M. M. Khan

Antioxidant and Antipathogenic Activities of Citrus Peel Oils

Abstract The present study was focused on unexplored Pakistani citrus species viz. sweet oranges (Citrus sinensis Vars. Jaffa, Blood Red and Mosambi), Mandarins (Citrus reticulata Var. kinnow) and grapefruits (Citrus paradisi Var. Shamber) for peel oil yield, chemical composition and antipathogen activities. The chemical composition of citrus peel oil was analyzed through gas chromatographic - mass spectrometric analysis. Six compounds viz. D-limonene, d-carvone, Z-5-nonadecane, thujol, trans-P-mentha-2,8-dienol and heneicosane were commonly present in all cultivars. However, D-limonene (40.9–76 %) was a major compound in all citrus peel oils. The high amounts of phenolic compounds were recorded in the peel oil with a maximum amount in grapefruit (8.58 mg/g) and minimum in Kinnow mandarin (5.20 mg/g). Jaffa orange cultivar showed a highest radical scavenging activity (70.14 %). Furthermore, peel oils were tested for their antimicrobial activities against five pathogenic bacterial strains viz. Staphylococcus aureus, Eschrichia coli, Salmonella typhi, Proteus vulgaris, Staphylococcus epidermidisand two pathogenic fungal strains viz. Aspergillus flavus and Trichophyton alba. Citrus peel was found effective against all tested micro-organisms and in particular Jaffa orange essential oil was highly effective against all microbial strains growth and Salmonella typhi was the most inhibited strains among all.

Clonal multiplication of guava (Psidium guajava) through soft wood cuttings using IBA under low-plastic tunnel

The present investigation on clonal multiplication of guava (Psidium guajava L.) soft wood cuttings was done with the aim to determine the most successful media and rooting hormone (IBA) concentration. Guava soft wood cuttings were treated with 0, 200, 400 and 600 mg kg -1 IBA solution when planted in three different rooting media (sand, silt and top soil) under low-plastic tunnel. The cuttings were allowed to grow under low-plastic tunnel for 90 day to evaluate the rooting capability and shooting competency. The study showed that the species has a great potential for clonal multiplication through soft wood cuttings. The highest number of roots and root length were observed in the cutting treated with 400 mg kg -1 IBA solution in sand, and the lowest in the cuttings without IBA treatment in sand media. In general 400 mg kg -1 IBA treatment with silt as rooting media performed better as compared to the other treatments. However, the highest survival percentage (50%) was observed in the cuttings rooted in silt media and treated with 200 mg kg -1 IBA solution. Experimental results showed the potential of clonal propagation of guava through soft wood cuttings treated with auxin under simpler and cheaper low-plastic tunnel.