A review of the bioactivity and potential health benefits of peppermint tea (Mentha piperita L.)

Menthol Enhances an Antiproliferative Activity of 1alpha,25-Dihydroxyvitamin D(3) in LNCaP Cells

1α,25-dihydroxyvitamin D₃ [1α,25(OH)₂D₃], the most active form of vitamin D₃, and its analogues have therapeutic benefits for prostate cancer treatment. However, the development of hypercalcemia is an obstacle to clinical applications of 1α,25(OH)₂D₃ for cancer therapy. In this study, we provide evidence that menthol, a key component of peppermint oil, increases an anti-proliferation activity of 1α,25(OH)₂D₃ in LNCaP prostate cancer cells. We found that menthol per se does not exhibit antiproliferative activity, but it is able to enhance 1α,25(OH)₂D₃-mediated growth inhibition in LNCaP cells. Fluorometric assays using Fura-2 showed that 1α,25(OH)₂D₃ does not induce acute Ca²⁺ response, whereas menthol evokes an increase in [Ca²⁺]_i, which suggests that cross-talks of menthol-induced Ca²⁺ signaling with 1α,25(OH)₂D₃-mediated growth inhibition pathways. In addition, Western blot analysis revealed that 1α,25(OH)₂D₃ and menthol cooperatively modulate the expression of bcl-2 and p21 which provides the insight into the molecular mechanisms underlying the enhanced 1α,25(OH)₂D₃-mediated growth inhibition by menthol. Thus, our findings suggest that menthol may be a useful natural compound to enhance therapeutic effects of 1α,25(OH)₂D₃.

Bioactivity and structure of biophenols as mediators of chronic diseases

Biophenols and their associated activity have generated intense interest. Current topics of debate are their bioavailability and bioactivity. It is generally assumed that their plasma concentrations are insufficient to produce the health benefits previously attributed to their consumption. However, data on localized in vivo concentrations are not available and many questions remain unanswered. Potential mechanisms by which they may exert significant bioactivity are discussed together with structure activity relationships. Biophenols are highly reactive species and they can react with a range of other compounds. Products of their reaction when functioning as antioxidants are examined.

Antimutagenicity of rosmarinic acid in Swiss mice evaluated by the micronucleus assay

Rosmarinic acid (RA) is a natural phenolic compound which presents different biological activities such as antitumor, antibacterial, anti-inflammatory, hepatoprotective and cardioprotective properties. In view of its important biological activities, the study of the effects of RA on genetic material becomes relevant. Thus, the objective of the present study was to evaluate the mutagenic and/or antimutagenic potential of RA on peripheral blood cells of Swiss mice using the micronucleus assay. Three doses of RA (50, 100 and 200 mg/kg body weight, b.w.) were used for the evaluation of its mutagenic potential. In the antimutagenicity assays, the different concentrations of RA were combined with the chemotherapeutic agent doxorubicin (DXR, 15 mg/kg b.w.). Peripheral blood samples were collected 24, 48 and 72 h after treatment for the evaluation of micronucleated polychromatic erythrocytes (MNPCEs). The results of the mutagenicity assays showed no increase in the frequency of micronuclei in animals treated with different concentrations of RA when compared to the negative controls. Treatment with different concentrations of RA combined with DXR revealed a significant reduction in the frequency of micronuclei compared to animals treated with DXR only. Although the mechanisms underlying the protective effect of RA are not completely understood, the putative antioxidant activity of RA might explain its effect on DXR mutagenicity.

Brazilian flora extracts as source of novel antileishmanial and antifungal compounds

Natural products have long been providing important drug leads for infectious diseases. Leishmaniasis is a protozoan parasitic disease found mainly in developing countries, and it has toxic therapies with few alternatives. Fungal infections have been the main cause of death in immunocompromised patients and new drugs are urgently needed. In this work, a total of 16 plant species belonging to 11 families, selected on an ethnopharmacological basis, were analyzed in vitro against Leishmania (L.) chagasi, Leishmania (L.) amazonensis, Candida krusei, and C. parapsilosis. Of these plant species, seven showed antifungal activity against C. krusei, five showed antileishmanial activity against L. chagasi and four against L. amazonensis, among them species of genus Plectranthus. Our findings confirm the traditional therapeutic use of these plants in the treatment of infectious and inflammatory disorders and also offer insights into the isolation of active and novel drug prototypes, especially those used against neglected diseases as Leishmaniasis.

Ethnoveterinary medicines used to treat endoparasites and stomach problems in pigs and pets in British Columbia, Canada

This paper documents the medicinal plants used to treat endoparasites and stomach problems in dogs, cats and pigs in British Columbia, Canada. Ethnoveterinary data was collected over a 6-month period in 2003. The majority of the information on pets came from 2 naturopaths, 10 herbalists, 5 dog trainers, breeders and pet shop owners, 9 holistic veterinarians and 6 of 27 organic farmers. Two pig farmers joined the study in the final stages. The following plants were used as anthelmintics: Artemisia cina O. Berg and C.F. Schmidt, Artemisia vulgaris L., Artemisia annua, Calendula officinalis L., Echinacea purpurea (L.) Moench (all Asteraceae), Mentha piperita L. and Salvia officinalis L. (Lamiaceae) (Allium sativum L. (Alliaceae), Cucurbita pepo L. (Cucurbitaceae), Eugenia caryophyllata Thunb (Myrtaceae), Gentiana lutea L. (Gentianaceae), Hydrastis canadensis L. (Ranunculaceae), Juglans nigra L. (Juglandaceae), Olea europaea L. (Oleaceae) and Ruta graveolens L. (Rutaceae)). Stomach problems were treated with: Achillea millefolium L. (Asteraceae), Aloe vera (L.) Burm. f. (Asphodelaceae), Elytrigia repens (L.) Desv. ex Nevski (Poaceae), Frangula purshiana (DC.) Cooper (Rhamnaceae), Juniperus communis L. (Cupressaceae), Melissa officinalis L. and M. piperita L. (Lamiaceae), Petroselinum crispum L. (Apiaceae), Plantago major L. and Plantago ovata Forssk. (Plantaginaceae) Rumex crispus L. and Rumex obtusifolius L. (Polygonaceae), Ulmus fulva Michx. (Ulmaceae) and Zingiber officinalis Roscoe (Zingiberaceae). There is insufficient information available to assess the anthelmintic efficacies of C. officinalis, Salvia officinalis, Eugenia caryophyllata and O. europaea; the other plants have mid- to high-level validity for their ethnoveterinary uses.