• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.6
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• pp.1564-1568
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• 2007

In this study fourteen ethanol extracts from Nepalese medicinal plants were screened for their in vitro antimicrobial and antiradical activity and their total phenolic content was evaluated. The antiradicalactivity was evaluated by free radical scavenging assay, using 2,2-diphenyl-1-picryl hydrazyl radical (DPPH). Plant extracts showed a wide range of radical scavenging activity, with $IC_50$ value ranging in between $5.38\; {\mu}g/\;mL$ - $429.61\;{\mu}g/mL$. Strong radical scavenging activity was shown by flower extract of Woodfordia fruticosa ($5.38\;{\mu}g/\;mL$) and stem bark extract of Azadirachta indica ($5.58 {\mu}g/\;mL$)that also contained high phenolic content. Most of the sample showed activity below the concentration of $100\; {\mu}g/mL$. For antimicrobial activity three test microorganisms namely Staphylococcus aureus, Streptococcus epidermidis, and Candida albicans were used. The minimum inhibitory concentration (MIC) of the plant extracts was determined. Most of the plant extracts were effective against bacterial strains only at higher concentration ($800\;-\;1,600\;{\mu}g/mL$) but none of these were effective against Candida albicans below $1,600\;{\mu}g/mL$.

• Microbiology and Biotechnology Letters
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• v.38 no.2
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• pp.183-189
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• 2010

In the course of screening for anti-acidosis and anti-diabetes agent from natural products, the inhibitory activities of Nepales plant extracts against microbial $\alpha$-amylase and $\alpha$-glucosidase were evaluated. Among the 100 different kinds of ethanol extracts, Cedrus deodara (Roxb.) G. Don and Myrica nagi Thunb showed strong inhibition activities against $\alpha$-amylase. The $IC_{50}$ values of C. deodara (Roxb.) G. Don, M. nagi Thunb and acarose, a commercial available anti-diabetes agent, were 44.5, 47.5 and $50.5\;{\mu}g/mL$, respectively. Considering the crude extract of C. deodara (Roxb.) G. Don, and M. nagi Thunb, these extracts have strong potentials as anti-acidosis or anti-diabates agent. In a while, Cleistocalyx operculatus (Roxb.) extract showed a good inhibition activity to $\alpha$-amylase and $\alpha$-glucosidase, even it was recently reported. The selected three extracts did not show any hemolysis activity against human red blood cell up to 1 mg/mL, and the inhibition activities were maintained by heat or acid treatment. Moreover, treatment of HCl (0.01N) for 1 h into C. operculatus (Roxb.) and M. nagi Thunb increased the inhibition activity from 50% to 70%. Our results suggest that C. deodara (Roxb.) G. Don, M. nagi Thunb, and C. operculatus (Roxb.) are potential as anti-acidosis and anti-diabetes agents.