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Author

Toshiyuki Tanaka

Bio: Toshiyuki Tanaka is an academic researcher from Gifu Pharmaceutical University. The author has contributed to research in topics: Sophora & Flavanone. The author has an hindex of 31, co-authored 162 publications receiving 4356 citations. Previous affiliations of Toshiyuki Tanaka include Kanazawa University & Indonesian Institute of Sciences.
Topics: Sophora, Flavanone, Xanthone, Isomerization, Pallidol


Papers
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Journal ArticleDOI
TL;DR: In this paper, the minimum inhibitory concentrations (MICs) of phytochemical flavanones to clinical isolates of MRSA were determined by a serial agar dilution method.

611 citations

Journal ArticleDOI
TL;DR: In this paper, extracts of Garcinia mangostana (Guttiferae) showing inhibitory effects against the growth of S. aureus NIHJ 209p were fractionated according to guidance obtained from bioassay and some of the components with activity against methicillin-resistant Staphylococcus Aureus (MRSA) were characterized.
Abstract: Extracts of Garcinia mangostana (Guttiferae) showing inhibitory effects against the growth of S. aureus NIHJ 209p were fractionated according to guidance obtained from bioassay and some of the components with activity against methicillin-resistant Staphylococcus aureus (MRSA) were characterized. One active isolate, alpha-mangostin, a xanthone derivative, had a minimum inhibitory concentration (MIC) of 1.57-12.5 micrograms mL-1. Other related xanthones were also examined to determine their anti-MRSA activity. Rubraxanthone, which was isolated from Garcinia dioica and has a structure similar to that of alpha-mangostin, had the highest activity against staphylococcal strains (MIC = 0.31-1.25 micrograms mL-1), an activity which was greater than that of the antibiotic vancomycin (3.13-6.25 micrograms mL-1). The inhibitory effect against strains of MRSA of two of the compounds when used in conjunction with other antibiotics was also studied. The anti-MRSA activity of alpha-mangostin was clearly increased by the presence of vancomycin; this behaviour was not observed for rubraxanthone. The strong in-vitro antibacterial activity of xanthone derivatives against both methicillin-resistant and methicillin-sensitive Staphylococcus aureus suggests the compounds might find wide pharmaceutical use.

204 citations

Journal ArticleDOI
TL;DR: Six xanthones from the pericarps of mangosteen, Garcinia mangostana, showed growth inhibitory effects of human leukemia cell line HL60, and alpha-mangostin showed complete inhibition at 10 microM through the induction of apoptosis.
Abstract: We examined the effects of six xanthones from the pericarps of mangosteen, Garcinia mangostana, on the cell growth inhibition of human leukemia cell line HL60. All xanthones displayed growth inhibitory effects. Among them, α-mangostin showed complete inhibition at 10 μM through the induction of apoptosis.

193 citations

Journal ArticleDOI
TL;DR: Three new stilbene oligomers were isolated from the stem bark of Vatica pauciflora and elucidated by means of spectroscopic data interpretation, especially HMBC and NOESY NMR experiments.
Abstract: Three new stilbene oligomers (1-3) were isolated from the stem bark of Vatica pauciflora. The structures of a resveratrol heptamer (pauciflorol D) (1), a resveratrol dimer (pauciflorol E) (2), and an indanone derivative (pauciflorol F) (3) were elucidated by means of spectroscopic data interpretation, especially HMBC and NOESY NMR experiments.

132 citations

Journal ArticleDOI
TL;DR: In this article, garcinol and isogarcinol from the pericarps of Garcinia purpurea (Guttiferae) were evaluated for their antibacterial activity against methicillin-resistant Staphylococcus aureus and showed the lowest minimum inhibitory concentration at 3.1-12.5μg/ml.
Abstract: Benzophenone derivatives, garcinol (1) and isogarcinol (2) isolated from the pericarps of Garcinia purpurea (Guttiferae), and xanthochymol (3) and a mixture of isoxanthochymol (4) cycloxanthochymol (5) from the pericarps of G. subelliptica were evaluated for their antibacterial activity against methicillin-resistant Staphylococcus aureus. Among them, 3 showed the lowest minimum inhibitory concentration at 3.1-12.5μg/ml. This concentration is nearly equal to that of the antibiotic, vancomycin.

123 citations


Cited by
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Journal ArticleDOI
TL;DR: The current status of botanical screening efforts, as well as in vivo studies of their effectiveness and toxicity, are summarized and the structure and antimicrobial properties of phytochemicals are addressed.
Abstract: The use of and search for drugs and dietary supplements derived from plants have accelerated in recent years. Ethnopharmacologists, botanists, microbiologists, and natural-products chemists are combing the Earth for phytochemicals and “leads” which could be developed for treatment of infectious diseases. While 25 to 50% of current pharmaceuticals are derived from plants, none are used as antimicrobials. Traditional healers have long used plants to prevent or cure infectious conditions; Western medicine is trying to duplicate their successes. Plants are rich in a wide variety of secondary metabolites, such as tannins, terpenoids, alkaloids, and flavonoids, which have been found in vitro to have antimicrobial properties. This review attempts to summarize the current status of botanical screening efforts, as well as in vivo studies of their effectiveness and toxicity. The structure and antimicrobial properties of phytochemicals are also addressed. Since many of these compounds are currently available as unregulated botanical preparations and their use by the public is increasing rapidly, clinicians need to consider the consequences of patients self-medicating with these preparations.

7,486 citations

Journal ArticleDOI
TL;DR: Several high-quality investigations have examined the relationship between flavonoid structure and antibacterial activity and these are in close agreement, and future studies may allow the development of a pharmacologically acceptable antimicrobial agent or class of agents.

3,630 citations

Journal ArticleDOI
TL;DR: A comprehensive and critical review of the in vivo data on resveratrol is provided, and its potential as a therapeutic for humans is considered.
Abstract: Resveratrol, a constituent of red wine, has long been suspected to have cardioprotective effects. Interest in this compound has been renewed in recent years, first from its identification as a chemopreventive agent for skin cancer, and subsequently from reports that it activates sirtuin deacetylases and extends the lifespans of lower organisms. Despite scepticism concerning its bioavailability, a growing body of in vivo evidence indicates that resveratrol has protective effects in rodent models of stress and disease. Here, we provide a comprehensive and critical review of the in vivo data on resveratrol, and consider its potential as a therapeutic for humans.

3,509 citations

Journal ArticleDOI
TL;DR: Some of the recent advances in flavonoid research are reviewed and the role of anthocyanins and flavones in providing stable blue flower colours in the angiosperms is outlined.

3,465 citations

Journal ArticleDOI
TL;DR: Current trends of research and development activities on flavonoid relate to isolation, identification, characterisation and functions of flavonoids and finally their applications on health benefits and future research directions are discussed.
Abstract: Flavonoids, a group of natural substances with variable phenolic structures, are found in fruits, vegetables, grains, bark, roots, stems, flowers, tea and wine. These natural products are well known for their beneficial effects on health and efforts are being made to isolate the ingredients so called flavonoids. Flavonoids are now considered as an indispensable component in a variety of nutraceutical, pharmaceutical, medicinal and cosmetic applications. This is attributed to their anti-oxidative, anti-inflammatory, anti-mutagenic and anti-carcinogenic properties coupled with their capacity to modulate key cellular enzyme function. Research on flavonoids received an added impulse with the discovery of the low cardiovascular mortality rate and also prevention of CHD. Information on the working mechanisms of flavonoids is still not understood properly. However, it has widely been known for centuries that derivatives of plant origin possess a broad spectrum of biological activity. Current trends of research and development activities on flavonoids relate to isolation, identification, characterisation and functions of flavonoids and finally their applications on health benefits. Molecular docking and knowledge of bioinformatics are also being used to predict potential applications and manufacturing by industry. In the present review, attempts have been made to discuss the current trends of research and development on flavonoids, working mechanisms of flavonoids, flavonoid functions and applications, prediction of flavonoids as potential drugs in preventing chronic diseases and future research directions.

2,879 citations