Compounds with NO Inhibitory Effect from the Rattan Stems of Sinomenium acutum, a Kind of Chinese Folk Medicine for Treating Rheumatoid Arthritis.

Three new alkaloids (1-3), one new diphenyl ether (4) and fifteen known alkaloids (5-19) were isolated from the rattan stems of Sinomenium acutum. Comprehensive analyses of HR-ESI-MS, 1D (1 H and 13 C), 2D-NMR (1 H-1 H COSY, HSQC, HMBC, NOESY), circular dichroism (CD), UV and IR revealed the structures and absolute configurations of these new compounds. The structures of other compounds were determined by comparison of their 1 H and 13 C-NMR data with previous literature reports. By measuring the amount of NO produced, the anti-inflammatory properties of the isolated compounds were studied. The results showed that compounds 4 and 5 had strong NO inhibitory activity.

Full-length transcriptome and metabolite analysis reveal reticuline epimerase-independent pathways for benzylisoquinoline alkaloids biosynthesis in Sinomenium acutum.

Benzylisoquinoline alkaloids (BIAs) are a large family of plant natural products with important pharmaceutical applications. Sinomenium acutum is a medicinal plant from the Menispermaceae family and has been used to treat rheumatoid arthritis for hundreds of years. Sinomenium acutum contains more than 50 BIAs, and sinomenine is a representative BIA from this plant. Sinomenine was found to have preventive and curative effects on opioid dependence. Despite the broad applications of S. acutum, investigation on the biosynthetic pathways of BIAs from S. acutum is limited. In this study, we comprehensively analyzed the transcriptome data and BIAs in the root, stem, leaf, and seed of S. acutum. Metabolic analysis showed a noticeable difference in BIA contents in different tissues. Based on the study of the full-length transcriptome, differentially expressed genes, and weighted gene co-expression network, we proposed the biosynthetic pathways for a few BIAs from S. acutum, such as sinomenine, magnoflorine, and tetrahydropalmatine, and screened candidate genes involved in these biosynthesis processes. Notably, the reticuline epimerase (REPI/STORR), which converts (S)-reticuline to (R)-reticuline and plays an essential role in morphine and codeine biosynthesis, was not found in the transcriptome data of S. acutum. Our results shed light on the biogenesis of the BIAs in S. acutum and may pave the way for the future development of this important medicinal plant.

Ten New Dammarane-Type Saponins with Hypolipidemia Activity from a Functional Herbal Tea-Gynostemma pentaphyllum.

Gynostemma pentaphyllum (thumb.) Makino is a functional herbal tea commonly used in Asian countries and regions to reduce blood lipid levels. G. pentaphyllum saponin is the main component, but there are still a large number of components with lipid-lowering activity that have not been found. In this study, 10 novel dammarane-type saponins, (1-10) and a known one (11) were isolated from G. pentaphyllum. Ten new compounds were identified and named as yunnangypenosides A-J (1-10), and another known one (11) was also obtained. Their chemical structures were determined by MS, NMR spectroscopic analyses. Moreover, the cytotoxicities on human HepG-2 hepatocellular carcinoma cells of these isolates were evaluated, and the results showed that compounds 1-11 had no obvious cytotoxicity. Finally, all these compounds were evaluated for their lipid-lowering effect by means of the oil red O staining method. Ten compounds could significantly reduce lipid levels except of 2, especially 8 exhibite the strongest hypolipidemia activity.