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    ABSTRACT: Salacia reticulata (SR) is a plant native to Sri Lanka. In ayurvedic medicine, SR bark preparations, taken orally, are considered effective in the treatment of rheumatism and diabetes. We investigated the ability of SR leaves (SRL) to inhibit in vitro the interleukin-1β (IL-1β)-activated proliferation of synoviocyte-like cells derived from rheumatoid arthritis model mice. Inflammatory synovial tissues were harvested from type II collagen antibody-induced arthritic mice. From these tissues, a synoviocyte-like cell line was established and named MTS-C H7. To determine whether SRL can suppress cell proliferation and gene expression in MTS-C H7 cells, fractionation of the SRL hot-water extract was performed by high-performance liquid chromatography (HPLC), liquid-liquid extraction, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), and protease digestion.The 50% inhibitory concentration of the SRL hot-water extract against MTS-C H7 cells proliferation was ~850 μg/mL. Treatment with a low dose (25 μg dry matter per millilitre) of the extract inhibited IL-1β-induced cell proliferation and suppressed the expression of the matrix metalloproteinase (MMP) genes in MTS-C H7 cells. Various polyphenolic fractions obtained from HPLC and the fractions from liquid-liquid extraction did not affect cell proliferation. Only the residual water sample from liquid-liquid extraction significantly affected cell proliferation and the expression of MMP genes. The results of SDS-PAGE and protease digestion experiment showed that low molecular weight proteins present in SRL inhibited the IL-1β-activated cell proliferation. We surmised that the residual water fraction of the SRL extract was involved in the inhibition of IL-1β-activated cell proliferation and regulation of mRNA expression in MTS-C H7 cells. In addition, we believe that the active ingredients in the extract are low molecular weight proteins.
    BMC Research Notes 04/2012; 5:198. DOI:10.1186/1756-0500-5-198
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    ABSTRACT: The use of traditional/complementary/alternate medicines (TCAMs) in HIV/AIDS patients who reside in Southern Africa is quite common. Those who use TCAMs in addition to antiretroviral (ARV) treatment may be at risk of experiencing clinically significant pharmacokinetic (PK) interactions, particularly between the TCAMs and the protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs). Mechanisms of PK interactions include alterations to the normal functioning of drug efflux transporters, such as P-gp and/or CYP isoenzymes, such a CYP3A4 that mediate the absorption and elimination of drugs in the small intestine and liver. Specific mechanisms include inhibition and activation of these proteins and induction via the pregnane X receptor (PXR). Several clinical studies and case reports involving ARV-herb PK interactions have been reported. St John's Wort, Garlic and Cat's Claw exhibited potentially significant interactions, each with a PI or NNRTI. The potential for these herbs to induce PK interactions with drugs was first identified in reports of in vitro studies. Other in vitro studies have shown that several African traditional medicinal (ATM) plants and extracts may also demonstrate PK interactions with ARVs, through effects on CYP3A4, P-gp and PXR. The most complex effects were exhibited by Hypoxis hemerocallidea, Sutherlandia frutescens, Cyphostemma hildebrandtii, Acacia nilotica, Agauria salicifolia and Elaeodendron buchananii. Despite a high incidence of HIV/AIDs in the African region, only one clinical study, between efavirenz and Hypoxis hemerocallidea has been conducted. However, several issues/concerns still remain to be addressed and thus more studies on ATMs are warranted in order for more meaningful data to be generated and the true potential for such interactions to be determined.
    Biopharmaceutics & Drug Disposition 11/2011; 32(8):458-70. DOI:10.1002/bdd.775 · 2.18 Impact Factor
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    ABSTRACT: A plethora of active compounds found in herbal medicines can serve as substrate for enzymes involved in the metabolism of xenobiotics. When a medicinal plant is co-administered with a conventional drug and little or no information is known about the pharmacokinetics of the plant metabolites, there is an increased risk of potential herb-drug interactions. Moreover, genetic polymorphisms in a population may act to predispose individuals to adverse reactions. The use of herbal medicines is rapidly increasing in many countries, particularly Brazil where the vast biodiversity is a potential source of new and more affordable treatments for numerous conditions. Accordingly, the Brazilian Unified Public Health System (SUS) produced a list of 71 plant species of interest, which could be made available to the population in the near future. Physicians at SUS prescribe a number of essential drugs and should herbal medicines be added to this system the chance of herb-drug interactions further increases. A review of the effects of these medicinal plants on Phase 1 and Phase 2 metabolic mechanisms and the transporter P-glycoprotein was conducted. The results have shown that approximately half of these medicinal plants lack any pharmacokinetic data. Moreover, most of the studies carried out are in vitro. Only a few reports on herb-drug interactions with essential drugs prescribed by SUS were found, suggesting that very little attention is being given to the safety of herbal medicines. Here we have taken this information to discuss the potential interactions between herbal medicines and essential drugs prescribed to Brazilian patients whilst taking into account the most common polymorphisms present in the Brazilian population. A number of theoretical interactions are pinpointed but more pharmacokinetic studies and pharmacovigilance data are needed to ascertain their clinical significance.
    Frontiers in Pharmacology 06/2014; 5:162. DOI:10.3389/fphar.2014.00162