Phenolic compounds from Canna edulis Ker residue and their antioxidant activity

Application of Rosmarinic Acid with Its Derivatives in the Treatment of Microbial Pathogens

The emergence of the antimicrobial resistance phenomena on and the harmful consequences of the use of antibiotics motivate the necessity of innovative antimicrobial therapies, while natural substances are considered a promising alternative. Rosmarin is an original plant compound listed among the hydroxycinnamic acids. This substance has been widely used to fight microbial pathology and chronic infections from microorganisms like bacteria, fungi and viruses. Also, various derivatives of rosmarinic acid, such as the propyl ester of rosmarinic acid, rosmarinic acid methyl ester or the hexyl ester of rosmarinic acid, have been synthesized chemically, which have been isolated as natural antimicrobial agents. Rosmarinic acid and its derivatives were combined with antibiotics to obtain a synergistic effect. This review reports on the antimicrobial effects of rosmarinic acid and its associated derivatives, both in their free form and in combination with other microbial pathogens, and mechanisms of action.

A Comprehensive Review of Rosmarinic Acid: From Phytochemistry to Pharmacology and Its New Insight

Polyphenolic acids are the widely occurring natural products in almost each herbal plant, among which rosmarinic acid (RA, C18H16O8) is well-known, and is present in over 160 species belonging to many families, especially the Lamiaceae. Aside from this herbal ingredient, dozens of its natural derivatives have also been isolated and characterized from many natural plants. In recent years, with the increasing focus on the natural products as alternative treatments, a large number of pharmacological studies have been carried out to demonstrate the various biological activities of RA such as anti-inflammation, anti-oxidation, anti-diabetes, anti-virus, anti-tumor, neuroprotection, hepatoprotection, etc. In addition, investigations concerning its biosynthesis, extraction, analysis, clinical applications, and pharmacokinetics have also been performed. Although many achievements have been made in various research aspects, there still exist some problems or issues to be answered, especially its toxicity and bioavailability. Thus, we hope that in the case of natural products, the present review can not only provide a comprehensive understanding on RA covering its miscellaneous research fields, but also highlight some of the present issues and future perspectives worth investigating later, in order to help us utilize this polyphenolic acid more efficiently, widely, and safely.

Canna x generalis L.H. Bailey rhizome extract ameliorates dextran sulfate sodium-induced colitis via modulating intestinal mucosal dysfunction, oxidative stress, inflammation, and TLR4/ NF-ҡB and NLRP3 inflammasome pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Genus Canna is used in folk medicine as demulcent, diaphoretic, antipyretic, mild laxative and in gastrointestinal upsets therapy. Canna x generalis (CG) L.H. Bailey is traditionally used as anti-inflammatory, analgesic and antipyretic. Besides, CG is used in Ayurvedic medicines' preparations and in the treatment of boils, wounds, and abscess. Nevertheless, its anti-inflammatory effects against ulcerative colitis (UC) are not yet investigated.

AIM

This study aimed to investigate the phytoconstituents of CG rhizome ethanol extract (CGE). Additionally, we aimed to comparatively evaluate its therapeutic effects and underlying mechanisms against the reference drug "sulphasalazine (SAS)" in dextran sodium sulfate (DSS)-induced UC in mice.

MATERIAL AND METHODS

Metabolic profiling of CG rhizomes was performed via UHPLC/qTOF-HRMS; the total phenolic, flavonoid and steroid contents were determined, and the main phytoconstituents were isolated and identified. Next, DSS-induced (4%) acute UC was established in C57BL/6 mice. DSS-induced mice were administered either CGE (100 and 200 mg/kg) or SAS (200 mg/kg) for 7 days. Body weight, colon length, disease activity index (DAI) and histopathological alterations in colon tissues were examined. Colon levels of oxidative stress (GSH, MDA, SOD and catalase) and pro-inflammatory [Myeloperoxidase (MPO), nitric oxide (NO), IL-1β, IL-12, TNF-α, and INF-γ] markers were colourimetrically determined. Serum levels of lipopolysaccharide (LPS) and relative mRNA expressions of occludin, TLR4 and ASC (Apoptosis-Associated Speck-Like Protein Containing CARD) using RT-PCR were measured. Protein levels of NLRP3 inflammasome and cleaved caspase-1 were determined by Western blot. Furthermore, immunohistochemical examinations of caspase-3, NF-ҡB and claudin-1 were performed.

RESULTS

Major identified constituents of CGE were flavonoids, phenolic acids, phytosterols, beside five isolated phytoconstituents (β-sitosterol, triacontanol fatty alcohol, β-sitosterol-3-O-β-glucoside, rosmarinic acid, 6-O-p-coumaroyl-β-D-fructofuranosyl α-D-glucopyranoside). The percentage of the phenolic, flavonoid and steroid contents in CGE were 20.55, 6.74 and 98.09 μg of gallic acid, quercetin and β-sitosterol equivalents/mg extract, respectively. In DSS-induced mice, CGE treatment ameliorated DAI, body weight loss and colon shortening. CGE attenuated the DSS-induced colonic histopathological alternations, inflammatory cell infiltration and histological scores. CGE elevated GSH, SOD and catalase levels, and suppressed MDA, pro-inflammatory mediators (MPO and NO) as well as cytokines levels in colonic tissues. Moreover, CGE downregulated LPS/TLR4 signaling, caspase-3 and NF-ҡB expressions. CGE treatment inhibited NLRP3 signaling pathway as indicated by the suppression of the protein expression of NLRP3 and cleaved caspase-1, and the ASC mRNA expression in colonic tissues. Additionally, CGE restored tight junction proteins' (occludin and claudin-1) expressions.

CONCLUSION

Our findings provided evidence for the therapeutic potential of CGE against UC. CGE restored intestinal mucosal barrier's integrity, mitigated oxidative stress, inflammatory cascade, as well as NF-ҡB/TLR4 and NLRP3 pathways activation in colonic tissues. Notably, CGE in a dose of 200 mg/kg was more effective in ameliorating DSS-induced UC as compared to SAS at the same dose.

Inhibitory effect on human platelet aggregation and coagulation and antioxidant activity of C. edulis Ker Gawl rhizome and its secondary metabolites

ETHNOPHARMACOLOGICAL RELEVANCE

Although Canna edulis Ker Gawl rhizome has been used in Traditional Vietnamese Medicine to prevent and treat heart diseases without thorough scientific evidence, limited intensive search for the bioactivities and useful substances has been done.

AIM OF THE STUDY

This study aims to investigate the antiplatelet aggregation, anticoagulant and antioxidant activity of extracts from C. edulis rhizome, separate and purify its compounds from the most active fraction and evaluate the antiplatelet aggregation, anticoagulant and antioxidant activity of isolated compounds.

MATERIALS AND METHODS

C. edulis rhizome was extracted with ethanol, then fractionated with n-hexane, ethyl acetate and water. The inhibitory effect on adenosine diphosphate- and collagen-induced human platelet aggregation was evaluated. Prothrombin time, activated partial thromboplastine time and thrombine time were measured to examine the anticoagulant activity. The free radical scavenging ability was assessed with DPPH and ABTS assays. The fraction that showed the most active was used to separate and purify compounds. The structures of compounds were elucidated by NMR and MS spectroscopic methods. Isolated compounds were also tested for antiplatelet, anticoagulant and antioxidant activity.

RESULTS

The ethyl acetate fraction showed the most potent antiplatelet aggregation, anticoagulant and antioxidant activity. Subsequent fractionation of this active fraction resulted in the isolation of seven known compounds: 5-hydroxy-6-methyl-2H-pyran-2-one (1), epimedokoreanone A (2), nepetoidin B (3), ferulic acid (4), caffeic acid (5), hydroxytyrosol (6), and 1H-indole-3-carboxaldehyde (7). Previous studies reported the antiplatelet, anticoagulant and antioxidant activity of ferulic acid (4), caffeic acid (5) and hydroxytyrosol (6) and the antioxidant activity of nepetoidin B (3). This study demonstrated that both epimedokoreanone A (2) and nepetoidine B (3) also exhibited good antiplatelet effect and epimedokoreanone A (2) also had effective anticoagulant and antioxidant activity, while 5-hydroxy-6-methyl-2H-pyran-2-one (1) showed weaker antiplatelet and antioxidant activity but no anticoagulant effect.

CONCLUSIONS

This is the first experimental study to demonstrate the potent dose-dependent antiplatelet aggregation, anticoagulant and antioxidant activity of C. edulis rhizome and its pure compounds, supporting the traditional use of this plant for the treatment of heart diseases. The C. edulis rhizome is a potential source of bioactive compounds or functional food for treatment and/or prevention of heart- and oxidative stress-related diseases and its bioactive compounds are good candidates for drug development of anti-thrombosis and antioxidant agents.

Morphological, physico-chemical and functional properties of underutilized starches in China

In this study, starches were isolated from different non-conventional sources (acorn, black wheat, buckwheat, coix seed, jiaoyu, kuzhu, longya lily, and naked oat) cultivated in China, and their morphological, physico-chemical, and functional properties were analyzed. Among isolated starches, significant differences (p < 0.05) were observed in morphology, pasting, crystallinity, physico-chemical, and functional properties. After a comparison with commercial corn starch, all these isolated starches presented promising and unique characteristics. The XRD profile of isolated starches presented A-type (naked oat, buckwheat, coix seed, and black wheat), B-type (longya lily, acorn and jiaoyu) and C-type (kuzhu) polymorphic structures. SEM analysis revealed that the starches isolated from different sources showed distinct shapes exclusively globular, elliptic, and polygonal shapes. The high viscosity of jiaoyu and kuzhu starch pastes can be utilized to have an advantage in instant soups and sauces. Hence, the present study will improve the scientific basis on starches from different non-conventional sources, facilitate their utilization in a variety of applications.