Katsuhiro Yamasaki

Bio: Katsuhiro Yamasaki is an academic researcher from Osaka University of Pharmaceutical Sciences. The author has contributed to research in topics: Prunella vulgaris & Perilla frutescens. The author has an hindex of 3, co-authored 3 publications receiving 264 citations.

Anti-HIV-1 Activity of Herbs in Labiatae

Abstract: The anti-HIV-1 activity of aromatic herbs in Labiatae was evaluated in vitro. Forty five extract from among 51 samples obtained from 46 herb species showed significant inhibitory effects against HIV-1 induced cytopathogenicity in MT-4 cells. In particular, the aqueous extracts of Melissa officinalis, a family of Mentha×piperita "grapefruit mint", Mentha×piperita var. crispa, Ocimum basilicum cv "cinnamon", Perilla frutescens var. crispa f.viridis, Prunella vulgaris subsp. asiatica and Satureja montana showed potent anti-HIV-1 activity (with an ED of 16μg/ml). The active components in the extract samples were found to be water-solubel polar substances, not nonpolar compounds such as essential oils. In addition, these aqueous extracts inhibited giant cell formation in co-culture of Molt-4 cels with and without HIV-1 infection and showed inhibitory activity against HIV-1 reverse transcriptase.

[Screening test of crude drug extract on anti-HIV activity].

Abstract: The anti-HIV-1 effects of 204 crude drugs of common use in Japan were evaluated in vitro. As a result, 45 samples inhibited HIV-1-induced cytopathogenicity in MT-4 cells. In particular, the hot water extracts of Lithospermum erythrorhizon (root) and Prunella vulgaris (spike) showed the strongest anti-HIV-1 activities. Their IC100 values were both 16 micrograms/ml. In general, the hot water extracts of the crude drug suppressed the replication of HIV-1 growth more strongly than the cold water extracts.

Novel antiviral agents: a medicinal plant perspective

Abstract: Several hundred plant and herb species that have potential as novel antiviral agents have been studied, with surprisingly little overlap. A wide variety of active phytochemicals, including the flavonoids, terpenoids, lignans, sulphides, polyphenolics, coumarins, saponins, furyl compounds, alkaloids, polyines, thiophenes, proteins and peptides have been identified. Some volatile essential oils of commonly used culinary herbs, spices and herbal teas have also exhibited a high level of antiviral activity. However, given the few classes of compounds investigated, most of the pharmacopoeia of compounds in medicinal plants with antiviral activity is still not known. Several of these phytochemicals have complementary and overlapping mechanisms of action, including antiviral effects by either inhibiting the formation of viral DNA or RNA or inhibiting the activity of viral reproduction. Assay methods to determine antiviral activity include multiple-arm trials, randomized crossover studies, and more compromised designs such as nonrandomized crossovers and pre- and post-treatment analyses. Methods are needed to link antiviral efficacy/potency- and laboratory-based research. Nevertheless, the relative success achieved recently using medicinal plant/herb extracts of various species that are capable of acting therapeutically in various viral infections has raised optimism about the future of phyto-antiviral agents. As this review illustrates, there are innumerable potentially useful medicinal plants and herbs waiting to be evaluated and exploited for therapeutic applications against genetically and functionally diverse viruses families such as Retroviridae, Hepadnaviridae and Herpesviridae

A review of the bioactivity and potential health benefits of peppermint tea (mentha piperita l.)

Abstract: Peppermint (Mentha piperita L.) is one of the most widely consumed single ingredient herbal teas, or tisanes. Peppermint tea, brewed from the plant leaves, and the essential oil of peppermint are used in traditional medicines. Evidence-based research regarding the bioactivity of this herb is reviewed. The phenolic constituents of the leaves include rosmarinic acid and several flavonoids, primarily eriocitrin, luteolin and hesperidin. The main volatile components of the essential oil are menthol and menthone. In vitro, peppermint has significant antimicrobial and antiviral activities, strong antioxidant and antitumor actions, and some antiallergenic potential. Animal model studies demonstrate a relaxation effect on gastrointestinal (GI) tissue, analgesic and anesthetic effects in the central and peripheral nervous system, immunomodulating actions and chemopreventive potential. Human studies on the GI, respiratory tract and analgesic effects of peppermint oil and its constituents have been reported. Several clinical trials examining the effects of peppermint oil on irritable bowel syndrome (IBS) symptoms have been conducted. However, human studies of peppermint leaf are limited and clinical trials of peppermint tea are absent. Adverse reactions to peppermint tea have not been reported, although caution has been urged for peppermint oil therapy in patients with GI reflux, hiatal hernia or kidney stones.

Labiatae Family in folk Medicine in Iran: from Ethnobotany to Pharmacology

Abstract: Labiatae family is well represented in Iran by 46 genera and 410 species and subspecies. Many members of this family are used in traditional and folk medicine. Also they are used as culinary and ornamental plants. There are no distinct references on the ethnobotany and ethnopharmacology of the family in Iran and most of the publications and documents related to the uses of these species are both in Persian and not comprehensive. In this article we reviewed all the available publication on this family. Also documentation from unpublished resources and ethnobotanical surveys has been included. Based on our literature search, out of the total number of the Labiatae family in Iran, 18% of the species are used for medicinal purposes. Leaves are the most used plant parts. Medicinal applications are classified into 13 main categories. A number of pharmacological and experimental studies have been reviewed, which confirm some of the traditional applications and also show the headline for future works on this family.

Cellular pharmacology studies of shikonin derivatives.

Abstract: The naphthoquinone pigment, shikonin, isolated from Lithospermum erythrorhizon Sieb. et Zucc.(Boraginaceae) and its derivatives are the active components isolated from the Chinese herbal therapeutic, Zicao. Historically, Zicao root extracts have been used to treat macular eruption, measles, sore-throat, carbuncles and burns. Multiple pharmacological actions have been attributed to shikonin, e.g. antiinflammatory, antigonadotropic and anti-HIV-1 activity. In this review, several therapeutic applications of shikonin will be summarized including its pleiotropic, antiinflammatory and antitumour effects. Widely diverse and sometimes conflicting activities have been attributed to shikonin, e.g. wound healing, enhanced granuloma formation, suppression of local acute inflammatory reactions, inhibition of angiogenesis, inhibition of select chemokine ligands, inhibition of DNA topoisomerase activity, inhibition of platelet activation and antimicrobial activity. Comparison of the various reported mechanisms of action for shikonin lead us to hypothesize that shikonin is an effective inhibitor of protein-protein interaction with multiple targets in both the intracellular and extracellular compartments. This general inhibitory effect can account for the broad spectrum of shikonin biological and pharmacological activities.