Chemical constituents from the aerial parts of Juncus setchuensis

Juncus setchuensis is a perennial herbaceous plant found in marshes, swamps, and other poorly drained sites. Despite being so abundant in the southwest of China, only one literature reference has reported about its chemical components. The present phytochemical investigation on this plant led to isolations of 13 compounds (including four 9,10-dihydrophenanthrenes, one phenanthrene, one flavonone, two mono-aromatics, one steroid, one anthraquinone and three diterpenoid tanshinones), five of them were isolated form this plant for the first time, four of them, one anthraquinone and three diterpenoid tanshinones, were reported for the first time in this genus. The presence of phenanthrenes, 9,10-dihydrophenanthrenes in the Juncus genus could be of taxonomic importance.     

Danshen diversity defeating dementia

Salvia miltiorrhiza (danshen) is widely used for the clinical treatment of cerebral ischemia and cardiovascular diseases. Its diverse molecular makeup of simple and poly hydroxycinnamic acids and diterpenoid quinones are also associated with its beneficial health effects such as improved cognitive deficits in mice, protection of neuronal cells, prevention of amyloid fibril formation and preformed amyloid fibril disaggregation related to Alzheimer’s disease. Whilst the in vitro studies have therapeutic promise, the anti-dementia effect/impact of danshen however depends on its absorbed constituents and pharmacokinetic properties. Both the water and lipid danshen fractions have been shown to have low oral bioavailability and at physiological pH, the polyphenolic carboxylate anions are not brain permeable. To tap into the many neuroprotective and other biological benefits of danshen, the key challenge resides in developing danshen nanopharmaceuticals, semi-synthetic pro-drug forms of its constituents to improve its biocompatability, that is, absorption, circulation in bloodstream and optimization of BBB permeability.     

Cultivar Variations of Australian‐Grown Danshen (Salvia miltiorrhiza): Bioactive Markers and Root Yields

Danshen (Salvia miltiorrhiza Bunge, Lamiaceae) is a commonly used and highly valued Chinese medicinal herb grown widely in China. In the present work, we studied cultivar variations of Australian‐grown Danshen in order to select optimal cultivars for local herbal production. Root yields of seven cultivars, V1–V7, were monitored in a one‐year field trial, and bioactive markers, including cryptotanshinone, tanshinone I, tanshinone IIA, and salvianolic acid B, were quantitatively determined using a validated RP‐HPLC method. Significant variations were found in root yields, root production efficiencies, and contents of the bioactive marker compounds. Linear correlations were observed among the contents of three tanshinones but not among those of tanshinones and salvianolic acid B. Among the cultivars, V6 was the best cultivar for production of tanshinones, and V4 and V5 were best for production of salvianolic acid B. The findings indicate that it is possible to achieve optimal root yields, and high contents of tanshinones and salvianolic acid B by selecting specific Danshen cultivars.     

Plant density-dependent variations in bioactive markers and root yield in Australian-grown Salvia miltiorrhiza Bunge

The plant density‐dependent variations in the root yield and content, and the yield of biomarkers in Australian grown Salvia miltiorrhiza Bunge , a commonly used Chinese medicinal herb for the treatment of cardiovascular diseases, were investigated in a field trial involving six different plant densities. The key biomarker compounds cryptotanshinone, tanshinone I, tanshinone IIA, and salvianolic acid B were quantified by a validated RP‐HPLC method, and the root yields were determined per plant pair or unit area. There were significant variations (p<0.05) in the root yields and contents and the yields of the biomarkers between the different plant densities. Positive linear correlations were observed between the contents of the three tanshinones, whereas negative linear correlations were revealed between the contents of the tanshinones and salvianolic acid B. The highest root yield per plant pair was achieved when the plants were grown at 45×30 cm or 45×40 cm, whereas the highest root production par unit area was obtained for a plant density of 30×30 cm. The highest contents of the three tanshinones and the most abundant production of these tanshinones per unit area were achieved when the plants were grown at 30×30 cm. However, the highest content of salvianolic acid B was found for a density of 45×40 cm, while its highest yield per unit area was obtained for densities of 30×40 cm or 45×30 cm. The findings suggest that the plant density distinctly affects the root yield and content and the yield of tanshinones and salvianolic acid B in Australian grown S. miltiorrhiza, which may be used as a guide for developing optimal agricultural procedures for cultivating this herb.     

Ultrahigh diterpenoid tanshinone production through repeated osmotic stress and elicitor stimulation in fed-batch culture of <Emphasis Type="Italic">Salvia miltiorrhiza</Emphasis> hairy roots

Hyperosmotic stress (OS, created with 50 g/L sorbitol) and a yeast elicitor (YE, polysaccharide fraction of yeast extract) applied to Salvia miltiorrhiza hairy root cultures had a synergistic effect on the diterpenoid tanshinone production. With a single OS+YE treatment and nutrient feeding, the total tanshinone content of roots was increased by sevenfold (from 0.2 to 1.6 mg/g dry weight (dw)) and the volumetric yield by 13-fold (from 1.95 to 27.4 mg/L) compared to the batch control culture. With repeated feeding of OS and nutrient medium in an extended fed-batch culture process (i.e., 10 mL fresh medium with 50 g/L sorbitol 25 mg/L YE, every 5 days from day 21 to day 60), the total tanshinone content of roots was increased to 18.1 mg/g dw (or 1.8 wt.%) and the volumetric tanshinone yield to 145 mg/L, which were about 100-fold and 70-fold of those, respectively, in the batch control. Another interesting finding was the presence of root fragments (fine particles) with extremely high tanshinone content in the OS+YE treated cultures. It was also possible to reuse the sorbitol medium for the hairy root growth and tanshinone production to reduce the medium expenses.     

丹参醌化合物结构特征与抗氧化活性

对双氢丹参醌I和丹参醌Ⅱ在油脂中的抗氧化作用及构效关系进行了量子化学研究。结果表明 ,抗氧化剂与油脂中碳中心自由基 (R· )复合成稳定自由基 (AH -R· ) ,可能是丹参醌抑制或阻止油脂氧化酸败的主要途径 ,双氢丹参醌I也可借助释放活泼H(本身转化成稳定自由基A· )有效清除R·。丹参醌分子本身的化学活性和对应的AH -R·与A·的稳定性对此类抗氧化作用有重要影响。AH -R·和A·中自旋集居分布 ,对比较抗氧化剂的相对活性可能是一个有价值的电子结构参数。     

ortho-Quinone tanshinones directly inhibit telomerase through an oxidative mechanism mediated by hydrogen peroxide

The tanshinone natural products possess a variety of pharmacological properties including anti-bacterial, anti-inflammatory, anti-oxidant, and anti-neoplastic activity. The molecular basis of these effects, however, remains largely unknown. In the present study, we explored the direct effect of tanshinones on the enzyme telomerase. Telomerase is up-regulated in the majority of cancer cells and is essential for their survival, making it a potential anti-cancer drug target. We found that the ortho-quinone tanshinone II-A inhibits telomerase in a time- and DTT-dependent fashion, and the hydrogen peroxide scavenger catalase protected telomerase from inactivation. These findings demonstrate that ortho-quinone containing tanshinones can inhibit telomerase owing to their ability to generate reactive oxygen species. The results also provide evidence that telomerase is directly and negatively regulated by reactive oxygen species.     

Computational drug screening against the SARS-CoV-2 Saudi Arabia isolates through a multiple-sequence alignment approach

COVID-19 is a rapidly emerging infectious disease caused by the SARS-CoV-2 virus currently spreading throughout the world. To date, there are no specific drugs formulated for it, and researchers around the globe are racing against the clock to investigate potential drug candidates. The repurposing of existing drugs in the market represents an effective and economical strategy commonly utilized in such investigations. In this study, we used a multiple-sequence alignment approach for preliminary screening of commercially-available drugs on SARS-CoV sequences from the Kingdom of Saudi Arabia (KSA) isolates. The viral genomic sequences from KSA isolates were obtained from GISAID, an open access repository housing a wide variety of epidemic and pandemic virus data. A phylogenetic analysis of the present 164 sequences from the KSA provinces was carried out using the MEGA X software, which displayed high similarity (around 98%). The sequence was then analyzed using the VIGOR4 genome annotator to construct its genomic structure. Screening of existing drugs was carried out by mining data based on viral gene expressions from the ZINC database. A total of 73 hits were generated. The viral target orthologs were mapped to the SARS-CoV-2 KSA isolate sequence by multiple sequence alignment using CLUSTAL OMEGA, and a list of 29 orthologs with purchasable drug information was generated. The results showed that the SARS CoV replicase polyprotein 1a had the highest sequence similarity at 79.91%. Through ZINC data mining, tanshinones were found to have high binding affinities to this target. These compounds could be ideal candidates for SARS-CoV-2. Other matches ranged between 27 and 52%. The results of this study would serve as a significant endeavor towards drug discovery that would increase our chances of finding an effective treatment or prevention against COVID19.     

Molecular cloning,characterization and expression analysis of a new gene encoding 3-hydroxy-3-methylglutaryl coenzyme A reductase from <Emphasis Type="Italic">Salvia miltiorrhiza</Emphasis>

The 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) catalyzes the conversion of HMG-CoA to mevalonate (MVA), which is the first committed step in MVA pathway for isoprenoid biosynthesis in plants. In this study, a full-length cDNA encoding HMGR was isolated from Salvia miltiorrhiza by rapid amplification of cDNA ends (RACE) for the first time, which was designated as SmHMGR (GenBank Accession No.EU680958). The full-length cDNA of SmHMGR was 2,115 bp containing a 1,695 bp open reading frame (ORF) encoding a polypeptide of 565 amino acids. Bioinformatic analyzes revealed that the deduced SmHMGR had extensive homology with other plant HMGRs contained two transmembrane domains and a catalytic domain. Molecular modeling showed that SmHMGR is a new HMGR with a spatial structure similar to other plant HMGRs. Phylogenetic tree analysis indicated that SmHMGR belongs to the plant HMGR super-family and has the closest relationship with HMGR from Picrorhiza kurrooa. Expression pattern analysis implied that SmHMGR expressed highest in root, followed by stem and leaf. The expression of SmHMGR could be up-regulated by salicylic acid (SA) and methyl jasmonate (MeJA), suggesting that SmHMGR was elicitor-responsive. This work will be helpful to understand more about the role of HMGR involved in the tanshinones biosynthesis at the molecular level.