context of continual renovation, both cosmetic companies and customers are particularly interested in compounds derived from natural sources due to their multiple benefits. In this study, novel and green-extractive techniques (pressurized solvent, supercritical CO₂, and subcritical water extractions) were used to obtain three new extracts from sweet cherry stems, a byproduct generated by the food industry. The extracts were characterized by high-performance liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS), and 57 compounds, mainly flavonoids but also organic and phenolic acids, fatty acids, and terpenes, were identified. After analytical characterization, a multistep screening approach, including antioxidant, enzymatic, and photoprotective cellular studies, was used to select the best extract according to its benefits of interest to the cosmetics industry. The extract obtained with supercritical CO₂ presented the best characteristics, including a wide antioxidant capacity, especially against lipid peroxyl and ^•OH free radicals, as well as relevant photoprotective action and antiaging properties, making it a potential new ingredient for consideration in the development of new cosmetics.