Oleiferasaponin A2, a Novel Saponin from Camellia oleifera Abel. Seeds, Inhibits Lipid Accumulation of HepG2 Cells Through Regulating Fatty Acid Metabolism.

A new triterpenoid saponin, named oleiferasaponin A2, was isolated and identified from Camellia oleifera defatted seeds. Oleiferasaponin A2 exhibited anti-hyperlipidemic activity on HepG2 cell lines. Further study of the hypolipidemic mechanism showed that oleiferasaponin A2 inhibited fatty acid synthesis by significantly down-regulating the expression of SREBP-1c, FAS and FAS protein, while dramatically promoting fatty acid ß-oxidation by up-regulating the expression of ACOX-1, CPT-1 and ACOX-1 protein. Our results demonstrate that the oleiferasaponin A2 possesses potential medicinal value for hyperlipidemia treatment.

Cytotoxic and Hypoglycemic Activity of Triterpenoid Saponins from Camellia oleifera Abel. Seed Pomace.

One new and three known triterpenoid saponins were isolated and identified from Camellia oleifera seeds through IR, NMR, HR-ESI-MS and GC-MS spectroscopic methods, namely oleiferasaponin A3, oleiferasaponin A1, camelliasaponin B1, and camelliasaponin B2. The structure of oleiferasaponin A3 was elucidated as 16α-hydroxy-21ß-O-angeloyl-22α-O-cinnamoyl-23α-aldehyde-28-dihydroxymethylene-olean-12-ene-3ß-O-[ß-d-galactopyranosyl-(1→2)]-[ß-d-xylopyranosyl-(1→2)-ß-d-galactopyranosyl-(1→3)]-ß-d-gluco-pyranosiduronic acid. Camelliasaponin B1 and camelliasaponin B2 exhibited potent cytotoxic activity on three human tumour cell lines (human lung tumour cells (A549), human liver tumour cells (HepG2), cervical tumour cells (Hela)). The hypoglycemic activity of oleiferasaponin A1 was testified by protecting pancreatic ß-cell lines from high-glucose damage.

Qualitative and quantitative analysis of triterpene saponins from tea seed pomace (Camellia oleifera Abel) and their activities against bacteria and fungi.

A method using LC-ESI-IT-TOF/MS and LC/UV-ELSD was established to qualitatively analyze triterpene saponins obtained from the tea seed pomace (Camellia oleifera Abel). In addition, the quantitative analysis of oleiferasaponin A1 using LC/UV was developed. The purified total saponins did not exhibit any inhibitory effects at concentrations ranging from 0.1 to 10 mg/mL against the tested bacteria, except for Staphyloccocus aureus and Escherichia coli. By contrast, higher inhibitory activity was seen against the tested fungi, especially against Bipolaris maydis. Following treatment with an MIC value of 250 µg/mL for 24 h, the mycelial morphology was markedly shriveled in appearance or showed flattened and empty hyphae, with fractured cell walls, ruptured plasmalemma and cytoplasmic coagulation or leakage. These structural changes hindered the growth of mycelia.

Lipoxygenase gene expression in ripening kiwifruit in relation to ethylene and aroma production.

During postharvest ripening of kiwifruit [ Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson var. deliciosa cv. Bruno] at 20 degrees C, six lipoxygenase (LOX) genes exhibited different expression patterns. AdLox1 and AdLox5 were up-regulated during ripening, and transcript accumulation was delayed by 1-methylcyclopropene (1-MCP), whereas AdLox2, AdLox3, AdLox4, and AdLox6 were down-regulated with ripening. Levels of two volatiles arising from the LOX pathway, that is, n-hexanal and (E)-2-hexenal, were highest after harvest and declined during ripening at 20 degrees C, whereas the characteristic kiwifruit esters ethyl and methyl butanoate levels increased late in the ripening process. Individual fatty acid concentrations underwent little change during ripening, with linoleic (LA) and linolenic (LeA) acids constituting about 40% of the total. Application of LA and LeA to kiwifruit flesh disks promoted LOX activity and n-hexanal and (E)-2-hexenal generation, whereas inhibitors of LOX, n-propyl gallate (n-PG) and nordihydroguariaretic acid (NDGA), caused a parallel reduction in enzyme activity and in the production of C6 aldehydes. The six LOX genes showed different sensitivities to the LOX substrates and inhibitors. The ethylene up-regulated genes AdLox1 and AdLox5 were induced by LA and LeA and inhibited by n-PG and NDGA. Of the LOX genes that were down-regulated by ethylene, only AdLox4 and AdLox6 were stimulated in response to the substrates and retarded by the inhibitors. The possible roles of the six LOX genes in kiwifruit ripening and aroma development are discussed.

[Changes in respiratory rate, ethylene production rate and quality of postharvest Chinese bayberry fruits with different maturities].

Harvested fruits of three Chinese bayberry (Myrica rubra Sieb. & Zucc.) varieties, i.e. "Biqi", "Dongkui" and "Zaodamei" which were divided into three maturities (designated as "Immature", "Mature" and "Ripe") according to fruit colour, were investigated for the changes in climacteric pattern and quality at 20 degrees C. Respiration rate and ethylene production rate were underwent 3 h during 48 h storage. Our result showed that both Immature and Mature fruits underwent rises in respiration and ethylene production rate of a climacteric rise, but no such peak was observed in Ripe fruit (Fig.1 and 2). Total soluble solids (TSS) contents increased with maturity and decreased over the 48 h at 20 degrees C (Fig.3); titratable acidity (TA) decreased with the maturity and throughout 48 h storage period (Fig.4). In "Biqi" Chinese bayberry fruit, PAL activities increased in Immature and Mature fruit, but, it decreased in Ripe fruit during the storage period; the change in Cy-3-Glu with fruit ripening was consistent with PAL activities (Table 1); there was significant positive correlation between CIRG (Color Index for Red Grape) values and Cy-3-Glu content (r=0.96**). This study provides important information on the postharvest behaviour of Chinese bayberry fruit, and our result shows that it is climacteric fruit.