Emi Okuyama

Bio: Emi Okuyama is an academic researcher from Chiba University. The author has contributed to research in topics: Monoamine oxidase & Anisatin. The author has an hindex of 28, co-authored 73 publications receiving 2250 citations. Previous affiliations of Emi Okuyama include Khon Kaen University.

Separation of Leucas aspera, a medicinal plant of Bangladesh, guided by prostaglandin inhibitory and antioxidant activities.

Abstract: According to the traditional usage of the plant for antiinflammation and analgesia, Leucas aspera was tested for its prostaglandin (PG) inhibitory and antioxidant activities. The extract showed both activities, i.e., inhibition at 3 x 10(-4) g/ml against PGE(1)- and PGE(2)-induced contractions in guinea pig ileum and a 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging effect. The separation guided by the activities in these dual assay methods provided eight lignans and four flavonoids, LA-1- -12, among which LA-1- -7 and LA-10- -12 were identified as nectandrin B, meso-dihydroguaiaretic acid, macelignan, acacetin, apigenin 7-O-[6"-O-(p-coumaroyl)-beta-D-glucoside], chrysoeriol, apigenin, erythro-2-(4-allyl-2, 6-dimethoxyphenoxy)-1-(4-hydroxy-3-methoxyphenyl)propan-1-ol, myristargenol B, and machilin C, respectively. LA-8 was determined to be (-)-chicanine, the new antipode of the (+) compound, by spectroscopic methods including CD and ORD. Chiral-HPLC analysis of LA-9 showed that it was a mixture of two enantiomers, (7R, 8R)- and (7S, 8S)-licarin A. All of these components were first isolated from L. aspera. PG inhibition was observed in LA-1, LA-2, and LA-5, and antioxidant activity in LA-1- -3 and LA-8- -12.

Usnic acid and diffractaic acid as analgesic and antipyretic components of Usnea diffracta

Abstract: Diffractaic acid and usnic acid were identified as the analgesic and antipyretic components of a lichen, Usnea diffracta. Both compounds showed an analgesic effect by the acetic acid-induced writhing and tail-pressure methods in mice. Regarding the effect on normal body temperature and LPS-induced hyperthermia in mice, diffractaic acid showed a significant effect only on the former and usnic acid only on the latter.

Analgesic components of saposhnikovia root (Saposhnikovia divaricata).

Abstract: By activity-oriented separation using the writhing method in mice, the analgesic components of Saposhnikovia root (Saposhnikovia divaricata Schischkin; Umbelliferae) were identified to be chromones, coumarins, polyacetylenes and 1-acylglycerols. Two new components, divaricatol and (3'S)-hydroxydeltoin, were also isolated. The most potent analgesia was observed in chromones such as divaricatol, ledebouriellol and hamaudol, which inhibited writhing inhibition at an oral dose of 1 mg/kg in mice. Acylglycerols also showed inhibition significantly at a dose of 5 mg/kg. In some pharmacological tests using sec-O-glucosylhamaudol, the compound showed analgesia by the tail pressure and the Randall & Selitto methods, and its writhing inhibition was not reversed by naloxone.

Immunomodulatory constituents from an ascomycete, Microascus tardifaciens.

Abstract: Fractionation guided by the immunosuppressive activity of the defatted AcOEt extract of an Ascomycete, Microascus tardifaciens, afforded eight constituents, questin (emodin 8-O-methylether) (1), rubrocristin (2), 5, 7-dihydroxy-4-methylphthalide (3), cladosporin (asperentin) (4), cladosporin 8-O-methylether (5), tardioxopiperazine A [cyclo-L-alanyl-5-isopentenyl-2-(1', 1'-dimethylallyl)-L-tryptophan] (6), tardioxopiperazine B [cyclo-L-alanyl-7-isopentenyl-2-(1', 1'-dimethylallyl)-L-tryptophan] (7), and asperflavin (8), among which 6 and 7 were new compounds. Compounds 1 and 2 showed considerably high immunosuppressive activity, 6 was moderate and, 3, 4, 5, 7 and 8 showed low activity.

The combinatorial synthesis of bicyclic privileged structures or privileged substructures

Abstract: Privileged substructures are of potentially great importance in medicinal chemistry. These scaffolds are characterized by their ability to promiscuously bind to a multitude of receptors through a variety of favorable characteristics. This may include presentation of their substituents in a spatially defined manner and perhaps also the ability to directly bind to the receptor itself, as well as exhibiting promising characteristics to aid bioavailability of the overall molecule. It is believed that some privileged substructures achieve this through the mimicry of common protein surface elements that are responsible for binding, such as β- and gamma;-turns. As a result, these structures represent a promising means by which new lead compounds may be identified.

Coronary artery calcium score combined with Framingham score for risk prediction in asymptomatic individuals

Abstract: ContextGuidelines advise that all adults undergo coronary heart disease (CHD) risk assessment to guide preventive treatment intensity. Although the Framingham Risk Score (FRS) is often recommended for this, it has been suggested that risk assessment may be improved by additional tests such as coronary artery calcium scoring (CACS).ObjectivesTo determine whether CACS assessment combined with FRS in asymptomatic adults provides prognostic information superior to either method alone and whether the combined approach can more accurately guide primary preventive strategies in patients with CHD risk factors.Design, Setting, and ParticipantsProspective observational population-based study, of 1461 asymptomatic adults with coronary risk factors. Participants with at least 1 coronary risk factor (>45 years) underwent computed tomography (CT) examination, were screened between 1990-1992, were contacted yearly for up to 8.5 years after CT scan, and were assessed for CHD. This analysis included 1312 participants with CACS results; excluded were 269 participants with diabetes and 14 participants with either missing data or had a coronary event before CACS was performed.Main Outcome MeasureNonfatal myocardial infarction (MI) or CHD death.ResultsDuring a median of 7.0 years of follow-up, 84 patients experienced MI or CHD death; 70 patients died of any cause. There were 291 (28%) participants with an FRS of more than 20% and 221 (21%) with a CACS of more than 300. Compared with an FRS of less than 10%, an FRS of more than 20% predicted the risk of MI or CHD death (hazard ratio [HR], 14.3; 95% confidence interval [CI]; 2.0-104; P = .009). Compared with a CACS of zero, a CACS of more than 300 was predictive (HR, 3.9; 95% CI, 2.1-7.3; P<.001). Across categories of FRS, CACS was predictive of risk among patients with an FRS higher than 10% (P<.001) but not with an FRS less than 10%.ConclusionThese data support the hypothesis that high CACS can modify predicted risk obtained from FRS alone, especially among patients in the intermediate-risk category in whom clinical decision making is most uncertain.

Distribution and biological activities of the flavonoid luteolin.

Abstract: Epidemiological evidence suggests that flavonoids may play an important role in the decreased risk of chronic diseases associated with a diet rich in plant-derived foods. Flavonoids are also common constituents of plants used in traditional medicine to treat a wide range of diseases. The purpose of this article is to summarize the distribution and biological activities of one of the most common flavonoids: luteolin. This flavonoid and its glycosides are widely distributed in the plant kingdom; they are present in many plant families and have been identified in Bryophyta, Pteridophyta, Pinophyta and Magnoliophyta. Dietary sources of luteolin include, for instance, carrots, peppers, celery, olive oil, peppermint, thyme, rosemary and oregano. Preclinical studies have shown that this flavone possesses a variety of pharmacological activities, including antioxidant, anti-inflammatory, antimicrobial and anticancer activities. The ability of luteolin to inhibit angiogenesis, to induce apoptosis, to prevent carcinogenesis in animal models, to reduce tumor growth in vivo and to sensitize tumor cells to the cytotoxic effects of some anticancer drugs suggests that this flavonoid has cancer chemopreventive and chemotherapeutic potential. Modulation of ROS levels, inhibition of topoisomerases I and II, reduction of NF-kappaB and AP-1 activity, stabilization of p53, and inhibition of PI3K, STAT3, IGF1R and HER2 are possible mechanisms involved in the biological activities of luteolin.