KOREAN J. FOOD SCI. TECHNOL. Vol. 42, No. 5, pp. 598~604 (2010) The Korean Society of Food Science and Technology 국내산수수 (Sorghum bicolor) 품종에따른전자공여능, 환원력, 항균활성및 α-glucosidase 저해활성의비교 사여진 1 김주성 2 김명옥 1 정현주 1 유창연 1 박동식 3 김명조 1,2 * 1 강원대학교식물자원응용공학과, 2 강원대학교한방바이오연구소, 3 농촌진흥청국립농업과학원한식세계화연구단기능성식품과 Comparative Study of Electron Donating Ability, Reducing Power, Antimicrobial Activity and Inhibition of α-glucosidase by Sorghum bicolor Extracts Yeo-Jin Sa 1, Ju-sung Kim 2, Myeong-Ok Kim 1, Hyun-Ju Jeong 1, Chang-Yeon Yu 1, Dong-Sik Park 3, and Myong-Jo Kim 1,2 * 1 Department of Applied Plant Sciences, Kangwon National University 2 Oriental Bio-herb Research Institute, Kangwon National University 3 Funtional Food & Nutrition Division, Rural Development Administration Abstract Electron donating ability (EDA), reducing power, total phenolic contents, total flavonoid contents, antimicrobial activity, and α-glucosidase inhibitory effects of twenty-two sorghum varieties were examined using ethanol extracts (70%, v/v). The electron donationg abilities (EDA) of Mesusu and Bulgeunjangmoksusu (94% at 10 µg/ml) indicated higher antioxidant activity compared to those of other varieties and standard antioxidants such as BHT (13%) and BHA (74%). The reducing power of Mesusu (OD 700 =0.7 suggested higher antioxidant activity, which was dependent on sample concentration. Bitjarususu showed the highest content of total phenolics (22.9 mg GAE/g); however, extracts from Heuinsusu exhibited the lowest content of total phenolics (16.4 mg GAE/g). Jangmoksusu showed the highest total flavonolic contents (3.5 mg QE/g), and Sigyeongsusu and Chal (GS) susu displayed the most antibacterial activity (MIC=8 µg/ml) against Escherichia coli. Extracts of Bulgeunjangmoksusu, Moktaksusu, and Ginjangmoksusu showed the highest α-glucosidase inhibitory effect (98%) at the concentration of 5 µg/ml. Key words: α-glucosidase inhibitory effect, antimicrobial activity, electron donating ability, reducing power, total phenolic contents 서 수수 (Sorghum bicolor) 는외떡잎식물로벼목화본과에속하는한해살이풀로북아프리카와아시아에걸쳐서식용으로재배되고있다. 예로부터수수는가뭄방지작물이라고불릴정도로불리한환경에서잘자라는특징을가지고있으며, 세계에서밀, 벼, 보리, 옥수수다음으로수확량이많은작물로알려져있다. 민간요법에따르면수수의주성분은식욕개선, 소화촉진, 체온유지, 위장보호, 해독등여러가지작용을한다고알려져있다 (. 이와같이여러가지기능을가지고있는수수는고부가가치를높일수있는중요한곡류임에도불구하고조, 보리에비해품질 ( 찰기, 식미 ) 이떨어지기때문에다른곡류들에비해서이용이적은실정이며이를보완하기위해수수에대한연구가활발 *Corresponding author: Myong-Jo Kim, Department of Applied Plant Sciences, Kangwon National University, Chuncheon, Gangwon 200-701, Korea Tel 82-33-250-6413 Fax: 82-33-244-6410 E-mail: kimmjo@kangwon.ac.kr Received April 26, 2010; revised June 17, 2010; accepted June 28, 2010 론 히진행되고있다. 수수의주요성분들은 tannins, phenolic acids, antocyanins, phytosterols, policosanols 등으로 (2-4), 특히수수에많이함유되어있다고알려져있는 tannins 은항산화활성에영향을미치는것으로보고되어진바있다 (5). 또한수수는항암 (6), 항돌연변이 (7), 발암 promotion 억제효과 (8) 가보고되었으며, 다른곡류에서발견되지않은 3-deoayflavonoids 는강한항산화활성을나타내었다 (9). 그리고지장세포증식능과 cytokine 생성량을증가시켜면역기능을강화하며 (, 콜레스테롤을저하하여심장질환예방에효과가있다고보고되었다 (10). 이러한이유로최근에사람들이다양한목적으로수수를이용하고있다 (1. 미국에서는동물의사료제조와밀글루텐에알레르기가있는사람들의대체품으로이용되며, 아프리카에서는소화기관질병치료를위한죽으로만들어섭취하고있다. 또한, 우리나라뿐만아니라, 일본, 중국, 인도, 중남미에서는술, 과자, 떡, 엿등의다양한형태로수수를섭취하고있으며, 웰빙과기능성식품에대한관심이증대되면서간편한식사대용으로선식과생식으로도이용하고있다 (12,13). 본연구에서는수수 22 품종의생리활성을알아보고자항산화활성, 총페놀, 총플라보노이드함량, 항미생물활성및항당뇨활성등의생리활성을검정하여새로운기능성소재로서의가치를평가하는데기초자료를얻고자한다. 598
국내산수수 (Sorghum bicolor) 품종에따른전자공여능, 환원력, 항균활성및저해활성의비교 599 재료및방법 실험재료강원도원주시신림농협으로부터 2009 년 2 월경에토종수수 22 개품종을제공받아본실험에사용하였다. 추출물의제조시료 15 g 에 10 배의 70% ethanol 을넣고 1 시간동안, 24 시간간격으로 sonic bath(powersnic 420, Hwashin, Seoul, Korea) 을이용해 3 반복추출하였다. 각추출물을여과한후 rotary vacuum evaporator(ne-2001 & AC-1112A, Eyela Co., Tokyo, Japan) 로감압농축한후에동결건조하여 20 o C 에보관하면서실험에사용하였다. 총페놀및플라보노이드함량측정수수추출물의총페놀함량은 Taga 등에의해보고되어진 Folin-ciocalteau 방법 (14) 을사용하였다. 추출물 0.1 ml 에 Folin-ciocalteu reagent 0.05 ml, 20% sodium carbonate 0.3 ml 를가하였다. 15 분후증류수 1mL 를넣어혼합한후 UV-vis spectrophotometer(v-530, Jasco Co., Tokyo, Japan) 를이용하여 725 nm 에서흡광도를측정하였다. 페놀화합물함량은표준물질 gallic acid 를이용하여검량선을작성한다음정량하여 GAE(gallic acid equivalents) 로나타내었다. 총플라보노이드함량은 Moreno 등 (15) 의방법을변형하여측정하였다. 추출물 0.5 ml 에 10% aluminum nitrate 0.1 ml, 1 M potassium acetate 0.1 ml 그리고 80% ethanol 4.3 ml 를차례로가하여혼합하고실온에서 40 분간안정화시킨다음 415 nm 에서흡광도를측정하였다. Quercetin 을표준물질로이용하여검량선을작성한다음 quercetin equivalents(qe) 로나타내었다. 전자공여능 (electron donating ability, EDA) 수수추출물은 Blois 의방법 (16) 을변형하여측정하였다. 추출물 0.1 ml 에 methanol 4 ml, 0.15 mm 1,1-diphenyl-2-picrylhydrazyl(DPPH) 1 ml 를혼합하여실온에서 30 분간안정화시킨다음 517 nm 에서흡광도를측정하였다. Sample 첨가구와무첨가구의흡광도차이를백분율 (%) 로표시하여전자공여능을측정하였으며아래와같이계산하였다. EDA(%)=(1 absorbance value of sample/absorbance value of control) 100 환원력측정 Reducing power는 Oyaizu의방법 (17) 을변형하여측정하였다. 70% ethanol 추출물 (10 µg/ml) 30, 60, 90 µl에 0.2 M sodium phosphate buffer(ph 6.6) 500 µl, 1% potassium ferricyanide 500 µl를각각혼합하여 50 o C에서 20분동안반응시킨후 10% trichloroacetic acid 2.5 ml을가하였다. 위반응액을 650 rpm에서 10분간원심분리하여상층액 500 µl에증류수 500 µl, 1% ferric chloride 100 µl를가하여혼합한반응액의흡광도값을 700 nm 에서측정하였다. 항균실험그람양성균 Bacillus subtilis(kctc 102, Staphylocoocus aureus (KCTC 1916), 그람음성균 Klebsiella pneumonia(kctc 2208), Escherichia coli(kctc 1924), Salmonella Typhimurium(KCTC Table 1. Extraction yields, total phenolic, and total flavonoid content of ethanol extracts (70%, v/v) from sorghum varieties Cultivar Remark % TPC mg GAE/g 1925) 그리고효모 Candida albicans(kctc 7965), Pichia jadinii (KCTC 7293) 은 Korean Collection for Type Cultures(KCTC) 에서분양받아이용하였다. 피검균을액체배지 (micrococcus, nutrient, YM media) 에서배양하였으며, 항미생물활성은 Kobayashi 등의 two-fold dilution 법 (18) 을사용하여측정하였다. 미생물의증식을육안으로관찰하여세균의생육을억제하는가장낮은농도를나타내는최저억제농도 (MIC: minimum inhibitory concentration) 로나타내었다. Sample 무첨가구는 negative control 로 tetracycline 과 ketoconazole 은 positive control 로사용하였다. α-glucosidase 저해활성각수수추출물 50 µl 를 0.2 U/mL α-glucosidase 효소액 50 µl, 200 mm potassium phosphate buffer(ph 6.8) 50 µl 와혼합하여 37 o C 에서 15 분간배양한후 3mM pnpg(p-nitrophenyl-α-dglucopyranoside) 100 µl 를가하여 37 o C 에서 10 분간반응시켰다. 0.1 M sodium carbonate 750 µl 로반응을정지시키고 405 nm 에서흡광도를측정하였다. Sample 무첨가구는 negative control 로사용하였으며, 기질무첨가구는 blank 로사용하였다. Acarbose 를 positive control 로사용하였으며, α-glucosidase 저해활성은아래와같이계산하였다. Inhibition rate (%)={1 (ABS sample ABS blank )/ABS control } 100 TFC 3) mg QE/g Gumeunchalsusu GEC 3.6 ef4) 21.2 cd 1.0 jk Ginjangmoksusu GJM 3.5 ef 21.3 c 1.1 ijk Kkachisusu KKC 3.5 ef 19.6 i 0.7 l Mesusu MSS 3.8 def 22.7 a 2.0 ef Moktaksusu MT 4.5 abc 22.2 b 1.0 k Mongdangsusu MD 4.4 abcd 21.4 c 1.2 hi Bulgeunsaeksusu BES 3.9 cdef 21.4 c 2.3 d Bulgeunjangsusu BEJ 4.5 abc 20.4 de 1.3 h Bulgeunjangmoksusu BEJM 4.4 abcd 21.9 b 2.9 b Bulgeunchalsusu BEC 3.9 cdef 18.2 j 2.0 ef Bitjarususu BJR 4.2 bcde 22.9 a 2.2 de Susongsaengisusu SSSI 3.4 f 20.5 de 2.0 f Sigyeongsusu SG 3.6 ef 17.4 k 2.3 d Ilbanchalsusu IBC 3.7 ef 20.4 ef 1.2 hi Jangmoksusu JM 4.8 a 22.7 a 3.5 a Jangsususu JS 3.6 ef 19.8 hi 1.2 hij Jaeraechalsusu JRC 3.9 cdef 19.9 gh 1.6 g Chalsusu CSS 4.4 abcd 20.5 efg 1.3 h Chal(GS)susu CGS 4.7 ab 18.6 j 1.0 k Chal(JD)susu CJD 4.5 abcd 21.7 b 1.5 g Heuinjangmoksusu HJM 2.7 g 20.2 fgh 2.5 c Heuinsusu HSS 3.7 ef 16.4 l 1.0 k Extraction yield (%): weight of dry soluble solid (g)/weight of sample (g) 100 Total phenol content analysed as gallic acid equivalent (GAE) mg/g of extract, values are the mean±standard derivation of triplicates. 3) Total flavonoid content analysed as quercetin equivalent (QE) mg/g of extract, values are the mean±standard derivation of triplicates 4) Each value is mean±sd of triplicate determinations. Mean separation within columns by Duncan s multiple range test at 5% level.
600 한국식품과학회지제 42 권제 5 호 (2010) Table 2. Electron donationg ability of ethanol extracts (70%, v/v) from sorghum varieties EDA(%) Cultivar 2 µg/ml 6 µg/ml 10 µg/ml GEC 15 fgh3) 38 g 68 hi GJM 17 defg 50 e 79 e KKC 06 lm 18 j 29 m MSS 31 a 82 a 94 ab MT 18 cdef 65 c 91 bc MD 15 fgh 44 f 68 hi BES 19 bcde 58 d 86 d BEJ 22 bc 62 c 92 b BEJM 22 bc 69 b 94 ab BEC 11 hij 29 i 48 l BJR 20 bcd 57 d 87 d SSSI 13 ghij 32 hi 51 kl SG 09 jkl 20 j 32 m IBC 15 efgh 45 f 72 fg JM 19 cdef 50 e 75 f JS 07 klm 20 j 29 m JRC 10 ijk 31 hi 52 k CSS 12 ghij 35 h 57 j CGS 13 ghi 40 g 66 i CJD 19 cdef 63 c 89 cd HJM 13 ghi 46 f 71 gh HSS 04 m 08 k 14 n BHT 04 m 08 k 13 n BHA 23 b 55 d 74 fg α-tocopherol 30 a 73 b 97 a EDA(%): (1-absorbance value of sample/absorbance value of control) 100 For abbreviations see Table. 1. 3) Each value is mean±sd of triplicate determinations. Mean separation within columns by Duncan s multiple range test at 5% level. ABS sample : Absorbance of the experimental sample ABS blank : Absorbance of the blank ABS control : Absorbance of the control 통계분석모든실험은 3 회반복실험한후평균값과표준편차로표시하고, 각실험결과로부터 SPSS 11.5 를이용하여유의성을검정하였다. 결과및고찰 수율과총페놀및플라보노이드함량수수추출물에대한수율은 Table 1 에나타내었다. 70% ethanol 에추출한수수 22 개품종의수율은 2.7-4.8% 로나타났으며, 이와같은결과는 7 가지특수미의수율 1.4-5.6% 와유사한결과를보였으며 (19), 멕시코에서재배된보리의수율 (1.0-2.2%) 보다높게나타났다 (20). 수수중에서도장목수수, 찰 ( 금산 ) 수수, 목탁수수가각각 4.8, 4.7, 4.5% 로다른수수에비해높은수율을보였으며, 흰장목수수, 수송생이수수, 긴장목수수, 까치수수가각각 2.7, 3.4, 3.5, 3.5% 로낮은수율을보였다. 수수추출물의총페놀및플라보노이드함량은 Table 1 에나 Table 3. Reducing power of ethanol extracts (70%, v/v) from sorghum varieties Reducing power Cultivar 30 µl 60 µl 90 µl GEC 0.16 j 0.26 n 0.34 k GJM 0.20 ghi 0.33 ijk 0.45 h KKC 0.10 k 0.18 o 0.24 lm MSS 0.29 c 0.50 c 0.71 c MT 0.24 def 0.42 de 0.59 d MD 0.17 ij 0.33 ijkl 0.40 ij BES 0.22 efg 0.36 ghi 0.49 fg BEJ 0.21 fgh 0.38 efg 0.52 ef BEJM 0.24 def 0.42 de 0.56 d BEC 0.17 j 0.28 mn 0.35 k BJR 0.22 efg 0.37 fgh 0.52 e SSSI 0.18 hij 0.29 lmn 0.39 ij SG 0.09 k 0.17 o 0.26 l IBC 0.16 ij 0.30 jklm 0.42 i JM 0.26 d 0.44 d 0.58 d JS 0.09 k 0.16 o 0.22 m JRC 0.17 ij 0.28 mn 0.37 jk CSS 0.23 efg 0.42 de 0.58 d CGS 0.18 ij 0.33 ijkl 0.46 gh CJD 0.25 de 0.41 def 0.59 d HJM 0.18 ij 0.29 klmn 0.39 ij HSS 0.04 l 0.08 p 0.11 n BHT 0.37 b 0.63 b 0.84 b BHA 0.46 a 0.69 a 0.93 a α-tocopherol 0.19 hij 0.33 hij 0.51 ef For abbreviations see Table 1. Each value is mean±sd of triplicate determinations. Mean separation within columns by Duncan s multiple range test at 5% level. 타내었다. 수수 22 개품종을비교한결과총페놀함량은빗자루수수, 메수수, 장목수수순으로각각 22.9, 22.7, 22.7 mg GAE/ g 로높은함량을나타내었으며, 흰수수가 16.4 mg GAE/g 로가장낮은함량을나타내었다. Kong 등 (2 의보고에따르면백미, 추청현미쌀, 금종현미쌀은각각 11.1, 49.4 69.1 mg/100 g sample 의페놀성분을가지고있으며, Qingming 등 (2 은중국에서재배된보리를측정한결과 3.11 mg GAE/g 로수수보다낮은함량을보였다. 그리고 Dykes 등 (23) 의보고에따르면페놀화합물들을측정한결과 gallic acid 는하얀색수수, 노랑색수수, 빨강색수수, 갈색수수에서각각 19.7, 13.2, 46.0, 26.1 µg/g, dry wt 의함량을보였으며, cinnamic acid 는갈색수수에만 19.7 µg/g, dry wt 의함량을보였으며, vanillic acid 는빨간수수와갈색수수에만각각 19.2, 27.4 µg/g, dry wt 의함유를나타내었다. 이와같이수수품종별로페놀화합물들의함량이달라총페놀의함량이다른것을확인하였다. 플라보노이드는 0.7-3.5 mg QE/g 의함량을보여주었다. 22 품종중에서도까치수수가 0.7 mg QE/g 로가장낮은함량을나타낸반면에장목수수, 붉은장목수수, 흰장목수수가 3.5, 2.9, 2.5 mg QE/ g 로높은함량을보여주었다. 이결과는 Kwak 등 (7) 의보고에서도수수 (1.2 mg/wt) 가다른곡류인메밀 (1.4 mg/wt), 기장 (1.0 mg/ wt), 율무 (0.7 mg/wt) 보다유사하거나높은플라보노이드함량을보였으며이러한결과는수수에플라보노이드함량이높은것을확인할수있었다.
국내산수수 (Sorghum bicolor) 품종에따른전자공여능, 환원력, 항균활성및저해활성의비교 601 Table 4. Antimicrobial activity of 70% ethanol extract from Sorghum bicolor MIC (µg/ml) Sample Bacteria strain Yeast strain 3) B.s. (+) S.a. (+) E.c. (-) S.t. (-) K.p. (-) C.a. P.j. GEC 3) >1000 >1000 32 >1000 >1000 500 250 GJM >1000 >1000 16 >1000 1000 250 250 KKC >1000 >1000 1000 >1000 >1000 250 250 MSS >1000 >1000 32 >1000 >1000 250 250 MT >1000 >1000 250 >1000 >1000 500 250 MD >1000 >1000 250 >1000 >1000 500 250 BES 250 >1000 500 >1000 >1000 >1000 >1000 BEJ >1000 >1000 250 >1000 >1000 >1000 >1000 BEJM 250 >1000 125 >1000 >1000 250 250 BEC 1000 1000 250 >1000 >1000 250 250 BJR 250 >1000 500 >1000 >1000 >1000 >1000 SSSI 250 >1000 500 >1000 >1000 500 500 SG 250 250 8 >1000 >1000 500 500 IBC 1000 >1000 16 >1000 >1000 250 250 JM 250 500 63 >1000 1000 250 250 JS >1000 >1000 500 >1000 >1000 500 250 JRC 1000 >1000 500 >1000 >1000 500 500 CSS 1000 >1000 500 >1000 >1000 500 500 CGS >1000 >1000 8 >1000 >1000 250 250 CJD 1000 >1000 500 >1000 >1000 >1000 >1000 HJM 125 >1000 250 >1000 >1000 500 250 HSS 1000 >1000 250 >1000 >1000 500 500 Tetracycline 8 8 8 8 8 Ketoconazole 250 250 The MIC values against bacteria and yeast were determined by the serial two-fold dilution method. The growth of the bacteria and yeast were evaluated by the degree of turbidity of the culture with the naked eye. For abbreviations see Table 1. 3) S.a.: Staphylococus aureus KCTC 1916, B.s.: Bacillus subtilis KCTC 1021, K.p.: Klebsiella pneumonia KCTC 2208, E.c.: Escherichia coli KCTC 1924, S.t.: Salmonella Typhimurium KCTC 1925, P.j.: Pichia jadinii KCTC 7293, C.a.: Candida albicans KCTC 7965. DPPH 소거활성에대한전자공여능 (electron donating ability, EDA) 전자공여능은항산화측정에대표적으로쓰이는방법이다. 이실험에서쓰이는 DPPH는항산화활성을측정하기위한기질로사용하였으며, phenol, flavonoid와같은페놀성물질에대한항산화작용의지표라고알려져있다. 이와같은작용은활성라디칼에전자를공여하여식품중의지방산화억제와인체내노화를억제시킨다고보고하였다 (24). 수수추출물의 DPPH 소거활성을 2, 6, 10 µg/ml 농도로측정하여비교한결과는 Table 2 와같다. 10 µg/ml 농도에서는메수수, 붉은장목수수가각각 94.3, 94.0% 로높은활성을나타내었다. 이와같은결과는페놀계합성항산화제로널리사용되고있는 butylated hydroxyl toluene (BHT) 와비교해보았을때 22개품종의수수가훨씬높은활성을나타내었으며, 메수수와붉은장목수수는가장높은활성을나타낸 α-tocopherol과유사한활성을보이는것을알수있었다. 수수 22품종의전자공여능평균값은 66% 로, 재배지역에따른검정콩의평균값 ( 일품검정콩 (56%), 청자콩 (44%)) 보다높은활성을보였다 (25). 이결과는 Song 등 (26) 이보고한유색보리 40 계통의평균값 70% 와유사한활성을보였으며, 그중상위 23% 를비교하였을때수수 (92%) 가보리 (78%) 보다높은활성을나타내었다. 환원력측정이실험은 700 nm 에서 ferric-ferricyanide(fe 3+ ) 혼합물이수소를공여하여유리라디칼을안정화시켜 ferrous(fe 2+ ) 로전환하는환원력을흡광도값으로나타낸것이다. 70% ethanol 추출물로실험한결과는 Table 3 에나타내었다. 농도별로수수추출물의환원력을측정한결과농도가높아짐에따라활성이증가하는경향을보였으며, Qingming 등 (2 도농도의존적인경향을나타내었다. 22 개품종을검정한결과 90 µl 에서메수수 (OD 700 =0.7 가가장높은활성을나타냈으며, 다음으로목탁수수, 찰 ( 진도 ) 수수, 장목수수, 찰수수, 붉은장목수수가각각 0.59, 0.59, 0.58, 0.58, 0.56 의 OD 값으로높은활성을나타내었다. 이수수들은 α-tocopherol (OD 700 =0.5 보다높은활성을나타내었다. 수수추출물의항산화활성및총페놀함량을측정한결과, 메수수, 붉은장목수수, 목탁수수, 찰 ( 진도 ) 수수, 빗자루수수, 장목수수가높은항산화활성을나타냈으며, 높은페놀함량을보였다. 이결과는총페놀함량과항산화활성의상관관계가있는것을알수있었으며, Pasko 등 (27) 과 Dlamini 등 (28) 도총페놀함량이많을수록높은항산화활성이나타난다고보고하였다. 항산화활성실험중에서도 DPPH radical cation(r 2 =0.6200), Reducing power(r 2 =0.9075) 그리고 ABTS radical cation(r 2 =0.9973) 과밀접한관계를가지고있어총페놀의함량이높을수록항산화활성이좋은것을확인하
602 한국식품과학회지제 42 권제 5 호 (2010) Fig. 1. α-glucosidase inhibitory effect of ethanol extracts (70%, v/v) from sorghum varieties. For abbreviations see Table 1. Acar: Acarbose. 였다 (29). 그리고 Awika 등 (6) 의보고에따르면수수품종별로페놀화합물인 tannins 의함량차이를보였으며, 그중에서도 tannins 을함유한수수가페놀함량과항산화활성이높은것을확인하였다. 그러나 tannins 을함유한수수의 DPPH, ABTS, ORAC 항산화활성을측정결과각각 17.7-41.5, 61.6-125.0, 72.4-236.0 µmol-te/g 로활성의차이를나타내었다. 이와같이페놀화합물에따라항산화활성의차이가있는것을확인하였다. 항균실험식품의부패와변질을방지하기위한목적으로미생물을사멸시키거나증식을억제시키는합성항생제를사용한다. 이러한항생제사용이점차증가되면서부작용이일어나안전성문제가대두되고있는실정이다. 이러한문제점으로인하여요즘은인체에무해한천연물을이용하여천연항균성물질개발연구가활발히진행중이다 (30). 수수추출물의 MIC 를측정한결과 Table 4 와같다. 그람양성균인 B. subtilis 에서흰장목수수가 125 µg/ml 의 MIC 로다른수수보다높은활성을나타내었다. 그람음성균인 E. coli 에서는모든수수가높은억제활성을나타내었으며, 특히그중에서도시경수수와찰 ( 금산 ) 수수가각각 8µg/mL 로뛰어난활성을보여주었으며, 항생제인 tetracycline(mic=8 µg/ml) 과비교하였을때유사한활성을보였다. 그리고효모 P. jadinii 와 C. albicans 에서는붉은색수수, 붉은장수수, 빗자루수수, 찰 ( 진도 ) 수수를제외한대부분의수수추출물이 250-500 µg/ml 의최저억제농도를나타내었으며, 특히메수수, 까치수수, 긴장목수수, 붉은장 목수수, 붉은찰수수, 찰 ( 금산 ) 수수, 장목수수, 일반찰수수의경우는항생제인 ketoconazole 과유사한활성을나타내었다. 위와같은결과는 Kil 등 (3 의연구결과와비교하였을때효모 C. albicans 에서활성을확인할수없었으며, 이는시료추출용매에의한항균활성의차이를보이는것으로추측된다. Kim 등 (3 에서는페놀성물질인 phenolic acid 및 coumarin 류, flavonoid 류가단백질, 효소단백질, 기타거대한분자들과결합하여항산화및항균효과등의생리활성기능을가진다고보고하였다. 이러한보고를토대로수수추출물은총페놀, 총플라보노이드함량이높아항균활성이좋게나타난것으로예상되며, 이러한페놀성물질과항균활성과의상관관계를살펴본결과함량이높을수록항균활성에영향을미치는것을확인할수있었다. 수수추출물을대상으로추가적인항미생물활성물질분리실험이진행되어야할것으로사료된다. α-glucosidase 억제활성 α-glucosidase 는소장상피세포의 brush-border membrane 에존재하는효소또는단당류로서가수분해가일어나촉매역할을하며, α-glucosidase 에대한저해능은포도당의흡수를억제시켜, 식후혈당상승을감소시킨다 (33,34). 수수추출물을 5µg/mL 의농도로사용하여 α-glucosidase 에대한저해활성을검토한결과를 Fig. 1 에나타내었다. 모든수수가활성을보였으며, 그중에서도긴장목수수, 목탁수수, 붉은장목수수가각각 98% 로가장높은억제효과를보였으며, 장목수수, 수송생이수수도각각 97% 로높은
국내산수수 (Sorghum bicolor) 품종에따른전자공여능, 환원력, 항균활성및저해활성의비교 603 저해활성이보였다. 반면에흰장목수수, 일반찰수수, 흰수수는각각 49, 53, 58% 로상대적으로다른수수보다낮은활성을보였으며, positive control 로사용한 acarbose 는같은농도에서 99% 로수수와유사하거나높은저해활성을나타내었다. 또한이결과는페놀함량이높을수록항산화활성이좋았던수수와조금다른경향을보였다. 이는페놀함량과항당뇨활성에낮은상관관계를보이는것으로추측된다. Ranilla 등 (35) 의보고에따르면약용식물과약초의페놀함량과항산화활성의상관관계는 R 2 =0.81 로높은상관관계를나타내었으나, 항당뇨활성과는 R 2 =0.39 로낮은상관관계를나타내었다. 요 수수의기능성식품으로써이용가능성을조사하기위해수수의 70% ethanol 추출물의전자공여능, 환원력, 총페놀함량, 총플라보노이드함량, 항미생물, α-glucosidase 억제활성을측정하였다. 전자공여능측정결과 10 µg/ml 농도에서메수수, 붉은장목수수가 94% 로 BHT(13%), BHA(74%) 보다월등히높은활성을보였다. 환원력을측정한결과농도가높아짐에따라활성이증가하는경향을보였으며, 수수 22 개품종중에서메수수가 0.71 의 OD 값으로가장높은항산화활성을나타내었다. 추출물의총페놀함량은빗자루수수가 22.9 mg GAE/g 로높은함량을나타내었으며, 흰수수가 16.4 mg GAE/g 로가장낮은함량을보였다. 총플라보노이드함량은장목수수가 3.5 mg QE/g 로높은함량을보였다. 항미생물실험결과 E. coli 에서모든수수가활성을나타내었으며, 특히시경수수 (MIC=8 µg/ml) 와찰 ( 금산 ) 수수 (MIC=8 µg/ml) 가뛰어난활성을나타내었다. α-glucosidase 억제활성측정결과붉은장목수수, 목탁수수, 긴장목수수가 98% 로높은억제율을보여주었다. 약 감사의글 본논문은농촌진흥청에서시행한 2009 년 15 대어젠다농업연구개발사업 ( 과제번호, PJ006457) 의지원에의한연구결과의일부로이에감사드립니다. 문 1. 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