Amirin Sadikun

Studies on diuretic and hypouricemic effects of Orthosiphon stamineus methanol extracts in rats

AIM OF THE STUDY Orthosiphon stamineus (Labiatae) is a traditional folk medicine widely used in Southeast Asia for the treatment of several kidney disorders, gout and as a diuretic. This study was conducted to examine the diuretic and hypouricemic effects of Orthosiphon stamineus leaf extracts. MATERIALS AND METHODS The diuretic effect of different methanol extracts was examined by treating different groups of Sprague-Dawley rats with single (2g/kg) oral doses of methanol and methanol:water (1:1) extracts. Hydrochlorothiazide (10mg/kg) was used as positive control in acute study. Methanol and methanol water (1:1) extracts at 0.5 g/kg were administered for a period of 7 consecutive days. Cumulative urine volume and electrolytes (Na+ and K+) concentrations at different time intervals were measured. On the other hand, hypouricemic activity of methanol:water extract (1:1) was experimented using different oral single doses (0.25, 0.5, 1 and 2g/kg). Allopurinol was used as positive control. Uric acid concentration in serum was analyzed by using RP-HPLC at 280 nm. RESULTS Sodium and potassium excretion increased significantly (p<0.05 and <0.01) in the first 8h of treatment with a single dose (2g/kg) of the extracts in a pattern comparable to that of the known diuretic hydrochlorothiazide. Meanwhile, repeated administration of 0.5 g/kg methanol:water (1:1) extract showed a significant increase in urine volume (from day 3 to day 7) (p<0.01) and electrolytes excretion (Na+ and K+) from day 2 to day 7 (p<0.05 and <0.01). On the other hand, 0.5, 1 and 2g/kg of methanol:water (1:1) extract and the standard allopurinol reduced the serum urate level in hyperuricemic rats at hour 6. CONCLUSION These results provided an evidence of the high tendency of methanol:water (1:1) extract of Orthosiphon stamineus towards diuretic and hypouricemic effects in rats.

Toxicity evaluation of a standardised 50% ethanol extract of Orthosiphon stamineus.

AIM OF THE STUDY The present investigation was carried out to evaluate the safety of standardised 50% ethanol extract of Orthosiphon stamineus plant by determining its potential toxicity after acute and subchronic administration in rats. MATERIALS AND METHODS For acute toxicity study, up and down method (limit dose) was adapted. A single dose of 5000 mg/kg of the standardised 50% ethanol extract of O. stamineus was given orally to 5 healthy Sprague-Dawley (SD) female adult rats. The rats were observed for mortality and clinical signs for 3 h and then periodically for 14 days. While in the subchronic toxicity study, the extract was administered orally at doses of 1250, 2500 and 5000 mg/kg per day for 28 days to female and male SD rats, respectively. The animals were sacrificed, followed by examination of their organs and blood serum. RESULTS In the acute toxicity study, standardised 50% ethanol extract of O. stamineus at a dose of 5000 mg/kg caused neither visible signs of toxicity nor mortality. All five rats survived until the end of observation period. While in subchronic toxicity, administration of the standardised 50% ethanol extract of O. stamineus at 1250, 2500, and 5000 mg/kg for 28 days did not produce any mortality and there were no significant differences in the general condition, growth, organ weights, hematological parameters, clinical chemistry values, or gross and microscopic appearance of the organs from the treatment groups as compared to the control group. CONCLUSIONS Standardised 50% ethanol extract of O. stamineus did not cause any death nor did it cause abnormalities in necropsy and histopathology findings. There were no acute or subchronic toxicity observed and this extract could be devoid of any toxic risk. The NOAEL for the standardised 50% ethanol extract of O. stamineus is 5000 mg/kg per day for 28 days.

Flavonoid Identification and Hypoglycaemic Studies of the Butanol Fraction from Gynura procumbens

The methanol extract of the leaves of Gynura procumbens was partitioned between chloroform, ethyl acetate and n -butanol. Qualitative HPLC identification of the major flavonoid constituents in the n -butanol fraction and separation of standard mixture of isolated compounds from the n -butanol fraction are given. Blood glucose levels in streptozotocin-induced type 2 diabetic rats were reduced by the administration of 1 g/kg of the n -butanol fraction. The results were compared with glibenclamide used as standard drug. The fraction produced no significant effect in normal rats.

Potent α-glucosidase and α-amylase inhibitory activities of standardized 50% ethanolic extracts and sinensetin from Orthosiphon stamineus Benth as anti-diabetic mechanism

BackgroundIn the present study, we tested a 50% ethanolic extract of Orthosiphon stamineus plants and its isolated bioactive compound with respect to their α-glucosidase and α-amylase inhibitory activities.MethodsBioactive flavonoid sinensetin was isolated from 50% ethanolic extract of Orthosiphon stamineus. The structure of this pure compound was determined on the NMR data and the α-glucosidase and α-amylase inhibitory activities of isolated sinensetin and 50% ethanolic extract of Orthosiphon stamineus were evaluated.ResultsIn vitro studies of a 50% ethanolic extract of O. stamineus and the isolated sinensetin compound showed inhibitory activity on α-glucosidase (IC50: 4.63 and 0.66 mg/ml, respectively) and α-amylase (IC50: 36.70 mg/ml and 1.13 mg/ml, respectively). Inhibition of these enzymes provides a strong biochemical basis for the management of type 2 diabetes via the control of glucose absorption.ConclusionAlpha-glucosidase and α-amylase inhibition could the mechanisms through which the 50% ethanolic extract of O. stamineus and sinensetin exert their antidiabetic activity, indicating that it could have potential use in the management of non-insulin-dependent diabetes.

HPLC and Anti-Inflammatory Studies of the Flavonoid Rich Chloroform Extract Fraction of Orthosiphon Stamineus Leaves

The aim of the present study was to verify the anti-inflammatory activity of Orthosiphon stamineus leaf extracts and to identify the active compound(s) contributing to its anti-inflammatory activity using a developed HPLC method. Active chloroform extract of O. stamineus was fractionated into three fractions using a dry flash column chromatography method. These three fractions were investigated for anti-peritoneal capillary permeability, in vitro nitric oxide scavenging activity, anti-inflammatory and nitric oxide (NO) inhibition using carrageenan-induced hind paw edema method. The flavonoid rich chloroform extract fraction (CF2) [containing sinensetin (2.86% w/w), eupatorin (5.05% w/w) and 3’-hydroxy-5,6,7,4’-tetramethoxyflavone (1.101% w/w)], significantly reduced rat hind paw edema, NO and decreased dye leakage to peritoneal cavity at p < 0.05. IC50 of in vitro NO scavenging of CF2 was 0.3 mg/mL. These results suggest that the anti-inflammatory properties of these CF2 may possibly be due to the presence of flavonoid compounds capable of affecting the NO pathway.

Hypoglycemic and anti–hyperglycemic study of Gynura procumbens leaf extracts

OBJECTIVE To study the antidiabetic activity of Gynura procumbens (G. procumbens) used in the traditional management of diabetes in Southern Asia. METHODS G. procumbens leaves were extracted sequentially with graded percentage of ethanol in water (95%, 75%, 50%, 25% and 0%), and the extracts were tested for antidiabetic activity using acute (7 h), subcutaneous glucose tolerance test and sub-chronic (14 d) test in non-diabetic and streptozotocin-induced diabetic rats. The extracts were further subjected to phytochemical studies. RESULTS In acute dose (1 g/kg), the extracts significantly lowered fasting blood glucose (FBG) in streptozotocin-induced diabetic rats (P<0.05). However, the FBG-lowering effect of the 25% extract compared to the other extracts, was rapid (47% after 2 h) and the highest: 53%, 53% and 60% in the 3rd, 5th, and 7th h, respectively (P<0.05), comparable only to the effect of metformin. Furthermore, the extracts suppressed peak FBG in subcutaneous glucose tolerance test, but only the 0% and 25% extracts, and metformin sustained the decrease until the 90th min (P<0.05). Moreover, in the 14 days study, the 25% extract exerted the highest FBG-lowering effect, namely 49.38% and 65.43% on days 7 and 14, respectively (P<0.05), similar to the effect of metformin (46.26% and 65.42%). Total flavanoid and phenolic contents in the extracts were found to decrease with increase in polarity of extraction solvents. The composition of reference compounds (chlorogenic acid, rutin, astragalin and kaempferol-3-O-rutinoside) followed a similar trend. CONCLUSIONS G. procumbens contains antidiabetic principles, most extracted in 25% ethanol. Interaction among active components appears to determine the antidiabetic efficacy, achieved likely by a metformin-like mechanism.

A bitter plant with a sweet future? A comprehensive review of an oriental medicinal plant: Andrographis paniculata

Andrographis paniculata (Burm.f) Nees is one of the most popular and important medicinal plant of the Orient, and South East Asia. It finds mention in various forms in Indian, Chinese, Malay, Thai, Unani, and Japanese systems of medicine. The plant exhibits anti-cancer, anti-inflammatory, anti-diabetic, anti-hypertensive, anti-venom, cholestatic, hepatoprotective, anti-thrombotic, anti-retroviral, anti-microbial, anti-pyretic, anti-malarial, anti-oxidant, immunomodulatory, and cardioprotective effects. The major active principles contributing to biological activity are diterpene lactones, but flavonoids, xanthones and caffeic acid derivatives also contribute to anti-oxidant, anti-proliferative, anti-atherosclerotic, and anti-malarial effects. As a result of its wide spectrum of pharmacological activity, almost impeccable safety profile, being a widely cultivated medicinal plant, we have collected and compiled various facets of this plant. Extensive datamining of the phytochemistry and pharmacology of Andrographis paniculata revealed more than 50 diterpene lactones, 30 flavonoids, 8 quinic acid derivatives, and 4 xanthones. This review contains information on around 80 isolated compounds, out of which more than half of the compounds have no reported pharmacological activity. Though there are some good reviews available on Andrographis paniculata, the authors of the earlier reviews focused on one or two aspects of the plant and none have attempted to integrate the available information on this plant. This provided us the much needed impetus, warranting a full-fledged and complete review on Andrographis paniculata, one of the most popular and important Oriental medicinal plant.

Phytochemistry and medicinal properties of Phaleria macrocarpa (Scheff.) Boerl. extracts

Phaleria macrocarpa, commonly known as Mahkota dewa is a medicinal plant that is indigenous to Indonesia and Malaysia. Extracts of P. macrocarpa have been used since years in traditional medicine that are evaluated scientifically as well. The extracts are reported for a number of valuable medicinal properties such as anti-cancer, anti-diabetic, anti-hyperlipidemic, anti-inflammatory, anti-bacterial, anti-fungal, anti-oxidant and vasorelaxant effect. The constituents isolated from different parts of P. macrocarpa include Phalerin, gallic acid, Icaricide C, magniferin, mahkoside A, dodecanoic acid, palmitic acid, des-acetylflavicordin-A, flavicordin-A, flavicordin-D, flavicordin-A glucoside, ethyl stearate, lignans, alkaloids andsaponins. The present review is an up-to-date summary of occurrence, botanical description, ethnopharmacology, bioactivity and toxicological studies related to P. macrocarpa.

Antihyperglycemic effect of orthosiphon stamineus benth leaves extract and its bioassay-guided fractions.

Preliminary investigations were carried out to evaluate the antidiabetic effects of the leaves of O. stamineus extracted serially with solvents of increasing polarity (petroleum ether, chloroform, methanol and water); bioassay-guided purification of plant extracts using the subcutaneous glucose tolerance test (SbGTT) was also carried out. Only the chloroform extract, given at 1 g/kg body weight (b.w.), significantly reduced (P < 0.05) the blood glucose level of rats loaded subcutaneously with 150 mg/kg (b.w.) glucose. The active chloroform extract of O. stamineus was separated into five fractions using a dry flash column chromatography method. Out of the five fractions tested, only chloroform fraction 2 (Cƒ2), at the dose of 1 g/kg (b.w.) significantly inhibited (P < 0.05) blood glucose levels in SbGTT. Active Cƒ2 was split into two sub-fractions Cƒ2-A and Cƒ2-B, using a dry flash column chromatography method. The activities Cƒ2-A and Cƒ2-B were investigated using SbGTT, and the active sub-fraction was then further studied for anti-diabetic effects in a streptozotocin-induced diabetic rat model. The results clearly indicate that Cƒ2-B fraction exhibited a blood glucose lowering effect in fasted treated normal rats after glucose-loading of 150 mg/kg (b.w.). In the acute streptozotocin-induced diabetic rat model, Cƒ2-B did not exhibit a hypoglycemic effect on blood glucose levels up to 7 hours after treatment. Thus, it appears that Cƒ2-B functions similarly to metformin, which has no hypoglycemic effect but demonstrates an antihyperglycemic effect only in normogycemic models. The effect of Cƒ2-B may have no direct stimulatory effects on insulin secretion or on blood glucose levels in diabetic animal models. Verification of the active compound(s) within the active fraction (Cƒ2-B) indicated the presence of terpenoids and, flavonoids, including sinensitin.

Pharmacological mechanisms underlying the vascular activities of Loranthus ferrugineus Roxb. in rat thoracic aorta.

AIM OF THE STUDY The present study was aimed to investigate the pharmacological basis for the use of Loranthus ferrugineus in hypertension. MATERIALS AND METHODS Loranthus ferrugineus methanol extract (LFME) was obtained using Soxhelt extractor and then successively fractionated using chloroform, ethyl acetate and n-butanol. The n-butanol fraction of LFME (NBF-LFME) was studied using isolated rat thoracic aorta. RESULTS NBF-LFME (1.0 x 10(-5) to 3.0mg/ml) was found to be the most potent to concentration-dependently relax the endothelium-intact phenyephrine (PE, 1 microM)- and high K(+) (80 mM)-precontracted rat aortic rings. Removal of the endothelium completely abolished the vascular relaxing properties of NBF-LFME. Pretreatment with atropine (1 microM), L-NAME (10 microM), indomethacin (10 microM) and methylene blue (10 microM) significantly blocked NBF-LFME-mediated relaxation. Endothelium-dependent and -independent relaxations induced by acetylcholine (ACh) and sodium nitroprusside (SNP), respectively, were significantly enhanced in aortic rings pretreated with NBF-LFME when compared to those observed in control aortic rings. On the contrary, glibenclamide (10 microM), propranolol (1 microM) and prazosin (0.01 microM) did not alter NBF-LFME-induced relaxation. CONCLUSIONS The results suggest that NBF-LFME induced vascular relaxation by stimulating muscarinic receptors, activating the endothelium-derived nitric oxide-cGMP-relaxant pathway, promoting prostacyclin release and/or possibly through its ability to lengthen the released nitric oxide half-life. The present data further supports previous in vivo findings and explain the traditional use of Loranthus ferrugineus as an anti-hypertensive agent.