Parasitic plant in natural Boswellia papyrifera stands at Humera, Northern Ethiopia

In Boswellia papyrifera （Del.） Hochst natural stands, we stud- ied the association of parasitic plants with B. papyrifera trees from which frankincense was tapped and marketed for domestic and export markets. Data on the rate of infection of parasitic plants on B. papyrifera was collected in three transects located at separate locations around Baha kar, northern Ethiopia. Each transect had ten circular sample plots of 400 m2 and separated by 100 m. Species composition, DBH, height, crown di- ameter, number of main, secondary and tertiary branches and number of parasitic plants on individual trees were recorded. Sixteen tree species were recorded in the combined sample plots. The parasitic plant associ- ated with B. papyrifera was identified as Tapinanthus globiferus. This parasite infected 38% of Boswellia trees in sample plots. The infection rate of the parasitic plant varied from 1 to 33 per Boswellia tree. The infection of T. globiferus on B. papyrifera was predominantly limited to tertiary small branchlets arising from secondary branches; parasitic plants were absent on thick main and secondary branches. In all plots, infectionof T. globiferus was exclusively limited to Boswellia trees. The influence of T. globiferus parasitism on growth of Boswellia trees and its influence on yield of incense production needs further investigation. Management of natural stands for frankincense production should include measures to reduce infection by T. globiferus.

Chemical composition, antiproliferative, antioxidant and antibacterial activities of essential oils from aromatic plants growing in Sudan

Objective: To explore the potential of essential oil, as therapeutic molecule source, from olibanum of Boswellia papyrifera(Burseraceae), leafy stems of Cymbopogon schoenanthus(Poaceae) and Croton zambesicus(Euphorbiaceae) and rhizome of Cyperus rotundus(Cyperaceae) found in Sudan. Respective essential oil was evaluated for antiproliferative, antibacterial and antioxidant activity. Methods: Essential oils were extracted by hydrodistillation and then analysed by gas chromatography coupled to mass spectrometry(GCMS). Anti-proliferative activity was determined against human cell lines(MCF7 and MDAMB231, HT29 and HCT116) by the thiazolyl blue tetrazolium bromide(MTT) procedure. Antioxidant activity was evaluated by diphenyl 2 pycril hydrazil(DPPH) assay. Antibacterial activity was determined against two Gram-positive and two Gram-negative bacteria by microdilution method. Results: The essential oil from olibanum of Boswellia papyriferacontained mainly alcohol and ester derivatives(46.82%) while monoterpenes(69.84%) dominated in Corton zambesicus oil. Sesquiterpenes were the most highly represented classes of terpene derivatives in Cyperus schoenanthus(71.59%) and Cyperus rotundus(44.26%). Oil of Cymbopogon schoenanthus revealed the best anti-proliferative activity against HCT116 cell line with IC50 value at(19.1 ± 2.0) μg/m L. Oil of Croton zambesicus showed the best antioxidant activity [EC50(4.20 ± 0.19) mg/m L]. All oils showed good antibacterial activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus with minimum inhibitory concentration(MIC) value ranged from 16 to 250 μg/m L. Conclusions: The results suggest that the essential oils of these plants could be used as a source of natural anti-proliferative, antioxidant and antibacterial agents.