Direct somatic embryogenesis of Malaxis densiflora (A. Rich.) Kuntze.

A protocol for induction of direct somatic embryogenesis and subsequent plant regeneration for the medicinally important and endangered plant of Malaxis densiflora has been developed for the first time. In the present study, in vitro seed derived protocorm explants were cultured on half strength Murashige and Skoog (MS) medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D), Picloram and Dicamba individually and in combination with cytokinins BAP, TDZ and Kn for its effectiveness to induce the differentiation of somatic embryos. The best response was observed in protocorms cultured half strength MS medium supplemented with 2,4-D at 3.39 µM and TDZ at 6.80 µM. Both epidermal and sub epidermal cells were involved in the formation of embryos. The proembryos developed into globular stage and subsequently developed into protocoms. Complete plantlets were formed after 60 days of culture. The plantlets were acclimatized in plastic pots containing sterilized vermiculite. The survival rate was 76%.

In vivo anti-diabetic, antioxidant and molecular docking studies of 1, 2, 8-trihydroxy-6-methoxy xanthone and 1, 2-dihydroxy-6-methoxyxanthone-8-O-ß-D-xylopyranosyl isolated from Swertia corymbosa.

1, 2, 8-trihydroxy-6-methoxy xanthone (1) and 1, 2- dihydroxy-6-methoxyxanthone-8-O-ß-d-xylopyranosyl (2) are the main constituents of petroleum ether and ethyl acetate extracts from Swertia corymbosa (Gentinaceae), a medicinal plant used in Indian traditional system for the treatment of diabetes. The present study was designed to examine the antihypoglycemic, antihyperlipidemic and antioxidant effect of compounds 1 and 2 in streptozotocin (STZ) induced diabetic rats. Diabetes was induced in male Wistar rats by a single intraperitoneal injection of STZ (60 mg/kg b.w.). The isolated compounds 1 and 2 at a dose of 50 mg/kg b.w., produced the maximum fall of 83% in the blood glucose level in the diabetic rats after 3h of the treatment. The administration of 1 and 2 (50 mg/kgb.w.) daily for 28 days in STZ induced diabetic rats, resulted in a significant decrease in blood glucose, glycosylated hemoglobin, SGOT, SGPT, ALP serum urea and creatinine with significant rise in plasma insulin level. Test compounds 1 and 2 showed antihyperlipidemic activities as evidenced by significant decrease in serum TC, TG, LDL-C, VLDL-C levels coupled together with elevation of HDL-C level in diabetic treated rats when compared to diabetic untreated rats, indicate the protective role against liver and kidney damage. The results of histopathology also showed 1 and 2 protected tissues (pancreas, liver and kidney) against peroxidation damage and maintained tissue integrity. Further, the molecular interaction study of the ligands 1, 2 and glibenclamide with various diabetes mellitus related protein targets like glucokinase (PDB ID: 1V4S), fructose-1, 6-bisphosphatase 1 (PDB ID: 2JJK) 11-ß-hydroxysteroid dehydrogenase (PDB ID: 2BEL) and modeled protein sulfonylurea receptor 1 (SUR1) showed that ligand 1 and 2 possess binding affinity with all protein targets except for 2BEL target protein for which ligand 1 has no interaction. The ligand pose with 2BEL and SUR1 protein target of ligand 2 gave the best binding conformation. Hence 1 and 2 can be considered for developing into a potent antidiabetic drug.

RETRACTED: Anti-diabetic activity of Swertia corymbosa (Griseb.) Wight ex C.B. Clarke aerial parts extract in streptozotocin induced diabetic rats.

ETHNOPHARMACOLOGICALS RELEVANCE: Swertia corymbosa locally called as Shirattakuchi have a long history of use in Ayurveda herbal preparations in Indian traditional system of medicine. It has been used in folklore medicine for the treatment of diabetes. AIM OF THE STUDY: The present study aimed to investigate the effect of the methanolic extract of Swertia corymbosa (SC) in diabetic and to analyze its chemical composition by HPLC-ESI/MS that may correlate with their pharmacological activities. MATERIALS AND METHODS: The in vitro anti-diabetic activity of the extracts was measured by using α-glucosidase and α-amylase enzyme inhibitory activity. The methanolic extract of Swertia corymbosa were administered orally (125, 250 and 500 mg/kg, for 28 days) to streptozotocin-induced diabetic rats. Hypoglycemic effects, oral glucose tolerance test, change in body weight and lipid profile, biochemical analysis and histopathological examination were assessed. High-performance liquid chromatography-electrospray ionization/mass spectrometry (HPLC-ESI/MS) method was also developed to analyze the chemical composition. RESULTS: In vitro anti-dabetic study, the methanol extract of SC is found to be a potent inhibitor of α-glucosidase and α-amylase activity. Oral administration of SC and standard drug for 28 days caused a significant decrease in the concentrations of blood glucose level, total cholesterol (TC), serum triglycerides (TGs), low-density lipoprotein-cholesterol (LDL-C), malondialdehyde (MDA) and significant increase in the concentrations of high density lipoprotein-cholesterol (HDL-C), serum insulin and body weight. Furthermore, activities of antioxidative enzymes, including SOD, GPx, GSH and CAT were enhanced dosed dependently with SC. Histopathological studies of the pancreas showed the regeneration of the ß-cells by extract which were earlier necrosed by streptozotocin. Ten major compounds such as loganic acid (1), swertiamarin (2), sweroside (3), gentiopicroside (4), isovitexin (5), amoroswertin (6), amarogentin (7), gentiacaulein (8), decussatin (9) and swertianin (10) were analyzed by HPLC-ESI/MS system. CONCLUSIONS: These results demonstrate that SC aerial parts of methanolic extract is an effective anti-diabetic and antioxidant activities which provides the scientific proof for the folklore medicine.

Antiacetylcholinesterase and antioxidant ent-Kaurene diterpenoid, melissoidesin from Isodon wightii (Bentham) H. Hara.

The ent kaurene diterpenoid, melissoidesin was isolated from the acetone extract of the leaves of Isodon wightii and the structure was designated as 3beta, 11beta, 15beta-trihydroxy-6alpha-acetoxy-ent-kaur-16-ene based on spectral data and previous reports. Melissoidesin isolated from the acetone extract of leaves showed potent antiacetylcholinesterase activity and the IC(50) value was observed as 215 microg mL(-1). DPPH (1, 1-diphenyl-2-picrylhydrazyl) free radical scavenging activity of melissoidesin was significant and the IC(50) value was 138 microg mL(-1). The significant reducing property of the melissoidesin was stronger in high concentration. IC(50) value of melissoidesin on hydroxyl radicals and metal chelation was observed as 99 and 143 microg mL(-1), respectively. The 50% inhibitory concentration of melissoidesin on lipid peroxidation was calculated as 133 microg mL(-1). These findings indicate that ent kaurene diterpenoid, melissoidesin was promising antiacetylcholinesterase and antioxidant which can be used as food and drug preparations.

Antifungal properties of Pseudarthria viscida.

The extracts of leaf, root, stem, and the callus obtained from Pseudarthria viscida showed significant inhibitory activity against some fungal pathogens causing major diseases in crop plants and stored food grains.

Antibacterial activity of Salacia beddomei.

Leaves and stems of Salacia beddomei were extracted successively with petroleum ether, ethyl acetate and chloroform and tested for their antibacterial activity. Ethyl acetate extracts were found to be most effective against all the tested organisms.

Modulatory effects of Gymnema montanum leaf extract on alloxan-induced oxidative stress in Wistar rats.

OBJECTIVES: In light of evidence that some complications of diabetes mellitus may be caused or exacerbated by oxidative damage, we investigated the effect of Gymnema montanum leaf extract (GLEt) on tissue antioxidant defense systems in alloxan-induced diabetes in rats. METHODS: GLEt was administered orally at a doses of 50, 100, and 200 mg/kg of body weight for 30 d, after which liver and kidney tissues were assayed for the degree of lipid peroxidation by means of markers, reduced glutathione content and activities of catalase, superoxide dismutase, glutathione peroxidase, and glutathione-S-transferase. RESULTS: Treatment of diabetic rats with GLEt increased the antioxidant levels. Liver and kidney from diabetic animals exhibited disturbances in antioxidant defense when compared with normal rats. GLEt at a dose of 200 mg/kg of body weight exhibited a significant effect as compared with 50 and 100 mg/kg of body weight. These effects were compared with glibenclamide, a reference drug. CONCLUSIONS: It may be concluded that, in diabetes, liver and kidney tissues are more vulnerable to oxidative stress and show increased lipid peroxidation. The antioxidant responsiveness mediated by G. montanum may be anticipated to have biological significance in eliminating reactive free radicals that may otherwise affect normal cell functioning and provide a scientific rationale for the use of G. montanum as an antidiabetic plant.

Effect of Gymnema montanum leaves on serum and tissue lipids in alloxan diabetic rats.

The effect of Gymnema montanum leaves on alloxan-induced hyperlipidemia was studied in male Wistar rats. Ethanolic extract of G. montanum leaves was administered orally and different doses of the extract on blood glucose, serum and tissue lipids, hexokinase, glucose-6-phosphatase, thiobarbituric acid-reactive substances (TBARS), hydroperoxides, and glutathione in alloxan-induced diabetic rats were studied. G. montanum leaf extract (GLEt) at doses of 50, 100, 200 mg/kg body weight for 3 weeks suppressed the elevated blood glucose and lipid levels in diabetic rats. GLEt at 200 mg/kg body weight was found to be comparable to glibenclamide, a reference drug. These data indicate that G. montanum represents an effective antihyperglycemic and antihyperlipidemic adjunct for the treatment of diabetes and a potential source of discovery of new orally active agent for future therapy.