K I E M SOAT GLUCOSE MAU SAU AN T R E N CHUOT
^DAI THAO DU'DNG VA TREN N G I / d l UONG NU VOI K H O E MANH
Truong Tuyet Mai', Asano Eri-, Le Thi Hffp\ Nguyen Thi Ldm\
Nguyen Vdn Chuyen^
Sang lpc tren 28 loai thirc vat an dugc d Viet Nam da tim thay nu Voi co ham lugng polyphenol cao va c6 kha nang ire che men alpha-glucosidase. Thii nghiem ve kha nang han che tang Glucose mau sau an ciia nu Voi tren chuot nhat khoe manh va'tren chuot Wistar dai thao duong cho thay, lugng Glucose mau ciia nhom chuot dugc uong bgt nu Voi (500mg/kg trpng lucmg CO the) giam mot each co y nghia so vdi nhom chuot doi chung, va hieu qua nay cao ban nhom chuot la Oi (500 mg/kg), va dat hieu qua gan giong nhom uong thuoc Acarbose (25 mg/kg). Tiep theo, trong mot thir nghiem dai ngay (8 tuan) ve hieu qua giam dudng huyet ciia nu Voi tren chuot dai thao dirdng cho thay, lirgng Glucose mau cila nhom chuot dai thao dirdng dugc udng 500 mg nu V6i/kg/ngay khong tang len va e6 xu hudng giam dan mot each dang ke so vdi nhdm chuot dai thao dudng doi chirng. Thu nghiem ve kha nang han che tang Glucose mau sau an ciia nu Voi tren 12 ngudi khde manh cho thay, lugng Glucose mau sau an tang it hon mot each cd y nghla d ngay uong nu Voi (200 ml tra nu Voi chiet tir 11.5 g nu Voi kho) so vdi ngay uong nude sdi.
Nu Voi la mot nguyen lieu diing de uong tir rat lau ddi, va dugc coi la an toan khi sir dung. Ngoai kha nang chong oxy hoa, nu Voi con co tae dung ban che tang Glucose mau sau an. Chinh vi vay, nu Voi CO the dirge xem la nguyen lieu tiem nang trong viec ho trg phong tri benh dai thao dudng.
Til khoa: Chudt ddi thdo du(7ng: ni vol
DAT VAN DE
BSnh dai thao dudng la mdt benh man tinh khong lay nguy hiSm vdi trieu chu-ng dudng mau cao, ty IS mac benh dang gia tang d cac nudc da va dang phat triSn. Do dd, can thiSt tim ra cac bien phap de quan ly can benh nay. Myc tiSu chinh Clia ragi giai phap cho benh nhan dai thao dudng la phai kiSm soat, duy tri ndng do dudng mau d mirc binh thudng, trong do CO viec han chS tang Glucose mau sau an [1]. Mdt sd thudc irc chS hoat ddng men
' Ts, BS - Vien Dinh du6iig i - Trudng DH Phu nu Nhat Ban
"* PGS, TS - Vien Dinh duong
"* GS, TS, Truo-ng DH Phii nCv Nhat Ban
thiiy phan dudng a-glucosidase nhu acar- bose va raiglitol da dugc sir- dung nham ban chS tang dudng huySt sau an [2].
Cac nha khoa hgc hien nay dang quan tam nghiSn ciai cac cay thudc cd kha nang hd trg phdng trj benh dai thao dudng. Da c6 han 400 loai cay co dugc xac djnh la cd tiSm nang giam dudng huySt trong mau. Mdt sd cd kha nang ire che men thiiy phan dudng trong ruot, nhu la Oi [3], qua Eugenia jamholana fruits [4], la ehe xanh [5]. Thanh phan polyphe-
nols trong thyc vat dugc xem la thanh phan ddng vai trd quan trgng trong ca chS kiSm soat boat dgng cac men thuy phan dudng trong rudt [6], [7]. Trong nghiSn cthi sang lgc tii- 28 loai thyc vat an dugc ciia Viet Nam, chimg tdi da tim thay nu Voi (Cleistocalyx operculatus (Roxh.) Merr and Perry ),c6 ham lugng polyphenol cao va cd hoat tinh ire chS men a-glucosidase [8].
Chinh vi vay, chiing toi tiSn hanh nghiSn cim ve kha nang kiSm soat Glucose mau sau an cua ny Voi trSn ddng vat va trSn ngudi.
II. NGUYEN LIEU VA PHUONG PHAP 2.1. Nguyen lieu vd phuffng phdp chiet tdch
Ny Vdi va la Oi dugc thu mua tai Viet Nara. Sau khi thu mua, nguySn lieu dugc chgn lgc, nia sach, lam ddng khd, sau dd dugc xay nhd thanh bdt. Chiet tach theo ty IS 100 g nu Vdi vdi 2 lit nudc, dat trong thiing nudc 100 °C trong 40 phiit.
Sau dd, dung phuang phap ly tara de thu lay dung djch chiSt tach. Lam ddng khd dung djch chiSt tach dS thu dugc bdt ny Vdi. ChiSt tach tuong ty vdi la 6i. Bdt nu Voi va bdt la 6 i dugc cat giii d tu da -80
"C va sir dyng trong vdng 3 thang. Thudc Acarbose va dudng maltose dugc mua tai cdng ty Wako Pure Chemical Industries, Osaka, Nhat Ban.
2.2. Thir nghiem khd ndng hgn che tdng duirng huyet sau dn cua nu Vdi tren chuot khde mgnh ICR vd chuot ddi thdo duffng Wistar
Sir dyng 24 con chudt khde manh ICR chia 4 nhom, moi nhdm 6 con, nhdm ddi chimg (udng nudc trang); nhdm Acabose (hSu lugng 25 mg/kg thS trgng);
nhdm la 6 i (liSu lugng 500 rag bgt la 6i/kg thS trgng); va nhdra nu Vdi (lieu lugng 500 mg bdt nu Vdi/kg thS trgng).
Chudt ddi qua dSni (14 gid), lay mau trudc khi cho udng cac nguySn lieu. Sau
khi cho cac nhdm chudt udng nguySn lieu noi trSn, 30 phut sau cho udng dudng maltose (2 g/kg thS trgng). Sau 30 phiit, 60 phiit va 120 phiit udng dudng maltose, lay mau ven dudi chudt thir nghiem dudng huySt bing kit glucose.
Tuang ty vdi chudt dai thao dudng Wistar dugc gay dai thao dudng bang thudc streptozotoein (STZ; 50 rag/kg the trgng). 24 chudt dai thao dudng (chia 4 nhdm moi nhdm 6 con) dugc xac djnh dudng huySt liic ddi va tiSn hanh thir nghiSm kha nang ban chS tang dudng huySt gidng nhu chugt khde manh ICR.
2.3. Thu nghiem ve khd ndng kiem sodt dudng huyet tren chuot ddi thdo dudng trong vdng 8 tudn udng nu Vdi
Hai muai bdn con chudt Wistar chia thanh 4 nhdm, nhdm chudt khde raanh doi chiing, nhdm chudt khde manh udng nu Vdi, nhdm chudt dai thao dudng chimg va nhdm chudt dai thao dudng udng ny voi.
Chudt dai thao dudng dugc gay dai thao dudng bang thudc streptozotoein vdi lieu 50 mg/kg the trgng. Chudt thyc nghiSm dugc nudi bang thirc an, nudc udng tieu chuan dat trong phdng nudi ddng vat.
Nhdm chudt can thiep dugc udng nu Voi vdi lieu lugng 500 mg bdt ny Vdi chiet tach/kg can nang/ngay, trong khi do nhdm chirng chi dugc udng nudc binh thudng.
Lay mau ven djnh ky, sau 2, 4, 6 va 8 tuan udng ny Vdi dS xet nghiem chi sd dudng huyet liic ddi.
2.4. Thie nghiem ve khd ndng hgn che tdng duffng huyet sau dn cua nu Voi tren ngudi khde mgnh
Mudi hai sinh viSn nir, khde manh, tudi hi 21-32 (trung binh 23.5 ± 3.0) vdi BMI trung binh 19.4 ± 1.4 kg/m', dudng mau luc ddi trung binh 94.5 ± 11.4 mg/dL dugc tham gia thu nghiSm tai Labo Hoa sinh Dinh dudng - Trudng Dai hgc Phu nir Nhat Ban. Cac ddi Urgng cam kSt tham gia, va dS cuong nghiSn ciru dugc Hoi
ddng Dao due con ngudi ciia Trudng Dai hge Phu nir Nhat Ban thdng qua.
Tra nu Vdi dugc chuan bj theo ty IS 35 g nu Vdi khd xay/1000 ml nudc, dun sdi trong 30 phut dS thu lay 600 mL tra ny Vdi. Biia an chuAn bj bao gdm 160 g cam gao te kem theo 2 gram ea thu bdt man (250 Kcal, 45 g carbohydrate, 4.5 g protein, 0.5 g lipid va 0.7 g chat xa).
TiSn hanh thir nghiSm vao 2 ngay khac nhau trSn ciing 12 ddi tugng. Ddi tugng dugc ySu cau dS byng doi qua dSm.
Ngay thii- nhat, cac ddi tugng chi udng 200 mL nudc trang, ngay thii- 2 udng 200 mL ny Vdi. Ngay sau khi udng, cac ddi tugng an cam trong thdi gian trung binh la 20 phut. Lay mau dau ngdn tay bang dyng cy Accu-Chek tai thdi diSm trudc khi udng, sau khi an com 30, 60 va 120 phut. Do dudng huyet bang dyng cu Accu-chek Active (cdng ty Wako, Nhat Ban). Tinh toan dudng cong AUC, phan tich y nghia thdng kS dimg Student's t test.
2.5. Phdn tich sd lieu
KSt qua trSn thi nghiem ddng vat dugc diSn ta theo means ± standard deviation (SD), vdi n=6. Sy khac biet giira 3 nhdm dugc phan tich bang ANOVA theo Dun- can's multiple-range t-test. Vdi gia trj p <
0.05 thi dugc xem la sy khac biet cd y nghTa thdng kS.
K E T Q U A
3.1. Khd ndng hgn che dudng huyet sau dn cua nu Voi tren chuot khde mgnh ICR vd chuot ddi thdo duffng Wistar
Hinh 1A va IB cho thay kha nang ban chS dudng huyet sau an cua nu Vdi trSn chudt khde manh ICR va chudt dai thao dudng. Ndng do dudng huyet cua nhdm chudt udng ny Vdi thap ban mdt each cd y nghia thdng ke so vdi nhdm chung sau 30 phiit d ca 2 thir nghiem.
Ndng do dudng huySt cua nhdm ny Vdi thap ban so vdi nhdm udng la Oi, va cao ban mdt chut so vdi nhdm udng Acarbose sau 30 phiit d thi nghiem chugt khde manh va sau 60 phut d thi nghiem chudt dai thao dudng.
£0 90 120
Thoi gian (min)
60 90 120
Thoi gian (min)
Hinh 1. Kha nang han che du-ffng huyet sau an cua nu V6i tren chuot khoe manh ICR (A) va chuot dai thao ducrng Wistar (B)
Control: nhom doi chirng: COB: nhom uong nu Vol: GUL: nhom uong Id Oi: Acarbose: nhom uong thudc Aearho.se. Ky tu a tuang icng vdi p <0.()5 so vai nhom chirng; ky tu h tuang img vdi p< 0.01 so v&i nhom chiinv.
3.2. Khd niing kiem sodt duffng huyet tren chudt ddi thdo dud'ng trong vdng 8 tudn udng nu Vdi
Bang 1 cho thay, ndng do dudng huyet ciia nhdm chugt dai thao dudng uong nu Vdi khdng tang ISn, giam dan
mdt each cd y ngliTa so vdi nhdm chudt dai thao dudng ddi chii-ng sau 2, 4, 6 va 8 tuan. Trong khi dd, ndng do dudng huySt d nhdm chudt khde manh udng nu Voi trong 8 tuan khdng thay ddi so vdi nhom chudt klide manh ddi chung
Bang I. Kha nang kiem soat duong huyet tren chuot dai thao duong trong vong 8 tuan uong nu V6i
Nhom Trudc CT Sau 2 tuan Sau 4 tuan Sau 6 tuan Sau 8 tuan
Chuot khoe 14.7+ 15.5" 119.0+ 12. 120.8+ 10.4 a I8.0+ 13.7'' 17.5 ± 12.3'' Chuot khoe + V6i 116.7+18.2^ 114.0+10.2'' 114.4 + 8.1^ 113.0+10.9'^ 113.5±8.3'' Chuot DTD • 268.5 +23.4b 273.8 ± 2 3 . l b 277.3 ± 22.4b 283.9 ± 20.2b 283.7 i 22.7b Chuot DTD + V6i 271.6+ 18.9b 240.1 +25.6^^,* 216.9 ± 32.5*^,** 217.1 ±27.2'^,** 211.3 + 20.4'^,***
Cdc gid iri hieu dien bang Mean ± SEM (n= 6). Tren cimg iiidl cot. .^ir khde hicl giiia cdc gid trj trung hinh hdng cdc chir liy lulilidc nhau (p <0.05). Voi *p <0.05: **p <O.OI: *** < 0.001 hieu dien .sir khde biet cua gid Iri trung binh tcii cdc thai diem .so viri gid tri truac can thiep trong < iing nhdm (I')unean '.s multiple-range l-le.sl).
3.3. Khd ndng hgn che tdng duirng huyet sau dn cua nu Vdi tren ngudi khde mgnh
Hinh 2 va bang 2 cho thay tai thdi diSm ban dau, ndng do dudng huySt khong khac biet giiia 2 ngay thu nghiSm.
Trong ngay ddi chimg (ngay udng nudc), sau khi an com, ndng do dudng huySt tang dan tir 94.5 mg/dL tdi 142.0, 117.2, va 105.7 mg/dL, trong khi do, ndng do dudng huySt cua ngay udng nu Vdi tang it hon, tir 92.9 mg/dL tdi 120.0, 106.8, va
100.5 mg/dL sau 0, 30, 60 va 120 phut an cam. Viee tang dudng huySt Sau an 30 phut, ndng do dudng huySt d ngay uong nu Vdi thap hon mot each dang kS so vdi ngay doi chimg. Sy khac biet co y nghla thdng kS vS chi sd dudng cong dudi AUC dugc tim thay giiia dudng huySt ngay doi chung va ngay udng ny Vdi. Gia trj AUC ciia ngay ddi chimg la 237.0 ± 25.7, trong khi ngay udng nu Vdi la 213.5 ± 21.1
(p<0.05).
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Hinh 2. Kha nang han ch6 tang duong huy^t sau an cua nu Vol tren nguoi khoe manh (n=I2)
Bang 2. Glucose mau sau an (mg/dl.) va miic do tang duwng huyet (mg/dL) va chi s6 AUC (mg/dL/giff) sau bira an va khong u6ng nu Voi
Thoi diem Thoi diem truac khi Sau 30 phut
Sau 60 phiu
Sau 120 phiit
0-120 phiit
Chi so
an Dircrng huyet liic doi DiriVng huyet
Mirc tang duang huyet Duong huyet
Mirc tang duang huyet Duang huyet
Mirc tang duang huyet Chisd AUC
Ngay uong nu-oc trang 94.5+ 11.4
141.9 + 22.6 48.6 + 22.8
117.2+ 16.1 24.5 + 20.6 105.7+ 10.6 10.8 + 9.6 237.0 + 25.7
Ngay uong nu 92.9 + 9.4
120.0 ± 18.0 27. i ± 12.4*
106.8+ 12.8 13.8 + 8.1 100.5 + 8.6 7.6 + 8.8 213.5 + 21.0
Voi p
0.71 0.01 0.01 0.09 0.12 0.64 0.46 0.02 p < 0.05: sir khiic biet cd y nghia thdng ke ve chi .'id duang huyet giira uong nu Vdi vd udng ntrdc trdng: '^Sir khde biet cdy ngliia thdng ki; ve mice tdng dudng hiiyel giira ngdy udng nu Vdi vd ngdy khdng udng nu Vdi.
IV. BAN LUAN
Tir nghiSn cim sang Igc trSn 28 loai thyc vat an dugc ciia Viet Nam, chiing tdi tim thay nu Vdi cd kha nang uc chS men thiiy phan dudng, alpha-glucosidase.
Trong thir nghiSm tren chudt khde manh va chudt dai thao dudng, nu Voi dugc chirng minh kha nang ban chS tang dudng huySt sau an liSu 500 mg/kg the trgng.
Viec tinh toan liSu lugng, chirng tdi dya vao mdt sd nghiSn ciiu trudc, Deguchi va cong sy (1998) sir dung 500 mg bdt la Oi/kg thS trgng ciia chudt trong thir nghiSra kha nang ban ehe tang dudng huySt sau an ciia la Oi [3]. Trong nghien ciru nay, chiing tdi sii- dung la 6 i (500 mg/kg thS trgng) va thudc Acarbose (25 rag/kg thS trgng-theo liSu lugng diSu trj) la nguySn lieu chiing duong tinh dS so sanh vS kha nang han ehe tang dudng huyet sau an vdi nu Vdi. Theo nghiSn eiru trudc cua Deguchi va cimg .vir (1998), la 6 i cd kha nang irc chS hoat ddng men tiSu hda dudng nhu alpha-glucosidase. La 6 i
ciing da dugc thir nghiSm trSn chudt va tren ngudi khde manh dS chiing minh kha nang han chS dudng huy St sau an.
Kha nang lie chS men tiSu hda dudng cua mdt sd polyphenols trong mdt sd loai thyc vat ciing da dugc cac nha khoa hgc chirng minh. Theo nghiSn cim cua Hara and Honda, 1990 [5], polyphenols cua la che xanh cd kha nang irc chS men a-amy- lase. Polyphenols chiSt xuat cua bap cai dd (red cabbage), qua dau tay (strawberries), qua dau nhd (raspberries) ciing cd kha nang irc chS men a-amylase va a-glucosidase [6]. NghiSn ciru trudc cua chiing tdi ciing da chi ra nu Vdi cd hara lugng polyphenol cao va cd kha nang irc chS boat dgng men alpha-glucosidase.
Ham lugng polyphenols cua la Oi va ny Vdi la gan tuong duong nhau, ia 6 i la
122,5 mg va ny Vdi la 122,8 mg cate- chin/grara trgng lugng khd [8]. Nhung kha nang ire chS men alpha-glucosidase va hieu qua han chS tang dudng huySt sau an trSn chudt ciia nu Vdi lai cao ban so
vdi la 6 i [9]. KSt qua thir nghiera dng nghiSm va trSn chugt ciing da chi ra ny Voi cd tiem nang hd trg phdng trj benh dai thao dudng thdng qua kha nang han chS tang dudng huy St sau an ciia ny Vdi.
Tir cac kSt qua thir nghiem, chung tdi hSn hanh cho chudt khde manh va chudt dai thao dudng udng ny Vdi hang ngay trong 8 tuan liSn tyc vdi liSu lugng 500 mg/kg the trgng. KSt qua cho thay, ny Vdi cd kha nang kiSm soat dudng huySt trSn chugt dai thao dudng, dudng huySt ciia nhdm chugt dai thao dudng udng ny Vdi hang ngay cd xu hudng giam xudng va dn djnh, trong khi nhdm chudt dai thao dudng ddi chirng (chi udng nudc binh thudng) thi dudng huySt tang dan. Tac gia Yadav vd cong 5M- [ 10] da nghiSn cim vS hieu qua kiem soat dudng huySt cua la cay Murraya koenigii vdi liSu lugng khac nhau, tir 200- 700 mg bgt Murraya koenigii /kg thS trgng/ngay, kSt qua cho thay, liSu 500 mg/kg thS trgng thi hieu qua lai dat cao nhat va dn djnh. Trong nghien cuu cua chiing tdi, nhdm chudt khde manh dugc udng 500 mg/kg the frgng/ngay, da khdng xuat hien bat cir mdt trieu chirng bat thudng nao trong suot 8 tuan udng nu Vdi. Ket qua dudng huy St cua nhdm chugt khde raanh udng nu Vdi hau nhu khdng thay ddi so vdi nhdm chudt khde manh ddi chimg. BSng chirng nay bd sung thSra vao tinh an toan cua ny Vdi ma dan gian da su dyng ny Vdi tir rat lau, ny Vdi cd tac dyng vdi tinh trang dudng huySt cao, ma khdng anh hudng dudng huySt cua tinh trang dudng huySt binh thudng.
Cac bang chting thu dugc tir dng nghiem va trSn ddng vat, chiing tdi tiSn hanh thir nghiem trSn ngudi khoe manh vS kha nang han chS tang dudng huyet sau an ciia ny Vdi. Dudng huySt trung binh
ciia ngay udng ny Vdi (200 ml tra nu Voi chiSt hr 11.5 g nu Voi khd) duge giam di so vdi ngay udng nudc trang, diSu do chimg td ring ny Vdi cd kha nang ban chS dudng hap thu vao mau ma ca chS cd thS do ny Vdi irc che boat ddng ciia men tiSu hda dudng. Cac nghiSn ciru vS hieu qua kiSm soat dudng huySt ciia nu Vdi tren benh nhan dai thao dudng trong thdi gian dai se dugc tiSn hanh trong thdi gian tdi.
KET LUAN
Cac kSt qua cua nghiSn cim cho thay ny Vdi cd kha nang ban chS tang dudng huyet sau an trSn chugt khde manh va chudt dai thao dudng. Ddng thdi, ny Voi cd kha nang kiSm soat dudng huySt lau dai trSn chudt dai thao dudng. Ben canh dd, kha nang ban chS tang dudng huyet sau an trSn ngudi khde manh ciia ny Voi ciing da dugc chung minh.
Chinh vi vay, ny Vdi cd thS dugc coi la mdt nguySn lieu tiSm nang trong viec hd trg phdng trj benh dai thao dudng.
TAI LIEU THAM KHAO
1. van de Laar, F. A., Lucassen, P. L., Akkermans, R. P., van de Lisdonk, E. H., Rutten, G. E., and van Weel, C. (2005).
A Ipha-glucosidase inhibitors for patients 'with type 2 diabetes: results from a Cochrane systematic revie'w and meta- analysis. Diabetes Care, 28, 154-163.
2. Lefebvre, R J., and Schcen, A. J. (1994).
The use of acarbose in the prevention and treatment of hypoglycaemia. Eur J.
Clin. Invest., 24, 40-44.
3. Deguchi, Y., Osada, K., Uchida, K., Ki- mura, H., Yoshikawa, M., Kudo, T., Yasui, H., and Watanuki, M. (1998). Ef fects of extract of guava leaves on the
development of diabetes in the dh/db mouse and on the postprandial blood glucose of human. Nippon Nogeikagaku Kaishi (in Japanese), 72, 923-931.
52
4. Grover, J. K., Vats, V, and Rathi, S. S.
(2000). Anti-hyperglycemic effect of Eu- genia jamholana and TInospora cordifo- , lia in experimental diabetes and their
effects on key metabolic enzymes in- volved in carbohydrate metabolism. J.
Ethnopharmacol., 73, 461 -470.
5. Hara, Y , and Honda, M. (1990). The in- hibition of alpha-amylase by tea polyphenols. Agric Biol Chem, 54:
1939-1945.
6. IVIcDougall GJ, Shapiro F, Dobson P, Smith ?, Blake A and Stewart D (2005).
Different polyphenolic components of soft fruits inhibited alpha-amylase and alpha-glucosidase. J Agric Food Chem, 53:2760-2766.
7. Tadera K, Minami Y, Takamatsu K and Matsuoka T (2006). Inhibition of alpha- glucosidase and alpha-amylase by
flavonolds. J Nutr Sci Vitaminol, 52(2):
149-153.
8. Traong Tuyet IVIai, Nghiem Nguyet Thu, Pham Gia Tien and Nguyen Van Chuyen. (2007). Alpha-glucosidase In- hibititory and Antioxidant Activities of
Vietnamese Edible Plants and their Rela- tionships with Polyphenol Contents. J Nun Sci Vitaminol 53, 267-276.
9. Truong Tuyet Mai and Nguyen Van Chuyen (2007). Anti-hyperglycemic ac- tivity of an aqueous extract from flower buds of Cleistocalyx operculatus (Roxb.) Merr and Perry. Biosci Biotechnol Biochem 71(1), 69-76.
10. Yadav, S., Vats, V , Dhunnoo, Y , and Grover, J. K. (2002). Hypoglycemic and antihyperglycemic activity of Murraya koenigii leaves in diabetic rats. J.
Ethnopharmacol., 82, 111-116.
Summary
THE REDUCING IN THE POSTPRANDIAL OF FLOWER BUDS OF CLEISTOCALYS OP- ERCULATUS (ROXB) MERR AIVD PERRY IN DIABETIC RAT AND HEALTHY HUMAN A screening of 28 plants used for making drinks in Vietnam revealed a Cleistocalyx operculatus (Roxh.) Merr and Perry flower bud extract to have the high polyphenol content and the highest in- hibitory activity against the a-glucosidase enzyme. The anti-hyperglycemic effects of an aqueous extract from flower buds of Cleistocalyx operculatus (COB) were therefore investigated in the animal and the healthy human subjects. Postprandial blood glucose tesdng of normal mice and STZ-induced diabedc rats by maltose loading (2 g/kg body weight (bw)) showed that the blood glu- cose reduction with COB (500 mg/kg bw) was slightly less than that with acarbose (25 mg/kg bw) but was more potent than that with Guava leaves (500 mg/kg bw). In an 8-week experiment, the blood glucose level of STZ diabetic rats treated with 500 mg of COB/kg bw/day was markedly de- creased in comparison with that of non-treated diabedc rats. In the testing of postprandial glycemia in healthy participants showed that the increment of postprandial glucose level in blood (IBG) was significantly suppressed on the Nu Voi day (200 ml) in comparison with that on the control day at 30 min after eadng the cooked rice of 160g. Therefore, COB tea suppressed the increment of postprandial blood glucose and might be useful prevent in the development of diabetes.
Keywords: Diabetic rats: flower buds of cleirtocalyx operculatus