Two New Pentacyclic Triterpene Saponins from the Leaves of Akebia trifoliata.

Two new pentacyclic triterpene saponins, named akebiaoside K (1) and akebiaoside N (2), were isolated from the leaves of Akebia trifoliata, together with five known triterpenoids 3-7. They were all isolated from the leaves of A. trifoliata for the first time. Their structures were established by spectral and chemical means. Triterpenes 5 and 7 were found to show moderate in vitro cytotoxicity against human tumor A549, HeLa and HepG2 cell lines, with IC50 values ranging from 0.023 to 0.038 mM. Triterpenes 5-7 were further revealed to show significant in vitro α-glucosidase inhibitory activity with IC50 values from 0.040 to 0.220 mM, making them more potent than the reference compound acarbose (IC50 0.409 mM). Meanwhile, no obvious inhibitory effects were observed for the isolated triterpene saponins 1-4 in both bioactivity assays.

Chemical composition of volatile oils from the pericarps of Indian sandalwood (Santalum album) by different extraction methods.

The chemical composition of volatile compounds from pericarp oils of Indian sandalwood, Santalum album L., isolated by hydrodistillation and solvent extraction, were analyzed by GC and GC-MS. The pericarps yielded 2.6 and 5.0% volatile oil by hydrodistillation and n-hexane extraction, and they were colorless and yellow in color, respectively. A total of 66 volatile components were detected. The most prominent compounds were palmitic and oleic acids, representing about 40-70% of the total oil. Many fragrant constituents and biologically active components, such as alpha- and beta-santalol, cedrol, esters, aldehydes, phytosterols, and squalene were present in the pericarp oils. This is the first report of the volatile composition of the pericarps of any Santalum species.

[Effects of D-arginine on polyamine content and anaerobic respiration metabolism of cucumber seedling roots under hypoxia stress].

By the method of solution culture, this paper studied the effects of D-arginine on the seedling roots polyamine content and anaerobic respiration metabolism of two cucumber ( Cucumis Sativus L. ) cultivars Zhongnong No. 8 and Lübachun No. 4 differed in hypoxia tolerance. The results showed that under hypoxia stress, the putrescine (Put), spermidine (Spd) and spermine (Spm) contents in the seedling roots of test cultivars increased significantly, and anaerobic respiration accelerated. The ethanol fermentation activity was higher in the seedling roots of hypoxia-tolerant cultivar Lübachun No. 4 than in those of hypoxia-sensitive cultivar Zhongnong No. 8, while lactate fermentation activity had an opposite trend. Comparing with treatment hypoxia, hypoxia plus D -arginine decreased the Put, Spd and Spm contents in roots significantly, enhanced the activities of alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH) and the contents of ethanol and lactate, and inhibited plant growth. Exogenous Put application lessened the effects of D-arginine. Higher level of polyamines in roots could have great benefits for cucumber seedlings to improve their resistance to hypoxia stress.