Synergistic effect of Trikatuk, a traditional Thai formulation, on antioxidant and alpha-glucosidase inhibitory activities.

Oxidative stress and hyperglycemia are known to be responsible for several diseases, including diabetes. To prevent these diseases, efforts are ongoing to identify novel antioxidants with hypoglycemic effects. Trikatuk is a traditional Thai formulation composed of three herbs in equal quantities: the fruits of Piper nigrum and Piper retrofractum and the rhizomes of Zingiber officinale. This formulation has been reported to have antioxidant activity and the three individual herbs have been traditionally used for managing diabetes. Therefore, the present study aimed to investigate the phytochemical contents, antioxidant activity (DPPH and ABTS radical scavenging assays), and alpha-glucosidase inhibitory activity of Trikatuk. As Trikatuk is a combination of herbs, the synergistic effect and two different preparation methods from powder or extract mixtures were also explored. The results revealed that Trikatuk, particularly prepared from a mixture of extracts, exhibited high contents of piperine, total phenolics and total flavonoids, as well as significant antioxidant and alpha-glucosidase inhibitory activities. Trikatuk also exhibited additive or synergistic effects in all experiments. Overall, Trikatuk is potentially an alternative traditional medicine and dietary supplement offering antioxidant activity and diabetes management.

A review on benefits of quercetin in hyperuricemia and gouty arthritis.

Hyperuricemia becomes a public health problem worldwide. It is not only a major risk factor for gout but also associated with the development of life-threatening diseases such as chronic kidney disease and cardiovascular diseases. Although there are several available therapeutic drugs, some serious adverse effects and contraindications are concerned. These drive the search for an alternative therapy that is effective and safe. Quercetin is of particular interesting since it has been reported numerous pharmacological activities, especially anti-hyperuricemia, antioxidant, anti-inflammation and amelioration of metabolic syndromes and cardiovascular diseases which are comorbidities of hyperuricemia and gout. In addition, quercetin has been widely used as a health supplement for many diseases however, the use for hyperuricemia and gout has not been indicated. Therefore, this review aims to gather and summarize published data regarding the efficacy in preclinical and clinical studies along with possible mechanism of action, and safety aspect of quercetin in order to support the use of quercetin as a dietary supplement for prevention and management of hyperuricemia and gouty arthritis and/or use as alternative or combination therapy to minimize the side effects of the conventional drugs.

Speed of action and stage specificity of Bencha-loga-wichian, a Thai traditional antipyretic formulation, against Plasmodium falciparum and the chloroquine-potentiating activity of its active compounds, tiliacorinine and yanangcorinine.

ETHNOPHARMACOLOGICAL RELEVANCE: Bencha-loga-wichian (BLW), a Thai traditional antipyretic formulation, has been reported to have promising antiplasmodial activity, and it was previously revealed that tiliacorinine and yanangcorinine, isolated from Tiliacora triandra, were the active compounds. However, the mechanisms of action of BLW have not been investigated. In addition, these active compounds are bisbenzylisoquinoline alkaloids, many compounds of which have been reported to potentiate the efficacy of chloroquine. AIMS OF THE STUDY: To investigate the antiplasmodial mechanisms of action of BLW and evaluate the effects of chloroquine combined with tiliacorinine or yanangcorinine. MATERIALS AND METHODS: Chloroquine-resistant Plasmodium falciparum (PfW2) strains at the ring, trophozoite, and schizont stages were exposed to the extracts or compounds for 2, 4, 6, 8, 10, 12, 24 or 48 h. The percentages of parasitemia were determined by flow cytometry, and their morphologies were examined by Giemsa-stained smear to evaluate the speed of action and stage specificity. For the drug combination assay, a modified fixed-ratio isobologram method was used. RESULTS: The antiplasmodial activity of BLW possessed a slow onset of action and was the most effective against ring-stage parasites. After 48 h of extracts or compounds exposure, most of the treated parasites, at all stages, turned to the pyknotic form and could not recover even after extracts or compounds removal. The results suggested that these extracts and compounds could kill the parasites or possess parasiticidal effects. In addition, the combination of chloroquine with tiliacorinine or yanangcorinine demonstrated a synergistic effect, indicating that these compounds could potentiate chloroquine efficacy against chloroquine-resistant parasites. CONCLUSION: The antiplasmodial mechanisms of action of BLW appeared to differ from that of chloroquine and other current antimalarial drugs. In addition, tiliacorinine and yanangcorinine, the active compounds of BLW, could potentiate the efficacy of chloroquine. Accordingly, BLW was shown to be a good candidate for development as a new antimalarial and useful for drug combination therapy.

Antiplasmodial activities of a Thai traditional antipyretic formulation, Bencha-Loga-Wichian: A comparative study between the roots and their substitutes, the stems.

ETHNOPHARMACOLOGICAL RELEVANCE: Bencha-Loga-Wichian (BLW) is a polyherbal antipyretic formulation that is comprised of Capparis micracantha, Clerodendrum indicum, Ficus racemosa, Harrisonia perforata, and Tiliacora triandra. A traditional medical textbook has documented the use of this formulation for the treatment of many types of fever, including malaria-like fever. Traditionally, BLW is composed of the root parts of those plants. However, in current practice, the stem parts are frequently substituted. Thus, this study aimed to evaluate the antiplasmodial activities of BLW and compare the efficacy between the stem and root parts. MATERIALS AND METHODS: BLW formulations produced from either the stem or root parts of the various constituent plants as well as the stems or roots of the individual plants were separately extracted and tested against the chloroquine-sensitive (Pf3D7) and -resistant (PfW2) strains Plasmodium falciparum using flow cytometry. The cytotoxicity against peripheral blood mononuclear cells was evaluated using the WST-8 assay to determine the selectivity index (SI). The active compounds of BLW were isolated using antiplasmodial-guided isolation and quantified using Ultra-Performance Liquid Chromatography (UPLC). RESULTS: The stem and root parts of BLW and the individual plants exhibited antiplasmodial activities at the same levels with good SI values in the range of 3.55-19.74. The extracts of BLW exhibited promising antiplasmodial activity against both Pf3D7 (IC50<5µg/mL) and PfW2 (IC50=6-10µg/mL). Among the five component plants, T. triandra was the most active and exhibited an IC50<5µg/mL against both strains of parasites with SI values >10. We isolated tiliacorinine and yanangcorinine as the major active compounds (IC50<2µg/mL). However, these two compounds demonstrated cytotoxic effects (SI<1). The UPLC analysis identified these compounds in both the stem and root parts of BLW in the range of 0.57-7.66%, which correlated with the antiplasmodial activity. The concentrations of these compounds in BLW, at comparable efficacy, were much less than those at the IC50s for the single compounds alone. It suggested that synergistic interactions increased the antiplasmodial effects as well as alleviated the toxicity of the active compounds in BLW. CONCLUSION: This study described a promising antiplasmodial activity of BLW that had good selectivity and a toxicity-alleviating effect. The results provided scientific support for the use of this formulation for the treatment of malaria. In addition, the stem and root parts of the plants in BLW exhibited equivalent activities, which indicates the potential for the substitution of the stem parts in the formulation. Thus, we recommend additional study of the stem parts of these plants for further development on the basis of the availability and sustainability.