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Anti-diabetic potential of Barleria lupulina extract in rats
Phytomedicine 11: 202–205, 2004 http://www.elsevier-deutschland.de/phymed
Anti-diabetic potential of Barleria lupulina extract in rats V. Suba, T. Murugesan, G. Arunachalam, S. C. Mandal, and B. P. Saha Department of Pharmaceutical Technology, Jadavpur University, Calcutta, India
Summary We have undertaken a study to evaluate the anti-hyperglycemic effect of a methanol extract of aerial parts of Barleria lupulina Lindl. (Acanthaceae) in streptozotocin-diabetic rats, based on folkloric reports its use as an anti-diabetic agent. The extract exerted significant (p < 0.05) anti-hyperglycemic efficacy at all levels tested from 4 h after its administration, as compared with the control group, and the effect was also prolonged up to 12 h. The extract at doses of 200 mg kg–1 body wt. and above exhibited a maximum activity (p < 0.001) at 12 h after administration. The most significant activity (15.35% blood glucose reduction) was observed for the group administered 300 mg kg–1 body wt. at 12 h after administration, while the standard drug glibenclamide (10 mg/kg–1 body wt.) showed an 18.80% reduction of blood glucose at the same time interval. Based on our current results, it appears that the methanol extract of aerial parts of Barleria lupulina Lindl. shows a pronounced blood-glucose-lowering potential in streptozotocin hyperglycemic rats, and is thus provided with a pharmacological support of the folklore claims of anti-diabetic activity. Key words: Barleria lupulina, methanol extract (MEBL), anti-diabetic, Hypoglycemia
Introduction Diabetics have long been treated orally with several medicinal plants or their extracts, based on folkloric claims (Akhtar et al. 1980). Synthetic hypoglycemic agents can produce serious side-effects, including hematological coma and disturbances of liver and kidney. In addition, they are not suitable for use during pregnancy (Larner, 1985). Therefore, the search for more effective and safer hypoglycemic agents has continued to be an important area for research. Following the recommendations made by the WHO on the beneficial uses of medicinal plants for the treatment of diabetes mellitus (The WHO Expert Committee, 1980), investigations of hypoglycemic agents from medicinal plants have also become more important. Barleria lupulina Lindl. (Acanthaceae), a plant used in folkloric Indian medicine is known locally as “Vishallakarani”. The plant is distributed chiefly in the 0944-7113/04/11/02–03-202 $ 30.00/0
mountains of southern and western India (Anonymous, 1996) and has long been cultivated as both an ornamental and medicinal plant. The plant is used traditionally for various ailments, including mental illness, fever, pain, and diabetes, and as a diuretic (Chopra, 1968). Phytochemical studies on this plant are sparse and deal only with the leaf and aerial parts of the plant. The isolation of an iridoid glucoside from Barleria lupulina has been reported (Byrne et al. 1987; Suksamran et al. 1986; Tuntiwachwrttikul et al. 1998; Kanchanapoom et al. 2001), and a betaine compound has been isolated from the leaves (Tuntiwachwuttikul et al. 1998). To the best of our knowledge, only studies on the anti-HSV-2 activity of Barleria lupulina (Yoosook et al. 1999 and Yoosook et al. 2000), and the anti-inflammatory activity of an iridoid glucoside isolated from the plant (Suksamran et al. 1986) have been
Anti-diabetic potential of Barleria lupulina extract in rats published, and no other information on its pharmacological properties have yet appeared. Some other species of Barleria have been tested for their hypoglycemic potential and found to be active of B. cristata, B. prionitis; Dhar et al. 1968; Bhakuni et al. 1969; Dhawan et al. 1977; Rahman and Zaman, 1989). These reports justify our interest in further studies of this plant. The pharmacological activities of this plant extract are currently being studied in our laboratory. In the study reported here, we have evaluated the glucose-lowering effect of a methanol extract of the aerial parts of Barleria lupulina (MEBL) in streptozotocin hyperglycemic rats, to establish pharmacological evidence in support of the folkloric claim of anti-diabetic activity.
Materials and Methods Plant material
Aerial parts of Barleria lupulina (Acanthaceae) were collected during the winter season (October-December) from Jhilimili, Bankura district, West Bengal, India, and authentication of the plant specimen was established by the Botanical Survey of India, Shibpur, Howrah. The voucher specimen (No: CNH/I-I (52), 2000-Tech.II) has been deposited in our departmental herbarium for future reference. Extraction procedure
The aerial parts were dried and pulverized to a coarse powder. The powder was passed through a 40-mesh sieve and extracted exhaustively with 90% v/v methanol in a Soxhlet apparatus. The extract was evaporated in vacuo until all the solvent had been removed, to yield an extract sample a 10. 8% w/w. The chemical make-up of the extract was analyzed using a qualitative test and found to contain flavonoids, steroids and tannins. These were confirmed by the tic study (hRf values). The extract was stored in the refrigerator and a weighed amount was prepared in propylene glycol for the present investigation. Test animals
Male Wistar rats weighing between 150–200 g each were used for the investigation. The animals were housed at a temperature of 21 ± 20 °C, with humidity of 55 ± 10% and a 12-h light-dark cycle (lights on at 0600 h). Rats were supplied with a standard pellet diet and tap water was freely available. Toxocological study
The determination of LD50 values of the methanolic extract of Barleria lupulina was performed in albino mice following the method of Ghosh (1984).
203
Blood collection
Blood samples were collected in heparinized tubes from the tail veins of the rats and plasma was separated within 30 min of withdrawal, for the determination of glucose concentration. Effect of extract in streptozotocin-hyperglycemic rats
Groups of rats, fasted for 18 h, were made hyperglycemic by intraperitoneal injection of streptozotocin (Sigma USA) dissolved in citrate buffer (pH 4.3), at a dose of 50 mg/kg–1 body wt. After 48 h, their plasma glucose levels were estimated and moderately streptozotocin-hyperglycemic rats (Chattopadhyay, 1993), having plasma glucose levels above 250 mg (%) were selected and divided into groups of 6 animals each. One group received glibenclamide (10 mg/kg body wt., p.o) and a control group received propylene glycol (10 ml/kg body wt.). Other groups were administered MEBL at oral doses of 100, 200 and 300 mg/kg body wt. (i.p). Blood glucose concentrations were measured at 0, 4, 8 and 12 h after drug treatment by the orthotoluidine method (Hultman, 1995; Hyavariner et al. 1962). Statistical analysis
The data are represented as Mean ± S. E. M., and statistical significance between treated and control groups was analyzed using of ANOVA, followed by Dunnet’s t-test. (Woodson, 1987).
Result and Discussion Toxicity study
On the basis of the toxicity study, the LD50 value of the plant extract in mice was 4.5 g/kg body wt. (p.o) and 3.7 g/kg body wt. (i.p). The extract (MEBL) exhibited significant (p < 0.01) anti-hyperglycemic efficacy from 4 h after its oral administration at all doses tested, when compared control group values, and the effect was prolonged up to 12 h. The extract at doses of 200 mg/kg body wt. and above shwed maximum activity (p < 0.001) at 12 h after administration. The high percentage (15.35%) of blood-glucose-lowering potential was observed in the group administered with 300 mg/kg body wt. extract at 12 h after administration, while the standard drug, glibenclamide (10 mg/kg body wt.) caused an 18.80% reduction in blood glucose level at the same time interval (Table 1). The methanol extract of the aerial parts of Barleria lupulina was also tested for its hypoglycemic effect in normal rat,s and was found to have no influence on normal glucose concentration (data not reported).
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V. Suba et al.
Table 1. Anti-diabetic activity of Barleria lupulina extract in streptozotocin-hyperglycemic rats. Treatment and dose
Plasma glucose concentration in mg% Time after treatment (in h) 0
4
8
12
Control 10 ml/kg1 body wt.
272.50 ± 1.11
271.66 ± 1.05
268.33 ± 3.80
265.83 ± 5.00
MEBL 100 mg/kg body wt.
269.16 ± 1.02
254.83 ± 1.25* (6.19)
253.33 ± 2.45* (5.59)
240.83 ± 3.75** (9.40)
MEBL 200 mg/kg body wt.
265.00 ± 2.47
252.50 ± 3.04* (7.05)
245.83 ± 2.45** (8.38)
230.00 ± 1.70** (13.47)
MEBL 300 mg/kg body wt.
265.00 ± 1.63
251.66 ± 4.47* (7.36)
240.00 ± 3.75** (10.55)
225.00 ± 4.60** (15.35)
Glibenclamide 10 mg/kg body wt.
265.00 ± 2.62
242.50 ± 2.45** (10.73)
238.33 ± 4.83** (11.18)
215.84 ± 3.75** (18.80)
Each value represents Mean ± S.E.M. (n = 6). * – p < 0.01, ** – p < 0.001,versus control (Propylene glycol). Figure in the parenthesis denotes percentage of reduction (plasma glucose). MEBL – Methanol extract of aerial parts of Barleria lupulina.
Discussion
From the present experimental results it can be suggested that the extract acts in a fashion similar to glibenclamide, the standard anti-diabetic drug. This similarity to glibenclamide will be a subject of further invistigations. Glilbenclamide and a natural hypoglycemic product have been reported to be effective in moderately streptozotocin-diabetic animals and ineffective in severely diabetic rats (Ivorra et al. 1988; Sharma et al. 1997). Phytochemical analysis showed that the major chemical constituents of the extract (MEBL) were flavonoids, steroids and tannins. Over 150 plant extracts and some of their active principles, including flavonoids, are known for the treatment of diabetes (Choi et al. 1991; Erenmemisoglu et al. 1995; Meiselman et al. 1976). Moreover, tannin-containing drugs demonstrated anti-diabetic activity (Iwu, 1980; Iwu, 1983). In our study we have also isolated the flavonoid quercetin from the plant extract. On the basis of previous reports, it is possible that the presence of flavonoids is responsible for the observed anti-diabetic activity.
Reference Akhtar FM, Ali MR (1980) Study of the anti-diabetic effect of a compound medicinal plant prescription in normal and diabetic rabbit. J Pakistan Med Assoc 34: 239–244
Anonymous (1966) The Wealth of India. Vol I. Publication and Information Directorate, CSIR, New Delhi, p 175 Bhakuni OS, Dhar ML, Dhar MM, Dhawan BN, Mehrotra BN (1969) Screen of Indian Plants for Biological Activity. Part II. Indian J Exp Biol 7: 250–262 Byrne LT, Sasse JM, Skelton BW, Suksamran A, White AH (1987) The minor iridoid glycosides of Barleria lupulina isolation, crystal structure and plant growth-inhibiting properties of 6-o-Acetylshanzhiside methyl ester. Aust J Chem 40: 785–794 Chattopadhya RR (1993) Hypoglycemic effect of Ocimum sanctum leaf in normal and streptozotocin diabeic rats. Indian J Exp Biol 31: 891–893 Chopra RN, Nayar SL, Chopra IC (1968) Glossary of Indian Medicinal Plants. Academic Publishers, New Delhi, India; pp 20 Choi JS, Yokozawa T, Oura H (1991) Improvement of hyperglycemia and methanolic extract of Prunus davidana stems and its main component, prurin. Planta Med 57: 208–211 Dhar ML, Dhar MM, Dhawan N, Mehrotra BN, Ray C (1968). Screening of Indian Plants for Biological Activity: Part I. Indian J Exp Biol 6: 232–247 Dhawan BN, Patnaik GK, Rastogi RP, Singh KK, Tandon JS (1977) Screening of Indian Plants for Biological Activity, VI. Indian J Exp Biol 15: 208–219 Erenmemisoglu A, Kelestimur F, Koker AH, Ustun H, Tekol Y, Ustdal M (1995) Hypoglycaemic effect of Zizyphus jujuba leaves. J Pharm Pharmacol 47: 72–74 Ghosh MN (1984). Fundamental of Experimental Pharmacology, 2nd Edn. Scientific Book Agency, Calcutta, India. pp 153
Anti-diabetic potential of Barleria lupulina extract in rats Hultman E (1959) Rapid specific method for determination of aldo saccharides in body fluids. Nature 183: 108–109 Hyavariner A, Nikkita E (1962) Specific determination of Blood glucose with ortho toluidine. Clin Chim Acta 7: 140–143 Ivorra MD, Paya M, Villar A (1988) Hypoglycemic and insulin release effects of tormentic acid: a new hypoglycemic natural product. Planta Med 54: 282–285 Iwu MM (1983) Hypoglycemic properties of Bridelia ferruginea leaves. Fitoterapia 54: 243–248 Iwu MM (1980) Antidiabetic properties of Bridelia ferruginea leaves. Planta Med 39: 247 Kanchanapoom T, Kasai R, Yamasaki K (2001) Iridoid Glucosides from Barleria lupulina. Phytochemistry 58: 337–341 Larner J (1985). Insulin and oral hypoglycemic drug, Glucogan. In: Gilman AG, Goodman LS, Rall IW, Murad F (Eds). The Pharmacological basis of Therapeutics, 7th edition, Macmillan, NewYork, pp 1490–1516 Meiselman HL, Halpern BP, Dateo GP (1976). Reduction of sweetness judgements by extracts from the leaves of Zizyphus jujuba. Physiol Behav 17: 313–317 Rahman Q-U, Zaman K (1989). Medicinal plants with hypoglycemic activity. J Ethnopharmacol 26: 1–55 Sharma SR, Dwivedi SK, Swarup D (1997) Hypoglycemic, antihyperglycemic, hypolipidemic activities of Caesalpinia bonducella seeds in rats. J Ethnopharmacol 58: 39–44
205
Suksamran A (1986) Iridoid glucosides from Barleria lupulina. J Nat Prod 49: 179 The WHO Expert Committee on Diabetes Mellitus, Technical Report Series World Health Organization, Geneva. 1980 Tuntiwachwuttikul P, Pandiaroen O, Taylor WC (1998) Iridoid glucosides of Barleria lupulina. Phytochemistry 49: 163–166 Woodson RF (1987) Statistical Methods for the Analysis of Biomedical Data, Wiley Series in Probability and Mathematical Statistics. Wiley, Chichester. Pp 315–316, Yoosook C, Panpisutchai Y, Chaichana S, Santisuk T, Reutrakul V (1999) Evaluation of Anti-HSV-2 activities of Barleria lupulina and Clicanthus nutans. J Ethnopharmacol 67: 179–187 Yoosook C, Bunyapraphatsara N, Boonyakiat Y, Kantasuk C (2000) Anti-Herpes simplex virus activities of crude water extracts of Thai medicinal plants. Phytomedicine 6: 411–419
Address B. P. Saha, Department of Pharmaceutical Technology, Jadavpur University, Calcutta - 700 032, India Tel.: 033-2413-6303; Fax: 91-33-23357254; e-mail: [email protected], [email protected]
Anti-diabetic potential of Barleria lupulina extract in rats V. Suba, T. Murugesan, G. Arunachalam, S. C. Mandal, and B. P. Saha Department of Pharmaceutical Technology, Jadavpur University, Calcutta, India
Summary We have undertaken a study to evaluate the anti-hyperglycemic effect of a methanol extract of aerial parts of Barleria lupulina Lindl. (Acanthaceae) in streptozotocin-diabetic rats, based on folkloric reports its use as an anti-diabetic agent. The extract exerted significant (p < 0.05) anti-hyperglycemic efficacy at all levels tested from 4 h after its administration, as compared with the control group, and the effect was also prolonged up to 12 h. The extract at doses of 200 mg kg–1 body wt. and above exhibited a maximum activity (p < 0.001) at 12 h after administration. The most significant activity (15.35% blood glucose reduction) was observed for the group administered 300 mg kg–1 body wt. at 12 h after administration, while the standard drug glibenclamide (10 mg/kg–1 body wt.) showed an 18.80% reduction of blood glucose at the same time interval. Based on our current results, it appears that the methanol extract of aerial parts of Barleria lupulina Lindl. shows a pronounced blood-glucose-lowering potential in streptozotocin hyperglycemic rats, and is thus provided with a pharmacological support of the folklore claims of anti-diabetic activity. Key words: Barleria lupulina, methanol extract (MEBL), anti-diabetic, Hypoglycemia
Introduction Diabetics have long been treated orally with several medicinal plants or their extracts, based on folkloric claims (Akhtar et al. 1980). Synthetic hypoglycemic agents can produce serious side-effects, including hematological coma and disturbances of liver and kidney. In addition, they are not suitable for use during pregnancy (Larner, 1985). Therefore, the search for more effective and safer hypoglycemic agents has continued to be an important area for research. Following the recommendations made by the WHO on the beneficial uses of medicinal plants for the treatment of diabetes mellitus (The WHO Expert Committee, 1980), investigations of hypoglycemic agents from medicinal plants have also become more important. Barleria lupulina Lindl. (Acanthaceae), a plant used in folkloric Indian medicine is known locally as “Vishallakarani”. The plant is distributed chiefly in the 0944-7113/04/11/02–03-202 $ 30.00/0
mountains of southern and western India (Anonymous, 1996) and has long been cultivated as both an ornamental and medicinal plant. The plant is used traditionally for various ailments, including mental illness, fever, pain, and diabetes, and as a diuretic (Chopra, 1968). Phytochemical studies on this plant are sparse and deal only with the leaf and aerial parts of the plant. The isolation of an iridoid glucoside from Barleria lupulina has been reported (Byrne et al. 1987; Suksamran et al. 1986; Tuntiwachwrttikul et al. 1998; Kanchanapoom et al. 2001), and a betaine compound has been isolated from the leaves (Tuntiwachwuttikul et al. 1998). To the best of our knowledge, only studies on the anti-HSV-2 activity of Barleria lupulina (Yoosook et al. 1999 and Yoosook et al. 2000), and the anti-inflammatory activity of an iridoid glucoside isolated from the plant (Suksamran et al. 1986) have been
Anti-diabetic potential of Barleria lupulina extract in rats published, and no other information on its pharmacological properties have yet appeared. Some other species of Barleria have been tested for their hypoglycemic potential and found to be active of B. cristata, B. prionitis; Dhar et al. 1968; Bhakuni et al. 1969; Dhawan et al. 1977; Rahman and Zaman, 1989). These reports justify our interest in further studies of this plant. The pharmacological activities of this plant extract are currently being studied in our laboratory. In the study reported here, we have evaluated the glucose-lowering effect of a methanol extract of the aerial parts of Barleria lupulina (MEBL) in streptozotocin hyperglycemic rats, to establish pharmacological evidence in support of the folkloric claim of anti-diabetic activity.
Materials and Methods Plant material
Aerial parts of Barleria lupulina (Acanthaceae) were collected during the winter season (October-December) from Jhilimili, Bankura district, West Bengal, India, and authentication of the plant specimen was established by the Botanical Survey of India, Shibpur, Howrah. The voucher specimen (No: CNH/I-I (52), 2000-Tech.II) has been deposited in our departmental herbarium for future reference. Extraction procedure
The aerial parts were dried and pulverized to a coarse powder. The powder was passed through a 40-mesh sieve and extracted exhaustively with 90% v/v methanol in a Soxhlet apparatus. The extract was evaporated in vacuo until all the solvent had been removed, to yield an extract sample a 10. 8% w/w. The chemical make-up of the extract was analyzed using a qualitative test and found to contain flavonoids, steroids and tannins. These were confirmed by the tic study (hRf values). The extract was stored in the refrigerator and a weighed amount was prepared in propylene glycol for the present investigation. Test animals
Male Wistar rats weighing between 150–200 g each were used for the investigation. The animals were housed at a temperature of 21 ± 20 °C, with humidity of 55 ± 10% and a 12-h light-dark cycle (lights on at 0600 h). Rats were supplied with a standard pellet diet and tap water was freely available. Toxocological study
The determination of LD50 values of the methanolic extract of Barleria lupulina was performed in albino mice following the method of Ghosh (1984).
203
Blood collection
Blood samples were collected in heparinized tubes from the tail veins of the rats and plasma was separated within 30 min of withdrawal, for the determination of glucose concentration. Effect of extract in streptozotocin-hyperglycemic rats
Groups of rats, fasted for 18 h, were made hyperglycemic by intraperitoneal injection of streptozotocin (Sigma USA) dissolved in citrate buffer (pH 4.3), at a dose of 50 mg/kg–1 body wt. After 48 h, their plasma glucose levels were estimated and moderately streptozotocin-hyperglycemic rats (Chattopadhyay, 1993), having plasma glucose levels above 250 mg (%) were selected and divided into groups of 6 animals each. One group received glibenclamide (10 mg/kg body wt., p.o) and a control group received propylene glycol (10 ml/kg body wt.). Other groups were administered MEBL at oral doses of 100, 200 and 300 mg/kg body wt. (i.p). Blood glucose concentrations were measured at 0, 4, 8 and 12 h after drug treatment by the orthotoluidine method (Hultman, 1995; Hyavariner et al. 1962). Statistical analysis
The data are represented as Mean ± S. E. M., and statistical significance between treated and control groups was analyzed using of ANOVA, followed by Dunnet’s t-test. (Woodson, 1987).
Result and Discussion Toxicity study
On the basis of the toxicity study, the LD50 value of the plant extract in mice was 4.5 g/kg body wt. (p.o) and 3.7 g/kg body wt. (i.p). The extract (MEBL) exhibited significant (p < 0.01) anti-hyperglycemic efficacy from 4 h after its oral administration at all doses tested, when compared control group values, and the effect was prolonged up to 12 h. The extract at doses of 200 mg/kg body wt. and above shwed maximum activity (p < 0.001) at 12 h after administration. The high percentage (15.35%) of blood-glucose-lowering potential was observed in the group administered with 300 mg/kg body wt. extract at 12 h after administration, while the standard drug, glibenclamide (10 mg/kg body wt.) caused an 18.80% reduction in blood glucose level at the same time interval (Table 1). The methanol extract of the aerial parts of Barleria lupulina was also tested for its hypoglycemic effect in normal rat,s and was found to have no influence on normal glucose concentration (data not reported).
204
V. Suba et al.
Table 1. Anti-diabetic activity of Barleria lupulina extract in streptozotocin-hyperglycemic rats. Treatment and dose
Plasma glucose concentration in mg% Time after treatment (in h) 0
4
8
12
Control 10 ml/kg1 body wt.
272.50 ± 1.11
271.66 ± 1.05
268.33 ± 3.80
265.83 ± 5.00
MEBL 100 mg/kg body wt.
269.16 ± 1.02
254.83 ± 1.25* (6.19)
253.33 ± 2.45* (5.59)
240.83 ± 3.75** (9.40)
MEBL 200 mg/kg body wt.
265.00 ± 2.47
252.50 ± 3.04* (7.05)
245.83 ± 2.45** (8.38)
230.00 ± 1.70** (13.47)
MEBL 300 mg/kg body wt.
265.00 ± 1.63
251.66 ± 4.47* (7.36)
240.00 ± 3.75** (10.55)
225.00 ± 4.60** (15.35)
Glibenclamide 10 mg/kg body wt.
265.00 ± 2.62
242.50 ± 2.45** (10.73)
238.33 ± 4.83** (11.18)
215.84 ± 3.75** (18.80)
Each value represents Mean ± S.E.M. (n = 6). * – p < 0.01, ** – p < 0.001,versus control (Propylene glycol). Figure in the parenthesis denotes percentage of reduction (plasma glucose). MEBL – Methanol extract of aerial parts of Barleria lupulina.
Discussion
From the present experimental results it can be suggested that the extract acts in a fashion similar to glibenclamide, the standard anti-diabetic drug. This similarity to glibenclamide will be a subject of further invistigations. Glilbenclamide and a natural hypoglycemic product have been reported to be effective in moderately streptozotocin-diabetic animals and ineffective in severely diabetic rats (Ivorra et al. 1988; Sharma et al. 1997). Phytochemical analysis showed that the major chemical constituents of the extract (MEBL) were flavonoids, steroids and tannins. Over 150 plant extracts and some of their active principles, including flavonoids, are known for the treatment of diabetes (Choi et al. 1991; Erenmemisoglu et al. 1995; Meiselman et al. 1976). Moreover, tannin-containing drugs demonstrated anti-diabetic activity (Iwu, 1980; Iwu, 1983). In our study we have also isolated the flavonoid quercetin from the plant extract. On the basis of previous reports, it is possible that the presence of flavonoids is responsible for the observed anti-diabetic activity.
Reference Akhtar FM, Ali MR (1980) Study of the anti-diabetic effect of a compound medicinal plant prescription in normal and diabetic rabbit. J Pakistan Med Assoc 34: 239–244
Anonymous (1966) The Wealth of India. Vol I. Publication and Information Directorate, CSIR, New Delhi, p 175 Bhakuni OS, Dhar ML, Dhar MM, Dhawan BN, Mehrotra BN (1969) Screen of Indian Plants for Biological Activity. Part II. Indian J Exp Biol 7: 250–262 Byrne LT, Sasse JM, Skelton BW, Suksamran A, White AH (1987) The minor iridoid glycosides of Barleria lupulina isolation, crystal structure and plant growth-inhibiting properties of 6-o-Acetylshanzhiside methyl ester. Aust J Chem 40: 785–794 Chattopadhya RR (1993) Hypoglycemic effect of Ocimum sanctum leaf in normal and streptozotocin diabeic rats. Indian J Exp Biol 31: 891–893 Chopra RN, Nayar SL, Chopra IC (1968) Glossary of Indian Medicinal Plants. Academic Publishers, New Delhi, India; pp 20 Choi JS, Yokozawa T, Oura H (1991) Improvement of hyperglycemia and methanolic extract of Prunus davidana stems and its main component, prurin. Planta Med 57: 208–211 Dhar ML, Dhar MM, Dhawan N, Mehrotra BN, Ray C (1968). Screening of Indian Plants for Biological Activity: Part I. Indian J Exp Biol 6: 232–247 Dhawan BN, Patnaik GK, Rastogi RP, Singh KK, Tandon JS (1977) Screening of Indian Plants for Biological Activity, VI. Indian J Exp Biol 15: 208–219 Erenmemisoglu A, Kelestimur F, Koker AH, Ustun H, Tekol Y, Ustdal M (1995) Hypoglycaemic effect of Zizyphus jujuba leaves. J Pharm Pharmacol 47: 72–74 Ghosh MN (1984). Fundamental of Experimental Pharmacology, 2nd Edn. Scientific Book Agency, Calcutta, India. pp 153
Anti-diabetic potential of Barleria lupulina extract in rats Hultman E (1959) Rapid specific method for determination of aldo saccharides in body fluids. Nature 183: 108–109 Hyavariner A, Nikkita E (1962) Specific determination of Blood glucose with ortho toluidine. Clin Chim Acta 7: 140–143 Ivorra MD, Paya M, Villar A (1988) Hypoglycemic and insulin release effects of tormentic acid: a new hypoglycemic natural product. Planta Med 54: 282–285 Iwu MM (1983) Hypoglycemic properties of Bridelia ferruginea leaves. Fitoterapia 54: 243–248 Iwu MM (1980) Antidiabetic properties of Bridelia ferruginea leaves. Planta Med 39: 247 Kanchanapoom T, Kasai R, Yamasaki K (2001) Iridoid Glucosides from Barleria lupulina. Phytochemistry 58: 337–341 Larner J (1985). Insulin and oral hypoglycemic drug, Glucogan. In: Gilman AG, Goodman LS, Rall IW, Murad F (Eds). The Pharmacological basis of Therapeutics, 7th edition, Macmillan, NewYork, pp 1490–1516 Meiselman HL, Halpern BP, Dateo GP (1976). Reduction of sweetness judgements by extracts from the leaves of Zizyphus jujuba. Physiol Behav 17: 313–317 Rahman Q-U, Zaman K (1989). Medicinal plants with hypoglycemic activity. J Ethnopharmacol 26: 1–55 Sharma SR, Dwivedi SK, Swarup D (1997) Hypoglycemic, antihyperglycemic, hypolipidemic activities of Caesalpinia bonducella seeds in rats. J Ethnopharmacol 58: 39–44
205
Suksamran A (1986) Iridoid glucosides from Barleria lupulina. J Nat Prod 49: 179 The WHO Expert Committee on Diabetes Mellitus, Technical Report Series World Health Organization, Geneva. 1980 Tuntiwachwuttikul P, Pandiaroen O, Taylor WC (1998) Iridoid glucosides of Barleria lupulina. Phytochemistry 49: 163–166 Woodson RF (1987) Statistical Methods for the Analysis of Biomedical Data, Wiley Series in Probability and Mathematical Statistics. Wiley, Chichester. Pp 315–316, Yoosook C, Panpisutchai Y, Chaichana S, Santisuk T, Reutrakul V (1999) Evaluation of Anti-HSV-2 activities of Barleria lupulina and Clicanthus nutans. J Ethnopharmacol 67: 179–187 Yoosook C, Bunyapraphatsara N, Boonyakiat Y, Kantasuk C (2000) Anti-Herpes simplex virus activities of crude water extracts of Thai medicinal plants. Phytomedicine 6: 411–419
Address B. P. Saha, Department of Pharmaceutical Technology, Jadavpur University, Calcutta - 700 032, India Tel.: 033-2413-6303; Fax: 91-33-23357254; e-mail: [email protected], [email protected]