Antioxidant and antimicrobial properties of the essential oil and extracts of Zanthoxylum alatum grown in north-western Himalaya.

The essential oil obtained from the fresh leaves of Zanthoxylum alatum was analysed by gas chromatography/mass spectrometry (GC/MS). Fourteen components were identified, and linalool (30.58%), 2-decanone (20.85%), ß -fenchol (9.43%), 2-tridecanone (8.86%), ß -phellandrene (5.99%), Sabinene (4.82%), and α -pinene (4.11%) were the main components. The EO and methanolic extract of Z. alatum exhibited potent antifungal activity against Alternaria alternata, Alternaria brassicae, and Curvularia lunata. The EO also showed significant antibacterial activity against Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, and Escherichia coli. Further, antimicrobial constituents of the EO were isolated by bioautography and preparative thin layer chromatography (PTLC) and identified as ß -fenchol and linalool using GC/MS analysis. In addition to this, the free radical scavenging activity and antioxidant potential of EO and methanolic extract/fractions of Z. alatum were also investigated using in vitro assays including scavenging ability against DPPH(•), reducing power and chelating ability on Fe(2+) ions. Our results demonstrate that Z. alatum could be used as a resource of antioxidant and antimicrobial compounds which may find applications in food and pesticide industries.

Antioxidant activity and protective effect against plasmid DNA strand scission of leaf, bark, and heartwood extracts from Acacia catechu.

UNLABELLED: The antioxidant activity of methanol extract/fractions of leaf, bark, and heartwood of Acacia catechu was evaluated by various antioxidant assays, including free radical, superoxide and hydroxyl radical, reducing power, metal ion chelation, as well as hydroxyl radical induced DNA strand scission. The leaf, bark, and heartwood powder was extracted in methanol and the lyophilized methanol extract was fractionated with different solvents in the order of increasing polarity. The results indicate that ethyl acetate fraction of heartwood has the highest antioxidant capacities, presenting lower EC(50) values particularly in free radical scavenging activity, including DPPH radicals (4.76 ± 0.14 µg/mL), superoxide anions (26.21 ± 0.79 µg/mL), and hydroxyl radicals (33.69 ± 1.42 µg/mL), in direct assay systems. Reducing power was also highest in ethyl acetate fraction of heartwood (EC(50) of 79.05 ± 1.02 µg/mL). As for the chelating power on ferrous ions, leaf extract was more effective than bark and heartwood extracts. Furthermore, the ethyl acetate and acetone fractions of heartwood significantly protected pBR322 supercoiled plasmid DNA against strand scission induced by hydroxyl radicals in a Fenton's reaction mixture. PRACTICAL APPLICATION: The present investigation suggests that the three organs of A. catechu differ significantly in their antioxidant potential as seen in the DPPH radical scavenging assay, reducing power assay, metal ion chelating assay, superoxide radical scavenging assay and hydroxyl radical scavenging assay. Further, our results showed that crude methanol extract and ethyl acetate fraction of heartwood of A. catechu might have a good potential as a source for natural health products due to its antioxidant and DNA protective activities.

Antioxidant activity of acetone extract/fractions of Terminalia bellerica Roxb. fruit.

Terminalia bellerica Roxb. (Family: Combretaceae) has been valued in Indian system of medicine for treatment of wide range of diseases and reported to have antioxidant properties. In the present study, the free radical scavenging activity and antioxidant potential of acetone extract/fractions of its fruit was investigated using in vitro assays, including scavenging ability against 2,2'-diphenyl-2-picrylhydrazyl (DPPH), beta-carotene bleaching inhibition, reducing power and chelating ability on Fe2+ ions. The fruit powder was extracted at room temperature with different solvents in the order of increasing and decreasing polarity to obtain crude acetone extract which was further partitioned with ethyl acetate and water (1:1). It was found that ethyl acetate fraction was more effective than crude acetone extract in all antioxidant assays, except chelating power which was highest in water fraction. Maximum antioxidant activities (expressed as EC50 values) observed were 14.56 microg/ml, 27.81 microg/ml and 67.8 microg/ml in DPPH, beta-carotene bleaching and reducing power assays, respectively. The antioxidant potential was compared with known antioxidant (butylated hydroxyl toluene) and correlated with total phenolic and flavonoid content in crude extract and fractions. Fractions rich in polyphenolic content were more effective than the crude extract.