Validated reversed-phase column high-performance liquid chromatographic method for separation and quantification of polyphenolics and furocoumarins in herbal drugs.

A rapid column high-performance liquid chromatographic-photodiode array method has been developed for the separation and identification of secondary metabolites, especially different types of phenols and furocoumarins, in a 35 min chromatographic run. The method has been optimized and validated for selectivity, precision, recovery, and robustness with the aim of application for standardization of selected herbal drugs. Almost all of the tested compounds had linearity of >98%, with relative standard deviation <10% in terms of variation of retention time. Interday and intraday variability was <5%. The developed method has been successfully applied in identification and quantification of phenols and furocoumarins present in different plants, viz., Artemisia pallens (whole plant), Hibiscus rosa-sinensis DC (flower), Heracleum candicans DC (fruit), and Ficus carica Linn (bark). The results indicate that the method is rapid, accurate, and robust for the analysis of different types of phenols and furocoumarins and, hence, can be successfully used in the quality control and standardization of plant extracts and herbal drugs.

Novel mechanism of modulating natural antioxidants in functional foods: involvement of plant growth promoting Rhizobacteria NRRL B-30488.

The significance of plant growth-promoting rhizobacteria (PGPR) mediated increase in antioxidant potential in vegetables is yet unknown. The plant growth-promoting bacterium Bacillus lentimorbus NRRL B-30488 (B-30488) mediated induction of dietary antioxidant in vegetables ( Trigonella foenum-graecum, Lactuca sativa, Spinacia oleracea, and Daucus carota) and fruit ( Citrus sinensis) after minimal processing (fresh, boiled, and frozen) was tested by estimating the total phenol content, level of antioxidant enzymes, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide scavenging activities along with integral radical scavenging capacity by photochemiluminescence assay and inhibition of lipid peroxidation. Minimal processing of vegetables showed that T. foenum-graecum had the highest phenol content in B-30488-treated plants followed by L. sativa, D. carota, and S. oleracea. Thermally treated vegetables T. foenum-graecum (26-114.5 GAE microg mg (-1)) had an exceptionally high total phenolic content, followed by D. carota (25.27-101.32 GAE microg mg (-1)), L. sativa (23.22-101.10 GAE microg mg (-1)), and S. oleracea (21.87-87.57 GAE microg mg (-1)). Among the vegetables and fruit used in this study for enzymatic estimation, induction of antioxidant enzymes, namely, polyphenol oxidase (PPO), ascorbate peroxidase (APX), catalase (CAT), and superoxidase dismutase (SOD), was observed in edible parts of T. foenum-graecum, L. sativa, S. oleracea, and D. carota, after inoculation with B-30488. The scavenging capacity of the vegetables treated with B-30488 against DPPH and superoxide anion radical activity was found to be significantly high as compared to nontreated control. Mild food processing had no adverse effect on radical scavenging capacity. Photochemiluminescence also ascertains the above findings. The ability of the plant extracts to protect against lipid peroxidation and its ability to prevent oxidation of reduced glutathione (GSH) was measured in rat liver homogenate, and the results suggested that the inoculated plant exhibited better activity in all of the screened plants. Significant increases in shoot length, root length, and dry weight, averaging 164, 132, and 135% in T. foenum-graecum, 174, 141, and 156% in L. sativa, 129, 141, and 59%, in S. oleracea, and 125, 146, and 42% in D. carota, respectively, over untreated controls, were attained in greenhouse trials. To the best of the authors' knowledge, this is the first report of PGPR-mediated induction of antioxidant enzyme activity (PPO, APX, CAT, and SOD) along with the antioxidant activity of the extracts in both in vitro (DPPH radical scavenging and superoxide scavenging) and ex vivo conditions using the rat liver tissue (percent inhibition of lipid peroxidation and prevention of oxidation of GSH) and phenolic content. The results demonstrate the PGPR-mediated induction of antioxidant level in vegetables and fruit controls oxidative damage even after minimal processing and thus is indicative of its potential as a viable substitute of synthetic antioxidants.

Effect of Desmodium gangeticum extract on blood glucose in rats and on insulin secretion in vitro.

Desmodium gangeticum is widely used in the indigenous system of medicine in India and is reported to contain flavone and isoflavonoid glycosides. It forms the ingredient of many Ayurvedic formulations used for diabetes. The present study was thus aimed at evaluating the insulin secretion and antidiabetic activity of Desmodium gangeticum. Treatment of diabetic rats with aerial parts of D. gangeticum extract (DG, 100 and 250 mg/kg body weight) for 3 weeks showed a significant reduction in blood glucose. D. gangeticum extract caused a significant increase in insulin secretion from MIN6 cells grown as monolayers and as pseudoislets, indicating that the antidiabetic activity may be as a result of increased insulin secretion. It also had a role on the lipid profile of the rats by causing reductions in cholesterol and triglycerides and increasing the HDL significantly (p < 0.05). This works supports the traditional use of D. gangeticum in the treatment of diabetes and this is likely to be due, at least in part, to its stimulation of insulin secretion by pancreatic islet cells.

Antioxidant activity of Desmodium gangeticum and its phenolics in arthritic rats.

Total alcoholic extract of Desmodium gangeticum, which exhibited significant anti-inflammatory activity, was evaluated for the possible mode of action by studying its antioxidant potential in adjuvant-induced arthritic rats. Activity guided fractionation and isolation were carried out. The phenolics fraction showed maximum potency. Solid phase extraction followed by preparative HPLC of the active phenolic fraction yielded for the first time two potent antioxidant compounds, caffeic acid and chlorogenic acid, from this plant. The biological antioxidant defense system, involving superoxide dismutase, glutathione and catalase, showed a significant increase with their levels close to the normal control with a decrease in the lipid peroxide content upon administration of D. gangeticum extract (100 mg kg(-1)) and its phenolics (50 mg kg(-1)) in arthritic rats, thereby indicating the extracts antioxidant property under arthritic conditions.

Free radical scavenging potential of Saussarea costus.

Saussurea costus (Falc.) Lipschitz from the family Asteraceae is an important medicinal drug, the roots of which are widely used in folk medicine. The antioxidant activity of the plant has been studied using its ability to scavenge DPPH, nitric oxide, superoxide radicals along with its ability to inhibit lipid peroxidation and GSH oxidation. The 1 mg mL(-1) extract had antioxidant activity with 85.2% reduction of DPPH and a 72.7% decrease in lipid peroxidation. It showed maximum inhibition of superoxide radical of 66.0%, and 58.4% inhibition of nitric oxide formation. The concentration of chlorogenic acid was 0.027% in the extract of S. costus. Thus, the therapeutic activity of the plant may be due to its antioxidant activity, probably as a result of the presence of chlorogenic acid.