Diabetic nephropathy is a serious microvascular complication and one of the main causes of endstage renal disease. L-Glutamine (LG) is naturally occurring amino acids with antidiabetic and antioxidant potential. The aim of present investigation was to evaluate the potential of LG against streptozotocin (STZ)-induced diabetic nephropathy (DN) in laboratory rats. DN was induced in male Wistar rats (200-220 g) by intraperitoneal administration of STZ (55 mg/kg). Animals were treated orally with either distilled water (10 mg/kg) or LG (250, 500, and 1000 mg/kg) or Sitagliptin (5 mg/kg). Various biochemical, molecular, and histological (hematoxylin-eosin and Masson's trichrome stain) parameters were assessed. Administration of LG (500 and 1000 mg/kg) significantly inhibited (p < .05) STZ-induced alterations in serum and urine biochemistry (urine creatinine, uric acid, albumin, and BUN). It also significantly increased creatinine clearance rate. STZ induced increase in renal oxidonitrosative stress was significantly decreased (p < .05) by LG (500 and 1000 mg/kg) treatment. Upregulated renal KIM-1, NGAL, TGF-b1, and collagen-1 mRNA expression after STZ administration was significantly inhibited (p < .05) by LG (500 and 1000 mg/ kg) treatment. Correlation analysis also revealed that antidiabetic potential of LG attenuates STZinduced elevated renal KIM-1, NGAL, TGF-b1, and collagen-1 mRNA expression. Histopathological alteration induced by STZ in renal tissue was ameliorated by LG treatment. In conclusion, results of present investigation suggest that treatment with LG ameliorated STZ-induced DN via the inhibition of oxidonitrosative stress as well as downregulation of KIM-1, NGAL, TGF-b1, and collagen-1 mRNA expressions. ARTICLE HISTORY

Adhatoda vasica (L.) Nees (family Acanthaceae) is a shrub 1 2.5 m high with opposite ascending branches simple, opposite, 7-19 cm long and 4-7 cm wide. The are white, pink or purple. The plant grows throughout the Indian peninsula up to an altitude of 1300m. The names Adhatoda zeylanica Medic and Justicia adhatoda L. are used synonymously. It is also known under the common name Malabar nut tree and the Sanskrit name Vasaka. The plant has been used in the indigenous system of medicine in India for over 2000 years. It is a well-known drug in Ayurvedic and Unani medicine (Manjunath, 1948). The leaves was used for stomach catarrh with constipation, gout, urinary stone (Madaus, 1938) and warmed leaves used externally for rheumatic pains and dislocation of joint (Rao and Jamir, 1982). Anti-oxidant and radical scavenging activity (Srinivasarao et al., 2006) Anti-inflammatory effect et al., 2011