Gypenosides exert cardioprotective effects by promoting mitophagy and activating PI3K/Akt/GSK-3β/Mcl-1 signaling

Background

Gynostemma pentaphyllum (Thunb.) Makino, a well-known edible and medicinal plant, has anti-aging properties and is used to treataging-associated conditions such as diabetes, metabolic syndrome, and cardiovascular diseases. Gypenosides (GYPs) are the primary constituents of G. pentaphyllum. Increasing evidence indicates that GYPs are effective at preserving mitochondrial homeostasis and preventing heart failure (HF). This study aimed to uncover the cardioprotective mechanisms of GYPs related to mitochondrial regulation.

Methods

The bioactive components in GYPs and the potential targets in treating HF were obtained and screened using the network pharmacology approach, followed by drug-disease target prediction and enrichment analyses. The pharmacological effects of GYPs in cardioprotection, mitochondrial function, mitochondrial quality control, and underlying mechanisms were further investigated in Doxorubicin (Dox)-stimulated H9c2 cardiomyocytes.

Results

A total of 88 bioactive compounds of GYPs and their respective 71 drug-disease targets were identified. The hub targets covered MAPK, EGFR, PI3KCA, and Mcl-1. Enrichment analysis revealed that the pathways primarily contained PI3K/Akt, MAPK, and FoxO signalings, as well as calcium regulation, protein phosphorylation, apoptosis, and mitophagy process. In Dox-stimulated H9c2 rat cardiomyocytes, pretreatment with GYPs increased cell viability, enhanced cellular ATP content, restored basal oxygen consumption rate (OCR), and improved mitochondrial membrane potential (MMP). Furthermore, GYPs improved PINK1/parkin-mediated mitophagy without influencing mitochondrial fission/fusion proteins and the autophagic LC3 levels. Mechanistically, the phosphorylation of PI3K, Akt, GSK-3β, and the protein level of Mcl-1 was upregulated by GYP treatment.

Conclusion

Our findings reveal that GYPs exert cardioprotective effects by rescuing the defective mitophagy, and PI3K/Akt/GSK-3β/Mcl-1 signaling is potentially involved in this process.

Isolation and purification of high polar glycosides from aerial parts of Gynostemma pentaphyllum (Thunb.) Makino by linear gradient counter-current chromatography coupled with inner-recycling mode

Gynostemma pentaphyllum (Thunb.) Makino represents the popular health food and supplemental product with broad pharmacological activities. The highly polar glycosides, including flavonoids and saponins, are major effective active components that contain diverse sugar positions and quantities, which result in diverse chemical polarities, making it challenging to separate and isolate these components. The present work described the rapid and efficient linear gradient counter-current chromatography to preparatively separate glycosides from aboveground parts of G. pentaphyllum. Besides, the ethyl acetate and n-butanol binary mobile phases were achieved through adjusting associated proportions. Six glycosides, including quercetin-3-O-neohesperidoside (1), kaempferol-3-O-robinobioside (2), kaempferol-3-O-neohesperidoside (3), gypenoside LVI (4), ginsenoside Rb3 (5), and gypenoside XLVI (6), were isolated at the purities greater than 98%. Moreover, electrospray ionization mass spectrometry and nuclear magnetic resonance tandem mass spectrometry were conducted for structural identification. According to our findings, the established linear gradient counter-current chromatography was an efficient approach to separate the highly polar glycosides from aboveground parts of G. pentaphyllum. Our proposed strategy can be used to separate active compounds from other complex natural products.

Optimization, extraction, and purification of three bioactive compounds from Entada phaseoloides by high-speed countercurrent chromatography

The objective of this paper was to develop a preparative method for the separation and purification of phaseoloidin, entadamide A, and entadamide A-β-D-glucopyranoside from the crude extract of Entada phaseoloides by high-speed countercurrent chromatography (HSCCC) for the first time. Optimized by orthogonal experiments, the extraction conditions were extraction temperature of 65°C, solid-to-liquid ratio of 1:15 (g/mL), ethanol concentration of 40%, and extraction time of 2.5 h. Using n-butanol-acetic acid-water (4:1:5, v/v/v) as the two-phase solvent system, 38.79 mg phaseoloidin (the purity was 99.3% with a recovery of 98.1%), 34.85 mg entadamide A (the purity was 96.4% with a recovery of 98.5%), and 33.97 mg entadamide A-β-D-glucopyranoside (the purity was 98.6% with a recovery of 97.7%) were obtained from 500 mg crude extract by HSCCC in head-to-tail elution mode. The retention ratio of stationary phase was 51.0%. According to the antioxidant activity assays, phaseoloidin, entadamide A, and entadamide A-β-D-glucopyranoside had certain scavenging abilities on 1,1-diphenyl-2-picrylhydrazyl free radicals and hydroxyl free radicals.

Preparative Isolation and Purification of Calycosin and Formononetin from Astragali Radix using Hydrolytic Extraction Combined with High Speed Countercurrent Chromatography

Calycosin and formononetin were efficiently extracted from Astragali Radix and purified by high-speed countercurrent chromatography. Calycosin and formononetin could be hydrolyzed from calycosin-7-glucoside and ononin, respectively. The best extraction conditions were realized by single factor and orthogonal experiments, which were 100% ethanol, 2.5 mol/L hydrochloric acid, 1:40 ratio of solid to liquid, extracted 2 h and one time. The two-phase solvent system of n-hexane-ethyl acetate-ethanol-water (3:5:3:5, v/v) was selected for the purification of calycosin, and 1.3 mg calycosin (the purity was 95.8% and the recovery was 85.9%) was obtained from 264.9-mg crude extraction. The two-phase solvent system of n-hexane-ethyl acetate-ethanol-water (4:5:4:5, v/v) was selected for the purification of formononetin, and 2.0 mg formononetin (the purity was 98.9% and the recovery was 84.4%) was obtained from 248.9-mg crude extraction. Their structures were identified by HPLC, melting points, UV, FTIR, ESI-MS, 1H NMR and 13C NMR spectrum. According to the antioxidant activity assay, the scavenging abilities of calycosin to 1,1-diphenyl-2-picrylhydrazyl and hydroxyl free radicals (·OH) were stronger. The scavenging effect of formononetin was not demonstrated.

Purification of Four Caffeoylquinic Acid Derivatives from the Flowers of Gynura Procumbens by HSCCC

Four caffeoylquinic acid derivatives from the Gunura procumbens flowers (GPF) were successfully isolated and purified by high-speed counter-current chromatography (HSCCC). Ethyl acetate-methanol-water (3:1:3, v/v/v) was the optimum biphasic solvent system, which was selected by high-performance liquid chromatography (HPLC) and run on a preparative scale where the lower aqueous phase was used as the mobile phase with a head-to-tail elution mode. Chlorogenic acid (3.83 mg), Isochlorogenic acid A (6.51 mg), Isochlorogenic acid B (4.38 mg) and Isochlorogenic acid C (4.47 mg) were obtained for the first time in an one-step HSCCC separation from 800 mg of the crude extracts. The purities of four compounds were determined to be >95% by HPLC. Chemical structures of each isolated compounds were identified by nuclear magnetic resonance and electrospray ionization mass spectrometry methods. It is worth noting that all the four compounds were isolated here for the first time from GPF and this work confirms the effectiveness of HSCCC for the separation of compounds contained in complex samples, and provides a foundation for further exploitation of G. procumbens.

Preparative separation of liquiritigenin and glycyrrhetic acid from Glycyrrhiza uralensis Fisch using hydrolytic extraction combined with high-speed countercurrent chromatography

The objective of this paper was to develop a preparative method for the isolation and purification of liquiritigenin and glycyrrhetic acid from Glycyrrhiza uralensis Fisch using hydrolytic extraction combined with high-speed countercurrent chromatography (HSCCC). Liquiritigenin and glycyrrhetic acid were well hydrolyzed from liquiritin and glycyrrhizic acid by hydrochloric acid, respectively. The optimal extraction conditions were obtained by single-factor and orthogonal experiments, which were 100% ethanol, 1.5 mol/L hydrochloric acid, 1:25 ratio of solid to liquid, and extracted 2 h for one time. Using the two-phase solvent system of n-hexane-ethyl acetate-methanol-water (4:5:4:5, v/v), 2.1 mg liquiritigenin (the purity was 96.5% with a recovery of 87.6%) and 12.3 mg glycyrrhetic acid (the purity was 97.1% with a recovery of 74.4%) were obtained from 315-mg crude extraction by HSCCC. The retention ratio of stationary phase was 47.2%. Their structures were identified by HPLC, melting points, UV, Fourier-transform infrared, Electrospray ionization-MS, ¹ H nuclear magnetic resonance (NMR), and ¹³ C NMR spectra. According to the antioxidant activity assays, liquiritigenin and glycyrrhetic acid had some scavenging abilities on 1,1-diphenyl-2-picrylhydrazyl free radicals; liquiritigenin had stronger scavenging ability on hydroxyl radicals.

Bioassay-guided isolation and identification of anticancer and antioxidant compounds from Gynostemma pentaphyllum (Thunb.) Makino

Gynostemma pentaphyllum (Thunb.) Makino is a medicinal and edible plant in China whose buds and leaves are used for making a popular kind of tea drink. The anticancer and antioxidant properties of the ethyl acetate (EA) and n-butanol (n-Bu) fractions provide a basis for conducting experiments for isolation and identification of key compounds that may be responsible for the aforementioned properties of G. pentaphyllum. Four compounds were isolated from the two fractions using ODS packing column, silica gel column, polyamide column, Sephadex LH-20 gel column and HPLC. With the aid of ¹H, ¹³C NMR and mass spectrometry, they were identified as 3,4-dihydroxy phenyl-O-β-d-glucoside, gypenoside XLVI, gypenoside L and ginsenoside Rd. 3,4-Dihydroxy phenyl-O-β-d-glucoside showed the strongest DPPH (97.23%) and ABTS (101.37%) scavenging effect and ferric ion reducing power (FRAP value 0.8846), which may be closely related to the hydrogen atoms of phenolic hydroxyls. Gypenoside L and ginsenoside Rd displayed the highest inhibition of tumor cell proliferation of A549 and MCF-7 cell lines, which had to do with the chemical structure of the compounds bearing glycosylated parts and free hydroxyls at the 20th or 21st carbon atom of dammarane-type saponin.

Gynostemma pentaphyllum (Thunb.) Makino is a medicinal and edible plant in China whose buds and leaves are used for making a popular kind of tea drink.

Microwave-Assisted Extraction of Natural Antioxidants from the Exotic Gordonia axillaris Fruit: Optimization and Identification of Phenolic Compounds

Our previous study reported that the fruit of Gordonia axillaris , an edible wild fruit, possessed strong antioxidant activity. In this study, a microwave-assisted extraction (MAE) method was established to extract antioxidants from the fruit of Gordonia axillaris . The influence of five parameters, including ethanol concentration, solvent/material ratio, extraction time, extraction temperature and microwave power, was investigated by single-factor experiments. Three factors, namely ethanol concentration, solvent/material ratio, extraction time, were found to exert a major influence on extraction efficacy, and were further studied by response surface methodology to investigate their interactions. Ethanol concentration of 36.89%, solvent/material ratio of 29.56 mL/g, extraction time of 71.04 min, temperature of 40 °C, and microwave power of 400 W were found to be the optimal condition. The TEAC value was 198.16 ± 5.47 µmol Trolox/g DW under the optimal conditions, which was in conformity to the predicted value (200.28 µmol Trolox/g DW). In addition, the MAE method was compared with two conventional methods (Soxhlet extraction and maceration extraction). Results showed that the antioxidant capacity of the extract obtained by MAE method was stronger than that obtained by maceration (168.67 ± 3.88 µmol Trolox/g DW) or Soxhlet extraction (114.09 ± 2.01 µmol Trolox/g DW). Finally, several phenolic compounds in the extract were identified and quantified by UPLC-MS/MS, which were rutin, gallic acid, protocatechuic acid, epicatechin, epicatechin gallate, 2-hydrocinnamic acid, p -coumaric acid, quercetin, chlorogenic acid and ferulic acid.