Screening of Antioxidant Potential of Selected Barks of Indian Medicinal Plants by Multiple in vitro Assays

Objective To evaluate the antioxidant potential in herbal extract barks of five therapeutically important medicinal plants native to India, i.e. Crataeva nurvala Buch.-Ham., Buchanania lanzan Spreng., Aegle marmelos Corr., Dalbergia sissoo Roxb. ex DC., and Cedrela toona Roxb. Methods Standardized aqueous alcoholic extracts from the selected barks having different target radicals, such as superoxide radical, nitric oxide, ABTS radical, and peroxidative decomposition of phospholipids, were prepared and screened by multiple in vitro assays. These extracts were also tested for total phenolic and tannin content and correlated with antioxidant capacity. Results Total phenolic and tannin contents were found to be the highest in C. nurvala （195 GAE mg/g and 218.3 mg/g CE）. SOD mimetic activity was found to be the highest in Crataeva nurvula, although all barks showed activity more than IO3 units/mg extract. Lipid peroxidation inhibitory potential was found to be the highest in Crataeva nurvala （83.4% inhibition of MDA formation/10 μg extract）, and also showed a comparatively high NO quenching capacity （45.5% per 10 μg extract）. The highest NO quenching potential was found in Aegle marmelos （47.3% per 10 μg extract）. Cedrela toona showed the lowest LPO inhibitory potential and NO quenching capacity （50.5% and 30.5%, respectively）. Buchanania lanzan, a medicinal plant extensively used for inflammatory disorders and Dalbergia sissoo also showed 72.5% and 69.1% LPO inhibitory potential/10 μg extract. Trolox equivalent antioxidant capacity ranged from 0.24 to 0.39 mmol/L TEAC/mg extract, indicating that all the barks tested had ABTS^＋ radical quenching capacity. Conclusion Bark of Crataeva nurvula has the highest antioxidant capacity and a positive correlation between antioxidant activity and their plendic content was found.

Study on Antifungal Activity of Some Medicinal Plants against Gray Mold(Botrytis cinerea)

In order to investigate antifungnl effect of medicinal plant extracts on Botrytis cinerea, the antifungal activity of ethanol extracts of 8 medicinal plants in- eluding Ginkgo biloba against Botrytis cinerea was determined by growth rate method. The results showed that Ginkgo biloba and Ginnamomum cassia extracts had significant inhibition effects on B. cinema mycelium growth （P 〈 0.05）, with inhibition rates over 70% and ECho values of 0.027 mg/ml and 0.039 mg/ml, re- spectively, significantly different from the antifungal effects of other kinds of medicinal plants ; and P. ternata and A. tsaoko extracts showed the second highest in- hibition effects, with ECho values of 0. 011 9 and 0. 039 3 mg/ml, respectively. Further experimental application could be carried out.

Antimicrobial Agents from Selected Medicinal Plants in Libya

Objective： To test the in vitro antimicrobial efficacy of water and methanol extracts of 23 plant species that are commonly used in Libyan folk medicine. Methods： The antimicrobial activity was determined using the well-diffusion method. Four test microorganisms were used namely, Escherichia coil, Salmonella species, Staphylococcus aureus and Bacillus subtilis. The minimum inhibitory concentration （MIC） was determined for the high biologically active crude plant extracts. Results： Among 23 medicinal plants used in the study, only 5 methanolic extracts [Rosmarinus offcinalis L., Carduus marianium L., Lantana camara L., Rhus tripartite （ueria） Grande, and Thymus capitatus （L.） Hoffm （link）] showed the highest antimicrobial activity against Staphylococcus aureus, Bacillus subtilis and Salmonella species, while 22 methanolic and aqueous extracts showed moderate to weak antimicrobial activity on all tested organisms. However 19 of the extracts showed no activity at all against Gram -ve and Gram ＋ve microorganisms. MIC was found to be 1.25 mg/mL （Thymus capitatus）, 3 mg/mL （Rhus tripartite）, 4 mg/mL （Carduus marianium）, 5 mg/mL （Rosamarinus officinalis） and 5 mg/mL （Lantana camara）, respectively. Condusions： The present results revealed that, crude methanolic extracts of the investigated Libyan folk medicinal plants exhibited mild to high in vitro antibactedal activities against Gram-positive and Gram-negative microorganisms.

Aeromonas veronii isolated from climbing perch(Anabas testudineus)suffering from epizootic ulcerative syndrome(EUS)

Motile Aeromonads are responsible for various diseases in fishes that cause significant economic losses in aquaculture.Aeromonas spp.are also frequently isolated from fish suffering from Epizootic Ulcerative Syndrome(EUS).The present study was conducted to isolate and identify A.veronii from Vietnam climbing perch(Anabas testudineus)suffering from EUS,evaluate the pathogenicity of the isolates,and find out antibiogram profile and susceptibility of the isolates to medicinal plant extracts.Vietnam climbing perch(A.testudineus)suffering from EUS was collected from fish farms located at Savar,Dhaka and bacteria were isolated from the external ulcerative lesion,and kidney and liver of the infected fish on nutrient agar plates.Preliminary phenotypic identification of the bacterial isolates was performed following morphological,physiological and biochemical characterization tests.The 16S rRNA gene sequencing was accomplished for further molecular identification of five selected isolates.To evaluate the pathogenicity of the isolates in vivo artificial infection challenge test was conducted through immersion method.Another in vivo pathogenicity test was done at three different temperatures(18◦C,28◦C,and 37◦C)to examine the effects of temperature on the pathogenicity of the isolates.Ten commercial antibiotics were used to find out the antibiogram profile of the isolates.Finally,susceptibility of the isolates was screened against 19 medicinal plants extracts.A total of 38 out of 46 isolates isolated from Vietnam climbing perch(A.testudineus)suffering from EUS were phenotypically identified as Aeromonas sp.Five randomly selected isolates were further confirmed as A.veronii by analyzing the 16S rRNA gene sequence homology.The pathogenicity of the isolates was found moderate to high(41%-80%mortality)in the artificially challenged fish.The highest and lowest mortality was obtained in the fish challenged with the isolates BFKA33 and BFKA12,respectively.The isolates were found resistant to several antibiotics,including amoxicillin,ampicillin,penicillin-G,and vancomycin.Nevertheless,extracts of three medicinal plant(Allium sativum,Syzygium aromaticum,and Tamarindus indica)demonstrated antibacterial activity to the isolates(BFKA12,BFKA15,BFKA18,BFKA29,and BFKA33).