Displaying all 4 publications

  1. Ngo YL, Lau CH, Chua LS
    Food Chem Toxicol, 2018 Nov;121:687-700.
    PMID: 30273632 DOI: 10.1016/j.fct.2018.09.064
    Rosmarinic acid is a bioactive phytochemical that can be found in many herbs as ethnomedicines. It possesses remarkable pharmacological activities, and thus leading to its exploration as a therapeutic drug in diabetes treatment recently. This article reviews the extraction and fractionation techniques for plant-based natural rosmarinic acid and its anti-diabetic potential based on literature data published in journals, books, and patents from 1958 to 2017. Factors affecting the performance of rosmarinic acid extraction and fractionation such as operating temperature, time, solvent to sample ratio and eluent system are compiled and discussed in detail. The inhibitory action of rosmarinic acid against sugar digestive enzymes, and protective action towards pancreatic β-cell dysfunction and glucolipotoxicity mediated oxidative stress are also critically reviewed. The optimal parameters are largely dependent on the applied extraction and fractionation techniques, as well as the nature of plant samples. Previous studies have proven the potent role of rosmarinic acid to control plasma glucose level and increase insulin sensitivity in hyperglycemia. Although rosmarinic acid is readily absorbed by human body, its mechanism after consumption is remained unclear. Intensive studies should be well planned to determine the dosage and toxicity level of rosmarinic acid for efficacy and safe consumption.
    Matched MeSH terms: Depsides/chemistry
  2. Muhammad H, Gomes-Carneiro MR, Poça KS, De-Oliveira AC, Afzan A, Sulaiman SA, et al.
    J Ethnopharmacol, 2011 Jan 27;133(2):647-53.
    PMID: 21044879 DOI: 10.1016/j.jep.2010.10.055
    Orthosiphon stamineus, Benth, also known as Misai Kucing in Malaysia and Java tea in Indonesia, is traditionally used in Southeastern Asia to treat kidney dysfunctions, diabetes, gout and several other illnesses. Recent studies of Orthosiphon stamineus pharmacological profile have revealed antioxidant properties and other potentially useful biological activities thereby lending some scientific support to its use in folk medicine. So far the genotoxicity of Orthosiphon stamineus extracts has not been evaluated. In this study the genotoxic potential of Orthosiphon stamineus aqueous extract was investigated by the Salmonella/microsome mutation assay and the mouse bone marrow micronucleus test.
    Matched MeSH terms: Depsides/chemistry
  3. Pan Y, Abd-Rashid BA, Ismail Z, Ismail R, Mak JW, Pook PC, et al.
    Chem Biol Interact, 2011 Mar 15;190(1):1-8.
    PMID: 21276781 DOI: 10.1016/j.cbi.2011.01.022
    Orthosiphon stamineus (OS) has been traditionally used to treat diabetes, kidney and urinary disorders, high blood pressure and bone or muscular pain. To assess the possibility of drug-herb interaction via interference of metabolism, effects of four OS extracts of different polarity and three active constituents (sinensetin, eupatorin and rosmarinic acid) on major human cDNA-expressed cytochrome P450 (CYP) enzymes were investigated. Three substrate-probe based high-performance liquid chromatography (HPLC) assays were established to serve as activity markers for CYP2C9, CYP2D6 and CYP3A4. Our results indicate that OS extracts and constituents exhibited differential modulatory effects on different CYPs. While none of the OS components showed significant inhibition on CYP2C9, eupatorin strongly and uncompetitively inhibited CYP2D6 activity with a K(i) value of 10.2μM. CYP3A4 appeared to be the most susceptible enzyme to OS inhibitory effects. It was moderately inhibited by OS dichloromethane and petroleum ether extract with mixed-type and noncompetitive inhibitions (K(i)=93.7 and 44.9μg/mL), respectively. Correlation study indicated that the inhibition was accounted for by the presence of eupatorin in the extracts. When IC(50) values of these extracts were expressed in volume per dose unit to reflect inhibitory effect at recommended human doses from commercially available products, moderate inhibition was also observed. In addition, CYP3A4 was strongly and noncompetitively inhibited by eupatorin alone, with a K(i) value of 9.3μM. These findings suggest that co-administration of OS products, especially those with high eupatorin content, with conventional drugs may have the potential to cause drug-herb interactions involving inhibition of major CYP enzymes.
    Matched MeSH terms: Depsides/chemistry
  4. Chua LS, Lau CH, Chew CY, Ismail NIM, Soontorngun N
    Phytomedicine, 2018 Jan 15;39:49-55.
    PMID: 29433683 DOI: 10.1016/j.phymed.2017.12.015
    BACKGROUND: Orthosiphon aristatus (Blume) Miq. is a medicinal herb which is traditionally used for the treatment of diabetes and kidney diseases in South East Asia. Previous studies reported higher concentration of antioxidative phytochemicals, especially rosmarinic acid (ester of caffeic acid) and other caffeic acid derivatives in this plant extract than the other herbs such as rosemary and sage which are usually used as raw materials to produce rosmarinic acid supplement in the market.

    PURPOSE: The phytochemical profile of O. aristatus was investigated at different storage durations for quality comparison.

    METHODS: The phytochemicals were extracted from the leaves and stems of O. aristatus using a reflux reactor. The extracts were examined for total phenolic and flavonoid contents, as well as their antioxidant capacities, in terms of radical scavenging, metal chelating and reducing power. The phytochemical profiles were also analyzed by unsupervised principal component analysis and hierarchical cluster analysis, in relation to the factor of storage at 4 °C for 5 weeks.

    RESULTS: The leaf extract was likely to have more phytochemicals than stem extract, particularly caffeic acid derivatives including glycosylated and alkylated caffeic acids. This explains higher ratio of total phenolic content to total flavonoid content with higher antioxidant capacities for the leaf extracts. Rosmarinic acid dimer and salvianolic acid B appeared to be the major constituents, possibly contributing to the previously reported pharmacological properties. However, the phytochemical profiles were found changing, even though the extracts were stored in the refrigerator (4 °C). The change was significantly observed at the fifth week based on the statistical pattern recognition technique.

    CONCLUSION: O. aristatus could be a promising source of rosmarinic acid and its dimer, as well as salvianolic acid B with remarkably antioxidant properties. The phytochemical profile was at least stable for a month stored at 4 °C. It is likely to be a good choice of herbal tea with comparable radical scavenging activity, but lower caffeine content than other tea samples.

    Matched MeSH terms: Depsides/chemistry
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