Degradation study of carnosic acid, carnosol, rosmarinic acid, and rosemary extract (Rosmarinus officinalis L.) assessed using HPLC

RP-HPLC characterization of lupenone and β-sitosterol in rhizoma musae and evaluation of the anti-diabetic activity of lupenone in diabetic Sprague-Dawley rats

With the aim of characterizing the active ingredients lupenone and β-sitosterol in Rhizoma Musae samples a reversed-phase HPLC method for the separation of these two compounds in Rhizoma Musae samples was developed (regression coefficient>0.9996). The method was further applied to quantify lupenone and β-sitosterol content in Rhizoma Musae samples cultured in different growth environments. Different variables such as geographical location, growth stage, and harvest time, demonstrated differential effects on lupenone and β-sitosterol levels. Moreover, we determined the optimum conditions for cultivation and harvesting of Rhizoma Musae herbs. Lupenone administration caused a significant reduction in fasting blood glucose (FBG) levels in diabetic rats at doses of 1.78, 5.33, and 16.00 mg·kg⁻¹·day⁻¹ for 14 days, the glycated hemoglobin (HbA1c) levels of diabetic rats also significantly reduced at doses of 5.33, and 16.00 mg·kg⁻¹·day⁻¹, indicating a robust antidiabetic activity. To our knowledge, this is the first report of an optimized HPLC method successfully applied to quantify lupenone and β-sitosterol, and its applicability in optimizing Rhizoma Musae growth. Animal experiments also showed for the first time that lupenone from Rhizoma Musae has anti-diabetic activity.

Improving the sensory and oxidative stability of cooked and chill-stored lamb using dietary rosemary diterpenes

Two dietary rosemary extracts (DREs) containing diterpenes (carnosic acid and carnosol at 1:1 and 2:1 w:w) were tested in fattening lambs to stabilize the sensory quality of cooked and chill-stored patties. A total of 63 lambs were fed freely for 80 ± 5 d with a basal diet supplemented or not with DRE. Minced leg meat from each lamb was used to make patty batches. The patties were cooked at 72 ºC for 2 min, aerobically packed, kept at 2 ºC for up to 4 d and then reheated. Sensory traits (color, odor, flavor, and texture), CIELab color, and lipid oxidation (assessed as TBARS) were determined. In a first experiment, the lamb diet was supplemented with 600 mg of 1:1-DRE or 2:1-DRE kg(-1) feed. The 1:1-DRE diet delayed discoloration, flavor deterioration, and rancidity, while the 2:1-DRE diet was ineffective in this respect. In a second experiment, 4 supplementation levels of 1:1-DRE (0, 200, 400, and 600 mg kg(-1) feed) were compared. Flavor deterioration was delayed when the lamb diet was supplemented with at least 400 mg 1:1-DRE kg(-1) feed. The effects of the diet on the odor, flavor, and color were corroborated by differences in TBARS and CIELab. The results obtained suggest that rosemary diterpenes and/or their active secondary compounds deposited in muscle can act as endogenous antioxidants in cooked lamb. The carnosol intake seems crucial in the antioxidant actions achieved through DRE. The use of rosemary antioxidants in animal feeding would allow meat-based dishes to be preserved longer without adding preservatives.

Carnosic acid inhibits the epithelial-mesenchymal transition in B16F10 melanoma cells: a possible mechanism for the inhibition of cell migration

Carnosic acid is a natural benzenediol abietane diterpene found in rosemary and exhibits anti-inflammatory, antioxidant, and anti-carcinogenic activities. In this study, we evaluated the effects of carnosic acid on the metastatic characteristics of B16F10 melanoma cells. When B16F10 cells were cultured in an in vitro Transwell system, carnosic acid inhibited cell migration in a dose-dependent manner. Carnosic acid suppressed the adhesion of B16F10 cells, as well as the secretion of matrix metalloproteinase (MMP)-9, tissue inhibitor of metalloproteinase (TIMP)-1, urokinase plasminogen activator (uPA), and vascular cell adhesion molecule (VCAM)-1. Interestingly, secretion of TIMP-2 increased significantly in B16F10 cells treated with 10 μmol/L carnosic acid. Additionally, carnosic acid suppressed the mesenchymal markers snail, slug, vimentin, and N-cadherin and induced epithelial marker E-cadherin. Furthermore, carnosic acid suppressed phosphorylation of Src, FAK, and AKT. These results indicate that inhibition of the epithelial-mesenchymal transition may be important for the carnosic acid-induced inhibition of B16F10 cell migration.

Secondary metabolites isolation in natural products chemistry: comparison of two semipreparative chromatographic techniques (high pressure liquid chromatography and high performance thin-layer chromatography)

Chemical investigations on secondary metabolites in natural products chemistry require efficient isolation techniques for characterization purpose as well as for the evaluation of their biological properties. In the case of phytochemical studies, the performance of the techniques is critical (resolution and yield) since the products generally present a narrow range of polarity and physicochemical properties. Several techniques are currently available, but HPLC (preparative and semipreparative) is the most widely used. To compare the performance of semipreparative HPLC and HPTLC for the isolation of secondary metabolites in different types of extracts, we have chosen carvone from spearmint essential oil (Mentha spicata L.), resveratrol from Fallopia multiflora (Thunb.) Haraldson, and rosmarinic acid from rosemary (Rosmarinus officinalis L.) extracts. The comparison was based on the chromatographic separation, the purity and quantity of isolated compounds, the solvent consumption, the duration and the cost of the isolation operations. The results showed that semipreparative HPTLC can in some case offer some advantages over conventional semipreparative HPLC.

Transcriptome analysis of medicinal plant Salvia miltiorrhiza and identification of genes related to tanshinone biosynthesis

Salvia miltiorrhiza Bunge, a perennial plant of Lamiaceae, accumulates abietane-type diterpenoids of tanshinones in root, which have been used as traditional Chinese medicine to treat neuroasthenic insomnia and cardiovascular diseases. However, to date the biosynthetic pathway of tanshinones is only partially elucidated and the mechanism for their root-specific accumulation remains unknown. To identify enzymes and transcriptional regulators involved in the biosynthesis of tanshinones, we conducted transcriptome profiling of S. miltiorrhiza root and leaf tissues using the 454 GS-FLX pyrosequencing platform, which generated 550,546 and 525,292 reads, respectively. RNA sequencing reads were assembled and clustered into 64,139 unigenes (29,883 isotigs and 34,256 singletons). NCBI non-redundant protein databases (NR) and Swiss-Prot database searches anchored 32,096 unigenes (50%) with functional annotations based on sequence similarities. Further assignments with Gene Ontology (GO) terms and KEGG biochemical pathways identified 168 unigenes referring to the terpenoid backbone biosynthesis (including 144 MEP and MVA pathway genes and 24 terpene synthases). Comparative analysis of the transcriptomes identified 2,863 unigenes that were highly expressed in roots, including those encoding enzymes of early steps of tanshinone biosynthetic pathway, such as copalyl diphosphate synthase (SmCPS), kaurene synthase-like (SmKSL) and CYP76AH1. Other differentially expressed unigenes predicted to be related to tanshinone biosynthesis fall into cytochrome P450 monooxygenases, dehydrogenases and reductases, as well as regulatory factors. In addition, 21 P450 genes were selectively confirmed by real-time PCR. Thus we have generated a large unigene dataset which provides a valuable resource for further investigation of the radix development and biosynthesis of tanshinones.

Characterization of in vitro and in vivo metabolites of carnosic acid, a natural antioxidant, by high performance liquid chromatography coupled with tandem mass spectrometry

Carnosic acid (CA) is a widely employed antioxidant and the main active component in rosemary and sage, but its metabolism remains largely unknown. The present study investigated the metabolism of CA in vitro and in vivo for the first time, using high performance liquid chromatography coupled with hybrid triple quadrupole-linear ion trap mass spectrometry (HPLC-Q-trap-MS). A couple of scan modes were adopted in mass spectrometer domain, including Q1 full scan, neutral loss scan-information dependent acquisition-enhanced product ion (NL-IDA-EPI) and precursor ion scan-information dependent acquisition-enhanced product ion (PI-IDA-EPI). In particular, a prediction was carried out on the basis of in vitro metabolism results, and gave birth to a multiple ion monitoring-information dependent acquisition-enhanced product ion (MIM-IDA-EPI) mode aiming to detect the trace metabolites in CA-treated biological samples. A total of ten metabolites (M4-13), along with three degradative products (M1-3), were identified for CA from in vitro metabolism models, including liver microsomes of human and rats (HLMs and RLMs), human intestinal microsomes (HIMs) and two species of Cunninghamella elegans. Twelve (U1-12) and six (F1-6) metabolites were detected from CA-treated urine and feces, respectively. In addition, five metabolites (SM2-6) in vivo were purified and definitely identified using NMR spectroscopy. The results of both in vitro and in vivo metabolism studies indicated poor metabolic stability for CA, and the glucuronidation and oxidation metabolisms extensively occurred for CA in vitro, while oxidation, glucuronidation and methylation were the main metabolic pathways observed in vivo.

Transcriptome analysis of medicinal plant Salvia miltiorrhiza and identification of genes related to tanshinone biosynthesis

Salvia miltiorrhiza Bunge, a perennial plant of Lamiaceae, accumulates abietane-type diterpenoids of tanshinones in root, which have been used as traditional Chinese medicine to treat neuroasthenic insomnia and cardiovascular diseases. However, to date the biosynthetic pathway of tanshinones is only partially elucidated and the mechanism for their root-specific accumulation remains unknown. To identify enzymes and transcriptional regulators involved in the biosynthesis of tanshinones, we conducted transcriptome profiling of S. miltiorrhiza root and leaf tissues using the 454 GS-FLX pyrosequencing platform, which generated 550,546 and 525,292 reads, respectively. RNA sequencing reads were assembled and clustered into 64,139 unigenes (29,883 isotigs and 34,256 singletons). NCBI non-redundant protein databases (NR) and Swiss-Prot database searches anchored 32,096 unigenes (50%) with functional annotations based on sequence similarities. Further assignments with Gene Ontology (GO) terms and KEGG biochemical pathways identified 168 unigenes referring to the terpenoid backbone biosynthesis (including 144 MEP and MVA pathway genes and 24 terpene synthases). Comparative analysis of the transcriptomes identified 2,863 unigenes that were highly expressed in roots, including those encoding enzymes of early steps of tanshinone biosynthetic pathway, such as copalyl diphosphate synthase (SmCPS), kaurene synthase-like (SmKSL) and CYP76AH1. Other differentially expressed unigenes predicted to be related to tanshinone biosynthesis fall into cytochrome P450 monooxygenases, dehydrogenases and reductases, as well as regulatory factors. In addition, 21 P450 genes were selectively confirmed by real-time PCR. Thus we have generated a large unigene dataset which provides a valuable resource for further investigation of the radix development and biosynthesis of tanshinones.