Integrated metabolome and transcriptome analysis identifies candidate genes involved in triterpenoid saponin biosynthesis in leaves of Centella asiatica (L.) Urban.

Centella asiatica (L.) Urban is a well-known medicinal plant which has multiple pharmacological properties. Notably, the leaves of C. asiatica contain large amounts of triterpenoid saponins. However, there have only been a few studies systematically elucidating the metabolic dynamics and transcriptional differences regarding triterpenoid saponin biosynthesis during the leaf development stages of C. asiatica. Here, we performed a comprehensive analysis of the metabolome and transcriptome to reveal the dynamic patterns of triterpenoid saponin accumulation and identified the key candidate genes associated with their biosynthesis in C. asiatica leaves. In this study, we found that the key precursors in the synthesis of terpenoids, including DMAPP, IPP and ß-amyrin, as well as 22 triterpenes and eight triterpenoid saponins were considered as differentially accumulated metabolites. The concentrations of DMAPP, IPP and ß-amyrin showed significant increases during the entire stage of leaf development. The levels of 12 triterpenes decreased only during the later stages of leaf development, but five triterpenoid saponins rapidly accumulated at the early stages, and later decreased to a constant level. Furthermore, 48 genes involved in the MVA, MEP and 2, 3-oxidosqualene biosynthetic pathways were selected following gene annotation. Then, 17 CYP450s and 26 UGTs, which are respectively responsible for backbone modifications, were used for phylogenetic-tree construction and time-specific expression analysis. From these data, by integrating metabolomics and transcriptomics analyses, we identified CaHDR1 and CaIDI2 as the candidate genes associated with DMAPP and IPP synthesis, respectively, and CaßAS1 as the one regulating ß-amyrin synthesis. Two genes from the CYP716 family were confirmed as CaCYP716A83 and CaCYP716C11. We also selected two UGT73 families as candidate genes, associated with glycosylation of the terpenoid backbone at C-3 in C. asiatica. These findings will pave the way for further research on the molecular mechanisms associated with triterpenoid saponin biosynthesis in C. asiatica.

The Efficacy of Natural Bioactive Compounds for the Treatment of Nasopharyngeal Carcinoma.

The death toll associated with cancer worldwide is constantly on the increase. Efforts to combat and treat the different forms of this disease is also evolving. Nasopharyngeal carcinoma (NPC) is a lethal form of cancer, which is prevalent in Southern China, that is normally treated by using radiotherapy. Here, we will review products obtained from natural sources that have potential cytotoxic and apoptotic properties against NPC. These include grifolin, dihydroartemisinin, luteolin, honokiol, indole-3-carbinol, caffeic acid phenethyl ester, 6-O-angeloylenolin, cucurbitacin E, genistein, helenalin, celastrol, coronarin D, quercetin, trans-cinnamaldehyde, 5'-epimer episilvestrol, silvestrol, arnicolide D, brevilin A, and baicalin hydrate. Ethyl acetate extracts of Wedelia chinensis and aqueous extracts of Ajuga bracteosa are also included although the bioactive compounds involved have yet to be identified. The known mechanism of action of these products is discussed. It is anticipated that one or more of these substances may provide the general population with alternative and cost-effective ways to combat this fatal disease.

Chemical Profiles and Simultaneous Quantification of Aurantii fructus by Use of HPLC-Q-TOF-MS Combined with GC-MS and HPLC Methods.

Aurantii fructus (AF) is a traditional Chinese medicine that has been used to improve gastrointestinal motility disorders for over a thousand years, but there is no exhaustive identification of the basic chemical components and comprehensive quality control of this herb. In this study, high-performance liquid chromatography coupled with quadrupole time of flight mass spectrometry (HPLC-Q-TOF-MS) and gas chromatography coupled mass spectrometry (GC-MS) were employed to identify the basic chemical compounds, and high-performance liquid chromatography (HPLC) was developed to determine the major biochemical markers from AF extract. There were 104 compounds belonging to eight structure types, including 13 amino acids or peptides, seven alkaloids, 18 flavanones, 14 flavones, 15 polymethoxyflavonoids, six triterpenoids, nine coumarins, and 18 volatile oils, as well as four other compounds that were systematically identified as the basic components from AF, and among them, 41 compounds were reported for the first time. Twelve bioactive ingredients were chosen as the benchmark markers to evaluate the quality of AF. The analysis was completed with a gradient elution at a flow rate of 0.7 mL/min within 55 min. This efficient method was validated showing good linearity, precision, stability, repeatability and recovery. Furthermore, the method was successfully applied to the simultaneous determination of 12 chemical markers in different samples of AF. This study could be applied to the identification of multiple bioactive substances and improve the quality control of AF.

Effects of Electroacupuncture on Pain Threshold of Laboring Rats and the Expression of Norepinephrine Transporter and α2 Adrenergic Receptor in the Central Nervous System.

To observe the effects of electroacupuncture on pain threshold of laboring rats and the expression of norepinephrine transporter and α2 adrenergic receptor in the central nervous system to determine the mechanism of the analgesic effect of labor. 120 pregnant rats were divided into 6 groups: a control group, 4 electroacupuncture groups, and a meperidine group. After interventions, the warm water tail-flick test was used to observe pain threshold. NE levels in serum, NET, and α2AR mRNA and protein expression levels in the central nervous system were measured. No difference in pain threshold was observed between the 6 groups before intervention. After intervention, increased pain thresholds were observed in all groups except the control group with a higher threshold seen in the electroacupuncture groups. Serum NE levels decreased in the electroacupuncture and MP groups. Increases in NET and α2AR expression in the cerebral cortex and decreases in enlarged segments of the spinal cord were seen. Acupuncture increases uptake of NE via cerebral NET and decreases its uptake by spinal NET. The levels of α2AR are also increased and decreased, respectively, in both tissues. This results in a decrease in systemic NE levels and may be the mechanism for its analgesic effects.

Garlic supplementation increases peripheral blood flow: a role for interleukin-6?

There is considerable epidemiological and clinical evidence that regular garlic supplementation reduces cardiovascular risk. In this study, we have investigated the hypothesis that dietary garlic supplementation increases tissue blood flow and this is mediated by the vasodilatory actions of interleukin-6 (IL-6). Venous occlusion plethysmography was used to measure resting calf blood flow before and after oral administration of 600 mg of garlic tablets once daily for 7 days in 13 young healthy female volunteers (treatment group) and 13 female controls matched for age and body mass index (BMI). Blood samples were obtained at the time of plethysmography to measure plasma levels of IL-6, nitrate, nitrite and c-GMP. In the treatment group, calf blood flow increased significantly from 3.01 (2.56 to 3.3) ml min(-1) 100 mL(-1) of tissue before garlic to 3.46 (3.0 to 4.03) ml min(-1) 100 mL(-1) of tissue after 7 days of garlic (P = 0.001). Plasma IL-6 concentrations increased significantly from 54.6 (32.3 to 151.6) mcg/mL before to 151 (135.75 to 422.3) mcg/mL after 7 days of garlic (P = 0.02). However, there was no significant change in the plasma levels of nitrate, nitrite and c-GMP after the garlic (P = 0.4, 0.9 and 0.65 respectively). In the control group, resting calf blood flow and plasma levels of IL-6, nitrite, nitrate and c-GMP remained unchanged after 7 days (P = 0.62, 0.92, 0.28 and 0.35 respectively). Calf blood flow showed a non-linear correlation with plasma IL-6 levels after garlic supplementation (r = 0.86, p = <0.001) but not before. There was no significant relationship between blood flow and plasma nitrate, nitrite and c-GMP in either groups and between blood flow and IL-6 in the control group. These data suggest that garlic supplementation increases resting tissue blood flow and this may be mediated by IL-6.