department of pharmacognosy...natural products are categorized as secondary metabolites, which...

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DIVISION OF PHARMACEUTICAL SCIENCES

We human beings have a long history of usingvarious natural resources as plants and animals forcuring disease and wounds. Natural medicinesselected among those trials have been handeddown to this century and still being used in our dailylife. Also numerous pharmaceutics have beendeveloped from compounds of natural productswhich were isolated from plants and microbes.However, natural medicines still include mysteries tobe uncovered and potentials for creation of anoth-er pharmaceutics. Our studies on these mysteriesand potentials are performed based on fieldworksand the following combination of lab-works.

1) Therapeutic use of incense and balm: “Kho-Doh”, an incense ceremony, is one of the most ele-gant and traditional culture of Japanese; a smallpiece of agarwood of the highest quality is heatedon a thin mica plate above charcoal, and a subtlefragrant arise from the piece is breathed in for tast-ing. Recent pharmacological studies indicate thatthe fragrant of agarwood might be a potent seda-tive, and which was experimentally exhibited usingour new assay system. Further analyses on theactive compounds and their mode of actions areunder performance in the lab. Fragrant naturalmedicines other than agarwood, such as patchouliand spikenard that are often found in ingredients ofJapanese sachet, are also analyzed for their poten-tials for therapeutic use.

2) Biosynthetic enzymes of secondary metabolismin medicinal plants: A large number of medicinalnatural products are categorized as secondarymetabolites, which differ from primary metabolitesand are unique to plants. Among these we arefocusing on fragrant volatiles which are mainlyfound in essential oi l and resin of plants.Biosynthetic pathways and enzymes committed tothem are studied through a combination of molec-ular biological techniques and conventional genet-ics. Agarwood, which was already mentioned in 1),

and perilla, a common Labiatae kitchen herb, arematerials of recent topics.

3) Fieldwork: In order to understand mechanismsand functions of secondary metabolism in plants, itis essential for researchers to know and experiencethe target with their own five senses, we suppose.Therefore, we perform field surveys (= fieldworks)and cultivate plant materials (= works) in our experi-mental station (= field); collecting experimentalmaterials is certainly an object of the fieldworks,however, new ideas might be generated as resultsof watching and touching the target in the field-works. An interview to old healer in village is a com-mon means for collecting information of folkmedicines, which sometimes seems unlikely to thepharmaceutical sciences; how one could makemutual understanding with interviewee would be akey for these interviews. Our recent f ield isIndochina (Viet Nam, Lao PDR, Thailand, etc.) forpursuing agarwood, perilla, and unknown folkmedicines.

4) Regulatory sciences on natural medicines(crude drugs): Medicinal plants and other naturalmaterials are used as Kampo medicines and ingre-dients of different natural medicines. Many ofthese are used not only as pharmaceuticals butalso as spices and materials for health foods; theyhave both natures of medicines and foods. A nat-ural medicine that has different names in differentcountries may make troubles when it is tradedinternationally; it may be used in a wrong way toevoke unexpected side effects. In order not tohappen the negative events in use of naturalmedicines, and to secure the safe use of naturalmedicines and their products, proper identificationmethods and other techniques and knowledgethat wil l be useful for regulation on naturalmedicines are required. These knowledge andtechniques are another tagets for our studies.

Recent publications●Naoko Sato-masumoto, Michiho Ito, Domain swapping approach to regiospecific hydroxylation by geran-

iol and linalool synthases from perilla. Phytochemistry, 102, 46-54 (2014).

●Hiroaki Takemoto, Michiho Ito, Yoshinori Kobayashi, Inhalation administration of valerena-4,7(11)-diene from

Nardostachys chinensis roots ameliorates restraint stress-induced changes in murine behavior and stress-

related factors. Biol. Pharm. Bull., 37 (4), (2014).

●Yukie Kumeta, Michiho Ito, Characterization of δ-guaiene synthases from cultured cells of Aquilaria, respon-

sible for the formation of the sesquiterpenes in agarwood. Plant Physiology, 154 (4) 1998-2007 (2010).

Department of PharmacognosyAssociate Professor: Michiho Ito

Research Projects: