TAKASHI WATANABE

Prof. Dr. TAKASHI WATANABE

Department of Medicinal Plant, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
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Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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19 October 2018 in BMC Complementary and Alternative Medicine
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SESara Mustafa Idris Elbashir
Sara Mustafa Idris Elbashir
Hari Prasad DevkotaHari Prasad Devkota
Hari Prasad Devkota
MWMikiyo Wada
Mikiyo Wada
NKNaoki Kishimoto
Naoki Kishimoto
MMMasataka Moriuchi
Masataka Moriuchi
TAKASHI WATANABETAKASHI WATANABE
TAKASHI WATANABE
Lifestyle-related diseases such as diabetes are steadily increasing worldwide. In Sudan, there are a variety of plant species used traditionally for the treatment of diabetes, obesity and other symptoms which need to be validated through scientific studies for their claimed traditional uses. Therefore, in the current study, the free radical scavenging activity, α-glucosidase inhibitory and pancreatic lipase inhibitory activities of 70% ethanol and water extracts of eighteen Sudanese medicinal plants were investigated using various in vitro assays. Moreover, the cytotoxicity and genotoxicity were assessed for the bioactive plant extracts. Eighteen plants were selected on the basis of their traditional uses and extracted with 70% ethanol and water to obtain thirty-six extracts. The obtained extracts were screened using different in vitro bioassays namely, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, α-glucosidase inhibitory and pancreatic lipase inhibitory assays. Furthermore, the active plant extracts were investigated for their cytotoxicity and genotoxicity on HeLa cell line using HCS DNA Damage Assay. Both 70% ethanol and water extracts of Acacia nilotica, Ziziphus spina-christi, Abrus precatorius, and Geigeria alata along with the 70% ethanol extract of Martynia annua showed potent free radical scavenging activity. Regarding the α-glucosidase inhibition assay, both extracts of Acacia nilotica, Ziziphus spina-christi, Geigeria alata, and Cyperus rotundus showed potent activity. In general, 70% ethanol extracts were more potent compared to water extracts with exception of Cordia sinensis and Cymbopogon proximus, for which water extracts also showed potent enzyme inhibitory activity. Similarly, water extracts of Acacia nilotica and Ziziphus spina-christi showed potent inhibitory activity against pancreatic lipase enzyme. Some of the extracts also showed significant genotoxicity and cytotoxicity at the concentration range used for bioactivities. The extracts of Acacia nilotica, Ziziphus spina-christi, Geigeria alata, Martynia annua and Abrus precatorius exhibited an appreciable range of activity on antioxidant and enzyme inhibitory assays.

25 November 2020 in Molecules
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Doaa AlsaadiDoaa Alsaadi
Doaa Alsaadi
Raju AedlaRaju Aedla
Raju Aedla
KKKen Kusakari
Ken Kusakari
FKFARUK KARAHAN
FARUK KARAHAN
Nazim SekerogluNazim Sekeroglu
Nazim Sekeroglu
TAKASHI WATANABETAKASHI WATANABE
TAKASHI WATANABE
The growth and quality of licorice depend on various environmental factors, including the local climate and soil properties; therefore, its cultivation is often unsuccessful. The current study investigated the key factors that affect the contents of bioactive compounds of Glycyrrhiza glabra L. root and estimated suitable growth zones from collection sites in the Hatay region of Turkey. The contents of three bioactive compounds (glycyrrhizic acid, glabridin, and liquiritin), soil factors (pH, soil bearing capacity, and moisture content), and geographical information (slope, aspect, curvature, elevation, and hillshade) were measured. Meteorological data (temperature and precipitation) were also obtained. An analysis of variance (ANOVA) and multivariate analysis of variance (MANOVA) were performed on the data. The soil bearing capacity, moisture content, slope, aspect, curvature, and elevation of the study area showed statistically significant effects on the glycyrrhizic acid and liquiritin contents. A habitat suitability zone map was generated using a GIS-based frequency ratio (FR) model with spatial correlations to the soil, topographical, and meteorological data. The final map categorized the study area into four zones: very high (15.14%), high (31.50%), moderate (40.25%), and low suitability (13.11%). High suitability zones are recommended for further investigation and future cultivation of G. glabra.

25 October 2019 in Molecules
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WSWataru Shida
Wataru Shida
HTHiroshi Tateishi
Hiroshi Tateishi
YTYurika Tahara
Yurika Tahara
Mikako FujitaMikako Fujita
Mikako Fujita
Doaa AlsaadiDoaa Alsaadi
Doaa Alsaadi
TAKASHI WATANABETAKASHI WATANABE
TAKASHI WATANABE
Despite the development of a range of anti-cancer agents, cancer diagnoses are still increasing in number, remaining a leading cause of death. Anticancer drug treatment is particularly important for leukemia. We screened Turkish plants and found the unique antileukemic activity of twig components in Turkish Caucasian beech, selectively inducing apoptosis in leukemia cells. This effect is unique among some kinds of beeches, presumably related to oxidative stress. This study would lead to effective use of discarded material, i.e., twig of beech, and a new anti-leukemic drug based on large tree.

22 November 2019 in Medicines
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AIAmina Ibrahim Ahmed Ibrahim
Amina Ibrahim Ahmed Ibrahim
MWMikiyo Wada
Mikiyo Wada
TAKASHI WATANABETAKASHI WATANABE
TAKASHI WATANABE
Hari Prasad DevkotaHari Prasad Devkota
Hari Prasad Devkota
Background: Blepharis linariifolia Pers. (Family: Acanthaceae) is used in traditional medicines as a general tonic and for the treatment of various health problems in Sudan. The main aim of this study was to isolate and identify the major chemical constituents from the aerial parts of B. linariifolia and evaluate their bioactivities. Methods: The dried aerial parts of the plant were extracted successively with 100% acetone and 50% acetone, and thereafter the combined extract was subjected to repeated column chromatography to isolate the main components. Free radical scavenging activity was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical method, and in vitro enzyme inhibitory activities against α-glucosidase, pancreatic lipase, and mushroom tyrosinase were evaluated. Results: From the detailed chemical analysis, verbascoside (1), vanillic acid (2), apigenin (3), and 6″-O-p-coumaroylprunin (4), were isolated and their structures were identified on the basis of their nuclear magnetic resonance (NMR) spectral data. Among the isolated compounds, verbascoside (1) showed the most potent free radical scavenging activity (IC50 = 22.03 ± 0.04 μM). Apigenin (3) and 6″-O-p-coumaroylprunin (4) showed promising inhibitory activities against all tested enzymes. Apigenin (3) showed the most potent inhibitory activity against α-glucosidase and tyrosinase (IC50 = 34.73 ± 1.78 μM and 23.14 ± 1.83 μM, respectively), whereas 6″-O-p-coumaroylprunin (4) showed potent inhibition for lipase (IC50 = 2.25 ± 0.17 μM). Conclusions: Four phenolic compounds were isolated and identified from B. linariifolia acetone extract, which are reported for the first time from this plant. All compounds showed good DPPH free radical scavenging activities, with verbascoside (1) being the most potent. Apigenin (3) was the most active as α-glucosidase and mushroom tyrosinase inhibitor, while 6″-O-p-coumaroylprunin (4) showed potent inhibitory activity for pancreatic lipase.

20 February 2024 in Molecules
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RURei Uranishi
Rei Uranishi
Raju AedlaRaju Aedla
Raju Aedla
Doaa AlsaadiDoaa Alsaadi
Doaa Alsaadi
DWDongxing Wang
Dongxing Wang
KKKen Kusakari
Ken Kusakari
TAKASHI WATANABETAKASHI WATANABE
TAKASHI WATANABE
The leaves of Chrysanthemum indicum L. are known to have various bioactive compounds; however, industrial use is extremely limited. To overcome this situation by producing high-quality leaves with high bioactive content, this study examined the environmental factors affecting the phytochemical content and antioxidant activity using C. indicum leaves collected from 22 sites in Kochi Prefecture, Japan. Total phenolic and flavonoid content in the dry leaves ranged between 15.0 and 64.1 (mg gallic acid g−1) and 2.3 and 11.4 (mg quercetin g−1), while the antioxidant activity (EC50) of the 50% ethanol extracts ranged between 28.0 and 123.2 (µg mL−1) in 1,1-Diphenyl-2-picrylhydrazyl radical scavenging assay. Among the identified compounds, chlorogenic acid and 1,5-dicaffeoylquinic acid were the main constituents in C. indicum leaves. The antioxidant activity demonstrated a positive correlation with 1,5-dicaffeoylquinic acid (R2 = 0.62) and 3,5-dicaffeoylquinic acid (R2 = 0.77). The content of chlorogenic acid and dicaffeoylquinic acid isomers varied significantly according to the effects of exchangeable magnesium, cation exchange capacity, annual temperature, and precipitation, based on analysis of variance. The habitat suitability map using the geographical information system and the MaxEnt model predicted very high and high regions, comprising 3.2% and 10.1% of the total area, respectively. These findings could be used in future cultivation to produce high-quality leaves of C. indicum.

7 February 2021 in Plants
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KHKengo Hori
Kengo Hori
TAKASHI WATANABETAKASHI WATANABE
TAKASHI WATANABE
Hari Prasad DevkotaHari Prasad Devkota
Hari Prasad Devkota
Cardiocrinum cordatum (Thunb.) Makino (Family: Liliaceae), commonly known as ‘Ubayuri’, is native to Japan and some islands in the Russian Far East. It has high value as food, medicinal, and ornamental species. The aim of this study was to isolate and characterize the main chemical constituents of the leaves of C. cordatum. A total of 19 compounds, namely caffeic acid (1), caffeic acid methyl ester (2), caffeic acid β-glucopyranosyl ester (3), caffeic acid 4-O-β-glucopyranoside (4), ferulic acid (5), isoferulic acid (6), protocatechuic acid (7), syringic acid (8), 2,6-dimethoxy-p-hydroquinone 1-O-β-glucopyranoside (9), esculetin (10), taxifolin (11), quercetin 3-O-(6-O-α-rhamnopyranosyl)β-glucopyranoside-7-O-β-rhamnopyranoside (12), 2,7-dimethyl-2,4-diene-deca-α,ω-diacid β-glucopyranoside (13), 4-[formyl-5-(methoxymethyl)-1H-pyrrol-1-yl]butanoic acid (14), (3Z)-3-hexenyl β-glucopyranoside (15), tryptophan (16), adenine (17), adenosine (18), and 2-deoxyadenosine (19) were isolated using various chromatographic methods. The structures of isolated compounds were elucidated on the basis of their NMR spectroscopic data. All these compounds were isolated for the first time from the genus Cardiocrinum. Phenolic acid derivatives and flavonoids can be considered as chemotaxonomic markers in the leaves of Cardiocrinum species.