Camellia nitidissima Chi leaf as pancreatic lipase inhibitors: Inhibition potentials and mechanism

Inhibition of pancreatic lipase by coffee leaves-derived polyphenols: A mechanistic study

The suppression of pancreatic lipase has been employed to mitigate obesity. This study explored the mechanism of coffee leaf extracts to inhibit pancreatic lipase. The ethyl acetate fraction derived from coffee leaves (EAC) exhibited the highest inhibitory capacity with a half-maximal inhibitory concentration (IC50) of 0.469 mg/mL and an inhibitor constant (Ki) of 0.185 mg/mL. This fraction was enriched with 3,5-dicaffeoylquinic acid (3,5-diCQA, 146.50 mg/g), epicatechin (87.51 mg/g), and isoquercetin (48.29 mg/g). EAC inhibited lipase in a reversible and competitive manner, and quenched its intrinsic fluorescence through a static mechanism. Molecular docking revealed that bioactive compounds in EAC bind to key amino acid residues (HIS-263, PHE-77, and SER-152) located within the active cavity of lipase. Catechin derivatives play a key role in the lipase inhibitory activity within EAC. Overall, our findings highlight the promising potential of coffee leaf extract as a functional ingredient for alleviating obesity through inhibition of lipase.

Inquiry lipaseoring the mechanism of pancreatic lipase inhibition by isovitexin based on multispectral method and enzyme inhibition assay

Isovitexin is a main natural flavonoid component in various plants. Currently, the inhibitory effect of isovitexin on pancreatic lipase (PL) and its mechanism have not been elucidated yet. In the present study, we investigated the inhibitory effect of isovitexin on PL, as well as its interaction mechanism, using enzyme inhibition methods, spectroscopic analysis, and molecular simulations. Results showed that isovitexin possessed significant PL inhibitory activity, with IC50 values of 0.26 ± 0.02 mM. The interaction between isovitexin and PL was dominated by static quenching, and mainly through hydrogen bonding and hydrophobic interaction forces. Analysis of fluorescence spectroscopy confirmed that isovitexin binding altered the conformation of the PL. Circular dichroism (CD) spectrum indicated that isovitexin altered the secondary structure of PL by decreasing the α-helix content and increasing the β-fold content. Molecular simulations further characterize the conformational changes produced by the interaction between isovitexin with PL. The performed study may provide a new insight into the inhibitory mechanism of isovitexin as a novel PL inhibitor.

Immobilization of Thermomyces lanuginosus lipase in a novel polysaccharide-based hydrogel by a two-step crosslinking method and its use in the lauroylation of α-arbutin

The Thermomyces lanuginosus lipase (TLLs) was successfully immobilized within a novel hydrogel matrix through a two-step crosslinking method. TLLs were initially crosslinked through the Schiff base reaction by oxidized carboxymethyl cellulose (OCMC). The water-soluble OCMC@TLLs complex was subsequently crosslinked by carboxymethyl chitosan (CMCSH) in a microfluidic apparatus to form the CMCHS/OCMC@TLLs microspheres. The CD (Circular Dichroism, CD) and FT-IR (Fourier Transform infrared spectroscopy, FT-IR) spectra demonstrated that the crosslinking of TLLs with OCMC resulted in a less significant impact on their structure compared to that with glutaraldehyde. CMCHS/OCMC@TLLs showed decreased catalytic performance due to the mass transfer resistance, while its thermal stability was greatly improved. The CMCHS/OCMC@TLLs were used to catalyze the lauroylation of arbutin in tetrahydrofuran. After 12 h of reaction under optimal conditions, the yield of 6'-O-lauryl arbutin reached an impressive 92.12%. The prepared 6'-O-lauryl arbutin has high lipophilicity and exhibits similar tyrosinase inhibitory activity and higher antioxidant activity compared to its parent compound.

Triterpenes and Pheophorbides from Camellia ptilosperma and Their Cytotoxicity, Photocytotoxicity, and Photodynamic Antibacterial Activity

Phytochemical investigation of the leaves of Camellia ptilosperma S. Y. Liang et Q. D. Chen led to the isolation of ten undescribed compounds, including six new triterpenes (1-6) and four new pheophorbide-related compounds (7-10). Meanwhile, the cytotoxic activity of the six triterpenes against six cancer cell lines was evaluated by MTT assay. Compound 2 showed potent cytotoxicity toward HepG2 cells with an IC50 value of 2.57 μM. Compounds 4 and 5 exhibited cytotoxicity against MDA-MB231 cells, with IC50 values of 11.31 and 5.52 μM, respectively. Additionally, the cytotoxicity of four new pheophorbides against these cancer cells was evaluated both in the presence and absence of light treatment. Compound 7 exhibited exceptional photocytotoxicity against Hela, MCF-7, and A549 cells, with IC50 values of 0.43 μM, 0.28 μM, and 0.92 μM, respectively. Compound 10 demonstrated significant photodynamic cytotoxic activity against BEL-7402 and HepG2 cells with IC50 values of 0.77 μM and 0.33 μM, respectively. The photodynamic antibacterial activity of 7-10 was also tested for S. aureus, E. coli, K. pneumoniae, and P. aeruginosa under direct illumination. Compounds 8 and 10 exhibited sensitivity to E. coli and demonstrated a photodynamic antibacterial effect, with a MIC value of 0.625 μM.

Identification of pancreatic lipase inhibitors from Eucommia ulmoides tea by affinity-ultrafiltration combined UPLC-Orbitrap MS and in vitro validation

Pancreatic lipase inhibitors can reduce blood lipids by inactivating the catalytic activity of human pancreatic lipase, a key enzyme involved in triglyceride hydrolysis, which helps control some dyslipidemic diseases. The ability of Eucommia ulmoides tea to improve fat-related diseases is closely related to the natural inhibitory components of pancreatic lipase contained in the tea. In this study, fifteen pancreatic lipase inhibitors were screened and identified from Eucommia ulmoides tea by affinity-ultrafiltration combined UPLC-Q-Exactive Orbitrap/MS. Four representative components of geniposidic acid, quercetin-3-O-sambuboside, isochlorogenic acid A, and quercetin with high binding degrees were further verified by nanoscale differential scanning fluorimetry (nanoDSF) and enzyme inhibitory assays. The results of flow cytometry showed that they could significantly reduce the activity of pancreatic lipase in AR42J cells induced by palmitic acid in a concentration-dependent manner. Our findings suggest that Eucommia ulmoides tea may be a promising resource for pancreatic lipase inhibitors of natural origin.

Genome Survey and SSR Analysis of Camellia nitidissima Chi (Theaceae)

Camellia nitidissima Chi (CNC), a species of golden Camellia, is well known as "the queen of camellias." It is an ornamental, medicinal, and edible plant grown in China. In this study, we conducted a genome survey sequencing analysis and simple sequence repeat (SSR) identification of CNC using the Illumina sequencing platform. The 21-mer analysis predicted its genome size to be 2,778.82 Mb, with heterozygosity and repetition rates of 1.42% and 65.27%, respectively. The CNC genome sequences were assembled into 9,399,197 scaffolds, covering ∼2,910 Mb and an N50 of 869 base pair. Its genomic characteristics were found to be similar to those of Camellia oleifera. In addition, 1,940,616 SSRs were identified from the genome data, including mono-(61.85%), di-(28.71%), tri-(6.51%), tetra-(1.85%), penta-(0.57%), and hexanucleotide motifs (0.51%). We believe these data will provide a useful foundation for the development of novel molecular markers for CNC as well as for further whole-genome sequencing of CNC.

Active fractions of golden-flowered tea (Camellia nitidissima Chi) inhibit epidermal growth factor receptor mutated non-small cell lung cancer via multiple pathways and targets in vitro and in vivo

As a medicine-food homology (MFH) plant, golden-flowered tea (Camellia nitidissima Chi, CNC) has many different pharmacologic activities and is known as "the queen of the tea family" and "the Panda of the Plant world". Several studies have revealed the pharmacologic effects of CNC crude extract, including anti-tumor, anti-oxidative and hepatoprotective activity. However, there are few studies on the anti-tumor active fractions and components of CNC, yet the underlying mechanism has not been investigated. Thus, we sought to verify the anti-non-small cell lung cancer (NSCLC) effects of four active fractions of CNC. Firstly, we determined the pharmacodynamic material basis of the four active fractions of CNC (Camellia. leave. saponins, Camellia. leave. polyphenols, Camellia. flower. saponins, Camellia. flower. polyphenols) by UPLC-Q-TOF-MS/MS and confirmed the differences in their specific compound contents. Then, MTT, colony formation assay and EdU incorporation assay confirmed that all fractions of CNC exhibit significant inhibitory on NSCLC, especially the Camellia. leave. saponins (CLS) fraction on EGFR mutated NSCLC cell lines. Moreover, transcriptome analysis revealed that the inhibition of NSCLC cell growth by CLS may be via three pathways, including "Cytokine-cytokine receptor interaction," "PI3K-Akt signaling pathway" and "MAPK signaling pathway." Subsequently, quantitative real-time PCR (RT-qPCR) and Western blot (WB) revealed TGFB2, INHBB, PIK3R3, ITGB8, TrkB and CACNA1D as the critical targets for the anti-tumor effects of CLS in vitro. Finally, the xenograft models confirmed that CLS treatment effectively suppressed tumor growth, and the key targets were also verified in vivo. These observations suggest that golden-flowered tea could be developed as a functional tea drink with anti-cancer ability, providing an essential molecular mechanism foundation for MFH medicine treating NSCLC.

Rapid Screening of Lipase Inhibitors from Ophiopogonis Radix Using High-Performance Thin Layer Chromatography by Two Step Gradient Elution Combined with Bioautographic Method

In this study, a high-performance thin layer chromatography (HPTLC) method by two step gradient elution with two mobile phases was developed for the simultaneous analysis of seven constituents in Ophiopogonis Radix. The chromatography was performed on silica gel 60 F₂₅₄ plate with dichloromethane-methanol-ethyl acetate-water (70:25:12:3, v/v/v/v) and dichloromethane-methanol (300:1, v/v) as the mobile phase for two step gradient elution. Then, the HPTLC profiles were observed after derivatization with 10% sulfuric acid in ethanol solution. The obtained HPTLC images were further analyzed by chemometric approaches and the samples could be clustered based on regions and/or growth years, which were two important factors affecting the constituents in Ophiopogonis Radix. Furthermore, five compounds including ophiopogonin D, ophiopojaponin C, ophiopogonin D’, ophiopogonin C’ and methylophiopogonanone B were screened as potential lipase inhibitors from Ophiopogonis Radix by the HPTLC-bioautographic method. The binding modes and interactions between the five compounds and lipase were further explored by molecular docking analysis. The developed HPTLC method could be used for quality control of Ophiopogonis Radix and screening of the potential lipase inhibitors.