Synthesis of aminomethyl linked (+)-usnic acid derivatives via the Mannich reaction and evaluation of their biological activities.

(+)-Usnic acid (UA), a natural dibenzofuran derivative, abundantly produced by lichens and possess wide number of biomedical applications including antibacterial, anti-inflammatory, anti-oxidant and anticancer activities. In the present study, as series of usnic acid derivatives (3a-3i) were synthesised using Mannich reaction assessed for their antioxidant, α-glucosidase, and anticancer activities. The in vitro antioxidant activity showed that compound 3d displayed potent antioxidant activity by scavenging the activities of DPPH and ABTS+. The compounds 3d and 3e showed potent cytotoxic activity against HepG2 cancer cells by arresting the cell cycle at S phase and regulating the Bax/BcL2 expression and subsequently induce the apoptosis. Overall, the results clearly indicated that (+)-usnic acid derivatives bearing secondary amines are useful scaffolds for the development of drug candidates for treatment of oxidative stress mediated cancer and metabolic disorders.

Bombax ceiba calyx displays antihyperglycemic activity via improving insulin secretion and sensitivity: Identification of bioactive phytometabolomes by UPLC-QTof-MS/MS.

Vegetables are considered good food for the management of hyperglycemia. Bombax ceiba L. (family: Bombacaceae) calyces are part of traditional vegetables. This study evaluated its usefulness on various parameters responsible for the development of hyperglycemia and conducted phytometabolomic analysis to identify phytochemicals responsible for the observed activities. It was found that the aqueous methanol extract of its calyces (B. ceiba calyx extract, BCE) reduced (12.4%) significantly (p < 0.05) the development of sucrose-induced postprandial hyperglycemic load in rats. In-vitro studies revealed that BCE improved glucose-stimulated insulin secretory activity in MIN6 cells plausibly by decreasing ADP/ATP ratio. BCE also augmented concentration-dependent (5 µg, 10 µg, and 20 µg) increase in glucose uptake in hyperglycemic L6 myotubes both by non-insulin-dependent manner (35%, 68%, and 132%, respectively) and insulin-dependent manner (42%, 59%, and 172%, respectively). The insulin-stimulated GLUT4 translocation was compromised (34%) significantly (p < 0.05) under hyperglycemic condition; however, it was improved by 23% and 72% (p < 0.001) when L6 myotubes were primed with 10 and 20 µg of BCE, respectively. Hyperglycemia aggravated reactive oxygen species (ROS) generation in L6 myotubes. The ROS generation was significantly (p < 0.001) reduced by priming myotubes with BCE before challenging myotubes to hyperglycemic environment, possibly by preserving cellular antioxidant enzymes catalase, glutathione peroxidase, and reduced glutathione levels. Phytometabolomic analysis disclosed a number of phytochemicals present in B. ceiba calyces known to display these activities. This is the first study reporting antihyperglycemic activity in B. ceiba calyces, its mechanisms of action, and phytometabolomic profile applying UPLC-QTof-MS/MS technique. PRACTICAL APPLICATION: B. ceiba calyces are part of traditional vegetables. Our study finds that B. ceiba calyces contain phytochemicals possessing antihyperglycemic, insulin secretory, insulin sensitization properties, and potentials for preserving hyperglycemia-induced vitiations in cellular antioxidant defense. These observations provide foundation for exploring further possibilities of B. ceiba calyces to become valuable dietary inclusion in the diet of people suffering from metabolic disorders.

Phytometabolomic analysis of boiled rhizome of Nymphaea nouchali (Burm. f.) using UPLC-Q-TOF-MSE, LC-QqQ-MS & GC-MS and evaluation of antihyperglycemic and antioxidant activities.

Phytometabolomic analysis of Nymphaea nouchali (Burm. F.) boiled rhizome was carried out utilizing UPLC-Q-TOF-MSE, LC-QqQ-MS and GC-MS techniques and evaluated for antihyperglycemic and antioxidative stress potentials. Metabolomic analysis revealed presence of multiple antidiabetic and antioxidant compounds. Boiled rhizome powder exhibited potent antihyperglycemic activity against sugar-induced postprandial hyperglycemia in rats plausibly due to the presence of intestinal α-glucosidase inhibitory and augmenting cellular glucose uptake activities. It also prevented hyperglycemia-induced hemoglobin and insulin glycation. Rhizome displayed potent reducing power, effectively scavenged various reactive oxygen species. It displayed antioxidative stress potential in assuaging H2O2 induced erythrocyte hemolysis and antioxidant activity by inhibiting membrane lipid peroxidation. Boiled rhizome was also found to preserve the loss of cellular antioxidants under H2O2 induced oxidative stress and disturbances caused to mitochondrial membrane potential. This is the first research reporting boiled N. nouchali rhizome as an ideal food material to manage the cause of hyperglycemia and resultant oxidative stress.

Bombax ceiba (Linn.) calyxes ameliorate methylglyoxal-induced oxidative stress via modulation of RAGE expression: identification of active phytometabolites by GC-MS analysis.

Non-enzymatic reactions between proteins and methylglyoxal (MG) result in the formation of advanced glycation end products (AGEs). These AGEs play a vital role in the development of diabetic complications by stimulating oxidative stress and acting upon their receptor RAGE (Receptor for Advanced Glycation End products). This study examined the effect of aqueous methanol extract of Bombax ceiba L. calyxes (BCCE) on MG induced protein glycation and oxidative stress, followed by the identification of phytometabolites present in the calyxes using gas chromatography-mass spectrometry (GC-MS). The study revealed that priming of bovine serum albumin protein with the BCCE inhibited MG induced AGE formation in vitro and restrained AGE-induced RAGE up-regulation in HEK-293 cells. The BCCE significantly (p < 0.001) reduced the MG induced increase in reactive oxygen species (ROS), NADPH oxidase (NOX), and mitochondrial dysfunction. Improvements in the levels of antioxidant enzymes such as Mn and Cu/Zn-superoxide dismutase and glutathione reductase were also observed in HEK-293 cells. Furthermore, the decrease in primary cellular defense against AGEs, the glyoxalase 1 (Glo-1) activity, due to MG treatment was restored in BCCE treated cells. GC-MS analysis revealed the presence of antioxidant and antiglycation compounds such as myo-ionisitol, scopoletin, d-sedoheptulose, succinic acid, and xylitol in B. ceiba calyxes. The observed beneficial effect in our study might be attributed to the presence of these compounds in B. Ceiba calyxes. This is the first report presenting the antioxidant and antiglycation activities of B. ceiba calyxes and GC-MS analysis of active phytometabolites. These observations show that B. ceiba calyxes may become a potent and promising functional food to manage/control the development of diabetic complications.