Secondary Metabolites from the Fruit Shells of Camellia oleifera

Applications of Chinese Camellia oleifera and its By-Products: A Review

Camellia oleifera is a woody oil tree species unique to China that has been cultivated and used in China for more than 2,300 years. Most biological research on C. oleifera in recent years has focused on the development of new varieties and breeding. Novel genomic information has been generated for C. oleifera, including a high-quality reference genome at the chromosome level. Camellia seeds are used to process high-quality edible oil; they are also often used in medicine, health foods, and daily chemical products and have shown promise for the treatment and prevention of diseases. C. oleifera by-products, such as camellia seed cake, saponin, and fruit shell are widely used in the daily chemical, dyeing, papermaking, chemical fibre, textile, and pesticide industries. C. oleifera shell can also be used to prepare activated carbon electrodes, which have high electrochemical performance when used as the negative electrode of lithium-ion batteries. C. oleifera is an economically valuable plant with diverse uses, and accelerating the utilization of its by-products will greatly enhance its industrial value.

Phytochemical constituents of Camellia osmantha fruit cores with antithrombotic activity

Camellia osmantha is a new species of the genus Camellia and is an economically important ornamental plant. Its activity and ingredients are less studied than other Camellia plants. This study investigated the antithrombotic effect and chemical components of C. osmantha fruit cores using platelet aggregation assays and coagulation function tests. The cores of C. osmantha fruits were extracted with ethanol to obtain a crude extract. The extract was dissolved in water and further eluted with different concentrations of methanol on an MCI resin column to obtain three fractions. These samples were used for antithrombotic activity tests and phytochemical analysis. The results showed that the extract and its fractions of C. osmantha have strong antithrombotic activity, significantly reducing the platelet aggregation rate and prolonging the thrombin time (TT). The total saponins, flavonoids, and polyphenols in the active fractions may be responsible for the antithrombotic activity. The chemical constituents were analyzed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS). Twenty-three compounds were identified rapidly and accurately. Among them, ellagic acid, naringenin, and quercetin 3-O-glucuronide may be important antithrombotic constituents. Furthermore, interactions between these compounds and the P2Y1 receptor were investigated via molecular modeling, because the P2Y1 receptor is a key drug target of antiplatelet aggregative activity. The molecular docking results suggested that these compounds could combine tightly with the P2Y1R protein. Our results showed that C. osmantha fruit cores are rich in polyphenols, flavonoids, and saponins, which can be developed into a promising antithrombotic functional beverage for the prevention and treatment of cardiovascular and cerebrovascular diseases.

Anatomy and lignin deposition of stone cell in Camellia oleifera shell during the young stage

As the by-products of edible oil production with rich lignin, the reserves of Camellia oleifera shell were abundant and had a great economic value. Lignin was the most important limiting factor during the conversion of plant biomass to pulp or biofuels, which mainly deposited in the stone cells of C. oleifera shells. Thus, its lignin deposition made the function of stone cells in the ripening process of the shell clearer, and provided a theoretical basis for the potential utilization of the biomass of C. oleifera shells. In this study, the paraffin embedding method was used to investigate the development and difference of stone cell in the fruitlet. The lignin deposition characteristics of stone cell were analyzed by the fluorescence microscopy and Wiesner and Mäule method. The chemical-functional group types of lignin in the stone cell of C. oleifera shell were examined by the ultraviolet spectrophotometer and transform infrared spectroscopy. The stone cells, vessels, parenchyma, and vascular tissue had existed during the young fruit growing period. The anatomical characteristics and the cell tissue ratio inverse relationship between stone cell and parenchymal cell suggested that stone cells developed from parenchymal cells. With the growth of shell, the stone cell wall thickened, and thickness-to-cavity ratio from 0 to 3.6. The fluorescent results showed that lignin content increased continuously; during shell development, the mean brightness of stone cell wall from 0 to 77.9 sections was stained with phloroglucinol-HCl, and Mäule revealed the presence of G-S-lignin in stone cells, and ImageJ results showed that G-lignin was distributed in the entire stone cell wall, while S-lignin deposition accounted for 48.59% of the cell wall area. In the FTIR spectra, the shell was identified as containing G-S-lignin.

Mesopore structure in Camellia Oleifera shell

Generally, Camellia oleifera shells are byproducts of edible oil production and are often incinerated or discarded as agricultural waste without any sustainable uses. Although numerous studies have focused on the C. oleifera shell, few studies have examined its biological characteristics, particularly its internal mesoporosity. The aim of the present study was to elucidate the microscopic biological structure of C. oleifera shells to explore their potential applications. Paraffin-embedded slices of C. oleifera shells were observed on different planes using an optical microscope. Supercritically dried samples were prepared and assessed using the nitrogen adsorption-desorption technique to reveal mesopore structural features. The present article shows that C. oleifera shells were mainly made up of stone cells, parenchyma tissue, spiral vessels, and vascular bundles. The key features of the cells were the pits in the cell walls of stone cells and vessels, which are associated with the abundant mesopores in C. oleifera shells. C. oleifera shells have an advantage over woody materials based on their mesoporosity features. C. oleifera shells are ideal raw materials that could serve as biomass templates or find applications as other high-performance biomimetic materials.