13 and 16 Phenolic compounds are often linked with other biomolecules, such as polysaccharides, proteins, etc., therefore, an appropriate solvent system is required for their extraction. Polarity of different solvents is likely to have significant consequence on polyphenolic http://www.selleckchem.com/products/jq1.html content and antioxidant activity as well. 17 Importance of solvent system has

also been reported in determination of antimicrobial activity 5 in ginkgo leaf extracts. Among the three assays used for determination of antioxidant activity in the present study, ABTS gave best results followed by DPPH and FRAP. ABTS is soluble in both aqueous and organic solvents and having reducing properties of 2, 2-azinobis-(3-ethylbenzoline sulphonate) radical, in which the antioxidant activity can be précised due to the hydrophilic and lipophilic nature of the compound. DPPH, possessing ability to get dissolved only in organic solvent, ethanol in particular, can be predicted as an imperative restriction while interpreting the role of hydrophilic antioxidants. Previous studies have also indicated the merits of using ABTS assay in assessing antioxidant potential of plant extracts.18

With regard to the FRAP, the antioxidants reduce the ferric ion/ferricyanide complex to the ferrous form, the Perl’s Prussian blue complex. The reducing power is related to the presence of the compounds, which apply their action by flouting the BLU9931 free radical chain through donating hydrogen atom compounds.19 The reducing power of extracts prepared from ginkgo leaves has been reported.20 Correlation matrix exhibited significant positive relationship between total phenolic and flavonoid contents and the antioxidant activity performed by all the three assays (Table 2). Linear regression analysis revealed that total phenolic content contributes 14.1–51.2% of radical scavenging property (r2 = 0.141 for DPPH and 0.512 for ABTS) and 53.8% of reducing property (r2 = 0.538) ( Fig. 4A–C). Likewise, total flavonoid content contributes 3.7–40% of radical scavenging property (r2 = 0.037 for DPPH and 0.408 for ABTS) and 37% of reducing property (r2 = 0.376) ( Fig. 5A–C). Similar findings

have been reported in other Himalayan species as well where total phenolic content and antioxidant activity correlate positively. 18 The IHR harbors until plethora of medicinal plants. While the natural habitat of ginkgo is in China, Japan, and Korea, some established trees have been reported from the hilly areas of IHR, maximum being in the state of Uttarakhand. Ginkgo possesses high amounts of phenolic contents and high levels of gallic acid equivalents. Ginkgo trees, being in limited number and growing under low temperature climatic conditions, extend opportunity to make use of these trees for understanding the physiological aspects, such as accumulation of phytochemicals, production of antimicrobials, with emphasis on propagation and conservation of the species.5, 21, 22 and 23 All authors have none to declare.