513
Hypoglycemic Activity of Olive Leaf M. Gonzalez', A. Zarzuelo1-3, M. J. Gamez', M. P. Utrilla1, J. Jimenez', andi. Osuna2 2
Departamento do Farmacologia, Facultad de Farmacia, Universidad de Granada, 18071 Granada, Spain Departamento de Bioquimica, Facultad de Medicina, Universidad de Granada, 18071 Granada, Spain Address for correspondence
Received: October 16, 1991
The other portion of the leaves was used to _____________
The hypoglycemic activity of olive leaf was
studied. Maximum hypoglycemic activity was obtained from samples collected in the winter months, especially in February. One of the compounds responsible for this activity was oleuropeoside, which showed activity at a
dose of 16mg/kg. This compound also demonstrated antidiabetic activity in animals with alioxan-induced diabetes. The hypoglycemic activity of this compound may result from two mechanisms: (a) potentiation of glucose-
induced insulin release, and (b) increased peripheral uptake of glucose.
obtain crude oleuropeoside (5). We determined the oleuropeoside
content in the crude residue by HPLC with a Waters chromatograph, using an RP-18 column (25cm x 2.5 cm), a Perkin-Elmer LC-235 diode array detector at 230 rim, and MeOH-H20 (7: 3) as the mobile phase at a flow rate of 1 mi/mm. Pure oleuropeoside (Extrasynthèse, Genay, France) was used as the internal standard.
Biological assays Female Wistar rats weighing 200— 250 g were used. All animals were fed Sanders S-b mixed diet.
Activity in normoglycemic animals The animals were fasted for 24 h prior to testing,
and were allowed to drink tap water ad libitum. Blood glucose
Key words
Olea europaea, olive leaf, hypoglycemic activity, oleuropeoside, seasonal variation.
concentration was determined and noted as initial glycemia (G0), then the sample was administred orally and glucose values were determined 30, 90, and 150 mm later. The percentage in variation glycemia was calculated as a time function by the formula: % Change in glycemia =
G — G0
x 100
G0
Introduction Olive leaf is known for a number of pharmacologic effects. After hypotensive action had been demonstrated (1— 4), a substance named oleuropeoside was credited with the hypotensive action of the leaf decoction
G0 and G were the values of initial glycemia and glycemia at 30, 90, and 150 mm. Animals in which distilled water
was administered were used as controls. The glucose-oxidase method was used for all determinations and the results were expressed as mg/100 ml.
Antidiabetic activity
(5).
Although olive leaf is also used in folk remedies as an antidiabetic, a search of the literature failed to find any scientific reports dealing with this activity. In this study we set out to verify whether olive leaf showed hypoglycemic and antihyperglycemic activities, under controlled laboratory conditions.
Diabetic animals were obtained by i.p. adminis-
tration of alloxan dissolved in distilled water (5%) in doses of 120mg/kg for 3 consecutive days. Blood glucose levels in alloxan-diabetic rats ranged from 250 to 350 mg/100 ml. The sample was administered orally and glucose values were determined 90 and 150 mm later.
Intestinal glucose absorption
Materials and Methods Plant material The plant material consisted of leaves of Olea europaea L. (Oleaceae) collected between November 1988 and October 1989 in Martos (province of Jaen, Spain). The sample, upon arrival in the laboratory, was powdered and frozen at — 10°C until use.
Preparation of extracts A portion of the powdered leaves was used to prepare a decoction (6), which was subsequently lyophilized and refrigerated at 4°C until use.
An intestinal perfusion technique (7, 8) was used to study the effects of crude oleuropeoside on intestinal absorption in rats fasted for 36 hand anesthetized with sodium pentobarbital. The perfusing solution was composed of the following (in gIl): 7.37 NaC1, 0.20 KC1, 0.065 NaH2PO4 x 2H,O, 0.2 13 MgC12 x 6H,O, 1.02
CaCl2, 0.6 NaHCO3 and 1.0 glucose, at pH 7.5. Perfusion rate was 10 mi/h to a total volume of 20 ml via a thermoregulated system set at 38°C.
The results were expressed as percentage glucose absorption, calculated from the amount of glucose in solution
before and after perfusion with the sample. Glucose absorption was also calculated in the group of animals which received no drugs (blank assay).
Downloaded by: NYU. Copyrighted material.
Abstract
514 Planta Med. 58(1992)
M. Gonzalez et al.
Peripheral glucose consumption was studied in rat diaphragm preparations from animals fasted for 36 h prior to sacrifice and exsaguination. Diaphragms were divided into two halves and incubated in accordance with Vallance-Owen's technique (9) at 37.2°C, with constant oxygenation, for 90mm and shaking at 90 cycles/mm. The nutrient solution was prepared with the following formula: 125 ml 1.3% NaHCO3 was aerated for 3 mm with carbogen, then added to 750 ml of saline solution. The result-
ant mixture was aerated for 10 mm and used immediately. Composition of the saline solution (in g/l) was: 9.50 NaCl, 0.40 KC1, 0.30 CaC12, 0.35 NaHCO3, 0.35 MgSO4 x 7H20, and 0.20 KH2PO4. Glucose was added to a final concentration of 3 g/l.
The results were expressed as glucose consumption (by subtracting glucose after incubation from glucose before incubation) per 10mg dry diaphragm. Dry weight was deter-
mined after oven drying the material at 105 'C for 120 mm. The absolute values thus obtained were used to calculate percentage increase in glucose consumption when hemidiaphragms were incubated in the presence and absence (blank assay) of drugs.
Pancreatic action Pancreatic islets were isolated using the collagenase (Worthington, 169 U/mg) method, and perfused as previously described (10). The medium used for incubation was a modified Krebs-Henseleit bicarbonate buffer (see the nutrient solution specified above under "Peripheral glucose consumption") containing 2.7 mmol/l glucose (basal), supplemented with 0.5 % bovine albumin and equilibrated against a mixture of 95% 02 and 5% CO2.
Insulin release was determined by radioimmunoassay before (basal) and after incubation of the islets in the presence of increasing concentrations of crude oleuropeoside at 0.2, 0.4, and 0.8 mg/ml, and the results were expressed in pI.U./ml of insulin.
Table I also shows the findings of the quantitative determinations of oleuropeoside. The highest percentages of this compound were recorded in winter, especially in February. The lowest percentages occurred in summer; decoctions of these samples showed no hypoglycemic effect.
On correlating the activities with the percentage of oleuropeoside, the quantitative variations in this compound may explain the modifications observed in hypoglycemic activity. When the olive leaf contained the highest
percentages of oleuropeoside, it also showed maximum hypoglycemic activity, whereas the absence of activity was associated with the lowest percentages of this compound (r = 0.805). These results suggest that oleuropeoside was the compound responsible for hypoglycemic activity. Crude oleuropeoside from olive leaves collected in February (70 % pure oleuropeoside) showed a significant hypoglycemic activity (Table 2) at doses of 16 and 32mg/kg. These results confirmed that oleuropeoside was responsthle for hypoglycemic activity in normoglucemic rats. Table 2
Hypoglycemic activity of crude oleuropeoside collected in February. % Change in glucose level
Dose
150mm
90mm
mg/kg
— 3,6 4.3
— 2.0
8
— 9.3
16
—19.6
32
—25.2 4.6"
— 5.7 —17.2 —27.2
Control
7.0 3.5'
5.6 6.6
5.1' 6.1°'
* p < 0.05, " p < 0.01. Statistical comparisons were based on Student's t test; tabular figures represent the mean SEM of lOvalues.
Table 3 Antidiabetic activity of crude oleuropeoside in alloxan-induced
Results and Discussion
hyperglycemia.
Hypoglycemic activity
% Change in glucose level
Dose
Tests in normoglycemic rats (Table 1) showed that the decoction of olive leaves collected in all
months except July, August, and September had hy-
90mm
mg/kg
29.0
Control 16
—17.5
12.9 12.9' 12.6
150mm
14.6
— 0.2
10.3 7.7
—48.2
10.5"
poglycemic effects at a dose of 0.5 g/kg. Maximum hy-
32
poglycemic activity was obtained from samples collected in the winter months, especially February.
* p < 0.05, °' p < 0.01. Statistical comparisons were based on Student's t test; tabular figures represent the mean SEM of lOvalues.
% Change in glucose level
Sample 30mm
90mm
2.7
Pure oleuropeoside 150mm
(%)
Table 1 Hypoglycemic activity of Olea europaea leaf decoction according to month of harvest and % of pure oleuropeoside (Control blood glucose
value: 85.7 5.2mg/lOOmI). Control January February March May June July August September October November December
18.5
3.1
— 9.6
5.5"
—17.0
2.7"
3.2
19.2 5.3
8.9
23.8 7.4 4.2
— 3.2 —22.8
8.9 10.1 6.7 10.2 12.9 6.8 6.3
11.1
2.0
—18.8 —31.6
5.5"
— 10.7
8.7'
—17.2 —13.4 — 4.7
6.4"
5.7
3.2°°
12.3°' 7.9 10.7
13.0 —14.6
4.8
2.9"
— 13.5
6.1°'
—22.3
2.5** 7.6**
5.3°'
6.7 —18.2 —40.1
1.5
3.8" 3.9°'
14.6
11.7
—10.8 —10.2 —11.6
10.1
21.8 19.2 10.7 — 10.5
—12.7
7.6 7.9 12.5 5.0 8.3
8.6' 5.7°'
0.51 0.71 0.56 0.42 0.27 0.17 0.07 0.28 0.28 0.39 0.61
p < 0.01. Statistical comparisons were based on Student's t test; tabular figures represent the p < 0.05, mean SEM of lOvalues.
Downloaded by: NYU. Copyrighted material.
Peripheral glucose consumption
Planta Med. 58(1992) 515
Hypoglycemic Activity of Olive Leaf
Antidiabetic activity
In animals with alloxan-induced diabetes, doses of 16 and 32mg/kg decreased blood glucose values (Table 3). On the basis of these results, we believe that oleuropeoside possesses hypoglycemic activity, and that this activity may be independent from the effects of insulin. Intestinal effects
Percentage glucose absorption before and after intestinal perfusion is shown in Table 4. At hypoglycemic doses, oleuropeoside did not inhthit intestinal glucose absorption.
Table 4 Changes in intestinal absorption of glucose with increasing doses of crude oleuropeoside. Dose (mg/mi per kg)
Glucose absorption (%)
Control
33.7
2.6
1.06 2.13
35.7 27.8 30.9
6.1
4.26
4.3 5.4
p < 0.05, ' p < 0.01. Statistical comparisons were based on Students t test; tabular figures represent the mean SEM of lOvalues.
Table 5 Percentage change in peripheral glucose uptake of rat diaphragm with increasing doses of crude oleuropeoside.
Oleuropeoside increased peripheral glu-
cose uptake in a concentration-dependent way (r = 0.98), at concentrations of iO- mg/mi and higher (Table 5). Pancreatic islet incubation
The presence of oleuropeoside in the islet incubation medium together with 2.7 mmol/1 glucose (basal) raised insulin levels. This effect was reversed at concentrations above 0.4 mg/mi (Table 6).
In conclusion, the results suggest that crude oleuropeoside, one of the compounds responsible for the hypoglycemic activity of olive leaf, possesses hypoglycemic and antidiahetic activities, and that this activity may be the result of two mechanisms: (a) potentiation of glucose-induced insulin release, and b) increased peripheral uptake of glucose.
Acknowledgements
Dose
Drugs
Oieuropeoside
49.2
4.2 2.2
10_2 mg/mI
57.5 73.3
5OylU/ml 500 ylU/mi 5000 ylU/mI
33.5 52.4 78.7
io- mg/mI 5 x l0 mg/mi
Insulin
Glucose uptake (%)
8.3 9.2 10.5
8.2
Tabularfigures represent the mean SEM of 10 values.
Table 6 Changes in insulin after incubation of pancreatic islets (glucose 2.7 mmol/l) with increasing concentrations of crude oleuropeoside.
Concentration mg/mi
Insulin values (ylU/ml)
54.3
Control
3.3
106.2 11.4"
0.2 0.4 0.8
83.5 67.7
3.1" 5.8
* p < 0.05, ' p < 0.01. Statistical comparisons were based on Student's I test; tabular figures represent the mean SEM of 8 values.
The authors thank Ms. Karen Shashok, who
References
translated the original manuscript into English.
—
1 Leclerc, H., Decaux, F., Valery-Leclerc, R. (1954) Rev. de Phytother. 2
6
' 8
18,7. Capretti, G. (1948) Giorn cli Clin. Med. 29, 394. Capretti. G. (1948) Giorn di Gun. Med. 29, 491.
Zarzuelo, A., Duarte, J., Jiméncz, J., Gonzalez, M., Utrilla, P. (1991) Planta Med. 57, 417. Panizzi, L., Scarpati. M. L.. Oriente, G. (1960) Gazz. Chim. Ital. 90, 1449. Farmacopea Espaflola IX Ed. (1954) Real Academia Nacional de Medicina p. 396. Solz, A., Ponz, F. (1974) Rev. Esp. Fisiol. 3, 207. Murillo, A., Sachez-Campos, M., Varela, G. (1972) Rev. Esp. Fisiol.
35, 115. J. (1954) Lancet 9, 68. ° Vallance-Oven, Osuna, J. I., Castillo. M., Rodriguez, E., Campillo, J. E., Osorio, C.
(1985) in; Phosphate and Mineral Homeostasis, (Massry, S. G., Olmer, M., Ritz, E., eds.), pp 509—515, Plenum Publishing Corp., New York.
Downloaded by: NYU. Copyrighted material.
Peripheral glucose consumption
Hypoglycemic Activity of Olive Leaf M. Gonzalez', A. Zarzuelo1-3, M. J. Gamez', M. P. Utrilla1, J. Jimenez', andi. Osuna2 2
Departamento do Farmacologia, Facultad de Farmacia, Universidad de Granada, 18071 Granada, Spain Departamento de Bioquimica, Facultad de Medicina, Universidad de Granada, 18071 Granada, Spain Address for correspondence
Received: October 16, 1991
The other portion of the leaves was used to _____________
The hypoglycemic activity of olive leaf was
studied. Maximum hypoglycemic activity was obtained from samples collected in the winter months, especially in February. One of the compounds responsible for this activity was oleuropeoside, which showed activity at a
dose of 16mg/kg. This compound also demonstrated antidiabetic activity in animals with alioxan-induced diabetes. The hypoglycemic activity of this compound may result from two mechanisms: (a) potentiation of glucose-
induced insulin release, and (b) increased peripheral uptake of glucose.
obtain crude oleuropeoside (5). We determined the oleuropeoside
content in the crude residue by HPLC with a Waters chromatograph, using an RP-18 column (25cm x 2.5 cm), a Perkin-Elmer LC-235 diode array detector at 230 rim, and MeOH-H20 (7: 3) as the mobile phase at a flow rate of 1 mi/mm. Pure oleuropeoside (Extrasynthèse, Genay, France) was used as the internal standard.
Biological assays Female Wistar rats weighing 200— 250 g were used. All animals were fed Sanders S-b mixed diet.
Activity in normoglycemic animals The animals were fasted for 24 h prior to testing,
and were allowed to drink tap water ad libitum. Blood glucose
Key words
Olea europaea, olive leaf, hypoglycemic activity, oleuropeoside, seasonal variation.
concentration was determined and noted as initial glycemia (G0), then the sample was administred orally and glucose values were determined 30, 90, and 150 mm later. The percentage in variation glycemia was calculated as a time function by the formula: % Change in glycemia =
G — G0
x 100
G0
Introduction Olive leaf is known for a number of pharmacologic effects. After hypotensive action had been demonstrated (1— 4), a substance named oleuropeoside was credited with the hypotensive action of the leaf decoction
G0 and G were the values of initial glycemia and glycemia at 30, 90, and 150 mm. Animals in which distilled water
was administered were used as controls. The glucose-oxidase method was used for all determinations and the results were expressed as mg/100 ml.
Antidiabetic activity
(5).
Although olive leaf is also used in folk remedies as an antidiabetic, a search of the literature failed to find any scientific reports dealing with this activity. In this study we set out to verify whether olive leaf showed hypoglycemic and antihyperglycemic activities, under controlled laboratory conditions.
Diabetic animals were obtained by i.p. adminis-
tration of alloxan dissolved in distilled water (5%) in doses of 120mg/kg for 3 consecutive days. Blood glucose levels in alloxan-diabetic rats ranged from 250 to 350 mg/100 ml. The sample was administered orally and glucose values were determined 90 and 150 mm later.
Intestinal glucose absorption
Materials and Methods Plant material The plant material consisted of leaves of Olea europaea L. (Oleaceae) collected between November 1988 and October 1989 in Martos (province of Jaen, Spain). The sample, upon arrival in the laboratory, was powdered and frozen at — 10°C until use.
Preparation of extracts A portion of the powdered leaves was used to prepare a decoction (6), which was subsequently lyophilized and refrigerated at 4°C until use.
An intestinal perfusion technique (7, 8) was used to study the effects of crude oleuropeoside on intestinal absorption in rats fasted for 36 hand anesthetized with sodium pentobarbital. The perfusing solution was composed of the following (in gIl): 7.37 NaC1, 0.20 KC1, 0.065 NaH2PO4 x 2H,O, 0.2 13 MgC12 x 6H,O, 1.02
CaCl2, 0.6 NaHCO3 and 1.0 glucose, at pH 7.5. Perfusion rate was 10 mi/h to a total volume of 20 ml via a thermoregulated system set at 38°C.
The results were expressed as percentage glucose absorption, calculated from the amount of glucose in solution
before and after perfusion with the sample. Glucose absorption was also calculated in the group of animals which received no drugs (blank assay).
Downloaded by: NYU. Copyrighted material.
Abstract
514 Planta Med. 58(1992)
M. Gonzalez et al.
Peripheral glucose consumption was studied in rat diaphragm preparations from animals fasted for 36 h prior to sacrifice and exsaguination. Diaphragms were divided into two halves and incubated in accordance with Vallance-Owen's technique (9) at 37.2°C, with constant oxygenation, for 90mm and shaking at 90 cycles/mm. The nutrient solution was prepared with the following formula: 125 ml 1.3% NaHCO3 was aerated for 3 mm with carbogen, then added to 750 ml of saline solution. The result-
ant mixture was aerated for 10 mm and used immediately. Composition of the saline solution (in g/l) was: 9.50 NaCl, 0.40 KC1, 0.30 CaC12, 0.35 NaHCO3, 0.35 MgSO4 x 7H20, and 0.20 KH2PO4. Glucose was added to a final concentration of 3 g/l.
The results were expressed as glucose consumption (by subtracting glucose after incubation from glucose before incubation) per 10mg dry diaphragm. Dry weight was deter-
mined after oven drying the material at 105 'C for 120 mm. The absolute values thus obtained were used to calculate percentage increase in glucose consumption when hemidiaphragms were incubated in the presence and absence (blank assay) of drugs.
Pancreatic action Pancreatic islets were isolated using the collagenase (Worthington, 169 U/mg) method, and perfused as previously described (10). The medium used for incubation was a modified Krebs-Henseleit bicarbonate buffer (see the nutrient solution specified above under "Peripheral glucose consumption") containing 2.7 mmol/l glucose (basal), supplemented with 0.5 % bovine albumin and equilibrated against a mixture of 95% 02 and 5% CO2.
Insulin release was determined by radioimmunoassay before (basal) and after incubation of the islets in the presence of increasing concentrations of crude oleuropeoside at 0.2, 0.4, and 0.8 mg/ml, and the results were expressed in pI.U./ml of insulin.
Table I also shows the findings of the quantitative determinations of oleuropeoside. The highest percentages of this compound were recorded in winter, especially in February. The lowest percentages occurred in summer; decoctions of these samples showed no hypoglycemic effect.
On correlating the activities with the percentage of oleuropeoside, the quantitative variations in this compound may explain the modifications observed in hypoglycemic activity. When the olive leaf contained the highest
percentages of oleuropeoside, it also showed maximum hypoglycemic activity, whereas the absence of activity was associated with the lowest percentages of this compound (r = 0.805). These results suggest that oleuropeoside was the compound responsible for hypoglycemic activity. Crude oleuropeoside from olive leaves collected in February (70 % pure oleuropeoside) showed a significant hypoglycemic activity (Table 2) at doses of 16 and 32mg/kg. These results confirmed that oleuropeoside was responsthle for hypoglycemic activity in normoglucemic rats. Table 2
Hypoglycemic activity of crude oleuropeoside collected in February. % Change in glucose level
Dose
150mm
90mm
mg/kg
— 3,6 4.3
— 2.0
8
— 9.3
16
—19.6
32
—25.2 4.6"
— 5.7 —17.2 —27.2
Control
7.0 3.5'
5.6 6.6
5.1' 6.1°'
* p < 0.05, " p < 0.01. Statistical comparisons were based on Student's t test; tabular figures represent the mean SEM of lOvalues.
Table 3 Antidiabetic activity of crude oleuropeoside in alloxan-induced
Results and Discussion
hyperglycemia.
Hypoglycemic activity
% Change in glucose level
Dose
Tests in normoglycemic rats (Table 1) showed that the decoction of olive leaves collected in all
months except July, August, and September had hy-
90mm
mg/kg
29.0
Control 16
—17.5
12.9 12.9' 12.6
150mm
14.6
— 0.2
10.3 7.7
—48.2
10.5"
poglycemic effects at a dose of 0.5 g/kg. Maximum hy-
32
poglycemic activity was obtained from samples collected in the winter months, especially February.
* p < 0.05, °' p < 0.01. Statistical comparisons were based on Student's t test; tabular figures represent the mean SEM of lOvalues.
% Change in glucose level
Sample 30mm
90mm
2.7
Pure oleuropeoside 150mm
(%)
Table 1 Hypoglycemic activity of Olea europaea leaf decoction according to month of harvest and % of pure oleuropeoside (Control blood glucose
value: 85.7 5.2mg/lOOmI). Control January February March May June July August September October November December
18.5
3.1
— 9.6
5.5"
—17.0
2.7"
3.2
19.2 5.3
8.9
23.8 7.4 4.2
— 3.2 —22.8
8.9 10.1 6.7 10.2 12.9 6.8 6.3
11.1
2.0
—18.8 —31.6
5.5"
— 10.7
8.7'
—17.2 —13.4 — 4.7
6.4"
5.7
3.2°°
12.3°' 7.9 10.7
13.0 —14.6
4.8
2.9"
— 13.5
6.1°'
—22.3
2.5** 7.6**
5.3°'
6.7 —18.2 —40.1
1.5
3.8" 3.9°'
14.6
11.7
—10.8 —10.2 —11.6
10.1
21.8 19.2 10.7 — 10.5
—12.7
7.6 7.9 12.5 5.0 8.3
8.6' 5.7°'
0.51 0.71 0.56 0.42 0.27 0.17 0.07 0.28 0.28 0.39 0.61
p < 0.01. Statistical comparisons were based on Student's t test; tabular figures represent the p < 0.05, mean SEM of lOvalues.
Downloaded by: NYU. Copyrighted material.
Peripheral glucose consumption
Planta Med. 58(1992) 515
Hypoglycemic Activity of Olive Leaf
Antidiabetic activity
In animals with alloxan-induced diabetes, doses of 16 and 32mg/kg decreased blood glucose values (Table 3). On the basis of these results, we believe that oleuropeoside possesses hypoglycemic activity, and that this activity may be independent from the effects of insulin. Intestinal effects
Percentage glucose absorption before and after intestinal perfusion is shown in Table 4. At hypoglycemic doses, oleuropeoside did not inhthit intestinal glucose absorption.
Table 4 Changes in intestinal absorption of glucose with increasing doses of crude oleuropeoside. Dose (mg/mi per kg)
Glucose absorption (%)
Control
33.7
2.6
1.06 2.13
35.7 27.8 30.9
6.1
4.26
4.3 5.4
p < 0.05, ' p < 0.01. Statistical comparisons were based on Students t test; tabular figures represent the mean SEM of lOvalues.
Table 5 Percentage change in peripheral glucose uptake of rat diaphragm with increasing doses of crude oleuropeoside.
Oleuropeoside increased peripheral glu-
cose uptake in a concentration-dependent way (r = 0.98), at concentrations of iO- mg/mi and higher (Table 5). Pancreatic islet incubation
The presence of oleuropeoside in the islet incubation medium together with 2.7 mmol/1 glucose (basal) raised insulin levels. This effect was reversed at concentrations above 0.4 mg/mi (Table 6).
In conclusion, the results suggest that crude oleuropeoside, one of the compounds responsible for the hypoglycemic activity of olive leaf, possesses hypoglycemic and antidiahetic activities, and that this activity may be the result of two mechanisms: (a) potentiation of glucose-induced insulin release, and b) increased peripheral uptake of glucose.
Acknowledgements
Dose
Drugs
Oieuropeoside
49.2
4.2 2.2
10_2 mg/mI
57.5 73.3
5OylU/ml 500 ylU/mi 5000 ylU/mI
33.5 52.4 78.7
io- mg/mI 5 x l0 mg/mi
Insulin
Glucose uptake (%)
8.3 9.2 10.5
8.2
Tabularfigures represent the mean SEM of 10 values.
Table 6 Changes in insulin after incubation of pancreatic islets (glucose 2.7 mmol/l) with increasing concentrations of crude oleuropeoside.
Concentration mg/mi
Insulin values (ylU/ml)
54.3
Control
3.3
106.2 11.4"
0.2 0.4 0.8
83.5 67.7
3.1" 5.8
* p < 0.05, ' p < 0.01. Statistical comparisons were based on Student's I test; tabular figures represent the mean SEM of 8 values.
The authors thank Ms. Karen Shashok, who
References
translated the original manuscript into English.
—
1 Leclerc, H., Decaux, F., Valery-Leclerc, R. (1954) Rev. de Phytother. 2
6
' 8
18,7. Capretti, G. (1948) Giorn cli Clin. Med. 29, 394. Capretti. G. (1948) Giorn di Gun. Med. 29, 491.
Zarzuelo, A., Duarte, J., Jiméncz, J., Gonzalez, M., Utrilla, P. (1991) Planta Med. 57, 417. Panizzi, L., Scarpati. M. L.. Oriente, G. (1960) Gazz. Chim. Ital. 90, 1449. Farmacopea Espaflola IX Ed. (1954) Real Academia Nacional de Medicina p. 396. Solz, A., Ponz, F. (1974) Rev. Esp. Fisiol. 3, 207. Murillo, A., Sachez-Campos, M., Varela, G. (1972) Rev. Esp. Fisiol.
35, 115. J. (1954) Lancet 9, 68. ° Vallance-Oven, Osuna, J. I., Castillo. M., Rodriguez, E., Campillo, J. E., Osorio, C.
(1985) in; Phosphate and Mineral Homeostasis, (Massry, S. G., Olmer, M., Ritz, E., eds.), pp 509—515, Plenum Publishing Corp., New York.
Downloaded by: NYU. Copyrighted material.
Peripheral glucose consumption
