Bioactivity and chemical constituents of Rhoeo spathacea and Rhoeo discolor, with emphasis on Rhoeo spathacea

Rhoeo spathacea and Rhoeo discolor are two common ornamental plants from the Commelinaceae family, commonly grown in tropical countries including Malaysia and have been traditionally taken orally for the treatment of superficial mycoses, inflammations and gonorrhoea. Despite the ethnobotanical applications of both plants and their popularity as a beverage particularly in South America, relatively little work has been conducted on their bioactivity and chemical constituents, thus warranting further research into these aspects. The preliminary stages of bioactivity assessment involved the determination of the antioxidant, antibacterial, antiproliferative and anti-tyrosinase activity of the crude extracts of both species. It was found that crude R. spathacea leaf extracts exhibited superior antioxidant activity compared to crude R. discolor leaf extracts. In addition, R. spathacea exhibited antibacterial activity against S. aureus and MRSA, while the crude extracts of R. discolor were inactive against the bacteria strains tested. The antiproliferative activity of R. spathacea was observable, but considerably poor. Five solvents of increasing polarity were then used for solvent fractionation. For both species, the phenolic compounds were concentrated in the more polar methanol and water solvent fractions. The polar solvent fractions of R. spathacea exhibited antibacterial activity but R. discolor did not exhibit any antibacterial activity, cementing R. spathacea’s role as the primary plant for the project. The solvent-fractionated extracts of R. spathacea continued to show rather poor antiproliferative activity, but showed considerable tyrosinase inhibitory activity. Column chromatography was then conducted on these fractions using bioactivity-guided fractionation. However this method was found to be inefficient, requiring a lot of material and a long processing time for very little yield of bioactive compounds. A new and efficient method utilizing a single solvent system in lieu of sequential extraction was developed, reducing the number of pre-column chromatography steps from eighteen to three. The Diaion HP-20 stationary phase also proved to be effective at rapidly concentrating the more polar phytochemicals of interest. Its comparatively rapid flow rate, coupled with the vastly reduced number of steps in the earlier stages significantly sped up productiveness. The sub-fractions obtained from this new method showed vastly superior antioxidant and antibacterial activity compared to the previous method, indicating a higher concentration of bioactive phytochemicals extracted despite also taking less time to achieve. Using a combination of high pressure liquid chromatography (HPLC) analysis and mass spectrometry, 27 compounds were found in R. spathacea. NMR was conducted on a rhoeonin, which was successfully isolated. This is the first time the NMR for rhoeonin has ever been reported. NMR was also conducted on 3-(3,4-dihydroxyphenyl)lactic acid (danshensu), which was also found in R. spathacea. Danshensu is the primary active compound in Salvia miltiorrhiza, a traditional herb with cardiotonic properties. However, this compound had not been previously reported in journals to be present in R. spathacea. Lastly, two practical applications of R. spathacea leaves were tested. The first was the use of R. spathacea leaves as an herbal tea, in line with its ethnobotanical application. The antioxidant and antibacterial properties of two different forms of boiling water extracts, decoction and infusion, were compared to room temperature aqueous extracts and solvent extracts. It was found that both the decoction and infusion methods were equally viable extraction methods, comparable in bioactivity with the optimized solvent-extracted crude extract. The application of heat dramatically improved the phenolic content and resulting bioactivity. The second application was as a natural food colorant due to the presence of rhoeonin, an exceptionally stable triacylated anthocyanin. The colour of R. spathacea extracts was exceptionally stable even at relatively low acidity, and showed no significant changes in colour when tested in two food models, thus indicating great potential for future development as a natural food colorant

Bioactivity and chemical constituents of Rhoeo spathacea and Rhoeo discolor, with emphasis on Rhoeo spathacea

Rhoeo spathacea and Rhoeo discolor are two common ornamental plants from the Commelinaceae family, commonly grown in tropical countries including Malaysia and have been traditionally taken orally for the treatment of superficial mycoses, inflammations and gonorrhoea. Despite the ethnobotanical applications of both plants and their popularity as a beverage particularly in South America, relatively little work has been conducted on their bioactivity and chemical constituents, thus warranting further research into these aspects. The preliminary stages of bioactivity assessment involved the determination of the antioxidant, antibacterial, antiproliferative and anti-tyrosinase activity of the crude extracts of both species. It was found that crude R. spathacea leaf extracts exhibited superior antioxidant activity compared to crude R. discolor leaf extracts. In addition, R. spathacea exhibited antibacterial activity against S. aureus and MRSA, while the crude extracts of R. discolor were inactive against the bacteria strains tested. The antiproliferative activity of R. spathacea was observable, but considerably poor. Five solvents of increasing polarity were then used for solvent fractionation. For both species, the phenolic compounds were concentrated in the more polar methanol and water solvent fractions. The polar solvent fractions of R. spathacea exhibited antibacterial activity but R. discolor did not exhibit any antibacterial activity, cementing R. spathacea’s role as the primary plant for the project. The solvent-fractionated extracts of R. spathacea continued to show rather poor antiproliferative activity, but showed considerable tyrosinase inhibitory activity. Column chromatography was then conducted on these fractions using bioactivity-guided fractionation. However this method was found to be inefficient, requiring a lot of material and a long processing time for very little yield of bioactive compounds. A new and efficient method utilizing a single solvent system in lieu of sequential extraction was developed, reducing the number of pre-column chromatography steps from eighteen to three. The Diaion HP-20 stationary phase also proved to be effective at rapidly concentrating the more polar phytochemicals of interest. Its comparatively rapid flow rate, coupled with the vastly reduced number of steps in the earlier stages significantly sped up productiveness. The sub-fractions obtained from this new method showed vastly superior antioxidant and antibacterial activity compared to the previous method, indicating a higher concentration of bioactive phytochemicals extracted despite also taking less time to achieve. Using a combination of high pressure liquid chromatography (HPLC) analysis and mass spectrometry, 27 compounds were found in R. spathacea. NMR was conducted on a rhoeonin, which was successfully isolated. This is the first time the NMR for rhoeonin has ever been reported. NMR was also conducted on 3-(3,4-dihydroxyphenyl)lactic acid (danshensu), which was also found in R. spathacea. Danshensu is the primary active compound in Salvia miltiorrhiza, a traditional herb with cardiotonic properties. However, this compound had not been previously reported in journals to be present in R. spathacea. Lastly, two practical applications of R. spathacea leaves were tested. The first was the use of R. spathacea leaves as an herbal tea, in line with its ethnobotanical application. The antioxidant and antibacterial properties of two different forms of boiling water extracts, decoction and infusion, were compared to room temperature aqueous extracts and solvent extracts. It was found that both the decoction and infusion methods were equally viable extraction methods, comparable in bioactivity with the optimized solvent-extracted crude extract. The application of heat dramatically improved the phenolic content and resulting bioactivity. The second application was as a natural food colorant due to the presence of rhoeonin, an exceptionally stable triacylated anthocyanin. The colour of R. spathacea extracts was exceptionally stable even at relatively low acidity, and showed no significant changes in colour when tested in two food models, thus indicating great potential for future development as a natural food colorant

Multifunctional, sustainable, and biological non-ureolytic self-healing systems for cement-based materials

Microbially induced calcium carbonate (CaCO3) precipitation (MICP) has been investigated as a sustainable alternative to conventional concrete remediation methods for improving the mechanical properties and durability of concrete structures. To date, urea-dependent MICP is the most widely employed MICP pathway in biological self-healing concrete research as its use has resulted in efficient CaCO3 precipitation rates. NH3 is a byproduct of ureolysis, and can be hazardous to cementitious structures and the health of various species. Accordingly, non-ureolytic bacterial concrete self-healing systems have been developed as eco-friendly alternatives to urea-dependent self-healing systems. Non-ureolytic pathways can improve the physical properties of concrete samples and incorporate the use of waste materials; they have the potential to be cost-effective and sustainable. Moreover, they can be applied in terrestrial and marine environments. To date, research on non-ureolytic concrete self-healing systems has been scarce compared to that on ureolytic systems. This article discusses the advances and challenges in non-ureolytic bacterial concrete self-healing studies and highlights the directions for future research

The Ameliorative Effects of a Tocotrienol-Rich Fraction on the AGE-RAGE Axis and Hypertension in High-Fat-Diet-Fed Rats with Metabolic Syndrome

The clinical value of tocotrienols is increasingly appreciated because of the unique therapeutic effects that are not shared by tocopherols. However, their effect on metabolic syndrome is not well-established. This study aimed to investigate the effects of a tocotrienol-rich fraction (TRF) from palm oil in high-fat-diet-treated rats. Male, post-weaning Sprague Dawley rats were provided high-fat (60% kcal) diet for eight weeks followed by a TRF (60 mg/kg) treatment for another four weeks. Physical, metabolic, and histological changes were compared to those on control and high-fat diets respectively. High-fat feeding for eight weeks induced all hallmarks of metabolic syndrome. The TRF reversed systolic and diastolic hypertension, hypercholesterolemia, hepatic steatosis, impaired antioxidant defense, and myeloperoxidase hyperactivity triggered by the high-fat diet. It also conferred an inhibitory effect on protein glycation to reduce glycated hemoglobin A1c and advanced glycation end products (AGE). This was accompanied by the suppression of the receptor for advanced glycation end product (RAGE) expression in the liver. The treatment effects on visceral adiposity, glycemic control, triglyceride level, as well as peroxisome proliferator-activated receptor α and γ expression were negligible. To conclude, treatment with a TRF exhibited protective effects on the cardiovascular and liver health in addition to the amelioration of plasma redox imbalance and AGE-RAGE activation. Further investigation as a therapy for metabolic syndrome is therefore worthwhile

Increased susceptibility of post-weaning rats on high-fat diet to metabolic syndrome

The present study aimed to examine the effects of the types of high-calorie diets (high-fat and high-fat-high-sucrose diets) and two different developmental stages (post-weaning and young adult) on the induction of metabolic syndrome. Male, post-weaning and adult (3- and 8-week old, respectively) Sprague Dawley rats were given control, high-fat (60% kcal), and high-fat-high-sucrose (60% kcal fat + 30% sucrose water) diets for eight weeks (n = 6 to 7 per group). Physical, biochemical, and transcriptional changes as well as liver histology were noted. Post-weaning rats had higher weight gain, abdominal fat mass, fasting glucose, high density lipoprotein cholesterol, faster hypertension onset, but lower circulating advanced glycation end products compared to adult rats. This is accompanied by upregulation of peroxisome proliferator-activated receptor (PPAR) α and γ in the liver and receptor for advanced glycation end products (RAGE) in the visceral adipose tissue. Post-weaning rats on high-fat diet manifested all phenotypes of metabolic syndrome and increased hepatic steatosis, which are linked to increased hepatic and adipocyte PPARγ expression. Adult rats on high-fat-high-sucrose diet merely became obese and hypertensive within the same treatment duration. Thus, it is more effective and less time-consuming to induce metabolic syndrome in male post-weaning rats with high-fat diet compared to young adult rats. As male rats were selectively included into the study, the results may not be generalisable to all post-weaning rats and further investigation on female rats is required

Geraniin Ameliorates Hypertensive Vascular Remodelling in a Diet-Induced Obese Animal Model through Antioxidant and Anti-Inflammatory Effects

Geraniin, an ellagitannin, has shown a potent blood pressure-lowering effect in vivo. Therefore, this study aims to further characterize the ability of geraniin to attenuate hypertensive vascular dysfunction, a key feature of cardiovascular disease (CVD) development. Hypertension was induced in male Sprague-Dawley rats through feeding a high-fat diet (HFD) for eight weeks, followed by oral administration of 25 mg/kg/day geraniin for four weeks. The parameters of vascular dysfunction such as the structure and function of blood vessels as well as the vascular oxidative stress and inflammation were evaluated. The outcomes of geraniin-treated rats were compared with those of untreated rats on either a normal diet (ND) or HFD and with HFD-fed rats treated with captopril (40 mg/kg/day). We found that geraniin supplementation effectively ameliorated HFD-induced hypertension and abnormal remodelling of the thoracic aorta by suppressing excessive vascular superoxide (O2−) radical generation and overexpression of pro-inflammatory mediators in the circulating leukocytes. Furthermore, compared to the ND-fed rats, geraniin also independently promoted the significant enlargement of the thoracic aortic lumen for blood pressure reduction. Notably, the vascular benefits of geraniin were comparable to that of captopril. Collectively, these data suggest that geraniin can mitigate hypertensive vascular remodelling caused by overnutrition, which potentially abrogates the further development of CVDs

First reported case of Gilbertella persicaria in human stool: outcome of a community study from Segamat, Johor, Malaysia

Daniel Reidpath - ORCID: 0000-0002-8796-0420 https://orcid.org/0000-0002-8796-0420Item is not available in this repository.Species of fungi belonging to the order Mucorales can be found everywhere in the environment. Gilbertella persicaria, which belongs to this order, have often been isolated from fruits and in water systems. However, there has been no report of isolation of this fungus from human samples. During a gut mycobiome study, from the Segamat community, Gilbertella persicaria was isolated from a human fecal sample and was characterized through a series of morphological assessment, biochemical tests, and molecular techniques. The isolate produced a white velvety surface that turned grayish after 24 h. Although no biofilm production was observed, the results indicated that the isolate could form calcium oxalate crystals, produced urease, and was resistant to low pH. The isolate was sensitive to amphotericin but resistant to voriconazole and itraconazole. The features of this fungus that could help in its survival in the human gut are also discussed.https://doi.org/10.1007/s42770-020-00323-z51pubpub