Supercritical Carbon Dioxide Extraction, Fatty Acid Composition, Oxidative Stability, and Antioxidant Effect of Torreya grandis Seed Oil

Diterpenoids from the bark of Torreya grandis and their cytotoxicity activity

Four previously undescribed diterpenoids (2-5) were isolated from the bark of Torreya grandis, along with ten known analogues. The structures of the compounds were elucidated using NMR, HR-ESIMS, and ECD calculation. The cytotoxic effects of the isolated compounds on HCT-116, AsPC-1, and HepG2 cells were evaluated using the MTT assay. Compound 6 exhibited significant cytotoxicity against HepG2 cells. Further experiments revealed that compound 6 could arrest the G2 phase process in HepG2 cells through the JAK2/STAT3 signaling pathway.

Role of TgVIN1 and TgPEPCK in sugar/starch and lipid metabolism pathways in Torreya grandis seeds under foliar fertilizer treatments

Foliar fertilizers quickly replenish nutrients for plant growth, boosting production and quality. However, how this affects metabolite accumulation in fruits is unclear. In this study, the metabolome and transcriptome of Torreya grandis seeds were investigated after five different foliar fertilizer treatments. Based on the results, foliar fertilizer treatments significantly altered the visual properties and nutritional quality of T. grandis seeds. According to the transcriptome and metabolome data, the differential metabolites and genes in T. grandis seeds were enriched in the sugar/starch and lipid metabolism-related pathways. Correlation analysis revealed that TgVIN1 and TgPEPCK play key roles in sugar/starch and lipid metabolism pathways, respectively. A dual-luciferase analysis and yeast one-hybrid assay were used to examine the regulation of candidate transcription factors on TgVIN1 and TgPEPCK expression. The results showed that TgHDZIP1 and TgMYB7 could directly bind to the TgVIN1 promoter and activate TgVIN1 expression. Similarly, TgIWS1 could directly bind to the TgPEPCK promoter. Transient overexpression of TgVIN1 increased the contents of fructose, soluble sugar and starch in and TgPEPCK significantly increased the C16:1 content in tobacco leaves, respectively. Our results contribute to the mechanisms underlying sucrose/starch and lipid metabolism as affected by foliar fertilizer treatments.

Functional compounds of Torreya grandis nuts and their processing byproducts: Extraction process, health benefits, and food applications - A comprehensive review

Torreya grandis (TG) nuts are highly valued for their rich content of bioactive compounds including lipids, proteins, carbohydrates, phenolic compounds, vitamins, and minerals, credited with numerous health benefits. In addition to their use in various culinary applications, such as baked goods and snacks, TG nuts are valuable source of high-quality oil rich in ω-3 and ω-6 unsaturated fatty acids, which has been shown to have anti-obesity, neuroprotective, and anti-diabetes effects. Besides, the byproducts from TG nuts processing, like the fruit aril and oil cake, are valuable sources of essential oils and proteins, respectively, with notable antioxidant, antimicrobial, and antifungal properties. Despite their nutrient profile and health promoting effects, TG nuts and their processing byproducts have received limited attention, hindering their wider use in food and medicinal applications. This review aims to bring attention to TG nuts by highlighting their nutritional and health benefits, and exploring their potential novel applications in the food sector. Research gaps were outlined to guide future research and products development. TG nuts hold great potential as functional foods and their byproducts like the aril could be repurposed for essential oil extraction, suitable for application in food flavoring and antimicrobial packaging. However, broader application of TG nuts and their byproducts in the food industry remain limited, and research regarding their nutrients profile is not comprehensive. Additionally, the bioactive compounds linked to their health benefits have not been properly identified, highlighting the need for further studies to explore their full potential.

Transcriptome-referenced association study provides insights into the regulation of oil and fatty acid biosynthesis in Torreya grandis kernel

INTRODUCTION

Torreya grandis is a gymnosperm belonging to Taxodiaceae. As an economically important tree, its kernels are edible and rich in oil with high unsaturated fatty acids, such as sciadonic acid. However, the kernels from different T. grandis landraces exhibit fatty acid and oil content variations.

OBJECTIVES

As a gymnosperm, does T. grandis have special regulation mechanisms for oil biosynthesis? The aim of this study was to dissect the genetic architecture of fatty acid and oil content and the underlying mechanism in T. grandis.

METHODS

We constructed a high integrity reference sequence of expressed regions of the genome in T. grandis and performed transcriptome-referenced association study (TRAS) for 10 fatty acid and oil traits of kernels in the 170 diverse T. grandis landraces. To confirm the TRAS result, we performed functional validation and molecular biology experiments for oil significantly associated genes.

RESULTS

We identified 41 SNPs from 34 transcripts significantly associated with 7 traits by TRAS (-log10 (P) greater than 6.0). Results showed that LOB domain-containing protein 40 (LBD40) and surfeit locus protein 1 (SURF1) may be indirectly involved in the regulation of oil and sciadonic acid biosynthesis, respectively. Moreover, overexpression of TgLBD40 significantly increased seed oil content. The nonsynonymous variant in the TgLBD40 coding region discovered by TRAS could alter the oil content in plants. Pearson's correlation analysis and dual-luciferase assay indicated that TgLBD40 positively enhanced oil accumulation by affecting oil biosynthesis pathway genes, such as TgDGAT1.

CONCLUSION

Our study provides new insights into the genetic basis of oil biosynthesis in T. grandis and demonstrates that integrating RNA sequencing and TRAS is a powerful strategy to perform association study independent of a reference genome for dissecting important traits in T. grandis.

Diterpenoids from Torreya grandis and their cytotoxic activities

Eight previously undescribed diterpenoids, along with eleven previously reported analogues, were obtained from the supercritical CO2 extracts of Torreya grandis aril. The structures of these compounds were elucidated based on HRESIMS, NMR, ECD, and single-crystal X-ray diffraction data. In the MTT assay, compound 18 exhibited significant inhibitory effects on two human colon cancer cell lines, HT-29 and HCT 116 cells, with IC50 values of 7.37 μM and 6.55 μM, respectively. It was found that compound 18 induced apoptosis and significantly inhibited the migration of HCT 116 colon cancer cells in a concentration-dependent manner.

Genomics analysis of three phosphorus-dissolving bacteria isolated from Torreya grandis soil

With the increasingly serious problem of phosphorus deficiency in the subtropical zone, chemical fertilizers are widely used. But it pollutes the environment. Phosphorus-solubilizing microorganisms (PSMs) are referred to as a new solution to this problem. We explored the phosphorus-dissolving characteristics of PSB strains isolated from the rhizosphere soil of Torreya grandis to provide a theoretical basis for selecting the strain for managing phosphorus deficiency in subtropical soils and also provides a more sufficient theoretical basis for the utilization of PSMs. From 84 strains, three strains exhibiting high phosphorus solubility and strong IAA producing capacity were selected through a series of experiments. The phosphate-solubilizing capacity of the three selected strains W1, W74, and W83 were 339.78 mg/L, 332.57 mg/L, and 358.61 mg/L, respectively. Furthermore, W1 showed the strongest IAA secreting capacity of 8.62 mg/L, followed by W74 (7.58 mg/L), and W83 (7.59 mg/L). Determination by metabolites, it was observed that these three strains dissolved phosphorus by secreting a large amount of lactic acid, aromatic acid, and succinic acid. The genome of these PSBs were sequenced and annotated in this study. Our results revealed that PSB primarily promotes their metabolic pathway, especially carbon metabolism, to secrete plenty organic acids for dissolving insoluble phosphorus.

Purification, Identification, and Inhibitory Mechanisms of a Novel ACE Inhibitory Peptide from Torreya grandis

Torreya grandis meal has a high protein content and an appropriate amino acid ratio, making it an excellent protein source for producing ACE inhibitory peptides. To promote its application in food, medicine, and other fields, an alkaline protease hydrolysate of Torreya grandis was used in this study to isolate and identify a novel angiotensin-converting enzyme inhibitory peptide, VNDYLNW (VW-7), using ultrafiltration, gel chromatography purification, LC-MS/MS, and in silico prediction. The results show that the IC50 value of VW-7 was 205.98 µM. The Lineweaver-Burk plot showed that VW-7 had a mixed-type inhibitory effect on ACE. Meanwhile, according to the results of molecular docking, VW-7 demonstrated a strong affinity for ACE (binding energy -10 kcal/mol). VW-7 was bound to ACE through multiple binding sites. In addition, VW-7 could remain active during gastrointestinal digestion in vitro. Nitric oxide (NO) generation in human endothelial cells could rise after receiving a pretreatment with VW-7. These results indicated that Torreya grandis meal protein can be developed into products with antihypertensive function, and VW-7 has broad application prospects in the field of antihypertensive.

Sciadonic acid attenuates high-fat diet-induced obesity in mice with alterations in the gut microbiota

Obesity has been reported to be associated with dysbiosis of gut microbiota. Sciadonic acid (SC) is one of the main functional components of Torreya grandis "Merrillii" seed oil. However, the effect of SC on high-fat diet (HFD)-induced obesity has not been elucidated. In this study, we evaluated the effects of SC on lipid metabolism and the gut flora in mice fed with a high-fat diet. The results revealed that SC activates the PPARα/SREBP-1C/FAS signaling pathway and reduces the levels of total cholesterol (TC), triacylglycerols (TG), and low-density lipoprotein cholesterol (LDL-C), but increases the level of high-density lipoprotein cholesterol (HDL-C) and inhibits weight gain. Among them, high-dose SC was the most effective; the TC, TG and LDL-C levels were reduced by 20.03%, 28.40% and 22.07%, respectively; the HDL-C level was increased by 8.55%. In addition, SC significantly increased glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) levels by 98.21% and 35.17%, respectively, decreased oxidative stress, and ameliorated the pathological damage to the liver caused by a high-fat diet. Furthermore, SC treatment altered the composition of the intestinal flora, promoting the relative abundance of beneficial bacteria such as Lactobacillus and Bifidobacterium, while simultaneously decreasing the relative abundance of potentially harmful bacteria such as Faecalibaculum, norank_f_Desulfovibrionaceae, and Romboutsia. Spearman's correlation analysis indicated that the gut microbiota was associated with SCFAs and biochemical indicators. In summary, our results suggested that SC can improve lipid metabolism disorders and regulate the gut microbial structure.

Fractionated Antioxidant and Anti-inflammatory Kernel Oil from Torreya fargesii

Polymethylene-interrupted polyunsaturated fatty acids (PMI-PUFAs) are emerging functional lipids with proven antioxidant and anti-inflammatory effects. In this study, a typical PMI-PUFA, sciadonic acid (C20:3, 5c 11c 14c), was enriched in the kernel oil of Torreya fargesii (T. fargesii) by fractionation. Fractionated kernel oil of T. fargesii (containing 25% sciadonic acid) showed equal stability and similar radical scavenging ability compared with the non-fractionated oil. In anti-inflammatory tests, fractionated kernel oil was shown to inhibit the activity of phosphodiesterase (PDE-5, efficiency 80% at 133.7 μg/mL) and lipoxygenase-5 (LOX-5, efficiency 65% at 66.7 μg/mL) more effectively than the non-fractionated oil. This shows that increasing the amount of sciadonic acid can enhance the anti-inflammatory effect of the kernel oil. This research also indicates that fractionation is a feasible way to obtain sciadonic acid-rich functional oil with potential pharmacological effects.

Full-Length Transcriptome Analysis of the Genes Involved in Tocopherol Biosynthesis in Torreya grandis

The seeds of Torreya grandis (Cephalotaxaceae) are rich in tocopherols, which are essential components of the human diet as a result of their function in scavenging reactive oxygen and free radicals. Different T. grandis cultivars (10 cultivars selected in this study were researched, and their information is shown in Table S1 of the Supporting Information) vary enormously in their tocopherol contents (0.28-11.98 mg/100 g). However, little is known about the molecular basis and regulatory mechanisms of tocopherol biosynthesis in T. grandis kernels. Here, we applied single-molecule real-time (SMRT) sequencing to T. grandis (X08 cultivar) for the first time and obtained a total of 97 211 full-length transcripts. We proposed the biosynthetic pathway of tocopherol and identified eight full-length transcripts encoding enzymes potentially involved in tocopherol biosynthesis in T. grandis. The results of the correlation analysis between the tocopherol content and gene expression level in the 10 selected cultivars and different kernel developmental stages of the X08 cultivar suggested that homogentisate phytyltransferase coding gene ( TgVTE2b) and γ-tocopherol methyltransferase coding gene ( TgVTE4) may be key players in tocopherol accumulation in the kernels of T. grandis. Subcellular localization assays showed that both TgVTE2b and TgVTE4 were localized to the chloroplast. We also identified candidate regulatory genes similar to WRI1 and DGAT1 in Arabidopsis that may be involved in the regulation of tocopherol biosynthesis. Our findings provide valuable genetic information for T. grandis using full-length transcriptomic analysis, elucidating the candidate genes and key regulatory genes involved in tocopherol biosynthesis. This information will be critical for further molecular-assisted screening and breeding of T. grandis genotypes with high tocopherol contents.

Antioxidant and Tyrosinase Inhibitory Activities of Seed Oils from Torreya grandis Fort. ex Lindl

Torreya grandis Fort. ex Lindl. is a plant belonging to the Taxaceae family and Torreya grandis cv. Merrillii is the only grafted and thoroughbred species belonging to this species. In this study, we extracted five different seed oils, including T. grandis seed oil (TGSO), T. grandis "Xiangyafei" seed oil (XYSO), T. grandis "Zhimafei" seed oil (ZMSO), T. grandis "Majus"seed oil (TGMSO), and T. grandis "cunguangfei" seed oil (CGSO) using physical pressure. The resulting extracts were analyzed to determine their fatty acid composition, antioxidant activity, and inhibitory activity towards tyrosinase. The results of the antioxidant activity assays revealed that XYSO and ZMSO exhibited much greater DPPH radical scavenging activity and ferric reducing power than TGSO. Notably, all five of the seed oils showed dose-dependent inhibitory activity towards tyrosinase. XYSO and TGSO gave the highest activities of all of the seed oils tested in the current study against monophenolase and diphenolase, with IC50 values of 227.0 and 817.5μg/mL, respectively. The results of this study show that wild TGSOs exhibit strong antioxidant and tyrosinase inhibition activities. These results therefore suggest that wild TGSOs could be used as a potential source of natural antioxidant agents and tyrosinase inhibitors.

Chemical components of cold pressed kernel oils from different Torreya grandis cultivars

The chemical compositions of cold pressed kernel oils of seven Torreya grandis cultivars from China were analyzed in this study. The contents of the chemical components of T. grandis kernels and kernel oils varied to different extents with the cultivar. The T. grandis kernels contained relatively high oil and protein content (45.80-53.16% and 10.34-14.29%, respectively). The kernel oils were rich in unsaturated fatty acids including linoleic (39.39-47.77%), oleic (30.47-37.54%) and eicosatrienoic acid (6.78-8.37%). The kernel oils contained some abundant bioactive substances such as tocopherols (0.64-1.77mg/g) consisting of α-, β-, γ- and δ-isomers; sterols including β-sitosterol (0.90-1.29mg/g), campesterol (0.06-0.32mg/g) and stigmasterol (0.04-0.18mg/g) in addition to polyphenols (9.22-22.16μgGAE/g). The results revealed that the T. grandis kernel oils possessed the potentially important nutrition and health benefits and could be used as oils in the human diet or functional ingredients in the food industry.

Advanced development in phytochemicals analysis of medicine and food dual purposes plants used in China (2011-2014)

In 2011, we wrote a review for summarizing the phytochemical analysis (2006-2010) of medicine and food dual purposes plants used in China (Zhao et al., J. Chromatogr. A 1218 (2011) 7453-7475). Since then, more than 750 articles related to their phytochemical analysis have been published. Therefore, an updated review for the advanced development (2011-2014) in this topic is necessary for well understanding the quality control and health beneficial phytochemicals in these materials, as well as their research trends.