Cancer chemopreventive theasaponin derivatives from the total tea seed saponin of Camellia sinensis

Isolation and identification of triterpenoid saponins with antiproliferative and hemolytic activities from Camellia oleifera Abel seeds

Seven previously undescribed triterpenoid saponins, oleiferasaponins G1-G7 (1-7), along with two known congeners (8 and 9) were isolated from seeds of Camellia oleifera Abel. Their structures were determined by extensive spectroscopic data. All isolated compounds are decorated with an aglycone and tetrasaccharide moiety. Compounds 1-5 were characterized by an uncommon acylation at C-16 instead of hydroxylation among the identified triterpenoid saponins in Camellia plants. Importantly, compounds 6-9 exhibited excellent antiproliferation effects against HCT-116, HL-60 and HepG2. According to preliminary structure-activity relationship investigations, a free hydroxyl group at the C-16 position of saponins was beneficial for their antiproliferation activity. Interestingly, compounds 1-5 displayed neither antiproliferation nor hemolytic activity, which suggests that the hemolytic and antiproliferation activity of the test saponins exhibit a relatively consistent pattern in their structure-activity relationships.

Non-antibiotic feed additives production by Acremonium terricola solid-fermented Camellia oleifera meal

The Camellia oleifera meal (COM), a primary byproduct of oil-tea processing, often being discarded or used as a low-grade fertilizer due to its low value. The underutilization has become a significant bottleneck hindering the high-quality development of the oil-tea industry. In this study, the production of antibiotic-free feed additives through the solid-state fermentation of COM by Acremonium terricola was investigated. Our findings revealed that a saponin concentration of 5 mg/mL significantly enhanced the production of cordycepic acid (70.4 mg/g), ergosterol (3.32 mg/g), and chitin (110 mg/g) by A. terricola. This concentration also promoted chitin production and the activities of peroxidase (POD) and Na+/K+-ATPase, thereby maintaining cellular homeostasis and energy balance in A. terricola. Solid-state fermented rice bran (RB), wheat bran (WB), and desaponificated COM (containing 2.6 mg/100 g of tea saponin) were all found to be beneficial for increasing the production of cordycepic acid and ergosterol. The blend of COM, RB, and WB in the ratio of 15:65:20 was particularly advantageous for the production and accumulation of cordycepic acid and ergosterol, yielding 1.54 and 1.43 times, 1.27 and 1.37 times, and 1.98 and 5.52 times more than those produced by WB, RB, and COM alone, respectively.Meantime, the difference in contents of sugar and protein in A. terricola cultures (ATCs) using combination were not significant compared to RB and WB. These results indicated that COM can partially replace foodstuffs or food by-products to prepare antibiotic-free feed additives by A. terricola.

Isolation and microbial transformation of tea sapogenin from seed pomace of Camellia oleifera with anti-inflammatory effects

In the current study, tea saponin, identified as the primary bioactive constituent in seed pomace of Camellia oleifera Abel., was meticulously extracted and hydrolyzed to yield five known sapogenins: 16-O-tiglogycamelliagnin B (a), camelliagnin A (b), 16-O-angeloybarringtogenol C (c), theasapogenol E (d), theasapogenol F (e). Subsequent biotransformation of compound a facilitated the isolation of six novel metabolites (a1-a6). The anti-inflammatory potential of these compounds was assessed using pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns molecules (DAMPs)-mediated cellular inflammation models. Notably, compounds b and a2 demonstrated significant inhibitory effects on both lipopolysaccharide (LPS) and high-mobility group box 1 (HMGB1)-induced inflammation, surpassing the efficacy of the standard anti-inflammatory agent, carbenoxolone. Conversely, compounds d, a3, and a6 selectivity targeted endogenous HMGB1-induced inflammation, showcasing a pronounced specificity. These results underscore the therapeutic promise of C. oleifera seed pomace-derived compounds as potent agents for the management of inflammatory diseases triggered by infections and tissue damage.

The MADS-box transcription factor CsAGL9 plays essential roles in seed setting in Camellia sinensis

The number of seed setting (NSS) is an important biological trait that affects tea propagation and yield. In this study, the NSS of an F1 tea population (n = 324) generated via a cross between 'Longjing 43' and 'Baihaozao' was investigated at two locations in two consecutive years. Quantitative trait locus (QTL) mapping of the NSS was performed, and 10 major QTLs were identified. In total, 318 genes were found in these 10 QTLs intervals, and 11 key candidate genes were preliminarily identified. Among them, the MADS-box transcription factor AGAMOUS LIKE 9 (CsAGL9, CSS0037962) located in the most stable QTL (qNSS2) was identified as a key gene affecting the NSS. CsAGL9 overexpression in Arabidopsis promoted early flowering and significantly decreased the length and number of pods and number of seeds per pod. Transcriptome analysis demonstrated that the auxin pathway, a key hormone pathway regulating plant reproduction, was highly affected in the transgenic lines. The auxin pathway was likewise the most prominent in the gene co-expression network study of CsAGL9 in tea plants. In summary, we identified CsAGL9 is essential for seed setting using QTL mapping integrated with RNA-seq, which shed a new light on the mechanism NSS of seed setting in tea plants.

Extraction optimization of tea saponins from Camellia oleifera seed meal with deep eutectic solvents: Composition identification and properties evaluation

Traditional organic solvent extractions of tea saponins have many drawbacks. This study aimed to establish an environment-friendly and efficient technology based on deep eutectic solvents (DESs) to extract tea saponins from Camellia oleifera seed meal. The solvent consisting of choline chloride and methylurea was screened as optimal DES. Under the optimal extraction conditions obtained by response surface methodology, the extraction yield of tea saponins reached 94.36 mg/g, which increased by 27% compared with ethanol extraction, while the extraction time was reduced by 50%. Analysis of UV, FT-IR, and UPLC-Q/TOF-MS indicated tea saponins did not alter during DES extraction. Surface activity and emulsification evaluation showed that extracted tea saponins could reduce interfacial tension at the oil-water interface with excellent foamability and foam stability, and they could form nanoemulsions (d₃₂ < 200 nm) with excellent stability. This study provides a suitable approach for the efficient extraction of tea saponins.

Anti-Candida albicans Effects and Mechanisms of Theasaponin E1 and Assamsaponin A

Candida albicans is an opportunistic human fungal pathogen, and its drug resistance is becoming a serious problem. Camellia sinensis seed saponins showed inhibitory effects on resistant Candida albicans strains, but the active components and mechanisms are unclear. In this study, the effects and mechanisms of two Camellia sinensis seed saponin monomers, theasaponin E1 (TE1) and assamsaponin A (ASA), on a resistant Candida albicans strain (ATCC 10231) were explored. The minimum inhibitory concentration and minimum fungicidal concentration of TE1 and ASA were equivalent. The time-kill curves showed that the fungicidal efficiency of ASA was higher than that of TE1. TE1 and ASA significantly increased the cell membrane permeability and disrupted the cell membrane integrity of C. albicans cells, probably by interacting with membrane-bound sterols. Moreover, TE1 and ASA induced the accumulation of intracellular ROS and decreased the mitochondrial membrane potential. Transcriptome and qRT-PCR analyses revealed that the differentially expressed genes were concentrated in the cell wall, plasma membrane, glycolysis, and ergosterol synthesis pathways. In conclusion, the antifungal mechanisms of TE1 and ASA included the interference with the biosynthesis of ergosterol in fungal cell membranes, damage to the mitochondria, and the regulation of energy metabolism and lipid metabolism. Tea seed saponins have the potential to be novel anti-Candida albicans agents.

Characterization of triterpenoids as possible bitter-tasting compounds in teas infected with bird’s eye spot disease

Tea infected with bird's eye spot disease generally imparts a long-lasting bitter taste, which is unacceptable to most consumers. This study has comprehensively evaluated the taste profiles of infected and healthy teas and investigated their known bitter compounds previously reported in tea. Quantification analyses and calculation of dose-over-threshold (DoT) factors revealed that no obvious difference was visualized in catechins, caffeine, bitter amino acids, and flavonols and their glycosides between infected and healthy tea samples, which was also verified by principal component analysis (PCA) and hierarchical cluster analysis (HCA). Therefore, these known bitter compounds have been ruled out as critical contributors to the long-lasting bitterness of infected teas. Furthermore, Gel permeation chromatography, sensory analysis, and UPLC-Q-TOF-MS were employed and identified 13 substances from the target bitter fractions, including caffeine, ten triterpenoids, and two oxylipins. The higher triterpenoid levels were supposed to be the reason causing the long-lasting bitterness. This study has provided a research direction for the molecular basis of the long-lasting bitterness of infected tea leaves with bird's eye spot disease.

Integrating metabolite and transcriptome analysis revealed the different mechanisms of characteristic compound biosynthesis and transcriptional regulation in tea flowers

The flowers of tea plants (Camellia sinensis), as well as tea leaves, contain abundant secondary metabolites and are big potential resources for the extraction of bioactive compounds or preparation of functional foods. However, little is known about the biosynthesis and transcriptional regulation mechanisms of those metabolites in tea flowers, such as terpenoid, flavonol, catechins, caffeine, and theanine. This study finely integrated target and nontarget metabolism analyses to explore the metabolic feature of developing tea flowers. Tea flowers accumulated more abundant terpenoid compounds than young leaves. The transcriptome data of developing flowers and leaves showed that a higher expression level of later genes of terpenoid biosynthesis pathway, such as Terpene synthases gene family, in tea flowers was the candidate reason of the more abundant terpenoid compounds than in tea leaves. Differently, even though flavonol and catechin profiling between tea flowers and leaves was similar, the gene family members of flavonoid biosynthesis were selectively expressed by tea flowers and tea leaves. Transcriptome and phylogenetic analyses indicated that the regulatory mechanism of flavonol biosynthesis was perhaps different between tea flowers and leaves. However, the regulatory mechanism of catechin biosynthesis was perhaps similar between tea flowers and leaves. This study not only provides a global vision of metabolism and transcriptome in tea flowers but also uncovered the different mechanisms of biosynthesis and transcriptional regulation of those important compounds.

Comprehensive evaluation on tailor-made deep eutectic solvents (DESs) in extracting tea saponins from seed pomace of Camellia oleifera Abel

Tea saponins from Camellia oleifera Abel. seed pomace are new sources of commercial saponins. This study established an eco-friendly and efficient extraction method for tea saponins from C. oleifera seed pomace. A ternary deep eutectic solvent (DES) composed of l-proline, glycerol and sucrose (4:10:1 in molar ratio, abbreviated as PGS-5) achieved the highest extraction yield of tea saponins among all screened DESs. A maximum extraction yield of 23.22 ± 0.28% was obtained using PGS-5 under the optimized extraction time, DES concentration and liquid-solid ratio. Through ultraviolet, Fourier transform infrared spectroscopy and ultrahigh-performance liquid chromatography-Q Exactive HF mass spectroscopy, as well as analyses of antioxidant and antimicrobial activities, it was determined that extracted saponins did not altered during processing. Therefore, PGS-5 can serve as a solvent to obtain stable and beneficial tea saponins from C. oleifera seed pomace.

Triterpenoid saponins in tea (Camellia sinensis) plants: biosynthetic gene expression, content variations, chemical identification and cytotoxicity

Very little is known about saponins in tea and their biosynthesis in tea plants despite of the importance. Here, we studied tea saponins and their biosynthesis genes. Saponins were promptly recovered in tea infusions. Cytotoxicity of tea saponin extracts on human tongue squamous and hepatocellular carcinoma lines showed respective IC50 values of 29.2 and 17.5 μg/mL, which may be attributable to over 40 saponins identified in green tea. Saponin contents varied in shoot tips of 42 tea plant varieties but did not change drastically during tea processing. Saponin biosynthetic gene expression was consistent with its contents in plant tissues. Thus, plant tips produce significant amounts of saponins, which are stable during tea processing, and ready to be recovered to tea infusions to provide potent health benefits to consumers. This study paves a road towards clarifying the biosynthesis and genetic improvement of saponins in tea plants.

Purified Tea (Camellia sinensis (L.) Kuntze) Flower Saponins Induce the p53-Dependent Intrinsic Apoptosis of Cisplatin-Resistant Ovarian Cancer Cells

Ovarian cancer is currently ranked at fifth in cancer deaths among women. Patients who have undergone cisplatin-based chemotherapy can experience adverse effects or become resistant to treatment, which is a major impediment for ovarian cancer treatment. Natural products from plants have drawn great attention in the fight against cancer recently. In this trial, purified tea (Camellia sinensis (L.) Kuntze) flower saponins (PTFSs), whose main components are Chakasaponin I and Chakasaponin IV, inhibited the growth and proliferation of ovarian cancer cell lines A2780/CP70 and OVCAR-3. Flow cytometry, caspase activity and Western blotting analysis suggested that such inhibitory effects of PTFSs on ovarian cancer cells were attributed to the induction of cell apoptosis through the intrinsic pathway rather than extrinsic pathway. The p53 protein was then confirmed to play an important role in PTFS-induced intrinsic apoptosis, and the levels of its downstream proteins such as caspase families, Bcl-2 families, Apaf-1 and PARP were regulated by PTFS treatment. In addition, the upregulation of p53 expression by PTFSs were at least partly induced by DNA damage through the ATM/Chk2 pathway. The results help us to understand the mechanisms underlying the effects of PTFSs on preventing and treating platinum-resistant ovarian cancer.

Green Tea Seed Isolated Saponins Exerts Antibacterial Effects against Various Strains of Gram Positive and Gram Negative Bacteria, a Comprehensive Study In Vitro and In Vivo

Bacteria are one of the major causes of severe infections and diseases of plants and animals. Salmonella are crucially important due to infection in poultry leading to huge economical loses. Due to high cost and microbial resistance to the currently available chemical antibiotics, demand of screening natural products with antibiotics effects is increased. Plants are rich sources of natural bioactive compounds with antibiotic effects. Saponins are natural compounds of plant sources having a diverse range of applications. In present study we investigated the in vitro and in vivo antibacterial activities of green tea seed extracted saponins. Green tea seeds crude extract was prepared in 70% ethanol by continuous reflux in heating mantel for 5 hours. Crude saponins were extracted from the crude ethanolic extract of green tea seed by column chromatography using macroporous resin (D101). Saponin mixture in fraction 1 (Fr1) was obtained from crude saponins extract via column chromatography. Fr2 and Fr3 were isolated from saponins mixture by preparative HPLC. Antibacterial activities of the isolated saponins fractions were investigated against Escherichia coli (ATCC 25922), Streptococcus aureus (ATCC 12600), and six serovars of Salmonella. In vitro antibacterial activities were determined by disc-diffusion method and growth inhibition in liquid culture using 96-well plate. Results showed that the green tea isolated saponins fractions possess antibacterial effects in the following order Fr1>Fr2>Fr3. Antibacterial mechanism of saponins was elucidated by cell wall and membrane damaging potential of saponins determined by measuring AKP and soluble proteins levels. Fr1 was further used for in vivo antibacterial activities. Five-week grown chickens were selected for in vivo work, divided into three groups as control, infected, and treatment groups. Infected and treatment groups chickens were infected with bacteria and only treatment group chickens were treated with saponins. The qRT- PCR analysis of the blood and feces samples of the different groups' animals shows the presence of bacteria only in infected group while reduced expression levels of the bacterial pathogens were found in the samples of treatment group. Our results demonstrated that the green tea seed saponins used in this study possess strong antibacterial activities.

Saponins from seeds of Genus Camellia: Phytochemistry and bioactivity

Camellia seeds have been traditionally used as oil raw materials in Asia, and are known for a wide spectrum of applications. Oleanane-type triterpene saponins are the major specialised metabolites in Camellia seeds, and more than seventy saponins have been isolated and characterized. These natural compounds have caught much attention due to their various biological and pharmacological activities, including modulation of gastrointestinal system, anti-cancer, anti-inflammation, anti-microorganism, antioxidation, neuroprotection, hypolipidemic effects, foaming and detergence, as well as helping the accumulation of pollutants by plants. These compounds have a promising application in medicine, agriculture, industry and environmental protection. The present paper summarized the information from current publications on Camellia seed saponins, with a focus on the advances made in chemical structures, determination methods, bioactivities and toxicity. We hope this article will stimulate further investigations on these compounds.

Triterpenoid saponins from the genus Camellia: structures, biological activities, and molecular simulation for structure–activity relationship

This review summarizes the isolation, chemical identification, and biochemical activities of Camellia triterpenoid saponins, updating a previous review and encompassing all new studies through September 2017.

Inhibitory Effects of Total Triterpenoid Saponins Isolated from the Seeds of the Tea Plant (Camellia sinensis) on Human Ovarian Cancer Cells

Ovarian cancer is regarded as one of the most severe malignancies for women in the world. Death rates have remained steady over the past five decades, due to the undeniable inefficiency of the current treatment in preventing its recurrence and death. The development of new effective alternative agents for ovarian cancer treatment is becoming increasingly critical. Tea saponins (TS) are triterpenoidsaponins composed of sapogenins, glycosides, and organic acids, which possess a variety of pharmacological activities, and have shown promise in the anti-cancer field. Through cell CellTiter 96^® Aqueous One Solution Cell Proliferation assay (MTS) assay, colony formation, Hoechst 33342 staining assay, caspase-3/7 activities, flow cytometry for apoptosis analysis, and Western blot, we observed that TS isolated from the seeds of tea plants, Camellia sinensis, exhibited strong anti-proliferation inhibitory effects on OVCAR-3 and A2780/CP70 ovarian cancer cell lines. Our results indicate that TS may selectivity inhibit human ovarian cancer cells by mediating apoptosis through the extrinsic pathway, and initiating anti-angiogenesis via decreased VEGF protein levels in a HIF-1α-dependent pathway. Our data suggests that, in the future, TS could be incorporated into a potential therapeutic agent against human ovarian cancer.

Anti-proliferative effect and cell cycle arrest induced by saponins extracted from tea (Camellia sinensis) flower in human ovarian cancer cells

Tea (Camellia sinensis) flower saponins (TFS) have various biological properties. However, the anti-cancer effects of TFS have not been investigated in any detail. Here, we evaluated the anti-cancer effects of TFS using human ovarian cancer cell lines. TFS (1.5 μg/ml) produced significant antiproliferative effects against A2780/CP70 and OVCAR-3 cells by inducing p53-dependent apoptosis and S phase arrest. Further study showed that TFS decreased mitochondrial membrane potential, activated Caspase-3/7, Caspase-8 and Caspase-9 activities, and that the p53 inhibitor PFT-α reversed the TFS-induced cell growth inhibition and apoptosis. In addition, TFS inhibited the expression of Cdc25A, Cdk2, and CyclinD1 and upregulated Cyclin E and Cyclin A, suggesting that the Cdc25A-Cdk2-Cyclin E/A pathway was involved in TFS-induced S phase arrest. Furthermore, the S phase arrest was associated with a Chk2-Cdc25A DNA damage response. These results demonstrated that TFS has promising potential serving as functional food components for prevention of ovarian cancer.

Bioactive benzofuran-chalcanes as potential NQO1 inducers from Millettia pulchra (Benth) kurzvar-laxior (Dunn) Z.Wei

Five chalcanes ((α'R)-2, α'-dimethoxy-furano-[4″, 5'': 3', 4'] chalcane, (α'R, βR)-2', α', β-trimethoxy-furano-[4″, 5'': 3', 4'] chalcane, (α'S, βR)-2', α', β-trimethoxy-furano-[4″, 5'': 3', 4'] chalcane, (α'R, βR)-2', β-dimethoxy-α'-hydroxyethoxy-furano-[4″, 5'': 3', 4'] chalcane, (α'S, βR)-2', β-dimethoxy-α'-hydroxyethoxy-furano-[4″, 5'': 3', 4'] chalcane) and a flavonoid glycoside (3', 7-dihydroxy-6-methoxy-4', 5'-methylenedioxyisoflavone 6-O-β-D- glucopyranoside), together with 15 known components, were isolated from the leaves of Millettia pulchra (Benth) Kurzvar-laxior (Dunn) Z. Wei, a traditional Zhuang medicine. Their chemical structures were established by extensive analysis of NMR, mass spectrometry and ECD spectra. Furthermore compounds (α'R, βR)-2', β-dimethoxy-α'-hydroxyethoxy-furano-[4″, 5'': 3', 4'] chalcane, (α'S, βR)-2', β-dimethoxy-α'-hydroxyethoxy-furano-[4″, 5'': 3', 4'] chalcane, quercetin, methyl 2-O-β-D-glucopyranosylbenzoate, 6,7-dimethoxy-3',4'-methylenedioxyisoflavone and lyoniresinol were suggested to be potential chemopreventive agents because of their significant activity in inducing NQO1 ([NAD(P)H quinine oxidoreductase 1], a phase II metabolism enzyme).